An updated meta-analysis of the association between GSTM1 polymorphism and colorectal cancer in Asians.

Glutathione S-transferases (GSTs) are a large family of phase II detoxification enzymes that are expressed in many tissues and play critical roles in protecting hosts against cancer. The association of glutathione S-transferase M1 (GSTM1) polymorphism with susceptibility to colorectal cancer in Asians has not been well established. We performed a meta-analysis to quantitatively assess the association between GSTM1 polymorphism and colorectal cancer in Asians. We systematically searched the PubMed and Embase databases to identify the eligible studies. Finally, 17 eligible studies with 5,907 cases and 9,726 controls were included into the meta-analysis. The pooled odds ratio (OR) with its 95 % confidence intervals (95 %CI) was used to assess the association. The meta-analysis of those included studies suggests that GSTM1 null genotype was significantly associated with colorectal cancer risk in Asians (OR = 1.14, 95 %CI = 1.013-1.29, P = 0.03). The cumulative meta-analyses showed a trend of an obvious association between the GSTM1 null genotype and risk of colorectal cancer in Asians as information accumulated by year. Thus, there is an obvious association between the GSTM1 null genotype and risk of colorectal cancer in Asians.