In both patients, the conversion from MPN to CMML was associated with a drop in the JAK2 V617F clone and an increase in clones that are typically found in CMML, such as SRSF2, KRAS and IDH1. Of course, we cannot generalize this observation to all CMML-developing MPN patients. Here, JAK2 is linked to chronic myelomonocytic leukemia.