Vibsanin A promoted monocytic differentiation in HL-60 cells, megakaryocytic differentiation in CML cells, and induced differentiation in 10 of 11 primary AML samples in a concentration-dependent manner (maximum 10 μM). In mouse xenograft models, it extended host survival, effects mediated via protein kinase C activation and the Raf/MEK/ERK signaling pathway. This evidence concerns the gene RAF1 and chronic myelogenous leukemia, BCR-ABL1 positive.