tbuckley/cabot-search huggingface dataset:
PATH-61. A NOVEL ANALYSIS MODEL OF MGMT METHYLATION PYROSEQUENCING OFFERS AN OPTIMAL PREDICTIVE PERFORMANCE IN GLIOMAS
Authors: Ruichao Chai, Yongzhi Wang, Yuqing Liu, Kenan Zhang, Fan Wu, Tao Jiang
Journal: Neuro-Oncology (2018)

The MGMT methylation is crucial for clinical decision-making in gliomas. MGMT pyrosequencing results were often dichotomized based on a threshold value for the average methylation of several tested CpGs. However, the frequent ‘gray zone’ results of this method immersed physician in a dilemma, and a novel analysis model which could address this issue is urgently required. In this study, we confirmed the MGMT promoter CpGs heterogeneity in 213 high-grade gliomas from two experimental cohorts, which included the seven-site cohort and the eight-site cohort with CpGs 72–78 and CpGs 75–82 tested, respectively. The optimal cut-off value of the methylation status for different CpGs also varied from 4% to 16%. Thus, we raised a novel analysis model, which comprehensively considered each individual CpGs methylation status with its own cut-off value determined by ROC, and the novel analysis defined MGMT promoter methylation when ≥ 3 CpGs exceeded their respective optimal cut-off values. Then we evaluated the predictive accuracy of the novel analysis model in 135 patients received temozolomide from the two experiment cohorts. The results were also validated in an independent cohort including 65 patients, and further compared with the methylation-specific PCR (MSP) approach. In all three cohorts, the novel analysis for CpGs 75–78 accurately predicted the therapeutic prognosis of patients whose methylation levels in the ‘gray zone’, and improved the AUCs from (0.67, 0.76, and 0.67) to (0.70, 0.84, and 0.72), respectively. Moreover, the advantages of the novel analysis were demonstrated regardless of WHO grades and IDH status. The novel analysis was superior to MSP testing in the validation cohort. Taken together, the novel analysis model offers an optimal clinical predictive performance of MGMT pyrosequencing results, and it is suitable for clinical practice in gliomas.
RARE-18. OSTEOSARCOMA AND MEDULLOBLASTOMA IN A LI-FRAUMENI PATIENT
Authors: Ronald Hamilton, Bassem Razzouk, Terence Cudahy, Daniel Fulkerson, Jason Chiang, Diana Thomas
Journal: Neuro-Oncology (2018)

Li-Fraumeni patients have germline mutations in the TP53 gene resulting in increased risk of developing one or more malignant tumors. In children, osteosarcomas and rhabdomyosarcomas are the most common tumors outside the central nervous system (CNS). Primary CNS tumors in these patients include glioblastomas, choroid plexus carcinomas and medulloblastomas. We present an unusual case of a 15 year old boy who had a left tibial osteosarcoma resected 4 years ago, then treated with chemotherapy, without any recurrence or metastatic disease. His two younger male siblings both have the same mutation, and one sibling has already developed an osteosarcoma. Interestingly, the mutation is present in the mother, who has no neoplasm to date. Annual radiological studies of the CNS were normal until February 2017; but it was 13 months until the next scan, which revealed a large tumor in the lateral cerebellum. The patient was asymptomatic and a surgical resection was performed. The operative report described a well-circumscribed mass in the lateral cerebellum with little parenchymal involvement bringing up the possibility of metastatic disease. Neuropathological evaluation showed a densely cellular tumor with large and markedly pleomorphic nuclei as well as numerous mitoses. No cerebellar tissue was seen. Immunohistochemical (IHC) studies were complicated by the widely overlapping antigenicity of osteosarcomas and medulloblastomas. Next Generation Sequencing found abnormalities in SMO, DDX3X, TP53, and MYCN amplification, which are associated with SHH-activated medulloblastomas. Both GAB1 IHC and FISH studies for YAP1 were positive. In summary we report a rare case of an SHH-activated medulloblastoma, large cell/anaplastic type in a 15 year-old boy with a germline TP53 mutation and history of resected osteosarcoma.
