bluuebunny/crossref_metadata_2025_split huggingface dataset:
P02.09.B Valproic acid changes total DNA methylation level and influences temozolomide effect in glioblastoma cell lines
Authors: Barciszewska A , Belter A , Glodowicz P , Naskret-Barciszewska M 
Published: September 2022

Abstract

Background
Valproic acid (VPA) is a first-line antiepileptic drug for glioblastoma (GBM) patients. There is also some evidence it improves the clinical outcome in those patients. However, the exact mechanism of VPA action is vague. Temozolomide (TMZ) is a first-line chemotherapeutic in GBM. Epigenetics offers a connection between genetic and environmental factors that influence the development of the disease. The best-characterized epigenetic mark is 5-methylcytosine (m5C) in DNA. The aim of that project is to show the effects of VPA administration on the total DNA methylation level.

Material and Methods
Using the nucleotide post-labeling method, we analyzed the total amount of m5C in DNA of GBM (T98G, U118, U138), cancer (HeLa) and normal (HaCaT) cell lines treated with VPA, and a combination of VPA and with TMZ.

Results
We adjusted the VPA doses to the ones achieved in the central nervous system during treatment. We observed dose-dependent changes in the total DNA methylation in neoplastic cell lines and the lack of such effect in a normal cell line. VPA alone produced a clear dose-dependent increase in total DNA methylation in GBM cell lines and scarce in the non-neoplastic cell line. In GBM cell lines, TMZ decreased the level of m5C. However, the exposition of GBM cells to the combination of VPA and TMZ caused an adverse synergistic effect resulting in DNA demethylation. The highest loss of m5C was observed at the highest concentration of TMZ (100 μM) and VPA (350 μM), after 3 h of incubation in the T98G cell line.

Conclusion
Total DNA methylation changes in glioma cell lines under VPA treatment suggest the new mechanism of that drug action and promote clinical implications for adjusting VPA and TMZ therapy in GBM patients. Our results show the potential and possible obstacles of the combined therapy of TMZ with VPA. Our experiments show that combined therapy with both drugs leads to total DNA hypomethylation. Therefore the conclusion would be to stop VPA administration during TMZ chemotherapy temporarily.
P03.01.A Late pseudoprogression of vestibular schwannoma after robotic guided stereotactic radiosurgery - Implications for follow-up
Authors: Rueß D , Schütze B , Kocher M , Ruge M 
Published: September 2022

Abstract

Background
Stereotactic radiosurgery (SRS) may cause transient changes of morphology and volume in vestibular schwannomas (VS). This may lead to difficulties in distinguishing treatment-related changes (pseudoprogression) from tumor recurrence (true progression), especially at 12-24 months after treatment. Therefore, we investigated the time course of volume changes of VS after robot-guided SRS.

Material and Methods
We included all patients with unilateral VS who underwent single fraction robotic guided SRS using the Cyberknife® with a minimum follow-up (FU) of 24 months and MR images ≤3 mm slice thickness. Tumor volumes were measured on T1-weighted contrast enhanced images. Volume changes (percentage of tumor volume change compared to baseline) during FU were classified according to RANO criteria (“partial response” (PR) (≥65% decrease), “stable disease” (SD) (&lt;65% decrease; &lt;20% increase), or “progressive disease” (PD) (≥40% increase)). A new status “pseudoprogression” (PP) (&gt;20% transient increase) was defined and divided into early (ePP, occurrence within first &lt;12 months) and late (lPP, &gt;12 months) PP.

Results
Overall 63 patients fulfilled the inclusion criteria. The median age was 56 years (range: 20-82) and the median initial tumor volume was 1.5 cm3 (range: 0.1 - 8.6). All patients received 13 Gy with an isodose level of 80%. The median radiological and clinical FU was 66 months (range: 24-103).
We found PR in 36% (n=23), SD in 35% (n=22) and PP in 29% (n=18). The latter was separated in ePP in 16% (n=10) and lPP in 13% (n=8). The median time to peak in the ePP was six months (range: 4 - 10) and in the lPP 35 months (range: 14 - 61). The median time to return from peak to baseline was seven months in the ePP (range: 5 - 20) and 18 months (range: 6 - 33) in the lPP group. Using these criteria no PD was observed. Additionally, we did not find any significant impact of radiation parameters (coverage, nCi, prescription dose, maximal dose) or patient related parameters (tumor volume, age) on the onset of early and/or late PP.

