Frequency of Nucleophosmin 1 Expression by Immunohistochemistry in Acute Myeloid Leukemia.

Nucleophosmin (NPM1) mutation is one of the most common recurring genetic abnormalities seen in acute myeloid leukemia (AML). Immunohistochemistry serves as a cost effective and simple surrogate testing method for detection of NPM1 mutation. This study was conducted to evaluate the frequency of aberrant cytoplasmic nucleophosmin 1 expression in leukemic blast cells on formalin fixed bone marrow trephine biopsy (BMB) sections and also to correlate this data with the reference molecular method (reverse transcriptase-polymerase chain reaction; RT-PCR and gene sequencing), where available.