bluuebunny/crossref_metadata_2025_split huggingface dataset:
P04.10 CDKN2A mutational status is associated with venous thromboembolism in patients with glioblastoma
Authors: Kapteijn M Y , Kaptein F H J , Stals M A M , van Duinen S G , Taphoorn M J B , Dirven L , Koekoek J A F , Klok F A , Versteeg H H , Buijs J T 
Published: September 2021

Abstract

BACKGROUND
Patients with glioblastoma have a high risk of developing venous thromboembolism (VTE). However, the underlying genetic risk factors remain largely unknown. Therefore, the aim of our study was to discover whether genetic aberrations in glioblastoma associate with VTE.

MATERIAL AND METHODS
In this retrospective cohort study, all patients diagnosed with glioblastoma between February 2017 and August 2020 in two hospitals (Leiden University Medical Center and Haaglanden Medical Center) were included (n=341). Targeted DNA next-generation sequencing (NGS) had been performed of all glioblastomas for diagnostic purposes and included tumor mutational status of the genes ATRX, BRAF, CIC, FUBP1, H3F3A, IDH1, IDH2, PIK3CA, PTEN and TP53 and amplification/gain or deletion of BRAF, CDKN2A, EGFR, NOTCH1 and PTEN. Through extensive chart review, we collected data on VTE events (deep vein thrombosis and/or pulmonary embolism) three months before until two years after glioblastoma diagnosis, which were adjudicated by an independent investigator. Patients with cerebral vein thrombosis (n=3) and low quality NGS data (n=1; minimum reads/samples: &lt;1.5M and/or minimum depth: &lt;100 reads) were excluded. Cox regression analysis and competing risk analysis (CICR) were performed to compare patients that developed VTE with patients that did not.

RESULTS
Of the 337 patients, 215 had died, 26 were diagnosed with VTE and 37 were lost to follow-up. CDKN2A deletion was found to associate most significantly with VTE (HR: 2.65, 95%CI: 1.18–5.94, p=0.018). Competing risk analysis confirmed this finding, demonstrating a 12-month adjusted cumulative incidence of 12.7% (95%CI: 7.5–19.3) compared to 5.2% (95%CI: 2.5–9.2) in patients with CDKN2A wild-type (p=0.013). No significant association was found between any of the investigated genes, including CDKN2A deletion, and death.

CONCLUSION
This study demonstrates that CDKN2A deletion is associated with VTE in glioblastoma patients. Therefore, CDKN2A mutational status may be a promising predictor to identify patients with glioblastoma at high risk of VTE, who may benefit from thromboprophylaxis.
P07.03 Fluorescence navigation in glioma surgery using 5 ALA and chlorin E6
Authors: Rynda A , Olyushin V , Rostovtsev D 
Published: September 2021

Abstract

BACKGROUND
Metabolic navigation in the surgery of malignant gliomas is the most effective way to distinguish the border of the tumor during surgery and achieve a more radical resection, and as a result, to increase the recurrence interval and increase the life expectancy.

MATERIAL AND METHODS
A comparative analysis of fluorescent navigation was carried out in 50 patients (group 2) with glioma of a high degree of anaplasia, who were treated at the Department of Neurooncology of the A.L. prof. A.L. Polenov. In 25 patients (group 1), chlorin E6 1 mg / kg intravenously was used as a fluorescence inducer, the other 25 patients (group 2) received 5 ALA 20 mg / kg orally. Each group included 10 patients with Grade III anaplasia and 15 patients with Grade IV anaplasia. Both groups were statistically representative (p&gt; 0.05).

RESULTS
For surgery of grade III glioma, the sensitivity of the method was 83.3% (chlorin E6), 82.9% (5ALA); specificity 66.7% (chlorin E6), 65.4% (5ALA). For grade IV glioma surgery, the sensitivity of the method is 87.5% (chlorin E6), 87.7% (5ALA); specificity - 85.7% (chlorin E6), 85.3% (5ALA).

