NPM1 and myelodysplastic syndrome: As mentioned above, in the seminal study by Falini et al., NPMc+ was documented by immunohistochemical examination in 208 of 591 (35.2%) BM trephine biopsy specimens obtained from patients with de novo AML, whereas normal nuclear NPM1 protein localization was found in 135 secondary AML (sAML) specimens and in 980 hematopoietic or extra-hematopoietic neoplasms other than AML, including acute lymphoblastic leukemia, chronic myeloid leukemia, non-Hodgkin lymphoma and myelodysplastic syndrome (MDS) cases [12].