Recently, the anti-neoplastic agent Balixafortide (a potent and selective CXCR4 antagonist) (Polyphor) in combination with Eribulin (non-taxane, anti-microtubule drug) has been successfully employed in stage IV breast cancer in a phase Ib/proof of concept clinical trial (NCT01837095). This evidence concerns the gene CXCR4 and breast carcinoma.