Cytoplasmic nucleophosmin (cNPM) in acute myeloid leukaemia: Relation to disease characteristics

osting by E Abstract Background: Nucleophosmin/B23 (NPM) is a 38 kDa molecular phosphoprotein involved in ribosome assembly and transport. Findings have revealed a complex scenario of NPM functions and interactions, pointing to proliferative and growth-suppressive roles. NPM appears to be more abundant in tumour cells than in normal cells. Objective: The aim of the work was to identify cytoplasmic localization of NPM using bone marrow clot biopsy and correlate it with disease and patient characteristics and the known prognostic factors, induction chemotherapy response and survival after 12 months of follow up. Methods: The present work was undertaken on 50 cases of normal karyotype acute myeloid leukaemia classified according to modified FAB system. Bone marrow aspirates were obtained, clotted and a formalin-fixed, paraffin embedded cell block was prepared. Sections were immunostained for NPM. Results: Twenty-six cases (52%) had cytoplasmic positivity (cNPM+) while the remaining 24 cases (48%) had nuclear restricted NPM (cNPM ). cNPM positivity was significantly variable among the different FAB subtypes being the most prevalent among M5 and M2 cases, was associated with high blast and white blood cell count at diagnosis. It was significantly correlated with CD34