Homozygote Comparison Research Articles

Interleukin-23R rs7517847 T/G Polymorphism Contributes to the Risk of Crohn's Disease in Caucasians: A Meta-Analysis.

The association between Interleukin-23R gene polymorphism and Crohn's disease (CD) in Caucasians is still controversial. Thus, a meta-analysis was performed to evaluate the correlation between this gene variant and CD risk. We retrieved the available data from EMBASE and PUBMED until May 1, 2014, and evaluated the effect of rs7517847 in Caucasians. The significant associations were confirmed between rs7517847 and CD risk in dominant models (TT/TG versus GG: OR = 1.652, 95% CI 1.277, 2.137), allelic model (T allele versus G allele: OR = 1.327, 95% CI 1.198, 1.469), homozygote comparison (TT versus GG: OR = 1.890, 95% CI 1.465, 2.437), heterozygote comparison (TG versus GG: OR = 1.509, 95% CI 1.161, 1.960), and recessive model (TT versus TG/GG: OR = 1.409, 95% CI 1.279, 1.552). In conclusion, this meta-analysis demonstrates that rs7517847 is associated with the risk of CD in Caucasians. These findings show that IL-23R genes confer susceptibility to CD in the Caucasians.

Systematic meta-analysis of the association between monocyte chemoattractant protein-1 -2518A/G polymorphism and risk of tuberculosis.

Numerous studies have been conducted to investigate the association between 2518A/G polymorphisms in the monocyte chemoattractant protein-1 (MCP-1) gene and the risk of tuberculosis (TB). However, the results have been inconsistent and inconclusive. In this study, we performed a meta-analysis to evaluate the association between the MCP-1 -2518A/G polymorphism and TB. The National Center for Biotechnology Information Global Cross Database and Google Scholar database were searched for relative studies. A total of 22 case-control studies that included 7332 cases and 8004 controls for the -2518A/G single-nucleotide polymorphism were identified. The results revealed an association between the MCP-1 -2518A/G polymorphism and human TB susceptibility under a recessive model (GG vs GA+AA), dominant model (GG+GA vs AA), and homozygote comparison (GG vs AA) model for the entire database. For the dominant model, the overall odds ratio was 1.34 (95% confidence interval, 1.10-1.64, P = 0.004). For the recessive model, the overall odds ratio was 1.46 (95% confidence interval, 1.15- 1.86, P = 0.002). For the homozygote comparison, the overall odds ratio was 1.67 (95% confidence interval, 1.20-2.32, P = 0.002). In the subgroup analysis by ethnicity, significantly elevated risks were found in Asians and Americans, but not in Africans and Europeans. We also used the Begg and Egger tests to examine publication bias, and no major publication bias was detected. Our results indicate that there is an association between the MCP-1 -2518A/G polymorphism and human TB susceptibility.

Association between XRCC1 Arg280His polymorphism and risk of hepatocellular carcinoma: a systematic review and meta-analysis.

Hepatocellular carcinoma (HCC) is one of the most life-threatening malignancies worldwide. Defects in DNA repair genes may increase the risk of HCC. X-ray cross-complementing group 1 gene (XRCC1) is a major DNA repair gene involved in base excision re-pair. Recently, several studies have indicated that an association exists between XRCC1 polymorphism and HCC, particularly the Arg280His polymorphism. However, the data is inconsistent and incomplete. In this study, we conducted a meta-analysis to investigate the association between the XRCC1 Arg280His polymorphism and HCC risk. A total of 10 case-control studies included 1848 HCC cases and 1969 controls were examined in this analysis. Our results suggest that variant geno-types of the XRCC1 Arg280His gene are associated with a significantly increased risk of HCC in homozygote comparison (HisHis vs ArgArg, odds ratio, 1.55, 95% confidence interval, 1.10-2.18, P = 0.013); no het-erogeneity was observed (I2 = 0%). Our analysis suggests that the XRCC1 Arg280His polymorphism is associated with a higher risk of HCC.

The Protective Effect of Transcription Factor 7-Like 2 Risk Allele rs7903146 against Elevated Fasting Plasma Triglyceride in Type 2 Diabetes: A Meta-Analysis.

