The mouse double minute 2 (MDM2) gene encodes a phosphoprotein that interacts with P53 and negatively regulates its activity. The SNP309 polymorphism (T-G) in the promoter of MDM2 gene has been reported to be associated with enhanced MDM2 expression and tumor development. Studies investigating the association between MDM2 SNP309 polymorphism and colorectal cancer (CRC) risk reported conflicting results. We performed a meta-analysis of all available studies to explore the association of this polymorphism with CRC risk.All studies published up to July 2013 on the association between MDM2 SNP309 polymorphism and CRC risk were identified by searching electronic databases PubMed, EMBASE, and Chinese Biomedical Literature database (CBM) databases. The association between the MDM2 SNP309 polymorphism and CRC risk was assessed by odds ratios (ORs) together with their 95% confidence intervals (CIs).A total of 14 case-control studies including 4460 CRC cases and 4828 controls were identified. We did not find a significant association between the MDM2 SNP309 polymorphism and CRC risk in all genetic models in overall population. However, in subgroup analysis by ethnicity, significant associations were found in Asians  and Africans. When stratified by HWE in controls, significantly increased risk was also found among the studies consistent with HWE . In subgroup analysis according to p53 mutation status, and gender, no any significant association was detected.The present meta-analysis suggests that the MDM2 is a candidate gene for CRC susceptibility. The MDM2 SNP309 polymorphism may be a risk factor for CRC in Asians. Colorectal cancer (CRC) is one of the most common forms of cancer and is the third leading cause of cancer-related death worldwide . In EuroThe murine double minute-2 (MDM2), a key negative regulator of the P53 tumor suppressor pathway, has been suggested to be implicated in a variety of cancers . EvidencOver the last two decades, a number of molecular epidemiological studies have been conducted to investigate the association between the MDM2 SNP309 polymorphism and CRC risk, but the results remain inconsistent. In addition, previous two meta-analyses on this issue also generated conflicting results ,12. SmalThis study was performed according to the proposal of Meta-analysis of Observational Studies in Epidemiology group (MOOSE) . We condStudies included in the meta-analysis were required to meet the following criteria: (1) Case–control studies which evaluated the association between MDM2 SNP309 polymorphism and CRC risk; (2) used an unrelated case–control design; (3) had an odds ratio (OR) with 95% confidence interval (CI) or other available data for estimating OR (95% CI); and (4) control population did not contain malignant tumor patients. Conference abstracts, case reports, editorials, review articles, and letters were excluded.Two reviewers (Xue Qin and Qiliu Peng) independently reviewed and extracted data from all eligible studies. Data extracted from eligible studies included the first author, year of publication, country of origin, ethnicity, genotyping method, matching criteria, source of control, CRC diagnosis criteria, total numbers of cases and controls and genotype frequencies of cases and controls. Ethnic backgrounds were categorized as Caucasian, Asian, and African. When a study did not state the ethnic descendent or if it was not possible to separate participants according to such phenotype, the group reported was termed as “mixed ethnicity”. To ensure the accuracy of the extracted information, the two investigators checked the data extraction results and reached consensus on all of the data extracted. If different results were generated, they would check the data again and have a discussion to come to an agreement. A third reviewer (Li Shan) was invited to the discussion if disagreement still existed.Methodological quality was independently assessed by two reviewers (Xue Qin and Qiliu Peng), according to a set of predefined criteria  based onp value of less than 0.05 was considered significant. We assessed the association of MDM2 SNP309 polymorphism with CRC risk using additive models (GG vs. TT and TG vs. TT), recessive model (GG vs. TG+TT), and dominant model (GG+TG vs. TT).The strength of the association between MDM2 SNP309 polymorphism and CRC risk was measured by odds ratios (ORs) with 95% confidence intervals (CIs). The significance of the pooled OR was determined by Z test and a Q test and I2 statistics were used to assess the statistical heterogeneity among studies [Q test was PQ < 0.1, indicating the presence of heterogeneity, a random-effects model (the DerSimonian and Laird method) was used to estimate the summary ORs [Q test was PQ ≥ 0.1, indicating the absence of heterogeneity, the ﬁxed-effects model (the Mantel–Haenszel method) was used [The  studies ,16. If tmary ORs ; otherwiwas used . To explp values were two-sided. To ensure the reliability and the accuracy of the results, two authors entered the data into the statistical software programs independently with the same results.Sensitivity analysis was performed by sequential omission of individual studies. Publication bias was evaluated using a funnel plot and Egger’s regression asymmetry test . If publBased on our search criteria, 242 individual records were found, but only 17 full-text publications were preliminarily identified for further detailed evaluation . AccordiAs shown in PQ = 0.000; GT vs. TT: PQ = 0.000; GG+ GT vs. TT: PQ = 0.000; GG vs. GT+ TT: PQ = 0.000; PQ = 0.000; GG+ GT vs. TT: PQ = 0.046; GG vs. GT+ TT: PQ = 0.000; I2 values decreased obviously and PQ values were greater than 0.10 after excluding the two studies Liu et al. [PQ = 0.172; GT vs. TT: PQ = 0.297; GG+ GT vs. TT: PQ = 0.280; GG vs. GT+ TT: PQ = 0.185), Asians , and studies consistent with HWE . The signiﬁcance of the summary ORs for MDM2 SNP309 polymorphism in different comparison models in the overall population and subgroup analyses were not inﬂuenced by omitting the two studies.Significant heterogeneity was observed in the association analysis between the MDM2 SNP309 polymorphism and CRC risk in the overall populations in all comparisons . To find the sources of heterogeneity, we performed metaregression and subgroup analyses. Metaregression analysis of data showed that the ethnicity was the major source which contributed to heterogeneity. The Genotyping methods, Source of control, Quality scores, and CRC diagnosis were not effect modifiers. Subgroup analysis by ethnicity showed that the heterogeneity was still significant in Asians. To further investigate the heterogeneity, Galbraith plots analysis was performed to identify the outliers which might contribute most to the heterogeneity. Our results showed that the studies of Liu et al. [I2 values decreased lower than 50% and PQ values were larger than 0.10 after excluding the studies of Liu et al. [Heterogeneity is a potential problem when interpreting the results of a meta-analysis, and finding the sources of heterogeneity is one of the most important goals of meta-analysis . In the u et al.  and Chaau et al.  were outu et al.  and Chaau et al.  in all gSome possible limitations in this meta-analysis should be acknowledged. Firstly, in subgroup analysis by ethnicity, p53 mutation status, and gender, the sample size of population was relatively small for stratified analyses, which may lead to relatively weak power to detect the real relationship. Secondly, our results were based on unadjusted estimates. We did not perform the analysis adjusted for other covariates such as age, drinking status, cancer type, environment factors, and so on, because of the unavailable original data of the eligible studies.In conclusion, our meta-analysis provided a more precise estimation based on larger sample size compared with the previous meta-analyses. Our study suggested that the MDM2 SNP309 polymorphism might contribute to CRC risk, especially in Asian populations. In order to further verify our findings, large well-designed epidemiological studies are warranted.Checklist S1PRISMA checklist.(DOC)Click here for additional data file.Figure S1Flow diagram of included studies for this meta-analysis.(TIF)Click here for additional data file.


