CDK4 and acute myeloid leukemia: Enhanced efficacy with dual pan-Pim kinase inhibitors and CDK4/6 (PD 0332991), JAK/STAT5 (ruxolitinib) inhibitors, or CXCR4 antagonists (BL-8040 and Plerixafor) that are in clinical trials, may also prove beneficial in treating refractory AML [154–159].