CDK4 and hepatocellular carcinoma: Consistently, the key regulatory factors of cell cycle progression10, including cyclinB1, cyclinD1, and CDK4 were significantly decreased, while the negative regulators of cell cycle progression, including CDKN1A (P21) and CDKN1B (P27) increased in HCC-LM3/AC and HepG2/AC cells compared with the controls (Fig. 2e, f).