Euchromatic histone lysine methyltransferase 2 (G9a, EHMT2) and suppressor of variegation 3-9 homolog 1 (SUV39H1) are mainly involved in the methylation of histone H3K9 to induce the formation of heterochromatin, and G9a upregulation was significantly associated with malignant clinicopathological features of HCC [158]. Here, SUV39H1 is linked to hepatocellular carcinoma.