CDK4 and cancer: Where, most newly synthesized compounds might be considered as potent anticancer candidates for their ability to enhance the expression level of apoptotic genes (P53, BAX, DR4, DR5, and caspase-3), lower the expression of anti-apoptotic genes (CDK4, Bcl2, and Il-8), arrest the cell cycle at G1/S phase, induce apoptosis and cause DNA fragmentation in the selected cancer cell lines.