CDK4 and neoplasm: CyclinD, CDK4, or CDK6 gene ablation could be reduced to prevent tumor formation.[61] Many studies have demonstrated that regulating the cell cycle may be a therapeutic strategy in tumors, and related drugs targeting CDK4 or CDK6 have been developed, such as Palbociclib and Ribociclib.[62,63] As compared to the previous chemotherapy drugs, the side effects of these are much less severe.