ASXL1 mutations are infrequent in young patients with primary acute myeloid leukemia and their detection has a limited role in therapeutic risk stratification.

ASXL1 mutations are recurrent in acute myeloid leukemia (AML), but it is unclear whether ASXL1 genotype might influence patient management. We analyzed frequency and impact in younger (15-59 years) and older (≥ 60 years) patients with primary or secondary disease. Overall, 9% had truncating mutations. Incidence was significantly lower in younger patients with primary than with secondary disease (4%, 12%; p = 0.03). In older patients it did not differ significantly (11%, 15%; p = 0.5). In univariate analysis, ASXL1-mutated patients had a worse outcome (5-year relapse 83% vs. 56%, p = 0.01; overall survival [OS] 6% vs. 22%, p = 0.02). However in multivariate analysis, ASXL1 mutations had no prognostic significance (for OS, p = 0.3), because age was a major confounding factor. The low incidence of mutations in younger patients with primary disease and the lack of significance in multivariate analysis indicate that there is a limited role for screening at diagnosis for ASXL1 mutations for the purpose of prognostic stratification.