As shown in Figure 1, two selected invasive NB cell lines, IGR-N91, SH-SY5Y, displayed constitutive levels of CXCR4 surface protein expression (54% and 97% positive cells respectively), while the non-invasive IGR-NB8 cell line expressed very little if any surface CXCR4 (1.48% positive cells). This evidence concerns the gene CXCR4 and neuroblastoma.