Association between Genetic Polymorphism of Methylenetetrahydrofolate Reductase with Non Familial Colorectal Cancer in Iranian Population

Methylenetetrahydrofolate reductase (mthfr) is a key enzyme regulating folatemetabolism, which affects dna methylation and synthesis. one of the most importantpolymorphisms identified in the mthfr gene is c677t. mthfr activity is lowered inindividuals with 677tt genotype.using pyrosequencing, we analyzed the mthfr genotypes in 118 colorectal cancerpatients and 189 normal matched controls. whereas the cc, ct and tt genotypesof mthfr among the colorectal cancer patients were 51.7%, 28.0 % and 20.3%respectively, we were able to find 47.1% of 677cc, 27.0% of 677ct and 25.9%of 677tt in normal controls. an inverse association was observed between the riskof colorectal cancer and tt genotype with the odds ratios (or) of 1, 0.94 and 0.71for cc, ct, and tt genotypes, respectively. this association was similar in bothsexes, but in patients with high levels of folate intake. our study corroboratesprevious findings of an inverse association between mthfr 677tt genotype andcolorectal cancer, especially at high levels of folate.