CASP8 gene. It has been reported that the six-nucleotide deletion polymorphism (-652 6N del) of the CASP8 gene had effect on some cancer risk. Few studies explored the association between CASP8 gene polymorphism and digestive tract cancer risk. To evaluate the association between the CASP8 -652 6N del polymorphism and the risk of digestive tract cancer, we conducted this meta-analysis. We found that CASP8-652 6N del polymorphism was associated with a significantly reduced risk of digestive tract cancer in the co-dominant model . In the stratified analysis by cancer types, we found that all genetic models had protective effect on gastric cancer. Similar results were observed for colorectal cancer under heterozygote comparison and dominant model, but not under homozygote comparison or recessive model. In addition, a significantly decreased risk was found on esophageal cancer for most genetic models, except heterozygote comparison. When stratified by ethnicity and source of control, an evidently decreased risk was identified in the Asian populations and population-based studies. In conclusion, there exists an association between the CASP8 -652 6N del polymorphism and reduced digestive cancer risk, especially among Asians and population-based studies.Caspase-8 (CASP8) is one key regulator of apoptosis of T lymphocytes and is encoded by the  Several meta-analyses have confirmed that the gene variants of caspases-2, 5, 7, 8, 9 and 10 disturbed the apoptotic mechanism and thus affected the risk of some cancers[3–.The activity of many genes influences a cell's likelihood of activating its apoptotic programCASP8 gene. The CASP8  gene contains at least 11 exons spanning ~30 kb on human chromosome band 2q33–34 and encodes 479 amino acids, including prodomain and caspase domain. There are 353 single-nucleotide polymorphisms (SNP) of the CASP8 reported in the dbSNP database. It has been reported that polymorphic variation in CASP8 influences cancer risk, such as the variant D302H (rs1045485), the 652 6N insertion/deletion (ins/del) promoter variant (rs3834129), and the IVS12-19G/A (rs3769818). Previous meta-analysis suggested CASP8 -652 6N promoter polymorphism is associated with reduced renal cell carcinoma risk and breast cancer risk. However, there was no evidence on the association between the -652N ins/del and digestive tract cancer due to limited publications. Digestive tract cancers represent a homogeneous group of malignancies. Given the amount of data now available on the association between CASP8 -652 6N promoter polymorphism and digestive tract cancer susceptibility, we performed the meta-analysis based on published case-control studies.Caspase-8 (CASP8) is a key regulator of apoptosis of T lymphocytes and is encoded by the We carried out a search in PubMed and Embase databases with the following keywords: . The titles and abstracts of all eligible studies were examined carefully, and the bibliographies of the selected papers were also checked manually. If the same patient population was included in multiple publications, only the most recent or complete study was used in this meta-analysis.CASP8 -652 6N promoter polymorphism and digestive system cancer risk; (c) data available on genotype frequency or the value of the OR.Selected studies in our meta-analysis had to meet all the following criteria: (a) only case-control or cohort studies; (b) evaluation of the Table 1). Data were independently extracted by two investigators. If consensus was not reached by discussion, the third investigator was rereading.For each study, the following information was extracted by two evaluators: first author's name, year of publication, country, ethnicity, source of control, sample size and genotyping results of cases and controls (CASP8 -652 6N promoter polymorphism and digestive system cancer risk. The pooled ORs were performed for homozygote comparison (del/del vs. ins/ins), heterozygote comparison (del/ins vs. ins/ins), dominant model (del/ins+ del/del vs. ins/ins), and recessive model (del/del vs. del/ins+ ins/ins), respectively. P<0.05 was considered as statistically significant. Subgroup analyses were carried out by the cancer types and ethnicity, respectively. We used either the fixed (Mantel-Haenszel) or random (DerSimonian-Laird) effects models to get pooled ORs. If the P was more than 0.05 for the Q-test, the heterogeneity was considered significant. When there was no heterogeneity among studies, the pooled OR estimate of each study was calculated by the fixed-effects model. Otherwise, the random-effects model was used. The Begg's test and the Egger's test were used to test possible publication bias in this meta-analysis. Hardy–Weinberg equilibrium (HWE) in the controls was evaluated using the chi-square test. Meta-analyses were performed using Stata 11.0 software.Our meta-analysis assessed the overall association between Table 1, 18 separate studies including a total of 15,086 patients and 16,374 controls were finally retrieved. Among them, there were 3 esophageal cancer studies[12,15–, 3 gastric cancers[12,15, and 12 colorectal cancers (including studies)[15,18– . In addition, there were 9 studies in Asians populations, 9 in Caucasians populations and 13 were population-based studies, and 5 hospital-based studies. The distribution of genotypes in the controls was consistent with HWE, except for only one study .As shown in CASP8-652 6N del polymorphism for the co-dominant model ; dominant model , recessive model .Overall, a significant reduced risk of digestive tract cancer was associated with the  vs. ins/ins: OR= 0.43, 95%CI= 0.28–0.67; del/ins vs. ins/ins: 0.79 (0.63–0.99); del/ins+ del/del vs. ins/ins: 0.73 (0.59–0.95); del/del vs. del/ins+ ins/ins: 0.50 (0.33–0.77). Similar results were observed for colorectal cancer under heterozygote comparison  and dominant model , but not under homozygote comparison or recessive model. In addition, a significant decreased risk was found on esophageal cancer for the mostly genetic models: del/del vs. ins/ins: 0.56 (0.40–0.78); del/ins+ del/del vs. ins/ins: 0.83 (0.71–0.97); del/del vs. del/ins+ ins/ins: 0.57 (0.41–0.79), except the heterozygote comparison.In the stratified analysis by cancer types, we found all genetic models had protective effect on gastric cancer: del/del vs. ins/ins: OR= 0.62, 95%CI= 0.51–0.76, Supplementary Fig. 2A, available online; del/ins vs. ins/ins: OR= 0.87, 95%CI= 0.79–0.95, Supplementary Fig. 2B, available online; del/ins+ del/del vs. ins/ins: OR= 0.83, 95%CI= 0.76–0.91, Supplementary Fig. 2C, available online; del/del vs. del/ins+ ins/ins: OR= 0.61, 95%CI= 0.46–0,83, Supplementary Fig. 2D, available online). In stratified analysis by source of control, we found significant reduced CRC risk in population-based studies , but not in hospital-based studies (figure not shown).When stratified by ethnicity, two distinct results appeared in Asian populations and European populations. An evidently decreased risk for Asian populations in any genetic models .Begg's funnel plot and egger's test were used to assess the publication bias. As shown in , the overall result did not been influenced significantly . The sensitivity analysis results revealed that no individual studies significantly affected the pooled ORs under heterozygous model of CASP8 -652 6N polymorphism , suggesting that our results are stable.Sensitivity analysis was conducted repeatedly when the special studies had been left out at a time. For example, after excluding the study deviated from HWETable 2). To explore the source of heterogeneity, we conducted a subgroup analysis by cancer types, ethnicity and the source of control. As a result, there presented little or no heterogeneity across studies. Furthermore, we found that colorectal cancer, Caucasian and population-based studies contributed to substantial heterogeneity.There was potential heterogeneity among studies in overall analysis and some subgroup analysis under homozygous and recessive model . The-652 6N del variant involves a six-nucleotide deletion in the promoter region of the CASP8 gene. The deletion abolishes an Sp1 binding site and is associated with decreased RNA expression in lymphocytes and lower CASP8 activity and activation-induced cell death of T lymphocytes.Apoptosis plays critical roles in a wide variety of physiologic processes during fetal development and in adult tissues. Previous studies found that genetic mutations of caspases 8 in tumor cells reduce the cell sensitivity to apoptosis, which may be related to the occurrence and development of tumors. Our meta-analysis based on 18 case-control studies suggested that the CASP8 -652 6N del polymorphism is associated with decreased risk of digestive tract cancer, which was similar with the results of Yin et al. and Zhang et al.. However, there was potential heterogeneity under the four genetic models in digestive system cancer. Therefore, we also carried out the stratification analysis by ethnicity, cancer type and source of control. In stratification by cancer type, we also found the reduced cancer risk remained for subgroups of colorectal cancer, gastric cancer and esophageal cancer. What is more, similar results were found in Asians and population-based studies. Peng et al. reached a similar conclusion that CASP8 -652 6N ins/del polymorphism may play a protective role in colorectal cancer development. But their sample size was relatively small, not having enough statistical power to explore the real association. Our study with a large sample size provides additional evidence of the association between CASP8 -652 6N ins/del polymorphism and colorectal cancer risk.It is known that apoptosis plays an important role in cancer growth, progression, and drug resistance. On the other hand, the insufficient hospital-based samples tended to have underestimated cancer risks.There was a significant reduced association between the-652 6N del polymorphism and digestive tract cancer risk among Asian populations, but not in Caucasians. One explanation may be genetic differences and diverse living environments between Asian and Caucasian populations. On the other hand, the Asian population are relatively homogeneous, who mainly come from Han Chinese. However, Caucasian population consisted of people from various countries with diverse living environments. Difference between Asians and Caucasians may explain the distinct findings. In addition, gene-gene and gene-environmental interactions may lead to the result bias. Among the included studies, 13 were population-based samples and 5 were hospital-based samples, respectively. Borderline significantly decreased risks were found for population-based studies. One explanation may be the hospital-based studies have some biases because such controls may be a sample of ill-defined reference population, particularly when the genotypes under investigation were associated with the disease conditionsSome limitations of this meta-analysis should be addressed. First, in the subgroup analyses of cancer type, the number of esophageal cancer and gastric cancer were relatively small, not having sufficient statistical power to explore the real association. Second, our results were based on unadjusted estimates, because not all published studies presented adjusted ORs. More precise analysis should be carried out, which would allow for the adjustment by other variance, such as sex, age, smoking status, drinking status, obesity and other lifestyles. Thirdly, the experiment method for each study was without restrictions, which affected the accuracy of the results to a certain extent.CASP8-652 6N del polymorphisms and reduced digestive tract cancer risks, especially in Asians. Future studies with large sample sizes are required to confirm current findings.In conclusion, our meta-analysis supports the association between the


