ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Chronic myeloid leukaemia (CML) is a myeloproliferative neoplasm that originates from haematopoietic stem cells and is characterised by a chromosomal translocation t(9;22)(q34;q11.2), which forms the Philadelphia chromosome (Ph) containing the BCR::ABL1 fusion gene [1].