Furthermore, two MDS/MPN cases that underwent progression (case 19 into AML/myelosarcoma; case 17 in form of increased peripheral blasts) developed mutations typically found in primary AML and rather unusual for AML secondary to MDS/MPN (NPM1 in case 19; FLT3-ITD in case 17). This evidence concerns the gene NPM1 and myeloproliferative neoplasm.