Quantitative assessment of the association between glutathione S-transferase P1 Ile105Val polymorphism and bladder cancer risk

Previous studies investigating the association between glutathione S-transferase P1 (GSTP1) Ile105Val polymorphism and bladder cancer risk reported controversial results. This study aimed to quantify the strength of the association between GSTP1 Ile105Val polymorphism and bladder cancer risk by performing a meta-analysis. We searched the PubMed, Embase, and Wanfang databases for publications on the association between GSTP1 Ile105Val polymorphism and bladder cancer risk. We estimated the pooled odds ratios (ORs) with their confidence intervals (95 %CIs) to assess the association. Twenty-five individual studies with a total of 12,360 subjects were finally included. Meta-analysis of all 25 studies showed that GSTP1 Ile105Val polymorphism was associated with increased risk of bladder cancer risk under four genetic comparison models (for G versus A, random-effect OR?=?1.19, 95 %CI 1.05–1.35; for GG versus AA, random-effect OR?=?1.49, 95 %CI 1.12–1.97; for GG/GA versus AA, random-effect OR?=?1.20, 95 %CI 1.03–1.39; for GG versus GA/AA, random-effect OR?=?1.41, 95 %CI 1.10–1.80). Sensitivity analysis showed that GSTP1 Ile105Val polymorphism was still associated with bladder cancer risk under three genetic comparison models (for G versus A, random-effects OR?=?1.13, 95 %CI 1.01–1.26; for GG versus AA, random-effects OR?=?1.29, 95 %CI 1.01–1.65; for GG versus GA/AA, random-effects OR?=?1.19, 95 %CI 1.04–1.35). No evidence of publication bias was observed. This meta-analysis shows that there is an obvious association between GSTP1 Ile105ValIle105Val polymorphism and bladder cancer risk, and GSTP1 ILE105VAL polymorphism contributes to bladder cancer risk.     

Quantitative assessment of the association between GSTP1 gene Ile105Val polymorphism and susceptibility to hepatocellular carcinoma

Glutathione S-transferase P1 (GSTP1) gene Ile105Val polymorphism has been suggested to be involved in the development of cancer. However, the results from the studies regarding the association between GSTP1 Ile105Val polymorphism and hepatocellular carcinoma risk have been inconsistent. Thus, we performed a meta-analysis to investigate the association. Published literature from PubMed, Chinese Biomedical Literature, and Wanfang databases was searched for eligible publications. Pooled odds ratios (ORs) with 95 % confidence intervals (95 %CIs) were calculated using random- or fixed-effects model. Six studies with a total of 1,843 participants were finally included into this meta-analysis. The results suggested there was no association between GSTP1 Ile105Val polymorphism and hepatocellular carcinoma risk under all genetic models (for ValVal vs. IleIle, OR?=?0.79, 95 %CI 0.48–1.29, P?=?0.341; for IleVal vs. IleIle, OR?=?1.05, 95 %CI 0.84–1.30, P?=?0.678; for the dominant model, OR?=?0.91, 95 %CI 0.68–1.20, P?=?0.498; and for the recessive model, OR?=?0.76, 95 %CI 0.47–1.24, P?=?0.269). Subgroup analyses by ethnicity showed there was also no association between GSTP1 Ile105Val polymorphism and hepatocellular carcinoma risk in Asians under all genetic models (All P values were more than 0.05), but GSTP1 Ile105Val polymorphism was associated with decreased risk of hepatocellular carcinoma in European under the recessive model (ValVal vs. IleVal/IleIle) (OR?=?0.44, 95 %CI 0.20–0.98, P?=?0.044). In conclusion, the meta-analysis suggests that there is little evidence for the association between GSTP1 Ile105Val polymorphism and hepatocellular carcinoma risk. However, more well-designed studies are needed to further assess this association.     