There is some controversy regarding the effect of opium addiction on the coronary artery disease (CAD). The aim of this study was to determine the association between chronic opium consumption and CAD.This study had a case-control design. The patients recruited to the study were selected from angiography files in Department of Cardiology in Kerman University of Medical Sciences, Kerman, Iran. The comparison was done between CAD patients and normal subjects. Opium addiction was diagnosed by patient self-report and confirmed with interview based on DSM-IV criteria. Odds ratio with 95% confidence interval were estimated by unconditional logistic regression.The risk factor of CAD was the same in the two study groups. The significant difference in opium consumption was demonstrated between CAD patients and normal coronary artery subjects . Because of the strong association between cigarette smoking and opium addiction, analysis was done in smoker and non-smoker groups separately. Logistic regression showed opium addiction was the independent risk factor for CAD in non-smokers after adjusting to other CAD risk factors , but in cigarette smokers opium was not a significant risk factor .We confirmed that the opium was an independent risk factor for CAD. Health managers and policy makers should try to aware general population and prepare many preventive programs against substance abuse. Primary investigation on morphine and its derivatives had been focused on central nervous system (CNS), thoroughly. It has been determined that opioids have many effects on different physiological systems. In recent years, there are a great deal of interest on cardiovascular system because of the cardioprotective role of opioid endogenous and exogenous compounds on ischemic preconditioning (IPC).137st 2007. It included 137 cases till February 1st 2008. The nested case-control study was designed in the cohort study. We recruited the patients who were catheterized. Those cases with positive findings in catheterization were selected as case group and subjects with normal angiography were included in the control group. The research proposal was approved by both research and medical ethics committees in Kerman University of Medical Sciences.The study was conducted in Department of Cardiology and Angiography in Shafa Medical Center, one of the biggest hospitals of Kerman University of Medical Sciences. The angiography ward is the only cath lab in Kerman province. We carried out a cohort study of chest pain in our department since February 1Demographic and cardiovascular risk factor information  and angiographic data were collected by reviewing the patients’ records. Besides, opium addiction was diagnosed by patient self-report and confirmed with interview based on DSM-IV criteria. Type of substance abuse, duration of abuse and kind of consumption were recorded in interview. All data were registered in structured data collection forms.Data was compared between the two CAD positive and negative groups. The chi-square test was used for analysis of nominal variables. The mean was compared with t test and when it was ranked, the Mann-Whitney test was appropriated. Odds ratio and confidence interval was calculated for every risk factor and tested with Mantel-Haenszel test. The roles of established CAD risk factors as effect modifiers or confounders were evaluated by stratification and were finally considered in the logistic regression models. The analyses were performed by using the SPSS release for Windows, Version 15 . The P<0.05 was considered significant.Of 137 cases in our cohort, 91 patients were catheterized and recruited. CAD was delineated in 58 (63.7%) patients; 33 (36.3%) had normal angiography.The risk factors and demographic characteristics were the same in addicted CAD patients and those with normal coronary artery . The metThe results of current study revealed that the frequency of opium addiction in CAD patients was greater than that in normal ones (58.6% vs. 27.3%). However, after adjusting with other risk factors and stratifying based on cigarette smoking because of the great association between opium addiction and cigarette smoking, logistic regression model determined that in non-smokers opium addiction was the independent risk factor for CAD with OR=38 (95%CI=2.7-531.7). In contrast, although the OR was equal to 13.2 in smokers, the difference was not significant (95%CI=0.85-206.5). The opium addiction in our country, Iran, is a very dramatic public health problem. On the other hands, the mortality and morbidity due to CAD is located on the top of the mortality and morbidity list in Iran; many investigators attempt to find the association between opium, CAD and atherosclerosis phenomenon. Previous studies have shown that the range of opium addiction is varied from 10% in coronary artery bypass graft patients


MTNR1B and T2D has been reported in various ethnic groups. The aim of this study was to consolidate and summarize published data on the potential of MTNR1B polymorphisms in T2D risk prediction.Melatonin receptor 1B (MTNR1B) belongs to the seven-transmembrane G protein-coupled receptor superfamily involved in insulin secretion, which has attracted considerable attention as a candidate gene for type 2 diabetes (T2D) since it was first identified as a loci associated with fasting plasma glucose level through genome wide association approach. The relationship between PubMed, EMBASE, ISI web of science and the CNKI databases were systematically searched to identify relevant studies. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated. Heterogeneity and publication bias were also tested.MTNR1B were included. An overall random effects per-allele OR of 1.05  and 1.04  were found for the two variants respectively. Similar results were also observed using dominant or recessive genetic model. There was strong evidence of heterogeneity, which largely disappeared after stratification by ethnicity. Significant results were found in Caucasians when stratified by ethnicity; while no significant associations were observed in East Asians and South Asians. Besides, we found that the rs10830963 polymorphism is a risk factor associated with increased impaired glucose regulation susceptibility.A total of 23 studies involving 172,963 subjects for two common polymorphisms  on This meta-analysis demonstrated that the rs10830963 polymorphism is a risk factor for developing impaired glucose regulation and T2D. Glucose homeostasis in healthy individuals is tightly controlled through a complex pathway of regulatory mechanisms involving multiple organs and tissues. Disruption of normal glucose homeostasis and substantial elevations of fasting glucose are hallmarks of type 2 diabetes (T2D) and typically result from sustained reduction in pancreatic beta-cell function and insulin secretion. However, there is substantial variation in fasting glucose levels even within healthy, non-diabetic populations. Approximately one-third of this variation is genetic MTNR1B and risk of T2D as well as to quantify the between-study heterogeneity and potential bias.Recent genome-wide association studies (GWAS) and meta-analysis have identified genes contributing to the variation of fasting plasma glucose (FPG) levels in populations of European origin MTNR1B gene were identified through a search of PubMed, Web of Science, EMBASE and CNKI . Search term were keywords relating to the relevant gene (e.g. ‘melatonin receptor 1B’ or ‘MTNR1B’) in combination with words related to T2D (e.g. ‘Type 2 diabetes’ or ‘Type 2 diabetes mellitus’ or ‘non-insulin dependent diabetes mellitus’). Furthermore, reference lists of main reports and review articles were also reviewed by a manual search to identify additional relevant publications.Genetic association studies published before the end of May 2012 on T2D and polymorphisms in the P-value;, (4) case–control or cohort studies. The major reasons for exclusion of studies were (1) overlapping data and (2) case-only studies, family based studies, and review articles.The included studies have to meet the following criteria: (1) original papers containing independent data which have been published in peer-reviewed journal, (2) identification of T2D patients according to the World Health Organization criteria, American Diabetes Association criteria, or other standard criteria, (3) genotype distribution information or odds ratio (OR) with its 95% confidence interval (CI) and Data extraction was performed independently by two reviewers and differences were resolved by further discussion among all authors. For each included study, the following information was extracted from each report according to a fixed protocol: first author, publication year, definition and numbers of cases and controls, diagnostic criterion, impaired glucose regulation (IGR) status (impaired fasting glucose and/or impaired glucose tolerance), frequency of genotypes, age, sex, body mass index (BMI), Hardy–Weinberg equilibrium status, ethnicity and genotyping method.2 tests. Odds ratio (OR) with 95% confidence intervals (CIs) was used to assess the strength of association between the MTNR1B gene polymorphism and T2D risk. The per-allele OR of the risk allele was compared between cases and controls. Then, we examined the association between risk genotype of these polymorphisms and T2D susceptibility using dominant and recessive genetic models. Heterogeneity across individual studies was calculated using the Cochran chi-square Q test followed by subsidiary analysis or by random-effects regression models with restricted maximum likelihood estimation Deviation from Hardy–Weinberg equilibrium for controls was examined by χSensitivity analyses were performed to assess the stability of the results, namely, a single study in the meta-analysis was deleted each time to reflect the influence of the individual data set to the overall OR. Publication bias was assessed using Egger's test MTNR1B polymorphisms The combined search yielded 72 references. Forty-nine articles were excluded because they clearly did not meet the criteria or overlapping references. Finally, a total of 23 studies were retrieved based on the search criteria for T2D susceptibility related to the P(Z)<10−4, P(Q) = 0.01; P(Z)<10−4, P(Q) = 0.17 ] and 1.12 , respectively. In the stratified analysis by ethnicity, significantly increased risks were found among Caucasian populations . However, no significant association was found for East Asian and South Asian populations in all genetic models (P(Z) = 0.32, P(Q) = 0.15] in small studies compared to 1.06  in larger studies.Overall, there was evidence of an association between the increased risk of T2D and the variant in different genetic models when all the eligible studies were pooled into the meta-analysis. Using random effect model, the summary per-allele OR of the G variant for T2D was 1.05  and recessive  genetic model. This analysis is based on pooling of data from a number of different ethnic populations. When stratifying for ethnicity, an OR of 1.21  and 1.13  resulted for risk allele, among Caucasians and East Asians, respectively (P(Z) = 0.66; P(Q)<10−4] for IGT compared to 1.33  for IGF.To investigate how glucose metabolism was related to ectively . By consMTNR1B rs1387153 and T2D. The overall OR for risk T allele was 1.04 . However, no significant association was found for East Asian and South Asian populations in almost all genetic models (P(Z) = 0.57] for small studies and for larger studies of 1.07 .The meta-analysis resulted in a statistically non-significant association between c models . SubsidiP = 0.37), ethnicity (P = 0.46), mean BMI of cases (P = 0.17) and controls (P = 0.29), mean age of cases (P = 0.09) and controls (P = 0.67), nor sex distribution in cases (P = 0.39) and controls (P = 0.11) were significantly correlated with the magnitude of the genetic effect.In meta-regression analysis, neither sample size  locus increases the level of FPG. However, the relationship between these common variations and T2D susceptibility has not been built up yet. This is the first comprehensive meta-analysis examined the MTNR1B polymorphisms  and the relationship to T2D risk. Its strength was based on the accumulation of published data giving greater information to detect significant differences. In total, the present meta-analysis combined 23 studies including 48, 278 T2D cases, 10,810 IGR cases, and 119,960 controls.Large sample and unbiased epidemiological studies of predisposition genes polymorphisms could provide insight into the in vivo relationship between candidate genes and diseases. GWAS and meta-analysis have shown that common variation in the MTNR1B is a risk factor for developing type 2 diabetes. In the stratified