CONCLUSION
Statistical analysis showed comparable high efficacy of the drugs in the surgery of malignant gliomas. The sensitivity and specificity of the method for fluorescent preparations of chlorin E6 and 5 ALA showed no statistically significant difference in the achievement of the result (p&gt; 0.05)
P10.02 Combined methods of a micropump system and a chronic cranial window allows tumor observation with multi photon laser scanning microscopy under continuous treatment
Authors: Weil S , Jung E , Domínguez Azorín D , Higgins J , Reckless J , Ramsden N , Keller P , Grainger D , Wick W , Winkler F 
Published: September 2021

Abstract

BACKGROUND
Glioblastomas are notoriously therapy resistant tumors. As opposed to other tumor entities, no major advances in therapeutic success have been made in the past decades. This has been calling for a deeper biological understanding of the tumor, its growth and resistance patterns. We have been using a xenograft glioma model, where human glioblastoma cells are implanted under chronic cranial windows and studied longitudinally over many weeks and months using multi photon laser scanning microscopy (MPLSM). To test the effect of (new) drugs, a stable and direct delivery system avoiding the blood-brain-barrier has come into our interest.

MATERIAL AND METHODS
We implanted cranial windows and fluorescently labeled human glioblastoma stem-like cells into NMRI nude mice to follow up on the tumor development in our MPLSM model. After tumor establishment, an Alzet® micropump was implanted to directly deliver agents via a catheter system continuously over 28 days directly under the cranial window onto the brain surface. Using the MPLSM technique, the continuous delivery and infusion of drugs onto the brain and into the tumor was measured over many weeks in detail using MPLSM.

RESULTS
The establishment of the combined methods allowed reliable concurrent drug delivery over 28 days bypassing the blood-brain-barrier. Individual regions and tumor cells could be measured and followed up before, and after the beginning of the treatment, as well as after the end of the pump activity. Fluorescently labelled drugs were detectable in the MPLSM and its distribution into the brain parenchyma could be quantified. After the end of the micropump activity, further MPLSM measurements offer the possibility to observe long term effects of the applied drug on the tumor.

CONCLUSION
The combination of tumor observation in the MPSLM and concurrent continuous drug delivery is a feasible and reliable method for the investigation of (novel) anti-tumor agents, especially drugs that are not blood-brain-barrier penetrant. Morphological or even functional changes of individual tumor cells can be measured under and after treatment. These techniques can be used to test new drugs targeting the tumor, its tumor microtubes and tumor cells networks, and measure the effects longitudinally.
P12.03 A Delphi survey to inform core ‘red flag’ symptoms for an electronic patient reported outcome system in glioblastoma follow up
Authors: Luis A , Boele F , Booth T 
Published: September 2021

Abstract

BACKGROUND
Glioblastoma is a common and aggressive primary malignant brain tumour in adults associated with a poor prognosis and considerable symptom burden. Clinical review and serial neuroimaging remain the primary monitoring tools to assess for disease status. However, the evidence base for the existing surveillance imaging schedule is yet to be established. New models of follow up care are needed to demonstrate better patient outcomes in this patient cohort. There are indications that patient-reported outcome measures (PROMs) can contribute to improved survival and maintaining an optimal quality of life in other oncology populations.

MATERIALS AND METHODS
There are no standardised PROMs for the priority symptoms in glioblastoma patients, which can be used for evaluation in clinical care as a surrogate marker for disease progression. A broad set of symptoms were therefore initially identified in a targeted literature search and were further refined via Delphi methodology, with the aim to obtain consensus amongst a small expert panel involved in the care of glioblastoma patients. A three round Delphi email survey was conducted. Consensus was defined as 70% agreement.

RESULTS
Symptom and function constructs were assessed for relevance, relationship to disease and treatment, sensitivity to change, psychometric properties and patient acceptability. Consensus was reached on the red flag symptoms and symptom clusters to monitor, as well as the minimum severity thresholds needed to trigger an alert on an electronic symptom reporting system, which has been developed to allow patient self-reporting of symptoms during treatment.

CONCLUSION
The red flag symptoms to monitor, along with the symptom severity thresholds, informed an app-based symptom reporting system, which is currently being piloted in a feasibility study exploring triggered imaging using ePROMs. This has the potential to inform future clinical practice through development of patient reported biomarkers.
P13.03 Sex-specific influence of androgen receptor gene expression on survival of glioblastoma patients
Authors: Łysiak M , Trybuła M , Malmström A , Mudaisi M , Bratthäll C , Strandeus M , Milos P , Hallbeck M , Söderkvist P 
Published: September 2021

Abstract

BACKGROUND
The mRNA and protein expression of androgen receptor (AR) are upregulated in glioblastoma (GBM) and studies show that use of AR antagonists leads to apoptosis of GBM cells in vitro and reduction of tumor volume in a mouse model. With increased prevalence of GBM among males, the role and genetic alterations of AR are worth investigating, especially taking into account the location of AR on chromosome X and possible sex differences associated with it.

