ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: One of the prime examples of a breakthrough in oncology was the development of imatinib, an inhibitor of the Abl tyrosine kinase, for the targeted therapy of chronic myelogenous leukemia (Figure 1), a disease caused by the emergence of the BCR-Abl fusion protein through a unique chromosomal translocation [4].