MDM2 and neuroblastoma: Analysis of neuroblastoma cell lines reported to date with aberrations in the p53/MDM2/p14ARF pathway demonstrates that 31/40 (78%) of these cell lines are MYCN amplified and predominantly established following previous cytotoxic therapy at relapse (Table 1), when abnormalities of the p53 pathway in neuroblastoma tumors have also been previously reported (reviewed by Tweddle et al., 2003; Carr-Wilkinson et al., 2010).