Morphological alterations of the neuronal Golgi apparatus upon seizures.

AIMS: Epilepsy is one of the most common chronic neurological disorders, affecting around 50 million people worldwide, but its underlying cellular and molecular events are not fully understood. The Golgi is a highly dynamic cellular organelle and can be fragmented into ministacks under both physiological and pathological conditions. This phenomenon has also been observed in several neurodegenerative disorders; however, the structure of the Golgi apparatus (GA) in human patients suffering from epilepsy has not been described so far. The aim of this study was to assess the changes in GA architecture in epilepsy. METHODS: Golgi visualisation with immunohistochemical staining in the neocortex of adult patients who underwent epilepsy surgery; 3D reconstruction and quantitative morphometric analysis of GA structure in the rat hippocampi upon kainic acid (KA) induced seizures, as well as in vitro studies with the use of Ca2+ chelator BAPTA-AM in primary hippocampal neurons upon activation were performed. RESULTS: We observed GA dispersion in neurons of the human neocortex of patients with epilepsy and hippocampal neurons in rats upon KA-induced seizures. The structural changes of GA were reversible, as GA morphology returned to normal within 24 h of KA treatment. KA-induced Golgi fragmentation observed in primary hippocampal neurons cultured in vitro was largely abolished by the addition of BAPTA-AM. CONCLUSIONS: In our study, we have shown for the first time that the neuronal GA is fragmented in the human brain of patients with epilepsy and rat brain upon seizures. We have shown that seizure-induced GA dispersion can be reversible, suggesting that enhanced neuronal activity induces Golgi reorganisation that is involved in aberrant neuronal plasticity processes that underlie epilepsy. Moreover, our results revealed that elevated cytosolic Ca2+ is indispensable for these KA-induced morphological alterations of GA in vitro.

Epigenetic Downregulation of Hsa-miR-193b-3p Increases Cyclin D1 Expression Level and Cell Proliferation in Human Meningiomas.

Meningiomas are common intracranial tumors in adults. Abnormal microRNA (miRNA) expression plays a role in their pathogenesis. Change in miRNA expression level can be caused by impaired epigenetic regulation of miRNA-encoding genes. We found the genomic region covering the MIR193B gene to be DNA hypermethylated in meningiomas based on analysis of genome-wide methylation (HumanMethylation450K Illumina arrays). Hypermethylation of MIR193B was also confirmed via bisulfite pyrosequencing. Both hsa-miR-193b-3p and hsa-miR-193b-5p are downregulated in meningiomas. Lower expression of hsa-miR-193b-3p and higher MIR193B methylation was observed in World Health Organization (WHO) grade (G) II/III tumors as compared to GI meningiomas. CCND1 mRNA was identified as a target of hsa-miR-193b-3p as further validated using luciferase reporter assay in IOMM-Lee meningioma cells. IOMM-Lee cells transfected with hsa-miR-193b-3p mimic showed a decreased cyclin D1 level and lower cell viability and proliferation, confirming the suppressive nature of this miRNA. Cyclin D1 protein expression (immunoreactivity) was higher in atypical than in benign meningiomas, accordingly to observations of lower hsa-miR-193b-3p levels in GII tumors. The commonly observed hypermethylation of MIR193B in meningiomas apparently contributes to the downregulation of hsa-miR-193b-3p. Since hsa-miR-193b-3p regulates proliferation of meningioma cells through negative regulation of cyclin D1 expression, it seems to be an important tumor suppressor in meningiomas.

Chordoma and meningioma arising as a collision tumor in the petroclival region: Case report and literature review.

INTRODUCTION: The co-existence of two independent brain tumors at the same anatomical site is rare and occurs as a "collision tumor" or "tumor-to-tumor metastasis." In intracranial location, meningioma is the most common neoplasm in such coincidences. CASE DESCRIPTION: We present a case involving a 31-year-old woman with a complex tumor consisting of chordoma and meningioma in the petroclival region. The patient presented with left facial numbness, ataxia, and left-sided hemiparesis. Computed tomography and magnetic resonance imaging showed a well-demarcated, intradural, extra-axial tumor mass in the petroclival region. After complete total resection, histopathological examination revealed two different parts of the tumor, consisting of chordoma and meningioma. Therefore, additional radiation therapy and adjuvant chemotherapy were given. DISCUSSION: To the best of our knowledge, this is the first description of the simultaneous occurrence of chordoma and meningioma in the same anatomical location. In such a scenario, differential diagnosis of choroid meningioma and chordoma is required. The correct recognition of both components is important for treating this complex tumor, and its separate elements may require independent approaches.

