Our analysis of histone acetylation patterns in IRX3high primary AML samples shows that around half of cases exhibit strong H3K27ac ChIP signal across a ∼32kB region within intron 8 of FTO. By comparison with IRX3high primary AML cases which lack strong intron 8 FTO acetylation, intron 8 acetylated cases are less well differentiated based on their gene expression profile, and express higher levels of stem cell genes such as HOXA9, GATA2, and SOX4, even while they do not differ significantly from a mutational viewpoint. The gene discussed is FTO; the disease is acute myeloid leukemia.