Browsing by Author "Pamir, M. Necmettin"

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Analysis of Mitochondrial DNA Control Region D-Loop in Gliomas: Result of 52 Patients
(TURKISH NEUROSURGICAL SOC, 2021-01-01) Yuksel, Sirin Kilicturgay; Ozduman, Koray; Yilmaz, Engin; Pamir, M. Necmettin; Akyerli, Cemaliye B.
AIM: To investigate the effect of mitochondrial DNA (mtDNA) variants mainly in D-loop on glioma biology. MATERIAL and METHODS: Sanger sequencing of D-loop (15971-16451 bp) for 52 glioma patients was performed and the variations were statistically analyzed for gender, WHO classification, morphological grade, IDH/TERT status. RESULTS: Total of 122 variations (51 unique) were identified in 52 patients. C16223T, T16189C, T16311C and T16126C variants were frequently detected. The total variation number was statistically non-significant among the analyzed categories. When individual variants were considered, T16311C and T16224C were statistically significant for WHO classification (p=0.033), morphological grade (p=0.036) and gender (p=0.039), respectively. CONCLUSION: Total variation number in D-loop was not found to be related with clinical variables. Our data suggests that individual variants may play a critical role in glioma biology.
Associations of meningioma molecular subgroup and tumor recurrence
(OXFORD UNIV PRESS INC, 2021-01-01) Youngblood, Mark W.; Miyagishima, Danielle F.; Jin, Lan; Gupte, Trisha; Li, Chang; Duran, Daniel; Montejo, Julio D.; Zhao, Amy; Sheth, Amar; Tyrtova, Evgeniya; Ozduman, Koray; Iacoangeli, Francesco; Peyre, Matthieu; Boetto, Julien; Pease, Matthew; Avsar, Timucin; Huttner, Anita; Bilguvar, Kaya; Kilic, Turker; Pamir, M. Necmettin; Amankulor, Nduka; Kalamarides, Michel; Erson-Omay, E. Zeynep; Gunel, Murat; Moliterno, Jennifer
Background. We and others have identified mutually exclusive molecular subgroups of meningiomas
Chordoma: Immunohistochemical Analysis of Brachury
(TURKISH NEUROSURGICAL SOC, 2018-01-01) Sun, H. Ibrahim; Guduk, Mustafa; Gucyetmez, Bulent; Yapicier, Ozlem; Pamir, M. Necmettin
AIM: Chordomas are rare, slow growing but locally aggressive malignancies of the axial skeleton. Skull base chordomas, due to their intricate anatomical localization, pose significant challenges to managing physicians. In classical and chondroid chordomas, the disease course cannot be reliably determined using only morphological criteria. Brachyury (T Gene) was shown to play a central role in chordoma pathogenesis and several studies also showed that this gene also carries potential as a prognostic biomarker. This study aims to correlate Brachyury expression with the clinical course in surgically treated skull base chordomas. MATERIAL and METHODS: Chordoma tumor samples from 14 patients with skull base chordomas, diagnosed using histopathological and immunohistochemistry criteria (epithelial membrane antigen (EMA), S100, pan cytokeratin (panCK)) were retrospectively analyzed for Brachyury expression using immunohistochemistry. Brachyury expression was graded using a 4 point semi-quantitative scoring system. Focal (grade II) and diffuse staining (grade III) were considered as overexpression. Patient recurrence-free survival and total survival were compared between Brachyury overexpressing and non-overexpressing groups using Kaplan-Meier survival analysis. RESULTS: Among the stained tumor samples, 85.7\% were positive for brachyury expression. In both groups, there was one sample that was negative. We did not observe any significant difference among the groups for staining, grade and percentage of brachyury positive cells. CONCLUSION: Brachyury expression in tumor samples is not a sensitive indicator of prognosis in chordomas.
