Since BCR-ABL1-positive cells (called CML cells in the following) are quite dependent on BCR-ABL1 for their growth and survival, ABL1-specific tyrosine kinase inhibitors (TKIs) have clinically demonstrated substantial reduction of CML cells and restoration of normal hematopoiesis in the vast majority of CP-CML patients3–7. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.