Araştırma Çıktıları
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Item 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.Item No evidence for a BRD2 promoter hypermethylation inblood leukocytes of Europeans with juvenile myoclonic epilepsy(WILEY, 2019-01-01) Schulz, Herbert; Ruppert, Ann-Kathrin; Zara, Federico; Madia, Francesca; Iacomino, Michele; Vari, Maria S.; Balagura, Ganna; Minetti, Carlo; Striano, Pasquale; Blanche, Amedeo; Marini, Carla; Guerrini, Renzo; Weber, Yvonne G.; Becker, Felicitas; Lerche, Holger; Kapser, Claudia; Schankin, Christoph J.; Kunz, Wolfram S.; Moller, Rikke S.; Oliver, Karen L.; Bellows, Susannah T.; Mullen, Saul A.; Berkovic, Samuel F.; Scheffer, Ingrid E.; Caglayan, Hande; Ozbek, Ugur; Hoffmann, Per; Schramm, Sara; Tsortouktzidis, Despina; Becker, Albert J.; Sander, ThomasJuvenile myoclonic epilepsy (JME) is a common syndrome of genetic generalized epilepsies (GGEs). Linkage and association studies suggest that the gene encoding the bromodomain-containing protein 2 (BRD2) may increase risk of JME. The present methylation and association study followed up a recent report highlighting that the BRD2 promoter CpG island (CpG76) is differentially hypermethylated in lymphoblastoid cells from Caucasian patients with JME compared to patients with other GGE subtypes and unaffected relatives. In contrast, we found a uniform low average percentage of methylation (<4.5\%) for 13 CpG76-CpGs in whole blood cells from 782 unrelated European Caucasians, including 116 JME patients, 196 patients with genetic absence epilepsies, and 470 control subjects. We also failed to confirm an allelic association of the BRD2 promoter single nucleotide polymorphism (SNP) rs3918149 with JME (Armitage trend test, P=0.98), and we did not detect a substantial impact of SNP rs3918149 on CpG76 methylation in either 116 JME patients (methylation quantitative trait loci {[}meQTL], P=0.29) or 470 German control subjects (meQTL, P=0.55). Our results do not support the previous observation that a high DNA methylation level of the BRD2 promoter CpG76 island is a prevalent epigenetic motif associated with JME in Caucasians.Item DNA Methylation of PI3K/AKT Pathway-Related Genes Predicts Outcome in Patients with Pancreatic Cancer: A Comprehensive Bioinformatics-Based Study(MDPI, 2021-01-01) Faleiro, Ines; Roberto, Vania Palma; Demirkol Canli, Secil; Fraunhoffer, Nicolas A.; Iovanna, Juan; Gure, Ali Osmay; Link, Wolfgang; Castelo-Branco, PedroSimple Summary Pancreatic cancer is a highly lethal malignancy. Dysregulation of epigenetic mechanisms leads to abnormal patterns of gene expression contributing to the development and progression of cancer. We explored the ability of DNA methylation of PI3K-related genes to differentiate between malignant and healthy pancreatic tissue using distinct pancreatic cancer cohorts, and found that the methylation levels of the ITGA4, SFN, ITGA2, and PIK3R1 genes are altered in tumour samples since the early stages of malignant transformation and could serve as new diagnostic tools. We also demonstrate that these alterations correlate with overall survival and recurrence-free survival of the patients suggesting that its assessment can serve as independent prognostic indicators of patients' survival with higher sensitivity and specificity than the currently implemented biomarkers. Therefore, the methylation profile of genes involved in this pathway may be an alternative method for predicting cell malignancy and help doctors' decisions on patient care. Pancreatic cancer (PCA) is one of the most lethal malignancies worldwide with a 5-year survival rate of 9\%. Despite the advances in the field, the need for an earlier detection and effective therapies is paramount. PCA high heterogeneity suggests that epigenetic alterations play a key role in tumour development. However, only few epigenetic biomarkers or therapeutic targets have been identified so far. Here we explored the potential of distinct DNA methylation signatures as biomarkers for early detection and prognosis of PCA. PI3K/AKT-related genes differentially expressed in PCA were identified using the Pancreatic Expression Database (n = 153). Methylation data from PCA patients was obtained from The Cancer Genome Atlas (n = 183), crossed with clinical data to evaluate the biomarker potential of the epigenetic signatures identified and validated in independent cohorts. The majority of selected genes presented higher expression and hypomethylation in tumour tissue. The methylation signatures of specific genes in the PI3K/AKT pathway could distinguish normal from malignant tissue at initial disease stages with AUC > 0.8, revealing their potential as PCA diagnostic tools. ITGA4, SFN, ITGA2, and PIK3R1 methylation levels could be independent prognostic indicators of patients' survival. Methylation status of SFN and PIK3R1 were also associated with disease recurrence. Our study reveals that the methylation levels of PIK3/AKT genes involved in PCA could be used to diagnose and predict patients' clinical outcome with high sensitivity and specificity. These results provide new evidence of the potential of epigenetic alterations as biomarkers for disease screening and management and highlight possible therapeutic targets.