Because of this, it can be hypothesized that purine analogs used in AML, like fludarabine and cladribine, could have a different effect on AML based on the mutational status of TET2/IDH1/2/WT1 and NPM1 and on the expression level of RUNX1. There is an important possibility that this is the case, as NPM1 is known to offer a good prognosis in AML [26]. This evidence concerns the gene NPM1 and acute myeloid leukemia.