Vitamin D receptor (VDR) gene polymorphisms are possibly involved in the development of type 1 diabetes mellitus (T1DM). However, the results to date have been inconclusive. We performed a meta-analysis to examine the association between 2 polymorphisms (FokI and BsmI) of the VDR gene and T1DM in the Asian population.Literature was retrieved from PubMed, Web of Science, CBM, Embase and Chinese databases. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using a random or fixed effect model.In total, 20 papers  were included. In contrast to the FokI polymorphism, the BsmI polymorphism was associated with an increased risk of T1DM in the Asian population . Upon stratification by regional geography, an increased risk of T1DM in association with the BsmI polymorphism was observed in the East Asian population , whereas the FokI polymorphism was associated with an increased risk of T1DM in the West Asian population .Our meta-analysis suggests that the BsmI polymorphism may be a risk factor for susceptibility to T1DM in the East Asian population, and the FokI polymorphism is associated with an increased risk of T1DM in the West Asian population. However, because the study size was limited, further studies are essential to confirm our results. Type 1 diabetes mellitus (T1DM) is a T-cell-mediated autoimmune disease, resulting from autoimmune destruction of β-cells of the pancreas. Although the complicated mechanisms involved in T1DM remain unclear, it is well known that T1DM is caused by complex interactions between many genetic and environmental factors. So far, several gene polymorphisms have been demonstrated to be associated with the risks of T1DM, including the human lymphocyte antigen (HLA) gene, the regulatory region of the insulin gene and the interleukin-1 receptor type 1 (IL1R1) gene, cytotoxic T lymphocyte associated-4 (CTLA-4) gene and the vitamin D receptor (VDR) gene. Among these susceptibility genes, the VDR gene is one of the most widely studied and increasing evidence suggests that vitamin D and its receptor are possibly related to T-cell-mediated autoimmune disease and influence susceptibility to T1DM.The VDR is found in almost all cells of the immune system, especially the antigen-presenting cells (macrophages and dendritic cells) and activated T lymphocytes. It is increasing acknowledged that vitamin D is a potent modulator of the immune system and is involved in regulating cell proliferation and differentiation, lymphocyte activation and cytokine production The human VDR gene is located on chromosome 12q12–q14. It has at least 5 promoter regions, 8 protein-coding exons and 6 untranslated exons, which are alternatively spliced into FokI (in exon 2), BsmI and ApaI (both in intron 8) and TaqI (in exon 9). In the past decades, a series of studies have investigated the association between FokI (rs10735810) and BsmI (rs1544410) common single nucleotide polymorphisms (SNPs) and T1DM risk but the findings have been conflicting. In 2006, Guo et al To confirm the association between 2 common polymorphisms (FokI and BsmI) in the VDR gene and T1DM susceptibility in Asian population, and to investigate regional geography-specific effects with T1DM, we performed an updated meta-analysis.To identify studies that investigated the association between T1DM susceptibility and VDR polymorphisms, the databases PubMed, Web of Science, CBM, Embase, Chinese Biomedical Literature Database, Chinese National Knowledge Infrastructure (CNKI) and Chinese Wanfang Data were searched independently by 2 reviewers. The last updated search was performed on March 29, 2013. The following search terms were used: (vitamin D receptor or VDR) AND (polymorphism or variation or mutation) AND (type 1 diabetes mellitus or IDDM or autoimmune diabetes). Studies published in English and Chinese were considered in our meta-analysis.The studies were included only if they met all the following inclusion criteria: (1) evaluation of 2 polymorphisms in the VDR gene and T1DM risk; (2) a case-control study design and (3) genotype distributions in both cases and controls available for estimating an odds ratio (OR) with 95% confidence interval (CI). Studies were excluded if they were case-only reports or review papers or the study was based on pedigree data. When the data were duplicated and had been published more than once, only the most recent and complete study was used.The following information was extracted from each study: (1) name of first author; (2) year of publication; (3) country of origin; (4) ethnicity of the study population; (5) gender distribution and mean age of subjects in cases and controls; (6) mean age of onset in cases; (7) genotype distributions in cases and controls; (8) P values for the test of Hardy–Weinberg equilibrium (HWE) in controls; (9) diagnostic criteria and (10) manner in which the controls were selected. Two authors independently assessed the articles for compliance with the inclusion criteria, and disagreement was followed by discussion or a third reviewer was asked to assess those articles until consensus was reached. When further information was required from a potentially relevant manuscript, the corresponding authors were contacted by the reviewers.The quality of the included studies was also independently assessed by 2 authors using the procedure known as ‘extended quality score’, which was used in the study by Xu et al 2 statistic test. P values <0.05 or I2>50% indicated that heterogeneity existed among studies, and the pooled OR of each study was calculated by the random effects model (REM), because it is more appropriate when there is significant heterogeneity. Otherwise, the fixed effects model FEM was used. If heterogeneity existed among studies, we used meta-regression to explore the source. The potential publication bias was estimated using Begg’s funnel plot and Egger’s test . If publication bias existed, the Duval and Tweedie nonparametric ‘trim and fill’ method was used to adjust the findings. Sensitivity analysis was performed to evaluate quality and consistency of the results. Data analysis was performed using STATA version 11.0 software.The strength of association between VDR polymorphisms and T1DM risk was assessed by ORs with a 95% CI. The HWE of the genotype distribution of controls was assessed via the χ2 goodness-of-fit test. The genetic models evaluated for pooled ORs of these polymorphisms were the additive model (A vs. G), the codominant model (AA vs. AG and AA vs. GG), the dominant model (GG vs. AA+AG) and the recessive model (AA vs. AG+GG). Statistical analysis was conducted by subgroup divisions on the basis of regional geography. The significance of the pooled ORs was determined using Z tests . The heterogeneity among studies was evaluated by the Q statistic test and IThe detailed steps of our literature search are shown in The characteristics of the studies are listed in A summary of the meta-analysis of the association between VDR gene polymorphisms and T1DM risk is provided in A total of 1,973 T1DM cases and 1,986 controls in 13 case-control studies were included in the meta-analysis for the relationship between the BsmI polymorphism and T1DM risk. Of these, 8 case-control studies were from the East Asian population, 1 was from the South Asian population and 4 were from the West Asian population. Our meta-analysis showed a significant overall association between the BsmI polymorphism and T1DM risk in all models , indicating a statistically robust result. The funnel plots were inspected for geometry and were found to be symmetrical, and no publication bias was detected by either Begg’s funnel plot  or the ESignificant heterogeneity was observed in most genetic model analyses (Table S4). We observed the pattern of heterogeneity: for BsmI, 9 out of 13 studies showed a positive result, and for FokI, 8 out of 13 studies showed a positive result. Thus, the heterogeneity in this meta-analysis may have resulted from the inclusion of a mixture of studies showing positive, null and inverse associations. To investigate this further, we used meta-regression analysis to determine the source of heterogeneity in publication year, ratio of males in cases and controls, mean age or onset age in cases, sample size in cases and controls, diagnostic criterion and quality scoring. Univariate meta-regression analysis showed that none of the tested covariates could explain the observed heterogeneity. Moreover, when the data were stratified by regional geography, the heterogeneity was not significantly decreased or eliminated.The two polymorphisms  in the VDR gene have been suggested as potential genetic factors for T1DM. However, the results from published studies are still inconsistent. The discrepancies may be partly attributed to differing genetic backgrounds and environment among various populations. To adjust for potential confounding factors in this meta-analysis, we examined the data by regional stratification across Asian populations. Our meta-analysis found that allele B was significantly associated with T1DM in the East Asian population, whereas FokI polymorphisms were associated with an increased T1DM risk in the West Asian population. Therefore, the BsmI polymorphism may increase the risk of T1DM in the East Asian population and the FokI polymorphism may increase the risk of T1DM in the West Asian population. However, considering the heterogeneity and the limited size of included studies, these results should be interpreted cautiously. Undoubtedly, further large scale case-control studies should be performed.In the present study, the heterogeneity was significant under some genetic models. Moreover, the heterogeneity was not remarkably decreased after stratified analysis or upon exclusion of the studies that deviated from the HWE. These findings were different from those of Zhang et al. Present study has some limitations that require consideration. First, studies have shown that the association between VDR polymorphisms and disease can vary by either past sun exposure or vitamin D level. Our meta-analysis was based on estimates without adjusting for sun exposure or dietary vitamin D intake, which may be one of the potential limitations. Second, lack of further adjustments of environmental risk factors, other covariables, the potential gene environment interactions might bias the present results. Third, because we only searched papers in English or Chinese, the completeness of evidence is impeded by language bias. Fourth, in the stratified analysis by regional geography, only 2 studies concerning the relationship between the BsmI polymorphism and the West Asian population were included; with such a small size, the possibility of finding a reliable association is limited. Thus, the conclusion on the relationship between the BsmI polymorphism and the West Asian population requires further confirmation. Moreover, only 1 study on the South Asia population was currently available for our meta-analysis, and stratified analysis for the South Asian population was not available. Thus, additional studies are needed to evaluate the effect of these functional polymorphisms on T1DM risk in West and South Asian population.In conclusion, the current meta-analysis indicates that the BsmI polymorphism may contribute to T1DM pathogenesis and may help to explain individual differences in the susceptibility to T1DM in the East Asian population. Furthermore, it shows that the FokI polymorphism may confers susceptibility to T1DM in the West Asian population. However, the power is not enough, and large, well-designed epidemiological studies are necessary to carefully explore the roles of VDR gene polymorphisms in the pathogenesis of T1DM in the Asian population.Figure S1Begg’s funnel plot analysis for the comparison of the FokI (A), BsmI (B) alleles. Each point represents an independent study for the indicated association. p value of Begg’s test was 0.695 and 0.225, respectively (continuity corrected).(TIF)Click here for additional data file.Table S1Characteristics of the studies included in the meta-analysis. “NA” means that the data were not available.(DOC)Click here for additional data file.Table S2Extended quality assessment criteria. Note: the full score is 14 points, if an original study has a quality score greater than or equal to 11 points, it is high-quality designed; and if a quality score less than 7 points, poor-quality designed; and if a quality score greater than or equal to 7 points and less than 11 points, medium-quality designed.(DOC)Click here for additional data file.Table S3Quality score of included study. HWE: Hardy-Weinberg equilibrium.(DOC)Click here for additional data file.


