OBJECTIVETo evaluate the published data on association between present/null polymorphism of glutathione S-transferase M1 (GSTM1) and breast cancer risk in Chinese population in order to abttain a more precise and comprehensive estimation of the relationship.

METHODSA meta-analysis was performed to investigate the association between GSTM1 polymorphism and susceptibility to breast cancer in Chinese population by searching Pubmed, Embase, Cochrane library, CNKI, VIP, Wanfang and CBD database. The data were screened according to the inclusion and exclusion criteria, and extracted, and the quality of included studies was evaluated. The pooled odds ratios (OR) with 95% confidence intervals (95%CI) were calculated using RevMan 5.2 and Stata 12.0 software. Publication bias and sensitivity analysis were also assessed.

RESULTSA total of 15 case-control studies involving 5,176 cases and 5 890 controls were included in the meta-analysis. The results showed that individuals with GSTM1 null genotype harbored a significantly increased risk of breast cancer compared to that with GSTM1 non-null genotype in Chinese population (OR=1.34, 95%CI=1.12-1.60, P=0.002). The subgroup analysis by region revealed that the individuals with GSTM1 null genotype were significantly associated with an increased risk of breast cancer in southern and northern China populations (southern: OR=1.14, 95%CI=1.01-1.28, P=0.03; northern: OR=2.65, 95%CI=2.04-3.34, P<0.01).

CONCLUSIONThe current meta-analysis demonstrates that the GSTM1 polymorphism is significantly associated with susceptibility to breast cancer in Chinese population, and the GSTM1-deficit may increase the risk of breast cancer.