CMML is a disease of aging, and previous studies suggest that it represents the leukemic conversion of the myelomonocytic-lineage-biased aged hematopoietic system, in which mutated co-expression of TET2 and SRSF2 results in clonal hematopoiesis skewed toward monocytosis [52]. Here, SRSF2 is linked to chronic myelomonocytic leukemia.