bluuebunny/crossref_metadata_2025 huggingface dataset:
OS9.5 Evidence that adult glioblastoma adapts to standard therapy though chromatin remodeling
Authors: Rippaus N , Manning J , Droop A , Al-Jabri M , Care M , Bruns A F , Jenkinson M D , Brodbelt A , Chakrabarty A , Ismail A , Short S , Stead L F
Published: September 2019

BACKGROUND

Glioblastoma (GBM) tumours recur following standard treatment in almost all cases. We use ‘omics technologies to simultaneously profile pairs of primary and matched recurrent GBM to specifically identify and characterise the cells that resisted treatment, with the aim of determining how to more effectively kill them.

MATERIAL AND METHODS

We have analysed high coverage RNAseq data from pairs of GBM tumours: primary de novo tumour and matched local recurrence from patients that underwent standard therapy. Our original cohort constituted 23 pairs and our validation cohort was an additional 22 pairs. We also cultured two plates of spheroids directly from a patient’s GBM, treating one with radiation and temozolomide. We monitored growth and captured and sequenced RNA from single cells at two time-points: one week post-treatment when the deviation between untreated and treated spheroid growth curves was most pronounced; and three weeks post-treatment when the growth rate of treated spheroids had recovered. We investigated differential gene expression between primary and recurrent pairs, and single cells pre- and post-treatment, and performed a bespoke per patient gene set enrichment analysis.

RESULTS

Differential gene expression analysis in 23 tumour pairs indicated a treatment-induced shift in cell states linked to normal neurogenesis and prompted us to develop a novel gene set enrichment analysis approach to identify gene regulatory factors that may orchestrate such a shift. This revealed the significant and universal dysregulation of genes, through therapy, that are targeted by a specific chromatin remodeling machinery. This finding was validated in an independent cohort of 22 further GBM pairs. To understand the therapeutic potential of this finding we must determine whether genes are dysregulated through therapy owing to a) their fixed expression in inherently treatment resistance cells in the primary tumour which get selected during therapy to increase the signal of that profile, or b) changes in expression during the process of cells acquiring treatment resistance. To inspect this, we analysed single cell gene expression data from GBM spheroids pre- and post-treatment. We found that there was significant dysregulation of the genes associated with the chromatin remodeling complex but only at the three-week post-treatment time-point.

CONCLUSION

Our results indicate that GBM cells are being transcriptionally reprogrammed in response to treatment; the mechanism of which may represent a therapeutic opportunity.
OS9.6 Diagnosis of pseudoprogression using FET PET radiomics
Authors: Lohmann P , Elahmadawy M A , Werner J , Rapp M , Ceccon G , Fink G R , Shah N J , Langen K , Galldiks N
Published: September 2019

BACKGROUND

Radiomics derived from different imaging modalities is gaining increasing interest in the field of neuro-oncology. Besides MRI, amino acid PET radiomics may also improve the to date challenging, clinically relevant diagnostic problem of differentiating pseudoprogression (PsP) from tumor progression (TP). To this end, we here explored the potential of O-(2-[18F]fluoroethyl)-L-tyrosine (FET) PET radiomics to discriminate between PsP and TP.

MATERIAL AND METHODS

Thirty-five newly diagnosed IDH-wildtype glioblastoma patients with MRI findings suspicious for TP within 12 weeks after completion of chemoradiation with temozolomide underwent an additional dynamic FET PET scan. FET PET tumor volumes were segmented using a tumor-to-brain ratio (TBR) ≥ 1.6. The static PET parameters TBRmax and TBRmean, as well as the dynamic parameter time-to-peak (TTP), were calculated. For radiomics analysis, the number of datasets for model generation was increased using data augmentation techniques. Subsequently, 70 datasets were available for model generation. Prior to further processing, patients were randomly assigned to a discovery and a validation dataset in a ratio of 70/30, with balanced distribution of PsP and TP diagnoses. Forty-two radiomics features (4 shape-based, 6 first- and 32 second-order features) were obtained using the software LifeX (lifexsoft.org). Afterwards, a z-score transformation was performed for data normalization. For feature selection, recursive feature elimination using random forest regressors was performed. For the final model generation, the number of parameters was limited to three to avoid data overfitting. Different algorithms for model calculation were compared, and the diagnostic accuracy was assessed using leave-one-out cross-validation. Finally, the resulting models were applied to the validation dataset to evaluate model robustness.

RESULTS

Eighteen patients were diagnosed with TP, and 17 patients had PsP. Diagnoses were based on a neuropathological confirmation or clinicoradiological follow-up (26% and 74%, respectively). The diagnostic accuracy of the best single FET PET parameter was 75% (TBRmax). Combining TBRmax and TTP increased the diagnostic accuracy to 83%. Other combinations of static and dynamic FET PET parameters, however, did not further increase the accuracy. The highest diagnostic accuracy of 92% was achieved by a three-parameter model combining the FET PET parameter TTP with two radiomics features. The model demonstrated its robustness in the validation dataset with a diagnostic accuracy of 86%.

CONCLUSION

The results suggest that FET PET radiomics improves the diagnostic accuracy for discerning PsP and TP considerably. Given the clinical significance of differentiating PSP and TP, prospective multicenter studies are warranted.

