VMY-1-103 is a potent CDK inhibitor, is also a novel dansylated analog of purvalanol B, was shown to inhibit cell cycle progression and proliferation in prostate and breast cancer cells more effectively than purvalanol B. VMY-1-103 , but not purvalanol B, significantly decreased the proportion of cells in S phase and increased the proportion of cells in G(2)/M. VMY-1-103 increased the sub G(1) fraction of apoptotic cells, induced PARP and caspase-3 cleavage and increased the levels of the Death Receptors DR4 and DR5, Bax and Bad while decreasing the number of viable cells, all supporting apoptosis as a mechanism of cell death. VMY-1-103 possesses unique antiproliferative capabilities and that this compound may form the basis of a new candidate drug to treat medulloblastoma.