bluuebunny/crossref_metadata_2025_split huggingface dataset:
CSIG-11. CENTRAL NERVOUS SYSTEM TUMOR PATIENTS HAVE ELEVATED LEVELS OF CIRCULATING EXTRACELLULAR VESICLES
Authors: Ricklefs Franz , Maire Cecile , Kolbe Katharina , Holz Mareike , Reimer Rudolph , Glatzel Markus , Chiocca Ennio , Westphal Manfred , Lamszus Katrin 
Published: November 2019

Abstract

BACKGROUND
We previously demonstrated that extracellular vesicles (EV) from CNS tumors reflect the molecular subtype of the original tumor and mediate an exchange of pro-oncogenic signals. EVs are commonly characterized by nanoparticle analysis (NTA), electron microscopy and tetraspanin markers, including CD9, CD81 and CD63. It is unclear, however, to what extent circulating tumor EVs are utilizable for diagnostic purposes and how their marker profile overlaps with EVs derived from other cell types. Aiming to define markers that allow distinction and enrichment of glioma EVs from patient blood, we utilized Imaging Flow Cytometry (IFC) to discriminate single EVs via multiple surface markers.

METHODS
EVs were isolated from blood of patients suffering from glioblastoma (n=24), anaplastic astrocytoma (n=8), brain metastasis (n=7), meningioma (n=12), pituitary gland tumor (n=11), epilepsy (n=11) and from healthy controls (n=18) and were analyzed by IFC, immunoblotting, electron microscopy and NTA. In addition, circulating EVs from PALM-GFP-GL261 and PALM-GFP-CT2A tumor-bearing mice (n=5) as well as from glioblastoma stem-like (GSC) cultures (n=4), neural stem cells (NSC), cerebral endothelial cells (cEC) and T-cells (n=4) were characterized.

RESULTS
CNS tumor patients have significantly elevated levels of circulating EVs (P < 0.001), as measured by NTA and IFC. In particular, the proportion of double positive CD9+/CD81+, CD9+/CD63+and CD63+/CD81+EVs is increased in glioblastoma patients (p=0.018) compared with healthy controls[L1]. In accordance, cultured GSCs secrete increased levels of CD9+/CD81+EVs in vitro. In the two syngeneic murine PALM-GFP glioma models, only 0.1-0.01% of circulating plasma EVs were found to be derived from intracranial tumors, underlining the need to identify markers that can enrich tumor-specific EVs for molecular profiling.

CONCLUSION
Glioma patients display increased levels of circulating plasma EVs that can be profiled by IFC, which is a unique and novel technique that facilitates discrimination of different EV subpopulations.
CSIG-16. RECONCILING TUMOR HETEROGENEITY IN GLIOBLASTOMA USING A PATHWAY-BASED APPROACH
Authors: Alvarado Alvaro , Kawaguchi Riki , Coppola Giovanni , Goldman Steven , Kornblum Harley 
Published: November 2019

Abstract
Despite efforts to gain a deeper understanding of its molecular architecture, glioblastoma (GBM) remains uniformly fatal. While genome-based molecular subtyping has revealed that GBMs may be parsed into several distinct molecular categories, this insight has yielded little progress towards extending patient survival. In particular, the great phenotypic heterogeneity of GBM – both inter and intratumorally – has hindered therapeutic efforts. To this end, we interrogated tumor samples using a pathway-based approach to resolve tumoral heterogeneity. Gene set enrichment analysis (GSEA) was applied to gene expression data and used to provide an overview of each sample that was then compared to others, generating sample clusters based on overall patterns of enrichment. The Cancer Genome Atlas (TCGA) samples were clustered using canonical and oncogenic signatures and in both cases the clustering was distinct from the molecular subtypes previously reported. Using principal component analysis (PCA) and other bioinformatics tools, we extracted gene sets to further characterize the pathways contributing to each of these clusters. We generated gene lists of the top common elements and Ingenuity pathway analysis exposed molecular targets that control critical pathways of each identified cluster. Similar analyses were completed in a gene expression database of patient-derived gliomasphere lines and molecular targets were also obtained. We found E2F1 to be a strong target based on gene lists from both databases. A cluster of gliomasphere lines have high enrichment scores for the gene list predicted to depend on E2F1. In vitro genetic perturbation showed decrease stem cell frequency and lower expression of cell cycle progression genes in cell lines from this cluster exclusively. Other cluster-specific targets are being validated and in vivo studies will follow momentarily. Our studies relate intertumoral heterogeneity to critical cellular pathways dysregulated in GBM, with the ultimate goal of establishing a pipeline for patient- and tumor-specific precision medicine.
CSIG-28. ROLE OF ALTERNATIVE SPLICING IN CONFERRING SPATIAL HETEROGENEITY SIGNATURES IN GBM
Authors: Ghosh Sadashib , Pavlyukov Marat S , Bastola Soniya , Li Chaoxi , Yamaguchi Shinobu , Komarova Svetlana , Yamashita Daisuke , Nakano Ichiro 
Published: November 2019

