Megakaryocytes expansion in BM biopsy of NPM1-mutated AML patients. (A-B) Representative BM sections from a nonleukemic control were stained with (A) hematoxylin and eosin and (B) an anti-LAT antibody. (C-D) BM trephine sections from an NPM1-mutated AML patient with an increased number of megakaryocytes (∼20 megakaryocytes ×40 field) as assessed by (C) hematoxylin and eosin and (D) immunostaining for human LAT. (E) Nucleus-restricted NPM1 expression in a representative NPM1-unmutated AML patient. (F) Aberrant cytoplasmic expression of NPM1 in dysplastic megakaryocytes (original magnification, ×40) of an NPM1-mutated AML patient. (G) LAT positive megakaryocytes in a representative NPM1-mutated AML patient with a megakaryocytes concentration >40 per ×40 field (original magnification, ×40).