CXCR4 and breast cancer: As shown, epidermoid carcinoma cells A431, T cell lymphoma cells SupT1, mammary gland adenocarcinoma cells MDA-MB231 and 4T1 cells, a mouse model of stage IV human breast cancer, expressed CXCR4 and were therefore proper model cell lines for further examination of the binding of (JM173)3-Avi-C3 and the delivery of C3 into their cytosol (Figure S3).