FUNDING

Wilhelm-Sander Stiftung and the DAAD GERSS Program, Germany
OS12.1 Editing of IDH1 R132H mutation in human induced pluripotent stem cells to investigate tumor genesis in glioma
Authors: Köpp A , Preussler M , Richter S , Heide M , Marrone L , Sterneckert J , Schöler A , Capper D , Schröck E , Klink B
Published: September 2019

BACKGROUND

Low grade gliomas and secondary glioblastomas are characterised by a hot-spot mutation in the Isocitrate dehydrogenase 1 (IDH1). The mutation causes a new catalytic function of the enzyme resulting in the production of 2-Hydroxyglutarat (2-HG), which is known as an oncometabolite. To this day, the pathomechanism by which IDH1 mutation promotes tumorigenesis is not completely understood and the tumour cell of origin for glioma is not known. Moreover, reliable cell models reflecting the patient ́s situation are not available. Thus, we aim at creating human induced pluripotent stem cells (hiPSC) carrying the IDH1 R132H mutation. We will utilize this cell model to investigate how the mutation influences stem cell properties and cell differentiation in neuronal progenitor cells.

MATERIAL AND METHODS

For designing the cell model, we applied the novel CRISPR/Cas9 based genome editing tool Base Editor 3 and 4. We transiently transfected the cells with two plasmids containing the Cas9 enzyme and sgRNA respectively. To determine editing efficiency, cells were investigated using the T7 Endonuclease 1 assay and Next Generation Sequencing. Single cell clones were picked to analyse allele status using allele-specific PCR with subsequent Sanger Sequencing.

RESULTS

Using fluorescence-activated cell sorting we measured a transfection efficiency in iPSCs for one plasmid of 33.8% ± 5.92%. Out of 96 picked clones one clone showed the IDH1 mutation. Thus, the overall editing efficiency was about 1%. We confirmed expression of mutated IDH1 R132H by Western Blot. Measurement of the tricarboxylic acid cycle metabolites using liquid chromatography tandem mass spectrometry (LC-MS/MS) showed a forty times increased concentration of 2-HG in IDH-mutated compared to the wildtype iPSCs, proving that the mutated enzyme is functional. To investigate effects of the IDH1 R132H on cell differentiation, we generated cerebral organoids from our iPSC-models. The IDH1 R132H mutation did not inhibit the cell differentiation in maturation of cerebral organoids. However, we observed differences in the growth between mutated and wildtype brain organoids. We additionally characterized our cell models using genome wide methylation arrays and RNA-Seq; these results will also be presented.

CONCLUSION

We successfully established a heterozygous IDH1 R132H mutated hiPSC cell line, which represents a promising cell model for future studies of early glioma genesis.
OS12.2 Targeting epigenetic pathways in the treatment of recurrent high-grade glioma
Authors: Hau A , Houben L , Klein E , Oudin A , Stieber D , Flies B , Kaoma T , Azuaje F , Fritah S , Bjerkvig R , Hertel F , Mittelbronn M , Golebiewska A , Niclou S P
Published: September 2019

BACKGROUND

High grade glioma (HGG) patients develop resistance to standard treatment leading to disease progression and limited life expectancy. Advances in the molecular characterisation of treatment-naïve HGGs based on next-generation sequencing and DNA methylation analyses have led to a better delineation of HGG subtypes and the identification of distinct genomic abnormalities. Furthermore, using large patient cohorts of longitudinal tumor samples, comprehensive genomic profiling studies emerged to investigate therapy-associated evolution of gliomas. All together, those studies point out the need for personalised treatment strategies, where applied drugs will be adapted to the unique patient-specific genetic abnormalities.

MATERIAL AND METHODS

We collected fresh samples of more than 800 brain tumors containing almost 300 glioma specimen with approximately 100 longitudinal samples of initial and recurrent tumors from 43 matched patients. By now, we have successfully established 34 patient-derived orthotopic xenografts (PDOXs) in mice. We performed comprehensive molecular profiling using array comparative genomic hybridisation, DNA methylation analysis and targeted DNA sequencing on patient specimen and their derivatives such as 3D tumor organoids and PDOXs. The custom-design sequencing panel comprises 234 genes that reflect both established genetic identifiers for individual glioma subtype classification and novel genes encoding mainly epigenetic effector genes. Based on patient-derived material we carried out drug response screening on 3D tumor organoids using a compound library matching the majority of genes that were assessed by targeted sequencing.

RESULTS

We succeeded in generating a live biobank of HGG patient-derived xenografts and 3D organoids that neatly recapitulates the mutational spectrum including structural DNA variation and methylation-based subtypes of gliomas. A highlight is the generation of 19 PDOXs of paired initial and relapse HGGs from a total of 9 glioma patients. A detailed analysis of the paired longitudinal samples indicated that PDOX models closely recapitulate the evolutionary trajectory of the parental tumors. Targeted sequencing of longitudinal HGG PDOXs suggests that relapse tumors accumulate somatic mutations in epigenetic effectors compared with the Initial. Differential drug responses between initial and relapse tumors were observed after screening of in vitro 3D tumor organoids.

CONCLUSION

Response assessment of naïve initial gliomas and recurrences provides crucial information on the differential sensitivity between initial and relapsed HGGs and offers novel personalised therapeutic options in the relapse setting. Furthermore, in depth correlation of the profiled somatic molecular landscape with drug response will enable pharmacogenomic predictions of potential inhibitors in the clinical setting.
OS12.4 In vivo dynamics and targeting of vessel co-option in glioma
Authors: Seano G , Griveau A , Shelton S , Krishnan S , Wang N , Kloepper J , Huillard E , Batchelor T , Stemmer-Rachamimov A , Aghi M , Jain R , Rowitch D
Published: September 2019

BACKGROUND

Gliomas comprise heterogeneous malignant glial and stromal cells. While blood vessel co-option is a potential mechanism to escape anti-angiogenic therapy, the relevance of glial phenotype in this process is unclear.

