Aim: To evaluate the contribution of methyl-enetetrahydrofolate reductase (MTHFR) genotype to the risk of colorectal cancer (CRC) in Taiwan. Materials and Methods: In this hospital-based case-control study, the role of MTHFR C677T (rs1801133) and A1298C (rs1801131) genotypes in determining CRC risk were investigated among 362 patients with CRC and an equal number of age-and gender-matched healthy individuals. Results: The percentages of CC, CT and TT genotypes for MTHFR rs1801133 were 64.1%, 29.8% and 6.1% in the CRC group and 51.1%, 37.0% and 11.9% in the control group, respectively (p for trend=0.0006). Analysis of the allelic frequency distribution showed that the variant T allele of MTHFR rs1801133 conferred a lower CRC susceptibility than did the wild-type C allele (odds ratio(OR)=0.66, 95% confidence interval(CI)=0.52-0.84, p=4.32x10-5). For the gene-lifestyle interaction, there were obvious protective effects of MTHFR rs1801133 T allele on the risk of CRC among non-smokers, ever smokers and non-alcohol drinkers, but not drinkers. Conclusion: MTHFR rs1801133 T allele serves as a predictive marker for CRC risk and future studies with larger samples and functional evaluation are warranted to validate the current findings.