Clinical Proton MR Spectroscopy in Central Nervous System Disorders
(RADIOLOGICAL SOC NORTH AMERICA, 2014-01-01) Gulin, O. Z.; Alger, Jeffry R.; Barker, Peter B.; Bartha, Robert; Bizzi, Alberto; Boesch, Chris; Bolan, Patrick J.; Brindle, Kevin M.; Cudalbu, Cristina; Dincer, Alp; Dydak, Ulrike; Emir, Uzay E.; Frahm, Jens; Gonzalez, Ramon Gilberto; Gruber, Stephan; Gruetter, Rolf; Gupta, Rakesh K.; Heerschap, Arend; Henning, Anke; Hetherington, Hoby P.; Howe, Franklyn A.; Hueppi, Petra S.; Hurd, Ralph E.; Kantarci, Kejal; Klomp, Dennis W. J.; Kreis, Roland; Kruiskamp, Marijn J.; Leach, Martin O.; Lin, Alexander P.; Luijten, Peter R.; Marjanska, Malgorzata; Maudsley, Andrew A.; Meyerhoff, Dieter J.; Mountford, Carolyn E.; Nelson, Sarah J.; Pamir, M. Necmettin; Pan, Jullie W.; Peet, Andrew C.; Poptani, Harish; Posse, Stefan; Pouwels, Petra J. W.; Ratai, Eva-Maria; Ross, Brian D.; Scheenen, Tom W. J.; Schuster, Christian; Smith, Ian C. P.; Soher, Brian J.; Tkac, Ivan; Vigneron, Daniel B.; Kauppinen, Risto A.; Grp, M.R.S. Consensus
A large body of published work shows that proton (hydrogen 1 {[}H-1]) magnetic resonance (MR) spectroscopy has evolved from a research tool into a clinical neuroimaging modality. Herein, the authors present a summary of brain disorders in which MR spectroscopy has an impact on patient management, together with a critical consideration of common data acquisition and processing procedures. The article documents the impact of 1H MR spectroscopy in the clinical evaluation of disorders of the central nervous system. The clinical usefulness of 1H MR spectroscopy has been established for brain neoplasms, neonatal and pediatric disorders (hypoxia-ischemia, inherited metabolic diseases, and traumatic brain injury), demyelinating disorders, and infectious brain lesions. The growing list of disorders for which 1H MR spectroscopy may contribute to patient management extends to neurodegenerative diseases, epilepsy, and stroke. To facilitate expanded clinical acceptance and standardization of MR spectroscopy methodology, guidelines are provided for data acquisition and analysis, quality assessment, and interpretation. Finally, the authors offer recommendations to expedite the use of robust MR spectroscopy methodology in the clinical setting, including incorporation of technical advances on clinical units. (c) RSNA, 2014
Correlation of anatomical involvement patterns of insular gliomas with subnetworks of the limbic system
(AMER ASSOC NEUROLOGICAL SURGEONS, 2022-01-01) Ulgen, Ege; Aras, Fuat Kaan; Cosgun, Erdal; Ersen-Danyeli, Ayca; Dincer, Alp; Usseli, M. Imre; Ozduman, Koray; Pamir, M. Necmettin
OBJECTIVE Gliomas frequently involve the insula both primarily and secondarily by invasion. Despite the high connectivity of the human insula, gliomas do not spread randomly to or from the insula but follow stereotypical anatomical involvement patterns. In the majority of cases, these patterns correspond to the intrinsic connectivity of the limbic system, except for tumors with aggressive biology. On the basis of these observations, the authors hypothesized that these different involvement patterns may be correlated with distinct outcomes and analyzed these correlations in an institutional cohort. METHODS Fifty-nine patients who had undergone surgery for insular diffuse gliomas and had complete demographic, pre- and postoperative imaging, pathology, molecular genetics, and clinical follow-up data were included in the analysis (median age 37 years, range 21-71 years, M/F ratio 1.68). Patients with gliomatosis and those with only minor involvement of the insula were excluded. The presence of T2-hyperintense tumor infiltration was evaluated in 12 anatomical structures. Hierarchical biclustering was used to identify co-involved structures, and the findings were correlated with established functional anatomy knowledge. Overall survival was evaluated using Kaplan-Meier and Cox proportional hazards regression analysis (17 parameters). RESULTS The tumors involved the anterior insula (98.3\%), posterior insula (67.8\%), temporal operculum (47.5\%), amygdala (42.4\%), frontal operculum (40.7\%), temporal pole (39\%), parolfactory area (35.6\%), hypothalamus (23.7\%), hippocampus (16.9\%), thalamus (6.8\%), striatum (5.1\%), and cingulate gyrus (3.4\%). A mean 4.2 +/- 2.6 structures were involved. On the basis of hierarchical biclustering, 7 involvement patterns were identified and correlated with cortical functional anatomy (pure insular {[}11.9\%], olfactocentric {[}15.3\%], olfactoopercular {[}33.9\%], operculoinsular {[}15.3\%], striatoinsular {[}3.4\%], translimbic {[}11.9\%], and multifocal {[}8.5\%] patterns). Cox regression identified hippocampal involvement (p = 0.006) and postoperative tumor volume (p = 0.027) as significant negative independent prognosticators of overall survival and extent of resection (p = 0.015) as a significant positive independent prognosticator. CONCLUSIONS The study findings indicate that insular gliomas primarily involve the olfactocentric limbic girdle and that involvement in the hippocampocentric limbic girdle is associated with a worse prognosis.
