CXCR4 and breast cancer: Because expression of CXCR4 in BC cells has been found to be associated with increased tube formation (angiogenesis), and induction of EMT, we used a BC cell line that does not express CXCR4 to study whether Nef-M1 peptide inhibits angiogenesis or inhibits EMT process through the CXCR4 receptor.