Once a NPM1 mutation has been recognized, the definitive diagnosis of NPM1-mutated AML requires that other distinct and provisional AML entities of the 2017 WHO classification, such as AML-MRC (case 2), AML with BCR-ABL1 (case 6, Fig. 6) and AML with RUNX1 mutations (Fig. 6) are excluded. This evidence concerns the gene ABL1 and acute myeloid leukemia.