Studies focused on the correlation of mutations in the genome of Hepatitis B Virus (HBV) like Pre-S mutation, Basal Core promoter (BCP), Enhancer II (EnhII), especially Precore mutation, with the risk of hepatocellular carcinoma (HCC) have triggered stiff controversies. With an increasing number of studies in this field recently, we conducted this meta-analysis to appraise the correlations.st, 2012. Meta-analysis was performed in fixed/random-effects models using STATA 10.0. Publication bias was examined through Egger's test and Begg's funnel plot.We searched the commonly used databases both in English and Chinese till February 1OR = 0.002), G1899A  and Pre-S mutation especially Pre-S1 deletion  and Pre-S2 deletion . Similar correlation existed between BCP double mutation A1762T/G1764A, T1753V, C1653T and HCC. In subgroup analysis, the Asians, genotype C or HBeAg positive patients with certain above mutations may be more susceptible to HCC. Besides, the mutations like G1896A and BCP double mutation may be associated with the progression of the liver diseases.In total, 85 case-control studies were included involving 16745 HBV-infected patients, of whom 5781 had HCC. Statistically significant correlations were observed in Precore mutation G1896A (OR = 1.46, 95% confidence interval [CI] = 1.15–1.85, PPrecore mutation G1896A, G1899A, deletions in Pre-S region as well as the other commonly seen mutations correlated with the increased risk of HCC, especially in Asians and may predict the progression of the liver disease. Hepatocellular carcinoma (HCC) is the primary histological subtype of the liver cancer which ranks the fifth most prevalent cancer worldwide and the second leading cause of the cancer mortality HBV contains an incomplete double-stranded DNA genome consisting of four main regions: the PreS/S region (nucleotides or nt 2854–155), the enhancer II region, basal core promoter  region and the precore region. It has been demonstrated that mutations in the HBV genome which is pertinent to HCC invariably occur at the PreS region, EnhII, BCP and precore region. Those mutations include G1613A, C1653T in the EnhII region; T1753V, the double mutation A1762T/G1764A at the BCP region, G1896A and G1899A in the precore region However, several published studies showed a negative association between these mutations and the onset of HCC st 2012 using the following databases: PUBMED, Embase, Chinese Biomedical Literature Database (CBM) and China National Knowledge Infrastructure (CNKI). Medical Subject Heading (MeSH) terms were of the priority in setting the strategy. The key words were “hepatitis b virus” “mutation” and “hepatocellular carcinoma”. In addition, we scrutinized the reference citations in the retrieved articles so as not to miss any additional eligible studies.A comprehensive search was conducted till February 1Studies were included if they met the following criteria: 1) the article assessed the association between HBV mutations and HCC; 2) study design was a case-control study; 3) the diagnosis of each stage of liver disease conformed to the American Association for the Study of Liver Disease The data was collected by two members (Yun Liao and Xin Hu) independently, using the standardized form. When any discrepancy occurred, we consulted with the other investigators until the consensus was reached. The following information was extracted: first author's name, publication time, country, ethnicity, study design, sequencing method, number of cases (patients who have developed HCC) and controls (patients without HCC), mean age, male proportion, genotype distribution and mutation sites. Still, we extracted data based on subgroups like ethnicity, genotypes and HBeAg statuses etc.2 statistics (the heterogeneity could be accepted if P>0.1 and I2≤50%) and Galbraith plot for heterogeneity. If the value of I2 statistics was less than 50% or the P value is more than 0.1, the fixed-effects model can be tapped, otherwise, random-effects model be used. Galbraith plot was used to determine the main sources of the heterogeneity. Begg's funnel plot and Egger's test were performed to examine the publication bias. All the statistical analyses were performed using STATA (version 10.0). All tests were two sided.The impact the mutations have on HCC were estimated by summary odds ratios (OR) and their corresponding 95%CI. The overall effect was appraised through the Z test which could be deemed significant if the P value was less than 0.05. The heterogeneity for the included articles was evaluated using Cochran's Q test, IThe flow diagram See  describi2 = 77.6%, P<0.001), thus the random-effects model was used. Significant correlation was found between G1896A and the occurrence of HCC   . According to Galbraith plot, studies conducted by Lyu H OR = 0.041, I2 = 39.2%). While for HBeAg status subgroup, we didn't observe any significant association, but the trend toward significant association became increasingly obvious  See . When pe.84) See  as the m237) See . In the 237) See . For subious See .2 = 33.0%, Pheterogeneity = 0.135) and the fixed-effects model was used. Results showed that G1899A correlated with an increased risk of HCC   See . In subg2 = 3.9%, P = 0.411). Thus fixed-effects model was used to appraise the association between Pre-S1 deletion and HCC. Significant correlation was obtained  (See 2 = 43.3%) and random-effects model was used. The results indicated a significant correlation existed  (See 2 = 16.8%).For Pre-S mutation, we primarily focused on Pre-S1 deletion and Pre-S2 deletion. 11 articles including 807 HCC cases and 1820 controls were included for Pre-S1 deletion and no significant heterogeneity was observed (I.89) See . For Pre.50) See . Galbrai.50) See . After o2 = 76.1%, p<0.001), T1753V  and C1653T . Thus, for these mutations, random-effects model was used. Results showed that BCP double mutation A1762T/G1764A strongly correlated with the occurrence of HCC   See ; T1753V .95) See , and C16.95) See .In subgroup analysis by ethnicity, all the mutations correlated with the risk of HCC in Asians . In subgroup analysis by genotype, A1762T/G1764A in HBV genotype B and C, T1753V in HBV genotype C and D, C1653T in genotype C patients significantly correlated with the increased risk of HCC. While in HBeAg subgroup, BCP A1762T/G1764A was associated with the increased risk of HCC irrespective of the HBeAg status. But in HBeAg positive group, BCP double mutation correlated with a higher risk than in negative group. While for C1653T, a higher risk susceptible to HCC could be seen in the negative group See .Besides, during the process of extracting data, we found an escalating trend of the mutant rate accompanying the progression of the disease and almost no difference could be observed between liver cirrhosis group and HCC group Publication bias was only found in Pre-S2 deletion through egger's test (P = 0.033). From Galbraith plot, we saw Chen CH For all the mutations, sensitivity analysis was performed by sequential omission of every study respectively. For every mutation, the odds ratio was not significantly influenced by omitting any single study See .Our study showed that Precore mutation G1896A and G1899A, Pre-S1 deletion, Pre-S2 deletion and other common mutations mentioned above were all independently associated with an increased risk of HCC as well as the progression of liver diseases.Mutation G1896A locates at nt.1896 in the precore region leading to a G-to-A shift, which could induce a stop codon and subsequently suppress the expression of HBeAg Besides, G1899A also locates at Precore region of HBV genome and associated with a 3.14-fold increased risk of HCC compared with HBV patients without G1899A. For the mechanisms that underlie the interaction between G1899A and the onset of HCC still remain elusive. They may act as G1896A does but still merit further exploration. So far, this study is the first to report that significant correlation exists between G1899A and the increased risk of HCC based on a powerful meta-analysis, which might be a potential biomarker for foreseeing the occurrence of HCC.Pre-S1 deletion and Pre-S2 deletion are the two most commonly seen mutations in Pre-S region. From our study, both types of mutations significantly correlated with the increased risk of HCC . The deletion in Pre-S region would cause inefficient immune response and the pathogenesis of hepatocytes For the other common mutations, BCP double mutation A1762T/G1764A is generally accepted that it independently correlates with the risk of HCC and the progression of liver diseases From subgroup analysis by ethnicity, we could see that all the mutations mentioned in our study correlated with HCC among Asians, which might indicate that Asians would be more vulnerable to HCC. While for the relationship between genotypes and HCC, though the role of genotype in hepatocarcinogenesis remains elusive, several studies conducted in East Asia have proved that genotype C was more likely to cause severe liver disease like HCC than genotype B For the four stages of liver diseases, when we divided them into two groups: HCC and LC; chronic hepatitis and asymptomatic carrier, we found that the higher the incidence of HBV mutations, the more severe the liver disease. We found a 5.46-fold increased risk of HCC and LC in BCP double mutation, 2.77-fold in T1753V and 2.59-fold in C1653T. Precore G1896A was still associated with the progressive diseases contributing to a 1.85-fold increased risk suffering from a more severe disease status. Besides, Yin and his colleagues However, our study has several limitations. Firstly, a large number of studies were included in this study, and inevitably there existed heterogeneity which could not be easily eliminated. Thus we adopted random-effects model. When doing the sensitivity analysis, the odds ratios were not significantly affected. Therefore it should not influence the accuracy of our results. Secondly, when adjusting for heterogeneity, we excluded those outliers seen from Galbraith plot and during the excluding process, extra bias might be introduced. Thirdly, when taking subgroup analysis, only a few studies were available and the evidence seemed insufficient as well as unconvincing. Fourthly, since few studies involved the evaluation of the combination effects of these mutations on HCC, we did not summarize the total effects for the combination of these mutations. Lastly, only the data of those published articles in English or Chinese can be extracted and a potential bias would thus be introduced. Given these limitations, what we have found in this study should be interpreted prudently.Despite these limitations, our study indicates that Precore mutation G1896A is significantly associated with the increased risk of HCC and the progression of liver disease, especially among Asians. Besides, G1899A, Pre-S1 deletion, Pre-S2 deletion as well as other common mutations like BCP double mutation A1762T/G1764A, T1753V and C1653T, all of them correlate with HCC risk. For those results in subgroup analysis, they still need large-scale, well-designed case-control studies to prove. Since the development of the hepatocellular carcinoma can be attributed to multiple factors, what we have observed is only the tip of the iceberg. The future study could concentrate on the interaction of epigenetic influence as well as the genetic variations. Certainly, the environment and the host factors should be taken into consideration.Figure S1Forest plot for correlation of BCP double mutation A1762T/G1764A and HCC risk.(TIF)Click here for additional data file.Figure S2Forest plot for correlation of T1753V and HCC risk.(TIF)Click here for additional data file.Figure S3Forest plot for correlation of C1653T and HCC risk.(TIF)Click here for additional data file.Figure S4Galbraith plot for heterogeneity of BCP double mutation, T1753V and C1653T .(TIF)Click here for additional data file.Table S1Characteristics of eligible studies included in the meta-analysis.(DOC)Click here for additional data file.Table S2Odds ratio for correlation of the other common mutations with HCC risk in the meta-analysis.(DOC)Click here for additional data file.Table S3Sensitivity analysis of each mutation.(XLS)Click here for additional data file.