Abstract
Therapeutic interventions induce cell stress to trigger apoptosis in tumor cells. Specific cellular stressors, including those initiated by radio-chemotherapy, activate distinct pro-death proteins through a multitude of mechanisms. Apoptosis consists of highly regulated pathways involving post-translational modifications and cleavage of proteins leading to sequential inactivation of the main cellular processes e.g. cell cycle progression. Recently, we demonstrated that apoptotic bodies/ApoEVs in GBM transfer spliceosomal machinery components to neighboring cells, which are subsequently internalized and confer survival advantage through changes in mRNA splicing. Following the validation of the role of RBM11, a spliceosomal component in the said intercellular communication, we extended our findings in the characterization of spatially distinct clonally derived sphere lines from tumor edge and core-located tissues from GBM patients. We analyzed the expression of spliceosomal genes in edge and core-derived clones and found spatially distinct splicing capabilities and that the genes that were affected by alternative splicing events in edge and core cells have different splicing of genes that are involved in ubiquitination and regulate cell cycle progression. Downstream analyses revealed that the most promising target is MDM2. Importantly, this gene regulates cell cycle via ubiquitination. Further, western blot revealed differential expression of both RBM11 and MDM2 in egde and core-derived clones.Collectively, the data so far provides motivation for the possibility of finding cellular vulnerabilities in the splicing machinery and thus actionable targets for intervention that accounts for the bearings of spatial heterogeneity.
CMET-08. CEREBROSPINAL FLUID CARCINOEMBRYONIC ANTIGEN PREDICT PROGNOSIS IN LEPTOMENINGEAL METASTASIS FROM NON-SMALL CELL LUNG CANCER
Authors: Zhen Junjie , Li Shaoqun , Wen Lei , Lai Mingyao , Cai Linbo 
Published: November 2019

Abstract

BACKGROUND
Leptomeningeal metastasis (LM) is a detrimental complication of patients with non-small cell lung cancer (NSCLC) and its incidence has increased due to recent improvements in survival. The aim of this study was to identify the clinicopathological features and prognostic factors related to overall survival in NSCLC patients with LM.

METHODS
Seventy-four consecutive patients diagnosed with LM from NSCLC between 2009 and 2018 in Guangdong Sanjiu Brain Hospital were retrospectively reviewed.

RESULTS
Median KPS at diagnosis of LM were 60 (range, 20–90). Forty-seven (63.5%) patients harboring epidermal growth factor receptor (EGFR) or anaplasticlymphoma kinase (ALK) mutation while other twenty-seven patients (36.5%) were wild type or unknown status. Local treatment for LM consisted of whole-brain radiotherapy (WBRT) (52.7%), ventriculoperitoneal (VP) shunt (6.8%) and external drainage (6.8%). Systematic therapy for LM included EGFR or ALK tyrosine kinase inhibitors (TKI) (59.5%), chemotherapy (40.5%) and bevacizumab (8.1%). The median overall survival from diagnosis of LM to death was 8.1 months (95% confidence interval: 5.2 to 11.0). Patients with high Cerebrospinal Fluid (CSF) carcinoembryonic antigen (CEA) level (＞50ng/ml) had worse prognosis compared with those low CSF CEA level (≤50ng/ml) ones (p=0.02). However, there was no significant difference in survival between patients with high serum CEA and those with low serum CEA (p=0.645). EGFR/ALK mutation and EGFR/ALK TKI after LM were also identified as variables that had prognostic influence on survival, while KPS, concurrent brain metastasis, WBRT and chemotherapy had no prognostic value for survival.