Background. The results from published studies regarding association of transcription factor 7-like 2 (TCF7L2) variant rs7903146 with dyslipidemia have been conflicting and inconclusive. Methods. We carried out a meta-analysis that aimed to investigate the association of the rs7903146 variant with plasma lipid levels using electronic database and published studies. Data was extracted by a standard algorithm. Dominant, recessive, homozygote, and heterozygote comparison models were utilized. Results. 24 studies incorporating 52,785 subjects were included in this meta-analysis. Overall, the minor allele (T) was associated with lower risk for hypertriglyceridemia in subjects with type 2 diabetes (dominant model: SMD = −0.04, 95% CI (−0.08, 0.00), P = 0.048, P heterogeneity = 0.47; recessive model: SMD = −0.10, 95% CI (−0.18, −0.02), P = 0.01, P heterogeneity = 0.56). No association was found between minor (T) allele and plasma TC, LDL-c, or HDL-c levels in subjects with type 2 diabetes or metabolic syndrome (MetS) and no association was found between minor (T) allele and plasma TG levels in nondiabetic subjects. Conclusions. Our meta-analysis indicated the association between TCF7L2 rs7903146 polymorphism and low plasma triglyceride (TG) level in subjects with type 2 diabetes. No association was found between rs7903146 variant and plasma lipids in nondiabetic subjects.

Association Between ESR1 PvuII, XbaI, and P325P Polymorphisms and Breast Cancer Susceptibility: A Meta-Analysis.

BackgroundBreast cancer is one of the leading causes of cancer-related deaths for women. Numerous studies have shown that single-nucleotide polymorphisms (SNPs) on the ESR1 gene are associated to this disease. However, data and conclusions are inconsistent and controversial.Material/MethodsTo investigate the association between PvuII (rs2234693), XbaI (rs9340799) and P325P (rs1801132) polymorphisms of ESR1 gene with the risk of breast cancer under different population categorizations, we searched multiple databases for data collection, and performed the meta-analysis on a total of 25 case-control studies. Three different comparison models – dominant model, recessive model, and homozygote comparison model – were applied to evaluate the association.ResultsOur results indicated that people with TT+TC or TT genotype were at a greater risk of developing breast cancer than those with CC genotype in the PvuII polymorphism. While for XbaI and P325P polymorphisms, no significance was found using any of the 3 models. Furthermore, the data were also stratified into different subgroups according to the ethnicity (white or Asian) and source of controls (hospital-based or population-based), and separate analyses were conducted to assess the association. The ethnicity subgroup assessment showed that the higher risk of breast cancer for TT genotype of PvuII polymorphism than CC genotype only occurred in Asian people, but not in white populations. For the source-stratified subgroup analysis, significant association suggested that people with TT + TC genotype were at a greater risk of developing breast cancer than those with CC genotype in the hospital-based subgroup.ConclusionsThus, this meta-analysis clarified the inconsistent conclusions from previous studies, conducted analyses for the entire population as well as for different subgroups using diverse population categorization strategies, and has the potential to help provide a personalized risk estimate for breast cancer susceptibility.

The association of MDM2 c.346G>A genetic variant with the risk of osteosarcoma in Chinese.

OR=2.32, 95% CI 1.30-4.13, χ2=8.50, p=0.004), and allele comparison (A vs. G: OR=1.27, 95% CI 1.01-1.60, χ2=4.34, p=0.037). Results from this study indicated that the allele-A and genotype-AA of MDM2 c.346G>A genetic variant could be an increased risk factor for the susceptibility to osteosarcoma and might be used as a potential molecular marker for evaluating the risk of osteosarcoma.

Polymorphism of DNA methyltransferase 3B -149C/T and cancer risk: a meta-analysis.

Published data on the association between DNA methyltransferase (DNMT) 3B −149C/T polymorphism and cancer risk remain inconclusive. To derive a more precise estimation for this association, we performed a meta-analysis of 5,903 cancer cases and 8,132 controls from 22 published case–control studies. We used odds ratios (ORs) with 95 % confidence intervals (CIs) to assess the strength of the association. Our meta-analysis suggested that DNMT3B −149C/T polymorphism was associated with the risk of head and neck cancer under heterozygote comparison (OR 0.73, 95 % CI 0.59–0.90) and dominant model (OR 1.75, 95 % CI 0.62–0.92), although no evidence of association between DNMT3B −149C/T polymorphism and cancer risk was observed as we compared in the pooled analyses (homozygote comparison: OR 0.96, 95 % CI 0.86–1.09; heterozygote comparison: OR 1.07, 95 % CI 0.86–0.32; dominant model: OR 1.03, 95 % CI 0.85–1.25; recessive model: OR 0.93, 95 % CI 0.8–1.08). More studies are needed to detect DNMT3B −149C/T polymorphism and its association with cancer in different ethnic populations incorporated with environment exposures in the susceptibility of different kinds of cancer.

