CDK4 and acute myeloid leukemia: To evaluate the anti-leukemia effects of CDK4/6i and/or ATRA, drug administration began 14 days post-transplantation of primary AML cells derived from mice, coinciding with the emergence of GFP+ (MLL-AF9+) cells in the peripheral blood (PB) of the recipients, as outlined in the schedule (Fig. 6c).