Genetic polymorphisms in the cytochrome P450 1A1, glutathione S-transferase M1 and T1, and susceptibility to colon cancer

Several polymorphic cytochrome P-450 and glutathione S-transferase (GST) enzymes are involved in the activation and detoxification of many potential carcinogens and may therefore be important in susceptibility to cancer induction. CYP1A1 MspI, GSTM1, and GSTT1 are polymorphic enzymes and some alleles have been correlated with an increased risk of developing some cancers. In the present study, we examined possible associations between genetic polymorphisms of CYP1A1 MspI, GSTM1, and GSTT1 and colon cancer in a United Kingdom population. An excess of CYP1A1 MspI, and GSTM1 null genotypes was observed amongst colon cancer patients, although this did not reach the level of statistical significance. We found no significant increase in the risk of colon cancer for either CYP1A1 MspI (OR = 1.39; 95%CI: 0.46-4.21) or GSTM1 null (OR = 1.41; 95%CI: 0.76-3.01) genotypes. Individuals with GSTT1 null genotype had no association with colon cancer (OR = 0.42; 95%CI: 0.09-2.02). No significant association was observed in the site of colon cancer (proximal vs. distal). This study suggests that the polymorphisms of CYP1A1 MspI, GSTM1, and GSTT1 are not associated with a significant risk of developing colon cancer in a United Kingdom population.