Role of Bcl-2 -938 C>A polymorphism in susceptibility and prognosis of cancer: a meta-analysis.

The association between B-cell lymphoma 2 (Bcl-2) polymorphism and cancer is under debate and remains elusive. This meta-analysis was performed to evaluate the relationships of Bcl-2 -938 C>A polymorphism (rs2279115) with susceptibility and prognosis of cancer. Odds ratios (ORs) were used to measure the association between Bcl-2 polymorphisms and cancer risk. Hazard ratios (HRs) were used to measure the association between Bcl-2 polymorphisms and cancer prognosis. On the basis of 26 studies about Bcl-2 -938C>A polymorphism and cancer, we found Bcl-2 -938 C>A polymorphism was significantly associated with increased cancer risk in dominant model (OR = 1.12, 95%CI: 1.00–1.25, P = 0.04), recessive model (OR = 1.38, 95%CI: 1.11–1.71, P = 0.004), allelic model (OR = 1.15, 95%CI: 1.04–1.28, P = 0.007) and homozygote comparison(OR = 1.44, 95%CI: 1.11–1.87, P = 0.006). Furthermore, Bcl-2 -938 C>A polymorphism was significantly associated with increased cancer risk in Asians but not in Caucasians. Moreover, Bcl-2 -938 C>A polymorphism was not significantly associated with the prognosis of cancer (AA vs CA: OR = 0.99, 95%CI: 0.77–1.27, P = 0.93; AA vs CC: OR = 0.92, 95%CI: 0.65–1.30, P = 0.63; AC vs CC: OR = 0.94, 95%CI: 0.80–1.11, P = 0.48; CC vs AA+CA: OR = 1.21, 95%CI: 0.69–2.13, P = 0.50; AA vs CC+CA: OR = 0.99, 95%CI: 0.48–2.04, P = 0.97). Studies with larger samples and gene-environment interactions are needed to validate our findings.

The association between the SNP rs763110 and the risk of gynecological cancer: A meta-analysis

FAS and FAS ligand (FASL) are the principal genes of the apoptosis pathway, which play a vital role in the etiology of various gynecological cancers. Studies have revealed that polymorphism of FASL promoter -844C>T (rs763110) influences FASL transcription process, which involving in cancer risk. Moreover, estrogen has been proved to trigger T-cell apoptosis by up-regulating FAS/FASL system in cancer cells. However, results from the published studies on the association between FASL -844C>T polymorphism and risk of gynecological cancer are conflicting. We performed a meta-analysis based on 13 case-control studies, including a total of 6256 cancer cases and 5573 controls. We used odd ratios (ORs) with 95% confidence intervals (CIs) to assess the association strength. Overall, the FASL -844CT and TT genotypes were associated with a significantly reduced risk of gynecological cancer types in homozygote comparison (OR=0.80, 95% CI=0.64–0.99), heterozygote comparison (OR=0.81, 95% CI=0.67–0.98), and dominant model (OR=0.81, 95% CI=0.67–0.98). In the stratified analyses, we observed a similar association among Asian population (heterozygote comparison: OR=0.73, 95% CI=0.56–0.95; dominant model: OR=0.75, 95% CI=0.57–0.98) and hospital-based studies (homozygote comparison: OR=0.61, 95% CI=0.43–0.86). When stratified by cancer type, there was also a significantly lower risk of the ovarian cancer in different genetic models except the recessive one. The results suggested that the FASL -844C>T polymorphism may reduce the risk of gynecological cancer.

Association of TLR4 gene polymorphisms with susceptibility to type 2 diabetes mellitus in the Chinese Han population.