MATERIAL AND METHODS
Copy number (CN) and mRNA expression of AR were tested with droplet digital PCR in 106 fresh frozen GBM samples (34 females and 72 males) collected at Linköping University Hospital. This cohort was also subjected to AR promoter methylation analysis, where 17 CpG sites were the target of pyrosequencing. Methylation levels were then correlated with mRNA gene expression, independently for each sex, using Pearson correlation coefficient. Gene expression of AR was also analyzed in The Cancer Genome Atlas cohort of primary IDH wild type GBM (135 females and 219 males) and association of AR expression and overall survival (OS) was tested with Kaplan-Meier log rank analysis after dichotomization by maximally selected rank statistics.

RESULTS
DNA amplifications, as well as deletions of the AR were detected, with a higher frequency of alterations found in females (26.4% vs. 8.3%). AR gene expression correlated with methylation levels of two CpG sites in females (chrX:67543271, chrX:67543762) and three different CpG sites in males (chrX:67543889, chrX:67543895, chrX:67543899). There was no difference in the AR expression between males and females in neither of the cohorts, but significantly higher AR expression was found in the classical subtype of GBM in TCGA. Survival analysis of the TCGA cohort revealed the opposite effect of AR expression on OS of males and females, with high AR expression correlating with shorter OS in females (13.6 vs.15.7 months, p=0.035) and longer OS in males (16.6 vs. 12.2 months, p=0.04). Additional gene set enrichment analysis of these samples showed that high AR expression was strongly correlated with DNA repair but only in the male group.

CONCLUSION
Our results show that high AR mRNA expression in GBM exhibits different effects on patients’ survival depending on their sex, despite common occurrence of high AR expression and CN changes in males and females. The reasons for potential protective influence of AR in males remain unclear and require further investigations.
P13.14 Inhibition of extracellular carbonic anhydrases reduces glioblastoma cell invasion
Authors: Proescholdt M , Qiu Z , Falter J , Schmidt N 
Published: September 2021

Abstract

BACKGROUND
Malignant gliomas metabolize glucose preferably by glycolysis which is in accordance with the Warburg effect. This induces a high demand of glucose combined with a significant lactic acid load. The hypoxia-inducible carbonic anhydrase (CA) IX has been shown to moderate the extrusion of hydrogen ions into the extracellular space. Since the acidification of the extracellular environment contributes to host tissue invasion due to activation of proteolytic enzymes, we hypothesized that CA IX plays an important role in malignant glioma Recently, specific small molecule inhibitors of this enzyme have been developed and may provide an innovative strategy for anti - invasive treatment.

MATERIAL AND METHODS
Two established and 4 primary GBM cell lines (2 with mesenchymal and 2 with proneural transcriptional profile) were exposed to the CAIX inhibitor U104 under normoxic and hypoxic conditions. Cell toxicity was measured by ATP and crystal violet assay. For invasion assessment, a matrigel invasion chamber system with 8 µm pore size polycarbonate filter was used. CAIX expression was analyzed by quantitative RTPCR and Western Blot.

RESULTS
Hypoxia significantly induced CAIX expression in all cell lines. Invasiveness increased significantly under hypoxic conditions in the mesenchymal cells (p &lt; 0.01). Regardless of oxygenation status, the mesenchymal group displayed significantly higher invasiveness compared to the proneural group (p = 0.006). Looking at all cell lines, invasion is significantly inhibited by U104, both under normoxic and hypoxic conditions (p &lt; 0.01). However, while the mesenchymal group showed the highest susceptibility to CAIX inhibition followed by the proneurally differentiated group, the established cell lines were entirely refractory to CAIX inhibition.