Trigone ventricular meningiomas - clinical characteristics, histopathology and results of surgical treatment.

AIM OF THE STUDY: Intraventricular meningiomas (IVMs) are rare tumours accounting for 0.5-3.0% of all meningiomas. IVMs require different surgical approaches and preparation in deep brain areas. The aim of our study was to present the clinico- -histopathological characteristics and treatment outcomes of trigone IVMs in a series of 15 patients. MATERIALS AND METHODS: Eight women and seven men (mean age 52) with 15 trigone IVMs were retrospectively analysed. Patients presented with headache (47%), psychoorganic syndrome (40%), hemianopsia (33%) or paresis (20%), including three (20%) patients with Karnofsky Performance Scale (KPS) < 80. Mean tumour size was 55.2 mm (range: 30-100 mm). RESULTS: Gross total tumour resection was performed in 14 (93%) cases, and subtotal in one (7%). A new deficit appeared in 83% (5/6) following a transparietal approach, in 14% (1/7) following a transtemporal approach, and in none of two patients following a transoccipital approach. Postoperative complications occurred in six (40%) patients; no patient died, but in two (13%) the new deficit was permanent. Tumour re-growth was found in two (13%) patients after 14 and 31 months. Meningiomas of WHO grade I occurred in 12, grade II in three, and grade III in one tumour recurrence. In long-term follow-up (mean: 60.8 months), including the results of revision operations, KPS: 80-100 was in 13 (87%) patients, KPS: 50 in one (severe hemiparesis after revision) and one patient was lost to follow-up (KPS: 100 on discharge). CONCLUSIONS: 20% of IVMs in our series were atypical. The results of surgery for IVMs, although satisfactory in general, require further improvement by reducing the rate of focal deficits resulting from a surgical approach.

Medulloblastoma with transitional features between Group 3 and Group 4 is associated with good prognosis.

Medulloblastoma, the most common malignant pediatric brain tumor, is a heterogeneous disease, with the existence of at least four molecular types: Wingless (WNT), Sonic Hedgehog (SHH), Group 3 and Group 4 tumors. The latter two groups, which can be identified by an application of multi-gene expression or methylation profiling, show sometimes ambiguous categorization and are still classified for diagnostic reason as non-SHH/non-WNT medulloblastomas in updated WHO 2016 classification. In order to better characterize non-SHH/non-WNT tumors, we applied the method based on the Nanostring nCounter Technology, using the 26 genes codeset in 68 uniformly treated medulloblastoma patients. This allowed for identification of tumors, which shared common Group 3 and Group 4 gene signatures. We recognized three transcriptional groups within non-WNT/non-SHH tumors: Group 3, Group 4 and the Intermediate 3/4 Group. Group 3, in line with previously published results, showed poor prognosis with survival rate < 40%, frequent metastases, large cell/anaplastic pathology and presence of tumors with MYCC amplification. This is in contrast to patients from the Intermediate 3/4 Group who showed the best survival rate (100%). Overall and progression free survival were better for this group than for Group 3 (p = 0.001, for both) and Group 4 (p = 0.064 and p = 0.066, respectively). Our work supports the view that within the non-WNT/non-SHH tumors different risk groups exist and that the current two groups classifier may be not sufficient for proper clinical categorization of individual patients.

Contrast enhancement pattern predicts poor survival for patients with non-WNT/SHH medulloblastoma tumours.