TMOD-05. GLIOMA-261 LUCIFERASE-EXPRESSING CELL LINE STIMULATES AN IMMUNOGENIC RESPONSE SIGNATURE IN AN IMMUNOCOMPETENT MURINE MODEL
Authors: Victoria Sanchez, John Lynes, Gifty Dominah, Xiang Wang, Arnold Obungu, Stuart Walbridge, Nancy Edwards, Edjah Nduom
Journal: Neuro-Oncology (2018)

Immunocompetent murine models of glioma, such as GL261, are essential to assess immune therapy efficacy. The GL261 cell line expressing firefly luciferase (GL261RFluc), has been used to enable non-invasive tumor monitoring in preclinical studies. However, it is unclear if the GL261 and GL261RFluc cells are equivalent, particularly when applied to tumor immunology. C57BL/6 mice (n=20 per group, repeated once) underwent stereotaxic, intracranial implantation with GL261 or GL261RFLuc cells at 5x10^4cells/5uL and were assessed for survival. GL261 and GL261RFluc cell lines were assessed by CFSE proliferation assay. TGF-Beta2 ELISA and proteome profiler immunoassay were performed on equivalent cell culture lysates for cytokine analysis. Mice were implanted with GL261 or GL261RFluc cell lines, sacrificed at day 10, and brains were either disassociated, FACS stained, and sorted for immune cell surface antigens (n=4 each group) or formalin-fixed and paraffin embedded for immunohistochemistry (IHC, n=6 each group). Median survival for GL261 implanted mice was 20.9 ± 1.3 days with all animals progressing to a moribund state, while median survival was not reached for animals implanted with GL261RFluc cells (P=0.001). Quantitative IHC analyses of brains implanted with GL261RFluc cells showed significant increases in CD4 and CD8 cells but decrease in FoxP3 positive cells. Proliferation assays were equivalent. TGF-Beta2 ELISA showed significantly elevated levels in the GL261RFLuc cells. Proteomic profiler results demonstrated differential cytokine expression greater than 2-fold for over 25% of cytokines evaluated. The detected increases in chemoattractants CCL2 and CCL5 were particularly pronounced in GL261RFLuc cells. FACS analysis showed a trend of increased PD-L1 positive cells in brains implanted with GL261 cells, but this did not reach significance. GL261RFluc cells create an inflammatory immune microenvironment when implanted intracranially in C57BL/6 mice compared to GL261 cells. These findings suggest that investigators should avoid GL261RFluc cells when evaluating immune therapeutics in a C57BL/6 background.
COMP-22. LARGE SCALE TRANSCRIPTOMIC ANALYSIS OF MELANOMA BRAIN METASTASES
Authors: Jeanne Kowalski, Daniel Pomeranz Krummel, Manali Rupji, Bhakti Dwivedi, Havva Keskin, Laura Kallay, Maxwell Xu, Alexandra Ross, Robert Press, Havi Rosen, Erin Connelly, Rikesh Patel, Benjamin Izar, Cory Adamson, Jeffrey Olson, Jing Su, Ragini Kudchadkar, Matthew Schniederjan, Lindsey Lowder, Stewart Neill, Walter Curran, David Lawson, Michael Chan, Mohammad Khan, Soma Sengupta
Journal: Neuro-Oncology (2018)

Brain metastases are the most common cause of adult brain tumors and highly challenging to treat. Additionally, melanoma brain metastases carry a particularly poor prognosis, with a median overall survival of 4–5 months. Standard-of-care treatment of brain metastases includes surgery, radiation, and chemotherapy. However, melanoma is a radio-resistant cancer, thus significantly limiting options for treatment of its metastasis to the brain. There is clearly a significant demand for new treatment approaches. We are conducting a large scale, whole transcriptomic analysis of melanoma brain metastases to provide insight into molecular changes that may contribute to metastasis as well as to identify