ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Prior to the use of tyrosine kinase inhibitors forthe treatment of CML a molecular response was rarelyachieved and it was therefore not feasible to routinelymonitor BCR-ABL transcript levels, with the exceptionof patients that underwent bone marrow transplantation[1,2,3,4,5,6].