HCC is characterized by the low expression of the liver-specific MAT1A gene that encodes the MATI/III isozymes; and the high expression of MAT2A that encodes the MATII isozyme, as well as high expression of MAT2B that encodes a β-subunit without catalytic action but can regulate MATII enzymatic activity [23]. The gene discussed is MAT1A; the disease is hepatocellular carcinoma.