CDK4 and neoplasm: Simultaneous blockade of cell cycle progression in G1 and G2/M phase using CDK4/6 and AURKA inhibitors showed synergistic interaction only in AMBRA1 responder cells with an AMBRA1 knockout (Fig. 8C), further suggesting that tumor cells in which AMBRA1 fulfills a tumor suppressive role might be particularly sensitive to AURKA inhibition.