title: Radiation-induced glioblastoma in a medulloblastoma patient: a case report with molecular features.
abstract: We report a case of glioblastoma (GBM) occurring 8 years after radiation therapy for a medulloblastoma. A 15-year-old boy underwent surgery and radiotherapy for a medulloblastoma and 8 years later he developed a second tumor at the same site. The second lesion showed different histological and molecular features, was diagnosed as a glioblastoma and fulfilled the criteria of radiation-induced neoplasm. Mutational analysis of the p53 gene showed a C to G transition at codon 176 in tumor DNA. LOH was detected at 17p and 19q. The tumor also showed O6-methylguanine-DNA methyl-transferase (MGMT) promoter methylation and no amplification of EGF receptor. In conclusion, the radiation-induced MGMT hyper-methylation and p53 mutations may have a role in the development of a subgroup of radio-induced glioma (RIG), suggesting that these molecular alterations directly cooperate in the genesis of the post-irradiation GBM. Moreover RIGs seem to be a heterogeneous group of tumors that may resemble either primary or secondary GBM.
authors.affiliation: Division of Neuropathology, Intituto Nazionale Neurologico C Besta, Milano, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Gessi
authors.forename: Emanuela
authors.initials: E
authors.lastname: Maderna
authors.forename: Sara
authors.initials: S
authors.lastname: Guzzetti
authors.forename: Graziella
authors.initials: G
authors.lastname: Cefalo
authors.forename: Maura
authors.initials: M
authors.lastname: Massimino
authors.forename: Carlo L
authors.initials: CL
authors.lastname: Solero
authors.forename: Gaetano
authors.initials: G
authors.lastname: Finocchiaro
authors.forename: Bianca
authors.initials: B
authors.lastname: Pollo
mesh_terms: D000293:Adolescent; D002648:Child; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics; D002888:Chromosomes, Human, Pair 19 / Q000235:genetics; D019175:DNA Methylation; D066246:ErbB Receptors / Q000235:genetics; D005784:Gene Amplification; D016158:Genes, p53; D005909:Glioblastoma / Q000209:etiology* / Q000235:genetics* / Q000473:pathology; D006801:Humans; D019656:Loss of Heterozygosity; D008297:Male; D008527:Medulloblastoma / Q000235:genetics* / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D009154:Mutation; D009381:Neoplasms, Radiation-Induced / Q000235:genetics* / Q000473:pathology; D016609:Neoplasms, Second Primary / Q000209:etiology* / Q000235:genetics / Q000473:pathology; D011401:Promoter Regions, Genetic
chemical_list: D066246:ErbB Receptors