JAK2 and myeloproliferative neoplasm, unclassifiable: Compared to other MDS/MPN subtypes, MDS/MPN-U patients exhibited the most heterogeneous mutational profiles, with high frequencies observed in TET2 (17/44; 38.6%), ASXL1 (12/44; 27.3%), SRSF2 (12/44, 27.3%), JAK2 (9/44; 20.5%), and SF3B1 (9/44; 20.5%) (Figure 4D).