CDK4 and neoplasm: In vivo, AT7519 effectively inhibited the AM tumor growth bearing CDK4 gain + CCND1 gain, CDK4 gain + p16INK4A loss or only CDK4 gain, whereas palbociclib was effective in mouse models with CDK4 gain + CCND1 gain and CDK4 gain + p16INK4A loss (Table 1, Figure 4).