Whilst the presence of multiple mutations per patient are commonly detected in blast crisis CML, acute myeloid leukemia (AML) and myelodysplastic neoplasms (MDS) [29–31], 47/53 (89%) of all affected patients in this study showed only one mutation in addition to BCR::ABL1 at diagnosis indicating that the clonal architecture in CML might be less complex compared to other myeloid malignancies (Fig. 1). The gene discussed is BCR; the disease is blast phase chronic myelogenous leukemia, BCR-ABL1 positive.