Toll-like receptor 4 (TLR4) gene plays important roles in the susceptibility to type 2 diabetes mellitus (T2DM). This study aims to detect the potential association of TLR4 gene polymorphisms with the susceptibility to T2DM in the Chinese Han population. 685 T2DM patients and 690 healthy controls were enrolled in this case-control study. The genotypes of TLR4 gene polymorphisms were analyzed by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing methods. We detected the g.13726T>C and g.15090G>A genetic polymorphisms. Our data supported that the g.13726T>C and g.15090G>A genetic polymorphisms were significantly associated with the increased susceptibility to T2DM in the homozygote comparison, recessive model, and allele contrast (all P-values<0.01). The allele-C and genotype-CC of g.13726T>C and allele-A and genotype-AA of g.15090G>A genetic polymorphisms might be the risk factors for increasing the susceptibility to T2DM. These preliminary findings indicate that the g.13726T>C and g.15090G>A genetic polymorphisms of TLR4 gene are potentially related to the susceptibility to T2DM in the studied population, and might be used as molecular markers for evaluating the risk of T2DM.

Angiotensin-converting enzyme insertion/deletion polymorphism is not a major determining factor in the development of sporadic Alzheimer disease: evidence from an updated meta-analysis.

Angiotensin-converting enzyme gene (ACE) insertion/deletion (I/D) polymorphism have long been linked to sporadic Alzheimer disease (SAD), but the established data remained controversial. To clarify this inconsistency, a comprehensive meta-analysis was conducted. Through searching of Pubmed, Embase, Alzgene, China National Knowledge Infrastructure (CNKI) and manually searching relevant references, 53 independent studies from 48 articles were included, involving a total of 8153 cases and 14932 controls. The strength of association was assessed by using odds ratios (ORs) with 95% confidence intervals (CIs). Further stratified analyses and heterogeneity analyses were tested, as was publication bias. Overall, significant associations were revealed between I/D polymorphism and SAD risk using allelic comparison (OR = 1.09, 95%CI = 1.01–1.17, p = 0.030), homozygote comparison (OR = 1.17, 95%CI = 1.01–1.34, p = 0.030) and the dominant model (OR = 1.16, 95%CI = 1.04–1.29, p = 0.008), but they were not sufficiently robust to withstand the false-positive report probability (FPRP) analyses. Otherwise, in subgroup analyses restricted to the high quality studies, the large sample size studies and studies with population-based controls, no significant association was observed in any genetic models. In summary, the current meta-analysis suggested that the ACE I/D polymorphism is unlikely to be a major determining factor in the development of SAD.

Association between genetic polymorphisms in AURKA (rs2273535 and rs1047972) and breast cancer risk: a meta-analysis involving 37,221 subjects.

BackgroundPublished data on the association between AURKA polymorphisms and breast cancer (BC) risk are inconclusive. This meta-analysis was performed to derive a more precise estimation on the relationship between AURKA polymorphisms (rs2273535 and rs1047972) and BC risk.MethodsPubMed, Web of Knowledge and Embase were searched for relevant studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the strength of associations. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were performed for allele contrast genetic model, homozygous genetic model, heterozygote genetic model, dominant model, and recessive model, respectively.ResultsA total of 13 studies (16,349 BC patients and 20,872 case-free controls) were involved in this meta-analysis. Meta-analysis showed that there was significant association between rs2273535 and BC risk in three genetic models in the overall population (A vs. T: OR = 1.08, 95% CI = 1.01–1.15, P = 0.02; AA vs. TT: OR = 1.36, 95% CI = 1.06-1.73, P < 0.00001; AA vs. TT + TA: OR = 1.15, 95% CI = 1.01-1.31, P = 0.04). In the subgroup analysis by ethnicity, the effects remained in Asians (allele contrast genetic model: OR = 1.12, 95% CI = 1.00-1.26, P = 0.04 and homozygote comparison: OR = 1.22, 95% CI = 1.06-1.41, P = 0.007). However, no genetic models reached statistical association in Cauasians. Rs1047972 polymorphism was associated with BC risk in the overall population based on homozygote comparison (AA vs. GG: OR = 0.81, 95% CI = 0.66-0.99, P = 0.04). When stratified by ethnicity, rs1047972 polymorphism had a decreased association with BC risk in Caucasians based on allele contrast genetic model, homozygote comparison, the dominant model and the recessive model. However, there was no association in any genetic model in Asians.ConclusionsThis meta-analysis suggests that AURKA rs2273535 polymorphism has an increased risk with BC, especially in Asians. However, rs1047972 polymorphism has a decreased BC risk in Caucasians. Further large scale multicenter epidemiological studies are warranted to confirm this finding.

Association of Rs11615 (C>T) in the excision repair cross-complementing group 1 gene with ovarian but not gynecological cancer susceptibility: a meta-analysis.

