TP53 and hepatocellular carcinoma: Ginsenoside Rs4 induces apoptosis, the effect of which is closely related to the downregulation of both cyclin E- and A-dependent kinase activity as a consequence of selectively elevating the protein levels of p53 and cyclin-dependent kinase inhibitor 1 (p21WAF1) in hepatoma SK-HEP-1 cells [88].