Conclusion
In our study, we demonstrated that any volume increase assumed to be PD turned out to be ePP or lPP. This might impact the management of VS treated with robotic SRS during FU in favour of further observation.
P03.04.B Garcin syndrome and hippocampal-sparing WBRT: successful resolution of a rare case
Authors: Bonzano E , Russo R , Colombo S , Francia A , Di Liberto R , Filippi A 
Published: September 2022

Abstract

Background
first case of a rare Garcin syndrome resolution in a young metastatic breast cancer(BC) patient treated with a hippocampal-sparing approach.

Material and Methods
we report a case of a 49-year-old caucasian female. The medical record review was relevant for BC diagnoses in 1997, when she was 26yo; complicated by bone and liver metastasis appeared in 2008. In March 2020, she was referred to our department complaining about increasingly worsening left otalgia with initial hearing loss, left facial numbness, and homolateral decreased facial sensitivity, left increased lacrimation, and tingling tongue. Clinical presentation was suggestive for a Guillain-Alajouanine-Garcin Syndrome (Garcin Syndrome), caused by a lytic lesion in the left sphenoid wing. A contrast MRI (02/04/2020) of the brain demonstrated a lytic lesions in the left sphenoid wing, that was noted to infiltrate surrounding bone of the sphenoid sinus wall, including clivus, left pterygoid process and petrous bone; two parietal and occipital bone lesions were identified with a partial leptomeningeal involvement. According to the good PS, she underwent to a hippocampal-sparing WBRT VMAT plus a sequential boost on sphenoid lesion. PTV and OARs were delineated according to a fused planning MRI/CT image. Bilateral hippocampal contours were generated on the set according to RTOG 0933 contouring atlas. After that, a hippocampal avoidance(HA) region was created by expanding the hippocampal contours by 5 mm in all directions according to Brown et al.The PTV-HA was defined as the WB parenchyma, meninges and skull, excluding the HA-region, dose prescription 30Gy/10fx; the PTV-Boost was defined as the sphenoidal metastases, dose prescription of sequential boost was 12Gy/4fx. VMAT was used to deliver the conformal RT plan. Planning priorities that should be followed were:Hippocampus, OpticChiasm, OpticNerve_L or OpticNerve_R, Lens_L or Lens_R.

Results
The neurological symptoms improved after the end of RT with a complete resolution two months later. At the last MRI, a year and a half from the end of RT, there was no evidence of brain lesion, and no neurological symptoms were referred. These are our results of plan sum: for PTV-HA D2%=43.43 Gy, D98%=26.36 Gy, V30=94.96%; for Hippocampus D100%=8.78 Gy, Dmax=17.24 Gy; for Left OpticNerve Dmax=33.51%; for Right OpticNerve Dmax=29.25%; for OpticChiasm Dmax=35.93%.

Conclusion
To our knowledge, this is the first described case using the VMAT technique to spare the hippocampus plus a boost in a rare case of Garcin Syndrome. Prevention of neurocognitive sequelae by hippocampal avoidance has shown promise in several studies as in this case. Sequential boost demonstrated to be feasible and effective.Advanced RT techniques may be used to customize a treatment that allows preserving cognitive impairment achieving good clinical results in the long-term survival of metastatic patients.
P04.04.A A comprehensive genomic study of 390 H3F3A-mutant pediatric-type diffuse high-grade gliomas WHO CNS grade 4
Authors: Willimas E A , Brastianos P K , Wakimoto H , Santagata S , Cahill D P , Juratli T A 
Published: September 2022

Abstract

Background
Histone gene mutant malignant gliomas - H3K27-altered diffuse midline glioma (DMG) and diffuse hemispheric glioma (DHG) H3G34-mutant - occur in all age groups and can have significant variation in clinical outcomes. Here, we report comprehensive genomic profiling from one of the largest collections of H3F3A-mutant gliomas analyzed to date, identifying subsets defined by recurrently co-mutated genes.

