Multiple retained introns (n=14) were identified in the 5 primary and PDX AML samples in the following genes: ZCCHC7, ABL1, JAK2, IRF8, TAL1, CEBPG, ETV6, KMT2A, MLLT10, KLF2, and PRDM16 (Supplementary Table 2). The gene discussed is KMT2A; the disease is acute myeloid leukemia.