Association between Glutathione S-Transferase T1, M1, and P1 Genotypes and the Risk of Colorectal Cancer

Glutathione S-transferases (GSTs) are enzymes which play an important role in theneutralization of toxic compounds and eradication of electrophilic carcinogens. Geneticpolymorphisms within the genes encoding for GSTs may therefore cause variations in theirenzyme activity, which may in turn influence the interindividual susceptibility to cancers. In this study, we aimed to investigate the association between genetic polymorphisms ofGSTT1, GSTM1, and GSTP1 and the risk of colorectal cancer (CRC) in 264 cases and 317controls in a Chinese population. Genotyping was performed by using multiplex PCR (forGSTT1 and GSTM1) and PCR-RFLP (for GSTP1) methods. The association between thepolymorphic genotypes and CRC risk was evaluated by deriving odds ratios (ORs) and 95%confidence intervals (CIs) using unconditional logistic regression analysis. Our resultsshowed that individuals with GSTT1 and GSTM1 null genotypes exhibited a higher risk ofCRC (GSTT1, OR,1.66; 95% CI, 1.20-2.31, P = 0.003; GSTM1, OR,1.57; 95% CI,1.13-2.18, P = 0.007), while no association was observed for GSTP1 (Pheterozygous = 0.790 or Pvariant= 0.261). Furthermore, individuals who simultaneously carried the null genotypes forboth GSTT1 and GSTM1 showed a stronger risk association (OR, 1.95; 95% CI, 1.33-2.85;P < 0.001). In conclusion, the GSTT1 and GSTM1 polymorphisms, but not GSTP1, maymodulate the CRC risk among Chinese.