Methylene tetrahydrofolate reductase (encoded by MTHFR) is a key enzyme in metabolism of folate and nucleotides to maintain DNA stability and prevent cancers through catalysing irreversible conversion of 5,10-methylenetetrahydrofolate (5, 10-methyleneTHF) to 5-methyl tetrahydrofolate (5-methyl THF) [24, 25, 26]. This evidence concerns the gene MTHFR and cancer.