The role of environmental factors and genetic susceptibility in the development of colon cancer (CC) has been already proven, but the role of gene polymorphisms in modifying the risk of environmental factors such as nutritional factors is still unknown. This study aimed to investigate the effect of polymorphisms of involved genes in the association between red meat consumption and the development of CC. The present review was carried out using keywords such as polymorphism and/or protein and/or red meat and/or processed meat and/or colon cancer. PubMed and Science Direct databases were used to collect all related articles published from 2001 to 2017. The presence of SNP in the coding genes of proteins involved in metabolism of nutrients could play significant roles in the extent of the effects of nutrition in the development of CC. The effect of dietary proteins greatly depends on the polymorphisms in the metabolising genes of these substances. Gene polymorphisms may have a role in colorectal cancer risk, especially in people with high meat intake, and this leads to a difference in the effects of meat consumption in different individuals. To conclude, dietary recommendations for the prevention and control of CC should be modified based on the genotype of different individuals. Increasing our knowledge on this field of nutritional genomics can lead to personalised preventive and therapeutic recommendations for CC patients. The prevalence of CC among Iranian people was between 7 and 8 per 100 000 people, with a significant increase over the last several years.Colon cancer (CC), also known as colorectal cancer (CRC), is the third most commonly diagnosed malignancy and the fourth leading cause of cancer-related deaths worldwide. It has been reported that about 6 to 7 % of CC cases have a genetic origin. Approximately 10 to 15 % of CRC occur in patients where at least one of his/her relatives also had CC. Also, some hereditary syndromes are also effective on the risk of CC including Lynch syndrome and familial adenomatous polyposis syndrome. In addition, some environmental factors such as alcohol consumption, smoking, physical inactivity, high-fat diet and consumption of red and processed meat are also considered as risk factors for CRC. Recent studies reported that change in the expression level of some genes is also a mechanism involved in the effects of these environmental factors(–). Moreover, some people are at higher risk for CC because of their genotype. In other words, the development of CRC is a complex process that involves positive and negative interactions between genes and environmental factors. In the present study, the effects of the interactions between gene polymorphisms and red and processed meat consumption on the risk of CC have been reviewed.In most cases, CC occurs in people aged 50 years or older and the risk of CC recurrence is increased with age. This association has been attributed to several dietary factors, including heterocyclic amines, aromatic hydrocarbons produced during high temperature heating processes, N-nitrosamines that are found in many food products after nitrite addition and processed meat that contains high levels of preservatives. The polymorphisms in some genes involved in the metabolism of these components and risk of CC are discussed below.Many studies have shown that there is a significant association between a red and processed meat-rich diet and CRC. Heterocyclic amines are produced during cooking meat at high temperatures. N-acetyltransferases (NAT) are important enzymes in the metabolic activation of heterocyclic amines, which are found in two forms of NAT1 and NAT2. The rs1495741 polymorphism of NAT2 was strongly related to its activity and the GG, AG and AA genotypes are classified as enzymes with rapid, intermediate and slow activity, respectively. In people with the GG genotype of this polymorphism, there is a strong association between the consumption of red meat and the risk of CRC(–). Another study reported that cooking meat at a high temperature increased the risk of CC in people with NAT2 gene polymorphisms. However, Barrett et al. provide no support for the hypothesis that those with the fast phenotype of NAT2 are at increased risk of CRC.Many studies have examined the enzymes involved in the metabolism of amines and heterocyclic amines and suggested a significant relationship between polymorphisms of these enzymes and risk of CCNAT2 G857A, meat intake more than three times per week increased CRC risk. However, some other studies failed to find any interaction between GG genotype, meat intake and CRC(–). For example, Chan et al. reported that there was no interaction between the amount of meat consumed with NAT1 and NAT2 and the risk of developing CRC. Overall, it can be concluded that NAT2 gene polymorphisms may have a role in CRC risk, especially in people with high meat intake.A study was conducted on 147 CRC patients (seventy-six women and ninety men); the cancer risk in women was found to be lower in the NAT intermediate activity phenotype, but this difference was not found in men. It has also been reported that in people with the GG genotype of COX-1 and COX-2 genes. This polymorphism occurs in the promoter region of the gene, resulting in a possible increase in gene expression with consequent elevation of levels of the COX-2 protein. Individuals who carry the polymorphisms that could affect the expressions of COX-2 are more susceptible to CC. There are two isoforms of the COX enzyme, COX-1 , that produces PG1, and COX-2 (or PTGS2), which produces PG2. The rs20417 (−765G > C) and rs5275 (8473T > C) polymorphisms of COX-2 play an important role in many cancers such as gastric cancer, prostate cancer and CRC. Some studies have also shown that the COX-2 rs1195AA genotype can also play a supportive role in the development of CRC. Makar et al. showed that polymorphism rs20417 (−765G > C) in the COX-2 gene increases the risk of rectal cancer by up to two times higher than others. No significant relationship was reported between COX-1 gene polymorphisms and CRC in this study. In one meta-analysis study, there was a significant relationship between the COX-2 rs20417 polymorphism and the risk of CRC in an Asian population. Andersen et al. suggested that the relationship between the COX-2 rs20417 polymorphism and the risk of CRC is influenced by dietary meat intake and COX-2 rs20417 risk allele carriers were at 8 % increased risk of CRC per 25 g/d higher red meat or processed meat intake. Generally, it can be concluded that COX-2 gene polymorphisms may have a role in CRC risk, especially in people with higher meat intake.Cyclo-oxygenases (COX) play a key role in converting arachidonic acid into prostaglandins. Red meat contains a substantial amount of arachidonic acid and most probably is involved in the inflammatory response and initiation of CC especially in people with a polymorphism in the . CYP2E1 is an enzyme that plays a key role in the metabolism of nitrosamines and other carcinogens. The RsaI polymorphism of CYP2E1  is associated with an increased risk of CRC. The RsaI polymorphism has been shown to affect its transcription level. The variant type of this polymorphic site can enhance transcription and increase the level of CYP2E1 enzymic activity in vitro.CRC is associated with environmental factors such as cigarette smoking, and consuming cooked meats and fish at high temperature. These factors result in the formation of carcinogenic compounds including polycyclic aromatic hydrocarbons, arylamines and heterocyclic amines. The cytochrome P450 (CYP) enzymes are critically important for the metabolism of these carcinogens by N oxidationRsaI C2 allele. On the other hand, a study in China showed that homozygous individuals for the C2 allele were also more likely to develop CRC. Moreover, in some other studies, no relationship was observed between RsaI polymorphisms and the risk of CRC. Interestingly, Morita et al. showed that there is a significant relationship between red meat consumption and an increased risk of CC in the individuals carrying the RsaI C2 allele. However, another study reported that no significant relationship was observed between the the CYP2E1 RsaI polymorphism, red meat consumption and CC.Some studies have also shown that individuals carrying a variant of the C2 allele have lower enzyme activity. In the Hawaiian population, it has been shown that the risk of CC has decreased in subjects carrying the CYP1A2, a member of the cytochrome P450 mixed-function oxidase system, is involved in the metabolism of xenobiotics in the body. Some studies have shown that individuals carrying CYP1A2 polymorphisms are at higher risk of developing rectal cancer but not for CC(–). In a case–control study on CYP1A2 polymorphisms, it was found that there was a significant relationship between the consumption of cooked meat at high temperature in −154A > C polymorphism carriers of CYP1A2 and the risk of CRC. Overall, it is possible that CYP2E1 and CYP1A2 gene polymorphisms may have a role in CRC risk, especially in people with higher meat intake.. Xeroderma pigmentosum (XP) complementation group A (XPA), XP complementation group C (XPC) and XP complementation group D (XPD) are important enzymes in the NER pathway. There is a significant relationship between polymorphisms in XPA, XPC and XPD and a lower capacity of DNA repair. Numerous polymorphisms of NER genes have been identified and these changes individually or in combination may adversely affect NER fidelity, which could contribute to the risk of CRC. Four polymorphisms of these genes including A23G in XPA, Lys939Gln in XPC, and Lys751Gln and Asp312Asn in XPD have been identified that may have a significant relationship with the risk of CC. For example, in a study conducted by Hansen et al., a lower risk of cancer was reported in women with the Lys751Gln polymorphism of XPD. In homozygous individuals with the XPC Lys939Gln polymorphism, the risk of CC was increased by 3·7 times per 100 g/d increased intake of red meat. In the individuals carrying the wild-type allele, meat has no effect on CRC. No significant relationship was observed between other polymorphisms and CC.The nucleotide excision repair (NER) pathway plays an important role in repairing damaged DNA. The NER pathway is a particularly important excision mechanism that removes DNA damage induced by UV light and environmental carcinogensXPD 312Asp and XPD 751Lys risk alleles have a higher chance of developing CRC than those with XPD 312Asn and XPD 751Gln alleles. There is also a statistically significant interaction between Lys939Gln of XPC and A23G of XPA with red meat and processed meat intake and the risk of CC. Overall, it can be concluding that higher meat intake may have a role in CRC risk, especially in people with polymorphisms in genes involved in the NER pathway.Moreover, it was shown that people with a high consumption of red meat and MutS polymorphism. In another study, a significant relationship was observed between processed meat intake, the – polymorphism of the MutS gene and the risk of CC. In general, it can be concluded that MutS polymorphisms may have a role in CRC risk, especially