Identification of Predictive Response Markers and Novel Treatment Targets for Gliomas

Gliomas are the most frequent primary brain tumors in adults. Despite multimodality treatment strategies, the survival of patients with a diffuse glioma remains poor. There has been an increasing use of molecular markers to assist diagnosis and predict prognosis and response to therapy. Although several prognostic and predictive response markers have been identified, considerable research still needs to be done to improve on these. Therefore, the identification of novel predictive response markers and therapeutic targets are desperately needed for this dismal disease. In this thesis, we describe prognostic and identify novel predictive markers in randomized clinical trials. We determined the gene expression profiles of samples of anaplastic oligodendrogliomas and oligoastrocytomas from the EORTC 26951 study and samples of recurrent glioblastomas of the BELOB study to evaluate the treatment responses within defined intrinsic glioma subtypes (IGSs). IGSs are molecularly similar tumors that have been previously identified by unsupervised gene expression analysis. We found that IGSs can be used to assess the molecular heterogeneity within clinical trials. In addition, we confirmed that IGS subtypes are prognostic for survival and predictive. Tumors assigned to IGS-9 showed benefit from adjuvant PCV chemotherapy. In the BELOB study, we found that tumors assigned to IGS-18 (classical GBMs) showed a trend towards benefit from Beva+CCNU treatment. Expression of FMO4 and OSBPL3 were particularly associated with treatment response. Intrinsic subtypes can therefore be used to assess the molecular heterogeneity within clinical trials and may be used as a prognostic and predictive marker. Another method to profile gliomas is based on DNA methylation. We performed genome-wide methylation profiling on material from EORTC 26951 and assessed CIMP and MGMT-STP27 status. We have shown that survival in patients with CIMP+ or MGMT-STP27 methylated tumors was improved compared to CIMP- and/or MGMT-STP27 unmethylated tumors. Importantly, the MGMT-STP27 status was predictive for response to adjuvant PCV chemotherapy in these tumors. MGMT-STP27 may therefore be used to identify AODs and AOAs with improved prognosis and identify patients that are likely to benefit from adjuvant PCV chemotherapy. We also performed functional analysis on different mutations on the EGFR gene and infrequently mutated genes in oligodendrogliomas. We have shown that different mutations within a single gene (EGFR) can have different molecular consequences and have different binding partners for EGFRvIII, EGFRL858 and EGFRwildtype. As these mutations have different functions, each mutation may need its own unique treatment. Functional analysis on infrequently mutated genes showed that the function of many of ‘low frequency’ genes, differs from its wildtype counterpart. This differential effect suggests that these genes can contribute to the disease and therefore may offer new therapeutic targets for oligodendrogliomas

First experience with cryoballoon ablation for atrial fibrillation in Republic of Moldova

Medpark International Hospital, Cardiology and Interventional Cardiology Department, Nicolae Testemitanu State University of Medicine and Pharmacy of the Republic of Moldova, TOBB University of Economics and Technology Hospital, Cardiology Department, Ankara, Turkey, The 8th International Medical Congress for Students and Young Doctors, September 24-26, 2020Introduction. Pulmonary vein isolation is an established therapy for symptomatic atrial fibrillation (AF). The second generation cryoballoon is effective in achieving pulmonary vein isolation. In 2018 we implemented the cryoballoon ablation (CBA) in Republic of Moldova.Aim of the study. To assess the freedom from AF recurrence after CBA. Materials and methods. A retrospective study was performed in 8 consecutive patients who underwent CBA using Arctic Front Advance cryoballoon (Medtronic) for paroxysmal or persistent AF from June 2018 till December 2019 in Medpark International Hospital. We followed up the patients from June 2018 till March 2020. The information about the clinical symptoms and ECG data during follow-up was collected to identify the presence of recurrence. A recurrence after CBA was considered AF episode that lasted at least 30 seconds. Continuous variables are presented as mean ± SD. Kaplan–Meier analysis was used to determine the probability of freedom from AF during follow-up. Results. A total number of 8 patients with a mean age of 60.13 ± 6.88 years with paroxysmal (n=7; 87.5%) or persistent (n=1; 12.5%) AF were identified. There were 6 males (75%) and 2 females (25%). All patients had a successful pulmonary vein isolation procedure with 100% of veins isolated. No patient had complication during procedure as phrenic nerve palsy, stroke or pericardial effusion. After a 3-month blanking period during a mean follow-up of 337 ± 135 days there were 2 (25%) AF recurrences. One patient developed atrial flutter but not AF in the follow-up period with restoration of sinus rhythm with electrical cardioversion. The average days before recurrence was 120.5 ± 41.72 (150 and 90). Freedom from AF recurrence was 75% at 11,2 months follow-up. Conclusions. The second generation cryoballoon ablation is an effective method of treatment for atrial fibrillation. Our results are compatible with the success rate that is reported by majority of the studies

Treatment for ventricular tachycardia in the absence of structural heart disease

Medpark International Hospital, Cardiology and Interventional Cardiology Department, Nicolae Testemitanu State University of Medicine and Pharmacy of the Republic of Moldova, TOBB University of Economics and Technology Hospital, Cardiology Department, Ankara, TurkeyBackground. According to the recent data in up to 10% of the patients with ventricular tachycardia (VT) there is an absence of structural heart disease. Several types of VT could be present in such patients: right ventricular outflow tract (RVO T) VT, caticholaminergic polymorphic VT, idiopathic left VT, Brugada syndrome, long QT syndrome. According to the VT type the management can be pharmacological therapy, radio-frequency ablation, implantation of cardioverter defibrillator or a combination of them. The decision about the management is based on the type of VT, data obtained from echocardiography, magnetic resonance imaging (MRI) and electrophysiological study (EPS)

