CXCR4 and breast cancer: In 2017, a preclinical study showed that two CXCR4 inhibitors (AMD3100 and TN14003) significantly reduced tumor growth in a HER2 overexpressing tumor xenographs, including Herceptin and Docetaxel-resistant, suggesting that CXCR4 inhibition could be a useful strategy for treat HER2 breast cancer patients [16].