CONCLUSION
Median overall survival was higher than historical experience in this retrospective analysis. It is CSF CEA level, but not serum CEA level that correlated with prognosis for LM from NSCLC.
CMET-09. A UNIQUE CASE OF PRIMARY GLIOSARCOMA WITH METASTASIS TO SACRUM ON BEVACIZUMAB
Authors: Hrachova Maya , Xiao-Tang Kong , Perez Rosenthal Mari 
Published: November 2019

Abstract

INTRODUCTION
Gliosarcoma is a rare variant of glioblastoma that accounts for approximately 0.48% of all adult brain tumors. Although, metastatic potential of gliosarcoma via hematogenous route has been proposed in the past, we report the first case of metastasis to the sacrum while undergoing treatment on bevacizumab. CASE REPORT: A 40-year-old woman presented with acute onset severe headache with pertinent examination findings of left upper extremity pronator drift. Imaging revealed right frontal lobe enhancing mass measuring 4.5 x 3.7 cm associated with edema and 10 mm leftward midline shift. A right frontal craniotomy for tumor debulking showed gliosarcoma (IDH wild-type, WHO grade 4). She was initiated on radiotherapy with concomitant and adjuvant temozolomide via Stupp’s protocol after second debulking surgery. Chemotherapy regimen was changed to bevacizumab when tumor progression was identified. Within six months of initiation of bevacizumab, she developed left leg shooting pain. Imaging revealed heterogeneously enhancing mass in the left hemisacral region measuring 6.2 cm concerning for metastatic process. Sacral bone biopsy showed malignant cells which were negative for an extensive immunohistochemical panel (including GFAP and Olig2), suggesting metastasis of the sarcomatous element of gliosarcoma and arguing against a second malignancy. Next generation sequencing performed on both the intracranial and sacral tumor showed an identical molecular prolife (including PTEN, NF1, TERT and TP53 genomic alterations), confirming common origin. After completion of radiation therapy to sacral region, chemotherapy regimen included lomustine followed by pembrolizumab. The patient died at 14 months after initial presentation due to disease progression.

DISCUSSION
To the best of our knowledge, this is the first case primary of gliosarcoma with metastases to the sacrum while evolved on chemotherapy with bevacizumab. The aim of this report is to bring awareness to medical community in order to expedite the diagnosis and management.
CMET-14. BRAIN METASTASES: A NEW PATHOPHYSIOLOGY, A NEW TREATMENT PARADIGM, AND, PERHAPS, A NEW PROGNOSIS
Authors: Dowd Richard , Ouyang Tao , Thamburaj Krishnamoorthy , Aregawi Dawit , Safran Howard , Zacharia Brad , Glantz Michael 
Published: November 2019

Abstract

INTRODUCTION
Brain metastases are widely held to reach the CNS through the blood stream. We provide evidence that the initial site of most CNS metastases is the CSF, with subsequent invasion of brain parenchyma. We also model the therapeutic implications of this novel hypothesis.

METHODS
Two neuro-radiologists independently assessed whether brain metastases were contiguous with CSF spaces in 200 consecutive patients using pre-treatment MRI. CSF was examined for malignant cells in 66 newly diagnosed, previously untreated patients. We contoured normal brain MRIs of 3 patients to calculate the percentage of brain within 5 mm of a CSF space. We queried an international neoplastic meningitis database to document response of brain metastases to intra-CSF chemotherapy.

RESULTS
Mean age was 64.2. One hundred patients were male; 143 had lung cancer, 15 melanoma, 12 gastrointestinal, 11 breast, 9 renal, 7 bladder. Mean number of metastases was 4.63. Eighty-five percent of metastases touched a CSF space. In 67% of patients, all metastases touched a CSF space. Neither histology, number or size of metastases, nor patient age predicted contiguity with CSF spaces. In our consecutive subset of patients, 44% (10/23) with one, 46% (5/11) with two, 63% (5/8) with three, and 71% (17/24) with >3 metastases had malignant cells in the CSF (R2=0.93, p=0.037). Five of 7 patients with both brain and CSF metastases receiving only IT chemotherapy experienced a substantial reduction in the size of at least some metastases. Up to 75% of the brain parenchyma lies within 5 mm of CSF spaces.

CONCLUSIONS
Our data suggest that brain metastases may access the CNS through the CSF rather than the bloodstream. IT chemotherapy may treat brain metastases. We suggest that the CSF should be monitored in all patients with, or at risk for, brain metastases. True cures may require treatment of the CSF space.
CMET-18. IMPACT OF KRAS MUTATION STATUS ON THE EFFICACY OF IMMUNOTHERAPY IN LUNG CANCER BRAIN METASTASES
Authors: Lauko Adam , Ali Assad , Sagar Soumya , Barnett Addison , Li Hong , Chao Samuel , Stevens Glen , Pennell Nathan , Peereboom David , Yu Jennifer , Murphy Erin , Angelov Lilyana , Funchain Pauline , Mohammadi Alireza , Suh John , Barnett Gene , Ahluwalia Manmeet 
Published: November 2019

Abstract

BACKGROUND
Immunotherapy is increasingly used in patients with non-small cell lung cancer brain metastases (NSCLCBM). KRAS mutations are associated with worse prognosis and there is no FDA approved targeted therapy. KRAS mutations are associated with increased expression of PD-L1. We evaluated the outcomes of NSCLCBM with KRAS mutations treated with immune checkpoint inhibitors (ICI).

