Gene expression profile analysis of epilepsy-associated gangliogliomas

Epilepsy Related to Developmental Tumors and Malformations of Cortical Development

“…In addition, analysis of the gene expression profile of GG highlights developmental alterations of the balance between excitation and inhibition, with a prominent expression of mGluR5 and downregulation of several gammaaminobutyric acid (GABA)a receptor (GABA A R) subunits (including α1, α5, ß1, ß3, and δ), suggesting impairment of GABAergic inhibition [29,57,58]. A deregulation of the cation-chloride (NKCC1 and KCC2) cotransporters (CCTs), resembling the expression patterns observed in immature brain, has been reported in GGs [57,59], and may also actively contribute to the epileptogenicity of this tumor type via modulation of GABA receptors [60].…”

“…Altered expression of gap junction channels (connexins) resulting in a disturbed communication between glial cells may also contribute, potentially, to seizure development in brain tumors, including GNT [68,69]. Furthermore, the low expression of several potassium channel genes observed in GG suggests a disturbed ion homeostasis and transport that could represent an additional potential mechanism leading to increased excitability in GNT [57]. Interestingly, evaluation of the inward-rectifying potassium channel on astrocytes Kir4.1 in tumor specimens showed a significantly lower Kir4.1 expression in the specimens of patients with epilepsy compared to patients without epilepsy [70].…”

“…Interestingly, both gene expression and immunocytochemical studies provide evidence for a prominent activation of both the innate and adaptive immune system in GNT [57,75,76]. In particular, a prominent expression of components of the interleukin (IL)-1/Toll-like receptor (TLR) signaling and complement cascade has been observed in GNT [57,77].…”

“…In particular, a prominent expression of components of the interleukin (IL)-1/Toll-like receptor (TLR) signaling and complement cascade has been observed in GNT [57,77]. Recent findings indicate a prominent upregulation of major histocompatibility complex class I (MHC-I) in neuronal cells as part of the immune response occurring in different epileptogenic glioneuronal lesions characterized by mTOR pathway activation (GG, FCD, and TSC; [76]).…”

MR Imaging–Based Correction for Partial Volume Effect Improves Detectability of Intractable Epileptogenic Foci on Iodine 123 Iomazenil Brain SPECT Images: An Extended Study with a Larger Sample Size

“…18 The case of subcortical heterotopia indicated in Fig 3C is thought to be a representative example. In cases of tumor, underexpressed GABA-receptor signaling in gangliogliomas, 19 (GABA)A-central low benzodiazepine receptor binding in dysembryoplastic neuroepithelial tumors, 20 or a significant decrease in GABAergic-immunoreactive neurons in low-grade gliomas 21 has been reported. As a result of tumor cell proliferation, regional gray matter concentration in the foci is naturally increased in cases of tumor.…”