Evidence suggests that the rs11615 (C>T) polymorphism in the ERCC1 gene may be a risk factor for gynecological tumors. However, results have not been consistent. Therefore we performed this meta- analysis. Eligible studies were identified by search of PubMed, MEDLINE and Chinese National Knowledge Infrastructure (CNKI). Odds ratios (ORs) and 95% confidence intervals (CIs) were applied to assess associations between rs11615 (C>T) and gynecological tumor risk. Heterogeneity among studies was tested and sensitivity analysis was applied. A total of 6 studies were identified, with 1,766 cases and 2,073 controls. No significant association was found overall between the rs11615 (C>T) polymorphism and gynecological tumor susceptibility in any genetic model. In further analysis stratified by cancer type, significantly elevated ovarian cancer risk was observed in the homozygote and recessive model comparison (TT vs CC: OR=1.69, 95% CI=1.03-2.77, heterogeneity=0.876; TT vs OR=1.72, 95% CI=1.07-2.77, heterogeneity=0.995). The results of the present meta-analysis suggest that there is no significant association between the rs11615 (C>T) polymorphism and gynecological tumor risk, but it had a increased risk in ovarian cancer.

The methylenetetrahydrofolate reductase C677T polymorphism and breast cancer risk in Asian populations.

Methylenetetrahydrofolate (MTHFR) is the key enzyme of the folate metabolic pathway and several studies have pointed to association between the MTHFR C677T polymorphism and breast cancer risk. Although significant association was observed in some studies, in others no clear link could be established. A meta-analysis of published Asian case control studies was therefor carried out to shed further light on any C677T breast cancer association. PubMed, Springer Link, Google Scholar and Elsevier databases were searched for case control studies of associations between MTHFR C677T polymorphism and breast cancer risk. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. A total of 36 studies including 8,040 cases and 10,008 controls were included in the present meta-analysis. Overall, a significantly elevated breast cancer risk was associated with the T allele and TT genotype in homozygote comparison and dominant genetic models when all studies were pooled into the meta-analysis (T vs C (allele contrast model): OR=1,23, 95%CI=1.13-1.37, p=0.000 ; TT vs CC(homozygote model): OR=1.38, 95%CI=1.16-1.63, p=0.0003; TT+CT vs CC (dominant model): OR=1.12, 95%CI=1.01-1.23, p=0.02). The present meta-analysis strongly suggested a significant association between the MTHFR C677T polymorphism and risk of breast cancer in Asian populations.

Association Between Methionine Synthase Reductase A66G Polymorphism and the Risk of Congenital Heart Defects: Evidence From Eight Case–Control Studies

Methionine synthase reductase (MTRR) plays a major role in hyperhomocysteinemia, a risk factor related to the occurrence of congenital heart defects (CHDs). However, the associations between MTRR polymorphism and CHDs have been inconclusive. Thus, a metaanalysis of eight case-control studies was conducted to investigate 3,592 cases and 3,638 control subjects for MTRR A66G polymorphism to identify the association. Odds ratios (ORs) and 95 % confidence intervals (95 % CIs) were used to assess the strength of the association. The results showed that MTRR A66G polymorphism was associated with a higher CHD risk in the allele comparison (G vs A: OR 1.163; 95 % CI 1.016-1.330; P heterogeneity = 0.004), the homozygote comparison (GG vs AA: OR 1.332; 95 % CI 1.020-1.740; P heterogeneity = 0.035), and the dominant model (GG/AG vs AA: OR 1.218; 95 % CI 1.001-1.482; P heterogeneity = 0.001). In the subgroup analysis, this polymorphism was associated with CHDs in Asians in the homozygote comparison (GG vs AA: OR 1.427; 95 % CI 1.017-2.001; P heterogeneity = 0.019) and the allele comparison (G vs A: OR 1.203; 95 % CI 1.018-1.422; P heterogeneity = 0.002). In summary, the metaanalysis demonstrated that MTRR A66G polymorphism is a risk factor for CHDs. Further studies should be performed to investigate the association of plasma homocysteine levels, enzyme activity, parental genotypes, and vitamin complex intakes with the risk of CHDs.

Association of interferon regulatory factor 4 gene polymorphisms rs12203592 and rs872071 with skin cancer and haematological malignancies susceptibility: a meta-analysis of 19 case-control studies.