in people with higher processed meat intake.A DNA mismatch repair protein, also known as mutator S (MutS), participates in the DNA mismatch repair system. In a study conducted on the polymorphisms of this gene, it was found that some gene polymorphisms were associated with an increased risk of CC. Processed meat intake could increase CC risk in people with the The presence of SNP associated with the metabolism and function of proteins could play an important role in the effects of red meat consumption on the risk of CC..Several individual SNP have been associated with CC risk. It is plausible that a set of SNP derived from genetic pathways that are critical in colon carcinogenesis could contribute to the cancer risk. We investigated the role of polymorphisms involved in five metabolic pathways that are relevant for the activation or detoxification of carcinogens formed during red meat processing. The polymorphisms investigated in the present study were mostly functional polymorphisms that alter the expression of genes participating in metabolic pathways associated with carcinogenesisNAT2 G857A, COX-2 rs20417, CYP2E1 RsaI, CYP1A2 154A>C, XPC Lys939Gln, XPA A23G and MutS T1036A on the effect of red meat consumption on CRC risk. However, some studies failed to identify an association between red meat consumption and the effect of these polymorphisms on CRC risk. Possible explanations for the discrepancy might include differences in meat variable definitions, and lack of stratification by tumour subsite in these studies. Moreover, other factors including frequency of turning the meat over during the cooking process, meat thickness, cut of meat, use of marinade or thawing meat in the microwave were not considered and may have contributed to these contradictory results.Recent studies demonstrated the modifier role of In conclusion, some gene polymorphisms may have a significant role in CRC risk, especially in people with higher processed meat intake. Increasing the knowledge on nutritional genomics can lead to the finding of new methods to prevent, treat and control of CC. A summary of descriptions of studies is presented in


DAT1 gene in 3′-untranslated region variant number tandem repeat polymorphism and child and adolescent ADHD, whereas in adult ADHD the 9-repeat allele was suggested to confer as risk allele. Interestingly, recent evidence indicated that the long-allele variants (10 repeats and longer) might confer to lower expression of the transporter in comparison to the short-allele. Therefore, we assessed here the association in samples consisting of families with child and adolescent ADHD as well as a case–control sample, using either the 10- versus 9-repeat or the long- versus short-allele approach. Following, we conducted a systematic review and meta-analysis, including family and case–control studies, using the two aforementioned approaches as well as stratifying to age and ethnicity. The first approach (10-repeat) resulted in nominal significant association in child and adolescent ADHD (OR 1.1050 p = 0.0128), that became significant stratifying to European population (OR 1.1301 p = 0.0085). The second approach  resulted in significant association with the whole ADHD population (OR 1.1046 p = 0.0048), followed by significant association for child and adolescent ADHD (OR 1.1602 p = 0.0006) and in Caucasian and in European child and adolescent ADHD . We were not able to confirm the association reported in adults using both approaches. In conclusion, we found further indication for a possible DAT1 gene involvement; however, further studies should be conducted with stringent phenotyping to reduce heterogeneity, a limitation observed in most included studies.Attention-deficit hyperactivity disorder (ADHD) has been postulated to associate with dopaminergic dysfunction, including the dopamine transporter (DAT1). Several meta-analyses showed small but significant association between the 10-repeat allele in the The online version of this article (10.1007/s00702-019-01998-x) contains supplementary material, which is available to authorized users. SLC6A3 / DAT1) in the 3′ untranslated region (UTR), with the 10- and 9-repeat alleles that are most common , characterized by persistent symptoms of inattention, hyperactivity and impulsivity, is one of the most common psychiatric and behavioural disorders in children and adolescents, with more than 5% of the paediatric population affected worldwide, and ADHD often persists into adulthood with a prevalence of 2.5–4.9% in adults  and Parkinson’s disease  inhibited the expression compared to low number of repeats (up to 1-repeat)  carriers conveys a risk for ADHD. In addition, we conducted a systematic review of the literature followed by an updated meta-analysis, including all current available associations with DAT1 3′-UTR VNTR for case–control and family studies in child and adolescent as well as adult ADHD in various ethnicities. To address the possible confounding effects by age of patients, and their ethnicity, a stratified meta-analysis for each variable was conducted.Therefore, in the current case–control and family study, we assessed whether the association between Two hundred and two Caucasian nuclear families (146 families with both parents and 56 families with 1 parent) were recruited and the index patients were investigated in the in- and outpatient units and the day clinics of the Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich. Families were included if at least the index patient fulfilled the diagnostic criteria for ADHD (F90.0 or F90.1) according to ICD-10  were compared to genetically independent 158 Caucasian healthy controls  who were recruited at the Departments of Child and Adolescent Psychiatry of the Universities of Wuerzburg and Zurich. The cases in the case–control study consist of some index from the family study with additional new cases without family members recruited. Informed written consent was obtained in all cases from the participants and their parents. The study was approved by the ethical commissions of both of the involved universities in accordance with the latest version of the Declaration of Helsinki, including an ethical permission granted by the Ethic Committees from Wuerzburg, and the Cantonal Ethic Committee of Zurich (Ref. Nr. KFO 140/03 and KEK-ZH-Nr. 2016-00101).® Green Master Mix (Promega), 9.5 µl water and 1 µl of both primers (forward and reverse 10 µM). The reaction was performed in 0.2 ml PCR 8-tube strips, sealed with individually attached caps (Bio-Rad) in a C1000™ CFX96™ Thermal cycler (Bio-Rad). DNA amplification was achieved under the following conditions: 2 min at 95 °C followed by 30 cycles at 95 °C for 45 s, 67.5 °C for 45 s, 72 °C for 1 min, and a final extension of 5 min at 72 °C. 15 µl of PCR product was loaded into a 3% agarose gel (SeaKem® LE Agarose mixed with 1x TAE buffer) stained with 5 µl HDGreen™ Plus DNA Stain (Intas) per 100 g agarose and run for 90 min at 120 V. A 100 bp BenchTop DNA ladder (Promega) was used to assess the size of the PCR product and set the genotypes according to the expected bands of 316 bp for 6-repeat allele, 396 bp for 8-repeat allele, 436 bp for 9-repeat allele, 476 bp for 10-repeat allele and 516 bp for 11-repeat allele. PCR were run for sample DNA samples in duplicates to ensure reproducibility. In case of ambiguity in the duplicates, genotyping was repeated in a separate run to resolve the discrepancy. No-template controls (NTC) were included in every run to exclude impurities.DNA was isolated either from whole blood collected in ethylenediaminetetraacetic acid (EDTA) tubes using QIAamp DNA Blood Maxi Kit (Qiagen), or from saliva collected in the Oragene DNA collection kit  and isolated as per manufacturer’s protocol. DNA concentrations, A260/A280, and A260/A230 ratios were measured using a spectrophotometer . The study population was genotyped for the DAT1 3′-UTR VNTR polymorphism, using the primers F: 5′-TGTGGTGTAGGGAACGGCCTGAG-3′ and R: 5′-CTTCCTGGAGGTCACGGCTCAAGG-3′. A total volume of 25 µl containing 1 µl DNA sample (50 ng/µl) were mixed with 12.5 µl Promega GoTaqhttp://pngu.mgh.harvard.edu/purcell/plink/ . For the family association study, Mendel errors test (none were found) followed by the transmission disequilibrium test (TDT) was conducted as well as a parent-of-origin analysis.All association studies were run on the PLINK v1.7 [URL: DAT1 3′-UTR VNTR polymorphisms with ADHD. We searched PubMed and Web of Science databases for articles published until December 31, 2018. Literature was searched using the keywords: (DAT* OR SLC6A3 OR “dopamine transporter”) AND (polymorphism* OR VNTR OR “tandem repeat” OR “untranslated region”) AND (ADHD OR “attention hyperactivity”). As a further search manner, we searched the reference sections of the most recently published studies identified in literature search described above, as well as any recently published systematic review articles and meta-analysis, to identify studies that might have been missed. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram  containing data on allele/genotype frequencies in case and control groups and/or odds ratio (OR) and 95% confidence interval (CI) for the OR, (4) samples not duplicative of other studies. In addition to performing a meta-analysis of all studies pooled together, we conducted a subgroup analysis by dividing the studies into those including patients with Caucasian or Asian ancestry to examine the effects of ethnic heterogeneity as well as for adult versus child and adolescent ADHD. If articles only reported allele/genotype frequencies, OR and 95% CI was calculated from allele frequencies using an online OR calculator . Corresponding authors and co-authors were contacted in case of missing data in the selected publications, and were asked to provide the missing information. In case of no respond, articles were excluded (n = 4).A systematic literature search was conducted to include studies that examined associations of http://www.meta-analysis-made-easy.com/)  were used in the software to perform heterogeneity statistics, heterogeneity funnel plots, and synthesis forest plots using inverse variance weighting. The heterogeneity between studies was assessed by Cochran’s Chi square-based Q statistic and the inconsistency index (I2), with p < 0.05 being considered statistically significant. If there was significant (p < 0.05) heterogeneity between studies, we used the random-effects model, otherwise we used the fixed-effects model. The random-effects model considers both between-study and within-study variation, whereas the fixed-effects model considers only within-study variation . In case of p < 0.05 for publication bias, the trim and fill correction was conducted to explore the corrected OR and 95% CI . Furthermore, a significant association was found when assessing according to 10-repeat allele versus 9-repeat allele carriers . Test statistic was based on 211 cases and 155 controls, and genotypes are presented in Table In the case–control study a nominal significant association between DAT1 3′-UTR VNTR long-allele as well as the 10-repeat versus 9-repeat allele yielded no significant association in the Zurich sample . Data from 46 heterozygous parents were included to assess the TDT, and genotypes are presented in Table Family-based association analyses of the DAT1 3′-UTR VNTR with ADHD identified 899 non-duplicated articles . Out of 861 articles, 767 articles were excluded at the title/abstract level. Altogether, 100 articles