CDKN1B and hepatocellular carcinoma: In addition, the combination therapy has been shown to impair HCC growth by delaying the cell cycle and inducing apoptosis, since IFN-α/5-FU-treated human HCC cell lines show cell accumulation in the G0/G1 phase and increased expression of the cell cycle-related protein p27Kip1 (Eguchi et al, 2000).