Dural Arteriovenöz Fistül (DAVF) Tedavisinde Kombine Yaklaşım: Süperselektif Embolizasyon ve Gamma Knife Radyocerrahisi
(Acıbadem Mehmet Ali Aydınlar Üniversitesi, 2010-07-01) Peker, Selçuk; Yıldız, Mehmet Erdem; Çizmeli, Olcay; Pamir, M. Necmettin
ÖZET Dural arteriovenöz fistüller (DAVF) dural arterler ve venler veya sinüsler ara sındaki anormal vasküler bağlantılardan oluşan lezyonlardır. Çok sayıda fis tül içerebilmeleri ve venöz drenaj paternlerindeki değişiklikler tedavi kara rında güçlüklere neden olabilmektedir. Biz bu yazıda sol eksternal karotid arterin orta meningeal ve oksipital dallarından dolan, önce süperselektif olarak embolize edilen ve 3 ay sonraki kontrolde oksipital besleyicilerinin rekanalize olduğu gözlenen DAVF’ li olguya ikinci kez uyguladığımız kom bine süperselektif embolizasyon artı Gamma Knife tedavisini sunmaktayız.
Genomic Analysis of Non-NF2 Meningiomas Reveals Mutations in TRAF7, KLF4, AKT1, and SMO
(AMER ASSOC ADVANCEMENT SCIENCE, 2013-01-01) Clark, Victoria E.; Erson-Omay, E. Zeynep; Serin, Akdes; Yin, Jun; Cotney, Justin; Oezduman, Koray; Avsar, Timuin; Li, Jie; Murray, Phillip B.; Henegariu, Octavian; Yilmaz, Saliha; Guenel, Jennifer Moliterno; Carrion-Grant, Geneive; Yilmaz, Baran; Grady, Conor; Tanrikulu, Bahattin; Bakircioglu, Mehmet; Kaymakcalan, Hande; Caglayan, Ahmet Okay; Sencar, Leman; Ceyhun, Emre; Atik, A. Fatih; Bayri, Yasar; Bai, Hanwen; Kolb, Luis E.; Hebert, Ryan M.; Omay, S. Bulent; Mishra-Gorur, Ketu; Choi, Murim; Overton, John D.; Holland, Eric C.; Mane, Shrikant; State, Matthew W.; Bilguevar, Kaya; Baehring, Joachim M.; Gutin, Philip H.; Piepmeier, Joseph M.; Vortmeyer, Alexander; Brennan, Cameron W.; Pamir, M. Necmettin; Kilic, Tuerker; Lifton, Richard P.; Noonan, James P.; Yasuno, Katsuhito; Guenel, Murat
We report genomic analysis of 300 meningiomas, the most common primary brain tumors, leading to the discovery of mutations in TRAF7, a proapoptotic E3 ubiquitin ligase, in nearly one-fourth of all meningiomas. Mutations in TRAF7 commonly occurred with a recurrent mutation ( K409Q) in KLF4, a transcription factor known for its role in inducing pluripotency, or with AKT1(E17K), a mutation known to activate the PI3K pathway. SMO mutations, which activate Hedgehog signaling, were identified in similar to 5\% of non-NF2 mutant meningiomas. These non-NF2 meningiomas were clinically distinctive-nearly always benign, with chromosomal stability, and originating from the medial skull base. In contrast, meningiomas with mutant NF2 and/or chromosome 22 loss were more likely to be atypical, showing genomic instability, and localizing to the cerebral and cerebellar hemispheres. Collectively, these findings identify distinct meningioma subtypes, suggesting avenues for targeted therapeutics.
High-resolution Whole-Genome Analysis of Skull Base Chordomas Implicates FHIT Loss in Chordoma Pathogenesis
(NEOPLASIA PRESS, 2012-01-01) Diaz, Roberto Jose; Guduk, Mustafa; Romagnuolo, Rocco; Smith, Christian A.; Northcott, Paul; Shih, David; Berisha, Fitim; Flanagan, Adrienne; Munoz, David G.; Cusimano, Michael D.; Pamir, M. Necmettin; Rutka, James T.