were read fully, and 34 articles were excluded because various reasons: e.g., missing data, overlapping samples in other publications or not fulfilling the inclusion criteria (Supplementary Table S4). Finally, 61 publications were included in the meta-analysis , including the current study results  with the entire publications, stratified to age of cases (child and adolescent or adult ADHD) and ethnical grouping is presented in Supplementary Tables S2 and S3.The literature search for studies reporting on the association of p = 0.0128), nevertheless the analysis was accompanied with high heterogeneity that was not due to publications bias. Following ethnical stratification, children and adolescent ADHD originating from Europe demonstrated a significant association with 10-repeat allele as risk allele , nevertheless, also here a significant heterogeneity was found. For further detailed stratifications results see Supplementary Table S2.We found no significant association between 10-repeat allele carriers and the entire ADHD population, as well as after stratifying to adult ADHD (Supplementary Tables S2). However, stratification to child and adolescent ADHD resulted in a nominal significant association . Similarly to the 10-repeat analysis, significant heterogeneity was observed with publication bias. Following trim and fill correction the association was still significant with Long-allele as risk allele (OR 1.0614 95% CI 1.0186–1.1060). Following stratification with age, only child and adolescent ADHD kept the significant association , however still with high heterogeneity. In Caucasian child and adolescent ADHD, and in European child and adolescent ADHD, a significant association with the Long-allele was found . In the whole Asian population a nominal significant association was observed, however following trim and fill correction significance was lost (OR 1.0991 95% CI 0.9240–1.3074). The forest and heterogeneity funnel plot for the whole ADHD sample is presented in Fig. DAT1 3′-UTR VNTR gene and child and adolescent ADHD, that reached significance only in the European population; however, this was accompanied by high heterogeneity that was in some cases due to literature bias but in other cases due to heterogeneity in clinical phenotyping, age or ethnicity  for a powerful meta-analysis of the DAT1 3′-UTR VNTR gene variants, and used when needed the random-effects model that incorporate heterogeneity among trials Supplementary material 2 (PDF 438 KB)Supplementary material 3 (PDF 439 KB)


CD40 rs1883832 polymorphism is associated with Graves' disease (GD) risk in different populations. We performed a systematic literature search in China National Knowledge Infrastructure (CNKI), Web of Science, and Pubmed databases to identify case-control association studies on the association between rs1883832 and GD risk. For each study we calculated the odds ratios (OR) and 95 % confidence intervals (CI) assuming dominant, recessive and homozygote models. We then calculated pooled ORs and 95 % CIs. After applying inclusion and exclusion criteria, 17 studies involving 4707 cases and 4215 controls were included in the meta-analysis. The results showed that rs1883832 was associated with GD risk in Asians under dominant , recessive , and homozygote  models. In Caucasians, rs1883832 was associated with GD risk under the dominant model . Besides GD, we evaluated the relation of rs1883832 with Graves' ophthalmopathy (GO), finding that rs1883832 was associated with GO under the dominant model . The findings of our meta-analysis suggest that the CD40 rs1883832 polymorphism is protective against GD and GO in Asians and Caucasians. This meta-analysis aims to evaluate whether the  PTPN22) on chromosome 1p13, and cytotoxic T lymphocyte antigen 4 (CTLA-4) on chromosome 2q33  is the most common cause of hyperthyroidism, affecting approximately 2 % of women and 0.2 % of men . Thyroidüs, 2016).CD40 is a type I transmembrane protein belonging to the tumor necrosis factor (TNF) superfamily. It is expressed on a wide variety of cells including dendritic cells, monocytes, B cells, thyroid follicular cells, and fibroblasts  in the Kozak sequence of the 5' UTR has received much attention. The major allele of this polymorphism enhances the efficiency of CD40 mRNA translation , Web of Science, and Pubmed online databases to identify studies on the association of rs1883832 with GD risk. The search strategy included using the keywords “CD40, gene, polymorphism, association, risk, and Graves' disease”. Searches were not limited by date restrictions. All the identified publications were evaluated for relevance by two independent reviewers, on the basis of their titles and abstracts. The full text of selected studies was obtained and evaluated for eligibility. In addition to database search, the reference lists of all included studies and relevant reviews were carefully scrutinized for additional publications. Final eligibility of studies was decided by consensus. Case-control studies were included if: (1) dealt with the association between the rs1883832 polymorphism and GD risk, (2) provided the raw or summary data necessary to calculate the effect size, and (3) published as full-length articles or letters in peer reviewed journals in Chinese or English. Studies that assessed posttranscriptional factors, such as protein and mRNA expression, rather than genotypic variations were excluded. Studies that used animal populations were excluded.Two reviewers independently extracted data from the included studies using pre-defined criteria and compared data to achieve maximum reliability. The following information was obtained from each publication: first author's name, published year, race of the study populations, sample size, genotyping method, source of controls, age of subjects, female proportion, and genotype frequencies. Disagreements were resolved by discussion and consensus. We did not contact study authors for missing or unclear information because it was not a reliable method. All study methodology conformed to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) criteria .2. Large heterogeneity was typically defined as I2>75 %.All statistical analyses were undertaken using Stata version 12.0 . Odds ratios (OR) with 95 % confidence intervals (CI) were used to assess the size and strength of association between rs1883832 and GD risk. Heterogeneity (true variance of effect size across studies) was assessed using the Cochran Q-test and the Ihttp://ihg.gsf.de/cgi-bin/hw/hwa1.pl). Meta-regression was undertaken to assess the potential sources of heterogeneity identified in the meta-analysis. Publication bias was assessed visually using a funnel plot and tested with the Begg rank correlation test and the Egger linear regression approach.A P-value of >0.10 for the Cochran Q-test was considered to indicate a lack of heterogeneity across studies. All meta-analyses were performed by using either the DerSimonian-Laird random-effects model or the Mantel-Haenszel fixed-effects model, which depended on the heterogeneity . The Z-Details of the search results and study inclusion process are shown in Figure 1CD40 rs1883832 polymorphism and GD risk under dominant , recessive , and homozygote  models. Similar results were found for allele frequency . Stratified analyses according to ethnicity showed that the rs1883832 polymorphism was associated with GD risk in Asians under dominant , recessive , and homozygote  models. In Caucasians, there was an association of this polymorphism with GD under the dominant model . Besides GD, we evaluated the relation of rs1883832 with GO, finding that rs1883832 was associated with GO under the dominant model . Sensitivity analysis was performed excluding studies whose controls significantly departed from HWE  ; the real., 2006; Inoue, al., 2006; Jacobsoal., 2006; Kim, 20al., 2006; Kurylowal., 2006; Luo, 20al., 2006; Makni, al., 2006; Su, 200al., 2006; Sun, 20al., 2006; Wang, 2al., 2006). Signif) Table 2. Meta-reVisual inspection of a funnel plot for asymmetry revealed no obvious indication of publication bias Figure 4. In addiCD40 rs1883832 polymorphism and risk of GD. The results suggested that rs1883832 was protective against GD in both Asians and Caucasians. In addition, our meta-analysis identified a negative association between rs1883832 and GO. To our knowledge, this is the largest and most comprehensive meta-analysis examining the relationship between the 2=57.6 %), but the potential sources of heterogeneity were not evaluated. It was noteworthy that none of the above-mentioned meta-analyses assessed the relationship between rs1883832 and GO, a condition associated with GD that primarily affected the extraocular muscles. In this meta-analysis, we evaluated the association between rs1883832 and GD risk with a total of 4707 GD patients and 4215 controls, having the largest sample size among all meta-analyses on the topic. Besides overall analyses, we conducted subgroup analyses by ethnicity and found a negative association between rs1883832 and GD risk in Asians and Caucasians, respectively. Our study further added to the literature by identifying an association of GO with rs1883832. Concerning the heterogeneity among the included studies, we performed a meta-regression analysis and found publication year and sample size as major contributors to heterogeneity. Several previous meta-analyses were performed on the topic. The meta-analysis by Kurylowicz et al. 2005) evaluat05 evaluaCD40 gene is a member of the TNF receptor family, expressed on the surface of a variety of cells, including B cells, macrophages and thyroid follicular cells. CD40 plays an important role in effector T cell development, B cell differentiation, immunoglobulin production, and isotype switching . Aberraark, 2014). In vival., 1997). It is GO is the most frequently occurring extra-thyroidal manifestation GD, affecting 20 % to 50 % of GD patients . ClinicSome limitations of our study need to be considered. Firstly, the eligible studies in our meta-analysis were mainly performed on Asian and Caucasian subjects. Data from other ethnic groups were unavailable. Future association studies should be conducted in other ethnic groups including Latin Americans and Africans, which would yield a more global and profound picture of the role mediated by rs1883832 in GD pathogenesis. Secondly, the association between rs1883832 and clinical features of GD including age of onset and thyroid autoantibodies were not taken into account in our meta-analysis owing to a lack of published data. It would be valuable to evaluate the relation of rs1883832 with GD features, which could clarify the role of rs1883832 in different subsets of GD patients. Thirdly, due to limitations of the data, gene-gene and gene-environment interactions were not analyzed in the meta-analysis. Future studies evaluating the interactions of rs1883832 with environmental factors and HLA polymorphisms will further expand our knowledge of the underlying genetic mechanisms of GD.CD40 rs1883832 polymorphism on GD in both Asians and Caucasians. Our study also demonstrated a negative association of rs1883832 with GO. Further investigations are warranted to clarify the role of rs1883832 in clinical features of GD and to evaluate gene-gene and gene environment interactions. In conclusion, the available evidence from the present meta-analysis involving 4707 GD patients and 4215 controls suggests a protective effect of the The authors declare that they have no conflict of interest.


