MDM2 and neuroblastoma: Moreover, observations that inactivation of the p53/MDM2/p14ARF pathway in relapsed neuroblastoma is predominantly due to lesions upstream of p53 combined with the reported therapeutic efficacy of Nutlin-3 in p53 wt multi-drug-resistant preclinical models of neuroblastoma with metastatic burden (Van Maerken et al., 2009a), highly support reactivation of p53 by inhibiting MDM2 as an attractive treatment option for metastatic relapsed neuroblastoma.