CXCR4/CXCL12 can mediate the adhesion of tumor cells to stromal cells in tumor microenvironments, and the resulting interactions provide survival, anti-apoptosis and drug-resistance signals.24,25 Therefore, we next studied whether E5 could inhibit the adhesion of 4T1 cells to MS-5 cells. Here, CXCL12 is linked to neoplasm.