CXCR4 and cancer: As far as its role in the metastatic process is concerned, CXCL12 promotes the mobilization of cancer cells from the primary tumor to the metastatic niche; therefore, targeting the CXCL12/CXCR4/CXCR7 axes may significantly improve therapeutic outcomes in patients, although the precise mechanisms of how the CXCL12/CXCR4/CXCR7 axes participate in metastasis are still unclear and need to be further elucidated.