Klein et al. demonstrated how the overexpression of CXCR4 or stimulation with CXCL12 promoted proliferation and tumor growth in neuroblastoma cells through the activation of the MAPK signaling pathway; furthermore, the inhibition of CXCR4 with the high-affinity CXCR4 antagonist BL-8040 prevented tumor growth and reduced tumor cell survival [34]. This evidence concerns the gene CXCR4 and neuroblastoma.