Objective: Molecular genetic analysis of FLT3, NPM1, and CEBPA is already the standard of care in patients with acute myeloid leukaemia (AML) and represents the most frequent genetic alterations and important diagnostic and prognostic indicators. This study was undertaken to determine the frequency of FLT3 and NPM1 gene mutations in our institution and to characterize the association between gene mutations and haematological parameters as well as immunophenotypic features.

Material and Method: Morphological, haematological and immunophenotypic characteristics of NPM1 and FLT3 mutations in 126 patients of de novo AML including adults and children were studied. Apart from the French American British (FAB) method for classification, blasts were assessed for cuplike morphology as per strict definition for cuplike nuclei, ≥10% blasts with nuclear invaginations ≥25% of the nuclear area.

Results: FLT3 mutation in 31/126 (25%) and NPM1 mutation was found in 17/126 (13.4%) of the AML patients. 6 (5%) samples were positive for both NPM1 and FLT3/ITD mutations. Associations between the FLT3 and NPM1 gene mutations with haematological and immunophenotypic characteristics are reported.

Conclusion: The results suggest that presence of distinct morphology and haematological and immunophenotypic characteristics together may serve as important indicators and surrogate for NPM1 and FLT3/ITD mutations. Further, comprehensive studies on the biological effects of NPM1 and FLT3/ITD mutations and their interactions with other genetic alterations are needed to gain insight into the molecular mechanism of these mutations involved in the pathogenesis of AML.