IL2 −330T>G, rs2069756), interleukin-6 , interferon-γ  as well as for the first time transforming growth factor-β1 . We recruited 151 subjects with schizophrenia and 279 controls. There was a significant difference in the genotype distribution and allelic frequency of the TGFB1 +869T>C between patients with schizophrenia and healthy controls (p < 0.05). The risk of schizophrenia was more than two-fold higher in carriers of T allele (CT+TT genotypes) than individuals with CC genotype. Given documented gender differences in incidence of schizophrenia, we conducted separate analyses of male and female participants. We have shown that the association was significant in females, while in males it reached a trend toward statistical significance. To the best of our knowledge, it is the first report showing the association between TGFB1 +869T>C polymorphism and schizophrenia.Immense body of evidence indicates that dysfunction of immune system is implicated in the etiology of schizophrenia. The immune theory of schizophrenia is supported by alterations in cytokine profile in the brain and peripheral blood. Given the strong genetic background of schizophrenia, it might be assumed that aberrant production of cytokines might be the consequence of genetic factors. This study aimed at investigating the association between schizophrenia susceptibility and selected functional polymorphisms in genes encoding cytokines including: interleukin-2 ( Schizophrenia is a severe mental illness that affects around 0.5 % of the general population . Most reIL2, INFG and IL6 are limited and inconsistent, therefore do not allow to draw unequivocal conclusions. In this study, we aimed to investigate the association between following polymorphisms: IL2 −330T>G (rs2069756), IL6 −174G>C (rs1800795), INFG +874T>A (rs2430561) in the Polish population and for the first time to investigate the role of selected TGFB1 polymorphisms—TGF-β1 +869T>C (rs1800470) and TGF-β1 +913G>C (rs1800471) in susceptibility to schizophrenia.Although dysfunction of immune response in schizophrenia has been repeatedly reported and meta-analyzed , 15, theWe recruited 151 patients with schizophrenia  and 279 controls . All subjects were of Caucasian origin and they were entirely native, unrelated Polish population recruited from the same geographic area—Lower Silesia region. The study was approved by Institutional Ethics Committee and all participants provided written informed consent prior to participation.All the patients were recruited from Wroclaw Medical University Hospital. They had a confirmed diagnosis of schizophrenia by the same two senior board-certified investigators according to DSM-IV criteria  based on individual interviews, clinical observation, medical records  and family information. Additionally, all patients were evaluated for lifetime psychotic symptomatology using the Operational Criteria for Psychotic Illness (OPCRIT) checklist, which provides a polydiagnostic categorical and dimensional approach to a diagnosis of schizophrenia . The OPCIL6 −174G>C (rs1800795), IFNG +874T>A (rs2430561), TGFB1 +869T>C (rs1800470) and TGFB1 +913G>C (rs1800471) were examined by the PCR with sequence specific primers technique (PCR-SSP) using the PCYTGEN kit . PCR products have been visualized on 2 % agarose gel.Genomic DNA was obtained from peripheral white blood cells from whole frozen blood using the QIAamp DNA Blood Mini Kit . IL2 −330T>G (rs2069756) polymorphism was examined using allelic Real Time PCR discrimination method with TaqMan SNP Genotyping Assay—C__15859930_10. The following polymorphisms 2 test. The χ2 analysis was also used to compare categorical data between patients with a diagnosis of schizophrenia and healthy controls subjects. In case when observed or expected values included a cell with a value <5, Fisher’s exact test was used. Odds ratios (OR) and 95 % confidence intervals (95 % CI) were calculated using the binary logistic regression model. Differences were considered as statistically significant if the p value was <0.05. Bonferroni adjustments were applied to the level of significance due to the multiple comparisons in TGFB1 gene. Analyses were performed using SHEsis software platform  allele correlates with increased production of TGF-β  allele was significantly more frequent in schizophrenia females than in healthy women, whereas this association did not reach statistical significance in males. In this regard, we provided additional evidence supporting the role of gender differences in the etiology of schizophrenia. Gender differences occur in several aspects of schizophrenia including epidemiological indices, age of onset, premorbid functioning, course and outcome of the disorder, subtle neurodevelopmental brain malformations and treatment response  allele along with higher IL-6 plasma level were associated with schizophrenia  allele was 48.88 %, while frequency of the A allele was 51.12 % in schizophrenia subjects. These results are similar to those obtained by our group  is highly discordant with our results . However, the genotype distribution in healthy controls significantly deviated from HWE . Lack of concordance with HWE may be due to the selection bias originating from population stratification, which increases the possibility of obtaining significant differences.The n factor . There iophrenia . The autDiscordant results of these studies might be attributed to several confounders including i.e. insufficient sample size, diversity of population characteristics, ethnic admixture and complexity of the phenotype . HoweverTGFB1 +869T>C gene polymorphism is associated with schizophrenia, especially in females. This finding suggests that previously reported alterations in the plasma level of TGF-β1 may occur due to genetic variation in its gene. Furthermore, gender differences in schizophrenia might be the consequence of the interaction between female hormones and TGF-β signaling. Thus, future studies should determine the link between TGF-β and the production of estrogens in schizophrenia. Our results do not support the association of polymorphisms in IL2, IL6 and IFNG genes with schizophrenia. Given that studies measuring the plasma level of these cytokines in schizophrenia subjects have provided relatively consistent findings that immune deregulation is implicated in schizophrenia, it might be concluded that altered production of IL-2, IL-6 and IFN-γ is not the consequence of genetic factors.Our results indicate that the


Suicidal behavior is a leading cause of injury and death worldwide. Several studies have provided a possible relationship between genetic factors and suicidal behavior. Also, these studies have shown evidence for altered serotonergic neural transmission in the pathogenesis of suicidal behavior. In addition, genes pertaining to the serotonergic system have been proposed as candidates to establish biological correlates between suicidal behavior and the serotonergic system. The most studied genes are SCL6A4, HTR2A, HTR2C, HTR1A, HTR1B, TPH-1, and TPH-2. To get a comprehensive understanding of the association with suicidal behavior we will conduct genotype assays studies in a Mexican population.p = 0.05 and the confidence interval at 95%.We will conduct a case–control study. The population sample will comprise adolescent and adult patients admitted for attempted of suicide and diagnosed by a psychiatrist. A peripheral blood sample will be taken from all the subjects (cases and controls). Genomic DNA from the leukocytes blood sample will be extracted. The genotypes of interest are distributed in the following genes: SCL6A4, HTR2A, HTR1A, HTR1B, HTR2C, TPH-2 and TPH-1. All the samples will be analyzed using a polymerase chain reaction (PCR) end-point method. We will evaluate the Hardy-Weinberg Equilibrium. The chi-squared test or Fisher’s exact test will be used to compare genotype and allele frequencies between control and case groups. The Quanto 1.2 software will measure the sample size of the association. For all the association analyses the level of significance will be set at Suicidal behavior has been increase in Mexico, principally in young population. Our study will demonstrate the association between serotoninergic genes and suicide behavior in Mexican population. Suicide is defined as the act of killing oneself in a voluntary way. The World Health Organization (WHO) classifies this action as a deliberate self-harm against oneself. SuicidaSuicide is considered a multifactorial event that involves biological, social, individual and environmental factors. SuicidaThe genes highlighted in the association with suicidal behavior are those that encode proteins of the serotonergic system. Moreover, low 5-hydroxyindoleacetic acid concentration (5-HIIA) in cerebrospinal fluid of depressed suicide attempters and in brain stems of completed suicides has been reported-19.The main genes implicated in suicidal behavior are associated with serotonin production and its transporter. The serotonin transporter (SLC6A4) has been the most studied in relation to SB. This gene is located in region 17q11.1-17q12. One of Other genes studied are serotonin receptors, mainly HTR2A, HTR1B and HTR2C. Several reports have analyzed the possible association of C102T HTR2A polymorphism with SB and have observed an excess of the C/C genotype in patients with suicide attempts-31. SimiOther genes that may play a role in SB pathogenesis are tryptophan hydroxylase (TPH) and monoamine oxidase A (MAO-A). The TPHThis article focuses on the analysis of SB in the Mexican population, particularly in the Tabasco state. The aim of this study is to determine the association of several serotonergic genes  with suicidal behavior in Mexicans.The population sample chosen for the study will comprise adolescent and adult patients (14–60 years old) admitted to the Regional Hospital of Comalcalco, Tabasco and Hospital “Gustavo A. Rovirosa P” and diagnosed with SB by a psychiatrist. We expect to recruit 500 cases. The inclusion/exclusion criteria will be the following: participants must be Mexican subjects descending from Mexican parents and grandparents, current substance abuse, history of substance dependence, history of bipolar disorder, concomitant medical or neurological illness, and intellectual disability. Also, the authorized control group will consist of physically healthy subjects on medical evaluation, with no manifested psychiatric problems, as assessed in brief interviews by psychiatrists; subjects will be recruited from the blood donor center of the same hospital. We expect to recruit 500 controls. SB diagnosis will be based on the DSM-IV instrument; disorders pertaining to Axis I, II and III will be considered. For the control group, a systematic interview will serve to obtain a detailed medical and psychiatric history. The time frame the recruitment of cases-controls will be November 2012 to November 2015.Written informed consent will be obtained from all subjects after they are given a detailed and extensive description of the study; they will not receive any economical remuneration. The study was approved by two Ethics Committee  and Research Committee of the university the Tabasco, México (DAMC-UJAT). Also, the study