CONCLUSION
Our data demonstrate that CAIX inhibition can effectively inhibit invasion in malignant glioma cells independent from oxygenation status, however the effects are significantly influenced by cell type specific biological features.
P13.16 Metastatic potential of systemic glioblastoma stem cell lines in vivo
Authors: Schwab S G , Sarnow K , Thorsen F A , Hossain J A , Goldbrunner R , Miletic H , Bjerkvig R 
Published: September 2021

Abstract

BACKGROUND
Despite aggressive tumor behavior, extracranial metastases rarely develop in glioblastoma (GBM) patients. Two potential explanations have been suggested: 1) The blood-brain-barrier functions as a physical barrier that prevents the dissemination of GBM cells out of the central nervous system (CNS) or 2) that extracranial metastasis do occur, but the patients die before extracranial metastases manifest themselves. The first theory has been questioned based on the fact that circulating tumor cells (CTC) were found in blood samples of GBM patients without systemic metastases. To date it has not been proven if CTCs are able to reenter the brain and to what extent they are able to form systemic extracranial metastatic lesions. Therefore, the current study aimed at analyzing the dissemination patterns and the underlying mechanisms associated with the ability of GBM CTCs to form extracranial metastases.

MATERIAL AND METHODS
Five highly characterized human GBM stem cell (GSC) lines (P3, BG5, BG7, GG6, GG16), displaying GBM CNV patterns, were intracranially implanted in a first cohort, then transduced with a lentiviral Firefly Luciferase-eGFP vector and injected into the left cardiac ventricle of NOD/SCID mice in a second cohort. Mice were observed closely and tumor burden was assessed using in vivo as well as ex vivo bioluminescence imaging, MRI and PET. Mice were euthanized when the objective endpoint criteria (tumor burden) was met, then organs were harvested and fixed for further analysis.

RESULTS
First, a detailed characterization of the GSC line invasion patterns were assessed when grown as orthotopic xenografts in vivo dividing them into three categories: 1) Highly invasive without apparent angiogenesis (BG5) 2) Invasive with perivascular infiltration and angiogenesis (P3, BG7 and GG16) and 3) Angiogenic and highly circumscribed (GG6). Following intracardial injection, (7 out of 8) P3 animals developed extracranial and intracranial tumors with a distinctive pattern. Brain, adrenal gland, ovary and liver were amongst the organs most susceptible for tumor growth in the P3 group. For the BG5 and BG7 cell lines, no metastases were observed whereas only 1 animal out of 10 developed metastases in both groups GG16 and GG6.

CONCLUSION
Only one out of 5 GSC lines exhibited a strong metastatic potential when injected into the left cardiac ventricle. Compared to other tumors which exhibit a strong metastatic potential from the circulation, GSC lines do only to a very limited extent show this potential reflecting observations made in the clinic.
P14.14 Adjuvant treatment versus initial observation in newly diagnosed WHO grade II and grade III oligodendroglioma: real-life data from two academic, tertiary care centers in Austria
Authors: Mair M J , Leibetseder A , Wöhrer A , Widhalm G , Dieckmann K , Aichholzer M , Weis S , von Oertzen T , Pichler J , Preusser M , Berghoff A S 
Published: September 2021

Abstract

BACKGROUND
Oligodendrogliomas are rare, slow-growing brain tumors with a survival prognosis of &gt;10 years. Although adjuvant radio-chemotherapy has been shown to prolong survival, aggressive treatment comes at the cost of increased toxicity. Systematic data on the optimal timing of adjuvant treatment in oligodendroglioma are lacking.

MATERIAL AND METHODS
Patients treated for a newly diagnosed IDH-mutated, 1p/19q-codeleted oligodendroglioma (WHO grades II/III) in 2000 - 2018 at the Medical University of Vienna or the Kepler University Hospital Linz (Austria) were included in this retrospective study. Adjuvant treatment was defined as radiotherapy (RT), chemotherapy (CHT) or radio-chemotherapy (R-CHT) within 6 months after resection in the absence of progression. “Wait and see” was defined as regular follow up with magnetic resonance imaging and treatment at progression.