Material and Methods
We identified 390 H3F3A-mutant diffuse gliomas WHO grade 4 (201 females and 189 males) that were profiled in the comprehensive genomic profiling program at Foundation Medicine between 2013-2020. Information from pathology reports, histopathology review, and patient clinical data was assessed

Results
Our cohort comprised 304 (77.9%) H3K27M-mutant DMG WHO grade 4 (156 females and 148 males) and 86 H3G34-mutant DHG (45 females and 41 males) with a median age of 20 years (1- 74 years). H3K27M-mutant DMG distributed equally between pediatric and adult patients, with 52% of the patients older than 20 years, 30% older than 30 years, and 18% older than 40 years at the time of first diagnosis. Clonal FGFR1 hotspot mutations were exclusively detected in K27M-mutant DMG (n = 64/304, 21%; p=0.0001), with a significant association with a higher age at first diagnosis (median 32.5 years), and with a wide tumor distribution across the diencephalon. Additional genes which were significantly more frequently altered in K27M-mutant compared to G34-mutant diffuse gliomas included NF1 (31% vs. 8.1%; p=0.0001) and PIK3CA/PIK3R1 (27.9% vs. 15.1%; p=0.016). Conversely, targetable alterations of the cell-cycle pathway (CDK4/6 amplifications and CDKN2A/B deletions) were enriched in H3G34-mutant DHG (26%) compared to H3K27M-mutant DMG (7%). Potentially targetable PDGFR alterations were present in 32.5% of H3G34-mutant DHG and in 18% of H3K27M-mutant DMG.

Conclusion
These data expand our understanding of the tumor-specific molecular features of pediatric-type high-grade gliomas, identifying cohort sub-structure by recurrent co-mutations, which can inform diagnosis and clinical trial design.
P05.05.B A new IDH-wildtype glioma subtype characterized by highly diffuse growth pattern, distinct epigenetic profile and relatively favorable prognosis
Authors: Münch A , Teichmann D , Kuzman P , Spille D , Perez E , May S , Mueller W , Kombos T , Nazari-Dehkordi S , Onken J , Vajkoczy P , Ntoulias G , Paulus W , Heppner F , Koch A , Capper D , Kaul D , Thomas C , Schweizer L 
Published: September 2022

Abstract

Background
DNA methylation profiling has emerges as a powerful approach to CNS tumor classification and the discovery of novel, molecularly distinct entities. With the release of the 12.5 version of the Heidelberg Brain Tumor Classifier, some unclassifiable cases can be assigned to novel methylation classes. We retrospectively reviewed our databases and identified 16 previously unclassifiable cases, all of which belong to the provisional methylation class “adult-type diffuse high-grade glioma, IDH-wildtype, subtype F (HGG_F)”.

Material and Methods
We clinically, radiologically and morphologically characterized 16 HGG_F cases and compared them to 347 glioblastomas. We additionally analyzed copy-number alterations and performed DNA exome sequencing.

Results
Median age at diagnosis of the 12 males and 4 females was 65 years. Upon initial diagnostic workup, specimens were classified as CNS tissue with reactive changes (n=3) or suspicious for the infiltration zone of a diffuse glioma (n = 13). None of the cases demonstrated endothelial proliferation or necrosis and 10/16 tumors had flat copy number profiles. Radiological characteristics were reminiscent of gliomatosis cerebri in eight cases and 9/9 cases had normal FET-PET scans. Whole-exome sequencing revealed genetic alterations frequently found in IDH-wildtype glioblastomas, including TERT promoter mutations in 11/14 (78.6%) and PIK3 mutations (10/14, 71.4%). Outcome was significantly better compared to TCGA IDH-wildtype glioblastomas with a median progression-free survival of 58 months and overall survival of 73 months (both p&lt;0.001).

