MYCN expression is not prognostic of adverse outcome in advanced-stage neuroblastoma with nonamplified MYCN

Purpose: The clinical significance of MYCN expression in children with neuroblastoma (NB) remains controversial. To determine the prognostic significance of MYCN expression in the absence of MYCN amplification, we analyzed MYCN mRNA and protein expression in tumors from 69 patients. Patients and Methods: Sixty-nine NB tumor samples with nonamplified MYCN from patients with stage C or D disease were obtained from the Pediatric Oncology Group Neuroblastoma Tumor Bank. MYCN mRNA was analyzed using a real-rime reverse transcriptase polymerase chain reaction assay, and MYCN protein was examined by Western blot analyses. Results: The estimated 5-year event-free survival (EFS) and survival (5) rates plus SE for the cohort were 57% +/- 17% and 60% +/- 16%, respectively. infants younger than 1 year had significantly higher rates of EFS and S than children greater than or equal to 1 year of age (P = .003 and P < .001, respectively); patients with stage C disease had better outcome than those with stage, D NE (P < .001); and patients with hyperdiploid tumors held better outcome than those with diploid NE (P < .001). Surprisingly, outcome war slightly better for patients with high versus low levels of MYCN mRNA expression (4-year 5, 70% +/- 13% v50% +/- 16%; P = .290), and for patients with tumors that expressed MYCN protein (4-year S, 73% +/- 19% v 53% +/- 15%, respectively; P = .171). Conclusion: High levels of MYCN expression are not prognostic of adverse outcome in patients with advanced-stage NE with nonamplified MYCN. A trend associating high levels of MYCN expression with improved outcome was observed. (C) 2000 by American Society of Clinical Oncology.