Red meat intake, CYP2E1 and PPARγ polymorphisms, and colorectal cancer risk

The association between red meat intake and colorectal cancer (CRC) may be modulated by genetic polymorphisms of cytochrome P450 2E1 (CYP2E1), a key enzyme in the metabolism of nitrosamines, and peroxisome proliferator-activated receptor gamma (PPARγ), a transcription factor involved in adipogenesis and lipid and glucose metabolism. We conducted a case-control study of 971 patients with CRC and 658 controls who were admitted to two university hospitals between 1995 and 2004 in Seoul, Korea. Participants were asked about red meat intake by using a validated food frequency questionnaire. Polymorphisms of CYP2E1 (rs3813867) and PPARγ (rs1801282 or rs3856806) were identified using the TaqMan assay. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using multivariable logistic regression models. We found that the association between red meat and CRC varied by CYP2E1 polymorphisms; ORs (95% CIs) for at least five or more vs. less than one time/week of red meat intake were 2.77 (1.23-6.25) among individuals with C alleles of CYP2E1 and 0.89 (0.51-1.54) among individuals with the GG allele (Pinteraction=0.05). Compared with those individuals with the CC allele, increasing risk of CRC with increasing red meat intake was more pronounced among individuals with T alleles of PPARγC161T (rs3856806), but the association was not significant. Our data provide evidence that East Asians with the variant type of CYP2E1 may have high susceptibility to development of CRC risk.