CCND1 and plasma cell myeloma: ➢Is a CDK1, 4 and 9 inhibitor with IC50 of 79 nM, 63 nM and 20 nM, respectively. ➢Shows antiproliferative effects against various human cancer cell lines, down-regulates cyclin D1 and CDK4 in an ATP-competitive manner and decreases CDK4-specific retinoblastoma protein phosphorylation, induces apoptosis by activating cellular caspase-3 activity and DNA ladder formation.➢Induces apoptosis that correlates with transcription inhibition and a significant decline in Mcl-1 protein levels with the appearance of cleaved PARP in myeloma cells. In vivo studies confirmed its antitumor activity.