Wong et al. showed that global H3K4me3 levels are higher in leukemia stem cells (LSCs) than in differentiated leukemia cells in MLL-rearranged AML, as well as that the expression of LSC maintenance genes is reduced in association with decreased H3K4me3 levels and LSC differentiation [130]. The gene discussed is KMT2A; the disease is acute myeloid leukemia.