Chordoma is a rare tumor arising in the sacrum, clivus, or vertebrae. It is often not completely resectable and shows a high incidence of recurrence and progression with shortened patient survival and impaired quality of life. Chemo-therapeutic options are limited to investigational therapies at present. Therefore, adjuvant therapy for control of tumor recurrence and progression is of great interest, especially in skull base lesions where complete tumor resection is often not possible because of the proximity of cranial nerves. To understand the extent of genetic instability and associated chromosomal and gene losses or gains in skull base chordoma, we undertook whole-genome single-nucleotide polymorphism microarray analysis of flash frozen surgical chordoma specimens, 21 from the clivus and 1 from C1 to C2 vertebrae. We confirm the presence of a deletion at 9p involving CDKN2A, CDKN2B, and MTAP but at a much lower rate (22\%) than previously reported for sacral chordoma. At a similar frequency (21\%), we found aneuploidy of chromosome 3. Tissue microarray immunohistochemistry demonstrated absent or reduced fragile histidine triad (FHIT) protein expression in 98\% of sacral chordomas and 67\% of skull base chordomas. Our data suggest that chromosome 3 aneuploidy and epigenetic regulation of FHIT contribute to loss of the FHIT tumor suppressor in chordoma. The finding that FHIT is lost in a majority of chordomas provides new insight into chordoma pathogenesis and points to a potential new therapeutic target for this challenging neoplasm. Neoplasia (2012) 14, 788-798
IDH-mutant glioma specific association of rs55705857 located at 8q24.21 involves MYC deregulation
(NATURE PUBLISHING GROUP, 2016-01-01) Oktay, Yavuz; Ulgen, Ege; Can, Ozge; Akyerli, Cemaliye B.; Yuksel, Sirin; Erdemgil, Yigit; Durasi, I. Melis; Henegariu, Octavian Ioan; Nanni, E. Paolo; Selevsek, Nathalie; Grossmann, Jonas; Erson-Omay, E. Zeynep; Bai, Hanwen; Gupta, Manu; Lee, William; Turcan, Sevin; Ozpinar, Aysel; Huse, Jason T.; Sav, M. Aydin; Flanagan, Adrienne; Gunel, Murat; Sezerman, O. Ugur; Yakicier, M. Cengiz; Pamir, M. Necmettin; Ozduman, Koray
The single nucleotide polymorphism rs55705857, located in a non-coding but evolutionarily conserved region at 8q24.21, is strongly associated with IDH-mutant glioma development and was suggested to be a causal variant. However, the molecular mechanism underlying this association has remained unknown. With a case control study in 285 gliomas, 316 healthy controls, 380 systemic cancers, 31 other CNS-tumors, and 120 IDH-mutant cartilaginous tumors, we identified that the association was specific to IDH-mutant gliomas. Odds-ratios were 9.25 (5.17-16.52
Information theory approaches to improve glioma diagnostic workflows in surgical neuropathology
(WILEY, 2022-01-01) Cevik, Lokman; Landrove, Marilyn Vazquez; Aslan, Mehmet Tahir; Khammad, Vasilii; Garagorry Guerra, Francisco Jose; Cabello-Izquierdo, Yolanda; Wang, Wesley; Zhao, Jing; Becker, Aline Paixao; Czeisler, Catherine; Rendeiro, Anne Costa; Sousa Veras, Lucas Luis; Zanon, Maicon Fernando; Reis, Rui Manuel; Matsushita, Marcus de Medeiros; Ozduman, Koray; Pamir, M. Necmettin; Danyeli, Ayca Ersen; Pearce, Thomas; Felicella, Michelle; Eschbacher, Jennifer; Arakaki, Naomi; Martinetto, Horacio; Parwani, Anil; Thomas, Diana L.; Otero, Jose Javier
Aims Resource-strained healthcare ecosystems often struggle with the adoption of the World Health Organization (WHO) recommendations for the classification of central nervous system (CNS) tumors. The generation of robust clinical diagnostic aids and the advancement of simple solutions to inform investment strategies in surgical neuropathology would improve patient care in these settings. Methods We used simple information theory calculations on a brain cancer simulation model and real-world data sets to compare contributions of clinical, histologic, immunohistochemical, and molecular information. An image noise assay was generated to compare the efficiencies of different image segmentation methods in H\&E and Olig2 stained images obtained from digital slides. An auto-adjustable image analysis workflow was generated and compared with neuropathologists for p53 positivity quantification. Finally, the density of extracted features of the nuclei, p53 positivity quantification, and combined ATRX/age feature was used to generate a predictive model for 1p/19q codeletion in IDH-mutant tumors. Results Information theory calculations can be performed on open access platforms and provide significant insight into linear and nonlinear associations between diagnostic biomarkers. Age, p53, and ATRX status have significant information for the diagnosis of IDH-mutant tumors. The predictive models may facilitate the reduction of false-positive 1p/19q codeletion by fluorescence in situ hybridization (FISH) testing. Conclusions We posit that this approach provides an improvement on the cIMPACT-NOW workflow recommendations for IDH-mutant tumors and a framework for future resource and testing allocation.
