Primary blast samples from patients harboring a MLL rearrangement (MLLr), FLT3-internal tandem duplication positive (FLT3-ITD+), or with acute megakaryoblastic leukemia (AMKL) were plated on mesenchymal stromal cells and treated with DMSO or increasing concentrations of indicated compounds. The gene discussed is KMT2A; the disease is acute megakaryoblastic leukemia.