In the presence of imatinib, CML cells upregulate the expression of C-X-C chemokine receptor type 4 (CXCR-4), promoting the migration of leukemia cells to bone marrow niches and their chemoresistance in response to stimulation with stromal-derived factor (SDF)1 [146]. This evidence concerns the gene CXCR4 and chronic myelogenous leukemia, BCR-ABL1 positive.