We evaluated the effect of meat consumption and cigarette smoking in combination with N-acetyltransferases 1 and 2 (NAT1 and NAT2), and glutathione S-transferase M1 (GSTM1) genotypes on colorectal cancer.
We found no association with colorectal cancer risk with NAT2 genotype or any of the other polymorphic genes associated with the metabolism and disposition of heterocyclic amine carcinogens.
Epidemiological studies based on phenotype determination have long indicated the importance of the NAT2 active phenotype as a susceptibility factor in colorectal cancer.
Associations between slow NAT2 acetylator genotypes and urinary bladder cancer and between rapid NAT2 acetylator genotypes and colorectal cancer are the most consistently reported.
Our findings indicate that NAT1 and NAT2 genotypes may contribute jointly to individual susceptibility and that heterocyclic aromatic amines may play an important role in colorectal cancer associated with red meat and possibly also exposure to environmental tobacco smoke.
Collectively, patients with the NAT2 fast acetylator genotype were more prone to colorectal cancer and reflected the possibility that exposure to heterocyclic amines may contribute to colorectal cancer development in Taiwan, especially in Taiwanese females.
NAT2 fast acetylator genotype and MGMT promoter methylation may contribute to gender difference in K-RAS mutation occurrence in Taiwanese colorectal cancer.