The presence of NPM1 mutations in AML has prognostic significance which is modified with co-mutations in FLT3 (internal tandem duplications, ITD) and DNMT3A. For example, NPM1 mutation without FLT3 ITD or DNMT3A co-mutation tends to be associated with a better prognosis, than when co-existing with FLT3 ITD and/or DNMT3A mutations (2, 5–8). This evidence concerns the gene DNMT3A and acute myeloid leukemia.