NPM1 and acute myeloid leukemia: AML with mutated NPM1 may be further stratified into two different categories: those patients where concomitant FLT3-ITD (FMS-like tyrosine kinase internal tandem duplication) is absent, usually respond to standard induction therapy and have favourable prognosis; when FLT3-ITD sums up to NPM1 mutations (around 30% of cases) the prognosis is much worse.