ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: In the phase 3 “International Randomized Study of Interferon and STI571” (IRIS) trial, rapid reduction in the BCR-ABL+ cells pool by imatinib at 400 mg QD in the majority of newly diagnosed chronic-phase (CP)-CML patients translated into a dramatic drop of progression to advanced-phase CML, an outstanding medical breakthrough [4].