CXCL12 and breast cancer: Further, the present study shows that treatment with TAM and TRAN as a single or in combination inhibited CXCR4 mRNA expression levels and CXCL12 expression at protein and mRNA expression levels in MCF-7 and MDA-MB-231cells, suggesting that TAM and TRAN as a single or in combination may suppress metastases by down-regulating the expression of CXCR4 mRNA expression levels and CXCL12 at protein and mRNA levels breast cancer cells.