Association of glutathione S-transferase M1 polymorphisms in the colorectal cancer risk: A meta-analysis

Purpose: The glutathione S-transferase M1 (GSTM1) as a member of phase II detoxification enzymes is expressed in many tissues and plays a critical role in preventing the occurrence of cancer. Published data regarding the associations between the GSTM1 polymorphism and colorectal cancer (CRC) risk are inconclusive. Materials and Methods: A meta-analysis of 55 case–control studies involving 17,498 cases and 26,441 controls were performed to assess the strength of association using odds ratio (OR) with 95% confidence interval (CI). Results: The meta-analysis of those studies suggested that GSTM1 null genotype was significantly associated with CRC risk (OR = 1.13, 95% CI = 1.06–1.20, P P = 0.001), Asians (OR = 1.11, 95% CI = 1.02–1.22, P = 0.02), and mixed group (OR = 1.01, 95% CI = 0.90–1.14, P = 0.85). In the subgroup analysis by study design, significant elevated risks were associated with GSTM1 null genotype in hospital-based case–control study group (OR = 1.20, 95% CI = 1.10–1.31, and P P = 0.43). Conclusions: Based on our meta-analysis, the GSTM1 null genotype is a risk factor for CRC.