ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Chronic myeloid leukaemia (CML) is a malignant pluripotent haematopoietic stem cell disease characterized by the expression of the BCR/ABL1 fusion gene, a constitutively activated tyrosine kinase which commonly results from the formation of the Philadelphia chromosome (Ph) after a t(9;22)(q34;q11) or related variant rearrangement [1].