CXCL12 and neuroblastoma: In contrast, although not statistically significant due to heterogeneity and the low number of mice in this study, CXCR4 receptor (NB8x4 and NB8x4x7) was able to strongly enhance the number of lung metastases, supporting a CXCR4 receptor influence on NB cell invasion of the lungs, and a possible involvement of the CXCR4/CXCL12 axis in lungs metastases occurrence in patient with highly disseminated NB disease.