CXCR4 and chronic myelogenous leukemia, BCR-ABL1 positive: A TKI, imatinib, enhanced CXCR4 expression in CML cells and caused the migration of CML cells to the CXCL12-expressing bone marrow microenvironment niche, which provided CML cells with anti-apoptotic signals and subsequently resistance to imatinib [76].