Evaluation of Morphological, Clinical, and Prognostic Significance of Nucleophosmin Gene Mutation in de novo Acute Myeloid Leukemia

Introduction: Nucleophosmin 1 (NPM1) is a molecular chaperone protein. Mutation of NPM1 gene is identified to be one of the most predominant molecular abnormalities in acute myeloid leukemia (AML). Among the genetic mutations, NPM1 along with FMS-like tyrosine kinase 3 (FLT3) mutations lead to poor prognosis and unfavorable outcomes in patients with AML. Methods: This was a retrospective study conducted for 2 years at a leading cancer care center in India. A total of 10 patients were identified to be NPM1 positive in 50 identified AML patients. Results: In 10 NPM1-positive patients, eight patients were female. All were adults with a median age of 39.3 years. The majority of the patients were presented with Auer rod (7/10) and intranuclear cup-like inclusions (7/10) with increased number of blasts in peripheral blood smear (77.88%). Lymphadenopathy was absent in all patients. Morphological analysis has shown blast cells with a cup shape and prominent nucleoli with indentation. Whereas, immunophenotyping analysis has shown lower positivity of cluster of differentiation 34 (12%) and lack of human leukocyte antigen-DR expression (34%). Conclusion: The presence of NPM1 mutations alone without FLT3 mutations in patients with AML was observed to have a better prognosis of the disease. Early identification of such mutations by morphological and immunophenotyping analysis can play a vital role in treatment initiation at the earliest for better prognosis and clinical outcomes without much delay.