Association between the GSTP1 Ile105Val polymorphism and prostate cancer risk: a systematic review and meta-analysis

Many studies have reported the role of glutathione S-transferase P1 (GSTP1) Ile105Val polymorphism with prostate cancer (PCa) risk. However, these studies have yielded conflicting results. Hence, we performed this meta-analysis to investigate the association between GSTP1 Ile105Val polymorphism and PCa in different inheritance models. A total of 13 eligible studies were pooled into this meta-analysis. There was significant association between the GSTP1 Ile158Val variant genotypes and PCa for Ile/Ile vs Val/Val comparison [odds ratio (OR)?=?0.705; I ²?=?63.7 %; 95 % confidence interval (95 % CI)?=?0.508–0.977], Ile/Val vs Val/Val comparison (OR?=?0.736; I ²?=?8.0 %; 95 % CI?=?0.613–0.883), and dominant model (OR?=?0.712; I ²?=?45.5 %; 95 % CI?=?0.555–0.913). However, no associations were detected for other genetic models. In the stratified analysis by ethnicity, significant associations between GSTP1 Ile105Val polymorphism and PCa risk were also found among Caucasians (Ile/Ile vs Val/Val comparison OR?=?0.818, I ²?=?0.0 %, 95 % CI?=?0.681–0.982; Ile/Val vs Val/Val comparison OR?=?0.779, I ²?=?0.0 %, 95 % CI?=?0.651–0.933; and dominant model OR?=?0.794, I ²?=?0.0 %, 95 % CI?=?0.670–0.941), while there were no associations found for other genetic models. However, no associations were found in Asians and African-Americans for all genetic models when stratified by ethnicity. In conclusion, our meta-analysis indicates that GSTP1 Ile105Val polymorphisms contributed to the PCa susceptibility. However, a study with the larger sample size is needed to further evaluate gene–environment interaction on GSTP1 Ile105Val polymorphisms and PCa risk.     

The polymorphism of EGFR 142285G > A exerts no risk effect on breast cancer

The association between the epidermal growth factor receptor (EGFR) 142285G?>?A polymorphism and the susceptibility to breast cancer is unclear. We conducted a meta-analysis of all published studies to estimate the association of EGFR 142285G?>?A polymorphism and breast cancer risk. Systematic computerized searching of the PubMed, Web of Science, and Wanfang databases was performed for relevant publications. Overall, there were three eligible case–control studies with 1,360 cases and 1,522 controls included into our study. The pooled ORs showed that the EGFR 142285G?>?A variant genotypes did not increase or decrease the risk of breast cancer under the following gene models: A vs. G, OR?=?1.07, 95 % CI 0.96–1.19, P _OR?=?0.240; AA vs. GG, OR?=?1.14, 95 % CI 0.91–1.42, P _OR?=?0.239; GA vs. GG, OR?=?0.99, 95 % CI 0.83–1.17, P _OR?=?0.892; GA?+?AA vs. GG, OR?=?1.03, 95 % CI 0.87–1.21, P _OR?=?0.727; AA vs. GG?+?GA, OR?=?1.17, 95 % CI 0.97–1.42, P _OR?=?0.096. The between-study heterogeneity was not significant among all studies. The current meta-analysis showed no evidence for significant association between EGFR 142285G?>?A polymorphism and breast cancer risk. Subsequent studies with large sample size are needed for further elucidation.     

Genetic polymorphisms in glutathione S-transferases P1 (GSTP1) Ile105Val and prostate cancer risk: a systematic review and meta-analysis

Numerous epidemiological studies have evaluated the association between the glutathione S-transferases P1 (GSTP1) Ile105Val polymorphisms and prostate cancer (PCa) risk. However, these studies have yielded conflicting results. A comprehensive search was conducted through researching MEDLINE, PubMed, Web of Science, and EMBASE, and a total of 13 studies including 3,227 cases and 3,945 controls were identified. A meta-analysis was performed to obtain a summary of estimated odds ratios (ORs) and 95 % confidence intervals (CIs) of GSTP1 polymorphisms for PCa, with attention to study quality and publication bias. The GSTP1 Ile158Val variant genotypes are less associated with increased risk of PCa for the homozygote model (Val/Val vs Ile/Ile: OR?=?1.42; I ²? =?63.7 %; 95 % CI?=?1.02–1.97) and the recessive model (OR?=?1.41; I ²? =?45.5 %; 95 % CI?=?1.10–1.80). However, no associations were detected for other genetic models. In the stratified analysis by ethnicity, significant associations between GSTP1 Ile105Val polymorphism and PCa risk were also found among Caucasians for Val/Val vs Ile/Ile comparison (OR?=?1.22; I ²? =?0.0 %; 95 % CI?=?1.02–1.47) and for the recessive model (OR?=?1.26; I ²? =?0.0 %; 95 % CI?=?1.06–1.49), while there were no associations found for other genetic models. However, no associations were found in Asians and African-Americans for all genetic models when stratified by ethnicity. In conclusion, our meta-analysis provides evidence that GSTP1 Ile105Val gene polymorphisms contributed to PCa susceptibility.     