Recent studies revealed the biological heterogeneity of medulloblastoma, with the existence of at least four groups which are associated with several clinical and morphological features. We investigated for further correlations between molecular types, location of tumours, their contrast enhancement pattern and survival of patients. Altogether 76 tumours were analyzed and molecular subtypes were identified by immunohistochemistry using representative antibodies, detection of chromosome 6 monosomy and CTNNB1 mutation. The site of the tumour was assessed on diagnosis using Magnetic Resonance images and intra-operative surgical reports. In addition, the gadolinium enhancement pattern was also investigated in pre-treatment tumours. Cerebellar hemispheric location was associated with SHH tumours (p < 0.001), as opposed to midline location being typical for WNT and non-WNT/SHH tumours. Remarkably, for patients with non-WNT/SHH tumours, the extensive gadolinium enhancement pattern (present in >75% of tumour volume) predicted worse OS and EFS than for those with none/weak or heterogeneous enhancement (>10-75% of tumour volume), (both p < 0.001). Our analysis indicates that distribution of the medulloblastoma tumours location is related to the biological characteristics of tumour. Importantly, the enhancement pattern of the tumour may be a clinically useful prognostic marker for patients with non-WNT/SHH medulloblastomas.

Papillary glioneuronal tumor with an unusual bilateral intraventricular localization.

Papillary glioneuronal tumor (PGNT) is a rare brain tumor (World Health Organization grade I) with a glioneuronal dual nature. It has a characteristic morphological pattern composed of astroglial pseudopapillary structures and interpapillary neurocytic elements. The tumor usually occurs in the supratentorial region in children and young adults, with a predilection for the temporal lobe. It is typically localized within the deep white matter adjacent to the lateral ventricles and rarely invades the ventricular cavities. Predominantly intraventricular localization of PGNT is uncommon. We report our experience with a PGNT that was bilaterally localized within the lateral ventricles of a 27-year-old woman. Magnetic resonance imaging demonstrated a solid, partially cystic mass in the left and right lateral ventricles. Part of the tumor was removed by surgery, followed by radiation therapy. Histopathological studies revealed typical pseudopapillary structures, created by glial fibrillary acidic protein (GFAP)-immunopositive cells, arranged around hyalinized blood vessels. The interpapillary component was composed of small, uniform, neurocyte-like cells with strong synaptophysin reactivity. Mitoses were rare, and necrosis was absent. The MIB-1 labeling index was low. The tumor was diagnosed as a PGNT. To our knowledge, this is the only report of this rare entity being located bilaterally in both cavities of the lateral ventricles.

Alternative splicing of iodothyronine deiodinases in pituitary adenomas. Regulation by oncoprotein SF2/ASF.

Pituitary tumors belong to the group of most common neoplasms of the sellar region. Iodothyronine deiodinase types 1 (DIO1) and 2 (DIO2) are enzymes contributing to the levels of locally synthesized T3, a hormone regulating key physiological processes in the pituitary, including its development, cellular proliferation, and hormone secretion. Previous studies revealed that the expression of deiodinases in pituitary tumors is variable and, moreover, there is no correlation between mRNA and protein products of the particular gene, suggesting the potential role of posttranscriptional regulatory mechanisms. In this work we hypothesized that one of such mechanisms could be the alternative splicing. Therefore, we analyzed expression and sequences of DIO1 and DIO2 splicing variants in 30 pituitary adenomas and 9 non-tumorous pituitary samples. DIO2 mRNA was expressed as only two mRNA isoforms. In contrast, nine splice variants of DIO1 were identified. Among them, five were devoid of exon 3. In silico sequence analysis of DIO1 revealed multiple putative binding sites for splicing factor SF2/ASF, of which the top-ranked sites were located in exon 3. Silencing of SF2/ASF in pituitary tumor GH3 cells resulted in change of ratio between DIO1 isoforms with or without exon 3, favoring the expression of variants without exon 3. The expression of SF2/ASF mRNA in pituitary tumors was increased when compared with non-neoplastic control samples. In conclusion, we provide a new mechanism of posttranscriptional regulation of DIO1 and show deregulation of DIO1 expression in pituitary adenoma, possibly resulting from disturbed expression of SF2/ASF.

A peculiar histopathological form of dysembryoplastic neuroepithelial tumor with separated pilocytic astrocytoma and rosette-forming glioneuronal tumor components.