MATERIAL AND METHODS

Here, we intravitally study preclinical syngenetic models of glioma as well as patient-derived cells transplanted orthotopically. Moreover, we profoundly confirm our preclinical results with histological studies on patient specimens.

RESULTS

We show that Olig2+ oligodendrocyte precursor-like glioma cells invade by single-cell vessel co-option and preserve the blood-brain barrier (BBB). Conversely, Olig2-negative glioma cells form dense perivascular collections and promote angiogenesis and BBB breakdown, leading to innate immune cell activation. Experimentally, Olig2 promotes Wnt7b expression, a finding that correlates in human glioma profiling. Targeted Wnt7a/7b deletion or pharmacologic Wnt inhibition blocks Olig2+ glioma single-cell vessel co-option and enhances responses to temozolomide. Finally, Olig2 and Wnt7 become upregulated after anti-VEGF treatment in preclinical models and patients.

CONCLUSION

Here, we show that glioma is able to employ vessel co-option, i.e. the movement of tumor cells towards and along the pre-existing vasculature.

Glioma oligodendrocyte-like (OPCL) cells express Wnt7 that is necessary for vessel co-option and Wnt inhibitors significantly improve survival with temozolomide. Moreover, we demonstrated that anti-VEGF-treatment of glioma selects for Olig2/Wnt7+ cells
P03.01 Secondary central nervous system lymphoma (SCNSL) in patient with non Hodgkin lymphoma (NHL): a case report
Authors: Susanti E , Suci Rahayu N , Fuad M
Published: September 2019

BACKGROUND

non Hodgkin lymphoma (NHL) is a systemic cancer that originates from lymphocites. Central nervous system lymphoma is a rare form of non Hodgkin lymphoma that involve brain parenchym and spinal cord. The most common type of nervous system involvement is a leptomeningeal metastases. Whereas brain metastases is an extremely rare finding in NHL. We present a case report of NHL patient which metastasized to brain parenchym.

MATERIAL AND METHODS

Case report: a fourty two year old male patient suffered from seizure in September 2018, 7 days prior to hospitalized. severe headache and weakness on the left extremities were found in addition to seizure. A single nodule on the right frontal and another nodules on the right neck region were also found since 7 months ago. Patient was diagnosed with NHL in 2017 after a confirmed biopsy of NHL and underwent a chemotherapy procedure, but uncompleted. After head ct scan procedure in September 2018, which depicted a round mass in frontal lobe, patient underwent a complete chemotherapy procedure with CHOP regimen in September 2018. Another head ct scan was performed in January 2019 after a completed chemotherapy cycle which showed significant decrease in tumour size.

RESULTS

before and after head ct scan showed significant decrease in tumour size, from 4cmx2cm before chemotherapy and 2.5cmx1.3cm after chemotherapy

CONCLUSION

central nervous system involvement in NHL is a rare condition that carries a poor prognosis. Prophylaxis therapy still on debate about it’s efficacy to prevent this disease from spreading or relapse. Awareness of the possibility central nervous system involvement should always remain in a physician’s mind when dealing with NHL patients.
P03.06 Cavernous malformations of the brainstem: radiosurgical management with gamma knife
Authors: Abdel Karim K , El-Shehaby A M , Reda W A , Emad Eldin R M , Nabeel A , Tawadros S , Khalil P
Published: September 2019

BACKGROUND

About 20% of intracranial cavernous malformations (CM) occur in the brainstem. The greatest risk of brainstem CM is hemorrhage which can be devastating and even fatal in this location. The optimal management for these lesions would naturally be microsurgical resection. However, surgery in this location is associated with significant morbidity and mortality. Gamma knife radiosurgery provides a safer alternative. The purpose of this study is to investigate the efficacy of gamma knife radiosurgery for brainstem CM in preventing bleeding, as well as, assess safety with regards to radiation-induced complications. Additionally, we aimed to evaluate the feasibility and safety of volume-staged gamma knife radiosurgery for larger CM in the brainstem.

MATERIAL AND METHODS

Between September 2007 and August 2017, 48 patients with brainstem CM were treated by gamma knife. Thirty-two patients were available for follow up of at least one year. A total of 33 lesions were treated (one patient had two brainstem CM). Twenty-eight patients had at least one hemorrhagic event before radiosurgery. The patients underwent 40 gamma knife sessions. These included 28 single sessions (including two sessions for same patient for 2 different lesions in pons). Five patients had volume-staged gamma knife treatments due to the large size of the CM. The median total CM volume/lesion was 0.8 cc (0.1–30.4 cc), while the median target volume/session was 1 cc (0.1–11.5 cc). The median prescription dose was 12 Gy (10–14 Gy).

RESULTS

The mean follow up after treatment was 40 months (12–95 months). The annual hemorrhage rate (AHR) before gamma knife radiosurgery was 25.5%. After treatment there were a total of 5 hemorrhagic events with an overall AHR of 4.5%. Three hemorrhagic events occurred in the first 2 years after treatment with an AHR of 2.7% and 2 events more than 2 years after treatment with an AHR of 2.2%. No hemorrhagic events occurred among the patients treated by volume-staged radiosurgery. Clinical improvement was observed in 15 (46.9%) patients. Temporary adverse radiation events developed in 6 patients (19%).

