Diagnostic criteria were largely unchanged in the new proposal except for these: (1) persons with KMT2A, MECOM, NUP98 rearrangements and NPM1 mutation are classified as acute myeloid leukaemia (AML) regardless of percentage blasts; and (2) diagnosis of MDS unclassifiable (MDS-U) was eliminated and partly replaced by clonal cytopenia of undetermined significance (CCUS). This evidence concerns the gene MECOM and acute myeloid leukemia.