DHFR and cancer: There was a general trend that the cancer group had increased polymorphisms and lesser percentage of wild type alleles for all genes including MTHFR C677T, MTR A2756G, MTRR A66G, and DHFR 19bp, except for MTHFR A1298C, where the control group had increased polymorphisms and lower wild type alleles compared to the CRC group, which had decreased polymorphisms and higher wild type alleles.