TP53 and hepatocellular carcinoma: Additionally, p53 knockdown increased HBx levels in HBV-infected HepG2-NTCP cells, whereas p53 expression decreased HBx levels in HBV-infected Hep3B-NTCP cells (Figure 3E,F), confirming the role of p53 as a negative regulator of HBV replication in human hepatoma cells.