Prevalence, clinical profile, and prognosis of NPM mutations in AML with normal karyotype

Mutation of the nucleophosmin (NPM) gene has been reported as the most frequent mutation in acute myeloid leukemia (AML), especially in the presence of a normal karyotype. In this subgroup of intermediate-risk AML, the identification of other gene mutations (eg, FLT3, CCAAT/enhancer-binding protein-alpha CEBPA) has helped to refine the prognosis. This study explored the prevalence and the prognostic impact of NPM mutations in a cohort of 106 patients with normal-karyotype AML. NPM exon 12 mutations were detected by polymerase chain reaction (PCR) and fragment analysis for the insertion/deletion globally resulting in a 4-bp insertion. NPM mutations were detected in 47% of patients and were associated with a high white blood cell count, involvement of the monocytic lineage (M4/M5), and a decreased prevalence of CEBPA mutations. Complete remission rate and long-term outcome did not differ between NPM-mutated and -nonmutated patients. Prospective studies are needed to confirm the definitive place of NPM mutation detection to predict AML response to therapy.