will be carried out in accordance with the ethical standards convened in the 1964 Declaration of Helsinki.A peripheral blood sample will be taken from all the subjects (cases and controls). Genomic DNA from the leukocytes blood sample will be extracted using a modified version of the protocol by Lahiri-40. The p = 0.05 and the confidence interval at 95%.Demographic factors will be evaluated with the statistics program SPSS v.16. In addition, we will evaluate the Hardy-Weinberg Equilibrium (HWE) using Pearson’s goodness-of-fit chi-squared test. The p value will be corrected according to the number of comparisons made in each locus. Also, the chi-squared test or Fisher’s exact test will be used to compare genotype and allele frequencies between control and case groups. The Quanto 1.2 software will measure the sample size of the association. For all the association analyses the level of significance will be set at Suicide is a major public problem around the world. Reports from the World Health Organization (WHO) indicate that suicide accounts for the largest share of self-harm in developed countries. Suicide is foreseen as an even greater contributor to the global burden of disease over the coming decades-7. In MeSuicidal behavior has increased substantially in Mexico, and this rise can not be explained solely by environmental factors. Although there are several reports on this issue in Mexico, to date there are no studies evaluating the role for a serotonergic pathway in association with suicidal behavior. Genetic research conducted in Mexico will try to establish the regulation of genes in the pathology of SB.WHO: World Health Organization; SB: Suicidal behavior; 5-HIIA: 5-hydroxyindoleacetic acid concentration; HTR2A: Serotonin 2A receptor; HTR2C: Serotonin 2C receptor; HTR1A: serotonin 1A receptor; HTR1B: Serotonin 1B receptor; TPH-1: Tryptophan hydroxylase 1; TPH-2: Tryptophan hydroxylase 2; HWE: Hardy-Weinberg Equilibrium.The authors declare that they have no competing interests.TZC and JRI conceived the study, participated in the design and helped to draft the manuscript. PGS, VSMP and VSM helped to select the clinical criteria for patients. GA, NH, GCTB and MLLN helped to select the genes and polymorphisms in the study. TZCA, GCTB and JSMA wrote the draft of the manuscript. All authors read, critically revised, and approved the final version of the manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-244X/14/29/prepub


Potential xeroderma pigmentosum group D (XPD), also called excision repair cross-complimentary group two (ERCC2), Lys751Gln and Asp312Asn polymorphisms have been implicated in gastric cancer risk among different ethnicities.We aimed to explore the effect of XPD Lys751Gln and Asp312Asn polymorphisms on the susceptibility to gastric cancer among different ethnicities through a systematic review and meta-analysis. Each initially included article was scored for quality appraisal. Desirable data were extracted and registered into databases. 13 studies were ultimately eligible for the meta-analysis of Lys751Gln polymorphism and 9 studies for the meta-analysis of Asp312Asn polymorphism. We adopted the most probably appropriate genetic model (recessive model) for both Lys751Gln and Asp312Asn polymorphisms. Potential sources of heterogeneity were sought out via subgroup and sensitivity analyses, and publication biases were estimated.Statistically significant findings were apparently noted in Asians but not in Caucasians for both XPD Lys751Gln and XPD Asp312Asn polymorphisms. A statistically significant finding could be seen in noncardia-type gastric cancer for XPD Lys751Gln polymorphism. A statistically significant finding could also be seen in high quality subgroup, small-and-moderate sample size subgroup, articles published after 2007, or PCR-RFLP genotyping subgroup for XPD Asp312Asn polymorphism.Our meta-analysis indicates that XPD Gln751Gln (CC) genotype and Asn312Asn (AA) genotype may seem to be more susceptible to gastric cancer in Asian populations but not in Caucasian populations, suggesting that the two genotypes may be important biomarkers of gastric cancer susceptibility for Asian populations, the assumption that needs to be further confirmed in well-designed studies among different ethnicities. Gln751Gln (CC) genotype may also be associated with noncardia-type gastric cancer risk, which should also be confirmed among different ethnicities in the future. Although worldwide gastric cancer incidence has decreased, its mortality still ranks second It is widely acknowledged that DNA must remain stable to undertake its crucial physiological functions, but it is persistently vulnerable to various endogenous and/or exogenous damages and thus its probable mutations could accumulate and carcinogenesis may occur due to the damaged DNA. DNA repair system, however, plays a vital role in maintaining the functions of normal cells and genome integrity through the reversal of the damaged DNA Nucleotide excision repair (NER), one of the major DNA repair pathways in humans, is capable of removing helix-distorting base lesions produced by ultraviolet light (UV) and an array of chemical agents et al. published the first study involved in XPD Lys751Gln polymorphism in relation to gastric cancer risk In 2005, Huang WY Accordingly, the aim of our meta-analysis was to explore, using the most appropriate genetic model, the effect of XPD polymorphisms on gastric cancer risk among different ethnicities and to identify possible sources of heterogeneity among the eligible studies.A systematic literature search was performed for articles regarding XPD/ERCC2 SNPs associated with gastric cancer risk. The MEDLINE, EMBASE databases, Chinese National Knowledge Infrastructure (CNKI), Web of Science, and BIOSIS databases were used simultaneously with the combination of terms “XPD”, “ERCC2”, “DNA repair”, “NER”, “Lys751Gln”, “Asp312Asn”, or “Arg156Arg”; “gene”; “polymorphism”, “variant”, or “SNP”; and “gastric cancer”, “gastric carcinoma”, or “stomach cancer” up to December 2011. The search was performed without any restriction on language. The scope of computerized literature search was expanded according to the reference lists of retrieved articles. The relevant original articles were also sought manually.Studies concerning the association of XPD/ERCC2 SNPs  with gastric cancer risk were included if the following conditions were met: (i) any study described the association of at least one of XPD/ERCC2 SNPs with gastric cancer; (ii) any study reported the numbers of both controls and gastric cancer cases; (iii) results were expressed as odds ratio (OR) with 95% confidence intervals (CI); and (iv) studies were case-control or nested case-control ones.et al.et al.et al.To identify high-quality studies, we mainly adopted predefined criteria for Quality Appraisal initially proposed by Thakkinstian Helicobacter Pylori infection status.The following data from each article were extracted: authors, year of publication, country, ethnicity of participants , study design, source of controls, number of controls and of cases, genotyping method, distribution of age and gender, Lauren's classification , anatomical classification (cardia or non-cardia cancer), smoking habit, drinking habit and The data were extracted and registered into two databases independently by two investigators (Lin B and Lu Y) who were blind to journal names, institutions or fund grants. Any discrepancy between these two investigators was resolved by the investigator (Xue H), who participated in the discussion with them and made an ultimate decision.All statistical analyses were performed using STATA statistical software . Two-sided Ps<0.05 were considered statistically significant. Hardy-Weinberg equilibrium (HWE) in controls was calculated again in our meta-analysis. The chi-square goodness of fit was used to test deviation from HWE (significant at the 0.05 level).1, OR2, and OR3 were calculated for genotypes CC versus AA, CA versus AA, and CC versus CA for XPD Lys751Gln polymorphism; AA versus GG, GA versus GG, and AA versus GA for XPD Asp312Asn polymorphism; AA versus CC, CA versus CC, and AA versus CA for XPD Arg156Arg polymorphism, respectively. The pairwise differences were used to determine the most appropriate genetic model. If OR1 = OR3≠1 and OR2 = 1, a recessive model is suggested. If OR1 = OR2≠1 and OR3 = 1, a dominant model is implied. If OR2 = 1/OR3 ≠1 and OR1 = 1, a complete overdominant model is suggested. If OR1>OR2>1 and OR1>OR3>1, or OR1<OR2<1 and OR1<OR3<1, a codominant model is indicated Odds ratios (OR) and 95% confidence intervals (95% CI) were used to assess the strength of associations between XPD/ERCC2 SNPs and gastric cancer risk. ORI2) value, representing variation in OR attributable to heterogeneity was then used to quantify the degree of such between-study heterogeneity I2<25% represents no heterogeneity, I2 = 25–50% represents moderate heterogeneity, I2 = 50–75% represents large heterogeneity, and I2>75% represents extreme heterogeneity”. Between-study variance Tau-squared (τ2) value was also used to evaluate between-study variance. A fixed-effects model, using Mantel–Haenszel (M–H) method, was employed to calculate the pooled ORs when homogeneity existed on the basis of Q-test p value no less than 0.1.By contrast, a random-effects model, using DerSimonian and Laird method (D+L), was utilized if there was heterogeneity based on Q-test p value less than 0.1. Even for the homogeneity among-studies, D+L method was also used. Meta-regression analyses and subgroup analyses were utilized to explore and control potential sources of heterogeneity across studies. The significance of pooled ORs was tested by Z test (P<0.05 was considered significant).The Q statistic was used to assess heterogeneity across studies included in the meta-analysis. I-squared , OR2 , and OR3  were 1.22 (p = 0.266), 1.11 (p = 0.369), and 1.02 (p = 0.811), respectively, hardly insinuating a particular model effect of putative susceptible C allele. Heterogeneity chi-squared was 29.83 (d.f. = 12), p value was 0.003, and I2 was 59.8%. After meta-regression analysis using single covariate , p values of coefficient t value for Asians, Caucasians, or Turkish population were 0.001, 0.139, and 0.585, respectively; strongly indicating that Asians single covariate could mostly constitute the source of heterogeneity across studies. τ2 for Asians, Caucasians, or Turkish population single covariate were 0, 0.09178, and 0.1347, respectively. For Asians single covariate, τ2 decreased from 0.1233 to 0, indicating Asians single covariate could account for 100% of the source of heterogeneity across studies. When stratified by ethnicity subgroup analysis, OR1 , OR2 , and OR3  among Asian population were 2.63 (p = 0.002), 1.14 (p = 0.653), and 1.51 (p = 0.034), respectively, highly indicating a recessive model effect of putative susceptible C allele (OR1 = OR3≠1 and OR2  = 1).For XPD Lys751Gln polymorphism, OR1 , OR2 , and OR3  were 1.75 (p = 0.015), 1.15 (p = 0.549), and 1.47 (p = 0.003), respectively, highly indicating a recessive model effect of putative susceptible A allele (OR1 = OR3≠1 and OR2 = 1). Heterogeneity chi-squared was 9.91 (d.f. = 8), p