CDK6 and breast cancer: These results are similar to the effects of RNAi knockdown of other genes involved in cell cycle progression, such as livin in human osteosarcoma cells [33], cyclin-dependent kinase 6 in medulloblastoma cells [34], Bmi-1 in laryngeal carcinoma cells [35], NANOG in breast cancer cells [36], and EZH2 in colon cancer cells [37].