Dysembryoplastic neuroepithelial tumors (DNTs) mostly display typical clinical, neuroimaging and histopathological features, but sometimes they reveal heterogeneous or non-specific morphology, which results in diagnostic dilemmas. We present a case of a young adult with longstanding, intractable epilepsy associated with a multinodular cystic lesion in the temporal lobe. The lesion consisted of morphologically different components. In particular, a few cortical nodules displayed a specific glioneuronal element with floating neurons typically found in DNT. Two large, well-circumscribed nodules were entirely composed of biphasic, piloid, astroglial patterns that corresponded strictly to a pilocytic astrocytoma. The well-defined areas, which contained numerous distinct neurocytic-like rosettes, were identical with rosette-forming glioneuronal tumors (RGNTs). This type of neurocytic rosette was widespread within the surrounding piloid background. Some solid nodules exhibited increased cellularity, oligodendroglioma-like elements and a focal ribbon cell arrangement. The lesion was associated with advanced reactive gliosis and foci of dysplastic changes in the adjacent cortex. The clinico-radiological and main histopathological features were consistent with a diagnosis of a complex variant of DNT composed of pilocytic and rosette-forming glioneuronal components. Although both piloid tissue and rosette-like formations have been occasionally mentioned in DNT lesions, the present case of DNT was unique in its well-circumscribed, separate pilocytic and RGNT nodules. We concluded that it represented an unusual, mixed pilocytic/RGNT variant of DNT.

Giant cell glioblastoma with unique bilateral cerebellopontine angle localization considered as extraaxial tumor growth in a patient with neurofibromatosis Type 1.

Giant cell glioblastoma multiforme (GCGBM) is a rare variant of glioblastoma, occurring predominantly in the cerebral hemispheres. Its infratentorial localization has been documented occasionally, while GCGBM in the cerebellopontine angle (CPA) region has not been described so far. We report a case of GCGBM presenting primarily as an extraaxial bilateral CPA tumor in a 29-year-old woman with neurofibromatosis Type 1 (NF1). The patient died shortly after surgery of the right CPA tumor. Postmortem study of the brain revealed large tumor masses, located in the CPA bilaterally, encasing the brainstem base and cisternal portions of the cranial nerves. Tumor masses were demarcated from the brainstem and cerebellum and covered by leptomeninges. Microscopically, a slight subpial tumor seeding from the leptomeninges into the brain parenchyma was observed in the right CPA region. The tumor showed highly pleomorphic, giant and multinucleated cells, densely cellular sheets of poorly differentiated cells and pseudopalisading necroses. Tumor cells were positive for GFAP, S-100 protein, and p53 and negative for neuronal antigens. The MIB-1 labeling index was very high in densely cellular areas. To our knowledge this is the second report of GCGBM in an NF1 patient and the first reported case of GCGBM presenting as an extraaxial leptomeningeal lesion with bilateral CPA localization, which might be considered as primary leptomeningeal gliomatosis.

BCOR expression in paediatric pineoblastoma.

BCOR is expressed in a new brain tumour entity, i.e. 'CNS tumour with BCOR internal tandem duplication' (HGNET BCOR) but not in several other high grade paediatric brain tumours investigated. Immunohistochemical detection of BCOR expression may therefore serve as a potential diagnostic marker. Nevertheless, in rare paediatric glioma cases recurrent EP300-BCOR fusions were detected, which resulted in strong BCOR immunopositivity. We have therefore examined other, not analysed so far, types of central nervous system (CNS) tumours, pineoblastoma and germinoma, to assess a potential involvement of BCOR in these tumours. Levels of BCOR RNA expression were investigated by NanoString nCounter system analysis in a series of altogether 66 high grade paediatric tumours, including four pineoblastoma cases. Immunohistological detection of BCOR was performed in eight pineoblastoma, five germinoma and four atypical teratoid rhabdoid tumours (ATRTs), all located in the pineal region. We detected BCOR expression in all pineoblastomas, at the RNA and protein levels, but not in germinomas and ATRTs. Further analysis of pineoblastoma samples did not reveal the presence of either BCOR internal tandem duplication or BCOR fusion involvement. Positive immunohistological BCOR nuclear reaction in pineoblastoma may therefore differentiate this type of tumour from other high grade tumours located in the pineal region.