value was 0.272, and I2 was 19.2%, indicating no heterogeneity across studies. After meta-regression analysis using single covariate (ethnicity composed of Caucasians or Asians), p value of coefficient t value for ethnicity single covariate was 0.277, indicating that ethnicity could constitute one of the sources of little heterogeneity across studies. τ2 decreased from 0.0354 to 0.02075, indicating ethnicity could account for 41.4% of the source of little heterogeneity across studies. Similarly, when stratified by ethnicity subgroup analysis, OR1 , OR2 , and OR3  among Asian population were 2.10 (p = 0.026), 1.22 (p = 0.574), and 1.80 (p = 0.008), respectively, further indicating a recessive model effect of putative susceptible A allele (OR1 = OR3≠1 and OR2 = 1).For XPD Asp312Asn polymorphism, ORTaken together, a recessive genetic model was ultimately chosen for both XPD Lys751Gln and XPD Asp312Asn polymorphisms in our meta-analysis.I2 were 0.0%, 0.0%, and 75.1%; and τ2 were 0.0000, 0.0000, and 0.4489, respectively, demonstrating no heterogeneity within Caucasians or Asians, but extreme heterogeneity within Turkish population  and low-and-moderate quality (scores less than 6.5) subgroups. As for XPD Lys751Gln polymorphism, no statistically significant finding was witnessed in either high quality subgroup or low-and-moderate quality counterpart, given that the pooled ORs  were 1.20  for the former and 0.61  for the latter. When ethnicity sub-stratification was performed for high quality subgroup, a statistically significant finding was much apparently witnessed among Asians but no statistically significant finding was noted among Caucasians because the pooled ORs  were 2.54  for the former and 0.98  for the latter, respectively. As for Asp312Asn polymorphism, a statistically significant finding was witnessed in high quality subgroup but not in low-and-moderate quality counterpart, given that the pooled ORs  were 1.56  for the former and 1.42  for the latter. Likewise, when ethnicity sub-stratification was performed for high quality subgroup, a statistically significant finding was much apparently witnessed among Asians but no statistically significant finding was noted among Caucasians because the pooled ORs  were 2.37  for the former and 1.31  for the latter, respectively.The data were additionally stratified, in line with publication time, into the earlier publication subgroup (articles published before or in 2007) and the later publication subgroup (articles published after 2007). As for XPD Lys751Gln polymorphism, no statistically significant findings were observed on the grounds that the pooled ORs  were 0.89  in the former and 1.23  in the latter, respectively. As for Asp312Asn polymorphism, a statistically significant finding was observed in the later publication subgroup but not in the earlier publication subgroup on the grounds that the pooled ORs  were 1.46  in the former and 1.61 in the latter, respectively.When gastric cancer was classified into non-cardia  and cardia subtypes, a statistically significant finding was found among non-cardia type but not among cardia type for XPD Lys751Gln polymorphism on the grounds that the pooled ORs  were 2.03  among non-cardia type and 0.88  among cardia type. As for Asp312Asn polymorphism, no statistically significant finding was observed among cardia type on the grounds that the pooled OR  was 0.89 , but OR  regarding non-cardia type could not be calculated because only one study In terms of pathology, gastric cancer could be classified into intestinal, diffuse, or mixed subtypes, but only 1 study Helicobacter pylori infection or smoking status could not be analyzed in our meta-analysis because necessary relevant data of at least two studies could not be accessible in our meta-analysis.Confounding factors such as And when genotyping techniques were considered, no statistically significant finding was noted in each genotyping technique subgroup for XPD Lys751Gln polymorphism because pooled ORs  were 0.94  and 1.67  in RFLP and TagMan subgroups, respectively; however a statistically significant finding was noted in RFLP genotyping subgroup but not in Direct sequencing subgroup for Asp312Asn polymorphism because pooled ORs  were 1.90  and 1.24 , respectively.Engin AB et al., also deviated from HWE, the OR  became 1.19  for the all ethnicity, indicating high stability of the results. If all the three deviated-HWE studies Meta-analyses were conducted repeatedly when each particular study had been removed. The results indicated that random-effects estimates before and after the deletion of each study were similar at large, suggesting moderately high stability of the meta-analysis results. For XPD Lys751Gln polymorphism, as shown in For Asp312Asn polymorphism, as shown in Cumulative meta-analyses of XPD Lys751Gln polymorphism association were also conducted among Asians and Caucasians via the assortment of publication time and total number of sample size. As shown in Publication bias was preliminarily examined by funnel plots qualitatively and estimated by Begg's and Egger's tests quantitatively. For XPD Lys751Gln polymorphism, its funnel plot  showed tIn our meta-analysis statistically significant findings were apparently noted in Asians but not in Caucasians for both XPD Lys751Gln and XPD Asp312Asn polymorphisms. Also based on the findings of cumulative meta-analyses, the inclinations toward significant associations in Asians for both XPD Lys751Gln and XPD Asp312Asn polymorphisms could be obviously seen when sorted by publication time and total sample size. XPD Gln751Gln (CC) and Asn312Asn (AA) genotypes may seem to be more susceptible to gastric cancer in Asians. Our meta-analyses suggest that Gln751Gln (CC) and Asn312Asn (AA) genotypes may be important biomarkers of gastric cancer susceptibility for Asians, the assumption that needs to be further confirmed in future well-designed studies in Asian populations. Also the different or even conflicting risk associations, if so, among different ethnicities should be further meticulously investigated and reconfirmed in the future.I2 (%) was 19.2 and τ2 was 0.0354, as shown in I2 (%) and τ2 became 0.0 and 0.0000 for Asians and 41.6 and 0.0587 for Caucasians, respectively, further indicating that, actually, no heterogeneity existed among Asians studies rather than among Caucasians counterparts. Given this, we think that stratification or subgroup analyses are still needed in our meta-analysis. For XPD Asp312Asn polymorphism, our subgroup analyses also indicate that significant associations could be found in the small-and-moderate sample subgroup but not in the large sample counterpart. In large sample subgroup the ORs in the studies conducted by Capellá G et al. For XPD Asp312Asn SNP, although For XPD Asp312Asn polymorphism, a statistically significant finding was witnessed in high quality subgroup but not in low-and-moderate quality counterpart. When ethnicity sub-stratification was performed for such a high quality subgroup, a statistically significant finding was even more apparently witnessed among Asians but still no statistically significant finding was noted among Caucasians. For XPD Lys751Gln polymorphism, no statistically significant finding originally noted in high quality subgroup interestingly changed into a statistically significant finding among Asians but still not among Caucasians when ethnicity sub-stratification was performed for such a high quality subgroup. Those findings observed in different ethnic high quality subgroups further indicate the point that XPD Gln751Gln (CC) and Asn312Asn (AA) genotypes may be more susceptible to gastric cancer in Asians rather than in Caucasians. Certainly, high-quality studies should be more advocated to be designed in the future so as to accurately explore the real associations between XPD polymorphisms and gastric cancer risk among different ethnicities. Besides Asians and Caucasians, other ethnic participants, if possible, should be more appraised in the future.Moreover, as for XPD Lys751Gln polymorphism, 4 Helicobacter pylori infection, alcoholic drinking, and smoking habits may be associated with increased damage to DNA repair Furthermore, a variety of confounding factors such as With the advent of novel genotyping technologies like seminested polymerase chain reaction, TaqMan allelic discrimination test, or real-time PCR, we may witness an upsurge of genetic association studies in the future. As for XPD Asp312Asn polymorphism in our meta-analysis, a statistically significant finding could be noted in PCR-RFLP subgroup but not in Direct sequencing subgroup. As for XPD Lys751Gln polymorphism, however, no statistically significant finding was witnessed in either PCR-RFLP subgroup or TagMan PCR genotyping subgroup. Certainly, the difference should be concerned with extreme caution. Unfortunately, no direct sequencing was used among XPD Lys751Gln polymorphism studies. For a novel genotyping technique to be employed for the study of a particular genetic polymorphism, this technology, to our knowledge, should better be confirmed using direct sequencing. In that case, this new technology can be seen as valid as direct sequencing Finally, the strength of our meta-analysis could be summarized as follows. We sought to find as many publications as we could by means of various searching approaches. The study that appeared to deviate from HWE was not excluded mechanically in our meta-analysis unless there are other convincing grounds for doubting the quality of the study To be sure, there are some unavoidable limitations in our meta-analysis. Firstly, the offered information from the included studies is inconsistent. Put it another way, the information about overall gastric cancer susceptibility is predominantly provided, while more important information about pathologic subtypes or anatomic subtypes of gastric cancer is less provided. Thus, the specific subtype results should be considered with caution. Secondly, with the merely published studies included in our meta-analysis, publication bias is very likely to occur, though no or a little statistically significant publication bias is indicated in our meta-analysis. Thirdly, moderate to severe heterogeneity could be witnessed among the included studies. So as to minimize the potential bias, we designed a rigorous protocol before conducting meta-analysis, and performed a scrupulous search for published studies using explicit methods for study selection, data extraction, statistical analysis, adoption of the most appropriate genetic model and sensitivity analysis.In conclusion, XPD Gln751Gln (CC) and Asn312Asn (AA) genotypes may seem to be more susceptible to gastric cancer in Asian population but not in Caucasian population, suggesting that Gln751Gln (CC) and Asn312Asn (AA) genotypes may be important biomarkers of gastric cancer susceptibility for Asian population, the assumption that needs to be further confirmed in future well-designed studies among different ethnicities. Gln751Gln (CC) genotype may also be associated with the noncardia-type gastric cancer risk, the finding that also needs to be further confirmed.Table S1Scales for Quality Assessment.(DOC)Click here for additional data file.