BackgroundResearch has indicated that the rs12203592 and rs872071 interferon regulatory factor 4 (IRF4) gene polymorphisms correlate with the risk of cancer, especially skin cancer and haematological malignancies, but the results remain controversial. To understand better the effects of these two polymorphisms on skin cancer and haematological malignancies susceptibility, a cumulative meta-analysis was performed.MethodsWe conducted a search using the PubMed and Web of Science databases for relevant case-control studies published before April 2014. Summary odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using fixed- or random-effects models where appropriate. Heterogeneity test, publication bias test, and sensitivity analysis were also performed.ResultsIn total, 11 articles comprised of 19 case–control studies were identified; five focused on the rs12203592 polymorphism with 7,992 cases and 8,849 controls, and six were on the rs872071 polymorphism with 3108 cases and 8300 controls. As for rs12203592, a significant correlation with overall skin cancer and haematological malignancies risk was found with the homozygote comparison model (OR = 1.566, 95% CI 1.087-2.256) and recessive model (OR = 1.526, 95% CI 1.107-2.104). For rs872071, a significantly elevated haematological malignancies risk was observed in all genetic models (homozygote comparison: OR = 1.805, 95% CI 1.402-2.323; heterozygote comparison: OR = 1.427, 95% CI 1.203-1.692; dominant: OR = 1.556, 95% CI 1.281-1.891; recessive: OR = 1.432, 95% CI 1.293-1.587; additive: OR = 1.349, 95% CI 1.201-1.515). Similarly, increased skin cancer and haematological malignancies risk was also identified after stratification of the SNP data by cancer type, ethnicity and source of controls for both polymorphisms.ConclusionsOur meta-analysis indicated that the rs12203592 and rs872071 IRF4 gene polymorphisms are associated with individual susceptibility to skin cancer and haematological malignancies. Moreover, the effect of the rs12203592 polymorphism on skin cancer risk was particularly prominent among Caucasians. Further functional research should be performed to validate the association.

Angiotensin-converting enzyme gene polymorphisms and risk for sporadic Alzheimer's disease: a meta-analysis.

Numerous studies have tested for associations between common polymorphisms of the angiotensin-converting enzyme gene and sporadic Alzheimer disease (SAD), but results have been inconclusive. Using meta-analysis, our study aimed to clarify the nature of the genetic risks contributed by the three polymorphisms (rs4291, rs4343, rs1800764) for developing SAD. Through searching of Pubmed, Embase, Alzgene and manually searching relevant references, a total of 14 articles with 26 independent studies were included. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association studies. The heterogeneity across the studies was tested, as was publication bias. We observed significant association between SNP rs4291 and SAD using allelic comparison (OR = 1.08, 95% CI 1.03-1.14), homozygote comparison (OR = 1.16, 95% CI 1.04-1.30) and the recessive model (OR = 1.10, 95% CI 1.02-1.18). Association with SNP rs1800764 was revealed but it was not sufficiently robust to withstand the Benjamini-Hochberg method and stepdown Bonferroni correction. Significant association was not identified in the analysis for SNP rs4343. In subgroup analyses, the risk of SAD associated with SNP rs4291 appeared to be significant among Caucasians and in older cases (mean age ≥75 years). Our results confirmed a significant but modest association between SNP rs4291 and SAD susceptibility. Further study of the pathogenetic characteristics of this polymorphism and independent confirmation of the association in larger studies are warranted.

Endothelial nitric oxide synthase (eNOS) 4b/a gene polymorphisms and coronary artery disease: evidence from a meta-analysis.

A variety of studies have suggested that the 4b/a polymorphism in the endothelial nitric oxide synthase (eNOS) was associated with coronary artery disease (CAD) risk. However, the data remain conflicting. The aim of the present meta-analysis was to estimate the overall association between risk of CAD and eNOS 4b/a polymorphism. Case-control, cohort or cross-sectional studies evaluating the association between eNOS 4b/a polymorphism and CAD susceptibility were systematically identified in PubMed up to 31 October 2013. Pooled odds ratios (OR) and corresponding 95% confidence intervals (CIs) were calculated to assess the association in overall and subgroup analyses. A total of 10,617 cases and 8302 controls from 37 studies were included in the study. The results of overall analysis revealed significant positive associations between CAD risk and eNOS 4b/a polymorphism in homozygote comparisons (OR = 1.47, 95% CI = 1.16–1.87), heterozygote comparisons (OR = 1.14, 95% CI = 1.02–1.27) and dominant models (OR = 1.18, 95% CI = 1.06–1.33). In subgroup analyses, similar associations were identified in African individuals, as determined using population-based source subgroups and noted in small-and-moderate sample size subgroups (case sample size or control sample size <500). The current meta-analysis revealed that eNOS 4b/a polymorphisms could be a risk factor for developing CAD, particularly in African populations and population-based subgroups.