[Post-polio syndrome. Part I. The "legacy" of forgotten disease, challenges for professionals and polio survivors]. / Zespól post-polio. Czesc I. "Dziedzictwo" zapomnianej choroby, wyzwanie dla lekarzy i pacjentów

The outcome of paralytic polio was believed to be a stable neurological state. Now, it is established that polio has an additional, slowly progressive phase, called post-polio syndrome (PPS) that develops 30-40 years after the acute poliomyelitis in 25-80% of paralytic and about 40% of nonparalytic polio survivors. The clinical symptoms are nonspecific and usually include muscle weakness, fatigue and muscle or joint pain. Some patients suffer from muscular atrophy, respiratory insufficiency, dysphagia, sleep disturbances or cold intolerance. The etiopathogenesis of PPS is unclear and many factors, such as dysfunction of the surviving motor units, aging, defects of neuromuscular transmission, persistence of viral infection and immunological mechanisms, are considered.

[Post-polio syndrome. Part II. Therapeutic management]. / Zespól post-polio. Czesc II. Postepowanie terapeutyczne.

The care of patients with post-polio syndrome ought to be carried out by a multidisciplinary team of specialists, including medical professionals, specialists of rehabilitation, psychologists and social workers. Many therapeutic strategies might be employed to reduce the late effects of polio. Today, the management of post-polio syndrome is based on non-pharmacological intervention, including lifestyle modification, decrease of physical activity, rest periods during the day and an individually tailored training program.

Radiation-induced tumours of meninges. Report on eight cases and review of the literature.

BACKGROUND AND PURPOSE: Despite their rarity, post-radiation meningeal tumours seem to be a growing problem due to the increasing application of radiation therapy. The aim of the study was to ascertain the specific features of these tumours. MATERIAL AND METHODS: Among 433 intracranial meningeal tumours treated from 2000 to 2008, eight cases (2%) have been presumed to be associated with high-dose therapeutic radiation for previous neoplasm of the head (7) or neck (1). On average, tumours were diagnosed 24 years after irradiation. All patients had a solitary meningeal tumour, but two of them also developed other neoplasms in the irradiated area. RESULTS: All tumours were microsurgically removed. The post-operative course was uncomplicated in two cases only. In the remaining 6 (75%), complications included liquorrhoea (2), brain oedema (1), venous thrombosis (1), bleeding into the tumour bed (1) and focal deficit due to manipulation (3). Most tumours (5) were WHO grade I meningiomas. These benign meningiomas exhibited some peculiar histological features, including focal increase of cellularity, focal enhancement of proliferation index, pleomorphism of nuclei, occasional mitotic figures and, in one case, evidence of brain invasion. One meningioma was assigned to WHO grade II, one to WHO grade III and one appeared to be meningeal fibrosarcoma. The event-free survival and overall survival rate at 4.4 years of follow-up were 63% and 75%, respectively. CONCLUSIONS: Radiation-induced tumours of the meninges show certain characteristic histopathological features, which may promote invasiveness of the tumour and higher risk of malignancy.

Proteasome and Neuroprotective Effect of Hyperbaric Oxygen Preconditioning in Experimental Global Cerebral Ischemia in Rats.

OBJECTIVES: We investigated the involvement of the proteasome in the mechanism of preconditioning with hyperbaric oxygen (HBO-PC). METHODS: The experiments were performed on male Wistar rats subjected to a transient global cerebral ischemia of 5 min duration (2-vessel occlusion model) and preconditioned or not with HBO for 5 preceding days (1 h HBO at 2.5 atmosphere absolute [ATA] daily). In subgroups of preconditioned rats, the proteasome inhibitor MG132 was administered 30 min prior to each preconditioning session. Twenty-four hours and 7 days post-ischemia, after neurobehavioral assessment, the brains were collected and evaluated for morphological changes and quantitative immunohistochemistry of cell markers and apoptosis-related proteins. RESULTS: We observed reduced damage of CA1 pyramidal cells in the HBO preconditioned group only at 7 days post-ischemia. However, both at early (24 h) and later (7 days) time points, HBO-PC enhanced the tissue expression of 20S core particle of the proteasome and of the nestin, diminished astroglial reactivity, and reduced p53, rabbit anti-p53 upregulated modulator of apoptosis (PUMA), and rabbit anti-B cell lymphoma-2 interacting mediator of cell death (Bim) expressions in the hippocampus and cerebral cortex. HBO-PC also improved T-maze performance at 7 days. Proteasome inhibitor abolished the beneficial effects of HBO-PC on post-ischemic neuronal injury and functional impairment and reduced the ischemic alterations in the expression of investigated proteins. SIGNIFICANCE: Preconditioning with hyperbaric oxygen-induced brain protection against severe ischemic brain insult appears to involve the proteasome, which can be linked to a depletion of apoptotic proteins and improved regenerative potential.

