CCNB1 and hepatocellular carcinoma: Moreover, its knockdown in human lung cancer cells, hepatocellular carcinoma (HCC) and colon cancer cells inhibited the expression of several key proteins associated with the G2/M phase, such as, cyclin B1, CDC2 and CDC25C, while upregulating p21, p27 and PLK1 (21, 23, 24).