Conclusion
We provide evidence that TERT promoter mutations in diffusely infiltrating gliomas without further morphological or molecular signs of high-grade glioma should be interpreted in the context of the clinico-radiological presentation as well as epigenetic prolife and may not be suitable as standalone diagnostic marker for glioblastoma, IDH wildtype.
P06.03.A Combination of EGFRvIII CAR T cell therapy and paracrine GAM modulation for the treatment of GBM
Authors: Martins T A , Tatari N , Ritz M , Shekarian T , Schmassmann P , Kaymak D , Hutter G 
Published: September 2022

Abstract

Background
The glioblastoma (GBM) immune microenvironment mainly consists of protumoral glioma-associated microglia and macrophages (GAMs). Previously, we showed that blockade of the don't-eat-me signal CD47, overexpressed by GBM cells, rescued GAMs' phagocytic function in mice. However, CD47 blockade monotherapy has been ineffective in treating human solid tumors to date. Thus, we propose a combinatorial approach of local chimeric antigen receptor (CAR) T cell therapy with paracrine GAM modulation for a synergistic elimination of GBM.

Material and Methods
We lentivirally transduced healthy donor human T cells to generate humanized EGFRvIII-directed CAR T that constitutively secrete a SIRPγ-related protein (SGRP) with high affinity to CD47. Killing assays were performed with endogenous EGFRvIII-expressing BS153 or EGFRvIII-overexpressed U251 GBM cells and assessed by Incucyte time-lapse imaging analysis. CAR T cell activation was confirmed by flow cytometry (FC) and IFNγ was detected from co-culture supernatants or mouse plasma by ELISA. The CAR T cell secretome was analyzed by liquid chromatography-mass spectrometry (LC-MS) to confirm the secretion of SGRP. NSG mice were orthotopically implanted with either EGFRvIII+ BS153 or U251 cells and treated intratumorally with one or two CAR T cell infusions.

Results
EGFRvIII and EGFRvIII-SGRP CAR T proliferated and killed tumor cells in vitro in a dose-dependent manner within 72h with complete cytotoxicity at E:T 1:1 compared to CD19 CAR T. CAR T cells specifically co-expressed CD25 and CD107a and secreted IFNγ in the presence of tumor antigen (24h CD25/CD107a co-expression: EGFRvIII=59.3±3.00%, EGFRvIII-SGRP=52.6±1.42%, CD19=0.1±0.07%; 24h IFNγ secretion: EGFRvIII=173.6±2.50%, EGFRvIII-SGRP=113.8±6.42%, CD19=4.5±1.49%). Differential expression analysis of the CAR T cell secretome identified SGRP in EGFRvIII-SGRP CAR T supernatants (-Log10qValue/Log2fold-change=13.72/6.62). Consistent with studies of systemic EGFRvIII CAR T cell therapy, our data suggest that intratumoral EGFRvIII CAR T were insufficient to eliminate BS153 tumors with endogenous EGFRvIII (Overall survival; EGFRvIII: 20%, CD19: 0%, n=5/group).

Conclusion
Here, we show that EGFRvIII CAR T specifically targeted and killed EGFRvIII+ GBM cells in vitro, but failed to control tumor growth in vivo without GAM modulation. EGFRvIII-SGRP CAR T secretome analysis identified SGRP from the supernatants of unstimulated monocultures. SGRP impaired the binding of SIRPα-Fc to CD47-upregulated GBM cells in vitro, but did not elicit macrophage-mediated phagocytosis of GBM cells in our current in vitro experimental setup. Future work will focus on the functional characterization of SGRP and on further investigating the additive effect of CAR T cell therapy and GAM modulation using translational in vivo and ex vivo models.
P07.09.A Intra operative mapping and monitoring of the cortico-spinal tracts with neurophysiological assessment in intra axial brain tumor resection
Authors: oxman l , emanuel s , zarchi o 
Published: September 2022

Abstract

Background
Preserving motor function is a major challenge in surgery for intra axial brain tumors. In the past two decades, rapid developments in neuroscience, have fueled the growth of intraoperative neurophysiologic monitoring and mapping. Neurophysiological motor mapping allows identification with subsequent preservation of functionally viable nervous tissue. Currently, continuous mapping is typically achieved by electrostimulating via connection to a surgical tool, )e.g., suction(, establishing a stimulation threshold for inducing a motor response, and stopping the resection when reaching motor responses at low electrostimulation levels of 2-10 mA. While most authors report the use of monopolar electrostimulation, which tends toward high sensitivity - low specificity, others report the use of bipolar electrostimulation, which tends toward high specificity - low sensitivity results. Here we report an investigation of the differences between monopolar and bipolar electrostimulation for motor mapping, comparing the sensitivity and specificity of the two methods.

