MAT1A and hepatocellular carcinoma: MATII consists of α2 catalytic subunit encoded by MAT2A and β regulatory subunit encoded by MAT2B. Hepatocellular carcinoma (HCC) is characterized by the low expression of the liver-specific MAT1A gene that encodes the SAM synthesizing isozymes MATI/III; and the high expression of the widely MAT2A that encodes the MATII isozyme and high expression of MAT2B that encodes a β-subunit without catalytic action, but it can regulate MATII enzymatic activity [15].