SRSF2 and myeloproliferative neoplasm, unclassifiable: One additional MDS/MPN-U case in the progressed cohort (case 15) displayed four different somatic mutations (DNMT3A, ETV6, SRSF2 and TET2) and was found to have the highest allelic frequency in the TET2 clone, suggesting itself to be a “TET2-first” case as well.