Material and Methods
Gross motor function was evaluated preoperative and 1d postoperative. During the resection, a minimal monopolar electrostimulation threshold was determined, bordering motor tracts. Next, a bipolar probe was used to assess the bipolar electrostimulation threshold at the same location, and a neuro-navigation system was used to mark these locations. The respondent myotomes at each location was documented, as well as the neuromonitoring MEP responses. Postoperatively, the distance between the stimulated marked location, resection borders, and the motor brain structures were assessed. Analysis probed the differences between monopolar and bipolar thresholds in mapping cortical and subcortical motor system and their association with motor neuromonitoring and postoperative motor function.

Results
A prospective intraoperative analysis was conducted on two patients undergoing resection of intra axial tumors at the authors' institution in January 2021. The resection was performed by all clinical standard procedures. Following the resection, additional stimuli were applied by the bipolar probe, to assess the accuracy of the threshold that was needed to evoke a clinical motor response. We found that the bipolar threshold was higher than the conventional threshold used by the monopolar probe in the borders of the resection.

Conclusion
Our findings suggest the bipolar stimuli can give more accuracy in determining the motor function of certain anatomical structures which can lead to better results in the maximal safe resections goal and allow neurosurgeons another intra operative tool to achieve the best outcomes for their patients.
P07.12.B Brain Biopsy with Optical Guidance
Authors: Richter J , Klint E , Wårdell K 
Published: September 2022

Abstract

Background
Accurate stereotactic biopsies of brain tumors are imperative for diagnosis and decisions on therapy. Repetitive needle insertions owing to inconclusive tissue samples enhance increased risks of brain lesioning, hemorrhage and prolonged procedure. Previously we reported on frame-based stereotactic biopsies with a combined 5-ALA fluorescence and laser Doppler flowmetry detection system[1]. The system has now been adapted to frameless navigation with a modified biopsy needle and a new registration system[2].

Material and Methods
Planning was effected with the Medtronic Stealth System. The optical probe was inserted inside the outer cannula of the biopsy needle, which had an opening at the tip, enabling optical measurements ahead of the needle in real-time while manually forwarding it along the trajectory to the target. Fluorescence spectra, microvascular blood flow, and tissue grayness were recorded during insertion. The biopsies were taken where the fluorescence indicated tumor tissue; the optical probe was replaced by the inner cannula. The diagnoses were compared with the fluorescence signals.

Results
In the 9 examined patients the fluorescence measurements and pathological diagnosis of high-grade gliomas or lymphomas matched. Only one needle insertion was necessary. The optical measurements along the trajectory took 5-10 min to the target, the pathological diagnosis was reported after 30-70 min. The probe provided direct feedback of increased blood flow along the trajectory and of malignant tissue in the vicinity of the target.

Conclusion
The optical probe can detect tumor before any tissue is retrieved. If fluorescence is registered, pathological tissue is safely identified. The method can increase the precision and safety of the biopsy and shorten the procedure. The new multimodal probe and the improved registration unit will be tested with other stereotactic and navigation systems and at other neurosurgical centers.
Also, the parallel project on fluorescence guided resection of high-grade gliomas is continued[3].

References
[1] Johan Richter, Neda Haj-Hosseini, Peter Milos, Martin Hallbeck, Karin Wårdell, (2021), Optical Brain Biopsy with a Fluorescence and Vessel Tracing Probe, Operative Neurosurgery, 217-224, 21(4) [2] Elisabeth Klint, Stina Mauritzon, Bengt Ragnemalm, Johan Richter, Karin Wårdell, (2021), FluoRa - a System for Combined Fluorescence and Microcirculation Measurements in Brain Tumor Surgery, Annual International Conference of the IEEE , 1512-1515 [3] Johan Richter, Neda Haj-Hosseini, Martin Hallbeck, Karin Wårdell, (2017), Combination of hand-held probe and microscopy for fluorescence guided surgery in the brain tumor marginal zone, Photodiagnosis and Photodynamic Therapy, 184-192, 18