While we cannot exclude an effect of azacitidine on the leukemia response in humans, these results suggest that an HDAC epigenetic-based therapy limits Myc pathways in 3q26 AML and that azacitidine-based protocols may not be as effective in 3q26 AML as they are in other AML subgroups. This evidence concerns the gene HDAC9 and acute myeloid leukemia.