Null genotype of glutathione S-transferase Tl contributes to colorectal cancer risk in the Asian population: a meta-analysis

Background and Aim: Previous studies investigating the association between the glutathione S‐transferase Tl (GSTT1) null genotype and colorectal cancer (CRC) risk in the Asian population have reported controversial results. Thus, a meta‐analysis was performed to clarify the effect of the GSTT1 null genotype on CRC risk in the Asian population. Methods: A comprehensive study was conducted, and 12 case‐control studies were finally included, involving a total of 4517 CRC cases and 6607 controls. Subgroup analyses were performed by the sample size. Results: A meta‐analysis of all 12 studies showed that the GSTT1 null genotype was significantly associated with an increased CRC risk in the Asian population (odds ratio OR] = 1.10, 95% confidence interval CI] = 1.02–1.19, the P‐value of the OR P_OR] = 0.02, the value of the heterogeneity analysis I²] = 42%). A more obvious association was observed after the heterogeneity was eliminated by excluding one study (OR = 1.15, 95% CI: 1.06–1.25, P_OR = 0.001, I² = 0%). This association was further identified by both subgroup analyses and a sensitivity analysis. Conclusions: This meta‐analysis suggests that the GSTT1 null genotype contributes to an increased colorectal cancer risk in the Asian population.