For the first time, the induction of CML-like myeloproliferative syndrome was observed in irradiated recipient mice transplanted with a retroviral vector encoding the BCR-ABL1 fusion protein to identify regions in this oncoprotein that are important for CML transformation in mice and design of TKIs [230]. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.