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. Int. J. Cancer 89:395–402, 2000. © 2000 Wiley‐Liss, Inc.