CDK4 and acute myeloid leukemia: In this study, we find that VEGF receptor tyrosine kinase Flk-1 and CDK4/cyclin D1 enzyme inhibitor, Ox-1 (Figure 1A; Figure S1A), minimally inhibits cell growth in AML cell lines (Figure 1B), and minimally induces cell apoptosis by cell cycle distribution, and in fact generates resistant polyploid cells in a dose- and time-dependent manner (Figure 1C–1F).