Prognostic value of N-myc oncogene amplification and S-100 protein positivity in children with neuroblastic tumors.

Data on 43 neuroblastic tumors (30 neuroblastomas and 13 ganglioneuroblastomas) obtained from 22 untreated and 21 pretreated children, were analyzed to determine the correlation between N-myc oncogene amplification and immunohistochemically identified S-100 protein positivity. Sixteen patients in whom the tumor showed significant amplification of N-myc (more than ten copies) died, irrespective of S-100 protein positivity and other conventional factors. Among 27 patients with low amplification of N-myc (less than ten copies), the estimated progression-free survival for those whose tumors had numerous S-100 protein-positive cells (P group), and few or no positive cells (N group) was 75% and 17%, respectively (p < 0.0001). Thus, in addition to N-myc oncogene amplification as a reliable indicator of outcome, S-100 protein positivity should be useful for prediction of prognosis in children with neuroblastic tumors showing low amplification of N-myc. Correlations among these results and other clinical factors are briefly discussed.