It has been suggested that SF3B1 mutation defines a unique entity within all myeloid neoplasms, but distinctive clinical and biological features and prognosis have been observed between MDS and MDS/MPN harboring this mutation, which would argue against the idea of classifying SF3B1-mutant myeloid neoplasms as a single entity (10–13). The gene discussed is SF3B1; the disease is myeloid neoplasm.