Considering the evidence that p53 mutations at diagnosis are rare, but abnormalities of the p53/MDM2/p14ARF pathway are common in relapsed neuroblastomas [58,59,60], DDR deficiency along with p53-related pathway abnormalities may contribute to the pathogenesis of unfavorable neuroblastomas, as they do in other tumors. The gene discussed is MDM2; the disease is neuroblastoma.