analysis by ethnicity, significant associations were found in Caucasians for the polymorphism in all genetic models. However, no significant associations were detected among East Asian and South Asian populations for rs10830963 and rs1387153 polymorphisms. There are several possible reasons for such differences. Firstly, the frequencies of the risk-association alleles in MTNR1B vary between different races. For example, the G allele distributions of the rs10830963 polymorphism varies between East Asian, South Asian and Caucasian populations, with a prevalence of ∼42%, ∼39%, and ∼25%, respectively. Therefore, additional studies are warranted to further validate ethnic difference in the effect of these polymorphisms on TD risk. Secondly, such different results could also be explained by study design or sample size. Besides, other confounding factors, such as age, sex, life style should also be considered. In the stratified analysis according to sample size, significantly associations were found only found for larger studies. Thus, absence of association with type 2 diabetes in small study could be due to insufficient power. Thus, for future association studies much larger sample size will be required.Our results demonstrated that the rs10830963 polymorphism of Melatonin is mainly produced by the pineal gland but is also released from the gastrointestinal tract MTNR1B that are associated with T2D was also conferred the risk of IGR. Our study suggested that IGR might have similar background of susceptible genetic variations. In addition, our results indicated that significantly increased risk of MTNR1B rs10830963 polymorphism was found for IGF but not for IGT when stratified by IGR outcome. However, because the IGR included IFG and IGT which may have different genetic etiology Impaired glucose regulation (IGR) includes impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT). IGR is also known as intermediate hyperglycemia or pre-diabetes and characterized by high blood glucose concentrations, insulin resistance and impaired insulin secretion. Previous studies have shown that 5∼10% IGT subjects developed diabetes each year, although, some of them could revert spontaneously to normal glucose tolerance In interpreting the results, some limitations of this meta-analysis should be addressed. Firstly, the subgroup meta-analyses on Asian populations are based on a small number of studies with such information available. Nevertheless, the total number of subjects included in this part of the analysis comprises the largest sample size so far. As studies among the Non-Caucasians are currently limited, further studies including a wider spectrum of subjects should be carried to investigate the role of these variants in different populations. Secondly, our results were based on unadjusted estimates, while a more precise analysis should be conducted if all individual raw data were available, which would allow for the adjustment by other co-variants including age, drinking status, obesity, cigarette consumption, and other lifestyle. Thirdly, heterogeneity is a potential problem when interpreting all the results of meta-analysis. Although we minimized the likelihood by performing a careful search for published studies, using the explicit criteria for study inclusion, the significant between-study heterogeneity still existed in most of comparison. Besides, subgroup analysis and meta-regression were also used to identify the source of heterogeneity. The presence of heterogeneity can result from differences in the age distribution, obesity status of subjects, selection of controls, dietary habits, prevalence lifestyle factors and so on. Last but not least, only published studies were included in this meta-analysis. Therefore, publication bias may have occurred, even though the use of a statistical test did not show it.MTNR1B rs10830963 polymorphism was significantly associated with increased risk of T2D, particularly in the Caucasian population. In addition, our meta-analysis results suggest that MTNR1B rs10830963 is risk factor for the development of impaired glucose regulation. Moreover, gene–gene and gene–environment interactions should be considered in future studies.To conclude, this meta-analysis showed that the Checklist S1(DOC)Click here for additional data file.Figure S1Study selection process.(TIF)Click here for additional data file.Figure S2Result of sensitivity analyses for MTNR1B rs10830963.(TIF)Click here for additional data file.Figure S3Result of sensitivity analyses for MTNR1B rs1387153.(TIF)Click here for additional data file.Figure S4Begg's funnel plot of MTNR1B rs10830963 polymorphism and T2D risk.(TIF)Click here for additional data file.Figure S5Begg's funnel plot of MTNR1B rs1387153 polymorphism and T2D risk.(TIF)Click here for additional data file.Figure S6Test publication bias of studies of the rs10830963 polymorphism of MTNR1B and T2D using Egger test.(TIF)Click here for additional data file.Figure S7Test publication bias of studies of the rs1387153 polymorphism of MTNR1B and T2D using Egger test.(TIF)Click here for additional data file.


MTRR) and Methionine synthase (MTR) are key enzymes involved in the metabolic pathway of homocysteine, which are significant in the earlier period embryogenesis, particularly in the cardiac development. Evidence is mounting for the association between MTRR A66G (rs1801394)/MTR A2756G (rs1805087) and the CHD risk, but results are controversial. Therefore, we conducted a meta-analysis integrating case-control and transmitted disequilibrium test (TDT) studies to obtain more precise estimate of the associations of these two variants with the CHD risk.Congenital heart disease (CHD) is one of the most common birth defects and the leading cause of deaths among individuals with congenital structural abnormalities worldwide. Both Methionine synthase reductase  and 95% confidence intervals (CIs).MTRR A66G polymorphism; and 4 reports comprised of 250 cases, 205 controls, and 53 families that were relevant to MTR A2756G polymorphism. The pooled OR for the MTRR 66 G allele versus A allele was 1.35 . For MTR A2756G, the G allele conferred a pooled OR of 1.10  compared with the A allele. Sensitivity analyses were carried out to asses the effects of each individual study on the pooled OR, indicating the stability of the outcome. Moreover, positive results were also obtained in all subgroups stratified by study type and ethnicity except the subgroup of TDT studies in MTRR A66G variant.A total of 9 reports were included in the final meta-analysis. Eight of them comprised of 914 cases, 964 controls, and 441 families that were germane to MTRR, but not the A2756G in MTR, may be associated with the increase of CHD risks.This meta-analysis demonstrated a suggestive result that the A66G variant in  Congenital heart disease (CHD), an abnormality in the heart's structure or function that arises before birth 9, plays an important role during embryologic development, has been shown to prevent CHD during pregnancy MTRR and MTR, folic acid aid in converting homocysteine into methionine. It is widely accepted that the occurrence of CHD relies not only on the insufficiency of folic acid Current knowledge on susceptibility, as well as pathological mechanism underlying the development of CHD has indicated a multiple exposure interaction between genetic and environmental factors MTR) and methionine synthase reductase (MTRR), major regulatory enzymes involved in homocysteine metabolic pathway, map to chromosomes 1q43 and 5p15.31 respectively. MTR catalyzes the remethylation of homocysteine to form methionine, which is the decisive step in methionine biosynthesis MTRR is responsible for activating methionine synthase via reductive methylation modulating a functional deficiency of methionine synthase when MTRR activity is disrupted MTRR A66G (rs1801394) and MTR A2756G (rs1805087) were discussed mostly as a genetic cause of CHD in humans. MTRR A66G polymorphism results in an isoleucine-to-methionine substitution, whose biochemical phenotypes alter the affinities for the redox partner—methionine synthase. Likewise, MTR A2765G is a missense mutation causing a codon of aspartate substituted by a glycine residue. Methionine synthase  and text words, without language restriction. We also conducted a comprehensive manual check on the reference lists of retrieved articles.We searched the relevant literatures from Medline, ISI Web of Science, China National Knowledge Infrastructure (CNKI) and Sinomed databases before March 1, 2013. The following key words were used: “MTRR A66G or MTR A2756G polymorphism and the risk of CHD; (2) the study provided necessary data to calculate odds ratios (ORs) and 95% CIs. Reviews, case reports, comments, unpublished reports and duplicate data were excluded.Studies eligible for inclusion in our meta-analysis have to fulfill the following criteria: (1) the study was a case-control or a TDT design with human subjects that illustrated the relationships between All data were independently extracted by two reviewers (B. Cai and T. Zhang). The following informations were extracted or calculated from the eligible studies: First author, publication year, country, ethnicity, design type of study, the number of case and controls or families, frequencies of alleles of case and control group in case-control study or the frequency of alleles transmitted from heterozygous parents to affected offspring in TDT. All disagreements were resolved by discussion.MTRR A66G and MTR A2756G polymorphisms and the risk of CHD. Effect estimates were pooled using a random-effect model, and statistical heterogeneity was measured by estimating the I-squared statistic and also by implementing the Q-test; heterogeneity was considered present when P<0.10. To combine case-control and TDT studies, Kazeem and Farrall http://www.r-project.org). Sensitivity analysis was performed by omitting one study at a time and recalculating the pooled OR for the remaining studies to assess the influence of each study We utilized the ORs and 95% CIs to examine the strength of associations between P- values<0.05 were assumed significant.All statistical analyses were conducted using Catmap software V1.6, and MTR or MTRR and CHD risk were rejected. Among the remaining 16 papers, 5 were eliminated because of the unmatched gene loci and the studies reported by Christensen et al. MTRR A66G polymorphism including 914 cases, 964 controls and 441 families, and 4 reports were relevant to MTR A2756G polymorphism including 250 cases, 205 controls and 53 families. Of these 9 studies, 4 were conducted in Chinese Han, 2 in Europeans, 1 in Iranians and 2 in mixed ethnicity. All patients in these 8 studies were diagnosed based on echocardiography and cardiac catheterization. Besides, 5 and 1 studies involved all types of CHDs or specific type VSD of CHDs separately, and the rest of the studies lack of related information. MTRR A66G in association with CHD. A random-effect model was employed  = 45.9) and statistical evidence indicated that the G allele of MTRR A66G was associated with increased risk of CHD .MTRR A66G may be associated with the increased risk of CHD (MTRR (P = 0.291).Additionally, we conducted a sensitive meta-analysis to assess the effect of each individual study on the combined OR. A series of combined ORs with 95% CIs produced repeatedly after removal of each particular study consistently exceeded 1.0, suggesting the stability of the outcome that the G allele of k of CHD . What's k of CHD  and no p2 = 4.99, Pheterogeneity = 0.173, I2 (%)  = 39.8) and there was no statistical evidence of an association between MTR A2756G polymorphism and the CHD risk . The sensitivity analysis , there was no significant publication bias.As shown in analysis  demonstrnnel plot and the MTRR A66G polymorphism, evidence of heterogeneity was found in the case-control studies  = 68.8), but not in the TDT studies  = 7.4). The pooled allelic ORs were 1.64  in the case-control studies and 1.17  in TDT studies, respectively.The stratified analysis was first performed by study design . For the2 = 6.95, Pheterogeneity = 0.074, I2(%) = 56.8), but not in the other subgroup  = 50.0). The association between MTRR A66G and the CHD risk was found in both subgroups .These data were further stratified by ethnicity into 2 subgroups: the Chinese and the non-Chinese subgroups . StratifMTR A2756G polymorphism, the stratified analysis could not be conducted due to lack of studies.In terms of the subtype of CHD, the pooled ORs specific to each subtype could not be estimated due to limited data. Regarding MTRR/MTR variants and the risk of CHD. The results of this study may be indicative of a association between MTRR A66G variant and the CHD