Subependymal giant cell astrocytoma: a lesion with activated mTOR pathway and constant expression of glutamine synthetase
Autor: | Gianna Baroni, Chiara Caporalini, Lorenzo Genitori, Gian Luigi Taddei, Federico Mussa, Anna Maria Buccoliero, Mirko Scagnet, Selene Moscardi, Flavio Giordano |
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Rok vydání: | 2016 |
Předmět: |
Cortical tubers
Adult Male Pathology medicine.medical_specialty Adolescent Astrocytoma Pathology and Forensic Medicine 03 medical and health sciences Young Adult 0302 clinical medicine Glutamate-Ammonia Ligase Tuberous Sclerosis Glutamine synthetase Subependymal zone medicine Biomarkers Tumor Humans Child PI3K/AKT/mTOR pathway Glial fibrillary acidic protein biology Subependymal giant cell astrocytoma Brain Neoplasms TOR Serine-Threonine Kinases Infant General Medicine Cortical dysplasia medicine.disease Immunohistochemistry Neurology 030220 oncology & carcinogenesis Ribosomal protein s6 Child Preschool biology.protein Cancer research Female Neurology (clinical) 030217 neurology & neurosurgery Signal Transduction |
Zdroj: | Clinical neuropathology. 35(5) |
ISSN: | 0722-5091 |
Popis: | Subependymal giant-cell astrocytoma (SEGA) is a rare tumor associated with tuberous sclerosis complex (TSC). TSC mainly involves the central nervous system (CNS) where SEGA, subependymal nodules, and cortical tubers may be present. First studies suggested the astrocytic nature of SEGA while successive studies demonstrated the mixed glio-neuronal nature. There are similarities between TSC-associated CNS lesions and type IIb focal cortical dysplasia (FCD). In all these pathologies, mammalian target of rapamycin (mTOR) pathway activation has been demonstrated. Recent data evidenced that balloon cells in FCD IIb express glutamine synthetase (GS). GS is involved in the clearance of glutamate. Cells expressing GS might exert an antiepileptic role. We evaluated by immunohistochemistry the glial fibrillary acidic protein (GFAP), neurofilaments (NF), and GS expression and the mTOR status (mTOR and phosphorylated ribosomal protein S6) in 16 SEGAs and 2 cortical tubers. Our purpose was to emphasize the mixed nature of SEGA and to further investigate the similarities between TSC-related CNS lesions (in particular SEGA) and FCD IIb. We confirm the glio-neuronal nature and the common activation of the mTOR pathway in SEGAs. In addition, we report for the first time that these tumors, analogously to FCD IIb, commonly express GS. Notably, the expression of mTOR, phosphorylated ribosomal protein S6, and GS was restricted to gemistocytic-like GFAP-negative cells. GS expression and mTOR pathway activation were also documented in cortical tubers. Further studies are necessary to understand the significance of GS expression in SEGAs as well as in cortical tubers. |
Databáze: | OpenAIRE |
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