Main characteristics of NPM1-mutated AML
| Specific characteristics and comments . |
|---|
| Approximately 30-35% of adult AML (50-60% of AML with normal cytogenetic). Less frequent in children (∼2-8%).* Female predominance. |
| BM usually markedly hypercellular. Mostly myelomonocytic (FAB M4) and monocytic (FAB M5), but all FAB categories are represented. |
| Approximately 23% of cases show multilineage dysplasia. |
| WBC count may be influenced by FLT3 mutational status, progressively increasing from FLT3 wild-type to FLT3-ITDhigh. |
| Frequent association with extramedullary involvement, especially skin (easily detectable by IHC). |
| No/low expression of CD34. The rare CD34+ leukemic cells carry the NPM1 mutation. CD34 positivity has been associated with adverse prognosis. |
| Excellent response to induction chemotherapy. |
| Relatively good outcome in the absence of FLT3-ITD. Prognosis may vary depending upon concomitant mutations. |
| Specific characteristics and comments . |
|---|
| Approximately 30-35% of adult AML (50-60% of AML with normal cytogenetic). Less frequent in children (∼2-8%).* Female predominance. |
| BM usually markedly hypercellular. Mostly myelomonocytic (FAB M4) and monocytic (FAB M5), but all FAB categories are represented. |
| Approximately 23% of cases show multilineage dysplasia. |
| WBC count may be influenced by FLT3 mutational status, progressively increasing from FLT3 wild-type to FLT3-ITDhigh. |
| Frequent association with extramedullary involvement, especially skin (easily detectable by IHC). |
| No/low expression of CD34. The rare CD34+ leukemic cells carry the NPM1 mutation. CD34 positivity has been associated with adverse prognosis. |
| Excellent response to induction chemotherapy. |
| Relatively good outcome in the absence of FLT3-ITD. Prognosis may vary depending upon concomitant mutations. |
A synonym of NPM1-mutated AML is “AML with cytoplasmic nucleophosmin” (NPM1c+).
FAB, French-American-British.
Likely because NPM1 mutations are often preceded by clonal hematopoiesis, which is very rare in children.