bluuebunny/crossref_metadata_2025 huggingface dataset:
CTNI-59. FIRST SAFETY ANALYSIS OF ANAPLASTIC MENINGIOMA PATIENTS TREATED WITH TUMOR TREATING FIELDS (TTFIELDS)
Authors: Mawrin Christian
Published: December 2020

BACKGROUND

Anaplastic meningioma (AM) is a rare and aggressive intracranial tumor with very limited treatment options. TTFields is an established therapy and indicated for the treatment of newly diagnosed and recurrent glioblastoma (GBM) patients. The phase 3 study METIS tests the application in another intracranial cancer type, more specifically brain metastases of non-small cell lung cancer. First preclinical data show that TTFields can reduce proliferation of patient-derived meningioma cells and one first case report of a GBM patient with an in-field meningioma was published. First clinical trials are underway to investigate the safety and efficacy in meningioma patients (NCT02847559). Here, we describe first surveillance data on anaplastic meningioma patients treated with the TTFields device indicated for GBM treatment.

METHODS

Global post-market surveillance data of patients with anaplastic meningioma were assessed employing the MedDRA body system (System organ class (SOC) and preferred terms) with data cut-off in April 2020.

RESULTS

A total of 29 patients with AM were treated since 2015 to date. The median age is 57y (range 26-74y; based on YOB). Of those 9 (31%) were female and 20 (69%) were male. 15 (52 %) patients with AM reported at least one adverse event (AE). A total of 51 AEs were reported, of those 32 were assessed by the manufacturer as potentially related to TTFields treatment. Most commonly reported were skin reactions beneath the transducer arrays (n=15). No serious adverse events related to TTFields were reported.

CONCLUSION

Here we present the first post-market surveillance data of anaplastic meningioma patients treated with TTFields. Clinical studies are warranted to investigate the safety and efficacy for the use of TTFields in anaplastic meningioma patients.
DDRE-02. THERAPEUTIC TARGETING OF BRAIN METASTASIS WITH ERK INHIBITOR LY3214996 USING A NOVEL IN VIVO MODEL OF LUNG-TO-BRAIN METASTASIS
Authors: Singh Mohini , Nayyar Naema , Brastianos Priscilla
Published: December 2020

Brain metastases (BM) are the most common neoplasm to affect the adult central nervous system, occurring ten times more frequently than primary brain tumors. BM develop in 40–50% of advanced lung adenocarcinoma (LUAD), but the lack of durable response to chemotherapy, immunotherapy, or targeted therapy results in death within a year of BM diagnosis. Several advances have been made in identifying genetic drivers of primary cancers. For instance, the ERK pathway is critical in oncogenesis, with aberrations linked to driving the progression and metastasis of LUAD. Unfortunately, BM remain poorly understood due to both the difficulty of obtaining a sizable collection of metastatic tissue samples as well as a lack of clinically relevant models. Typical models of BM utilize inoculation routes that are invasive and cannot fully recapitulate the entirety of the metastatic cascade. Here we present a novel murine model of BM through an intrathoracic inoculation method that recapitulates the development of primary lung tumors and brain metastases as seen in patients. Using this method, we evaluated the efficacy of LY3214996, an ERK inhibitor, in targeting BM. Seven days post-inoculation of a patient-derived NSCLC-BM line, mice received LY3214996 P.O. daily for 21 days, and were monitored weekly for metastases with bioluminescent imaging. Upon endpoint lungs and brains were also removed and imaged. In vitro we demonstrated a reduction in cell growth and invasion across multiple cell lines of varying KRAS status (NSCLC and NSCLC-BM) treated with LY3214996. In vivo, we saw a reduction in both lung tumor weight as well as frequency of BM. Further research is necessary to elucidate the dosing and efficacy of LY3214996 in our models in different genetic contexts. Nonetheless, our technique presents a novel preclinical tool to interrogate the metastatic process, allowing validation of genetic drivers as well as therapeutic screening.
DDRE-16. SYNERGISTIC TUMOR SUPPRESSION FROM COMBINATION OF ONC201 AND EPIGENETIC MODULATORS EZH2 OR HDAC INHIBITOR PROVIDES A NOVEL TREATMENT STRATEGY FOR GBM AND DMG
Authors: Zhang Yiqun , Zhou Lanlan , Howard Safran , Seyhan Attila , El-Deiry Wafik
Published: December 2020

