Two of the most investigated polymorphisms of MTHFR, rs1801133 (Ala222Val, 677C>T) and rs1801131 (Glu429Ala, 1298A>C), have been proved to have close association with the onset of some cancers, including colorectal cancer [30] and breast cancer [31]. This evidence concerns the gene MTHFR and colorectal cancer.