In general, the spectrum of co-mutations of patients with bZIPInDel mutations differed markedly from the other CEBPA subgroups, the latter more frequently carrying mutations in genes associated with AML after prior MDS, such as spliceosome mutations (i.e. SRSF2, SF3B1, U2AF1 or ZRSR2) as well as alterations associated with DNA-methylation (i.e. DNMT3A, TET2, IDH1 and IDH2) (Fig. 4, Table S3). The gene discussed is U2AF1; the disease is acute myeloid leukemia.