aCML was characterized by high frequencies of ASXL1 (62.5%) and SETBP1 (50%) mutations, while MDS/MPN-U cases showed the most heterogeneous molecular features with mutations in TET2 (38.6%), ASXL1 (27.3%), SRSF2 (27.3%), JAK2 (20.5%), and SF3B1 (20.5%). This evidence concerns the gene TET2 and atypical chronic myeloid leukemia, BCR-ABL1 negative.