Tumor-specific mutations in low-frequency genes affect their functional properties

Causal genetic changes in oligodendrogliomas (OD) with 1p/19q co-deletion include mutations in IDH1, IDH2, CIC, FUBP1, TERT promoter and NOTCH1. However, it is generally assumed that more somatic mutations are required for tumorigenesis. This study aimed to establish whether genes mutated at low frequency can be involved in OD initiation and/or progression. We performed whole-genome sequencing on three anaplastic ODs with 1p/19q co-deletion. To estimate mutation frequency, we performed targeted resequencing on an additional 39 ODs. Whole-genome sequencing identified a total of 55 coding mutations (range 8–32 mutations per tumor), including known abnormalities in IDH1, IDH2, CIC and FUBP1. We also identified mutations in genes, most of which were previously not implicated in ODs. Targeted resequencing on 39 additional ODs confirmed that these genes are mutated at low frequency. Most of the mutations identified were predicted to have a deleterious functional effect. Functional analysis on a subset of these genes (e.g. NTN4 and MAGEH1) showed that the mutation affects the subcellular localization of the protein (n = 2/12). In addition, HOG cells stably expressing mutant GDI1 or XPO7 showed altered cell proliferation compared to those expressing wildtype constructs. Similarly, HOG cells expressing mutant SASH3 or GDI1 showed altered migration. The significantly higher rate of predicted deleterious mutations, the changes in subcellular localization and the effects on proliferation and/or migration indicate that many of these genes functionally may contribute to gliomagenesis and/or progression. These low-frequency genes and their affected pathways may provide new treatment targets for this tumor type

A validated microRNA profile with predictive potential in glioblastoma patients treated with bevacizumab

Purpose: We investigated whether microRNA expression data from glioblastoma could be used to produce a profile that defines a bevacizumab responsive group of patients. Patients and Methods: TCGA microRNA expression data from tumors resected at first diagnosis of glioblastoma in patients treated with bevacizumab at any time during the course of their disease were randomly separated into training (n=50) and test (n=37) groups for model generation. MicroRNA-seq data for 51 patients whose treatment included bevacizumab in the BELOB trial were used as an independent validation cohort. Results: Using penalized regression we identified 8 microRNAs as potential predictors of overall survival in the training set. We dichotomized the response score based on the most prognostic minimum of a density plot of the response scores (log-rank HR=0.16, p=1.2e-5) and validated the profile in the test cohort (one-sided log-rank HR=0.34, p=0.026). Analysis of the profile using all samples in the TCGA glioblastoma dataset, regardless of treatment received, (n=473) showed that the prediction of patient benefit was not significant (HR=0.84, p=0.083) suggesting the profile is specific to bevacizumab. Further independent validation of our microRNA profile in RNA-seq data from patients treated with bevacizumab (alone or in combination with CCNU) at glioblastoma recurrence in the BELOB trial confirmed that our microRNA profile predicted patient benefit from bevacizumab (HR=0.59, p=0.043). Conclusion: We have identified and validated an 8-microRNA profile that predicts overall survival in patients with glioblastoma treated with bevacizumab. This may be useful for identifying patients who are likely to benefit from this agent

Afyonkarahisar İli Dinar İlçesi Patates Ekim Alanlarında Toprakların Verimliliği ve Bitkilerin Beslenme Durumlarının Belirlenmesi

Bu çalışma, Afyonkarahisar ilinin Dinar ilçesinin on köyünde (Tatarlı, Haydarlı, Alpaslan, Okçular, Kadılar, Kınık, Doğanlı, Okçular, Yıprak, Göçerli) patates tarımı yapılan 70 farklı araziden alınan toprakların verimlilik ve bitkilerin beslenme durumunu belirlemek amacıyla yürütülmüştür. Bu amaçla belirlenen arazilerden araziyi temsil edecek şekilde 0-20 cm derinlikten toprak ve bu alanlarda yetiştirilen patates bitkilerinden örnekler alınmıştır. Alınan toprak örneklerinde toplam N, değişebilir K, Ca, Mg ve bitkiye yarayışlı P, Fe, Zn, Mn ve Cu içerikleri belirlenmiştir. Ayrıca toprakların bünyesi ve genel kimyasal özelliklerini ortaya koymak amacıyla pH, EC ve organik madde (OM) içerikleri de belirlenmiştir. Toprak örneklerine ait analiz sonuçları, sınır değerleri ile karşılaştırılarak, örnekleme yapılan toprakların verimlilik durumları ortaya konulmuştur. Bitki örneklerinde ise toplam N, P, K, Mg, Ca, Fe, Zn, Mn ve Cu konsantrasyonları belirlenmiştir. Araştırma sonuçlarına göre, toprakların bünyeleri killi tın yapıdadır. Toprakların pH’ ları hafif alkali reaksiyonlu, ayrıca çoğunlukla hafif tuzludur (% 67). Toprak örneklerinin % 72.9’ u orta ve % 25.7’ si fazla kireçli, organik madde içeriklerinin ise az (% 81) ve orta (% 12.8) düzeyde olduğu belirlenmiştir. Toprak örneklerinin genellikle N, P, K, Ca, Mg, Fe, Mn, Cu içerikleri bakımından yeterli fakat Zn içeriği bakımından yetersiz (% 67.1) olduğu tespit edilmiştir. Bitki örneklerinin N, P, K, Ca, Mg, Mn, Cu içerikleri yeterli bulunurken % 55.7’ sinde Fe, % 41’inde Zn eksikliği belirlenmiştir