Glutathione S-transferase P1 Ile105Val polymorphism contributes to increased risk of gastric cancer in East Asians

Glutathione S-transferase P1 (GSTP1) is an important enzyme playing critical roles in the phase II detoxification pathway. There were many studies investigating the association between GSTP1 gene Ile105Val polymorphism and gastric cancer risk, but studies from East Asians reported inconsistent findings. We performed a meta-analysis to investigate the association in East Asians. Published literature from PubMed and Chinese Biomedical Literature databases were searched for eligible publications. Pooled odds ratios (ORs) with 95 % confidence intervals (95 %CIs) were calculated using random or fixed-effect model according the between-study heterogeneity. A total of 12 studies with 2,552 cases and 5,474 controls were finally included into the meta-analysis. Meta-analysis of those 12 studies showed that there was an obvious association between GSTP1 Ile105Val polymorphism and gastric cancer risk in East Asians under three genetic models (for valine vs. isoleucine, OR?=?1.32, 95 %CI 1.05–1.66, P?=?0.015; for ValVal vs. IleIle, OR?=?2.00, 95 %CI 1.34–2.98, P?=?0.001; for the recessive model, OR?=?1.96, 95 %CI 1.35–2.83, P?<?0.001). Sensitivity analysis by removing one study at a time suggested the pooled results were stable under the three genetic models above. There was no risk of publication bias. In conclusion, the meta-analysis suggests that there is a strong evidence for the association between GSTP1 Ile105Val polymorphism and increased risk of gastric cancer in East Asians and contributes to increased risk of gastric cancer in East Asians.     

Tumor necrosis factor-α 238 G/A polymorphism and gastric cancer risk: a meta-analysis

Though many studies were performed to assess the association between tumor necrosis factor-α (TNF-α) 238 G/A polymorphism and gastric cancer risk, there were no conclusive findings. A meta-analysis of previous published studies was performed to get a comprehensive assessment of the association between TNF-α 238 G/A polymorphisms and gastric cancer. The pooled odds ratios (ORs) and 95 % confidence intervals (95 % CIs) were calculated to assess the association. Fifteen studies with a total of 7,795 participants were finally included into this meta-analysis. Overall, there was an obvious association between TNF-α 238 G/A polymorphism and increased risk of gastric cancer (A vs. G: OR?=?1.32, 95 % CI 1.02–1.72, P?=?0.036; GA vs. GG: OR?=?1.32, 95 % CI 1.01–1.72, P?=?0.042; and AA/GA vs. GG: OR?=?1.34, 95 % CI 1.02–1.76, P?=?0.036). Subgroup analysis by ethnicity showed the statistically significant association between TNF-α 238 G/A polymorphism and gastric cancer was limited to Asian populations (A vs. G: OR?=?1.59, 95 % CI 1.29–1.97, P?<?0.001; GA vs. GG: OR?=?1.63, 95 % CI 1.29–2.04, P?<?0.001; and AA/GA vs. GG: OR?=?1.64, 95 %CI 1.31–2.05, P?<?0.001), and there was no obvious association in Caucasians. In conclusion, TNF-α 238 G/A polymorphism is significantly associated with increased risk of gastric cancer, especially in Asians.     

