RESUMEN
BACKGROUND: Published data on the association between present/null polymorphism of glutathione S-transferase M1 (GSTM1) and breast cancer risk are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis in the Chinese population was performed. METHODS: PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure (CNKI), and Chinese Biology Medicine (CBM) were searched. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association between the GSTM1 present/ null polymorphism and breast cancer risk. RESULTS: A total of 17 studies including 5323 breast cancer cases and 7196 controls were involved in this meta-analysis. Overall, a significant association (OR = 1.28, 95%CI: 1.09 - 1.51) was found between the null GSTM1 and breast cancer risk when all studies in Chinese population were pooled into the meta-analysis. In subgroup analyses stratified by geographic areas and source of controls, the same results were observed in mainland China (OR = 1.42, 95% CI = 1.12 - 1.81) and hospital-based studies (OR = 1.55, 95% CI = 1.20 - 2.00). CONCLUSIONS: This meta-analysis suggests that the GSTM1 null genotype is a low-penetrant risk factor for developing breast cancer in the Chinese population.