risk . In addition, the stability was well supported by the sensitivity analysis. Heterogeneity was observed in the overall analysis and the stratified analysis on MTRR A66G indicating that the case-control study may be one of the potential sources of heterogeneity. This meta-analysis also integrated studies on MTR A2756G, however, no significant evidence was found.As far as we know, our meta-analysis first integrated the case-control and TDT studies to provide important insights into the association between MTR gene located at chromosome 1q43, encoding methionine synthase, which can transfer the methyl-group from 5mTHF to Hcyand produce MET(methionine) and THF (tetrahydrofolic acid) by means of remethylation MTRR gene, located on chromosomes 5p15.31, encodes methionine synthase reducate, playing a key role inactivating methionine synthase. Thus, MTRR genetic defect might inhibit the development of the fetuses by changing the concentration of Hcy, 5mTHF, MET and THF A number of studies have demonstrated that genetic defects of these enzymes will trigger folic acid metabolic disorders, which may lead to CHD. The vast network of folic acid metabolism involves the interaction of various enzymes, requiring effective coordination of folic acid and vitamin B, which affects the folate pathway through regulation of multiple metabolism processes. MTRR A66G variant MTRR A66G and the risk of CHD. Zeng et al. MTRR A66G was associated with a 1.5-fold increased risk of CHD and Pishva et al. Despite that no significant evidence was found in the first literature on MTRR A66G variant and the increased risk of CHD , supporting the results in former observations MTRR A66G was relatively robust in different ethnic groups, especially in Chinese Han. However, due to the small sample size of other ethnicities except Han, separate stratified analysis for each ethnicity was not feasible. Besides, no reversed results were detected in the sensitivity analysis, which showed the stability of our study.Our meta-analysis gathered 8 reports including 914 cases, 964 controls and 441 families which indicated a suggestive association between the MTRR A66G polymorphism, we conducted a comprehensive stratified analysis and sensitive analysis. There was no indication of heterogeneity among TDT studies  = 7.4) when studies were grouped according to the study design, coinciding with the result of sensitive analysis, after we omitted four case-control studies 2 = 9.55, Pheterogeneity = 0.023, I2 (%) = 68.8) and the subgroup of non-Chinese  = 56.8) indicated that the heterogeneity of the effects of the MTRR A66G across association studies may due to the differences in ethnicity and the variety of participant selection and study design in different studies. However, the small sample sizes limited us to eliminate these studies to perform further analysis. Furthermore, sensitivity analysis and the publication bias assessment indicated that the current results of MTRR A66G in this meta-analysis were robust.Moreover, to explore the sources of between-study heterogeneity in MTR A2756G and the risk of CHD was observed in our meta-analysis . Since the genotype is of low frequency in most populations with small effect sizes, limited sample sizes may lead to instability of the results and greater variety between studies. Additionally, since CHD is a multiple etiology disease, we cannot exclude the potential influence of gene-gene and gene-environment interaction with a relatively small sample size. The sensitivity analysis also demonstrates that the result of current meta-analysis was unstable.No significant evidence of correlation between P values, we combined case-control and TDT studies in this meta-analysis. Although the statistical power increased by integrating case-control and TDT studies, some limitations should also be seriously considered. Firstly, mixed population of samples, distinct subtypes of CHD patients, diverse age range, female/male ratio, control matched condition in case-control design and multiplex or simplex trios utilized in TDT design may possibly affect the current result. Secondly, CHD is a complex trait caused by both genetic and environmental factors; lacking of environmental data limited our further evaluation of gene-environment interaction. Thirdly, the difference in the allelic frequency between individuals of different ethnic populations may be a confounding factor, which affected the efficacy of the results.In order to provide more powerful statistical evidence with robust ORs and Moreover, although the recent advances in genome-wide association study and subsequent replication studies MTRR A66G polymorphism might be associated with the risk of CHD. However, MTR A2756G failed to support an evidence of the association, and more studies with larger sample sizes concerning the association between the MTR/MTRR variants and CHD are required to confirm the current findings.In conclusion, our meta-analysis suggests that Checklist S1PRISMA checklist.(DOC)Click here for additional data file.


ABCB1 polymorphism and clopidogrel responding, but the results have been inconclusive. To examine the risk of high platelet activity and poor clinical outcomes associated with the ABCB1 C3435T polymorphism in CAD patients on clopidogrel, all available studies were included in the present meta-analysis.A number of investigators have evaluated the association between the We performed a systematic search of PubMed, Scopus and the Cochrane library database for eligible studies. Articles meeting the inclusion criteria were comprehensively reviewed, and the available data were accumulated by the meta-analysis.P = 0.003; TT vs. CC: OR, 1.77; 95% CI, 1.19 to 2.63; P = 0.005; CT + TT vs.CC: OR, 1.48; 95% CI, 1.06 to 2.06; P = 0.02) and the polymorphism was also associated with the risk of the long-term MACE in patients on clopidogrel LD 300 mg . The comparison of TT vs. CC was associated with a reduction in the outcome of bleeding . However, the association between ABCB1 C3435T polymorphism and platelet activity and other risk of poor clinical outcomes was not significant.It was demonstrated that the ABCB1 C3435T variation was associated with the risk of early major adverse cardiovascular events (MACE) (T vs. C OR, 1.34; 95% CI, 1.10 to 1.62; ABCB1 C3435T polymorphism might be a risk factor for the MACE in patients on clopidogrel LD 300 mg, and that TT homozygotes decreased the outcome of bleeding compared with CC homozygotes.The evidence from our meta-analysis indicated that the  Clopidogrel inhibits the adenosine-diphosphate-induced platelet aggregation, reducing the cardiovascular complications in patients with coronary atherosclerotic heart disease (CAD), especially in those undergoing percutaneous coronary intervention (PCI) ABCB1  gene encodes the intestinal efflux transporter P-glycoprotein, which modulates the absorption of clopidogrel ABCB1 gene locates at 7, p21–21.1 ABCB1 C3435T (rs1045642) is extensively studied and some research has been shown that the ABCB1 C3435T genotype influences the impaired function of P-glycoprotein which can hinder the absorption of clopidogrel The et al.ABCB1 C3435T polymorphism influenced ADP dependent platelet reactivity and showed that T-allele carriers were likely to have a poor response to antiplatelet therapy in the lab test. However, the results from different studies ABCB1 C3435T polymorphism and platelet activity as well as the risk of poor clinical outcomes in patients treated with clopidogrel.Antiplatelet response could be investigated through poor clinical outcomes and impaired response to antiplatelet therapy in the laboratory test. Simon ABCB1, MDR1, multidrug resistance, polymorphism). All eligible studies were retrieved and their bibliographies as well as the previous meta-analysis were checked for other relevant studies.Three electronic databases  were searched  availability of the genotype frequency on target population, and (5) the valid date, on publication or through corresponding by e-mail, to work out an odds ratio (OR) or P-value with 95% confidence interval (CI).The studies that met the following criteria were included: (1) published in English, (2) case- control studies on platelet activity and prospective cohort studies on clinical outcomes, (3) the evaluation of the Two reviewers independently extracted the data and reached a consensus on all items. The following information was achieved from each study: the first author’s name, publication date, ethnicity, population studied, characteristic of target population, treatment protocal,definition of cases, poor outcomes, study period and gene information, respectively.The two parts of endpoints  were studied. The poor clinical outcomes included major adverse cardiovascular events (MACE) which were composed of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, as well as all-cause mortality, MI, stroke, definite or probable stent thrombosis and major or minor bleeding.ABCB1 C3435T polymorphism and platelet activity as well as the poor clinical outcomes in patients who received clopidogrel. According to the method described by Woolf 2 - based Q statistic test, and regarded as significant if p value was less than 0.1 2 was used to efficiently test for the heterogeneity, with I2 less than 25%, 25–50%, and greater than 50% as low, moderate and high degree of inconsistency, respectively The observed genotype frequencies in controls or entire cohorts were tested to compare with the expected genotype frequencies by Hardy-Weinberg equilibrium (HWE). Crude odds ratio (OR) with 95% confidence interval (CI) in each study was used to assess the strength of association between P value was less than 0.05.Subgroup analyses were applied to identify the heterogeneity. Sensitivity analyses were conducted by sequential omission of individual studies respectively to detect the potential influence of each study set to the pooled ORs. In addition, publication bias was carried out by the funnel plot, and the symmetry of the plot distribution indicated the absence of publication bias ABCB1 C3435T polymorphism with respect to platelet activity and the poor clinical outcomes were found, of which 22 replicated studies were excluded. Additionally, 39 reviews, 1 meta-analysis and 3 studies not in English were excluded. Meanwhile, 29 irrelevant studies were excluded by reviewing the title and abstract and one trial A total of 113 studies on the ABCB1 C3435T variation was not significant , homozygote comparison  and dominant genetic model   .ABCB1 C3435T polymorphism in all genotype genetic models  had no significant association with ogeneity .ABCB1 C3435T polymorphism was further evaluated in stratification analyses. According to the clopidogrel loading dose, we found that this polymorphism was associated with the risk of the MACE in patients treated with clopidogrel LD 300 mg in allele comparison , homozygote comparison , and dominant genetic model  , homozygote comparison , and dominant genetic model , and the heterogeneity was low for all comparisons except for that of TT vs. CC + CT (I= 0.016) . The oveABCB1 C3435T polymorphism and risk of MI in the follow-up period  and recessive genetic model  . The summary ORs showed no association between  = 0.03) .ABCB1 C3435T polymorphism was unrelated to the rate of ischemic stroke in patients treated with clopidogrel . As described in ABCB1 C3435T variation was not significant  occurred during follow-up. When all eligible studies were pooled, the association between all-cause and the ABCB1 C3435T polymorphism in all genotype genetic models  . The cumulative incidence of stent thrombosis was not associated with  = 0.06) .P<0.00001; ABCB1 C3435T polymorphism and other genetic models as well as heterogeneity were identified (The bleeding rate in the five cohort studies was 7.82% (596 of the 7619). The comparison of TT vs. CC was associated with a significant reduction in the outcome of bleeding .In platelet activity studies, there was significant heterogeneity in three genetic contrasts of the 1 C3435T . HoweverABCB1 C3435T with long-term MACE  except one model , as well as clopidogrel LD 600 mg in two contrasts  except one model.Furthermore, significant heterogeneity existed in all the four genetic models of the erm MACE . But in 2 = 0%; P = 0.32) and the other (percentage >50%) .In addition, the heterogeneity existed in allele comparison with regard to stent thrombosis . When weAlthough we also found the heterogeneity in two genetic model contrasts of Myocadial infarction and one genetic model contrast of early MACE , due to ABCB1 C3435T dominant genetic model (CT + TT vs. CC). The significance of pooled ORs was not obviously affected by omission of individual studies except for MACE. One