BCR and chronic myelogenous leukemia, BCR-ABL1 positive: This early knowledge of the BCR::ABL1 fusion gene has resulted in CML being the target of many laboratory and clinical firsts, including bone marrow transplantation [5], international standardisation of molecular monitoring [6, 7] and one of the first targeted cancer therapies, imatinib, a tyrosine kinase inhibitor [8].