title: Reduced TSC2 RNA and protein in sporadic astrocytomas and ependymomas.
abstract: Individuals affected with tuberous sclerosis complex (TSC) develop several benign and malignant tumors at increased frequency, including astrocytomas. Tuberin, the protein product of the tuberous sclerosis complex-2 (TSC2) tumor suppressor gene, has been shown to directly inhibit cell growth and is expressed at high levels in normal central nervous system neurons and astrocytes. To determine whether TSC2 RNA and protein are reduced in astrocytomas from individuals without tuberous sclerosis, reverse transcriptase-polymerase chain reaction and immunoblotting analyses were performed on 49 adult astrocytomas, 10 pediatric astrocytomas, and 13 ependymomas. Eighteen of 40 (45%) high-grade (World Health Organization [WHO] grade III/IV) astrocytomas and 4 of 8 (50%) adult low-grade (WHO grade II) astrocytomas demonstrated reduced or absent TSC2 expression, including 1 giant cell astrocytoma, whereas none of the 10 pediatric low-grade astrocytomas analyzed showed a reduction in TSC2 expression. Reduced or absent tuberin was observed in 2 of 6 (33%) ependymomas analyzed. These data demonstrate, for the first time, that reduced or absent TSC2 expression may represent one of the critical genetic events associated with the development of sporadic adult, but not pediatric, astrocytomas.
authors.affiliation: Laboratory of Cellular Oncology, National Cancer Institute, Bethesda, MD, USA.
authors.forename: R
authors.initials: R
authors.lastname: Wienecke
authors.forename: A
authors.initials: A
authors.lastname: Guha
authors.forename: J C
authors.initials: JC
authors.lastname: Maize
authors.forename: R L
authors.initials: RL
authors.lastname: Heideman
authors.forename: J E
authors.initials: JE
authors.lastname: DeClue
authors.forename: D H
authors.initials: DH
authors.lastname: Gutmann
mesh_terms: D000328:Adult; D000367:Age Factors; D001254:Astrocytoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D001932:Brain Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002648:Child; D017931:DNA Primers; D004806:Ependymoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D005091:Exons; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D006801:Humans; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D012097:Repressor Proteins / Q000096:biosynthesis* / Q000235:genetics; D014158:Transcription, Genetic; D014402:Tuberous Sclerosis / Q000235:genetics; D000077005:Tuberous Sclerosis Complex 2 Protein; D025521:Tumor Suppressor Proteins
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D012097:Repressor Proteins; C000624653:TSC2 protein, human; D000077005:Tuberous Sclerosis Complex 2 Protein; D025521:Tumor Suppressor Proteins