METHODS
We reviewed 800 patients with NSCLCBM treated at our tertiary care center. 226 had known KRAS mutational status, 121 of which received immunotherapy. Overall survival (OS) was calculated from either the start of immunotherapy (when both groups received immunotherapy) or from the date of diagnosis of brain metastasis. Kaplan-Meier method and Cox Proportional hazard model were utilized to determine differences in OS and the Chi-square test was utilized to determine differences in PD-L1 expression.

RESULTS
In 109 patients where both KRAS and PD-L1 status were known, KRAS mutations had greater PD-L1 expression (80.1% vs 61.9% positive, p=0.04). There was no difference in OS between KRAS mutant vs KRAS wild-type patients treated with immunotherapy. Median survival from the start of immunotherapy was 15.6 vs 15.5 months respectively (p=0.7), after adjusting for age, KPS, lesion number and extra-cranial metastasis (HR = .91, p=.7). Patients with KRAS mutations treated with immunotherapy versus those who received chemotherapy had a 1-year OS from the diagnosis of brain metastasis of 60.9% vs 38.7% respectively (trending towards significance, p=0.05). KRAS wild-type patients treated with immunotherapy versus those who did not receive immunotherapy had a 1-year OS from the diagnosis of brain metastasis of 61.9% vs 62.5% (p=0.85), respectively.

DISCUSSION
KRAS mutations are associated with increased PD-L1 expression. Use of immunotherapy negates the poor outcomes seen traditionally in patients with NSCLCBM and KRAS mutations and it improves survival compared to use of chemotherapy. Our experience supports the use of immunotherapy in these patients.
CMET-30. COMPREHENSIVE METHYLOME ANALYSIS OF EGFR-MUTANT PRIMARY LUNG ADENOCARCINOMA AND MATCHED BRAIN METASTASIS
Authors: Mamatjan Yasin , Cabanero Michael , Zuccato Jeffrey , Weiss Jessica , Karimi Shirin , Sorotsky Hadas , Tsao Ming , Aldape Kenneth , Shepherd Frances , Zadeh Gelareh 
Published: November 2019

Abstract
Brain metastasis (BM) in patients with EGFR-mutant lung adenocarcinoma is a major determinant of overall survival. Novel insight into the genetic and epigenetic underpinnings of BM development is lacking. The aim of this study is to compare the methylome of EGFR-mutant primary lung adenocarcinoma (EGFRM-PLA) and matched BM to identify important alterations for the mechanisms of BM. Matched EGFRM-PLA and BM tumors from seven patients were profiled using the Illumina Infinium MethylationEPIC BeadChip array. Unsupervised clustering analyses of the 14 samples showed a similar whole DNA methylation signatures between EGFRM-PLA and BM tumors. Furthermore, PCA plot highlighted that seven matched BM and lung tumor samples were clustered together closely based on matching pairs for the most variable probes (2.5K to 10K). These observations indicate high level of concordance and the same cell of origin. However, these fourteen samples clustered into two groups based on tumor site being lung or brain based on 83K differentially methylated CpG sites. Of the 83K probes, 2.4K were either hypermethylated or hypomethylated in all lung samples. A quarter of these 2.4K probes were located in promoter regions. Specifically, we identified differences in methylation status of EGFR/ALK promoter regions in lung tumors versus BM. CNV analyses showed higher deep deletions of chromosomes and genes in BM compared to EGFRM-PLA. Leukocytes unmethylation for purity (LUMP) scores which indicate immune cell infiltration were similar between lung and BM pairs (Mean LUMP_score=0.64) consistent with high immune cell infiltration. Our results indicated a similar whole DNA methylation signature of EGFRM-PLA and matched BM, while comprehensive analysis identified important differentially methylated probes. Distinct differences in CNV alterations were observed in lung versus brain samples. The BM and EGFRM-PLA showed similar tumor purity and immune cell components. Overall, tumor methylation profiling provides clinically important information regarding biology of BM in EGFRM-PLA.
CMET-31. WHOLE BRAIN RADIOTHERAPY VERSUS STEREOTACTIC RADIOSURGERY IN POOR-PROGNOSIS PATIENTS WITH 1 – 10 BRAIN METASTASES: A RANDOMIZED FEASIBILITY STUDY
Authors: Nichol Alan , Raman Srinivas , Mou Benjamin , Hsu Fred , Valev Boris , Cheung Arthur , Vallières Isabelle , Beaton Laura , Rackley Thomas , Gondara Lovedeep 
Published: November 2019

