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Buccoliero AM, Caporalini C, Moscardi S, Cetica V, Mei D, Conti V, Nozzoli F, Bonaudo C, Battista F, Giordano F, Mura R, Spacca B, Mussa F, D'Onofrio V, Guerrini R, Genitori L, Scagnet M. Leat-associated seizures the possible role of EAAT2, pyruvate carboxylase and glutamine synthetase. Epilepsy Res 2024; 199:107258. [PMID: 38086219 DOI: 10.1016/j.eplepsyres.2023.107258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 10/27/2023] [Accepted: 11/09/2023] [Indexed: 01/13/2024]
Abstract
BACKGROUND Drug-resistant epilepsy is a common condition in patients with brain neoplasms. The pathogenesis of tumor-associated seizures is poorly understood. Among the possible pathogenetic mechanisms, the increase in glutamate concentration has been proposed. Glutamate transporters, glutamine synthetase and pyruvate carboxylase are involved in maintaining the physiological concentration of glutamate in the intersynaptic spaces. In our previous research on angiocentric gliomas, we demonstrated that all tumors lacked the expression of the main glutamate transporter EAAT2, while the expression of glutamine synthetase and pyruvate carboxylase was mostly preserved. METHODS In the present study, we evaluated the immunohistochemical expression of EAAT2, glutamine synthetase and pyruvate carboxylase in a heterogeneous series of 25 long-term epilepsy-associated tumors (10 dysembryoplastic neuroepithelial tumors, 7 gangliogliomas, 3 subependymal giant cell astrocytomas, 3 rosette forming glioneuronal tumors, 1 diffuse astrocytoma MYB- or MYBL1-altered and 1 angiocentric glioma). In order to evaluate the incidence of variants in the SLC1A2 gene, encoding EAAT2, in a large number of central nervous system tumors we also queried the PedcBioPortal. RESULTS EAAT2 protein expression was lost in 9 tumors (36 %: 3 dysembryoplastic neuroepithelial tumors, 1 ganglioglioma, 3 subependymal giant cell astrocytomas, 1 diffuse astrocytoma MYB- or MYBL1-altered and 1 angiocentric glioma). Glutamine synthetase protein expression was completely lost in 2 tumors (8 %; 1 ganglioglioma and 1 diffuse astrocytoma MYB- or MYBL1-altered). All tumors of our series but rosette forming glioneuronal tumors (in which neurocytic cells were negative) were diffusely positive for pyruvate carboxylase. Consultation of the PedcBioPortal revealed that of 2307 pediatric brain tumors of different histotype and grade, 20 (< 1%) had variants in the SLC1A2 gene. Among the SLC1A2-mutated tumors, there were no angiocentric gliomas or other LEATs CONCLUSIONS: In conclusion, unlike angiocentric gliomas where the EAAT2 loss is typical and constant, the current study shows the loss of EAAT2 expression only in a fraction of the LEATs. In these cases, we may hypothesize some possible epileptogenic role of the EAAT2 loss. The retained expression of pyruvate carboxylase may contribute to determining a pathological glutamate excess unopposed by glutamine synthetase that resulted expressed to a variable extent in the majority of the tumors. Furthermore, we can assume that the EAAT2 loss in brain tumors in general and in LEATs in particular is more conceivably epigenetic.
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Affiliation(s)
| | | | - Selene Moscardi
- Pathology Unit, Meyer Children's Hospital IRCCS, Florence, Italy
| | - Valentina Cetica
- Department of Neurosciences, Psychology, Drug Research, and Child Health (NEUROFARBA), University of Florence, Meyer Children's Hospital IRCCS, Florence, Italy
| | - Davide Mei
- Department of Neurosciences, Psychology, Drug Research, and Child Health (NEUROFARBA), University of Florence, Meyer Children's Hospital IRCCS, Florence, Italy
| | - Valerio Conti
- Department of Neurosciences, Psychology, Drug Research, and Child Health (NEUROFARBA), University of Florence, Meyer Children's Hospital IRCCS, Florence, Italy
| | - Filippo Nozzoli
- Histopathology and Molecular Diagnostics, Careggi University Hospital, Florence, Italy
| | - Camilla Bonaudo
- Department of Neurosciences, Psychology, Drug Research, and Child Health (NEUROFARBA), Careggi University Hospital, Florence, Italy
| | - Francesca Battista
- Department of Neurosciences, Psychology, Drug Research, and Child Health (NEUROFARBA), Careggi University Hospital, Florence, Italy
| | - Flavio Giordano
- Department of Neurosciences, Psychology, Drug Research, and Child Health (NEUROFARBA), University of Florence, Meyer Children's Hospital IRCCS, Florence, Italy
| | - Regina Mura
- Department of Neurosurgery, Meyer Children's Hospital IRCCS, Florence, Italy
| | - Barbara Spacca
- Department of Neurosurgery, Meyer Children's Hospital IRCCS, Florence, Italy
| | - Federico Mussa
- Department of Neurosurgery, Meyer Children's Hospital IRCCS, Florence, Italy
| | | | - Renzo Guerrini
- Department of Neurosciences, Psychology, Drug Research, and Child Health (NEUROFARBA), University of Florence, Meyer Children's Hospital IRCCS, Florence, Italy
| | - Lorenzo Genitori
- Department of Neurosciences, Psychology, Drug Research, and Child Health (NEUROFARBA), Careggi University Hospital, Florence, Italy
| | - Mirko Scagnet
- Department of Neurosurgery, Meyer Children's Hospital IRCCS, Florence, Italy
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Abstract
Long-term epilepsy-associated tumors (LEATs) include a series of neoplasms that commonly occur in children, adolescents, or young adults, have an astrocytic or glioneuronal lineage, are histologically benign (WHO grade1) with a neocortical localization predominantly situated in the temporal lobes. Clinically, chronic refractory epilepsy is usually the unique symptom. Gangliogliomas (GG) and dysembryoplastic neuroepithelial tumors (DNT) are the most common representative entities besides pilocytic astrocytomas (PA) and angiocentric gliomas (AG). Recent molecular studies have defined new clinicopathological entities, which are recognized by the WHO 2021 classification of brain tumors. Some of them such as diffuse astrocytoma MIB or MYBL1 altered, polymorphous low-grade neuroepithelial tumor of the young (PLNTY), and multilocular and vacuolating neuronal tumor (MVNT) are currently considered LEATs. The relationship between LEATs and epilepsy is still a matter of debate, and there is a general agreement about the beneficial effects of an early neurosurgical intervention on the clinical outcome.
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Affiliation(s)
- Sergio Rosemberg
- Universidade de São Paulo, Faculdade de Medicina, Departamento de Patologia, São Paulo SP, Brazil.
- Santa Casa de São Paulo, Faculdade de Ciências Médicas, São Paulo SP, Brazil.
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