We aimed to synthesize the evidence on the relation between different types of potato consumption with risk of all-cause mortality, coronary heart disease (CHD), stroke, type 2 diabetes (T2D), colorectal cancer (CRC), and hypertension.Systematic searches until May 2018 were conducted in PubMed, Scopus, and Web of Science. Random effects meta-analyses comparing extreme categories, linear and non-linear dose–response analyses were conducted.Twenty-eight reports were identified. Only total potato consumption was available for some endpoints which showed no associations with all-cause mortality , CHD , stroke , and CRC  per one daily/serving (150 g/day) increase. Consumption of one daily serving of boiled/baked/mashed-potatoes was not associated with risk of hypertension , but slightly with the risk of T2D . Positive associations for the risk of T2D  and hypertension  were observed for each 150 g/day increase in French-fries consumption. The quality of evidence was rated mostly low .Total potato consumption is not related to risk for many chronic diseases but could pose a small increase in risk for T2D if consumed boiled. A clear risk relation was found between French-fries consumption and risk of T2D and hypertension. For several outcomes, the impact of different preparation procedures could not be assessed.The online version of this article (10.1007/s00394-018-1774-2) contains supplementary material, which is available to authorized users. The present systematic review and meta-analysis was intended to complement previous studies investigating the effects of 12 food groups with respect to risk of all-cause mortality, type 2 diabetes mellitus (T2D), coronary heart disease (CHD), stroke, heart failure, hypertension, and colorectal cancer (CRC). We could show that higher intakes of whole grains, vegetables, fruit, nuts, legumes, dairy, and fish were associated with lower risk of T2D, CHD, stroke, hypertension, and CRC, whereas higher intakes of red and processed meat and SSB were associated with higher risk .When invPotatoes hold a prominent position among the staples in the Western world. According to data of the Food and Agricultural Organization, 377 Mio. tons of potatoes have been produced worldwide in 2016, approximately 80% thereof in Asia (~ 191 Mio. tons) and Europe (118 Mio. tons) [In prospective observational studies, potato consumption was positively associated with the risk of T2D, hypertension or CRC –10. ThisA recent systematic review concluded that the included studies do not provide strong evidence of an association between intake of potatoes and risks of obesity, T2D, and CVD, while French fries may be associated with increased risks of obesity and T2D although confounding may have been present . To the http://www.crd.york.ac.uk/prospero/index.asp, identifier CRD42016037069). Our strategy for the present systematic review is an extension of a pre-defined and published protocol, [The following meta-analysis is part of a systematic review protocol and was registered in PROSPERO  performed the literature search, while another author (GH) reviewed uncertain cases. Consensus was reached through discussion between both authors.As previously described, we included studies with cohort, case–cohort, and nested case–control design, as well as follow-ups of RCTs. Included studies investigated the association between potato intake  on risk of all-cause mortality, CHD, stroke, heart failure, CRC, T2D, and hypertension in adults ≥ 18 years). The definitions of the corresponding chronic diseases were based on the previously published meta-analyses 8 years. .The following data were extracted for each study: name of first author, publication year, country, cohort name, sample size, number of cases, baseline age, sex, duration of follow-up, specification of outcome assessment, specification of type of potato consumed, method of dietary assessment, quantity of potato intake, multivariable effect estimate with corresponding 95% confidence intervals (CIs), and covariates. When the risk estimates for participants were reported only separately for men and women in a study, the risk ratios (RRs) were combined using a fixed effect model.We applied a random effects model  to derivAs described previously, if studies reported only total number of cases or person-years and the exposure was defined in categories, the number of person-years or cases in each category was obtained from the total number of person-years/cases divided by the number of reported categories. We assigned the median or mean intake by quantile to the corresponding risk estimate. If studies reported intakes only as a range by quantile, the midpoint was calculated. In the case of an open-ended intake range, we assumed that the width was the same as the contiguous category. If the exposure was expressed per given unit of energy intake, we used the provided mean energy intake to rescale it.The dose–response was expressed as 150 g/day (weight of a medium potato). If studies reported exposure only in serving size but not specified the amount, 150 g/day as serving was used.Restricted cubic splines for each study with more than three quantiles of exposure were calculated to explore possible nonlinear associations. We used three fixed knots through the total range of the reported intake at 10, 50, and 90% and combined these using multivariate meta-analysis .Q test and the I2 statistic. A value greater than 50% for the I2 statistic was regarded as potentially important statistical heterogeneity [Heterogeneity between studies was evaluated using the ogeneity . If moreAs recommended by the Cochrane Handbook, if 10 or more studies were available , we explTo evaluate the quality of evidence for the association between potato consumption and risk of all-cause mortality, CHD, stroke, heart failure, T2D, CRC, and hypertension we applied our recently developed NutriGrade scoring system (max 10 points) . This toOut of the 556 records which were identified by the literature search, 95 full text articles were assessed in detail .Six prospective cohort studies were included for all-cause mortality –34, seveI2 = 61%, pheterogeneity = 0.03) when comparing extreme categories . Similarly, an increase in overall potato intake by 150 g per day was not associated with risk of all-cause mortality  .Six studies with 26,775 death cases were included in the highest vs. lowest intake category meta-analysis . Five of these studies reported total potato consumption , 33, 34,pnon-linearity = 0.25, n = 4 studies)  Fig. .Fig. 1NoI2 = 0%, pheterogeneity = 0.96) and stroke  . Similarly, an increase in total potato intake by 150 g per day was not associated with risk of CHD  or stroke  .Six studies with 8586 coronary heart disease cases, and six studies with 6902 stroke cases were included in the highest vs. lowest intake category meta-analysis (range of intake 0–212 g/day). All of these studies reported total potato consumption , 39, 40 In additional analyses stratified by sex, follow-up duration, geographic location, number of cases, and dietary assessment method no statistically significant subgroup differences were observed .pnon-linearityp = 0.18, n = 5 studies) and stroke    or in the dose–response meta-analysis  .Eight studies including 3567 incident colorectal cancer cases were included in the meta-analysis comparing extreme intake categories (range of intake 0–221 g/day). Six studies reported total potato consumption –45, one In additional analyses statistically significant subgroup differences for total potato consumption were observed for length of follow-up, and geographic location (ESM Table 4). Stronger positive associations were observed for studies conducted in the Europe, and in studies with long-term follow-up (≥ 10 years).pnon-linearity = 0.69, n = 6 studies). For a daily total potato intake greater than 134 g, the risk of CRC increased by approximately 25% up to ~ 190 g/day  . An increase in total potato intake by 150 g per day was positively associated with risk of T2D  . However, considering only French fries consumption (per 150 g/day) showed a considerable stronger positive association with T2D risk , whereas boiled/baked/mashed potato consumption showed only a slightly increased risk of T2D   .Seven studies with 18,334 incident T2D cases were included in the meta-analysis comparing extreme intake categories (range of intake 0–326 g/day). Four of these seven studies provided additional information for French fries and boiled/baked/mashed potato consumption , 52. We In additional analyses statistically significant subgroup differences for total potato consumption were observed for length of follow-up, geographic location, and dietary assessment (ESM Table 5). Stronger positive associations were observed for studies conducted in the US, in studies with long-term follow-up (≥ 10 years), and in studies applying validated dietary assessment methods.pnon-linearity = 0.14, n = 6 studies). The risk of T2D increased by approximately 51% (predominately due to French fries consumption) with increasing intake of potatoes up to ~ 260 g/day  when comparing extreme categories . An increase in total potato intake by 150 g per day was positively associated with risk of hypertension  . However, only French fries consumption (per 150 g/day) showed a positive association with risk of hypertension , whereas boiled/baked/mashed potato consumption showed no association   .Four studies with 78,484 incident hypertension cases were included in the meta-analysis comparing extreme intake categories (range of intake 0–172 g/day). All of these studies provided additional information about the types of potato consumed (French fries vs. baked/oiled/mashed potatoes). No association between risk of hypertension and total potato intake was observed . The risk of hypertension increased by approximately 13% (predominately due French fries consumption) with increasing intake of potatoes up to ~ 170 g/day .In the present meta-analysis, we observed a positive association between French fries consumption and risk of T2D as well as hypertension following linear dose–response relations, whereas boiled/baked/mashed potato consumption seemed to have negligible influence on these outcomes. For all other outcomes, we were only able to investigate total potato consumption, which resulted in a neutral association. Findings were rated as low quality of evidence  for total potato consumption, and moderate quality of evidence for French fries consumption (T2D and hypertension).According to the literature, the GI represents one mechanism to explain the detrimental associations of French fries consumption . AlthougUsually, potatoes are part of a complex meal , and thiBy applying substitution models it was shown that substituting one serving a day of baked/boiled/mashed potato for non-starchy vegetables was associated with a 7% reduced risk of hypertension in three US studies . MoreoveThe beneficial effects of potatoes on blood pressure due to their high potassium content  is thwarHealthy, Hunger-Free Act of 2010 implemented a restriction of vegetables rich in starch to one portion per day, which was ultimately withdrawn in 2012 [Regardless of components with potential adverse effects on human health, potatoes belong to the most frequently consumed plant-based food groups worldwide. One of the controversies concerns the question of whether they should be regarded as vegetables or not. While recommendations such as “MyPlate” in the US take this stance, potatoes belong to cereals according to the British “EatwellPlate” guidelines . This al in 2012 . Likewis in 2012 .The above-mentioned discrepancies between international recommendations can in part be explained by evidence considering the association of different types of potato intake with health outcomes such as T2D or hypertension , 70, as Hunger-Free Act of 2010 but instead considered as a valuable source for the mineral [Figuratively speaking, potatoes might be regarded as a double-edge sword in this context. Besides their potential detrimental effects described above, potatoes are considered to be easily available suppliers of vital substances such as, e.g. fibre, potassium, vitamin C and secondary plant metabolites. With an average fibre content of approximately 2 g/100 g, potatoes are not among the predominant sources of dietary fibre, however, they become relevant when taking into account the usual amount of consumption as well as the impact of specific preparation procedures which might increase RS/fibre content . Due to  mineral , 74. Des mineral .Several limitations should be acknowledged in the interpretation of the results of the present meta-analysis. Summing up, only a very limited number of prospective observational studies were identified for two out of six outcomes . Moreover, only few studies distinguished between potato preparation methods (i.e. French fries vs. baked/boiled/mashed potatoes) and reported its association with risk of chronic disease. These are clear limitations, since substantial differences exist with regards to energy density of carbohydrate and fat quantity within similar portion sizes across preparation methods . PossiblStrengths of this systematic review are the large number of studies enrolled for meta-analyses and the implementation of different types of meta-analyses to explore highest vs. lowest intake categories as well as linear and non-linear dose–response relationships. In addition, we investigated the quality of evidence using the NutriGrade score. However, there are limitations that should be taken into account when interpreting our findings.Potato consumption in general is not related to risk for many chronic diseases but could pose a small increase in risk for T2D if consumed boiled. A clear risk relation was found between French fries consumption and risk of T2D and hypertension. One of the main limitations in the interpretation of the data is the fact that the impact of different preparation procedures on ingredients exerting these detrimental effects could not be assessed in the studies enrolled in our meta-analyses. Considering the importance of this food group for human nutrition in many parts of the world, potatoes should not be prematurely condemned as an unhealthy part of our diet. Their evaluation and use as a source of valuable nutrients in dietary recommendations should rather take into consideration the progress in the field of cultivation and preparation techniques.Below is the link to the electronic supplementary material.Supplementary material 1 (PDF 526 KB)


