Another CXCR4 antagonist, BKT140, effectively reduced the growth of the tumors arising from subcutaneous injection of a human CML cell line, K562, and its combination with imatinib essentially abrogated tumor growth, resulting in 95% reduction in tumor size and weight, together with extensive necrotic tissue damage [80]. This evidence concerns the gene CXCR4 and chronic myelogenous leukemia, BCR-ABL1 positive.