ONC201 is a promising anti-cancer agent that kills tumor cells by triggering an integrated stress response (ISR) dependent on ATF4. ONC201 demonstrated tumor regression and prolonged disease stability in patients with histone H3K27M-mutated midline glioma. The Enhancer of Zeste Homolog 2 (EZH2), a subunit of the polycomb repressive complex 2 (PRC2), is a histone methyltransferase that tri-methylates H3K27 (H3K27me3) and silences target genes. EZH2 inhibitors (EZH2i) reduce global H3K27 methylation. Based on the fact that the H3K27 mutation reduces H3K27 dimethylation (H3K27me2) and trimethylation (H3K27me3), we hypothesized that ONC201 sensitivity and tumor cell death may be enhanced by reducing H3K27 methylation with EZH2i as a mimic of H3K27M-mutation and by increasing H3K27 acetylation with histone deacetylase inhibitors (HDACi). We evaluated synergy of EZH2i EPZ-6438 or HDACi vorinostat with ONC201 against GBM cell lines, U251 and T98G-1 and DMG cell line, SF8638. Cell viability was determined with the Cell Titer Glo assay. Apoptosis was evaluated through immunoblotting of cleaved PARP and flow cytometry analysis of cell distribution. ISR activity was evaluated using immunoblotting of ATF4. Our result demonstrate that ONC201 synergistically reduced cell viability with vorinostat in U251, T98G-1 and SF8628 cell lines, induced apoptosis in combination with vorinostat in U251 and SF8628. ONC201 synergistically reduced cell viability and induced apoptosis with EPZ-6438 in U251. The immunoblotting detected no enhancement of ATF4 by addition of EPZ-6438 to ONC201. Immunoblotting analysis showed that EPZ-6438 reduced H3K27me3 in U251. Our results unravel potent synergy between ONC201 and EZH2i or HDACi in GBM and DMG cell lines, and provide further insights into the role of H3K27me3 in ONC201 drug sensitivity.
DDRE-19. SPIDER VENOMS AS SOURCES OF MOLECULES FOR NEW CANCER TREATMENTS: THE EFFECTS OF THE SNX-482 PEPTIDE ON MACROPHAGE MODULATION
Authors: de Lima Munhoz Jaqueline , Thome Rodolfo , Ishikawa Larissa , dos Santos Natalia Barreto , da Rocha-e-Silva Thomaz A A , Sutti Rafael , Verinaud Liana , Araujo João Luiz Vitorino , Rostami Abdolmohamad , Raposo Catarina
Published: December 2020

Malignant primary brain tumors remain among the most difficult cancers to treat. In malignant tissues, macrophages are accumulated in a high infiltration being known as tumor-associated macrophages (TAMs). These cells are associated with poor prognostics in many types of cancer. Studies in our group demonstrated that the venom of Phoneutria nigriventer (PnV), a wandering spider from South America, has reduced the development of glioblastoma (GBM) in a murine model, inducing a large infiltrate of TAMs. Subsequently, in vitro results demonstrated that PnV activates macrophages, increasing the ability to kill tumor cells. The aim of this study was to analyze the effects of the peptide SNX-482 presented in the venom of Hysterocrates gigas in macrophages for further correlation with the PnV. Macrophages were differentiated from bone marrow precursors collected from male C57BL6 mice and differentiated for 7 days with M-CSF. These cells were used for polarization and coculture with T cells and analyzed by flow cytometry. PCR Array was also performed (QIAGEN) for the analysis of gene expression. The results showed that SNX-482 could activate macrophages in a not dose-dependent response. There was an increase in the main activation markers (CD40, CD80, CD86, CD68, CD83, and MHCII). The polarization indicated that the peptide potentiated the proinflammatory effect of M1 macrophages (increased MHCII and iNOS). The screening of 86 cancer-related genes showed that the Ccr4, Pdcd1, Gzmb, and IFN-γ genes had an increase in their expression. Furthermore, we developed in C57BL/6 mouse a pre-clinical model of intracranial glioblastoma using the Gl261 cell line. The results showed an applied-easy-safe model that could alter the gene expression of cancer markers. Taken together, all the results contributed to increasing the knowledge about the peptide SNX-482 and the model for further pre-clinical assays of glioblastoma, making a great advance in the development of new treatments.
DDRE-21. PNOC015: PHASE 1 STUDY OF MTX110 DELIVERED BY CONVECTION ENHANCED DELIVERY (CED) IN CHILDREN WITH NEWLY DIAGNOSED DIFFUSE INTRINSIC PONTINE GLIOMA (DIPG) PREVIOUSLY TREATED WITH RADIATION THERAPY
Authors: Mueller Sabine , Kline Cassie , Villanueva-Meyer Javier , Hoffman Carly , Raber Shannon , Bonner Erin R , Nazarian Javad , Lundy Shannon , Molinaro Annette , Prados Michael , Filbin Mariella , Gupta Nalin
Published: December 2020

OBJECTIVE

To determine safety and distribution of MTX110 delivered by CED in newly diagnosed DIPG patients.

METHODS

DIPG patients (3–21 years) were enrolled after radiation. CED of MTX110 combined with gadoteridol was completed based on dose levels (DL) (30–90 µM with volumes ranging from 3 cc (single dose) to 2 consecutive doses of 6 cc; total number of DL=7). Catheter position was chosen to maximize tumor coverage. Distribution of infusate was monitored with real-time MR imaging. Repeat CED was performed every 4–8 weeks if tolerated. Quality of life (QOL) assessments using PedsQL Generic Core and Brain Tumor modules were obtained at baseline (n=5), 3-months (n=3), and end of therapy (n=2). Single-cell RNA sequencing and analysis of histone modifications was performed to assess pharmacodynamic effects on DIPG cells.