Background: Investigations on the association of circulating fetuin-A with all-cause mortality risk in patients with chronic kidney disease (CKD) are conflicting. This meta-analysis aimed to provide a comprehensive estimation of the relationship between fetuin-A and all-cause mortality in CKD patients.Methods: A systematic literature search was performed in PubMed, EMBASE, and The Cochrane Library up until 12 December 2018. Hazard risk (HR) and 95% confidence interval (CI) were pooled using random-effect or fixed-effect model models.Results: A total of 13 studies comprising 5,169 CKD patients were included in the meta-analysis. In a comparison of individuals in the bottom third vs. the top third of baseline fetuin-A levels, the pooled multivariate-adjusted HR for the risk of all-cause mortality was 1.92 (95% CI 1.31–2.80), and the significant association was observed only in dialysis patients, but not non-dialysis patients. When fetuin-A was treated as continuous variables, per 0.1 g/L increase of fetuin-A levels was associated with a 8% lower mortality risk in dialysis patients , but per 0.01 g/L was not. Sensitivity analysis indicated the association was not adjusted by diabetes and inflammation.Conclusion: Lower fetuin-A levels are associated with an increased risk of all-cause mortality independent of diabetes and inflammation in dialysis patients, and there may be a dose-response relationship between them. Chronic kidney disease (CKD) is a major public health concern worldwide, affecting 11 to 13% of global population, and it is associated with adverse clinical events such as cardiovascular disease (CVD) and progression to end-stage renal disease (ESRD)  group  AND  AND . In addition, the references from these relevant articles were manually searched for additional eligible studies.Studies were selected if they met the following criteria: (1) prospective observational studies; (2) study populations should be CKD patients with or without undergoing dialysis; (3) baseline circulating fetuin-A levels as exposure; (4) outcome measures included all-cause mortality; (5) the multivariate-adjusted hazard ratio (HR) or risk ratio (RR) with [95% confidence interval (CI)] was provided. Studies only reporting unadjusted risk estimates were excluded.Two investigators independently selected studies and extracted the following information: first author's name, publication year, study origin, type of patients, sample size, mean age or age range, percentage of male patients, measurements of risks, number of death event, the most fully adjusted risk estimate, follow-up duration, and adjustment for potential cofounders in multivariate model. Any disagreement in opinion in the data extraction was resolved by discussion among all researchers. For the methodological quality evaluation, Newcastle-Ottawa Scale (NOS) for cohort studies was used for these included studies Stang, . The NOSx2 test with significance set at <0.10, and quantified by the I2 index . The included studies reported RR, which were assumed to approximate HR and were combined directly. Individual studies reported the multivariate-adjusted risk estimate in this meta-analysis were displayed in different variable types . In order to provide a consistent comparison to meta-analysis, we used previously described methods to transform some of these types  to a measure of association corresponding to the bottom vs. the top third of the baseline fetuin-A concentration . A random effect model was selected because there was significant heterogeneity among the included studies   .p = 0.001); however, per 0.01 g/L increase of fetuin-A levels [two studies   . Fixed-eI2 = 0) and non-dialysis patients (I2 = 0) stratified by the follow-up period and type of patients, considerable heterogeneity was still found in other subgroups .Subgroup analysis was performed on all-cause mortality by the study region, sample sizes, duration of follow-up and type of patients in nine studies in which the association was presented as the bottom vs. the top third. As shown in p = 0.001).Due to the fact that the small number of studies were included in measurements of per 0.1 g/L and per 0.01 g/L increase of fetuin-A levels, publication bias and sensitivity analysis were performed only in 9 studies in which the association was presented as extreme thirds. Publication bias was assessed first by a visual inspection of funnel plot, which showed asymmetrical . Egger'sIn the sensitivity analysis, pooled HR varied within 1.65–2.30, and low 95% CI varied within 1.16–1.45 when anyone study was omitted in 9 studies . In addiThis is the first meta-analysis reporting pooled data on the association between circulating fetuin-A levels and all-cause mortality in CKD patients. The data suggest that CKD patients with fetuin-A levels in the bottom third had a 92% greater risk of all-cause mortality compared with those in the top third. In subgroup analysis, the significant association between low fetuin-A levels and higher risk of mortality was observed only in dialysis patients, but not non-dialysis patients. Furthermore, we found that per 0.1 g/L increase of fetuin-A levels was associated with a 8% lower risk of all-cause mortality in dialysis patients, but per 0.01 g/L was not. These findings suggest that lower levels of fetuin-A were a significant predictor of all-cause death in dialysis patients, and there may be a dose-response relationship between them.In this meta-analysis, in order to determine the independent association between fetuin-A and all-cause mortality, we only included studies that reported the multivariate-adjusted risk estimates, but not unadjusted ones. Circulating fetuin-A levels can be influenced by many factors such as insulin resistance, glucolipid metabolism and systemic inflammation. There are interactions between fetuin-A and free fatty acid which induces inflammatory signaling and insulin resistance, and subsequently leads to increased risk of type 2 diabetes (T2DM) (Pal et al., in vitro studies suggest that fetuin-A can enhance phagocytosis of apoptotic cells and macropinocytosis by human macrophages (Jersmann et al., The association between lower fetuin-A levels and poor prognosis in CKD patients could be explained by several possible mechanisms. First, fetuin-A can inhibit the deposition of calcium phosphate by forming soluble mineral complexes, which can be called as fetuin-mineral complex (Herrmann et al., Several limitations of this meta-analysis should be of concern. First, the accumulating evidence showed that individuals with CKD are at higher risk of cardiovascular mortality, and several studies included this meta-analysis also analyzed the relationship of circulating fetuin-A levels with cardiovascular mortality (Stenvinkel et al., In conclusion, this meta-analysis demonstrated that lower fetuin-A levels are associated with an increased risk of all-cause mortality independent of diabetes and inflammation in dialysis patients, and there may be a dose-response relationship between them. Further large-scale studies are required to confirm these findings.All datasets generated for this study are included in the manuscript and/or the supplementary files.ZZ contributed to statistical analyses and paper writing. YJ and HC contributed to literature search, data extraction, and quality assessment. HJ contributed to editing and revision of the manuscript. MS designed the study and performed data interpretation. All authors have approved the final version of this paper that was uploaded to the journal website.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Background: We obtained conflicting results regarding the relationship between the genetic role of the rs1138272 C/T polymorphism of the GSTP1 (Glutathione S-Transferase pi) gene and the risk of various cancers.Methods: Using the presently available data, a meta-analysis was conducted to comprehensively evaluate the genetic relationship between the GSTP1 rs1138272 polymorphism and cancer susceptibility.Results: A total of 43 studies including 15,688 cases and 17,143 controls were recruited into our quantitative synthesis. In the overall population, we observed an increased risk of overall cancer cases, compared with unrelated controls, in the genetic models of allele T vs. allele C , carrier T vs. carrier C , TT vs. CC , TT vs. CC+CT , and CT+TT vs. CC . We detected similar positive results within the Asian population. Additionally, there was a significant increase in the incidence of cancer for Africans under all genetic models . When targeting the Caucasian population, we detected a positive association with the TT vs. CC and TT vs. CC+CT models in the “Colorectal cancer”  and “Head and neck cancer”  subgroups. For the “Lung cancer” subgroup, we observed a slightly increased risk in Caucasians under the models of allele T vs. allele C, carrier T vs. carrier C, CT vs. CC, and CT+TT vs. CC .Conclusion: The TT genotype of the GSTP1 rs1138272 polymorphism is likely related to the susceptibility to overall cancer in the Asian and African populations and, specifically, “Colorectal” and “Head and neck” cancers in the Caucasian population. In addition, the CT genotype of the GSTP1 rs1138272 polymorphism may be linked to the risk of lung cancer in Caucasians. Additional evidence is required to confirm this conclusion. GSTP1 gene is located on chromosome 11 (11q13.2) (S-Transferase pi) protein participates in the drug resistance process of cancer cells  and rs1138272 , may be related to the occurrence and development of certain diseases  , and theer cells . Two comdiseases . For insanalysis . There hpulation , but notpulation  or bladdpulation . To the GSTP1 rs1138272 C/T polymorphism on the risk of overall cancer. In view of the publication of new relevant articles in the last 5 years, we performed an updated meta-analysis to gain insight into the genetic association between the rs1138272 C/T polymorphism of the GSTP1 gene and the risk of cancer. Altogether, 43 eligible case-control studies were recruited into our statistical analysis.Five online databases extending until September 2018, including PubMed, Embase, Cochrane, Scopus, and WOS (web of science), were utilized for the article identification. Referring Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)  were conGSTP1 rs1138272 in the cases/controls were also removed. The basic information was then collected and summarized, and P-HWE  was calculated. The quality appraisal of each study was also performed using the Newcastle-Ottawa Scale (NOS) system. Articles with P-HWE > 0.05 for the controls and an NOS score > = 5 were included. Eligible case-control studies were finally considered.First, duplicate articles or articles with overlapping data were removed. In addition, review articles, meta-analyses, meeting abstracts and case reports were excluded. Articles that lacked normal control data or the complete genotype data on the CC, CT, TT status of P-heterogeneity of Cochran’s Q statistic was larger than 0.1 or the I2 value was less than 50%. When those criteria were not met, a random effects model was used in the DerSimonian and Laird statistics of association test. For the assessment of the pooled effect size, we obtained the odds ratio (OR), 95% confidence interval (CI) and P-Association  from each meta-analysis and subsequent subgroup analysis by ethnicity, control source, or cancer type.A fixed-effects model was applied in the Mantel–Haenszel statistics of association test when the We used the Begg’s and Egger’s tests to assess the potential publication bias when the number of enrolled case-control studies was larger than 10. We also performed a sensitivity analysis to evaluate the data stability and possible sources of heterogeneity. The STATA software  was used to analyze the following genetic models in the association test, Begg’s test, Egger’s test, and sensitivity analysis: the allele model , homozygote model (TT vs. CC), heterozygote model (CT vs. CC), dominant model (CT+TT vs. CC), recessive model (TT vs. CC+CT), and carrier model (carrier T vs. carrier C).in vitro data on cell lines; 792 articles focusing on other diseases, other genes or other variants of the GSTP1 gene; and 111 articles containing data on methylation or gene expression. Next, we assessed the eligibility of the remaining 96 full-text articles. An additional 56 articles were excluded, including 56 articles with unavailable data on the genotype frequency of CC, CT, and TT within GSTP1 rs1138272, and 4 articles in which the data were not in HWE. After a quality evaluation, 40 articles , carrier T vs. carrier C , TT vs. CC , TT vs. CC+CT , and CT+TT vs. CC . Nevertheless, no significant effect on cancer risk was observed for the model of CT vs. CC (Table P-association = 0.106). Supplementary Figures GSTP1 rs1138272 polymorphism may be associated with an increased susceptibility to cancer.First, we analyzed the relationship between the P-association < 0.05, OR > 1). As shown in Supplementary Table P-association = 0.006, OR = 1.45) and TT vs. CC+CT  models. Figures P-association < 0.05, OR > 1), but this was not the case for the “Caucasian” (Table P-association > or = 0.05). In addition, no significant association was found based on cancer type under most of the genetic models, except for the TT vs. CC  and TT vs. CC+CT  models of the “Head and neck cancer” subgroup. Supplementary Figure GSTP1 gene appears to be correlated with an increased risk of cancer in the Asian and African populations. Moreover, the TT genotype of GSTP1 rs1138272 may be associated with the risk of head and neck cancer in the overall population.Next, we performed three subgroup analyses based upon ethnicity Table , controln” Table  and “Hosn” Table  subgroupP-association > 0.05), there was a positive association between GSTP1 rs1138272 and the risk of colorectal cancer in the Caucasian population for the models of TT vs. CC  and TT vs. CC+CT . With regard to “Lung cancer,” we observed a slightly increased risk in the Caucasian population under the models of allele T vs. allele C , carrier T vs. carrier C , CT vs. CC , and CT+TT vs. CC . Further, to eliminate the effects of the HB controls in the results of the Caucasian population, we also performed another subgroup analysis based upon cancer type using the Caucasian cases and population-based negative controls. Similar results were detected for colorectal and lung cancer  or the allele (P-Egger = 0.013), carrier (P-Egger = 0.035), homozygote (P-Egger = 0.013), recessive (P-Egger = 0.013), and dominant (P-Egger = 0.046) models in the Egger’s test. For the analysis targeting the Caucasian population . However, this slight publication bias only existed for the homozygote (P-Egger = 0.049) and recessive (P-Egger = 0.044) models using the Caucasian cases and population-based negative controls in the Egger’s test  null genotype was reported to be associated with the risk of colon or rectal cancer in the Indian population (GSTP1 polymorphism combined with variants of other genes in specific cancer types. The factors, such as the age of onset, sex, lifestyle, environmental exposure, cancer source, linkage disequilibrium, synergistic interaction between genes, etiologies, relapses, and other patient clinical characterizations should be considered carefully when more data is available.Considering the role of possible linkage disequilibrium in the genetic susceptibility to different cancers, we tried to extract the data of pulation . The limGSTP1 rs1138272 polymorphism is associated with the susceptibility to overall cancer in the Asian and African populations and, moreover, this polymorphism may be linked to the risk of colorectal, lung or head and neck cancers in the Caucasian population. More eligible case-control studies containing cases with distinct cancers in various ethnic backgrounds are necessary for a more precise and relatively objective estimation.Above all, our pooled analysis consisting of the currently available eligible case-control studies demonstrated that the FD, J-PL, and YZ were conducted by database searching and screening process. FD, G-HQ, and Z-CS was performed by statistical analysis. FD and J-PL wrote the manuscript. Y-HY reviewed the manuscript. All authors approved the final version of the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


