Therapy-related acute myeloid leukemia (t-AML) is described in the WHO classification [1–2] as AML occurring after a previous cancer whose treatment comprises mainly an alkylating agent, ionizing radiation therapy – giving rise to chromosome 5 or 7 abnormalities, and/or topoisomerase II inhibitor – generating balanced translocations, including t(15;17) [3] or 11q23 [MLL] rearrangements among others. The gene discussed is KMT2A; the disease is acute myeloid leukemia.