Integrated genomic characterization of IDH1-mutant glioma malignant progression
(NATURE PUBLISHING GROUP, 2016-01-01) Bai, Hanwen; Harmanci, Akdes Serin; Erson-Omay, E. Zeynep; Li, Jie; Coskun, Sueleyman; Simon, Matthias; Krischek, Boris; Ozduman, Koray; Omay, S. Buelent; Sorensen, Eric A.; Turcan, Sevin; Bakirciglu, Mehmet; Carrion-Grant, Geneive; Murray, Phillip B.; Clark, Victoria E.; Ercan-Sencicek, A. Gulhan; Knight, James; Sencar, Leman; Altinok, Selin; Kaulen, Leon D.; Guelez, Burcu; Timmer, Marco; Schramm, Johannes; Mishra-Gorur, Ketu; Henegariu, Octavian; Moliterno, Jennifer; Louvi, Angeliki; Chan, Timothy A.; Tannheimer, Stacey L.; Pamir, M. Necmettin; Vortmeyer, Alexander O.; Bilguvar, Kaya; Yasuno, Katsuhito; Guenel, Murat
Gliomas represent approximately 30\% of all central nervous system tumors and 80\% of malignant brain tumors(1). To understand the molecular mechanisms underlying the malignant progression of low-grade gliomas with mutations in IDH1 (encoding isocitrate dehydrogenase 1), we studied paired tumor samples from 41 patients, comparing higher-grade, progressed samples to their lower-grade counterparts. Integrated genomic analyses, including whole-exome sequencing and copy number, gene expression and DNA methylation profiling, demonstrated nonlinear clonal expansion of the original tumors and identified oncogenic pathways driving progression. These include activation of the MYC and RTK-RAS-PI3K pathways and upregulation of the FOXM1- and E2F2-mediated cell cycle transitions, as well as epigenetic silencing of developmental transcription factor genes bound by Polycomb repressive complex 2 in human embryonic stem cells. Our results not only provide mechanistic insight into the genetic and epigenetic mechanisms driving glioma progression but also identify inhibition of the bromodomain and extraterminal (BET) family as a potential therapeutic approach.
Longitudinal analysis of treatment-induced genomic alterations in gliomas
(BIOMED CENTRAL LTD, 2017-01-01) Erson-Omay, E. Zeynep; Henegariu, Octavian; Omay, S. Bulent; Harmanci, Akdes Serin; Youngblood, Mark W.; Mishra-Gorur, Ketu; Li, Jie; Ozduman, Koray; Carrion-Grant, Geneive; Clark, Victoria E.; Caglar, Caner; Bakircioglu, Mehmet; Pamir, M. Necmettin; Tabar, Viviane; Vortmeyer, Alexander O.; Bilguvar, Kaya; Yasuno, Katsuhito; DeAngelis, Lisa M.; Baehring, Joachim M.; Moliterno, Jennifer; Gunel, Murat
Background: Glioblastoma multiforme (GBM) constitutes nearly half of all malignant brain tumors and has a median survival of 15 months. The standard treatment for these lesions includes maximal resection, radiotherapy, and chemotherapy
MEOX2 homeobox gene promotes growth of malignant gliomas
(OXFORD UNIV PRESS INC, 2022-01-01) Schoenrock, Anna; Heinzelmann, Elisa; Steffl, Bianca; Demirdizen, Engin; Narayanan, Ashwin; Krunic, Damir; Baehr, Marion; Park, Jong-Whi; Schmidt, Claudia; Oezduman, Koray; Pamir, M. Necmettin; Wick, Wolfgang; Bestvater, Felix; Weichenhan, Dieter; Plass, Christoph; Taranda, Julian; Mall, Moritz; Turcan, Sevin
Background Glioblastoma (GBM) is an aggressive tumor that frequently exhibits gain of chromosome 7, loss of chromosome 10, and aberrantly activated receptor tyrosine kinase signaling pathways. Previously, we identified Mesenchyme Homeobox 2 (MEOX2), a gene located on chromosome 7, as an upregulated transcription factor in GBM. Overexpressed transcription factors can be involved in driving GBM. Here, we aimed to address the role of MEOX2 in GBM. Methods Patient-derived GBM tumorspheres were used to constitutively knockdown or overexpress MEOX2 and subjected to in vitro assays including western blot to assess ERK phosphorylation. Cerebral organoid models were used to investigate the role of MEOX2 in growth initiation. Intracranial mouse implantation models were used to assess the tumorigenic potential of MEOX2. RNA-sequencing, ACT-seq, and CUT\&Tag were used to identify MEOX2 target genes. Results MEOX2 enhanced ERK signaling through a feed-forward mechanism. We identified Ser(155) as a putative ERK-dependent phosphorylation site upstream of the homeobox-domain of MEOX2. S155A substitution had a major effect on MEOX2 protein levels and altered its subnuclear localization. MEOX2 overexpression cooperated with p53 and PTEN loss in cerebral organoid models of human malignant gliomas to induce cell proliferation. Using high-throughput genomics, we identified putative transcriptional target genes of MEOX2 in patient-derived GBM tumorsphere models and a fresh frozen GBM tumor. Conclusions We identified MEOX2 as an oncogenic transcription regulator in GBM. MEOX2 increases proliferation in cerebral organoid models of GBM and feeds into ERK signaling that represents a core signaling pathway in GBM.
