Monocytopoiesis is largely controlled by a unique combination of lineage-specific transcription factors, including vitamin D receptor (VDR), acute myeloid leukemia-1 (AML1) and CCAAT/enhanced-binding protein β (C/EBPβ), which cooperatively regulate promoters or enhancers present on their target gene.7 We evaluated whether the impaired D3-induced monocytic differentiation in the absence of Ago2 resides on the deregulation of the above-mentioned transcription factors. This evidence concerns the gene CEBPB and myeloid leukemia.