Additionally, treatment of HCC cells with 3-deazaadenosine (DAA), which inhibits SAH hydrolase and interrupts insertion of m6A into mRNA substrates33,34, significantly decreased total m6A in PLC-8024 and Huh7 cells (Supplementary Fig. 6h) and the expression of HEG1 mRNA and protein in the parental and Huh7-R HCC cells (Fig. 5r; Supplementary Fig. 6i, j), suggesting that m6A is critical for the stability of HEG1 mRNA. Here, HEG1 is linked to hepatocellular carcinoma.