CONCLUSION

Gamma knife radiosurgery provides an effective and safe treatment alternative to surgery for brainstem CM. Volume-staged gamma knife radiosurgery for brainstem CM appears to be a viable option for larger CM.
P03.11 Finding a predictive marker for compliance to TTFields therapy - the comptune study
Authors: Proescholdt M A , Haj A , Doenitz C , Brawanski A , Mühlberger A , Schmidmeier M
Published: September 2019

BACKGROUND

Tumor Treating Fields (TTFields) imply the administration of alternating electric fields to induce mitotic arrest in Glioblastoma (GBM) cells. Based on the specific mode of action, which requires continuous exposure of the malignant cell pool to TTFields, compliance to TTFields treatment is a crucial parameter for treatment success. Correspondingly, a recent post hoc analysis of the EF-14 trial has demonstrated a strong correlation between TTFields compliance rate and treatment success. However, there is currently no data regarding predictive factors for individual compliance rate. We are therefore performing a prospective study designed to analyze specific parameters potentially influencing compliance to TTFields treatment employing a standardized psychological assessment battery in GBM patients who choose or not choose to undergo TTFields treatment in a longitudinal fashion. The results of the psychological profile will be correlated to the compliance rates of the individual patients.

MATERIAL AND METHODS

Forty adult patients treated for newly diagnosed GBM at the University Regensburg Medical Center will be recruited. The psychological assessment battery aims at assessing four categories relevant for treatment compliance: 1. Lack of communicative skills, 2. depressive and anxiety disorders, 3. interpersonal factors (e.g. social support), and 4. intrapersonal factors, (e.g. beliefs about benefit, self-efficacy). The study endpoints are: 1. willingness to undergo TTFields therapy and 2. compliance rate of the individual patient, provided by the technical support team. The first interview takes place after treatment consultation (T0), 2 weeks after diagnosis (T1), at the initiation of TTFields treatment (T2) and every 4 weeks during treatment either until second disease progression or after maximal 8 months observation time per patient. Additionally, demographic (gender, age, marital status), clinical (KPI, extent of resection) and biological factors (MGMT promoter status, IDH1 mutation) will be assessed.

RESULTS

The study has been approved by the local ethics committee and has recruited the first 23 patients within 8 months since initiation of the study. The most updated results will be presented at the meeting.

CONCLUSION

One of the most challenging aspects in the application of TTFields in clinical practice is the identification of influencing factors increasing patients’ compliance. This study is designed to provide a psychological profile predictive for high treatment compliance.
P04.03 Radiotherapy for subependymal giant cell astrocytoma: time to challenge a historical ban? Case report and review of the literature
Authors: Kamel R , Van den Berge D
Published: September 2019

BACKGROUND

Subependymal giant cell astrocytoma (SEGA) is a low-grade glioma that occurs in patients with tuberous sclerosis complex (TSC). SEGA typically grows within the ventricles causing hydrocephalus and sudden death. Surgical resection is the traditionally preferred treatment and expert opinion advises strongly against the use of radiotherapy, insomuch that it is not even mentioned as a treatment option in reviews or guidelines. Nevertheless, surgical resection of big volume or bilaterally growing SEGA can be very challenging. Recently, success has been reported with the use of mTOR inhibitor, everolimus, in reducing tumor volume. However, regrowth was observed after drug cessation requiring long-term if not life-long drug administration and thus raising concerns regarding side effects and high treatment costs. Here, we report about a case with inoperable bilateral SEGA that was successfully treated with fractionated stereotactic radiotherapy alone (30x2Gy) with a follow up period of 8 years before being treated with everolimus for renal involvement of TSC. Currently, the patient has been followed up for 13 years.

MATERIAL AND METHODS

All of the patient’s pre and post treatment MRI’s were used for detailed volumetric assessment of the response of the SEGA on each side separately. Systematic review of the literature was conducted via PubMed and Up-to-date using the search terms: ‘treatment of SEGA’, ‘radiotherapy in SEGA’, ‘SRS in SEGA’, ‘treatment of tuberous sclerosis complex’, ‘radiotherapy treatment in low grade astrocytoma’, etc. The article references were queried for the terms ‘radiotherapy’, ‘induced tumors’ and ‘malignant tumors’. Secondary references were added to the database and reprocessed similarly. Reviews about radiation-induced tumors were also added to the database. Attention was given to reports containing data about irradiated SEGA and about high-grade brain tumors in TSC patients. The database was locked on 1-02-2018 containing 1298 article references and 780 full-text articles.

RESULTS

In our case, the successive volumetric assessments on MRI’s demonstrated 80% volume reduction after radiotherapy alone, further enhanced to 90% after everolimus administration. Literature review shows no valid evidence for contra-indicating fractionated stereotactic radiotherapy in SEGA and shows that surgery is still associated with high re-operation and post-operative complications rates.

CONCLUSION

A slow progressive response of SEGA on both sides to radiotherapy was observed similar to the response seen in other benign intracranial tumors. We believe that stereotactic radiotherapy alone or sequentially combined with everolimus deserves to be studied as an alternative to resection in difficult cases that do not require immediate volume reduction.
P04.05 The Effects and Mechanism Involved in Paclitaxel combined with Shikonin on U87 Glioma Cells
Authors: SHI J
Published: September 2019

BACKGROUND

Glioma is the most common intracranial primary tumor,chemotherapy seems to be the main treatment for brain glioma.Chemotherapy is currently widely used in clinical treatment of gliomas,however,drug-resistant always appears,so combination of chemotherapy has became an inevitable choice. Paclitaxel and shikonin are stable and efficient chemotherapy drugs which can promote apoptosis and ininhibite the growth of tumor.Recent research reports,paclitaxel and shikonin can respectively activate and inhibit the expression of p-ERK.The purpose of this study was to investigate whether we can inhibite the activation of p-ERK caused by paclitaxel to enhance the effect of paclitaxel,furthermore use the combination of the two drugs to reach a better effect of chemotherapy.

