Schematic representation of regulation of granulopoiesis and AML by C/EBPα–miR-34a-E2F3 axis. During granulopoiesis (top panel), C/EBPα transactivates miR-34a, which, in turn, leads to E2F3 repression and inhibition of cell-cycle progression, resulting in myeloid differentiation. During CEBPA mutations in AML (bottom panel), low activity of C/EBPα fails to transactivate miR-34a, which results in lack of E2F3 inhibition. Overexpressed E2F3, together with E2F1, could accelerate myeloid cell-cycle progression and results in block of granulocytic differentiation.