IRX3 and acute myeloid leukemia: One candidate is the Iroquois homeobox transcription factor gene IRX3, which, like FOXC1, is expressed in a significant proportion of patients with AML (Somerville et al., 2015) but minimally expressed in both normal hematopoietic stem and progenitor cells (HSPCs) and mature blood cells (ENCODE data; Zhou et al., 2011).