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Author: search.filters.author.Ozduman, Koray

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    Oligosarcomas, IDH-mutant are distinct and aggressive
    (SPRINGER, 2022-01-01) Suwala, Abigail K.; Felix, Marius; Friedel, Dennis; Stichel, Damian; Schrimpf, Daniel; Hinz, Felix; Hewer, Ekkehard; Schweizer, Leonille; Dohmen, Hildegard; Pohl, Ute; Staszewski, Ori; Korshunov, Andrey; Stein, Marco; Wongsurawat, Thidathip; Cheunsuacchon, Pornsuk; Sathornsumetee, Sith; Koelsche, Christian; Turner, Clinton; Le Rhun, Emilie; Muhlebner, Angelika; Schucht, Philippe; Ozduman, Koray; Ono, Takahiro; Shimizu, Hiroaki; Prinz, Marco; Acker, Till; Herold-Mende, Christel; Kessler, Tobias; Wick, Wolfgang; Capper, David; Wesseling, Pieter; Sahm, Felix; von Deimling, Andreas; Hartmann, Christian; Reuss, David E.
    Oligodendrogliomas are defined at the molecular level by the presence of an IDH mutation and codeletion of chromosomal arms 1p and 19q. In the past, case reports and small studies described gliomas with sarcomatous features arising from oligodendrogliomas, so called oligosarcomas. Here, we report a series of 24 IDH-mutant oligosarcomas from 23 patients forming a distinct methylation class. The tumors were recurrences from prior oligodendrogliomas or developed de novo. Precursor tumors of 12 oligosarcomas were histologically and molecularly indistinguishable from conventional oligodendrogliomas. Oligosarcoma tumor cells were embedded in a dense network of reticulin fibers, frequently showing p53 accumulation, positivity for SMA and CALD1, loss of OLIG2 and gain of H3K27 trimethylation (H3K27me3) as compared to primary lesions. In 5 oligosarcomas no 1p/19q codeletion was detectable, although it was present in the primary lesions. Copy number neutral LOH was determined as underlying mechanism. Oligosarcomas harbored an increased chromosomal copy number variation load with frequent CDKN2A/B deletions. Proteomic profiling demonstrated oligosarcomas to be highly distinct from conventional CNS WHO grade 3 oligodendrogliomas with consistent evidence for a smooth muscle differentiation. Expression of several tumor suppressors was reduced with NF1 being lost frequently. In contrast, oncogenic YAP1 was aberrantly overexpressed in oligosarcomas. Panel sequencing revealed mutations in NF1 and TP53 along with IDH1/2 and TERT promoter mutations. Survival of patients was significantly poorer for oligosarcomas as first recurrence than for grade 3 oligodendrogliomas as first recurrence. These results establish oligosarcomas as a distinct group of IDH-mutant gliomas differing from conventional oligodendrogliomas on the histologic, epigenetic, proteomic, molecular and clinical level. The diagnosis can be based on the combined presence of (a) sarcomatous histology, (b) IDH-mutation and (c) TERT promoter mutation and/or 1p/19q codeletion, or, in unresolved cases, on its characteristic DNA methylation profile.
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    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
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    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.
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    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
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    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.
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    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.
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    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.
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    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
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    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.
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    Oncolytic Virus Therapy for Glioblastoma Multiforme Concepts and Candidates
    (LIPPINCOTT WILLIAMS \& WILKINS, 2012-01-01) Wollmann, Guido; Ozduman, Koray; van den Pol, Anthony N.
    Twenty years of oncolytic virus development have created a field that is driven by the potential promise of lasting impact on our cancer treatment repertoire. With the field constantly expanding-more than 20 viruses have been recognized as potential oncolytic viruses-new virus candidates continue to emerge even as established viruses reach clinical trials. They all share the defining commonalities of selective replication in tumors, subsequent tumor cell lysis, and dispersion within the tumor. Members from diverse virus classes with distinctly different biologies and host species have been identified. Of these viruses, 15 have been tested on human glioblastoma multiforme. So far, 20 clinical trials have been conducted or initiated using attenuated strains of 7 different oncolytic viruses against glioblastoma multiforme. In this review, we present an overview of viruses that have been developed or considered for glioblastoma multiforme treatment. We outline the principles of tumor targeting and selective viral replication, which include mechanisms of tumor-selective binding, and molecular elements usurping cellular biosynthetic machinery in transformed cells. Results from clinical trials have clearly established the proof of concept and have confirmed the general safety of oncolytic virus application in the brain. The moderate clinical efficacy has not yet matched the promising preclinical lab results