TPH2), a genotype. Previous studies found that mutations on the TPH2 locus in humans were associated with depression and studies of mice and studies of rhesus macaques have shown that the TPH2 locus was involved with aggressive behavior. We previously reported a functional single nucleotide polymorphism (SNP) in the form of an amino acid substitution, Q468R, in the chimpanzee TPH2 gene coding region. In the present study we tested whether this SNP was associated with neuroticism in captive and wild-born chimpanzees living in Japan and Guinea, respectively. Even after correcting for multiple tests (Bonferroni p = 0.05/6 = 0.008), Q468R was significantly related to higher neuroticism . This study is the first to identify a genotype linked to a personality trait in chimpanzees. In light of the prior studies on humans, mice, and rhesus macaques, these findings suggest that the relationship between neuroticism and TPH2 has deep phylogenetic roots.In the brain, serotonin production is controlled by tryptophan hydroxylase 2 ( TPH) TPH2 is preferentially located in the dorsal raphe region of the brain TPH2 was identified in patients with major depression TPH2 gene polymorphisms. Chen et al. (2010) also reported a functional polymorphism in the 3′ untranslated region of the TPH2 gene in rhesus macaques, which was related to differential hypothalamus-pituitary-adrenal axis functioning, and, among peer-reared infants, was associated with the aggressive behavior Serotonin (5-HT) production is mediated by the rate-limiting enzyme tryptophan hydroxylase  5-HTTLPR) is present in the regulatory region of 5-HTT gene S) of this gene is transcribed less efficiently than the long allele (L), resulting in decreased 5-HTT expression 5-HTTLPR was significantly associated with anxiety-related traits: individuals with the SS or SL genotype presented higher neuroticism scores than those with the LL genotype. Several studies The role of the serotonergic system in neuroticism, depression, anxiety-related traits, and disorders has been extensively studied Previous studies indicated that chimpanzee personality can be defined by five personality domains analogous to those of humans  and a broad, chimpanzee-specific domain labeled dominance 5-HTTLPR gene in chimpanzees was monomorphic th position of the tryptophan hydroxylase 2 (TPH2) gene - the adenine (A) nucleotide was substituted with guanine (G) th glutamine  with arginine . An enzyme activity assay of these genotypes indicated that the capacity of L-5-hydroxytrytophan (serotonin) biosynthesis was significantly higher for ch468R than ch468Q In a prior study, we found that the 5-HTTLPR gene which is related to human neuroticism In the present study we examined the association between the Q468R polymorphism and neuroticism in chimpanzees. Like the short version of the human The sample consisted of 57 chimpanzees. Of these chimpanzees, 21 were cared for at the Chimpanzee Conservation Center, Guinea, West Africa. These individuals were wild-born orphans, rescued from the illegal pet trade, and in the process of being rehabilitated. Of the 36 remaining chimpanzees, 26 lived in Chimpanzee Sanctuary Uto This study was carried out within the ethical guidelines and framework of Kyoto University and was approved by the Primate Research Institute, Kyoto University and Chimpanzee Sanctuary Uto . All procedures were conducted according to the second edition of the Guide for the Care and Use of Laboratory Primates  and the Guideline for Care of Chimpanzees (Chimpanzee Sanctuary Uto). The details of animal welfare and steps taken to ameliorate suffering were in accordance with the recommendations of the Weatherall report, “The use of non-human primates in research”.5-TTCTGTTTATTCTGCA-GGGACT-3′ and TPH2R: 5′-TTAGCCAAGCCATGACACAG-3′) were used to amplify the 1404th SNP containing fragments of TPH2, which was then digested using a restriction enzyme, HpyCH4V . The digested fragments were subsequently separated by electrophoresis on a 2.0% agarose gel .Chimpanzees were scored by raters using a Japanese translation of the Hominoid Personality Questionnaire TPH2 genotype and personality in the chimpanzees living at the Chimpanzee Conservation Center in Guinea and those living in Chimpanzee Sanctuary Uto in Japan. We then tested for this association in all 57 subjects (the combined study sample), which included the 10 chimpanzees living in the Kyoto University Primate Research Institute and Japanese zoos. In our first model we examined the possibility of additive genetic effects. We therefore coded AA, AG, and GG as 0, 1, and 2, respectively. In our second model we examined the possibility of genetic dominance by coding We then tested the dominance genetic mode by comparing individuals with the AA genotype (coded 0) and individuals with either the AG or GG genotype (coded as 1). Chimpanzee personality traits and TPH2 genotypes were analyzed using linear regressions controlling for sex and age. SPSS (15.0) was used to conduct all analyses.To cross-validate results, we first separately tested for the association between the p = 0.05/6 = 0.008).The ch468R allele was associated with higher dominance in a sample of chimpanzees living in Chimpanzee Sanctuary Uto. The association between this allele and dominance was not present among the wild-born sanctuary chimpanzees in Guinea or in the total sample. There was also a statistically non-significant trend suggesting that neuroticism in chimpanzees was associated with the ch468R allele in Chimpanzee Sanctuary Uto. Moreover, while this relationship was not statistically significant, the effect size and direction of the effect were comparable in the chimpanzee sample from Guinea. Finally, in the total sample, there was a significant association between the presence of the ch468R allele and higher levels of neuroticism.One possible reason for the failure to cross-validate the dominance findings is that the wild-born sanctuary chimpanzees were younger than those at Chimpanzee Sanctuary Uto. As such, the dominance dimension may not yet have as clearly been expressed as in the more mature individuals. A second possible explanation for our failure to cross-validate the dominance findings in the wild sample is because they were separated from their mothers early in life and may have been subjected to other trauma.TPH2 in rhesus macaques was associated with aggressive behavior TPH2 polymorphism (Q468R) is a gain-of-function mutation, which increases serotonin biosynthesis S allele of 5-HTTLPR which has been related to human neuroticism, the ch468R allele of the TPH2 gene works to increase serotonin storage in the synapse by increasing production of and decreasing the re-absorption of serotonin.There does appear to be evidence of an association between neuroticism and ch468R. This is consistent with earlier studies of humans G allele was dominant, though this may reflect the small sample size of each group.One shortcoming of the present study was the small sample size and thus these results require replications in larger independent samples. A second shortcoming is our poor knowledge of the background of the chimpanzees which prevented us from testing for any gene by environment interaction effects. A third shortcoming is that, while we included a model for dominance effects, the mean neuroticism across genotypes were only suggestive with respect to whether the TPH2 gene and phenotypes related to neuroticism in humans, mice and rhesus macaques suggests that the relationship between neuroticism and TPH2 has deep phylogenetic origins.Chimpanzees have highly-developed brains and exhibit a variety of psychological and behavioral traits in their elaborate social interactions. The present study is the first to identify a genotype related to a personality trait in chimpanzees. Understanding differences in the genes responsible for behavioral variation could lead to a better understanding of the evolutionary history of humans and chimpanzee This is the first report of a relationship between a personality trait and genotype in great apes. Genetic markers for behavior may be useful for primate conservation, welfare and management in zoos. Therefore, the association between Q468R polymorphism and neuroticism identified in this study should be a focus of future studies which seek to understand individual differences in chimpanzee personality.


RAGE polymorphisms  and coronary heart disease (CHD) has been reported in various ethnic groups; however, these studies have yielded contradictory results.Recent data from human and animal studies have shown an upregulated expression of advanced glycosylation end product–specific receptor (RAGE) in human atherosclerotic plaques 1 and in retina, messangial, and aortic vessels, suggesting an important role of RAGE in the pathogenesis of atherothrombotic diseases. In the past few years, the relationship between RAGE polymorphisms and susceptibility to CHD. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated.PubMed, ISI web of science, EMBASE and the Chinese National Knowledge Infrastructure databases were systematically searched to identify relevant studies. Data were abstracted independently by two reviewers. A meta-analysis was performed to examine the association between A total of 17 studies including 4343 patients and 5402 controls were involved in this meta-analysis. Overall, no significant results were observed for −429T/C , −374T/A  and G82S  polymorphism. In the stratified analyses according to ethnicity, sample size, CHD endpoint and Hardy-Weinberg status, no evidence of any gene-disease association was obtained.This meta-analysis demonstrates that there is no association between the RAGE −429T/C, −374T/A and G82S polymorphisms and CHD. Coronary heart disease (CHD), including its most severe complication, myocardial infarction, is the leading cause of death in the industrialized world. Traditional risk such as hypertension, diabetes mellitus, dyslipidemia and smoking can only explain approximately two-thirds of the observed clinical events. This has maintained interest in other biochemical and genetic factors that might contribute to the underlying pathophysiology of vascular disease.RAGE gene, located on chromosome 6p21.3, contains 11 exons and a 1.7-kb 5′-flanking region RAGE gene, including functional polymorphisms −429T/C (rs1800625) in the promoter region, −374T/A (rs1800624) in intron 7 and G82S (rs2070600) in exon 3, have been implicated in the development of diabetic atherosclerosis Recently, an important role of receptor for advanced glycation end product (RAGE) in the pathogenesis of vascular diseases has generated great interest. RAGE is a multiligand member of the immunoglobulin superfamily of cell surface molecules RAGE polymorphism as a modulator of CHD susceptibility, previously inconsistent results have appeared in the literature. Published studies have generally been restricted in terms of sample size and ethnic diversity, and individual studies may have insufficient power to achieve a comprehensive and reliable conclusion. We therefore performed a meta-analysis of the published studies to clarify this inconsistency and to establish a comprehensive picture of the relationship between RAGE and CHD.Despite the biological plausibility of RAGE gene described above were retrieved, and their references were checked to identify other relevant publications. All relevant reports identified were included without language restriction.The literature included in our analysis was selected from PubMed, ISI web of science, EMBASE and Chinese National Knowledge Infrastructure (CNKI) with keywords relating to the relevant gene  in combination with words related to CHD . Genetic association studies published before May 2012 on CHD and polymorphisms in the Eligible studies had to meet all of the following criteria: (1) original papers containing independent data published in a peer-reviewed journal; (2) genotype distribution information in cases and controls or odds ratio with its 95% confidence interval and P-value.; (3) case–control or cohort studies; and (4) the diagnosis of CHD patients was confirmed pathologically or angiographically. The major reasons for exclusion of studies were (1) overlapping data and (2) case-only studies, family-based studies and review articles.Information was carefully extracted from all eligible publications independently by two authors according to the inclusion criteria listed above. The following data were collected from each study: first author, year of publication, diagnosis criterion, ethnicity, Hardy–Weinberg equilibrium (HWE) status, genotyping method, source of control, age, sex, body mass index (BMI), total number of cases and controls and genotype frequency in cases and controls. Relevant clinical outcomes included confirmed MI  and coronary stenosis (defined as at least 50% stenosis of one or more major coronary arteries on the basis of computer assisted assessments). For studies in which data could not be separated according to type of CHD from published data, cases were classified in the more inclusive category of coronary stenosis for the purpose of subsidiary analyses. Discrepancies in data extraction were resolved by discussion between all authors through consensus. Studies with different ethnic groups were considered as individual studies for our analyses.RAGE gene polymorphisms and CHD risk. For −429T/C, −374T/A, and G82S polymorphism, we pooled the OR by comparing risk allele carrier genotypes versus wild-type genotype for low frequency of homozygous variant. Heterogeneity was assessed with standard Q-statistic test. If heterogeneity existed, the random effects model (the DerSimonian and Laird method) Deviation from Hardy–Weinberg equilibrium was examined by Chi-square test. Odds ratio (OR) with 95% confidence intervals (CIs) was used to assess the strength of association between the In order to assess the stability of the results, one-way sensitivity analyses were performed by removing each individual study in turn from the total and re-analyzing the remainder. Publication bias was assessed using Egger’s test and Begg’s funnel plots The combined search yielded 101 references. Study selection process was shown in The crude ORs were performed for A allele carriers versus non-carriers. Individuals carrying the risk A allele were not statistically significant associated with an increased risk to coronary heart disease compared with those non-carriers. The summary OR was 1.01 [95% CI: 0.92–1.12, P(Z)  = 0.78, P(Q) = 0.12; Overall, the OR of the −429T/C polymorphism for CHD was 1.11 [95% CI: 0.98–1.26; P(Z)  = 0.09, P(Q) = 0.30; −5; In the overall analysis, the S allele was not significantly associated with elevated CHD   = 0.41, P(Q) <10Haplotype analyses between −429T/C, −374T/A, and G82S polymorphisms were performed in the 3 studies, involving 1461 cases and 1516 controls. No association between CHD and −429T/C, −374T/A, and G82S polymorphism is supported by the linkage disequilibrium (LD) analyses . The pooA single study involved in the meta-analysis was deleted each time to reflect the influence of the individual dataset to the pooled ORs, and the corresponding pooled ORs were not qualitatively altered, suggesting stability of the meta-analyses. Begg’s funnel plot and Egger’s test were performed to access the publication bias of the literatures. The shape of the funnel plots was symmetrical for these polymorphisms  and S4. RAGE gene. Its strength was based on the accumulation of published data giving greater information to detect significant differences. In total, the meta-analysis involved 17 studies for CHD which provided 4343 cases and 5402 controls.Large sample and unbiased epidemiological studies of predisposition gene polymorphisms could provide insight into the in vivo relationship between candidate genes and complex diseases. The present meta-analysis provides the first comprehensive assessment of the risk of CHD and three variants on RAGE gene and CHD susceptibility. Meanwhile, haplotypes analyses of the −429T/C, −374T/A, and G82S polymorphisms reveal the no association between the combination of these alleles and risk of CHD. For the subgroup analysis based on ethnicity, sample size, CHD endpoint and HWE status, we were unable to observe any effect modification, which is in line with the pooled analysis. In addition, data from the studies did not exhibit statistically significant heterogeneity in the majority of contrasts. There are some points should be concerned for the inconsistent results in early reports. Firstly, ethnic differences may attribute to these different results, since the distributions of the RAGE polymorphism were different between various ethnic populations. For instance, the frequencies of RAGE −374T/A polymorphism allele differs from 14% in Chinese population RAGE polymorphism. Thus, even if the variation has a causal effect on CHD, it may take a long time to be observed.Through the combined examination of independent studies, we did not find evidence supporting a positive relation between −429T/C, −374T/A, and G82S polymorphism of the RAGE promoter gene polymorphisms in atherothrombosis If genetic susceptibility to CHD is, in part, mediated through metabolic gene polymorphisms, it is possible that the combinations of certain genotypes may be more discriminating as risk factors for CHD than a single locus genotype. Previously study have found that haplotypes carrying either the −429T/C or the −374T/A variant are associated with reduced risk of MI and ischemic stroke, respectively, suggesting a protective role for RAGE gene is getting important for being the candidate gene for atherosclerosis and the other associated diseases. In addition, −429T/C and −374T/A gene variants have been shown to have a 2-fold and 3-fold increase in transcriptional activity, respectively Advanced glycation end products (AGEs) show their effects in extracellular matrix, in vascularate and by binding to their receptors (RAGE). Because of their prothrombotic and proinflammatory effects of RAGEs, the single nucleotide polymorphisms of Endogenous secretory RAGE (esRAGE) is an endogenous splicing RAGE variant. Administration of soluble RAGE isoforms inhibited atherogenesis and mitigated further progression of atherosclerotic lesions in diabetic mice In interpreting the result s, some limitations of this meta-analysis should be addressed. Firstly, lacking of individual-level data prevent us from making further analysis to identify any interactions between genetic variation and metabolic traits. Secondly, in the subgroup analyses, different ethnicities were pooled in the Asian ethnic group which may bring in some heterogeneity. As studies among specific ethnic group are currently limited, further studies including a wider spectrum of subjects should be carried to investigate the role of these variants in different populations. Thirdly, the overall outcomes were based on individual unadjusted ORs, while a more precise evaluation should be adjusted by other potentially suspected factors including age, sex, diabetes status, and environmental factors. Finally, because of the complex nature of CHD, it is unlikely that a SNP in one single gene would be obviously associated with an increase in asthma risk, without consideration of any other polymorphic susceptible genes.RAGE with CHD. The importance of these polymorphisms as a predictor of the risk of CHD is probably very small and the screening utility of this genetic variant in asymptomatic individuals may not be warranted. It is also known that the pathogenesis of CHD is complex and polygenetic in the vast majority of patients, with several genes, each with a small to moderate effect, acting individually, together or in association with important environmental determinants. Larger studies of different ethnic populations, especially with detailed individual information, are needed to confirm our findings.To conclude, our meta-analysis did not support an association of the −429T/C, −374T/A, and G82S polymorphism of Figure S1The flow chart of the included studies.(TIFF)Click here for additional data file.Figure S2Begg’s funnel plot of RAGE −374T/A polymorphism and coronary heart disease risk.(TIFF)Click here for additional data file.Figure S3Begg’s funnel plot of RAGE −429T/C polymorphism and coronary heart disease risk.(TIFF)Click here for additional data file.Figure S4Begg’s funnel plot of RAGE G82S polymorphism and coronary heart disease risk.(TIFF)Click here for additional data file.Table S1Minor allele distribution in cases and controls.(DOC)Click here for additional data file.Table S2Pairwise polymorphisms LD analysis.(DOC)Click here for additional data file.Table S3Meta analysis of haplotype combinations between −429T/C, −374T/A, and G82S polymorphisms of RAGE gene and CHD risk.(DOC)Click here for additional data file.Checklist S1PRISMA Checklist.(DOC)Click here for additional data file.