MATERIAL AND METHODS

1.Cell Culture2. Drugs Administration.3. Growth Inhibition Assays (CCK-8) .4.Scratch test to observe cell migration 5.Transwell assay for the determination of cell migration 6.Transwell assay for the determination of cell invasion 7. Annexin V-FITC and PI Assay for Flow Cytometry to Detect Apoptosis 8. PI Assay for Flow Cytometry to Detect Cell Cycle 9. Western Blot to Detect the Expression of P-ERK/ERK 10. Statistical Analysis.

RESULTS

1.The results tested by CCK-8 showed these two drugs have synergic effects with a CDI equals to 0.72 which means these two drugs are significant synergistic.2.Compared with paclitaxel group or shikonin group,the 1/2paclitaxel+1/2shikonin group had a significant inhibitory effect upon the migration of U87 cells.3.Compared with paclitaxel group and shikonin group,the 1/2paclitaxel+1/2shikonin group had a significant inhibitory effect upon the invation of U87 cells.4.Compared with paclitaxel group and shikonin group,the 1/2paclitaxel+1/2shikonin group had a significant promoting effect upon inducing apoptosis of U87 cells.5. The 1/2paclitaxel+1/2shikonin group significantly improved the apoptosis rate of U87 cells,the RNA content of the G1-phase was significantly increased in shikonin group, the RNA content of the G2- phase significantly increased in paclitaxel group and 1/2paclitaxel+1/2shikonin group.6.Compared with control group,the rate of p-ERK/ERK was increased in paclitaxel group(P<0.05),while the rate of p-ERK/ERK was significantly decreased in the shikonin group and 1/2paclitaxel+1/2shikonin group(P<0.05).

CONCLUSION

1. Compared with paclitaxel group and shikonin group,the combination group with half dosage can make synergic effects and significantly inhibit the proliferation,migration and invation ability of U87 cells,besides promote apoptosis of U87 cells and block U87 cell cycle.2. Paclitaxel combined with shikonin could decrease the expression of p-ERK/ERK,which may be involved in the synergic effects of these two drugs.
P04.06 The incidence and impact of post-operative stroke in surgery for LGG
Authors: berger A , Tzarfati G , Costa M , Serafimova M , Korn A , Alfasi T , Kashinian A , Ram Z , Grossman R
Published: September 2019

BACKGROUND: INTRODUCTION

Postoperative neurological deficits may outweigh the benefit conferred by maximal resection of gliomas. Ischemic complications are a common cause of such deficits. In this study, we evaluated the incidence of ischemic events in patients undergoing surgery for low-grade gliomas (LGG) and the long-term neurological and cognitive implications of those events.

METHODS

Between 2013–2017, 168 patients underwent surgical resection or biopsy for LGG at our center. A full dataset, including pre- and postoperative magnetic resonance imaging (MRI) and long-term clinical evaluation findings, was available in 82 patients that underwent resection, and they comprised our study cohort. We retrospectively analyzed pre- and postoperative demographic, clinical, radiological, anesthetic, and intraoperative neurophysiology data to characterize associated ischemic complications. Overall and progression-free survival, as well as functional and neurocognitive outcomes were evaluated as well.

RESULTS

The immediate postoperative MRI showed evidence of an acute ischemic stroke adjacent to the tumor resection cavity in 19 patients (23%), 13 of whom developed new neurological deficits as a result of the ischemic event. Infarcts were more common in patients undergoing surgery for a recurrent tumor, especially those involving the Sylvian fissure (p<0.05). Surgery for insular gliomas had the strongest association with postoperative infarcts (multivariate analysis: odds ratio =12.4, 95% confidence interval 2.21–69.8). There was no difference in survival between patients with or without a postoperative infarct. The median Karnofsky Performance Status was lower for the infarct group compared to the non-infarct group at 3 months after surgery (p=0.016), with a gradual significant improvement for the former over one year of follow-up (p=0.04). Immediately after surgery, 27% of the patients without infarcts and 58% of those with infarcts experienced a new motor deficit (p=0.037), decreasing to 16% (p=0.028) and 37% (p=0.001), respectively, at one year. Neurocognitive analysis findings before and 3 months after surgery were unchanged, but there was a significant decrease in naming in patients who experienced an infarct (NeuroTrax computerized battery score of 100±9 and 83±19, p=0.04 respectively). Confusion during awake craniotomy was a strong predictor of the occurrence of an ischemic stroke.

CONCLUSIONS

Intraoperative strokes are more prevalent among patients who undergo recurrent surgeries, especially procedures in the insula. Although they do not affect survival, these strokes negatively affect the patients’ activity and performance status, especially during the first 3 postoperative months, with gradual functional improvement over one year.
P04.15 Impact of histone lysine methyltransferases SETDB1, SETD2, SUV39H1, MLL2, EZH2and their corresponding histone marks in pediatric astrocytomas
Authors: Klonou A , Korkolopoulou P , Gargalionis A N , Themistocleous M , Sgouros S , Papavassiliou A G , Piperi C
Published: September 2019

BACKGROUND

Pediatric brain tumors are characterized by altered epigenetic profiles and deregulated chromatin remodelling that affects gene expression. Histone lysine methylation has emerged as important chromatin function regulator, with potential role in glioma formation. Τhis study investigates the expression of histone lysine methyltransferases (SETDB1, SUV39H1, EZH2, MLL2, SETD2) and their corresponding methylation marks (H3K9me3, H3K27me3, H3K4me2/3, H3K36me3) in pediatric astrocytomas.