Mutations and Copy Number Alterations in IDH Wild-Type Glioblastomas Are Shaped by Different Oncogenic Mechanisms
(MDPI, 2020-01-01) Ulgen, Ege; Karacan, Sila; Gerlevik, Umut; Can, Ozge; Bilguvar, Kaya; Oktay, Yavuz; B. Akyerli, Cemaliye; K. Yuksel, Sirin; E. Danyeli, Ayca; Tihan, Tarik; Sezerman, O. Ugur; Yakicier, M. Cengiz; Pamir, M. Necmettin; Ozduman, Koray
Little is known about the mutational processes that shape the genetic landscape of gliomas. Numerous mutational processes leave marks on the genome in the form of mutations, copy number alterations, rearrangements or their combinations. To explore gliomagenesis, we hypothesized that gliomas with different underlying oncogenic mechanisms would have differences in the burden of various forms of these genomic alterations. This was an analysis on adult diffuse gliomas, but IDH-mutant gliomas as well as diffuse midline gliomas H3-K27M were excluded to search for the possible presence of new entities among the very heterogenous group of IDH-WT glioblastomas. The cohort was divided into two molecular subsets: (1) Molecularly-defined GBM (mGBM) as those that carried molecular features of glioblastomas (including TERT promoter mutations, 7/10 pattern, or EGFR-amplification), and (2) those who did not (others). Whole exome sequencing was performed for 37 primary tumors and matched blood samples as well as 8 recurrences. Single nucleotide variations (SNV), short insertion or deletions (indels) and copy number alterations (CNA) were quantified using 5 quantitative metrics (SNV burden, indel burden, copy number alteration frequency-wGII, chromosomal arm event ratio-CAER, copy number amplitude) as well as 4 parameters that explored underlying oncogenic mechanisms (chromothripsis, double minutes, microsatellite instability and mutational signatures). Findings were validated in the TCGA pan-glioma cohort. mGBM and ``Others{''} differed significantly in their SNV (only in the TCGA cohort) and CNA metrics but not indel burden. SNV burden increased with increasing age at diagnosis and at recurrences and was driven by mismatch repair deficiency. On the contrary, indel and CNA metrics remained stable over increasing age at diagnosis and with recurrences. Copy number alteration frequency (wGII) correlated significantly with chromothripsis while CAER and CN amplitude correlated significantly with the presence of double minutes, suggesting separate underlying mechanisms for different forms of CNA.
Non-Syndromics Spinal Schwannomas: A Novel Classification
(FRONTIERS MEDIA SA, 2017-01-01) Sun, Ibrahim; Pamir, M. Necmettin
Schwannomas are the most frequent primary tumors of the spine with an incidence of 0.3-0.5/100,000 person per year. Current treatment for non-syndromic spinal schwannomas is total resection of the tumor with preservation of neurovascular structures. This study aims to report neurologic and radiologic outcome following treatment of non-syndromic spinal schwannomas along with a novel tumor classification used in our clinic. A retrospective case series was carried out with a patient sample of 82 male and female patients with non-syndromic spinal schwannomas. All patient data were retrospectively collected from the hospital records. As a routine procedure, after admittance and primary evaluation, patients' tumors were classified using CT or MRI in accordance with our proposed classification method, which employs a dual designation method with tree groups (A, B, and C) for tumor volume and four types (I, II, III, and IV) for tumor localization. Subsequent resection surgery was followed by neurological assessments and follow up at 45th, 180th, and 360th postoperative day. Along with Karnofsky performance status scale, pain, sensory deficits, and motor weakness were scored to assess neurologic recovery. Our finding indicates that patients with different tumor types significantly differ in their neurological scores and show consistent but differential neurological recovery at early and late time points postsurgery. Complications during and postsurgery were minimal, occurring only in two patients. Our findings further reinforce the established safety of total resection operations and indicate that our proposed classification is a simple, effective tool that has proven helpful in preoperative planning and avoiding unnecessary surgical approaches.