study et al.Sensitivity analysis was performed in the Funnel plot as well as Begg’s and Egger’s tests were carried out to access the publication bias of studies. Data showed that there was no evidence of publication bias in comparison of TT+TC vs. CC .ABCB1 C3435T had been revealed to be associated with loss of function of P-glycoprotein which decreased the active metabolite of clopidogrel. On the basis of antiplatelet responding in the laboratory test and poor clinical outcomes, several molecular cardiovascular studies were conducted to evaluate the association between the ABCB1 C3435T polymorphism and platelet response in CAD patients on clopidogrel, but the results were inconclusive. A former meta-analysis ABCB1 C3435T polymorphism and risk of short-term recurrent ischemic events.Clopidogrel, as a pro-drug, was known to require metabolic activation before inhibiting platelet aggregation. The et al.ABCB1 C3435T polymorphism and clopidogrel loading dose, which need further research to identify. Meanwhile another study In the present meta-analysis, since we included newer studies Four studies ABCB1 C3435T polymorphism and antiplatelet responding, we also should set our insights to the interaction between single-nucleotide polymorphisms (SNP) and other factors. As coexisting, rather than single, polymorphisms in different genes may be related to persistent platelet activation while on clopidogrel P2Y12 or CYP2C19 with ABCB1 C3435T, should also be observed between ABCB1 C3435T polymorphism and antiplatelet responding. On the other hand, one recent research ABCB1 C3435T genotype influenced the change of 20 µmol ADP-induced maximal platelet aggregation (MPA) in smoking status receiving clopidogrel. In our meta-analysis, the small scale of population and inconsistent stratification standards in environmental exposures and genotypes lowered our statistical power to further explore the gene-environment interaction. As a result, we need to give careful consideration to more sophisticated gene-gene and gene-environment interactions in a future analysis, so as to obtain a more comprehensive understanding of the association between ABCB1 C3435T polymorphism and antiplatelet responding.Clopidogrel inhibits the platelet activity, and high platelet activity in patients treated with Clopidogrel indicates clopidogrel resistance or poor response to clopidogrel, which will lead to poor clinical outcome in the future. Though we have found some association between ABCB1 in human epithelial colorectal (Caco-2) cells ABCB1 genotypes were not significantly associated with clinical or pharmacological outcomes in patients treated with prasugrel CYP2C19 and ABCB1 genotypes ABCB1 genotypes associated and gave us fresh insight to the antiplatelet treatment in addition to aspirin and clopidogrel, however numerous trails should be arranged for further assessment.Besides, from the different aspirin doses or triple antiplatelet therapy our studies included, we believe that interaction between gene and drug combination may also exist. Prolonged use of aspirin may reduce the intestinal absorption of clopidogrel by inducing the expression of Although considerable efforts have been put into the test, there are some limitations inherent in the study. First, the number of studies included are limited, especially for the information on the risk of MACE in patients treated with clopidogrel LD 300 mg and the outcome of bleeding. Thus the conclusion about these should be considered with caution. Second, detailed information such as the ethnicity and other main characteristic are not available in some studies, which further limit our evaluation. Third, gene-gene or gene-environment interaction, different loading or maintenance dose, influence from main clinical characteristics, standardized unbiased platelet activity evaluation and genotyping methods may affect the results. These variables can be planned more effectively by a separate analysis of these elements, to which we did not have access.ABCB1 3435T allele carrier was related to the risk of major adverse cardiovascular events in patients on clopidogrel LD 300 mg, and TT homozygotes decreased the outcome of bleeding compared with CC homozygotes, whereas, the association between ABCB1 C3435T polymorphism and platelet activity as well as other risks of poor clinical outcomes were not significant. Thus, to validate our findings, additional larger studies need to focus on homogeneous cases along with standardized platelet activity evaluation and genotyping methods in further tasks.In summary, our meta-analysis indicated that the Checklist S1PRISMA 2009 Checklist.(DOC)Click here for additional data file.


Positive results have a greater chance of being published and outcomes that are statistically significant have a greater chance of being fully reported. One consequence of research underreporting is that it may influence the sample of studies that is available for a meta-analysis. Smaller studies are often characterized by larger effects in published meta-analyses, which can be possibly explained by publication bias. We investigated the association between the statistical significance of the results and the probability of being included in recent meta-analyses.For meta-analyses of clinical trials, we defined the relative risk as the ratio of the probability of including statistically significant results favoring the treatment to the probability of including other results. For meta-analyses of other studies, we defined the relative risk as the ratio of the probability of including biologically plausible statistically significant results to the probability of including other results. We applied a Bayesian selection model for meta-analyses that included at least 30 studies and were published in four major general medical journals  between 2008 and 2012. We identified 49 meta-analyses. The estimate of the relative risk was greater than one in 42 meta-analyses, greater than two in 16 meta-analyses, greater than three in eight meta-analyses, and greater than five in four meta-analyses. In 10 out of 28 meta-analyses of clinical trials, there was strong evidence that statistically significant results favoring the treatment were more likely to be included. In 4 out of 19 meta-analyses of observational studies, there was strong evidence that plausible statistically significant outcomes had a higher probability of being included. Publication bias was present in a substantial proportion of large meta-analyses that were recently published in four major medical journals. When some study outcomes are more likely to be published than other, the literature that is available to doctors, scientists, and policy makers provides misleading information. The tendency to decide to publish a study based on its results has been long acknowledged as a major threat to the validity of conclusions from medical research,2. DurinMeta-analysis, a statistical approach to estimate a parameter of interest based on multiple studies, plays an essential role in medical research. One consequence of research underreporting is that it influences the sample of studies that is available for a meta-analysis,9. This It is well-known that smaller studies are often characterized by larger effects in published meta-analyses–16. PublFor meta-analyses of clinical trials, we a priori decided to estimate the ratio of the probability of including statistically significant results favoring the treatment to the probability of including other results. For other meta-analyses, we a priori decided to estimate the ratio of the probability of including plausible statistically significant results to the probability of including other results. The definition of plausibility was straightforward and a priori chosen. For meta-analyses of an association between a risk factor and an undesired outcome , results showing a positive association were regarded as plausible. For meta-analyses of an association between the absence of a risk factor and an undesired outcome, results showing a negative association were regarded as plausible. In meta-analyses of associations between alcohol consumption and cardiovascular parameters, we estimated the ratio of the probability of including statistically significant results to the probability of including not statistically significant results because both a positive and negative association is biologically plausible,25. A twWe used PubMed to identify meta-analyses published between 2008 and 2012 in four general medical journals . The term ‘meta-analysis’ was required to appear in the title or the abstract. Meta-analyses that combined at least 30 estimates from individual studies were considered. Only large meta-analyses were included because a substantial sample size is required to distinguish between the effects of heterogeneity and publication bias,26. We ci , given the true study effect αi and the within-study variance σi2, is assumed to be normal: f~N. The true study effect comes from a normal distribution: N, were µ is the mean effect size and τ2 is the between-study variance. When a selection process is present some studies may fail to enter the meta-analysis sample. To model the process of study selection, the probability that any specific study enters the sample is assumed to be multiplied by a nonnegative weight function. In this case, the observed study effects Xj that enter the meta-analysis sample  have a weighted density: fw=w(xj)f/∫w(x)fdx, where w(x) is a weight function. We applied a step weight function that took two values: ϒ1 for statistically significant results favoring the treatment  or plausible statistically significant results (in the case of other studies) and ϒ2 for other results, so that the RR equaled ϒ1/ϒ2For each identified meta-analysis, we applied a hierarchical selection model,27. In t1/ϒ2. We applied the algorithm described by Silliman, who considered a general class of hierarchical selection models[Maximum likelihood estimation is one possible approach to fit the model described above,28. We uon models. In our x= , σ= , α= , ϒ=, and s is the number of statistically significant results favoring the treatment  or plausible statistically significant results . A burn-in of 10000 iterations was sufficient to achieve convergence for all meta-analyses. The estimates were based on the subsequent 50000 iterations.whereFor point estimation, we used the median of the posterior distribution of RR. For interval estimation, we used the 95% equal-tail credible interval (CI). When the posterior probability that the RR exceeded 1 was greater than 0.95, we concluded that there was strong evidence that the RR was greater than 1. An R program that was used to fit the models can be found in In order to evaluate whether the statistical model was suitable for the objectives of the study, we performed simulations. The settings were based on the characteristics of the meta-analyses of clinical trials included in the study see . The posAdditionally, we compared the ability of our model to detect a selection process based on the statistical significance with publication bias methods widely used in medical research: the Egger’s test, correla2 prior for τ2  was declared for the number of degrees of freedom. A Winbugs program that was used to fit this model can be found in In order to investigate the robustness of the findings, two alternative models were considered. Because the conclusions drawn from a hierarchical model may be sensitive to the choice of the prior for the variance of the random effects, in the Out of 406 articles that were identified in the initial search, 88 articles did not report meta-analyses of an association. We excluded 280 articles because they did not describe a meta-analysis including at least 30 effect sizes. Further, 14 articles did not report any results from a meta-analysis of aggregate data. Finally, four articles were excluded because they did not report the effect sizes from the individual studies and the corresponding author did not respond to a request to provide them. Twenty reports including 49 meta-analyses were used in this study Click here for additional data file.Appendix S2Simulation details.(PDF)Click here for additional data file.Appendix S3Winbugs code for the model with t-distributed study-specific means.(PDF)Click here for additional data file.Appendix S4References of meta-analyses included in the study.(PDF)Click here for additional data file.Appendix S5Sensitivity analysis for meta-analyses of clinical trials.(PDF)Click here for additional data file.Appendix S6Sensitivity analysis for meta-analyses of observational and interventional studies.(PDF)Click here for additional data file.Appendix S7Raw data.(ZIP)Click here for additional data file.


