RAS mutations contribute to evolution of chronic myelomonocytic leukemia to the proliferative variant.

Purpose: The biological and clinical heterogeneity of chronic myelomonocytic leukemia features renders its classification difficult. Moreover, because of the limited knowledge of the mechanisms involved in malignant evolution, chronic myelomonocytic leukemia remains a diagnostic and therapeutic challenge and a poor prognosis disease. We aimed to verify the biological and clinical significance of the discrimination, based on the leukocyte count, between myelodysplastic chronic myelomonocytic leukemia (MD-CMML) and myeloproliferative chronic myelomonocytic leukemia (MP-CMML).