potential therapeutic targets of the metastasized cancer. Total RNA was extracted from >50 melanoma brain metastases formalin-fixed paraffin-embedded (FFPE) samples and libraries constructed and enriched for coding region transcript fragments. Libraries were subjected to Transcriptome Capture (TCap) targeting 21,415 genes, which represents greater than 98% of the RefSeq exome, and sequenced using the Illumina HiSeq platform. Preliminary transcriptomic analysis of melanoma brain metastasis samples reveals that ion channel expression manifests as a prominent feature in metastatic melanoma and that in some cases correlates with poor clinical outcome. Greater than 20% of FDA approved drugs target ion channels. We report that repurposing of one such class of drugs targeting the ligand-gated neurotransmitter GABAA receptors can impair melanoma cell viability. We will report on differential expression analysis between recent melanoma transcriptomic studies1,2 and melanoma brain metastases samples and correlation of expression with primary melanoma DNA variants as well as potential therapeutic targets based on anomalous expression of protein coding genes, including of ion channels. References: 1Akbani, et al. (The Cancer Genome Atlas Network, TCGA). Genome classification of cutaneous melanoma. Cell 2015; 161(7): 1681–1696. 2Tirosh, et al. Dissecting the multicellular ecosystem of metastatic melanoma by single-cell RNA-seq. Science 2016; 352 (6282): 189–196.
ACTR-46. HIGHER DOSES OF TTFIELDS IN THE TUMOR ARE ASSOCIATED WITH IMPROVED PATIENT OUTCOME
Authors: Matthew Ballo, Zeev Bomzon, Noa Urman, Gitit Lavy-Shahaf, Steven Toms
Journal: Neuro-Oncology (2018)

INTRODUCTION: It has been suggested that increasing Tumor Treating Fields (TTFields) dose to the tumor leads to better patient outcome. However, this hypothesis has yet to be demonstrated. Here we present a first-of-its-kind study testing this hypothesis using data collected during the EF-14 trial that demonstrated the clinical benefit of combining TTFields with chemoradiation in newly diagnosed glioblastoma patients. Patients treated with TTFields for at least 2 months for whom baseline MRI quality was sufficient for creation of a computational model were included in the study (n=317). The patients transducer array layouts, average compliance (fraction of therapy time), and the average electrical current derived from TTFields generator logs, were collected. Based on these data, realistic computational simulations of TTFields delivery to the patients were performed. Local Minimum Dose Density (LMiDD) was defined as the lower of the power densities delivered by two roughly orthogonal electric fields to each point in the model, multiplied by the average compliance of the patient. The average LMiDD (within a tumor bed combining the tumor and a 3 mm wide zone around it) was calculated. A value of average LMiDD that divided the patients into two groups with the most statistically significant difference in median OS was sought. The optimal threshold of average LMiDD was equal 1.6 mW/cm3 OS (25.1 months vs. 20.9 months, p=0.002, HR=0.69); PFS (8.8 months vs 6.5 months, p=0.006 HR=0.66). Prognostic factors in both groups were similar. The median OS and PFS were also longer when average electric field in the tumor bed was >1.05 V/cm OS (25.0 months vs. 21.6 months, p=0.043, HR=0.76) and PFS (8.1 months vs 7.9 months, p=0.006 HR=0.74). This study utilizes clinical data to demonstrate the connection between TTFields dose and efficacy, emphasizing the importance of TTFields treatment planning for improving patient outcome.
