CDKN2A and hepatocellular carcinoma: With the induction of CDKN2A expression by sgiACTR5, immunoblotting revealed a drastic reduction of CDK6, phospho-S780 Rb (p-Rb), and E2F1 protein level in the ACTR5-dependent HCC cells (Fig. 3A; HepG2 and SNU475).