The aim of this study was to evaluate the correlation between endothelial nitric oxide synthase (eNOS) polymorphism (−786T>C) and migraine susceptibility in a meta-analysis.I2 index and quality assessment was performed using the Newcastle–Ottawa scale.A literature search was performed for case–control studies from inception to July 30, 2018 focusing on eNOS polymorphism (−786T>C) and risk of migraine. From 454 full-text articles, 6 were included in this study. Heterogeneity was assessed with the P = .17; I2 = 18%). However, subgroup analysis showed CC variant increase the risk for migraine compared with TT+ TC genotypes in Caucasian populations , which could not be observed in non-Caucasian populations . There was no significant difference for other genotypes and alleles between patients with migraine and healthy controls .CC genotype was not related to higher susceptibility of migraine compared with TT+ TC genotypes with significant difference (fixed effects model; OR = 1.27; 95% CI = 0.90–1.80; This meta-analysis indicated that CC variant increases the risk for migraine compared with TT + TC genotypes in Caucasian populations. Migraine is clinically diagnosed according to the criteria set out by the International Headache Society (IHS). Migraine often begins with premonitory symptoms hours or days before the onset of pain. The most common premonitory symptoms include fatigue, impaired concentration, and neck stiffness. Furthermore, other psychological , arousal (drowsiness), neurological (photophobia), and cranial parasympathetic symptoms (lacrimation), and general symptoms  can occur before the onset of pain. The IHS classifies migraine as migraine with aura (MA), representing about one-third of all migraine, or migraine without aura (MO) that accounts for approximately two-thirds of all migraine in the population.,4,5 Although researches have been performed for many years, the complex pathogenetic mechanisms of migraine still remain unclear. Migraine is considered to be as a result of combination of environmental and genetic aspects.Migraine is a chronic paroxysmal neurological disorder characterized by attacks of moderate or severe headache and reversible neurological and systemic symptoms that affects approximately 12% to 16% of the population. It exerts a variety of physiological effects such as regulating blood pressure via smooth muscle relaxation, and functioning as a neurotransmitter. NO in the migraine pathogenesis has been reported in several studies.,9 Polymorphism of NOS could affect production of NO, which may be connected with migraine. The associations between a single nucleotide polymorphism (SNP) of NOS and migraine were widely studied.–20 Although nNOS is predominately expressed in neurons of the central and peripheral nervous systems, studies evaluating the association between nNOS polymorphism and migraine were limited. There was no marked association between nNOS polymorphisms  and migraine susceptibility.,11 Conversely, a series of studies reporting the relationships between SNPs of iNOS, eNOS genes, and risk of migraine.–20 There was no association between bi-allelic tetranucleotide polymorphism of iNOS and migraine. The 2087G>A (rs2297518) and the −1026C>A (rs2779249) polymorphisms in the iNOS gene affect the susceptibility to MA when their effects are combined within haplotypes, whereas the 2087G>A affects the susceptibility to aura in migraine patients. A significant interaction between iNOS 2087G>A and eNOS 2512+242G>A/C (rs743506) polymorphisms in migraine patients compared to control group, suggesting that this combination affect migraine susceptibility. Three clinically relevant polymorphisms of eNOS have been studied: SNP in the promoter region , an SNP in exon 7 , and the variable number of tandem repeats (VNTR) in intron 4.,22 Borroni et al reported that eNOS (+894G>T) polymorphism was an independent risk for MA. However, a later study could not verify the conclusion. A recent meta-analysis indicated that “T” allele of the eNOS +894G > T variant increased the risk of migraine among non-Caucasians. The substitution of thymine by cytosine in the 5′ promoter region at nucleotide—786 (−786T>C) results in a significant reduction in eNOS gene promoter activity and in decreased basal NO production. Similarly, there are some controversies for the connection between eNOS polymorphism (−786T>C) and migraine risk.,18–20 This meta-analysis was carried out to evaluate the relationship between eNOS (−786T>C) polymorphism and migraine susceptibility.Nitric oxide (NO) is a signaling molecule with a short half-life, which is synthesized from L-arginine by 3 isozymes of nitric oxide synthase (NOS), including neuronal NOS (nNOS), endothelial NOS (eNOS), and inducible NOS (iNOS).22.1Two authors independently performed literature search for published studies from inception to July 30, 2018 using PubMed, Cochrane Database, EMBASE, Web of science, Google scholar, and China National Knowledge Infrastructure (CNKI). The keywords used were “nitric oxide synthase,” or “NOS,” or “endothelial nitric oxide synthase,” or “NOS3,” or “eNOS” and “migraine,” or “migraine disorder.” The titles and abstracts of the resulting articles were examined and unrelated articles were excluded. If an article was selected for inclusion, the references were reviewed for additional studies. This study was approved by the ethics committee of the First Hospital of Jilin University.2.2,5,14,19 or whose health was established by medical diagnosis.,20 Studies were excluded if one of the following existed: studies with insufficient genotyping data of patients or control group; case reports; review articles; experiment researches; case-only studies. Disagreements between the 2 reviewers regarding inclusion of a study were resolved through consensus.An article was relevant if it reported original data from case–control study, regardless of language, investigating the correlations between eNOS polymorphism (−786T>C) and migraine susceptibility. Controls were healthy individuals without migraine randomly selected from general populations after excluding those with underlying diseases ,2.3Two independent reviewers extracted the data and assessed the quality of each study using the Newcastle–Ottawa scale (NOS). In this scale 9 points represent the highest quality. In case of disagreements, the original article was evaluated by a third reviewer.2.4I2 statistic: values of 25%, 50%, and 75% represent mild, moderate, and severe heterogeneity, respectively. Based on results of the heterogeneity test, a fixed effect model was used if P > .10, while a random effects model was performed if P ≤ 0.10. Begg's funnel test and Egger's test were applied to evaluate publication bias across studies with Stata (version 12.0). A P < .05 was considered statistically significant.RevMan 5.2 (Cochrane database) was used to analyze the data. The results were reported as odds ratios (OR) with 95% confidence intervals (CI). Heterogeneity between studies was assessed by using the 33.1We followed the PRISMA  statement for reporting our results. Six studies of full-text articles were selected for inclusion in this meta-analysis. Our selection process for studies included in the analysis was shown in Figure 3.2,19 2 from Turkey,,5 1 from the United Kingdom, and the last one was from Iran. A total of 763 patients with migraine and 560 healthy controls were included in this meta-analysis. The frequencies of genotypes and alleles were summarized in Table The characteristics of the included studies, which were published between 2005 and 2017, were presented in Table 3.3P = .12; I2 = 86%). CC genotype was not associated with higher susceptibility of migraine compared with TT+ TC genotypes with significant difference  . However, subgroup analysis showed CC variant increase the risk for migraine compared with TT+ TC genotypes in Caucasian populations , which could not be observed in non-Caucasian patients   and C allele  did not increase the risk of migraine compared with TT genotype and T allele, respectively.Considering heterogeneity existed in this study, we used Galbraith plots to explore the heterogeneity sources Fig. . Low New3.5P = .452 and 0.317, respectively)  Fig. .4 NO activates soluble guanylate cyclase and subsequently increases cGMP. cGMP can induce gene expression via the induction of transcription factors such as mitogen activated protein (MAP) kinases or NF-κB. Although the aetiology and pathogenesis of migraine remain unclear, NO is believed to play a key role in migraine pathogenesis. Migraine was initiated by NO donors, glyceryl trinitrate (GTN), or isosorbide dinitrate, which indicated that NO may participate in the pathological process of migraine.,25 GTN did initiate migraine headaches but not the aura in migraineurs with aura in most studies. This indicated that NO is involved in the pain mechanism in both types of migraines but not in the initiation of the aura. Further study demonstrated that not NO itself but the elevation of cGMP by NO or other mediators is necessary to induce migraine. Inhibition of NOS in spontaneous migraine attacks leads to the attenuation of symptoms in two-thirds of the patients. Thus, NO seems not only be involved in the initiation of migraine attacks but also in the maintenance of these attacks. Calcitonin gene related peptide (CGRP) is a key player in migraine pathophysiology. CGRP levels were elevated following GTN-induced migraine. Pretreatment of trigeminal ganglia cultures with NO donors was also found to increase CGRP release in response to both depolarization and inflammatory mediators, which may have occurred due to NO donors increasing CGRP promoter activity.,31 While NO donors have some functions independent of CGRP, their function in migraine may strongly relate to promoting CGRP production and release, adding to the CGRP-influenced pathways in migraine.NO regulates a host of physiological functions, including vascular tone, pain sensation, neurotransmission, and as an immune defence mechanism.NO was synthesized by NOS from L-arginine. The activity of NOS has an important impact on the production of NO, and polymorphism of NOS gene leads to variant activity of NOS. In this study, we carried out a meta-analysis to evaluate the correlation of eNOS polymorphism (−786T>C) and migraine risk. The overall results did not indicate associations between eNOS polymorphism and migraine. However, subgroup analysis showed CC variant increase the risk for migraine compared with TT + TC genotypes in Caucasian populations.P = .58; I2 = 0%). Second, using Galbraith plots, source of heterogeneity was identified. After removal of studies with significant heterogeneity, fixed model showed that both CC + CT genotypes and C allele did not increase migraine susceptibility compared with TT genotype and T allele, respectively.When compared between CC + TC genotypes and TT genotype, between T allele and C allele, significant heterogeneity existed. Random effects model indicated that there was no significant difference between patients and healthy controls. First, we carried out subgroup analysis by populations. Lack of association was observed between eNOS polymorphism and migraine susceptibility in non-Caucasians . Although statistical significance could not be acquired with current studies, a larger sample may reach a positive result. Hence, further study is still needed.Our study has several strengths. First, this is the largest study to date evaluating the correlation between eNOS −786T>C polymorphism and risk of migraine. Second, patients and controls of different genetic backgrounds made it possible to analyze the associations in different populations. However, our study also has several limitations. First, due to apparent heterogeneity across studies in some cases, the findings from our study should be dealt with some caution. Second, we did not include academic dissertations and conference papers, so there may have been bias in provision of data. Third, there are other factors that affect the incidence of migraine, for example, gender,Although the association of eNOS −786T>C polymorphism and migraine susceptibility were reported in previous studies. This meta-analysis indicated that CC variant increase the risk for migraine compared with TT+ TC genotypes in Caucasian populations. More studies are still needed to verify such conclusion.We thank the Department of Geriatric Medicine, the First Hospital of Jilin University, for their assistance in this work. This work was supported by the Program from Health commission of Jilin Province (2014Q030).DH, WZH, DB, HYN, and ZHY conceived the study. DH, WZH, DB, HYN, and ZHY designed the study and analyzed the data. DH, DB, and ZHY wrote this manuscript. All authors discussed and revised the manuscript before submission.Conceptualization: Han Dong.Data curation: Han Dong, Bin Dong, Ya Nan Hu, Hui Ying Zhao.Formal analysis: Han Dong, Zhi Hao Wang, Bin Dong.Funding acquisition: Han Dong.Investigation: Han Dong, Bin Dong, Ya Nan Hu, Hui Ying Zhao.Methodology: Han Dong, Zhi Hao Wang, Bin Dong, Ya Nan Hu, Hui Ying Zhao.Resources: Zhi Hao Wang.Software: Han Dong, Zhi Hao Wang, Bin Dong.Supervision: Hui Ying Zhao.Validation: Ya Nan Hu.Writing – original draft: Han Dong.Writing – review & editing: Han Dong.


