A functional interaction between the IGF1R and CXCR4 was documented in breast cancer cell lines [249] where CXCR4 and IGF1R directly interacted at the cell membrane, thereby inducing IGF1-evoked CXCR4 transactivation and cell migration independently of its cognate ligand CXCL12 [249]. Here, CXCL12 is linked to breast cancer.