Since cells expressing BCR-ABL showed significantly higher proteasome levels than did BCR-ABL-negative cells and were more sensitive to induction of apoptosis by proteasome inhibitor[59], we test the combined effects of IM and proteasome inhibitors and report here that in vivo IM/BOR combination causes an intensified therapeutic efficacy without obvious toxicity, providing an alternative option for CML treatment. This evidence concerns the gene BCR and chronic myelogenous leukemia, BCR-ABL1 positive.