Multilineage dysplasia does not influence prognosis in CEBPA-mutated AML, supporting the WHO proposal to classify these patients as a unique entity.

In 2008, the World Health Organization introduced CEBPA (encoding the CCAAT/enhancer binding protein)-mutated acute myeloid leukemia (AML) as a provisional entity. However, the classification of CEBPA-mutated AML with multilineage dysplasia (MLD; ≥ 50% dysplastic cells in 2-3 lineages) remains to be clarified. In the present study, we investigated 108 CEBPA-mutated AML patients for the impact of MLD, karyotype, and additional mutations. MLD(+) patients differed from MLD(-) patients only by lower mean WBC counts, not by biologic characteristics, cytogenetic risk profiles, or additional mutations. Survival was better for female patients, patients < 60 years of age, for intermediate versus adverse karyotypes, and, in the case of FLT3-ITD negativity, biallelic versus monoallelic/homozygous CEBPA mutations. In contrast, 2-year overall survival and event-free survival did not differ significantly between MLD(+) and MLD(-) patients. By univariable Cox regression analysis, sex, age, WBC count, and cytogenetic risk category were related to overall survival, but MLD was not. Therefore, because dysplasia is not relevant for this subtype, CEBPA-mutated AML patients should be characterized only according to mutation status, cytogenetic risk group, or additional mutations.