MATERIAL AND METHODS

Thirty-four (34) archival pediatric astrocytomas [27 low grade (I/II) and 7 high grade (III/IV) tumors; 21 males, 13 females; 1–15 years old] and 5 postmortem normal brain samples were studied. Methyltransferases expression and histone marks were detected by immunohistochemistry as H-score (intensity multiplied with cell percentage, 0–300) and validated by western blot.

RESULTS

Elevated nuclear SETD2 and SETDB1 staining was observed in all astrocytomas (median H-score:165 and 110, respectively). SETDB1 and SETD2 expression levels were positively associated (p=0.004), being higher in high grade compared to lower grade tumors (p=0.001, p=0.027, respectively). Furthermore, SETDB1 staining was significantly increased in male children (p=0.051) and negatively associated with patients age (p=0.028). A moderate nuclear and cytoplasmic staining was obtained for MLL2 at low grade (median H-score:84) compared to high grade tumors (median H-score:144). In accordance, lower SUV39H1 nuclear and cytoplasmic expression was detected in low grade tissues (median H score:85) compared to high grade (median H-score:160). EZH2 presented no significant nuclear expression. Increased nuclear staining of H3K9me3 and H4K20me3 repressive marks was observed in astrocytomas (median H-score:297 and 270, respectively), being positively associated (p=0.02). Elevated nuclear staining of H3K4me3 active mark (median H-score:210) was detected in astrocytomas, being significantly higher in high grade tumors (p=0.025) and in male children (p=0.036).

CONCLUSION

SETDB1, SETD2, SUV39H1 and MLL2 may play a significant role in modulating gene expression in pediatric astrocytomas. Increased presence of H3K9me3, H4K20me3 and H3K4me3 histone marks signifies their possible participation in gliomagenesis.

Larger cohort studies need to elucidate the functional significance and underlying molecular mechanisms of these chromatin-modifying enzymes and respective histone changes in pediatric astrocytomas.
P06.02 Tumor Treating Fields therapy application in 3-year-old grade 4 glioma patient is feasible and safe
Authors: Kietz S , Stein M
Published: September 2019

BACKGROUND

High-grade gliomas (HGG) are aggressive brain tumors affecting both children and adults. In adult patients a new treatment modality was recently established for patients with newly diagnosed (nd) and recurrent glioblastoma (GBM). Low intensity intermediate frequency alternating electric fields, known as Tumor Treating Fields (TTFields), demonstrated significantly increased survival rates in combination with adjuvant temozolomide (TMZ) in adult ndGBM patients. For pediatric HGG patients only few treatment options are available. Here, we report on a pediatric patient who is receiving TTFields therapy in combination with temozolomide.

MATERIAL AND METHODS

A three-year-old male presented with a grade IV glioma with H3K27M expression located pontine on the right occipital. A stereotactic biopsy was performed; further analysis revealed no IDH1 mutation, no TERT promoter mutation and no MGMT promoter methylation. The patient recieved radiochemotherapy with temozolomide. TTFields therapy was initiated after completion of radiochemotherapy in combination with temozolomide. Due to the location of the tumor, the infratentorial transducer array layout was used for TTFields application.

RESULTS

At the beginning of TTFields therapy the patient and his family needed time to get used to the new therapy, due to this the adherence to TTFields therapy was on a low level in the first month. The TTFields usage rate improved every month from about 40 % in the first two months to about 80 % after 5 and 6 months. After the initial time for adaption to the therapy, the average usage rate in months 4 to 8 was 75.87 %, which is above the independent prognostic threshold of 75 %. The patient is on TTFields therapy for more than 8 months and no therapy-related adverse events were observed during this time. To-date the patient is still on TTFields therapy and clinically stable. MRI analysis revealed stable disease with a slightly reduced area of contrast-enhancement.

CONCLUSION

In this case, the TTFields usage rate was low in the beginning, the patient and his relatives demonstrated a successful adaption to the therapy over time. This case demonstrates that TTFields therapy can be continued at high adherence, although the usage rate might be low in the beginning. Moreover, in this presented patient TTFields therapy is feasible and safe in a pediatric patient at 3 years of age at initiation of therapy. In conclusion, TTFields therapy can be offered to pediatric patients with HGG. Safety and efficacy in pediatric patients should be further investigated in clinical trials.
P08.02 Israeli experience with Patient Reported Outcomes (PROs) in the field of neuro oncology - Quality of Life Assessment Metrics (QAM)
Authors: Wagner T , Jan E , Bley S , Cohen R , Furman O , Talianski A , Zach L
Published: September 2019

BACKGROUND

With the development of personalized medicine, it is necessary to take into consideration PROs, including quality of life (QOL) to adjust the treatment and follow up. Trends of QOL outcomes are of special interest for neuro oncologic patients in the setting of chemo-radiotherapy due to the high incidence of pseudo progression (worse MRI with no tumor progression). There are several QAM in the field of neuro oncology. We used the quality of life questionnaire (QLQ-30) for brain cancer with the QLQ-BN20 supplement, and Functional assessment of chronic illness therapy (FACIT) with the FACT-Br supplement (version 4). We looked at the level of agreement between the two assessment tools for QAM for Israeli patients with different brain tumors.

