However, induced CXCR7 protein levels might be too low, or post-translationally modified, as they could be neither detected at the cell surface (FACS analyses), nor in the intracellular space of treated NB cells (Immunofluorescence assays), by both anti-CXCR7 antibodies used in this study (data not shown). Here, ACKR3 is linked to neuroblastoma.