Associations between Fas/FasL polymorphisms and susceptibility to cervical cancer: a meta-analysis

Genetic polymorphisms in the Fas/Fas ligand (FasL) gene were proposed to be associated with susceptibility to cervical cancer, but previous studies reported controversial findings. We performed a meta-analysis to assess the associations between Fas/FasL polymorphisms and susceptibility to cervical cancer. We carried out a literature search in PubMed and Embase databases for studies on the associations between Fas/FasL polymorphisms and susceptibility to cervical cancer. The associations were assessed by odds ratio (OR) together with its 95 % confidence intervals (CIs). Eleven individual studies with a total of 6,919 subjects were finally included into the meta-analysis. Overall, there was no association between Fas 1377G?>?A polymorphism and susceptibility to cervical cancer (A vs. G: OR?=?0.99, 95 % CI 0.88–1.12, P?=?0.91; AA vs. GG: OR?=?1.00, 95 % CI 0.76–1.32, P?=?0.99; AA/GA vs. GG: OR?=?0.95, 95 % CI 0.81–1.12, P?=?0.54; AA vs. GG/GA: OR?=?1.11, 95 % CI 0.85–1.43, P?=?0.45). In addition, there was also no association between FasL 844 T?>?C polymorphism and susceptibility to cervical cancer (C vs. T: OR?=?1.12, 95 % CI 0.91–1.36, P?=?0.28; CC vs. TT: OR?=?1.17, 95 % CI 0.90–1.51, P?=?0.24; CC/TC vs. TT: OR?=?1.13, 95 % CI 0.92–1.39, P?=?0.24; CC vs. TT/TC: OR?=?1.11, 95 % CI 0.83–1.50, P?=?0.47). In subgroup analysis by ethnicity, there were also no associations between Fas/FasL polymorphisms and susceptibility to cervical cancer in Asians and Africans. In conclusion, Fas 1377G?>?A polymorphism and FasL 844 T?>?C polymorphism are both not associated with susceptibility to cervical cancer.     

A pooled analysis of the ERCC2 Asp312Asn polymorphism and esophageal cancer susceptibility

Published data regarding the association between the excision repair cross-complimentary group 2 (ERCC2) Asp312Asn polymorphisms and esophageal cancer susceptibility remained controversial. This meta-analysis of literatures was performed to assess the strength of association between the ERCC2 and esophageal cancer susceptibility using random effects model. We systematically searched PubMed, Embase and Web of Science with a time limit of September 15, 2013. Summary odds ratios (ORs) with 95 % confidence intervals (CIs) were used to assess the strength of association between the ERCC2 Asp312Asn polymorphism and esophageal cancer susceptibility using random effects model. A total of seven case–control studies including 1,831 cases and 2,728 controls were included for analysis. Overall, a significant association was found between ERCC2 Asp312Asn polymorphism and esophageal cancer susceptibility for GA vs. GG (OR?=?1.20, 95 % CI?=?1.03–1.40) and for the dominant model GA/AA vs. GG (OR?=?1.18, 95 % CI?=?1.03–1.35). However, the ERCC2 Asp312Asn polymorphism was a protective factor for AA vs. GA/GG (OR?=?0.63, 95 % CI?=?1.15–2.65) in esophageal squamous cell carcinoma. Our meta-analysis suggested that the ERCC2 Asp312Asn polymorphism might be associated with increased risk of esophageal adenocarcinoma and a protective factor for esophageal squamous cell carcinoma.     

Cyclin D1 (CCND1) G870A polymorphisms and cervical cancer susceptibility: a Meta-analysis based on Ten case–control studies

Many studies have evaluated the association between cyclin D1 (CCND1) G870A polymorphism and cervical cancer susceptibility. However, these studies showed inconsistent results. The aim of this study was to derive a more precise estimation of this association. We searched PubMed and Embase for related studies that had been published in English, and ten case–control studies with a total of 2,864 cases and 3,898 controls were finally identified to be eligible studies in the meta-analysis. The association was assessed by summarizing the odds ratios (ORs) with the corresponding 95 % confidence intervals (CIs). Overall, there was no significant association between cyclin D1 (CCND1) G870A polymorphism and cervical cancer risk (for the allele model A vs. G: OR?=?1.02, 95 % CI 0.88–1.19, p?=?0.76; for the co-dominant model AA vs. GG: OR?=?1.03, 95 % CI 0.75–1.41, p?=?0.85; for the dominant model AA?+?GA vs. GG: OR?=?1.00, 95 % CI 0.78–1.28, p?=?0.99; for the recessive comparison AA vs. GA?+?GG: OR?=?1.06, 95 % CI 0.85–1.32, p?=?0.62). In subgroup analysis by ethnicity, no significant difference was found in both Asians and Caucasians. In summary, the present meta-analysis provides evidence that genotypes for the cyclin D1 (CCND1) G870A polymorphism may be not associated with genetic susceptibility of cervical cancer.     