Background: Previous case–control studies have suggested that apurinic/apyrimidinic endonuclease 1 (APE1) rs1760944 T>G polymorphism may be associated with cancer risk. Here, we carried out an updated meta-analysis to focus on the correlation between APE1 rs1760944 T>G locus and the risk of cancer.Methods: We used the crude odds ratios (ORs) with their 95% confidence intervals (CIs) to evaluate the possible relationship between the APE1 rs1760944 T>G polymorphism and cancer risk. Heterogeneity, publication bias and sensitivity analysis were also harnessed to check the potential bias of the present study.Results: Twenty-three independent studies involving 10166 cancer cases and 11598 controls were eligible for this pooled analysis. We found that APE1 rs1760944 T>G polymorphism decreased the risk of cancer in four genetic models . Results of subgroup analyses also demonstrated that this single-nucleotide polymorphism (SNP) modified the risk among lung cancer, breast cancer, osteosarcoma, and Asians. Evidence of publication bias was found in the present study. When we treated the publication bias with ‘trim-and-fill’ method, the adjusted ORs and CIs were not significantly changed.Conclusion: In conclusion, current evidence highlights that the APE1 rs1760944 T>G polymorphism is a protective factor for cancer susceptibility. In the future, case–control studies with detailed risk factors are needed to confirm or refute our findings. The incidence and mortality of cancer is increasing worldwide . It was Apurinic/apyrimidinic endonuclease 1 (APE1) is a multifunctional protein which plays an important role in the pathway of base excision repair (BER). APE1 plays a pivotal role in tumor cells involving DNA damage response and regulating transcription factor activation . The obsAPE1 gene is approximately 3 kb in length and is located on chromosome 14q11.2 [APE1 gene are established (https://www.ncbi.nlm.nih.gov/snp/?term=APE1). APE1 rs1760944 (−656T>G) is a promoter locus and has been widely explored. Some functional studies indicated that the APE1 rs1760944 T>G single-nucleotide polymorphism (SNP) might decrease APE1 mRNA and protein expression levels [APE1 rs1760944 T>G polymorphism with the development of cancer. Individuals with APE1 rs1760944 GG variant might reduce 46% glioblastoma risk than those who carried APE1 rs1760944 TT variant [APE1 rs1760944 T>G polymorphism and a decreased susceptibility of lung cancer was also found by Lu et al. [APE1 rs1760944 GT/GG variants might have a better survival than others with APE1 rs1760944 TT genotype [APE1 rs1760944 T>G polymorphism and the risk of other cancers. The findings were more confusing. The aim of the present study was to carry out a meta-analysis to evaluate whether this SNP was associated with the risk of cancer. 14q11.2 . A numben levels ,24. Many variant . The relgenotype . But thegenotype ,28. ReceAPE1 rs1760944 T>G locus with the risk of cancer from the inception up to 17 March 2019. The search strategy was: (polymorphism OR SNP) and (apurinic/apyrimidinic endonuclease 1 or APE1 or APE-1) and (cancer OR carcinoma). In the current study, publications written in English or Chinese were eligible. Moreover, the references of the included studies, comments, meta-analyses and reviews were manually retrospected to recruit the potential literatures.PubMed and Embase databases were exhaustively searched for relevant publications which studied the relationship of APE1 rs1760944 T>G locus and the risk of cancer; (2) the diagnosis of cases was confirmed by pathological examination; (3) the frequencies of alleles or genotypes were presented; (4) the paper was written in English or Chinese.For eligibility, publications were required to meet the following inclusion criteria: (1) case–control studies investigating the relationship between the APE1 rs1760944 T>G polymorphism; and (3) meta-analyses/reviews, comments and letters focusing on the relationships between the APE1 rs1760944 T>G locus and cancer risk.Studies were excluded based on the major exclusion criteria: (1) not case–control design; (2) studies did not provide genotyping data on Two authors (Guowen Ding and Yu Chen) reviewed each eligible study independently. They extracted the following terms from case–control studies, including the first author name, publishing year, country where the study was carried out, ethnicity, the source of control, cancer type, numbers of included cases and controls in each case–control study, genotyping data, the method of polymerase chain reaction, statistical method and evidence of Hardy–Weinberg equilibrium (HWE) evaluation in control group. If the extracted data had any dispute, authors settled these issues following a detailed discussion among all reviewers.2 test (http://ihg.gsf.de/cgi-bin/hw/hwa1.pl). We calculated crude odds ratios (ORs) and 95% confidence intervals (CIs) to evaluate the correlation of APE1 rs1760944 T>G polymorphism and cancer risk. The following four genetic models were used, including homozygote model (GG vs. TT), dominant model (GG/TG vs. TT), recessive model (GG vs. TT/TG) and allele model (G vs. T). Cochran’s Q-statistic and 2I test were used to check the heterogeneity among the included studies. The random-effect model was harnessed when 2I > 50% or P<0.10 [P-value (two-sided) <0.05 was defined as statistically significant.HWE in controls was assessed by an online Pearson’s χr P<0.10 ; otherwir P<0.10 . SubgrouAPE1 rs1760944 T>G polymorphism with cancer risk [2 test was used to calculate the pooled ORs and CIs. The detailed characteristics of the included case–control studies are shown in cer risk ,31–47. Acer risk ,31–33, tcer risk , three icer risk , three icer risk ,41, two cer risk , two invcer risk ,43 and fcer risk , renal ccer risk , prostatcer risk  and ovarAPE1 rs1760944 T>G polymorphism with the susceptibility of cancer [APE1 rs1760944 T>G polymorphism conferred statistical evidence of the relationship between APE1 rs1760944 T>G locus and a decreased risk of cancer , breast cancer , and osteosarcoma .When we conducted subgroup analyses according to cancer type, the results suggested that P=0.055, Egger’s test P=0.013; GG vs. TT: Begg’s test P=0.037, Egger’s test P=0.080; GG/TG vs. TT: Begg’s test P=0.051, Egger’s test P=0.016; GG vs. TT/TG: Begg’s test P=0.055, Egger’s test P=0.174; In the present study, Begg’s and Egger’s tests were used to assess the potential bias among the eligible studies. Evidence of bias was found in the present study . Thus, we subsequently performed subgroup analyses. The findings suggested that the APE1 rs1760944 T>G polymorphism might be a protective effect on the development of cancer in Asians only, but not Caucasians. In the present study, one case–control study was incongruent with HWE [APE1 rs1760944 T>G polymorphism still significantly decreased the risk of some type of cancers.Rs1760944 T>G is a promoter SNP in the f cancer ,42,44,46cer risk ,43,45,47with HWE . When weAPE1 rs1760944 G allele decreased APE1 mRNA and protein expression levels [APE1 rs1760944 G allele was associated with a decreased level of APE1 mRNA by reducing the binding affinity of some transcription factors. Although the pathway of the relationship between APE1 rs1760944 T>G and cancer risk has been not confirmed, it is speculated that this SNP may alter the susceptibility of cancer through the mechanism mentioned above. All observations and speculations should be verified with new molecular studies.It was found that inhibition of APE1 activity might reduce cell growth of ovarian cancer  and pancn levels ,24. AddiAPE1 rs1760944 T>G polymorphism was included to assess the association with the risk of cancer; other functional loci in APE1 gene should not been ignored.Some limitations of the current analysis should be noted. First, in this meta-analysis, only published literature was eligible and included, and some presumable unpublished studies might be neglected and discarded. Second, heterogeneity and publication bias were apparent, which could distort the pooled results. Our findings should be interpreted with cautions. Third, for lack of sufficient data , we only conducted a crude assessment. Finally, only APE1 rs1760944 T>G polymorphism may play a protective role in the development of cancer. Further studies in different race are needed to confirm or refute our findings.In summary, this updated meta-analysis highlights that the