The effect of XPD polymorphisms on digestive tract cancers risk: a meta-analysis.

BackgroundThe Xeroderma pigmento-sum group D gene (XPD) plays a key role in nucleotide excision repair. Single nucleotide polymorphisms (SNP) located in its functional region may alter DNA repair capacity phenotype and cancer risk. Many studies have demonstrated that XPD polymorphisms are significantly associated with digestive tract cancers risk, but the results are inconsistent. We conducted a comprehensive meta-analysis to assess the association between XPD Lys751Gln polymorphism and digestive tract cancers risk. The digestive tract cancers that our study referred to, includes oral cancer, esophageal cancer, gastric cancer and colorectal cancer.MethodsWe searched PubMed and EmBase up to December 31, 2012 to identify eligible studies. A total of 37 case-control studies including 9027 cases and 16072 controls were involved in this meta-analysis. Statistical analyses were performed with Stata software (version 11.0, USA). Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association.ResultsThe results showed that XPD Lys751Gln polymorphism was associated with the increased risk of digestive tract cancers (homozygote comparison (GlnGln vs. LysLys): OR = 1.12, 95% CI = 1.01–1.24, P = 0.029, P heterogeneity = 0.133). We found no statistical evidence for a significantly increased digestive tract cancers risk in the other genetic models. In the subgroup analysis, we also found the homozygote comparison increased the susceptibility of Asian population (OR = 1.28, 95% CI = 1.01–1.63, P = 0.045, P heterogeneity = 0.287). Stratified by cancer type and source of control, no significantly increased cancer risk was found in these subgroups. Additionally, risk estimates from hospital-based studies and esophageal studies were heterogeneous.ConclusionsOur meta-analysis suggested that the XPD 751Gln/Gln genotype was a low-penetrate risk factor for developing digestive tract cancers, especially in Asian populations.

The association between hypoxia-inducible factor-1 α gene G1790A polymorphism and cancer risk: a meta-analysis of 28 case-control studies.

PurposeHypoxia-inducible factor-1 (HIF-1) is a key transcription factor that regulates the cellular adaptation to hypoxia. HIF-1α gene single nucleotide polymorphisms (SNPs) are implicated to be associated with cancer risks. However, results from the published studies remained inconclusive. The aim of this study is to investigate the relationship of HIF-1α gene G1790A polymorphism with cancer using meta-analysis.MethodsA comprehensive search in Pubmed, EMBASE and China National Knowledge Infrastructure (CNKI) was conducted to identify all publications on the association between this polymorphism and cancer until December 13, 2013. Odds ratios (OR) with 95% confidence intervals (95% CI) were used to evaluate the strength of this association. Association between lymph node metastasis and G1790A was also investigated.ResultsA total of 5985 cases and 6809 controls in 28 case–control studies were included in this meta-analysis. The A allele of HIF-1α gene G1790A polymorphism was found to be significantly associated with increased cancer risk in four genetic models: AA + AG vs. GG (dominant model OR = 1.85, 95% CI = 1.27-2.69), AA vs. AG + GG (recessive model OR = 5.69, 95% CI = 3.87-8.37), AA vs. GG (homozygote comparison OR = 6.63, 95% CI = 4.49-9.79), and AG vs. GG (heterozygote comparison OR = 2.39, 95% CI = 1.53-3.75). This variant was also significantly associated with higher risks of pancreatic cancer, head and neck cancer, lung cancer and renal cell carcinoma. However, the A allele of G1790A was not significantly associated with increased lymph node metastasis in the dominant model by overall meta-analysis.ConclusionsOur meta-analysis suggests that the substitution of G with A of HIF-1α gene G1790A polymorphism is a risk factor of cancer, especially for pancreatic cancer, lung cancer, renal cell carcinoma and head and neck cancer. The association is significant in Asian, Caucasian population and public based control subgroups. However, it’s not associated with risk of lymph node metastasis.