Association between FAS 1377G>A polymorphism and breast cancer susceptibility: a meta-analysis

Published studies on the association between FAS 1377G>A polymorphism and breast cancer susceptibility were inconclusive. To derive a more precise assessment of the association, a meta-analysis of published studies was performed. PubMed, Embase, and Web of Science were searched for eligible studies on the association between FAS 1377G>A polymorphism and breast cancer susceptibility. Five studies with a total of 2,905 cases and 3,090 controls were included into the meta-analysis. Overall, FAS 1377G>A polymorphism was significantly associated with increased susceptibility to breast cancer (for AA versus GG: odds ratio (OR)?=?1.39, 95 % confidence interval (95 % CI) 1.12–1.72, P?=?0.003; for AA/GA versus GG: OR?=?1.18, 95 % CI 1.06–1.32, P?=?0.004; for AA versus GG/GA: OR?=?1.28, 95 % CI 1.05–1.56, P?=?0.015). Subgroup analysis by ethnicity found that FAS 1377G>A polymorphism was significantly associated with increased susceptibility to breast cancer in Asians (for AA versus GG: OR?=?1.48, 95 % CI 1.16–1.89, P?=?0.001; for AA/GA versus GG: OR?=?1.24, 95 % CI 1.06–1.46, P?=?0.008; for AA versus GG/GA: OR?=?1.35, 95 % CI 1.08–1.69, P?=?0.008), but the association was not found in Caucasians. Therefore, the findings of the meta-analysis suggest that FAS 1377G>A polymorphism is significantly associated with increased susceptibility to breast cancer in Asians.     

Association between GSTP1 Ile105Val polymorphism and glioma risk: A systematic review and meta-analysis

Glutathione S-transferase P1 (GSTP1) gene Ile105Val polymorphism has been suggested to be involved in the development of glioma. However, the results from the studies regarding the association between GSTP1 Ile105Val polymorphism and glioma risk have been inconsistent. Thus, we performed a meta-analysis to investigate this association. Pooled odds ratios (ORs) with 95 % confidence intervals (95 %CIs) were calculated using random or fixed effects model. Nine studies with 2,078 cases and 3,970 controls were finally included into this meta-analysis. The results suggested there was no association between GSTP1 Ile105Val polymorphism and glioma risk under recessive model (OR?=?1.138, 95 %CI?=?0.966–1.341, P _{heterogeneity}?=?0.088, P?=?0.123). Subgroup analyses by ethnicity showed there was also no association between GSTP1 Ile105Val polymorphism and glioma risk in mixed populations under recessive model (OR?=?1.199, 95 %CI?=?0.928–1.549, P _{heterogeneity}?=?0.060, P?=?0.166) and Caucasian populations(OR?=?1.097, 95 %CI?=?0.885–1.360, P _{heterogeneity}?=?0.186, P?=?0.398). In conclusion, the meta-analysis suggests that there is no association between GSTP1 Ile105Val polymorphism and glioma risk. However, more well-designed and larger studies are needed to further assess this association.     

Association between tumor necrosis factor-α rs1800629 polymorphism and risk of gastric cancer: a meta-analysis

Gastric cancer is mainly initiated by inflammation and chronic superficial gastritis, and tumor necrosis factor-α (TNF-α) is an inflammatory cytokine which plays an important role in the inflammation. TNF-α rs1800629 G/A polymorphism was proposed to be associated with gastric cancer risk, but previous studies on Caucasians reported conflicting results. We performed a meta-analysis to comprehensively assess the association between TNF-α rs1800629 polymorphism and gastric cancer risk in Caucasians. The pooled odds ratio (OR) with 95 % confidence interval (95 % CI) was calculated to assess the association. Eleven case–control studies with 7,427 subjects were finally included into the meta-analysis. Overall, TNF-α rs1800629 polymorphism was significantly associated with the increased risk of gastric cancer under four genetic comparison models (A versus G: OR?=?1.32, 95 % CI 1.12–1.56, P?=?0.001; AA versus GG: OR?=?1.76, 95 % CI 1.37–2.26, P?<?0.001; AA versus GG/GA: OR?=?1.62, 95 % CI 1.27–2.07, P?<?0.001; AA/GA versus GG: OR?=?1.35, 95 % CI 1.14–1.60, P?=?0.001). Meta-analysis of those studies with high quality showed that TNF-α rs1800629 polymorphism was still significantly associated with the increased risk of gastric cancer under four genetic comparison models. There was no risk of publication bias in the meta-analysis. The meta-analysis suggests that TNF-α rs1800629 polymorphism is associated with the increased risk of gastric cancer in Caucasians.     

