Association of glutathione S-transferase T1, M1, and P1 polymorphisms in the breast cancer risk: a meta-analysis

Background: Several case-control studies investigating the relationship between genetic polymorphisms of glutathione S-transferase (GST) M1, GSTT1, and GSTP1 (rs1695) and the risk of breast cancer have reported contradictory results. We therefore performed a meta-analysis to clarify this issue. Materials and methods: An updated meta-analysis using PubMed and Web of Knowledge databases for the eligible case-control studies was performed. Random- or fixed-effects model was used. Results: A total of 10,067 cancer cases and 12,276 controls in 41 independent case-control studies from 19 articles were included in this meta-analysis. Significant increase in risk of breast cancer for Asians was found in GSTM1-null genotype (P=0.012, odds ratio [OR] = 1.17, 95% confidence interval [CI] = 1.04-1.32) and GSTT1-null genotype (P=0.039, OR = 1.19, 95% CI = 1.01-1.41). In addition, our results showed that the GSTP1 (rs1695) polymorphisms can significantly increase the risk among Caucasians (P=0.042, OR = 1.16, 95% CI = 1.01-1.34). Sensitivity analysis and publication bias further confirmed the dependability of the results in this meta-analysis. Conclusion: Our results demonstrate that both GSTM1-and GSTT1-null polymorphisms are associated with an increased risk of breast cancer in Asians and that GSTP1 Val105Ile (rs1695) polymorphism is associated with an increased breast cancer risk in Caucasians.