TMIC-34. Na/H EXCHANGER ISOFORM 1 (NHE1) IN IMMUNOSUPPRESSIVE TUMOR MICROENVIRONMENT IN MOUSE SYNGENEIC GLIOMA MODEL
Authors: Nabiul Hasan, Xiudong Guan, Gary Kohanbash, Dandan Sun
Journal: Neuro-Oncology (2018)

Glioblastoma is the most common and aggressive brain tumor with a median survival of ~15 months. Clinical trials of patients for immunotherapy showed an inferior response, which can in part attribute to an immunosuppressive, acidic tumor microenvironment (TME) composed of glioma-associated microglia/macrophages (TAMs), regulatory T-cells (Treg), and expression of immune checkpoint molecules. NHE1 maintains alkaline pHi in glioma and TAMs, promoting their migration and proliferation. Temozolomide (TMZ) therapy concurrently induces upregulation of NHE1 in glioma and alters TME immunogenicity. In this study, we investigated the impact of selective deletion of Nhe1 from microglia/macrophage using Cx3Cr1CreEr+/-;Nhe1f/f mice (Nhe1 KO). Non-immunogenic SB28-GFP glioma cells were transplanted intracranially, and tamoxifen (75 mg/kg, i.p.) was administered at 1–5 days post-glioma injection (d.p.i.). Cx3Cr1CreEr-/-;Nhe1f/f mice receiving identical treatment served as controls (Con). These mice were subsequently treated with DMSO or TMZ (2.5 mg/kg, i.p.) at 2–6 d.p.i. TAM infiltration and T-cell profile were analyzed by flow-cytometry at 10 d.p.i. TMZ monotherapy in Con mice elevated the tumor infiltrated microglia by 2-fold and macrophage numbers by 2.5-fold. In contrast, Nhe1 KO mice treated with TMZ did not exhibit a significant increase of microglia or macrophage infiltration. Ym-1+ tolerogenic macrophages in tumors from TMZ-treated Nhe1 KO mice were nearly abolished. TMZ treatment in Nhe1 KO mice also reduced the tumor-promoting CD4+CD25+FoxP3+ Treg infiltration but did not change CD8+GZMb+ and CD8+IFNγ+ populations. Moreover, combining TMZ with selective deletion of Nhe1 in Cx3Cr1+ cells significantly elevated CD4+PD-1+ and CD8+PD-1+ cell population. Most importantly, Nhe1 KO mice treated with combinatorial TMZ and anti-PD-1 therapy prolonged the animal survival. Taken together, our study suggests that NHE1 is involved in modulating TME and PD-1 expression. Blockade of NHE1 function in combination with TMZ and anti-PD-1 could improve TME and provide an alternative treatment strategy for glioblastoma. This was supported by NIH-grant R01NS75995(DS).
CBMT-31. QUIESCENT GLIOBLASTOMA CELLS SHIFT TO AN EPITHELIAL-MESENCHYMAL TRANSITION (EMT)-LIKE GENE PROGRAM
Authors: Rut Tejero, Yong Huang, Hongyan Zou, Roland Friedel
Journal: Neuro-Oncology (2018)

Glioblastoma (GBM) is the most common malignant primary brain tumor in adults, with a median survival rate of less than 15 months. Quiescent stem cells of GBM are potential sources for recurrence after therapy. Therapeutic targeting of this quiescent population in combination with therapies that target proliferative cells may be able to completely eradicate GBM tumors, however, our understanding of the physiology and molecular features of quiescent GBM cells is still limited. To isolate quiescent GBM stem cells and to investigate their molecular signature, we have engineered GBM cells with an inducible histone2B-GFP reporter (iH2B-GFP) by CRISPR/Cas9 knock-in. Quiescent GBM cells retain GFP-high label after pulse-chase paradigms. We utilized a 3D GBM organoid model that mimics tumor heterogeneity, including the formation of a quiescent population. GFP-high quiescent GBM cells were subjected to stem cell assays and RNA-Seq expression analysis. While quiescent GBM cells were similar in clonal culture assays to their proliferative counterparts, they displayed higher therapy resistance. RNA-Seq analysis of quiescent and proliferative GBM cells showed upregulation of EMT pathway genes and also induction of genes that modify the extracellular matrix. After exposure to irradiation or temozolomide, we observed increased fractions of the GFP-high population, demonstrating higher therapy resistance. Histological analyses of tumors growing in mouse host brains revealed the relative prevalence of quiescent cell populations near putative perivascular stem cell niches. Our findings connect quiescent GBM cells with an EMT-like shift, possibly explaining how GBM stem cells achieve high therapy resistance and invasiveness, and suggest new targets to abrogate the stem cell population of GBM. In addition, the upregulation of ECM components suggests that quiescent GBM cells may actively form their own extracellular “niche”, in line with the concept that a distinct microenvironment determines the physiology of GBM stem cells.