Cytochrome P450 1A1 Ile462Val polymorphism and oral carcinoma risk: an updated meta-analysis including 1,515 cases and 2,233 controls

Cytochrome P450 (CYP) 1A1 Ile462Val (exon7) polymorphism has been suggested to be a risk factor for several cancers. Published data on its association with oral cancer risk have generated conflicting results. Our previous meta-analysis containing data from prior to Jan 2008 regarding this issue failed to find a significant association between CYP1A1 Ile462Val variation and oral cancer susceptibility. An updated meta-analysis with eligible studies for the period up to May 2012 was conducted. Separate analyses on ethnicity and source of controls were also performed. A total of 13 case?Ccontrol studies comprising 1,515 cases and 2,233 controls were lastly selected for analysis. Compared with the previous meta-analysis, the overall data also failed to indicate a significant association of CYP1A1 Ile462Val polymorphism with oral cancer risk (Val/Val vs. Ile/Ile??OR?=?1.46; 95?% CI?=?0.96?C2.24; dominant model??OR?=?1.01; 95?% CI?=?0.81?C1.25; and recessive model??OR?=?1.46; 95?% CI?=?0.96?C2.23). However, in the subgroup analysis by ethnicity, increased cancer risk was observed among Asians under the additive and recessive models (Val/Val vs. Ile/Ile??OR?=?1.74; 95?% CI?=?1.04?C2.90 and recessive model??OR?=?1.73; 95?% CI?=?1.04?C2.87), inconsistent with the previous meta-analysis. Collectively, the data of the present study suggest that CYP1A1 variant Val/Val alleles might modify the susceptibility to oral cancer among Asians. Further well-designed investigations with large sample sizes are required to confirm this conclusion.     

Regulator of telomere elongation helicase 1 (RTEL1) rs6010620 polymorphism contribute to increased risk of glioma

Regulator of telomere elongation helicase 1 (RTEL1) is critical for genome stability and tumor avoidance. Many studies have reported the associations of RTEL1 rs6010620 with glioma risk, but individually published results were inconclusive. This meta-analysis was performed to quantitatively summarize the evidence for such a relationship. The PubMed, Embase, and Web of Science were systematically searched to identify relevant studies. The odds ratio (OR) and 95 % confidence interval (95 % CI) were computed to estimate the strength of the association using a fixed or random effects model. Ten studies were eligible for meta-analysis including data on glioma with 6,490 cases and 9,288 controls. Overall, there was a significant association between RTEL1 rs6010620 polymorphism and glioma risk in all four genetic models (GG vs. AA: OR?=?1.87, 95 % CI?=?1.60–2.18, P _{heterogeneity} ?=?0.552; GA vs. AA: OR?=?1.30, 95 % CI?=?1.16–1.46, P _{heterogeneity} ?=?0.495; dominant model—GG?+?GA vs. AA: OR?=?1.46, 95 % CI?=?1.31–1.63, P _{heterogeneity} ?=?0.528; recessive model—GG vs. GA?+?AA: OR?=?1.36, 95 % CI?=?1.27–1.46, P _{heterogeneity} ?=?0.093). Subgroup analyses by ethnicity showed that RTEL1 rs6010620 polymorphism resulted in a higher risk of glioma among both Asians and Caucasians. In the stratified analysis by ethnicity and source of controls, significantly increased risk was observed for Asians and Europeans in all genetic models, population-based studies in all genetic models, and hospital-based studies in three genetic models (heterozygote comparison, homozygote comparison, and dominant model). Our meta-analysis suggested that RTEL1 rs6010620 polymorphism is likely to be associated with increased glioma risk, which lends further biological plausibility to these findings.     