RESULTS
185 patients were identified, comprising 123/185 (66.5%) WHO grade II and 62/185 (33.5%) WHO grade III oligodendrogliomas. Median age at diagnosis was 42 years (range: 20–82). Gross total resection (GTR) could be achieved in 77/178 (42.3%) evaluable patients. Adjuvant treatment was applied in 63/185 (38.2%) patients, of whom 43/63 (68.3%) underwent R-CHT, 9/63 (14.3%) CHT only and 11/63 (17.5%) RT only. 43/52 (82.7%) received temozolomide-based treatment, 1/52 (1.9%) procarbazine, lomustine and vincristine (PCV), 1/52 dacarbazine/fotemustine and in 7/52 (13.5%) patients, no data on used regimens was available. Adjuvant treatment was more frequently applied in WHO grade 3 tumors (p&lt;0.001), while there was no association of adjuvant treatment with extent of resection (p=0.24). Patients after GTR who underwent adjuvant therapy presented with longer progression-free survival (PFS) compared to patients initially managed with observation (median: 150 months, 95%CI: 100 - not reached (n.r.) vs. median: 101 months, 95%CI: 73.2–115; p=0.053). In non-GTR tumors, patients with adjuvant therapy presented with a significantly longer median PFS of 107.5 months (95%CI: 62.8-n.r.) as compared to patients initially managed with observation (45.3 months, 95%CI: 41.2–78.8; p=0.025).

CONCLUSION
The application of adjuvant therapy was associated with favorable PFS in patients who underwent resection of newly diagnosed oligodendroglioma in this retrospective study. Prospective clinical trials should investigate the risks and benefits of adjuvant treatment versus initial observation in patients with oligodendroglioma.
P14.17 Conventional MRI criteria differentiate true tumour progression from treatment-induced effects in irradiated WHO grade 3 and 4 gliomas
Authors: Flies C M , van Leuken K H , Verhoeff J J C , de Vos F Y F , Seute T , Robe P A , Hendrikse J , Witkamp T D , Dankbaar J W , Snijders T J 
Published: September 2021

Abstract

BACKGROUND
Post-treatment radiological deterioration of patients with an irradiated high-grade (WHO grade 3 and 4) glioma (HGG) may be the result of true progressive disease (PD) or treatment-induced effects (TIE). Differentiation between these two entities is of great importance, but remains a diagnostic challenge. This study assesses the diagnostic value of conventional MRI characteristics to differentiate PD from TIE in treated HGGs.

MATERIAL AND METHODS
In this single-centre, retrospective cohort study, we included adult patients with a HGG, who were treated with radiotherapy and subsequently developed a new or increasing contrast-enhancing lesion on conventional follow-up MRI. TIE and PD were defined radiologically as stable/decreased for a minimum of six weeks or progressive according to the RANO criteria, and histologically as predominantly TIE without viable tumour or PD. Demographic and clinical data were retrieved. Twenty-one preselected MRI characteristics of the progressive lesions were assessed by two neuroradiologists. The statistical analysis included logistic regression to develop a) a full multivariable model b) a diagnostic model with model reduction, and a Cohen’s Kappa interrater reliability coefficient.

RESULTS
210 patients (median age 61, IQR=54–68, 189 males) with 284 lesions were included, of which 141 (50%) had PD. Median time to PD was 2 (0.7–6.1) and to TIE 0.9 (0.7–3.5) months after RT. In multivariable modelling and after model reduction, the following determinants were significant diagnostic factors: Radiation dose (Odds ratio (OR)=0.68, p=0.017), longer time since radiotherapy (OR=3.56, p&lt;0.0005), certain enhancement patterns (soap bubble enhancement: OR=2.63, p=0.003), isointense apparent diffusion coefficient-signal (OR=2.11, p=0.036), development of multiple new lesions (OR=1.68, p=0.088) and increased marginal enhancement (OR=2.04, p=0.027). ORs of &gt;1 indicate higher odds of PD. The Hosmer & Lemeshow test showed a good calibration (p=0.947) and the area under the ROC-curve was 0.722 (95%-CI=0.66–0.78). Interrater reliability analysis between neuroradiologists revealed moderate to near-perfect agreement for the significantly predictive items, but poor agreement for others.

CONCLUSION
In patients with irradiated high-grade gliomas, several characteristics from conventional MRI are significant predictors for the discrimination between true progression and treatment-induced effects. Interrater reliability for these characteristics was variable. Conventional MRI characteristics from this study should be incorporated into a multimodal diagnostic model that includes advanced imaging techniques.

FUNDING INFORMATION
Foundation Vrienden UMC Utrecht and The StophersenkankerNU Foundation.