CXCR4 and breast cancer: In breast cancer the CXCR4 mRNA promotes metastasis not only through its protein, the CXCR4 chemokine receptor, but also through the CXCR4 3′UTR that sponges the tumor-suppressive miR-146a, thus leading to the upregulation of TRAF6 and EGFR, two oncoproteins that activate the NF-κB pathway.148