To further explore the genetics of CML progression, Giotopoulos et al. crossed the BCR-ABL mouse to mice harboring the GrOnc transposon and Mx1-Cre mediated activation of RosaSbaseLSL SB system (BCR-ABL; SB) (104). This evidence concerns the gene BCR and chronic myelogenous leukemia, BCR-ABL1 positive.