RBTT-04. DOES EXERCISE IMPROVE PROGRESSION FREE SURVIVAL AND QUALITY OF LIFE IN PATIENTS WITH GLIOBLASTOMA? A TRIAL IN PROGRESS
Authors: Kim Edelstein, Kristin Campbell, Lori Bernstein, Ilyse Lax, Felicity Backhouse, Gregory Pond, Navya Kalidindi, Rosemarylin Or, Normand Laperriere, Barbara-Ann Millar, David Shultz, Alejandro Berlin, Gelareh Zadeh, Catherine Maurice, Warren Mason
Journal: Neuro-Oncology (2018)

Glioblastoma is the most common adult malignant glioma, with poor prognosis and adverse neurological sequelae. Physical activity improves outcomes in patients with other cancers, but has not been evaluated in GBM. This prospective, single-arm intervention trial examines feasibility and preliminary efficacy of exercise on progression-free survival (PFS), cognition and quality of life (QOL) in newly diagnosed GBM patients. METHOD: Participants are English-speaking GBM patients scheduled for concurrent chemo-radiation at the Princess Margaret Cancer Centre, 18–65 years old, ECOG 2. The 3-month home-based exercise program, prescribed by a physiotherapist, includes aerobic and resistance training, tailored to prior fitness level, current physical status, and individual interests. Assessments of physical and neurocognitive functions, mood, fatigue, sleep, and QOL, occur within 2 weeks of starting chemo-radiation, and approximately 3, 6, 12, and 18 months later, or until tumor progression. Feasibility will be assessed by accrual, retention, and adherence rates. Outcomes include PFS (RANO criteria), change in cognition, physical activity and sleep (actigraphy, self-report questionnaires). Time-to-event outcomes will be estimated (Kaplan-Meier), and mixed modelling will explore individual and disease variables that contribute to outcomes. During the first seven months of recruitment, 51 newly diagnosed GBM patients scheduled to be treated at our institution were screened, 25 met eligibility criteria, and 16 consented. Four participants did not complete the exercise program; 3 withdrew consent, 1 refused concurrent chemoradiation. Two participants died after the intervention and one other progressed. No exercise-related serious adverse events occurred. Updated accrual and feasibility details will be presented at the meeting. DISCUSSION: Exercise appears feasible for GBM patients. Preliminary efficacy in terms of survival, performance status, cognition, sleep, mood, and QOL are under study. Results may guide physical activity recommendations in GBM, lay the groundwork for a larger randomized controlled trial, and generate avenues for translational research.
RARE-04. PDL1 LOSS OF EXPRESSION IN A METASTATIC CARCINOMA OF UNKNOWN PRIMARY WITH HEPATOID FEATURES TREATED WITH NIVOLUMAB
Authors: Katherine Wagner, Anna Levy, Zachary Levy, Mansoor Nasim, Michael Schulder
Journal: Neuro-Oncology (2018)

The anti-PD-1 monoclonal antibody nivolumab, used in metastatic melanoma, renal carcinoma, and advanced non-small cell lung cancer, may be used off-label in some PD-L1 positivite tumors. We report the first use (to our knowledge) of nivolumab in metastatic carcinoma of unknown primary with hepatoid features, with subsequent loss of PD-L1 expression on the tumor. CASE PRESENTATION: A 62-year old man complained of worsening back and right thigh pain. X-rays revealed an L3 compression fracture, which was managed non-operatively. He developed worsening right hip pain. Imaging revealed a right iliac mass, associated pathologic fracture, and multiple osteoblastic and osteolytic metastases. Iliac mass biopsy showed cords and nests of malignant epithelial cells with abundant eosinophilic cytoplasm, irregular nuclear contours, and prominent nucleoli. HepPar, Cam5.2, and PAX-8 (focal) immunohistochemical stains were positive, suggesting hepatic carcinoma. PD-L1 positivity was high (> 25% but < 50%). Genomic sequencing