Rosette-forming glioneuronal tumor of the fourth ventricle with advanced microvascular proliferation--a case report.

Rosette-forming glioneuronal tumor (RGNT) of the fourth ventricle is a recently described novel type of primary brain tumor that was included into the current WHO classification of CNS tumors. It is a very rare, slowly growing, mixed neoplasm at cerebellar localization with distinctive morphological pattern. We present an unusual case of a 20-year-old patient with RNGT of the fourth ventricle with advanced microvascular proliferation. MRI revealed the solid-cystic tumor mass largely involving the cerebellar vermis and left hemisphere with compression of the fourth ventricle. Microscopically, the tumor showed classical architectural pattern with two distinctive components. The main component consisted of neurocytic rosettes formed by round, isomorphic nuclei arranged around eosinophilic, fibrillar cores with strong synaptophysin expression. The perivascular rosettes with cell arrangement along blood vessels were observed only sporadically. The second neoplastic component consisted of spindle or stellate astroglial cells with piloid process and Rosenthal fibers, strongly resembling pilocytic astrocytoma. Focally, the astroglial cells showed increased cellularity but without marked nuclear atypia. The glial part of the tumor revealed advanced proliferation of microvessels. The vessels of glomeruloid type exhibited multilayered endothelial proliferation and marked mitotic activity. MIB1 labelling index was generally low; however, in areas exhibiting microvascular proliferation its expression was significantly increased up to 20%. This report demonstrates the unique case of RGNT with conspicuous microvascular proliferation of glomeruloid type and extensive endothelial proliferation. As there is still limited clinical experience with RGNT, further studies are necessary to evaluate the biology of this type of tumor.

Transcriptional profiling of paediatric ependymomas identifies prognostically significant groups.

The majority of supratentorial ependymomas in children contain oncogenic fusions, such as ZFTA-RELA or YAP1-MAMLD1. In contrast, posterior fossa (PF) ependymomas lack recurrent somatic mutations and are classified based on gene expression or methylation profiling into group A (PFA) and group B (PFB). We have applied a novel method, NanoString nCounter Technology, to identify four molecular groups among 16 supratentorial and 50 PF paediatric ependymomas, using 4-5 group-specific signature genes. Clustering analysis of 16 supratentorial ependymomas revealed 9 tumours with a RELA fusion-positive signature (RELA+), 1 tumour with a YAP1 fusion-positive signature (YAP1+), and 6 not-classified tumours. Additionally, we identified one RELA+ tumour among historically diagnosed CNS primitive neuroectodermal tumour samples. Overall, 9 of 10 tumours with the RELA+ signature possessed the ZFTA-RELA fusion as detected by next-generation sequencing (p = 0.005). Similarly, the only tumour with a YAP1+ signature exhibited the YAP1-MAMLD1 fusion. Among the remaining unclassified ependymomas, which did not exhibit the ZFTA-RELA fusion, the ZFTA-MAML2 fusion was detected in one case. Notably, among nine ependymoma patients with the RELA+ signature, eight survived at least 5 years after diagnosis. Clustering analysis of PF tumours revealed 42 samples with PFA signatures and 7 samples with PFB signatures. Clinical characteristics of patients with PFA and PFB ependymomas corroborated the previous findings. In conclusion, we confirm here that the NanoString method is a useful single tool for the diagnosis of all four main molecular groups of ependymoma. The differences in reported survival rates warrant further clinical investigation of patients with the ZFTA-RELA fusion.

Morphological and ultrastructural changes in Herpes simplex encephalomyelitis: an attempt to determinate the etiological factor.

