Prasad et al. [32] found that ROBO1 and ROBO2 were expressed in several breast cancer cell lines and that SLIT2 inhibited CXCL12/CXCR4-induced chemotaxis, invasion, adhesion, and secretion of MMP-2 and MMP-9 in breast cancer cells. This evidence concerns the gene CXCR4 and breast cancer.