NPM1 and acute myeloid leukemia: Thus, due to the known limitations of the retrospective nature, the small sample size and the lack of evaluation of co-existing mutations of the conducted study [65], larger prospective trials incorporating different age subgroups and various applied treatments, along with the presence of concomitant mutations, are necessary to assess the effects of possible allogeneic HSCT in NPM1-positive, FAB M4 and M5 AML patients.