CML (chronic myeloid leukemia) or chronic granulocytic leukaemia is one of the myeloproliferative neoplasms (MPN) characterized by proliferation of a pluripotential stem cell that can differentiate along the granulocytic lineage and is consistently associated with the BCR-ABL1 fusion gene (1). The gene discussed is ABL1; the disease is myeloproliferative disorder.