title: Molecular genetic analysis of ependymal tumors. NF2 mutations and chromosome 22q loss occur preferentially in intramedullary spinal ependymomas.
abstract: Ependymal tumors are heterogeneous with regard to morphology, localization, age at first clinical manifestation, and prognosis. Several molecular alterations have been reported in these tumors, including allelic losses on chromosomes 10, 17, and 22 and mutations in the NF2 gene. However, in contrast to astrocytic gliomas, no consistent molecular alterations have been associated with distinct types of ependymal tumors. To evaluate whether morphological subsets of ependymomas are characterized by specific genetic lesions, we analyzed a series of 62 ependymal tumors, including myxopapillary ependymomas, subependymomas, ependymomas, and anaplastic ependymomas, for allelic losses on chromosome arms 10q and 22q and mutations in the PTEN and NF2 genes. Allelic losses on 10q and 22q were detected in 5 of 56 and 12 of 54 tumors, respectively. Six ependymomas carried somatic NF2 mutations, whereas no mutations were detected in the PTEN gene. All six of the NF2 mutations occurred in ependymomas of WHO grade II and were exclusively observed in tumors with a spinal localization (P = 0.0063). These findings suggest that a considerable fraction of spinal ependymomas are associated with molecular events involving chromosome 22 and that mutations in the NF2 gene may be of primary importance for their genesis. Furthermore, our data suggest that the more favorable clinical course of spinal ependymomas may relate to a distinct pattern of genetic alterations different from that of intracerebral ependymomas.
authors.affiliation: Department of Neuropathology, University of Bonn Medical Center, Bonn Charité, Humboldt University, Berlin, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Ebert
authors.forename: M
authors.initials: M
authors.lastname: von Haken
authors.forename: B
authors.initials: B
authors.lastname: Meyer-Puttlitz
authors.forename: O D
authors.initials: OD
authors.lastname: Wiestler
authors.forename: G
authors.initials: G
authors.lastname: Reifenberger
authors.forename: T
authors.initials: T
authors.lastname: Pietsch
authors.forename: A
authors.initials: A
authors.lastname: von Deimling
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D002675:Child, Preschool; D002872:Chromosome Deletion; D002879:Chromosomes, Human, Pair 10; D002892:Chromosomes, Human, Pair 22; D004806:Ependymoma / Q000235:genetics*; D005260:Female; D016515:Genes, Neurofibromatosis 2 / Q000235:genetics; D006801:Humans; D019656:Loss of Heterozygosity; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D018895:Microsatellite Repeats; D008875:Middle Aged; D009154:Mutation; D025581:Neurofibromin 2; D051059:PTEN Phosphohydrolase; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics; D018807:Polymorphism, Single-Stranded Conformational; D013120:Spinal Cord Neoplasms / Q000235:genetics*; D013125:Spinal Neoplasms / Q000235:genetics*; D025521:Tumor Suppressor Proteins
chemical_list: D008565:Membrane Proteins; D025581:Neurofibromin 2; D025521:Tumor Suppressor Proteins; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human