title: Indications for a tumor suppressor gene at 22q11 involved in the pathogenesis of ependymal tumors and distinct from hSNF5/INI1.
abstract: Ependymomas account for approximately 9% of all neuroepithelial tumors and represent the most frequent neuroepithelial tumors of the spinal cord. In adults, allelic loss of chromosome arm 22q occurs in up to 60% of the cases studied. Some of these tumors show an altered neurofibromatosis type 2 (NF2) gene; in others, NF2 appears to be unaffected, indicating the involvement of another tumor suppressor gene. Recently, the tumor suppressor gene hSNF5/INI1, located on 22q11.23, has been shown to contribute to the pathogenesis of renal and extrarenal rhabdoid tumors. In addition, this gene may be responsible for a new hereditary syndrome predisposing to a variety of tumors designated "rhabdoid predisposition syndrome." In the present study, we analyzed a series of 53 ependymal tumors of 48 patients [4 myxopapillary ependymomas (WHO grade I), 3 subependymomas (WHO grade I), 18 ependymomas (WHO grade II), 21 anaplastic ependymomas (WHO grade III) and 2 ependymoblastomas (WHO grade IV)] for mutations and homozygous deletions in the coding region of the hSNF5/INI1 gene and for allelic loss of its flanking chromosomal regions in 39 ependymal tumors of 35 patients. Allelic loss was detected in 11 of 35 informative primary ependymal tumors (31%) with a common region of overlap covered by the markers D22S257 and D22S310 on 22q11 including the marker D22S301. However, a detailed molecular analysis of 53 ependymal tumors for mutations and homozygous deletion of the hSNF5/INI1 gene revealed no alterations. We conclude that the hSNF5/INI1 gene is not involved in the pathogenesis of human ependymal tumors with allelic loss on chromosome arm 22q and an intact NF2 locus. In addition, our study localizes a putative ependymoma tumor suppressor gene(s) to a domain of chromosome arm 22q flanked by the microsatellite markers D22S257 and D22S310.
authors.affiliation: Department of Neurology, University of Bonn Medical Center, Germany.
authors.forename: J A
authors.initials: JA
authors.lastname: Kraus
authors.forename: W
authors.initials: W
authors.lastname: de Millas
authors.forename: N
authors.initials: N
authors.lastname: Sörensen
authors.forename: C
authors.initials: C
authors.lastname: Herbold
authors.forename: C
authors.initials: C
authors.lastname: Schichor
authors.forename: J C
authors.initials: JC
authors.lastname: Tonn
authors.forename: O D
authors.initials: OD
authors.lastname: Wiestler
authors.forename: A
authors.initials: A
authors.lastname: von Deimling
authors.forename: T
authors.initials: T
authors.lastname: Pietsch
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000235:genetics* / Q000473:pathology; D002675:Child, Preschool; D002868:Chromosomal Proteins, Non-Histone; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D004806:Ependymoma / Q000235:genetics* / Q000473:pathology; D018628:Gene Dosage; D016147:Genes, Tumor Suppressor; D006801:Humans; D007223:Infant; D019656:Loss of Heterozygosity; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D011110:Polymorphism, Genetic; D018807:Polymorphism, Single-Stranded Conformational; D000071796:SMARCB1 Protein; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors