Immunoblot analysis of monolayer cultures demonstrated also higher protein expression of CXCR4 in MNA (Kelly, SK-N-BE(2)) compared to MNN (SK-N-AS, SK-N-SH) cell lines, whereas the protein expression of BMI1 and NANOG did not correlate with the MycN status of the NB cell lines (Figure 7a). This evidence concerns the gene BMI1 and neuroblastoma.