As altered CXCR4/CXCL12-mediated chemotaxis and growth were observed upon co-expression of the two CXCL12 receptors in NB cells, such ligand scavenging role for CXCR7 appears likely, and may enable a negative regulation of CXCR4/CXCL12-mediated fonctions in NB. The gene discussed is ACKR3; the disease is neuroblastoma.