Abstract

BACKGROUND
The clinical advantage of stereotactic radiosurgery (SRS) over whole brain radiotherapy (WBRT) in patients with brain metastases and poor prognosis is controversial. To investigate the feasibility of a phase III clinical trial in a population of patients with poor prognosis, we conducted a randomized feasibility study of WBRT versus SRS.

METHODS
Patients with Karnofsky performance status (KPS) ≥ 70, life expectancy of 3–6 months, based on both Diagnosis-Specific Graded Prognostic Assessments and attending oncologist opinion, and 1– 10 brain metastases with a diameter ≤ 4 cm were enrolled at six Canadian cancer centers. Patients were randomly assigned to WBRT (20 Gy in 5 fractions) or SRS (15 Gy in 1 fraction). The primary endpoint was the rate of accrual. A secondary endpoint was the ratio of screened subjects to accrued subjects. This trial is registered with ClinicalTrials.gov (NCT02220491).

RESULTS
Between January 2015 and November 2017, 210 were screened to enroll 22 patients (9.5 screened/participant) and 20 patients were randomized. The accrual rate was 0.63 patients / month. The most common reasons for exclusion were: estimated median survival outside 3–6 months (n = 40), baseline KPS below 70 (n = 28), and > 10 brain metastases (n = 28). The median survival was 7.0 months. The overall survival was 9.5 months (n = 11) for patients who had subsequent systemic therapy, compared to 3.7 months (n = 9) in patients who had none. In both arms, the cumulative incidence of retreatment with brain radiotherapy was 40%.

CONCLUSIONS
Accrual was slow and the median survival was longer than expected, but a randomized trial evaluating WBRT vs SRS in patients with poor prognosis would likely be feasible by enrolling only patients with no remaining systemic therapy options.
COMP-16. COMPREHENSIVE TRANSCRIPTOMIC ANALYSIS OF SINGLE CELLS FROM RECURRENT AND PRIMARY GLIOBLASTOMA TO PREDICT CELL-TYPE SPECIFIC THERAPEUTICS
Authors: Suter Robert , Stathias Vasileios , Jermakowicz Anna , Semonche Alexa , Ivan Michael , Komotar Ricardo , Schürer Stephan , Ayad Nagi 
Published: November 2019

Abstract
Glioblastoma (GBM) remains the most common adult brain tumor, with poor survival expectations, and no new therapeutic modalities approved in the last decade. Our laboratories have recently demonstrated that the integration of a transcriptional disease signature obtained from The Cancer Genome Atlas’ GBM dataset with transcriptional cell drug-response signatures in the LINCS L1000 dataset yields possible combinatorial therapeutics. Considering the extreme intra-tumor heterogeneity associated with the disease, we hypothesize that the utilization of single-cell RNA-sequencing (scRNA-seq) of patient tumors will further strengthen our predictive model by providing insight on the unique transcriptomes of the cellular niches present within these tumors, and into the transcriptional dynamics of these same cellular niches. By sequencing single-cell transcriptomes from recurrent GBM tumors resected from patients at the University of Miami, and integrating our datasets with previously published scRNA-seq data from primary GBM tumors, we are able to gain additional insight into the differences between these clinical distinctions. We have analyzed the differential expression of kinases both across and within distinct cell populations of primary and recurrent GBM tumors. This transcriptional map of kinase expression represents the heterogeneity of potential targets within individual tumors and between recurrent and primary GBM. Additionally, by generating disease signatures unique to each cellular population, and integrating these with transcriptional drug-response signatures from LINCS, we are able to predict compounds to target specific cell populations within GMB tumors. Additional computational techniques such as RNA velocity analysis and cell cycle scoring elucidate temporal insights to further prioritize these cell-type specific therapeutics, and reveal the intra-cellular dynamics present within these tumors. Collectively, our studies suggest that we have developed a novel omics pipeline based on the single cell RNA-sequencing of individual GBM cells that addresses intra-tumor heterogeneity, and may lead to novel therapeutic combinations for the treatment of this incurable disease.