MATERIAL AND METHODS

Forty patients were recruited between September 2017 to May 2018 at Sheba Medical Center after local IRB approval. Patients fulfilled the two types of questionnaires at 4 time points: before radiotherapy, with radiotherapy completion, at three months follow up and before another intervention. The difference between the two metrics was measured by t-test and performed by Bland-Altman plot. The association between QAM and MRI after radiotherapy and doctor assessment was measured by Linear regression.

RESULTS

Forty patients completed 162 questionnaires overall (QLQ-30 and FACIT): 8 patients completed questionnaires at all 4 time points, 7 patients completed questionnaires - 3 times, 6 patients- twice, and 19 patients- once. Three patients didn’t answer FACIT questionnaires and 3 other patients didn’t answer QLQ questionnaires. Patients population included 40% (16/40) with astrocytoma [25% (4/16), 31.2% (5/16), 43.8% (7/16) of them with WHO Grade 2,3,4 respectively], 25% (10/40) with meningioma [60% (6/10), 20% (2/10), and 20% (2/10) of them with WHO Grade 1,2 and 3 respectively], 20% (8/40) with brain metastasis, and other tumors (6/40) consisted 15% of the patient population. We found a significant difference between QAM means of agreement of the two metrics used (p<0.001). There was a significant correlation between QAM and MRI after radiotherapy (p=0.013; R2=0.369 and p=0.025; R2=0.292 for QLQ and FACIT questionnaire, respectively). There was no significant correlation between physician examination and QAM metrics (p=0.880; R2=0.002 and p=0.724; R2=0.009 for QLQ and FACIT questionnaires respectively).

CONCLUSION

Patients’ evaluation success depends on the appropriate assessment metrics. QLQ questionnaires were a more appropriate tool in our patient population confirmed by MRI assessment compared to physicians’ evaluation. Our study shows a significant difference between two well validated tools. Further research is needed to establish the source of this difference and adjust QAM for neuro oncologic patients accordingly.
P09.01 case series: meningioma in young adult male
Authors: Diansari Y , Karindang N , Anggraeni D
Published: September 2019

BACKGROUND

Intracranial meningiomas are most common among patients in their fifth to seventh decade of life, typically found in older women. Meningiomas are rare in children and young adults; they represent 1–3% of all intracranial tumors in individuals up to age 20 years and 13.5% of intracranial tumors in the 20–34 age group. Meningioma in young adult male is a rare finding. Management of meningioma is similar between young or older patient. The prognosis is depent on the histology finding and type of resection. This case series was made to report an uncommon case including clinical characteristic and management of meningioma in young adult male.

MATERIAL AND METHODS

We reported 2 cases of meningioma in young adult male. The first patient was hospitalized on 2016 and diagnosed with atypical meningioma (WHO grade II). The second patient was hospitalized on 2018 and diagnosed with trantitional meningioma (WHO grade I).

RESULTS

First case: 23 y.o male was hospitalized because of severe headache. His physical exam showed weakness of his left side of the body. There was diplopia that significant for bilateral six nerves palsy. Funduscopy examination revealed papil edema in both eyes correlated with his complained of blurry visions. There was no cranial irradiation from his past medical history. Second case, a male 22 y.o was because of decreased of visual acquity progressively since two month before. There was history of throbbing headache in his left head with mild to moderate intensity. On his neurological examination, there was mild weakness in his right body side. Visual acquity on his right and left eyes were 1/300 and 1/60. Bilateral papil edema was found in funduscopy examination. In his past medical history, there was no history of cranial iradiation. Both cases showed similar initial symptoms consist of headache and others neurological deficit. Radiological examination was performed with result leading to meningioma in convexity area in both cases. Craniotomy tumor removal with gross total resection as simpson grade 2 was achieved in both patients. In the second case pre-operative embolization was performed in order to achieve optimal resection. Histopathology examination confirmed as atypical (WHO grade II) in the first case and trantitional Meningioma (WHO grade I) in second case. Follow up imaging post operation showed no residual mass lesion in both patients. There were no further management in these patients. Both of patients showed improvement in their neurologic function and able to activity without restriction in daily living. Serial imaging examination is planned to observe reccurence of the tumor.

CONCLUSION

Clinical presentation and management of meningioma in these patients are similar as meningioma commonly. Both of patients showed clinical improvement after craniotomy tumor removal succesfully.
P09.08 Increased incidence of intracranial meningiomas in patients with acromegaly
Authors: Engelhardt J , Nunes M , Pouchieu C , San-Galli F , Gimbert E , Vignes J , Laurent F , Berge J , Baldi I , Tabarin A , Loiseau H
Published: September 2019

BACKGROUND

An increased incidence of various neoplasms has been described in patients with acromegaly and there is evidence to suggest that growth factors are risk factors for the development of meningiomas. We aimed to study if patients with acromegaly are more at risk for developing intracranial meningiomas

MATERIAL AND METHODS

We conducted an observational study on 221 consecutive acromegalic patients recruited between January 1, 2000 and December 31, 2015, and 357 consecutive patients with a non-somatotropic pituitary adenoma recruited between March 1, 2015 and December 31, 2016 in our institution. Patients underwent a gadolinium-enhanced 3D T1 brain MRI to look for meningiomas. The proportion of meningiomas was compared between the two groups and the standardized incidence ratio (SIR) was computed from the incidence rates of meningiomas observed in the population of acromegalic patients and compared to that of the general population given by the local registry of central nervous system tumors.

