CXCR4 and breast cancer: Although Akekawatchai et al. have found that IGF1 could transactivate CXCR4 signaling in breast cancer cell line independently of SDF-1α to promote cell migration25, we have showed that cross-talk between IGF1R and CXCR4 might be transactivated dually by their specific ligands IGF1 and SDF-1α in hDSCs.