PRDM9 and hepatocellular carcinoma: The HBx protein can also induce histone methylation transferases and it has been demonstrated that HBx induced upregulation of SMYD3, that encodes for histone H3-K4-specific methyltransferase (HMT), is linked to the upregulation of the oncogene C-MYC in HCC (138, 139) (Figure 1E).