Pterional and Unifrontal Approaches for the Microsurgical Resection of Olfactory Groove Meningiomas: Experience with 61 Consecutive Patients
(TURKISH NEUROSURGICAL SOC, 2017-01-01) Guduk, Mustafa; Yener, Ulas; Sun, Halil Ibrahim; Hacihanefioglu, Mehmet; Ozduman, Koray; Pamir, M. Necmettin
AIM: Olfactory groove meningiomas make up 4 to 13\% of meningiomas. The first line treatment of meningiomas is surgery, but the extent and types of approaches advised for olfactory groove meningiomas are diverse, from aggressive skull base approaches to standard or minimally invasive craniotomies and endoscopic approaches. We retrospectively reviewed our series of olfactory groove meningiomas that were operated microsurgically by standard pterional or unifrontal approaches. MATERIAL and METHODS: Our series of 61 olfactory groove meningioma patients operated through pterional or unifrontal approaches between March 1987 and September 2015 was reviewed and the clinical data, radiological findings, surgical treatment and clinical outcomes of the patients were retrospectively analyzed. RESULTS: Sixty-three craniotomies were performed in total. Pterional and unifrontal approaches were used in 38 (60.3\%) and 25 (39.7\%) surgical procedures, respectively. Overall, gross total tumor resection was achieved in 59 (93.7\%) cases. Complications were seen in 8 cases, and 2 of these patients underwent reoperation. Three of the 4 patients where only subtotal resection could be achieved underwent gamma knife radiosurgery. CONCLUSION: Pterional and unifrontal approaches, which are familiar and standard for neurosurgeons, can accomplish high rates of total resection with acceptable complication and recurrence rates for the treatment of olfactory groove meningiomas.
Sequential filtering for clinically relevant variants as a method for clinical interpretation of whole exome sequencing findings in glioma
(BMC, 2021-01-01) Ulgen, Ege; Can, Ozge; Bilguvar, Kaya; Boylu, Cemaliye Akyerli; Yuksel, Sirin Kilicturgay; Danyeli, Ayca Ersen; Sezerman, O. Ugur; Yakicier, M. Cengiz; Pamir, M. Necmettin; Ozduman, Koray
Background In the clinical setting, workflows for analyzing individual genomics data should be both comprehensive and convenient for clinical interpretation. In an effort for comprehensiveness and practicality, we attempted to create a clinical individual whole exome sequencing (WES) analysis workflow, allowing identification of genomic alterations and presentation of neurooncologically-relevant findings. Methods The analysis workflow detects germline and somatic variants and presents: (1) germline variants, (2) somatic short variants, (3) tumor mutational burden (TMB), (4) microsatellite instability (MSI), (5) somatic copy number alterations (SCNA), (6) SCNA burden, (7) loss of heterozygosity, (8) genes with double-hit, (9) mutational signatures, and (10) pathway enrichment analyses. Using the workflow, 58 WES analyses from matched blood and tumor samples of 52 patients were analyzed: 47 primary and 11 recurrent diffuse gliomas. Results The median mean read depths were 199.88 for tumor and 110.955 for normal samples. For germline variants, a median of 22 (14-33) variants per patient was reported. There was a median of 6 (0-590) reported somatic short variants per tumor. A median of 19 (0-94) broad SCNAs and a median of 6 (0-12) gene-level SCNAs were reported per tumor. The gene with the most frequent somatic short variants was TP53 (41.38\%). The most frequent chromosome-/arm-level SCNA events were chr7 amplification, chr22q loss, and chr10 loss. TMB in primary gliomas were significantly lower than in recurrent tumors (p = 0.002). MSI incidence was low (6.9\%). Conclusions We demonstrate that WES can be practically and efficiently utilized for clinical analysis of individual brain tumors. The results display that NOTATES produces clinically relevant results in a concise but exhaustive manner.
