AML typical mutations (CEBPA, FLT3, and NPM1) identify a high-risk CMML independent of CPSS-Mol classification

• Infrequent in CMML, AML-linked mutations (CEBPA, FLT3, or NPM1) detect a poor prognosis CMML group

Mutations commonly associated with acute myeloid leukemia (AML), such as CEBPA, FLT3, IDH1/2 and NPM1 are rarely found in chronic myelomonocytic leukemia (CMML) and their prognostic significance in CMML has not been clearly identified. In 127 CMML patients, we have retrospectively analyzed next-generation sequencing and PCR data from analyses of bone marrow samples performed at diagnosis of CMML. Seven patients harbored CEBPA mutations, eight FLT3 mutations, 12 IDH1 mutations, 26 IDH2 mutations and 11 NPM1 mutations. CMML patients harboring CEBPA, FLT3, and/or NPM1 mutations (mutCFN)were more frequently associated with the myeloproliferative subtype (MP-CMML) , a high prevalence of severe cytopenia, and elevated blast counts. Regardless of their CPSS-Mol classification, mutCFN CMML patients had a poor prognosis, and the multivariate analysis identified mutCFN as an independent marker of overall survival. The genetic profile of these mutCFN CMML patients closely resembled that of AML, with higher-risk clinical characteristics. Our findings lead us to suggest including the assessment of these mutations in CMML prognostic models and treating these patients with AML-type therapies, including intensive chemotherapy and allogeneic stem cell transplantation, whenever feasible, and consider certain targeted therapies approved for use in AML.