Acute Myeloid Leukemia: Correlation of NPM1 Mutation with Morphology and Immunophenotypic Findings

Abstract

BACKGROUND: NPM1 mutation is the most commonly mutated leukemic entity in acute myeloid leukemia (AML) and usually poses a favourable prognosis. It is important to find an association of this mutation with clinical presentation, different hematological parameters and immunohistochemistry to assist the pathologists with stratification of AML cases having different prognostic subgroups in low resource settings where molecular analysis is not easily available for NPM1 detection.

OBJECTIVE: to correlate NPM1 mutation in acute myeloid leukemia with specific morphology and immunophenotyping in Pakistani population.

Material and methods: Clinical history with peripheral blood and bone marrow aspirate samples were collected from 50 newly diagnosed cases of AML at Chughtai Institute of pathology from June 2022 to April 2024 after taking informed consent. NPM1 mutation was detected using Imegen-NPM1 kit via Reverse Transcriptase-Polymerase Chain Reaction (PCR).

Statistical Analysis: Normality of data was assessed using Kolmogrov Smimov test. Comparison was made using Chi-square test.

 Results: NPM1 mutation was detected in 20% of the AML cases affecting mainly female population of age 40 years and above. Relatively high TLC count, M4 FAB type morphology and low CD34 expression (p<0.05) was observed in NPM1 mutated cases. 1 year remission was seen in 60% of the cases diagnosed with NPM1 suggesting a significant correlation between NPM1 mutation and remission (p<0.05).

Conclusion: NPM1 mutation is less common in our society and mainly correlates with female gender, old age,  certain hematologic and immunhistochemical markers as well as with better overall remission.  

Key Words: Acute myeloid leukemia (AML), Nucleophosmin1 (NPM1) gene, Hematologic and immunophenotypic parameters.