HDAC9 and hepatocellular carcinoma: For example, the HBx protein can promote HAT by recruiting trans-activator proteins like CBP/p300 complex to induce H3K9ac (135) Conversely, the HBx protein can induce HDAC to promote cell proliferation in HBV-HCC by repressing tumor suppressors like p21/p27 that are important regulators of cell cycle control (132) (see Figure 1F) and promote epithelial-mesenchymal transition (EMT) by repressing CDH1 (137).