In line with evidence from ovarian (Furuya et al., 2005) and bladder carcinoma cell lines (Mitsuzuka et al., 2005), elevated CD9 expression was found to suppress neuroblastoma cell migration and invasion, whilst low CD9 tetraspanin expression within primary neuroblastomas correlated with MYCN amplification, high-risk disease and poor patient survival. This evidence concerns the gene MYCN and neuroblastoma.