Several epidemiologic studies have evaluated the association between nonsteroidal anti-inflammatory drugs (NSAIDs) and bladder cancer risk and the results were varied. Thus, we conducted a comprehensive meta-analysis of studies exclusively dedicated to the relationship between the 3 most commonly used analgesics and bladder cancer risk.A systematic literature search up to November 2012 was performed in PubMed database for 3 categories of analgesics: acetaminophen, aspirin or non-aspirin NSAIDs. Study-specific risk estimates were pooled using a random-effects model.Seventeen studies (8 cohort and 9 case-control studies), involving a total of 10,618 bladder cancer cases, were contributed to the analysis. We found that acetaminophen  and aspirin  were not associated with bladder cancer risk. Although non-aspirin NSAIDs was statistically significantly associated with reduced risk of bladder cancer among case-control studies (but not cohort studies), the overall risk was not statistically significant . Furthermore, we also found that non-aspirin NSAIDs use was significantly associated with a 43% reduction in bladder cancer risk among nonsmokers , but not among current smokers.The results of our meta-analysis suggest that there is no association between use of acetaminophen, aspirin or non-aspirin NSAIDs and bladder cancer risk. However, non-aspirin NSAIDs use might be associated with a reduction in risk of bladder cancer for nonsmokers. Bladder cancer is the most common malignant tumor of the urinary system. According to the International Agency for Research on Cancer for 2008, about 386,300 individuals were diagnosed with bladder cancer and 150,200 died as a result. The majority of bladder cancer occurs in males and the highest incidence rates are found in the countries of Europe, North America, and Northern Africa Cigarette smoking and occupational exposures are the main risk factors for bladder cancer in Western countries, whereas chronic infection with Schistosoma hematobium in developing countries accounts for about 50% of the total burden Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most frequently used drugs worldwide. Experimental and epidemiologic evidence strongly suggests that aspirin and non-aspirin NSAIDs have shown promise as chemopreventive agents A systematic literature search up to November 1 of 2012 was performed in PubMed database to identify eligible studies. Search terms included “acetaminophen,” “aspirin,” “nonsteroidal anti-inflammatory agents,” or “NSAID” combined with “bladder cancer,” “bladder neoplasms,” or “bladder carcinoma”. The titles and abstracts of the studies identified in the search were scanned to exclude any clearly irrelevant studies. The full texts of the remaining articles were read to determine whether they contained information on the topic of interest. Furthermore, we also manually searched the reference lists of every article retrieved and review papers to find any additional published studies. All searches were conducted independently by 2 authors (HZ and DJ). The results were compared, and any questions or discrepancies were resolved through iteration and consensus.To be eligible, studies had to fulfill the following 4 inclusion criteria: 1) had a case-control or prospective study design; 2) reported results on aspirin, non-aspirin NSAIDs or acetaminophen use; 3) the outcome was bladder cancer incidence or mortality; and 4) reported the estimate of relative risk (RR) with their corresponding 95% confidence interval (CI) . Studies reporting different measures of RR like risk ratio, rate ratio, hazard ratio (HR), and odds ratio (OR) were included in the meta-analysis. In practice, these measures of effect yield a similar estimate of RR, since the absolute risk of bladder cancer is low.Data abstraction was conducted independently by 2 researchers (HZ and DJ), with disagreements resolved by consensus. The following information were collected: the first author’s last name, year of publication, country in which the study was performed, study design, years of follow-up or the study period, study participants age range, number of subjects and number of bladder cancer cases, used drugs, exposure definition, information source, control of confounding factors by matching or adjustment, and RR estimates with corresponding 95% CIs. If a study provided several risk estimates, the most completely adjusted estimate was extracted. Differences in data extraction were resolved by consensus, referring back to the original article.Separate analyses were performed according to use of acetaminophen, aspirin, and non-aspirin NSAIDs. Study-specific risk estimates were extracted from each article, and log risk estimates were weighted by the inverse of their variances to obtain a pooled risk estimate. We pooled study-specific log RRs to compute an overall RR and its 95% CI for regular/any use versus reference group from each study. For reference group, it was defined as “subjects who never took analgesics or who were not regular takers”. Where data for different intake levels or different duration of use were available, we subsequently restricted the analyses to the highest intake or the longest duration given by each study. Studies were combined by using the DerSimonian and Laird random-effects model, which considers both within- and between-study variations 2I statistic that estimates the percentage of total variation across studies due to heterogeneity rather than chance P value <0.10 was considered statistically significant for heterogeneity; for 2I, a value >50% is considered a measure of severe heterogeneity. When statistical heterogeneity was detected, sensitivity analyses were performed. Publication bias was evaluated with Egger’s regression test in which P value less than 0.10 was considered representative of statistically significant publication bias Statistical heterogeneity among studies was assessed using the Cochrane’s Q statistic, and inconsistency was quantified with the The detailed steps of our literature search are shown in The 17 relevant studies were published between 1985 and 2012, including 8 cohort studies P = 0.38 (Q = 9.70), and the corresponding quantity 2I was 7.3%, both indicating that the results of those studies were homogeneous. The P value for the Egger test was P = 0.23, suggesting a low probability of publication bias. The associations of acetaminophen use with bladder cancer risk did not differ by study type . The Egger test showed no evidence of publication bias for aspirin (P = 0.686). The associations of aspirin use with bladder cancer risk did not differ by study type , and the RR was essentially unchanged .To explore the heterogeneity among studies of aspirin use and bladder cancer, we performed sensitivity analyses. By using a stepwise process, we determined that most of heterogeneity was accounted for the study by Fortuny et al High intake or long duration of aspirin use was also not associated with bladder cancer risk . In addiP<0.001, 2I = 79.3%). The Egger test showed no evidence of publication bias for aspirin (P = 0.118). And we found that non-aspirin NSAIDs use was statistically significantly associated with reduced risk of bladder cancer among case-control studies, but not among cohort studies , and a significant association was observed .To explore the heterogeneity, we also performed the sensitivity analyses. By using a stepwise process, we determined that most of heterogeneity was accounted for the study by Sørensen et al In addition, stratified analysis by smoking status found that non-aspirin NSAIDs use was statistically significantly associated with 43% reduced risks of bladder cancer among nonsmokers , but not among current smokers  . And we This present meta-analysis included 17 studies (8 cohort and 9 case-control studies), involving a total of 10,618 bladder cancer cases. In this meta-analysis of the 3 most commonly used analgesics and bladder cancer risk, we found that acetaminophen and aspirin were not associated with bladder cancer risk. Although non-aspirin NSAIDs was statistically significantly associated with reduced risk of bladder cancer among case-control studies (but not cohort studies), the overall risk was not statistically significant. Also, non-aspirin NSAIDs was significantly associated with a 43% reduction in bladder cancer risk among nonsmokers.We found that acetaminophen use was not associated with the risk of bladder cancer with a pooled RR = 1.01 from 10 studies. Acetaminophen is a metabolite of phenacetin, a well-known banned carcinogen which has been more so linked to renal pelvic tumor In our meta-analysis, we did not found that aspirin use was associated with bladder cancer risk from 11 studies. Our results are in agreement with a large randomized controlled trial We found from 6 studies that non-aspirin NSAIDs use was not associated with the risk of bladder cancer in general. Nevertheless, there was significant heterogeneity by study. After excluding the study by Sørensen et al Furthermore, an interest finding in our meta-analysis, although more limited, is that smoking status might modify the association of use of nonaspirin NSAIDs with bladder cancer risk. Smoking is a well-known risk factor for bladder cancer. There are over 60 carcinogens, including nitrosamines, aromatic amines, and polycyclic aromatic hydrocarbons, have been detected in cigarette smoke. Metabolic activation of these carcinogens leads to the formation of DNA adducts, causing miscoding and other mutations Our study has several strengths: it is the most up-to-date comprehensive review of analgesics on one specific type of cancer, bladder cancer. It includes the 3 mostly used contemporary drugs and 17 observational studies were included in our meta-analysis, reporting data of more than 1 million participants, including 10,618 bladder cancer patients. Meta-analysis of studies with large numbers of incident cases provides high statistical power for estimating the relationship between exposure and outcome risk. Moreover, in a meta-analysis of published studies, publication bias could be of concern since small studies with null results tend not to be published. In this meta-analysis, however, we found little evidence of publication bias.Nevertheless, several limitations are worth mentioning. First, a meta-analysis is not able to solve problems with confounding factors that could be inherent in the included studies. Inadequate control for confounders may bias the results in either direction, toward exaggeration or underestimation of risk estimates. However, most observational studies in this meta-analysis adjusted for other known and potential risk factors for bladder cancer. Second, heterogeneity may be introduced because of methodologic and demographic differences among studies. We used appropriate well-motivated inclusion criteria to maximize homogeneity, and performed sensitivity and subgroup analyses to investigate potential sources of heterogeneity. Third, studies used different definition of analgesic use, which might have limited comparability of the results across the studies. However, our findings were stable and robust in the subgroup analyses. Fourth, long-term analgesic users may switch the type of analgesics they use over time. Because almost all of the studies assessed analgesics use at baseline only, we were not able to evaluate the impact of change of use of analgesics. In addition, the study does not clearly distinguish between multiple exposures to analgesics. The possibility of confounding would be especially relevant for long duration users, as those patients could have used phenacetin many years previously. Last, because of lack of data, it was not possible to address the important issues of dose and duration of use needed to achieve effects.In summary, the results of this meta-analysis of 17 observational studies indicated that use of acetaminophen, aspirin or non-aspirin NSAIDs was not associated with bladder cancer risk. However, non-aspirin NSAIDs use might be associated with a reduction in risk of bladder cancer for nonsmokers.Checklist S1PRISMA Checklist for the meta-analysis.(DOC)Click here for additional data file.