Lower frequency of NPM1 and FLT3-ITD mutations in a South African adult de novo AML cohort

Abstract

Introduction: Acute myeloid leukemia (AML) is a heterogeneous clonal disorder of hemopoietic progenitor cells diagnosed in individuals of any age, but with a median age of 67 years at presentation in adults. Assessment of the mutation status of nucleophosmin protein-1 (NPM1) and FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) is essential for the prognosis, and treatment of AML. Methods: A total of 160 de novo AML cases, both cytogenetically normal and abnormal, were analyzed for the presence of NPM1 and FLT3-ITD mutations, and the results assessed in conjunction with epidemiological, clinical, and laboratory findings. Results: Nucleophosmin protein-1 mutations were found in 7.5%, while FLT3-ITD was present in 12% of these cases. Both of these were lower than expected. The median age at diagnosis of AML was 41 years, and for the FLT3-ITD only cases, median age was 33 years; these ages were younger than expected. Conclusion: The lower reported frequencies and younger median age at diagnosis of AML and these specific mutations may be contributed to by a number of factors including effects of race on age of presentation, inclusion of patients diagnosed with de novo AML only, and a generally younger median age of the South African population.