RESULTS

Patients with acromegaly had a significant risk for developing intracranial meningiomas as compared to patients without acromegaly (7.7% vs. 2.2%, p = .005, OR = 3.45 [1.46; 8.15]). There was a significant increased incidence of intracranial meningiomas in patients with acromegaly (SIR = 126 [25; 367]) as compared to the general population.

CONCLUSION

Our study provides the first evidence that patients with acromegaly are more at risk for developing intracranial meningiomas.
P10.03 Immunological differences between patient-matched normal-derived and GBM-derived pericytes
Authors: Macapagal J , Brooks A , Schweder P , Mee E , Faull R , Park T I H , Dragunow M
Published: September 2019

BACKGROUND

Glioblastoma Multiforme (GBM) is the most aggressive, fatal, yet most common form of brain malignancy in adults. Despite advances in immune-based treatments for other modes of cancer, GBM remains a challenge due to its ability to dampen immune responses via mechanisms not yet fully understood. With a median survival time of only 15 months following diagnosis, there is a strong push to find new targets for therapy. The microenvironment comprises a mixture of malignant tumour cells, stroma, blood vessels and infiltrating inflammatory cells. Despite advances in understanding the contribution of these cells in establishing an anti-inflammatory microenvironment, the contribution of pericytes, an important neurovascular mural cell that forms the blood-brain barrier, has been inadequately studied. Therefore, we investigated the differences in immune profile between patient-matched non-neoplastic brain- and GBM-derived pericytes under basal and induced conditions.

MATERIAL AND METHODS

Primary patient-matched non-neoplastic brain and GBM tumour derived pericytes were isolated from specimens excised from consenting patients undergoing GBM surgical resection at Auckland City Hospital. Pericytes were treated with inflammatory cytokines including IL-1β, IFN-γ, TNFα and TGFβ for up to 24 hours. Inflammatory profile changes were probed for using fluorescent immunocytochemistry, qRT-PCR and spectral flow cytometry. Media was also collected for secretome analysis via cytometric bead array.

RESULTS

GBM pericytes show decreased expression of CX3CL1, both basally and following IL-1β treatment, via qRT-PCR and CBA. In contrast, increased gene expression and secretion of IL-6 and IL-8 by GBM pericytes were observed. GBM pericytes also basally express CD90 and anti-inflammatory molecule PD-L1 compared to their normal counterparts. In terms of activated pathways, basal SMAD2/3 activation is increased in GBM pericytes, while also showing greater activation following treatment with IL-1β, IFN-γ but not TNFα. C/EBPδ is activated and translocated following inflammatory stimulation; however, shows localised expression within the cytoplasm only observed in GBM pericytes.

CONCLUSION

This immunological screen of GBM pericytes highlights them as key players in the establishment of the tumour microenvironment. With data suggesting the activation of pathways such as the SMAD2/3 pathway in an unconventional manner, it suggests the potential for pericytes to manipulate pathways towards a more immunosuppressive outcome. Further immune characterisation of such cells is required to fully understand how they might contribute to the immunosuppressive nature of GBM.
P10.05 NKG2DL expression and dormancy in cerebral metastases: impact of chemotherapeutic treatment
Authors: Flueh C , Hufnagel R , Synowitz M , Held-Feindt J
Published: September 2019

Background: Cerebral metastases are common intracranial lesions and have enormous prognostic impact. In many cases, brain metastases seem to be insensitive to chemotherapeutic treatment and are often source of recurrence. To date, the reasons for this are not entirely known. Dormant tumor cells are a population of non-apoptotic, low proliferating cells, which have the ability to be reactivated and can be the source of recurrence. Another mechanism of tumor cell survival are immunological escape mechanisms, involving the Natural Killer Group 2, member D (nkg2d) receptor-ligand system. In a previous study we were able to show that human brain metastases of pulmonary and breast cancer harbor a significant amount of dormant tumor cells, which often coexpress NKG2D ligands. We now wanted to investigate, whether chemotherapeutic treatment has an effect on expression of dormancy markers and nkg2d ligands.

Materials and Methods: The murine breast cancer cell line E0771 and the murine pulmonary cancer cell line LLC were treated with ascending doses of cisplatin and cyclophosphamid, two chemotherapeutics which are also used in humans, for 2 to 10 days in comparison to negative controls. We performed a cytotoxicity assay. Expression of the dormancy-associated markers pdgf, fgf2, hif1alpha, epha5, h2bk and igfbp5 and the nkg2d ligands mult1, h60a, h60b, h60c and raet1b were analyzed by qrtPCR and immunocytochemistry (IHC).

Results: Cytotoxicity assay revealed, that cells from both lines died significantly after treatment with Cisplatin in comparison to control conditions. Whereas cyclophosphamide had no effect on dormancy marker and nkg2dl expression, treatment with cisplatin led to a significant upregulation of many nkg2dl and dormancy marker expression in LLC and E0771 in a dose and time dependent manner. Results were confirmed via IHC.Conclusions: Although chemotherapy with cisplatin leads to death of many cells in culture, the surviving cells show a high expression of dormancy markers and of certain nkg2d ligands. Not only acquisition of dormancy but also nkg2d ligand expression might play an important role in chemoresistance of brain metastases. Markers from both groups could therefore be effective therapeutic targets.