NPM1 and acute myeloid leukemia: Of interest, the immunohistochemical staining, retrospectively performed on BM trephine biopsies even from these two deceased subjects, documented diffuse NPMc+ staining in >20% BM cells with multilineage involvement, therefore suggesting that NPMc+ AML, rather than MDS, could have been presumptively diagnosed, ab initio, in both these cases by the combination of NPM1 molecular and immunohistochemical investigations [69].