In fact, blockade of CXCR4 only partially inhibited migration of cancer cells to CXCL12 gradients in vivo [124] because the relationship between CXCR7 (the secondary receptor of CXCL12) and CXCR3 via their shared ligand CXCL11 has made this interaction more complex. Here, ACKR3 is linked to cancer.