CXCR4 and neuroblastoma: In a further set of experiments, we investigated whether different NB cells (SH-SY5Y, GI-LI-N and Htla-230), chosen for their ability to in vivo metastasize upon systemic or orthotopically administration and for their different constitutive CXCR4 expression, acquired higher migration capability to CXCL12, after preincubation with hMSCs.