showed NF2, MLL2, and SETD2 mutations. Workup showed no hepatic involvement, so stage IV hepatoid carcinoma of unknown primary was diagnosed. TREATMENT: Several bony lesions were radiated. Nivolumab (240 mg every 2 weeks) and denosumab (monthly) were started. PROGRESSION: Seven months later he developed left ptosis and proptosis from a sellar/left cavernous sinus mass. Histology was similar to the previous iliac biopsy, but with more aggressive features (mitoses, atypical nuclei). Cam5.2 and synaptophysin immunohistochemical stains were positive; PD-L1 expression was <1%. Genomic sequencing showed PTEN, ERRFI1, CREBBP, EP300, LRP1B, MSH2, RB1 and P53 mutations, and increased mutational burden status (intermediate from low). DISCUSSION: PD-L1 expression may vary over time. Tumors can express PD-L1 constitutively or in response to IFNg from infiltrating lymphocytes. PD-L1 expression may decrease after IFNg levels decrease. Complete loss of PD-L1 has not, to our knowledge, been reported. CONCLUSION Loss of PD-L1 expression may represent a means by which tumors resist immunotherapy.
RTHP-18. POST-OPERATIVE RADIOTHERAPY FOR PATIENTS WITH FUNCTIONING AND NON-FUNCTIONING PITUITARY ADENOMAS: A SYSTEMATIC REVIEW AND META-ANALYSIS OF 7551 CASES
Authors: Nardin Samuel, Naif Alotaibi, Vinai Gondi, Osaama Khan
Journal: Neuro-Oncology (2018)

Although surgery is the mainstay of treatment for most pituitary adenomas, post-operative radiotherapy has been shown to be beneficial in improving tumour control and recurrence-free survival. However, due to the potential complications of with radiotherapy, the role of adjuvant radiotherapy in the setting of pituitary adenomas remains unclear. To address this gap, we performed a systematic review and meta-analysis to determine the efficacy and safety of post-operative radiotherapy in the treatment of pituitary adenomas. A systematic review was performed according to the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. We searched PubMed, MEDLINE and Cochrane databases with no language or publication date restrictions, and included studies where patients were treated post-operatively with any form of radiation therapy. Studies reporting on both functioning and non-functioning pituitary adenomas were included. Outcomes were reported as 5- and 10-year progression-free survival, as well as adverse events rates. Forest plots were generated to determine a pooled event rate and 95% confidence interval (CI) for each outcome using a random effect model analysis. A total of 86 studies from 1986–2017 met the inclusion criteria, with 7551 cumulative patients. Studies included patients with functioning adenomas only (n=12), non-functioning adenomas only (n=12) or both (n=20). The cumulative 5- and 10-year progression-free survival rates were 90.8% (95% CI 86–94%) and 88.6% (95% CI 81–93%), respectively. The overall adverse events rate was 8% (95% CI 5–12%). All outcomes were associated with significant heterogeneity (I2 70%). There were no differences in survival rates or adverse events in relation to study date, tumour pathology, radiosurgery system used or dose of radiation. CONCLUSIONS: Post-operative radiotherapy for pituitary adenomas is effective and safe. Because of the significant heterogeneity and lack of matched controls in the literature, optimum timing and dosage are still unclear. Further prospective studies are needed.
SGLT2 inhibitors for primary and secondary prevention of cardiovascular and renal outcomes in type 2 diabetes: a systematic review and meta-analysis of cardiovascular outcome trials
Authors: Thomas A Zelniker, Stephen D Wiviott, Itamar Raz, Kyungah Im, Erica L Goodrich, Marc P Bonaca, Ofri Mosenzon, Eri T Kato, Avivit Cahn, Remo H M Furtado, Deepak L Bhatt, Lawrence A Leiter, Darren K McGuire, John P H Wilding, Marc S Sabatine
Journal: The Lancet (2018)