Previous studies have focused on the association of miR-34 family members with carcinogenesis of many cancers, including hepatocellular carcinoma (HCC). It has been suggested that miR-34b/c polymorphism (rs4938723) is associated with susceptibility to HCC. In the present study, we performed a meta-analysis to systematically summarize the possible association between rs4938723 and the risk for HCC.We conducted a search of case-control studies on the associations of rs4938723 with susceptibility to HCC in PubMed, EMBASE, ISI Web of Science, Cochrane Central Register of Controlled Trials, ScienceDirect, Wiley Online Library, Wangfang database in China, and Chinese National Knowledge Infrastructure databases. Data from eligible studies were extracted for meta-analysis. HCC risk associated with rs4938723 was estimated by pooled odds ratios (ORs) and 95% confidence intervals (95% CIs). 3 studies on rs4938723 were included in our meta-analysis. Our results showed that neither allele frequency nor genotype distribution of the rs4938723 was associated with risk for HCC in all genetic models.This meta-analysis suggests that rs4938723 is not associated with the risk of HCC. Well-designed studies with larger sample size and more ethnic groups are required to further validate the results. Hepatocellular carcinoma (HCC) is the most common primary malignant cancer of the liver and the third leading cause of death from cancer worldwide. Epidemiological survey suggests that East and South-East Asia and Middle and Western Africa have the highest prevalence of HCC with almost half of the new cases and deaths in China We carried out a publication search in PubMed, EMBASE, ISI Web of Science, Cochrane Central Register of Controlled Trials, ScienceDirect, Wiley Online Library, Wangfang database in China, and Chinese National Knowledge Infrastructure (CNKI) databases with the following search terms: (miR-34b/c OR rs4938723) AND (hepatocellular carcinoma OR liver cancer OR hepatoma), by two independent investigators. Publication date and publication language were not restricted in our search. Reference lists were examined manually to further identify potentially relevant studies. All studies matching the inclusion criteria were retrieved for further examination and data extraction. All of the investigators have received training in literature search, statistics and evidence-based medicine.Studies included in this study must meet all the following criteria: (1) evaluated the associations between the rs4938723 and susceptibility to HCC, (2) studied on human beings, (3) in a case-control design, (4) detailed genotype data were provided for the calculation of odds ratio (OR) and 95% confidence interval (95% CI). We assessed the methodological qualities of included studies by the description of study population, detailed genotyping methods, the set of controls and cases and related statistical methods.For each study, the following characteristics were extracted: the first author's last name, year of publication, country of origin, ethnicity, the numbers of genotyped cases and controls, source of control groups, and genotyping methods.2 test to examin the heterogeneity between each study. By heterogeneity test, if P>0.05, we select the Fixed Effect Mode1, and if P<0.05, we select the Random Effect Mode1 to merge HR. P<0.05 was considered as significant difference. Analysis of sensitivity includes the difference of point estimation and confidence intervals of the combined effects value at a different model, to observe whether it changes the result. To test the publication bias, we used the RevMan 5.0 statistical software to make the funnel plot. The rs4938723 was tested for the associations with HCC susceptibility based on different genetic models. The meta-analysis examined the overall association of the rs4938723 with the risk of HCC measured by odds ratios (ORs) at the 95% confidence intervals (CIs). To contrast the wild-type homozygote (TT), we first estimated the risk of the rare allele homozygote (CC) and heterozygous (TC) genotypes on HCC, then evaluated the risk of HCC under a dominant model (CC+TC vs. TT) and a recessive model (TT+TC vs. CC). The statistical significance of the pooled OR was determined with the Z test, and a P value of <0.05 was considered significant.Meta-analysis was performed by using RevMan 5.0 software provided by the Cochrane Collaboration. We directly used Q-test and IA total of 123 articles were retrieved after first search in PubMed, EMBASE, ISI Web of Science, Cochrane Central Register of Controlled Trials, ScienceDirect, Wiley Online Library, Wangfang in China and CNKI databases. As shown in The association between miR-34b/c rs4938723 polymorphism and susceptibility to HCC was analyzed in four independent studies with 1, 672 cases and 1,749 controls. Funnel plot and Egger's test were performed to assess the publication bias of the literature. Symmetrical funnel plots were obtained in the SNP tested in all of the models. Egger's test further confirmed the absence of publication bias in this meta-analysis (P>0.05) .We deleted one single study from the overall pooled analysis each time to check the influence of the removed data set to the overall ORs. The pooled ORs and 95% CIs were not significantly altered when any part of the study was omitted, which indicated that any single study had little impact on the overall ORs.In the present meta-analysis, we did not find that rs4938723 in the promoter region of pri-miR-34b/c was associated with an increased risk of HCC. The SNP rs4938723 (T>C) located within the CpG island of pri-miR-34b/c and might create a predicted GATA-binding site, and therefore, it may affect miR-34b/c expression by both genetic and epigenetic mechanisms. Ectopic miR-34b/c caused cell cycle arrest in the G1 phase In this meta-analysis, a total of 3 case-control studies were analyzed to provide a comprehensive assessment of the association between miR-34b/c rs4938723 polymorphism and HCC. Genotypes in all studies were detected with genetic DNA from blood samples using 2 genotyping methods totally. All of the studies checked genotypes for quality control. Genotype distribution of controls in all studies was consistent with HWE. By the meta-analysis, our results did not support a genetic association between rs4938723 and susceptibility to HCC.2 = 0%). Sensitivity analysis also showed that omission of any single study did not have significant impact on the combined ORs. Furthermore, funnel plot did not reflect obvious asymmetry, and Egger's test further indicated no considerable publication bias in this meta-analysis. This made the results of this meta-study more reliable to some extent.Exploring heterogeneity is one of the important goals of meta-analysis Be that as it may, there remained some limitations in this meta-analysis. In the studies included, the genotyping methods used were not the same. Besides, other clinical factors such as age, sex and different chemotherapies in each study might lead to bias. Determining whether or not these factors influence the results of this meta-analysis would need further investigation.In conclusion, our study suggested that SNP rs4938723 in the promoter region of pri-miR-34b/c was associated with a significantly increased risk of HCC. Larger well-designed epidemiological studies with ethnically diverse populations and functional evaluations are warranted to confirm our findings.


