C-MYC expression in medulloblastoma and its prognostic value.

To identify prognostic factors in medulloblastoma, a common malignant brain tumor of childhood, expression of the oncogene c-myc was examined at the mRNA level by in situ hybridization. c-myc mRNA expression was observed in 30 of 72 tumors (42%). The c-myc gene copy number was determined by quantitative PCR from genomic DNA of paraffin-embedded tumors. c-myc gene amplification was present in 5 of 62 cases (8.3%). Therefore, c-myc amplification was obviously not the cause of c-myc mRNA expression in most samples. Kaplan-Meier estimation revealed a significant correlation between c-myc mRNA expression and survival (total mean follow-up 4.6 +/- 3.6 years, log-rank p = 0.02). Multivariate logistic regression analysis including sex, age, histological type, degree of surgical resection and expression of synaptophysin, GFAP and c-myc, was carried out on 54 patients who received both radiotherapy and chemotherapy. The analysis identified expression of c-myc as an independent predictive factor of death from disease. Copyright 2000 Wiley-Liss, Inc.