As the two receptors elicited specific expression patterns in NB tissues, our TMA analyses suggest a complex contribution of the CXCR7 and CXCR4 receptors in NB pathogenesis, which may be tightly modulated by a permanent cross-talk with their common ligand CXCL12, highly produced by tumor microenvironment. The gene discussed is CXCL12; the disease is neuroblastoma.