Somatic POLE mutations cause an ultramutated giant cell high-grade glioma subtype with better prognosis
(OXFORD UNIV PRESS INC, 2015-01-01) Erson-Omay, E. Zeynep; Caglayan, Ahmet Okay; Schultz, Nikolaus; Weinhold, Nils; Omay, S. Bulent; Ozduman, Koray; Koksal, Yavuz; Li, Jie; Harmanci, Akdes Serin; Clark, Victoria; Carrion-Grant, Geneive; Baranoski, Jacob; Caglar, Caner; Barak, Tanyeri; Coskun, Suleyman; Baran, Burcin; Kose, Dogan; Sun, Jia; Bakircioglu, Mehmet; Gunel, Jennifer Moliterno; Pamir, M. Necmettin; Mishra-Gorur, Ketu; Bilguvar, Kaya; Yasuno, Katsuhito; Vortmeyer, Alexander; Huttner, Anita J.; Sander, Chris; Gunel, Murat
Background. Malignant high-grade gliomas (HGGs), including the most aggressive form, glioblastoma multiforme, show significant clinical and genomic heterogeneity. Despite recent advances, the overall survival of HGGs and their response to treatment remain poor. In order to gain further insight into disease pathophysiology by correlating genomic landscape with clinical behavior, thereby identifying distinct HGG molecular subgroups associated with improved prognosis, we performed a comprehensive genomic analysis. Methods. We analyzed and compared 720 exome-sequenced gliomas (136 from Yale, 584 from The Cancer Genome Atlas) based on their genomic, histological, and clinical features. Results. We identified a subgroup of HGGs (6 total, 4 adults and 2 children) that harbored a statistically significantly increased number of somatic mutations (mean = 9257.3 vs 76.2, P = .002). All of these ``ultramutated{''} tumors harbored somatic mutations in the exonuclease domain of the polymerase epsilon gene (POLE), displaying a distinctive genetic profile, characterized by genomic stability and increased C-to-A transversions. Histologically, they all harbored multinucleated giant or bizarre cells, some with predominant infiltrating immune cells. One adult and both pediatric patients carried homozygous germline mutations in the mutS homolog 6 (MSH6) gene. In adults, POLE mutations were observed in patients younger than 40 years and were associated with a longer progression-free survival. Conclusions. We identified a genomically, histologically, and clinically distinct subgroup of HGGs that harbored somatic POLE mutations and carried an improved prognosis. Identification of distinctive molecular and pathological HGG phenotypes has implications not only for improved classification but also for potential targeted treatments.
Spinal Cavernomas: Outcome of Surgically Treated 10 Patients
(FRONTIERS MEDIA SA, 2017-01-01) Sun, Ibrahim; Pamir, M. Necmettin
Aim: We report the preoperative and postoperative findings and also neurological follow-up results from 10 spinal cavernoma patients treated in our clinic. Several representative cases are presented in terms of clinical features, imaging results, and surgical outcomes. Material and methods: The data were retrospectively collected from patients' files in the hospital records and sorted with regards to clinical presentation, radiologic features, and operative findings. Patients received spinal MRI scans for the diagnosis of spinal cavernomas (SC) and postsurgical evaluation. Clinical presentation was evaluated via Ogilvy classification and symptoms were checked preoperatively and postoperatively at third month and first year using McCormick scale. Primary treatment was microsurgical operation aiming a gross total lesion resection. Results: 10 spinal cavernoma patients between the ages 30 and 63 were treated. Six (60\%) of the patients were diagnosed with cervical and four (40\%) others were diagnosed with thoracic SC. Among the patient group, mean preoperative Ogilvy classification score was 2.3 +/- 0.7.8 and McCormick score was 1.9 +/- 0.7. There was no residual mass or relapse after surgery. One patient developed surgery related left hemiparesis, which was normalized at 1 year follow-up. Conclusion: Patients must be diagnosed with MRI since it is nowadays a gold standard. Preoperative and postoperative scores are important in evaluating the patients' condition and improvement. The results from our patient series also reinforce the notion that immediate surgery should be the preferred treatment method for cavernomas. Intraoperative neurophysiologic monitarization should assist the surgery in order to prevent complications. In conclusion, microsurgery is a gold standard method that we recommend for cases of cavernomas, which will not recur if gross total resection is achieved.
The Carotid Endarterectomy Cadaveric Investigation for Cranial Nerve Injuries: Anatomical Study
(MDPI, 2021-01-01) Cevik, Orhun Mete; Usseli, Murat Imre; Babur, Mert; Unal, Cansu; Eksi, Murat Sakir; Guduk, Mustafa; Ovalioglu, Talat Cem; Aksoy, Mehmet Emin; Pamir, M. Necmettin; Bozkurt, Baran
Cerebral stroke continues to be one of the leading causes of mortality and long-term morbidity