Background: Genetic polymorphisms of metabolizing enzymes may affect the risk of cancer formation in humans. Since the diet can contain polycyclic aromatic hydrocarbons (PAHs) and heterocyclic amines (HAs), the relationship between polymorphisms of enzymes involved in PAH and HA metabolism and the occurrence of sporadic colorectal cancer was studied.
Patients and methods: Five hundred colorectal cancer patients and 500 controls were genotyped for cytochrome P450 enzymes (CYP) 1A1 Ile/Val, CYP 1A2*1F, CYP 2E1 c1/c2, microsomal epoxy hydrolase (mEH) exon 3 Tyr113His and exon 4 His139Arg polymorphisms by allele-specific polymerase chain reaction (PCR) or PCR-restriction fragment length polymorphism (RFLP).
Results: The presence of CYP 1A1 Val, CYP 2E1 c2 and mEH exon 3 His alleles was statistically significantly associated with the occurrence of colorectal cancer (OR: 1.44 95% CI: 1.04-2.00; OR: 1.74 95% CI: 1.15-2.65; OR: 1.79 95% CI: 1.10-2.92, respectively).
Conclusion: These findings suggest that allelic polymorphism of metabolizing enzymes play an important role in human colorectal carcinogenesis by affecting the metabolism of dietary carcinogens.