Herpes simplex encephalomyelitis (HSE) is a rare disease with a high mortality rate. Correct diagnosis is established on the basis of the combination of the clinical and investigative features. Unfortunately, precise diagnosis remains difficult due to several clinical similarities and false negative or inconclusive results of diagnostic tests. Here, we present two cases of HSE together with the morphological and ultrastructural picture. The first case was a 45-year-old man with acute symptoms of encephalitis, and the other one was a 28-year-old woman presenting subacute encephalomyelitis. Both cases had negative serologic and molecular results for Herpes simplex in the blood and cerebrospinal fluid. Brain and spinal cord samples taken from both cases were stained typically with histological and immunohistochemical methods and small tissue fragments were examined with the transmission electron microscope (TEM). Microscopic examination confirmed viral encephalomyelitis in both cases. An electron micrograph showed typical intranuclear viral particles inside of damaged neurons, which together with topography of brain and spinal cord changes suggest HHV-1/HHV-2 in the first case and/or HHV-3 in the other case. Thus, morphological and ultrastructural examinations may be a useful tool to set up correct diagnosis and help to determine the pathogenic factor in patients suspected of viral encephalomyelitis.

Molecular identification of CNS NB-FOXR2, CNS EFT-CIC, CNS HGNET-MN1 and CNS HGNET-BCOR pediatric brain tumors using tumor-specific signature genes.

Four molecular types of rare central nervous system (CNS) tumors have been recently identified by gene methylation profiling: CNS Neuroblastoma with FOXR2 activation (CNS NB-FOXR2), CNS Ewing Sarcoma Family Tumor with CIC alteration (CNS EFT-CIC), CNS high grade neuroepithelial tumor with MN1 alteration (CNS HGNET-MN1) and CNS high grade neuroepithelial tumor with BCOR alteration (CNS HGNET-BCOR). Although they are not represented in 2016 updated WHO classification of CNS tumors, their diagnostic recognition is important because of clinical consequences. We have introduced a diagnostic method based on transcription profiling of tumor specific signature genes from formalin-fixed, paraffin-embedded tumor blocks using NanoString nCounter Technology. Altogether, 14 out of 187 (7.4%) high grade pediatric brain tumors were diagnosed with either of four new CNS categories. Histopathological examination of the tumors confirmed, that they demonstrate a spectrum of morphology mimicking other CNS high grade tumors. However, they also exhibit some suggestive histopathological and immunohistochemical features that allow for a presumptive diagnosis prior to molecular assessment. Clinical characteristics of patients corroborated with the previous findings for CNS EFT-CIC, CNS NB-FOXR2 and CNS HGNET-MN1 patients, with a favorable survival rate for the latter two groups. Among six CNS HGNET-BCOR patients, three patients are long term survivors, suggesting possible heterogeneity within this molecular category of tumors. In summary, we confirmed the effectiveness of NanoString method using a single, multi-gene tumor specific signature and recommend this novel approach for identification of either one of the four newly described CNS tumor entities.

Transfection with liver-type glutaminase cDNA alters gene expression and reduces survival, migration and proliferation of T98G glioma cells.

Liver-type glutaminase (LGA) is a glutaminase isoform that has been implicated in transcription modulation. LGA mRNA is absent from postoperative samples of primary gliomas and is low in cultured astrocytes. In this study, stable transfection of T98G cells with a vector carrying human LGA sequence increased the expression of LGA mRNA and protein, and the ability of the cells to degrade glutamine (Gln), as manifested by a three-fold reduction of their steady-state Gln content and a 2.5-fold increase of their glutamate (Glu) content. The transfected cells (TLGA cells) showed a 40% decrease of cell survival as assessed by colony formation, well correlated with significant reduction of mitochondrial activity as demonstrated with MTT test. Also, a 45% reduction of cell migration and a 47% decrease of proliferation index (Ki67 immunostaining) were found as compared with sham-transfected cells. Microarray analysis, which included over 47,000 transcripts, revealed a significantly altered expression of 85 genes in TLGA, but not in sham-transfected or control cells (P < 0.005). Microarray data were confirmed with real-time PCR analysis for eight genes potentially relevant to malignancy: S100A16, CAPN2, FNDC3B, DYNC1LI1, TIMP4, MGMT, ADM, and TIMP1. Of these changes, decreased expression of S100A16 and MGMT can be best reconciled with the current views on the role of their protein products in glioma malignancy. Malignancy-reducing effect of newly inserted LGA mRNA in glioblastoma cells can be reconciled with a hypothesis that absence of such a modulatory mechanism in glia-derived tumors deprived of LGA mRNA may facilitate some aspects of their progression.