Glutathione S-transferase P1 Ile105Val polymorphism and breast cancer risk: a meta-analysis involving 34,658 subjects

Glutathione S-transferase P1 (GSTP1) is involved in a wide range of detoxifying reactions. Any alteration in the structure, function, or expression of GSTP1 gene may alter the ability of a cell to inactivate carcinogens or mutagens, and thus modify an individual’s risk to cancer. Previous epidemiological studies on the potential association between GSTP1 Ile105Val polymorphism and breast cancer risk have produced inconsistent results. In order to drive a more precise estimation of this association, we performed a meta-analysis of 30 published case–control studies including 15,901 cases and 18,757 controls. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association. The results of this meta-analysis showed that GSTP1 Ile105Val polymorphism was not associated with breast cancer susceptibility in overall population. However, in subgroup analysis by ethnicity, we found a significant association among Asian population (for Val/Val vs. Ile/Ile: OR 1.27, 95% CI 1.02–1.83; for the recessive model Val/Val vs. Ile/Ile + Ile/Val: OR 1.42, 95% CI 1.20–1.69). When stratified by study design, significantly elevated susceptibility to breast cancer was found among hospital-based studies (for Val/Val vs. Ile/Ile: OR 1.38, 95% CI 1.16–1.63; for recessive model Val/Val vs. Ile/Val + Ile/Ile: OR 1.31, 95% CI 1.12–1.55; for dominant model: Val/Val + Ile/Val vs. Ile/Ile: OR 1.10, 95% CI 1.02–1.19). In conclusion, our meta-analysis suggests that GSTP1 Ile105Val polymorphism may increase susceptibility to breast cancer in Asian population.     

FAS−1377 A/G polymorphism in breast cancer: a meta-analysis

FAS is a cell surface receptor involved in apoptotic signaling in many cell types including cells of the immune system. The ?1377 A/G polymorphism of FAS gene has been detected in breast cancer. However, the published evidence regarding the ?1377 A/G polymorphism and breast cancer risk has generated controversial results. We performed a meta-analysis of five case–control association studies totaling to 5,995 study subjects including 2,905 cases and 3,090 controls. The combined odd ratios (ORs) with its 95 % CIs were used to assess the association of the ?1377 A/G polymorphism correlated with breast cancer susceptibility with the fixed-effects model. The combined results showed significantly increased risk associated with the ?1377 A/G polymorphism under AA vs. GG genetic model (OR?=?1.28, 95 % CI?=?1.04–1.58; heterogeneity test: P?=?0.614, I ² ?=?0.0 %), AA vs. GA + GG genetic model (OR?=?1.24, 95 CI?=?1.02–1.51; heterogeneity test: P?=?0.349, I ² ?=?10.0 %), and allele model A vs. G (OR?=?1.10, 95%CI?=?1.02–1.20; heterogeneity test: P?=?0.422, I ² ?=?0.0 %). Similarly, significant association was found in Asians. In stratified analyses by control source, a higher risk was indicated in the hospital-based studies rather than the population-based studies. This meta-analysis suggests that the ?1377 A/G polymorphism is likely to be associated with the risk of breast cancer, especially the A allele in Asians.     

A systemic assessment of the association between tumor necrosis factor alpha 308 G/A polymorphism and risk of cervical cancer

Tumor necrosis factor alpha (TNF-α) is a multifunctional cytokine which plays an important role in the human immune response against various pathogens, and there may be a relationship between TNF-α 308 G/A polymorphism and cervical cancer risk. We performed a meta-analysis to get a systemic assessment of the association between TNF-α 308 G/A polymorphism and cervical cancer risk. Electronic searches of PubMed, Embase, and Web of Science were performed for all publications on the association between TNF-α 308 G/A polymorphism and cervical cancer risk through October 26, 2012. The pooled odds ratios (ORs) with their 95 % confidence interval (95 % CIs) were calculated to assess the association. Fifteen studies with a total of 3,743 cervical cancer cases and 4,096 controls were finally included into the meta-analysis. Overall, TNF-α 308 G/A polymorphism was significantly associated with increased risk of cervical cancer under three main genetic comparison models (A vs. G, OR 1.20, 95 % CI 1.02–1.42, P?=?0.03; AA vs. GG, OR 1.31, 95 % CI 1.00–1.72, P?=?0.048; AA vs. GG/GA, OR 1.30, 95 % CI 1.00–1.71, P?=?0.05). Subgroup analysis by ethnicity further showed that there was a significant association between TNF-α 308 G/A polymorphism and increased risk of cervical cancer in Asians (AA vs. GG, OR 1.83, 95 % CI 1.05–3.20, P?=?0.034; AA vs. GG/GA, OR 1.84, 95 % CI 1.05–3.22, P?=?0.032). The meta-analysis suggests that TNF-α 308 G/A polymorphism is associated with increased risk of cervical cancer, and TNF-α 308 G/A mutant allele A is a risk factor of cervical cancer.     

