METTL3 and hepatocellular carcinoma: The methyltransferases methyltransferase-like 3 (METTL3) and methyltransferase-like 14 (METTL14), which are major responsible proteins for m6A-RNA-methylation, were found to be upregulated in HCC in several studies leading to increased tumor growth both in vitro and in vivo [264].