The 677C > T mutation in 5,10-methylenetetrahydrofolate reductase and colorectal cancer risk.

This paper examines whether there is a relationship between a common mutation in the methylenetetrahydrofolate reductase gene, MTHFRval, and the risk of colorectal cancer, with or without lymph node metastases. MTHFR genotypes were ascertained from peripheral leukocyte samples obtained from 200 colorectal patients, including TMN stages I-VI, and from 460 healthy, unrelated adults without colorectal cancer, who served as controls. The frequency of homozygosity for the MTHFRval/val genotype among the colorectal cancer patients was lower (14.0%) than among controls (16.1%). The latter finding results in an estimated MTHFRval allele frequency of 0.41. The MTHFRval allele (677C > T) reduces colorectal risk slightly [odds ratio (OR), 0.87]. However, there was a significantly higher incidence of metastatic lymph nodes per case in MTHFRval/val patients, when compared with MTHFRala/*ala controls (6.9 +/- 1.55 vs. 3.7 +/- 0.57, p = 0.003). These results suggest that the MTHFR genotype might be of prognostic significance in colorectal carcinoma.