Microsomal epoxide hydrolase (EPHX1) is an enzyme involved in the detoxification the products of smoking and is proposed to be a genetic factor for the development of chronic obstructive pulmonary disease (COPD). Two functional polymorphisms of EPHX1, T113C and A139G, have been analyzed in numerous studies to assess the COPD risk attributed to these variants. However, the conclusions were controversial. We performed a comprehensive meta-analysis to clarify these findings. A total of 24 studies comprising 8,259 COPD patients and 42,883 controls were included. The overall results showed that the EPHX1 113 mutant homozygote was significantly associated with an increased risk of COPD . The subgroup analyses demonstrated this association in Caucasian individuals  but not in Asian individuals. The 139 mutant heterozygote was significantly associated with a decreased risk of COPD in Asian populations  but not in Caucasian populations. Pooled analyses revealed that the extremely slow  and slow EPHX1 enzyme activity  were associated with an increased risk of COPD, while the fast enzyme activity was not associated with a decreased risk of COPD. The stratified analysis demonstrated this association in Caucasian but not in Asian individuals. Furthermore, a modest difference in the risk of COPD was observed between the subgroups by using the cigarette smokers or the non-smokers as controls. A significant correlation between the two functional polymorphisms, T113C and A139G, of the EPHX1 gene and the enzyme activity and the individual’s susceptibility to COPD was noted. In addition, the results supported a contribution of EPHX1 to the aetiology of COPD. Chronic obstructive pulmonary disease (COPD) is a complex disease characterized by irreversible airflow limitation, abnormal permanent distal air-space enlargement and emphysema in the lung. This is usually progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases . COPD isAs the only well-defined genetic factor of COPD, α1-antitrypsin deficiency, is rare in worldwide populations, other genetic factors must be involved in the susceptibility and development of COPD. Given that 95% of those who develop COPD are smokers, oxidative stress caused by smoking is considered to be a pathogenetic factor for COPD. Thus, the genes encoding enzymes that protect the lung against smoke-induced oxidative stress have received more attention and become the focus of genetic COPD studies. Microsomal epoxide hydrolase (EPHX1) is an enzyme essential for the metabolism of the highly reactive epoxide intermediates produced by cigarette smoke and is expressed at varying levels in the majority of tissues and cell types . EpidemiSince the initial report of an association between increased susceptibility to COPD and EPHX1 113 His-His homozygosity in Caucasian populations , a numbeIn the present study, a new comprehensive meta-analysis was performed to systematically investigate the association between the EPHX1 polymorphisms and an individual’s susceptibility to COPD. A total of 24 published case-control studies were included in this meta-analysis. The putative EPHX1 enzyme activity and risk of COPD were predicted by single polymorphism of T113C/A139G and combined double polymorphisms. Analyses stratified by ethnicity, sample size, cigarette smoking status of the controls and Hardy-Weinberg equilibrium (HWE) violation of the controls were performed to explore the variations which affect the final conclusion.A literature search was performed in PubMed, MEDLINE, Embase, Wanfang Database and Weipu Database for studies published up to April 2012 to use in the present meta-analysis. The key terms were ‘EPHX1 or microsomal epoxide hydrolase or EPHX or EPOX or HYL1 or MEH’, ‘COPD or chronic obstructive pulmonary disease’ and ‘polymorphism’ in various combinations. The search was limited to articles published in English and Chinese. References matching the above criteria were also searched manually to identify additional studies.The eligible investigations met the following criteria: i) the studies were case-control studies designed to explore the association between at least one of the two EPHX1 gene polymorphisms (T113C and A139G) and COPD susceptibility; ii) the studies provided data on the distribution of EPHX1 gene polymorphisms in the case-control population; iii) the studies were published in the English or Chinese language. Studies were excluded if they did not contain enough data for meta-analysis, were abstracts or reviews or were duplicated within other included studies.Two authors searched the studies and extracted the data according to the above inclusion and exclusion criteria. The following characteristics were collected from the eligible studies: first author, year of publication, country of studied population, ethnicity, sample size of the cohorts, number of COPD patients, number of controls, source of the control group  and the EPHX1 gene T113C and A139G allele and genotype distributions among the case and control groups. Different case-control groups within one study were considered to be independent studies. The cigarette smoking status of the controls was strategically classified as current smokers, ex-smokers and non-smokers.ORs with 95% CIs were calculated to assess the association between EPHX1 gene polymorphisms and COPD risk. The wild type homozygotes, TT of T113C and AA of A139G, were used as reference genotypes. Thus the comparisons were mutant homozygote or heterozygote vs. reference genotype . The ORs of COPD risk associated with EPHX1 enzymatic activity were estimated using the normal activity as the reference group . Stratified analyses were performed using ethnicity, sample size, cigarette smoking status of the controls and HWE violation of the controls.2 test (Q-test)   and P<0.n I2>75% . A highen I2>75% . The poon I2>75% ,38. The n I2>75% ,40. The Statistical analyses were performed using the Revman 5.1 software and STATA 10.0 software. The P-value was two-tailed and P<0.05 was considered to indicate a statistically significant difference.et al evaluated only the association between the EPHX1 113 T/C gene polymorphism and COPD risk , so a random-effect model was used for the analysis (After pooling the data from the 25 studies (with Smith and Harrison’s considered as two separate studies) for meta-analysis, the associations between the EPHX1 113 mutant homozygote and heterozygote and the COPD risk were analyzed. Summary ORs are shown in analysis .In the analysis stratified by ethnicity, the study populations were divided into two subgroups, one comprising Asian individuals (12 studies) and the comprising Caucasian individuals (12 studies). The pooled ORs showed a significant association between the 113 mutant homozygote and COPD risk in the Caucasian subgroup , but this was not significant in Asian subgroup . For sample size, the studies were stratified into two subgroups, one comprising studies with >200 subjects and one with <200 subjects. In these subgroups, a significant association between the 113 mutant homozygote and COPD risk was observed in the >200 subject subgroup , but not in the <200 subgroup . The pooled OR by the random-effects model showed no significant association between the 113 mutant homozygote and COPD risk . When these 15 studies were stratified by ethnicity, no statistically significant associations were detected .For case-control studies, a deviation from the HWE of the control groups may lead to an erroneous result and imply insufficient random sampling. Thus the 15 studies in which the controls were in HWE were analyzed. Six studies were in Asian populations, eight populations were Caucasian and one was African. There were significant heterogeneities among the populations . Overall, the OR was 1.12  and was not significant . Stratifying by ethnicity, sample size, smoking status of the controls and HWE violation of the controls also showed no association.A total of 24 studies detected an association between the 139 mutant homozygote and COPD risk. However, meta-analysis of these studies did not suggest an association between the 139 mutant homozygote and COPD risk  and there was no heterogeneity among the studies . Stratification by ethnicity demonstrated that there was no significant association in Caucasian populations  but revealed a statistically marginally significant association in Asian populations .A total of 24 studies detected the association between the 139 mutant heterozygote and COPD risk. The overall OR showed that the 139 mutant heterozygote was not significantly associated with COPD risk  and there was a low heterogeneity among the studies  and slow EPHX1 enzyme activity  increased the COPD risk significantly, while the fast EPHX1 enzyme activity did not affect the COPD risk , but not in the Asian populations . In the further assessments of the analyses stratified by sample size, smoking status of the controls and HWE violation of the controls, the extremely slow enzyme activity showed an increased COPD risk in the >200 subjects subgroup  and the subgroup with the non–smokers as controls . For the stratified analyses using the genetic model of slow enzyme activity vs. normal enzyme activity, the increased COPD risk was also observed in the >200 subjects subgroup . Notably, the increased COPD risk of the slow enzyme activity was observed not only in the subgroup with the non-smokers as controls  but also in the subgroup with the smokers and ex-smokers as controls  genetic model . NeitherThe EPHX1 gene encodes a xenobiotic metabolizing enzyme that detoxifies the reactive epoxides produced by smoking to form water and soluble dihydrodiol compounds and is widely expressed in the bronchial epithelium. Thus it has been a significant focus for studies concerning genetic susceptibility to COPD over the past decade. The genetic polymorphisms T113C and A139G in the coding regions have been observed to alter the enzyme activity and thus, are considered to affect the individual’s susceptibility to COPD or risk of developing COPD. However, studies of genetic polymorphisms of EPHX1 in COPD have provided different and inconclusive results.The explanations for this may be the different ethnic populations used in the various studies, relatively small sample sizes lacking the statistical power to produce a reliable conclusion for any individual study or mismatching for age, gender and smoking history in the controls. A perfect COPD genetic association study would be large and longitudinal, using the cumulative reduction in lung function in relation to cumulative smoking as a main outcome measure. Such a study would take decades to complete and require tens of thousands of subjects. Thus, to avoid these error sources, meta-analysis studies appear to be an essential tool for summarizing case-control studies.et al, in which a reduced risk of COPD was detected in the 113 mutant homozygotes (et al, in which an increased risk of COPD was observed in Asian populations, not in Caucasian populations (et al, in which the 113 mutant homozygote was not associated with CODP either in Asian or Caucasian populations (et al, the authors also noted that when the COPD patients were non-smokers, the low activity genotype was a risk factor, but became a protective factor when the COPD patients were smokers (The present meta-analysis provides the most comprehensive and up-to-date evidence on the EPHX1 genetic polymorphisms T113C and A139G, enzyme activity resulting from these two genetic polymorphisms and the risk of developing COPD. A total of 25 case-control association studies with 8,259 COPD patients and 42,883 controls were included in the present meta-analysis. Through systematic analyses, the 113 mutant homozygote was demonstrated to be significantly associated with an increased risk of COPD. This result contrasted with the study by Brøgger ozygotes . The anaulations . The resulations . The reaulations . In the  smokers . Thus inWhen evaluating the EPHX1 enzyme activity and the risk of COPD, the extremely slow activity phenotype and slow activity phenotype of EPHX1 were revealed to be significantly associated with an increased risk of COPD. The stratified analyses demonstrated the association in Caucasian populations, studies with >200 subjects and studies with non-smokers as the controls. These findings are consistent with the known role of the EPHX1 enzyme in the detoxification of harmful epoxides from smoking and its involvement in the first-pass metabolism of smoking-induced highly reactive epoxide intermediates . RegardlAlthough meta-analysis is a powerful statistical method, the inherent limitations of the present study should be addressed. Thus, in interpreting the results, caution should be taken. First, relatively large heterogeneity existed in the 113 mutant homozygote vs. wildtype homozygote meta-analysis. Analyses stratified by ethnicity, sample size, cigarette smoking status of the controls and HWE violation of the controls did not significantly reduce the heterogeneity. The heterogeneity may be caused by the different criteria in the selection of COPD patients and controls, including age and gender distributions and lifestyle factors. However, the lack of original data for the included studies limited any further evaluation. Second, only studies written in English and Chinese were included and related studies in other languages were not included, which may bias the conclusion of the present study. Third, publication bias may not be excluded, although the tests showed negative results. Studies reporting significant associations would be more readily published, while studies with non-significant associations would be more difficult to publish. Fourth, although half of the included studies were performed in Asian populations, the total size of the Asian populations was relatively small compared with the Caucasian populations. In the analyses stratified by ethnicity, the detected associations were only demonstrated in the Caucasian populations, not in the Asian populations. As the scale of the effect of EPHX1 variants on the risk of COPD may depend on ethnicity , more stIn conclusion, the present meta-analysis is the most comprehensive and up-to-date appraisal of the two EPHX1 genetic polymorphisms, T113C and A139G, enzyme activity and the risk of developing COPD. The results indicated that they were genetic factors for the susceptibility of an individual to COPD. Further well-designed studies of various ethnic populations should be performed to evaluate these associations.


