Most importantly, the study by Yu MC et al.[75] indicated that low-activity genotypes (reduced enzymatic activities) of MTHFR and high-activity genotypes (enhanced enzymatic activities) of thymidylate synthase (TYMS), both of which discourage the misincorporation of uracil into DNA, are associated with a reduced risk of HCC. Here, MTHFR is linked to hepatocellular carcinoma.