We first assessed the effect of MPA on several human AML cell lines (with MLL‐fusions: MV4;11, MOLM13, NOMO1 and THP1, without MLL‐fusions: HL60, Kasumi‐1, OCI‐AML3 and U937), human cord blood (CB) CD34+ cells, and those expressing MLL‐AF9 (CB‐MA9#1, 2, 3) or MLL‐ENL (CB‐MLL‐ENL#1, 2), and patient‐derived xenograft (PDX) cell lines derived from AML patients with or without MLL‐fusions (AML#1, 2, 3 or AML#4, 5, 6, Appendix Table S1). The gene discussed is KMT2A; the disease is acute myeloid leukemia.