Molecular and alternative methods for diagnosis of NPM1-mutated AML. AML with mutated NPM1 can be diagnosed either by mutational analysis or by alternative methods based on detection of aberrant cytoplasmic expression of nucleophosmin (immunohistochemistry on tissue sections or flow cytometry) or the mutant NPM1 protein with specific antibodies (Western blotting). The 2 approaches are complementary (bidirectional arrows). Evaluation of the FLT3 status should be carried out in all NPM1-mutated AML patients because it is instrumental to identify the subgroup of cases with NPM1-mutated/FLT3-ITD-negative genotype that has a more favorable prognosis. Primers can be designed that allow monitoring of minimal residual disease (MRD).