CXCR4 and breast cancer: Considering the circumstance of CXCR4/CXCL12 axis in breast cancer metastasis, we investigated the effects of tamoxifen and tranilast as a single or in combination on CXCR4 and CXCL12 mRNA and CXCL12 protein expression levels and also on two in-vitro invasion models in MCF-7 and MDA-MB-231 breast cancer cell lines.