title: Genomic aberrations in pediatric gliomas and embryonal tumors.
abstract: The pathogenesis of pediatric central nervous system tumors is poorly understood. To increase knowledge about the genetic mechanisms underlying these tumors, we performed genome-wide screening of 17 pediatric gliomas and embryonal tumors combining G-band karyotyping and array comparative genomic hybridization (aCGH). G-banding revealed abnormal karyotypes in 56% of tumor samples (9 of 16; one failed in culture), whereas aCGH found copy number aberrations in all 13 tumors examined. Pilocytic astrocytomas (n = 3) showed normal karyotypes or nonrecurrent translocations by karyotyping but the well-established recurrent gain of 7q34 and 19p13.3 by aCGH. Our series included one anaplastic oligoastrocytoma, a tumor type not previously characterized genomically in children, and one anaplastic neuroepithelial tumor (probably an oligoastrocytoma); both showed loss of chromosome 14 by G-banding and structural aberrations of 6q and loss of 14q, 17p, and 22q by aCGH. Three of five supratentorial primitive neuroectodermal tumors showed aberrant karyotypes: two were near-diploid with mainly structural changes and one was near-triploid with several trisomies. aCGH confirmed these findings and revealed additional recurrent gains of 1q21-44 and losses of 3p21, 3q26, and 8p23. We describe cytogenetically for the first time a cribriform neuroepithelial tumor, a recently identified variant of atypical teratoid/rhabdoid tumor with a favorable prognosis, which showed loss of 1p33, 4q13.2, 10p12.31, 10q11.22, and 22q by aCGH. This study indicates the existence of distinct cytogenetic patterns in pediatric gliomas and embryonal tumors; however, further studies of these rare tumors using a multimodal approach are required before their true genomic aberration pattern can be finally established.
authors: Section for Cancer Cytogenetics, Institute for Medical Informatics, Oslo University Hospital, The Norwegian Radium Hospital, Oslo, Norway. h.s.s.dahlback@medisin.uio.no
authors: Hanne-Sofie S
authors: HS
authors: Dahlback
authors: Petter
authors: P
authors: Brandal
authors: Ludmila
authors: L
authors: Gorunova
authors: Eva
authors: E
authors: Widing
authors: Torstein R
authors: TR
authors: Meling
authors: Bård K
authors: BK
authors: Krossnes
authors: Sverre
authors: S
authors: Heim
mesh_terms: D016543:Central Nervous System Neoplasms / Q000175:diagnosis / Q000196:embryology / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D002871:Chromosome Banding; D055028:Comparative Genomic Hybridization; D020732:Cytogenetic Analysis; D005260:Female; D015894:Genome, Human; D023281:Genomics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015994:Incidence; D007223:Infant; D007621:Karyotyping; D008297:Male; D018242:Neuroectodermal Tumors, Primitive / Q000175:diagnosis / Q000196:embryology / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D009664:Norway; D011446:Prospective Studies