PTPN22) is a key negative regulator of T lymphocytes and polymorphisms of the PTPN22 gene have been shown to be associated with various immune-related diseases. The present study was performed to assess the association between PTPN22 polymorphisms and Behcet's disease in two Chinese Han populations.Behcet's disease is known as a recurrent, multisystem inflammation and immune-related disease. Protein tyrosine phosphatase non-receptor 22  and ocular Behcet's disease (p>0.05). Categorization analysis according to the clinical features did not show any association of these three polymorphisms with these parameters (p>0.05).A total of 516 patients with ocular Behcet's disease and 690 healthy controls from two Chinese Han populations were genotyped by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method for three single nucleotide polymorphisms (SNPs). Hardy-Weinberg equilibrium was tested using the χPTPN22 gene polymorphisms  were not associated with ocular Behcet's disease in two Chinese Han populations, and showed that it may be different from other classical autoimmune diseases. More studies are needed to confirm these findings for Behcet's disease in other ethnic backgrounds.The investigated  HLA)-B51 is thought to be the most strongly associated genetic factor predisposing to BD. The contribution of HLA-B51 to the genetic risk of BD has however been estimated to be less than 20%. Therefore study on non-HLA genes, especially related to the immune response and inflammation is of great importance. Several immune relevant genes, such as the IL-23 receptor gene, IL-10 gene and SUMO4 gene, have been revealed to be risk factors for BD Behcet's disease (BD) is known as a multisystem inflammatory disorder of unknown etiology. It is characterized by recurrent attacks of uveitis, oral ulceration, genital ulceration, skin lesions, arthritis, and vascular inflammation PTPN22) gene maps to chromosome 1p13.3-p13.1, and encodes the lymphoid-specific phosphatase known as Lyp, which contains a catalytic N-terminal domain and a non-catalytic C-terminus composed of four proline-rich domains. Lyp is an important down-regulator of T-cell activation through interacting with protein tyrosine kinase (Csk) and inhibiting signaling pathways mediated by the T-cell receptor (TCR) PTPN22 could trigger the immune and inflammation response by decreasing the affinity between Lyp and Csk, thereby inhibiting the TCR signaling pathway PTPN22 has been shown to be associated with susceptibility to a number of immune related-diseases, such as type 1 diabetes (T1D), rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) The protein tyrosine phosphatase non-receptor 22 (PTPN22 gene and concluded that this polymorphism had a limited (protective) role in disease pathogenesis PTPN22 gene with BD, and this was therefore the purpose of the study presented here. The frequencies of some alleles display great variation in different regions and ethnic groups worldwide. The International HapMap data and recent reports showed the SNP rs2476601 (1858C/T) are not polymorphic in Chinese Han populations, although they have been shown to be associated with susceptibility for immune diseases in other ethnic groups PTPN22 gene polymorphisms with risk to ocular BD.Earlier studies in a Turkish population with BD analyzed the rs2476601 genotype of the p>0.05). There were also no significant differences in the distribution of gender for the case-control study in groups (p>0.05). The age and gender distribution of the ocular BD patients and healthy controls are shown in No statistical differences were observed in the distribution of age for the Chinese Han case-control cohorts . The RFLP genotyping matched results obtained by direct sequencing. The genotype and allele frequencies of the three SNPs of PTPN22 examined in BD patients and healthy controls are summarized in p>0.05), and similar results were observed when comparing the combined patient cohorts with the controls (p>0.05). Under the null hypothesis , OR (odd ratio) is expected to be 1.000.A total of 516 ocular BD patients and 690 healthy controls were genotyped for three SNPs of PTPN22 SNPs were associated with the various clinical features of ocular BD, such as oral ulceration, genital ulceration, hypopyon, skin lesions, positive pathergy test and arthritis. The analysis did not indicate any significant association of these parameters with the tested three SNPs of PTPN22 (p>0.05) (data not shown).In addition, we investigated whether the Numerous factors have been reported to influence the results of the study on the association of gene polymorphisms with disease. We made the following efforts to ensure correctness of the results. The ocular BD patients were selected strictly according to the criteria of the International Study Group or the revised criteria from Behcet's Disease Research Committee of Japan if oral ulceration was not present, and two cohorts of the samples came from two independent uveitis centers in China. The healthy individual controls were recruited from the same geographical regions as the patients. No statistical differences were observed in the distribution of age and gender for the collected Chinese Han case-control cohorts. In order to validate the results of genotyping by PCR-restriction fragment length polymorphism, 10% of the samples were randomly chosen and confirmed by direct sequencing.PTPN22 gene has emerged as an important candidate susceptibility factor for a number of immune diseases PTPN22 in clinical uveitis had been addressed in British, Turkish and Middle-East BD patients and described a limited (protective) effect of the T1858 allele in the Middle East patients but not in the UK group et al showed no association between the R620W (rs2476601) of PTPN22, 1858C/T genotype and acute anterior uveitis et al revealed that the above polymorphism of PTPN22 gene had no influence on Crohn's disease (CD) in Germans et al also failed to demonstrate any correlation of the above SNP with Multiple sclerosis (MS) in Spanish patients PTPN22 polymorphisms has consistently been reported as a susceptibility gene for a number of autoimmune diseases characterized by specific autoantibodies PTPN22 has always been presumed to be a genetic switch for autoimmunity, the lack of an association with the common SNPs of this gene may provide additional evidence to the hypothesis that BD is autoinflammatory rather than an autoimmune disease.During recent years the PTPN22 gene is not strong enough. The patients were only recruited from the Chinese Han population. Therefore, the association of PTPN22 polymorphisms with BD should be studied using a larger sample size and other ethnic populations. On the other hand, BD is a complex disease that affects multiple systems, and the tested patients from an ophthalmology department represent a subpopulation of this disease. The association of PTPN22 polymorphisms with BD should therefore also be investigated in BD patients from other medical departments, such as dermatology and stomatology. Finally, the present study only examined three of the PTPN22 polymorphisms, therefore it does not exclude the possibility that other SNPs of PTPN22 are associated with BD. More studies are needed to clarify these issues.Like other candidate gene research, there are some limitations in our study. The size of patient samples seems to be relatively small if the pathogenic role of the PTPN22 gene  and susceptibility for ocular BD in Chinese Han patients.In conclusion, our study failed to find any association between the three polymorphisms of Two independent Chinese Han population case-control cohorts were included in this study. Cohort 1 consisted of 251 ocular BD cases and 336 controls collected at the Zhongshan Ophthalmic Center  from January 2005 to March 2008. Cohort 2 consisted of 265 ocular BD cases and 354 controls collected at the First Affiliated Hospital of Chongqing Medical University  from March January 2008 to May 2011. All patients had intraocular inflammation. In total, there were 516 patients with ocular BD and 690 healthy controls, whereby the comparison was performed as a case-control study in groups. Controls were not matched to case, individually or in larger groups. The proportion of male vs female is 5∶1 to 4∶1 both in the cases and controls. The diagnosis of BD was made according to the criteria of the International Study Group for BD or the revised criteria from Behcet's Disease Research Committee of Japan if oral ulceration was not present The protocol was approved by the Ethics Committee of the First Affiliated Hospital of Chongqing Medical University, Chongqing, China (Permit Number: 2009-201004), and written informed consent was obtained from all the study subjects. All procedures followed the tenets of the Declaration of Helsinki.Blood samples were collected in EDTA tubes and kept at −70°C until used. Genomic DNA was extracted by the QIAamp DNA Blood Mini Kit . Amplification of the target DNA in the PTPN22 gene was analyzed by the polymerase chain reaction (PCR) using primers presented in 2 test. The variable age, described as mean ± standard deviation (SD), median and range, between cases and controls was compared using the student's t-test. The variable gender was compared with Chi-square tests between cases and controls. Genotype frequencies were estimated by direct counting. Allele and genotype frequencies were compared between patients and controls by the unconditional logistic regression analysis , which was used to compute the odds ratios (ORs) and their 95% confidence intervals (CIs). This statistical method was also performed to analyze the association between the SNPs and various clinical features of ocular BD. All statistical tests were two-sided. P<0.05 was considered significant.Hardy-Weinberg equilibrium was tested using the χ