Methylenetetrahydrofolate reductase polymorphisms and breast cancer risk in Chinese population: a meta-analysis of 22 case–control studies

The association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and breast cancer risk in the Chinese population has been widely reported, but results were inconsistent. In order to derive a more precise estimation of the relationship, a meta-analysis was performed. Eligible articles were identified through search of databases including Medline, PubMed, Web of Science, Embase, Chinese Biomedical Literature Database (CBM, Chinese), China National Knowledge Infrastructure (CNKI, Chinese), and Wangfang Database (Chinese). The association between the MTHFR polymorphism and breast cancer risk was conducted using odds ratios (ORs) and 95 % confidence intervals (95 % CIs). Finally, a total of 22 studies with 6,103 cases and 7,913 controls were included in our meta-analysis: 13 studies with 3,273 cases and 4,419 controls for C677T polymorphism and 9 studies with 2,830 cases and 3,494 controls for A1298C polymorphism. With regard to C677T polymorphism, significant association was found with breast cancer risk under three models (T vs. C: OR?=?1.12, 95 % CI?=?1.02–1.23, P?=?0.015; TT vs. CC: OR?=?1.35, 95 % CI?=?1.10–1.67, P?=?0.005; TT vs. CC/CT: OR?=?1.37, 95 % CI?=?1.11–1.70, P?=?0.004). There was no significant association found between A1298C polymorphism and breast cancer risk under all genetic models (C vs. A: OR?=?0.96, 95 % CI?=?0.89–1.03, P?=?0.268; CC vs. AA: OR?=?0.98, 95 % CI?=?0.77–1.26, P?=?0.899; AC vs. AA: OR?=?0.95, 95 % CI?=?0.88–1.02, P?=?0.174; CC vs. AC/AA: OR?=?1.00, 95 % CI?=?0.78–1.28, P?=?0.996, CC/AC vs. AA: OR?=?0.96, 95 % CI?=?0.89–1.02, P?=?0.196). In summary, during this meta-analysis, we found that MTHFR C677T polymorphism was significantly associated with breast cancer risk in the Chinese population. Meanwhile, MTHFR A1298C polymorphism was not associated with breast cancer risk in the Chinese population.     

Vascular endothelial growth factor -634G/C and vascular endothelial growth factor -2578C/A polymorphisms and lung cancer risk: a case–control study and meta-analysis

Vascular endothelial growth factor (VEGF) is a major regulator of angiogenesis in the process of tumor growth and metastasis. In present study, we conducted a case–control study and meta-analysis to evaluate the genetic effects of VEGF -634G/C and VEGF -2578C/A polymorphisms and risk of lung cancer. A total of 175 subjects were recruited for case–control study and seven studies were included in the meta-analysis. Our case–control study showed that VEGF -634G/C polymorphism had no association with lung cancer risk (CC vs. GG: OR?=?0.88, 95 % CI?=?0.37–2.11), whereas there was an association between VEGF -2578CC genotype and decrease in lung cancer risk (CC vs. CA/AA: OR?=?0.52, 95 % CI?=?0.28–0.96). A meta-analysis was further performed and statistically similar results were obtained (CC vs. GG: OR?=?0.91, 95 % CI?=?0.60–1.39 for VEGF ?634; CC vs. AA: OR?=?0.53, 95 % CI?=?0.32–0.89 for VEGF ?2578). Our study showed that the variant genotypes of the VEGF -2578C/A polymorphism, but not the VEGF -634G/C polymorphism, was associated with lung cancer risk. More studies are needed to detect VEGF -634G/C and VEGF ?2578 polymorphisms and their association with lung cancer in different ethnic populations incorporated with environmental exposures.