RESULTS

Between May 2018-Dec 2019, 6 patients were enrolled (median age 8 years, range 5–21). Dose limiting toxicities included: grade 3 gait disturbance (DL7; cycle 1); grade 3 muscle weakness/vagus nerve disorder (DL5; cycle 4) and grade 2 intolerable dysphagia (DL7; cycle 4). Twelve CED procedures were completed at DL7 and repeated cycles ranged from 2 to 7. Infusion to distribution volume ratio was approximately 1:3.5. There were no significant changes in self-reported QOL. Parent ratings of patients’ worry (p = 0.04) and overall QOL (p = 0.03) significantly decreased at 3-months.

CONCLUSION

Repeat CED of MTX110 at the highest dose is tolerable. Tissue concentrations are likely to be substantially higher compared to oral dosing. Pharmacodynamic effects will be presented.
DDRE-25. NOVEL TEMOZOLOMIDE ANALOGS TO IMPROVE ANTI-TUMOR EFFICACY AND OVERCOME RESISTANCE IN GLIOBLASTOMA MULTIFORME
Authors: Waters Ariana , Tomimatsu Nozomi , Babic Ivan , Nurmemmedov Elmar , Allnutt Annamarie , Quan Yueqin , Nomura Natsuko , Burma Sandeep , Kesari Santosh , Yenugonda Venkata
Published: December 2020

Glioblastoma (GBM) is considered one of the most lethal forms of human cancers, and despite considerable advances in multimodality treatments, it remains an incurable disease with an overall survival of 14 to 16 months after diagnosis. Even in the era of personalized medicine and immunotherapy, temozolomide (TMZ), an oral alkylating agent, remains the standard-of-care for GBM. However, intrinisic or acquired resistance to TMZ due to over expression of O6-methylguanine-DNA methyltransferase (MGMT) results in initial treatment inefficacy or tumor relapse, highlighting the significant need for improved treatment strategies. Recently, much effort has been directed towards creating novel TMZ analogs to address the clinical barriers associated with TMZ. While some reported TMZ analogs showed improved brain permeability and anticancer effects in preclinical models, none of them have progressed to testing in humans. There is therefore significant room to improve the brain permeability and anticancer effect profiles of TMZ by incorporating yet unexplored functional groups into new analogs. We have designed and synthesized a series of novel C8-substituted TMZ analogs and have evaluated their anticancer potency against a panel of GBM cell lines with variable levels of MGMT expression. Encouragingly, our analogs demonstrated promising anti-cancer effect in both MGMT low and high expressing lines. We then evaluated our analogs in a variety of cell based assays to compare their activity with TMZ, and performed in vivo brain permeability and anti-tumor efficacy assays in mouse flank models. Our results demonstrated that several of our analogs clearly display improved anti-cancer effects and increased brain permeability over TMZ. This work points to a new direction for the development of novel TMZ analogs for improved patient survival.
DDRE-32. ABC TRANSPORTERS RESTRICT THE BRAIN PENETRATION AND INTRACRANIAL EFFICACY OF ANTICANCER AGENTS EVEN WHEN BLOOD-BRAIN BARRIER INTEGRITY IS LOST
Authors: de Gooijer Mark C , Kemper E Marleen , Buil Levi C M , Çitirikkaya Ceren H , Buckle Tessa , Beijnen Jos H , van Tellingen Olaf
Published: December 2020

The impact of the blood-brain barrier (BBB) in brain tumors on the efficacy of anticancer drug therapy is controversial. In primary as well as metastatic brain tumors, the BBB is often disrupted. Yet, many intracranial cancers respond poorly to systemic therapies. We characterized the integrity of the BBB in a series of experimental intracranial tumor models using magnetic resonance imaging (MRI), fluorescent dyes and autoradiography. We also assessed the distribution and efficacy of docetaxel in healthy brain tissue and brain tumors that were grafted into P-glycoprotein (P-gp) proficient wild-type (WT) and deficient Abcb1a/b-/- recipient nude mice. Leakiness of the tumor vasculature varied from extensive to almost absent. Tumor blood vessels expressed P-gp and breast cancer resistance protein (BCRP). The leakiness of the vasculature resulted in higher docetaxel levels in tumors compared to normal brain. However, P-gp expression in tumor vessels reduced the drug distribution in tumors, which also translated into a reduced efficacy. Taken together, these studies demonstrate that leakiness of the BBB does not necessarily imply good accessibility to brain tumors of drugs that are substrates of P-gp and/or BCRP. Although therapeutic responses may be observed, the full potential of such therapeutics can still be attenuated by drug efflux pumps in the tumor vasculature. Therefore, only BBB-penetrable drugs with low to no affinity for efflux transporters should be considered for treatment of intracranial tumors.
EPCO-04. GENOMIC AND EPIGENOMIC HALLMARKS OF SCHWANNOMATOSIS SCHWANNOMAS
Authors: Mansouri Sheila , Suppiah Suganth , Mamatjan Yasin , Paganini Irene , Liu Jeff , Karimi Shirin , Patil Vikas , Nassiri Farshad , Singh Olivia , Sundaravadanam Yogi , Rath Prisni , Sestini Robert , Gensini Francesca , Agnihotri Sameer , Blakeley Jaishri , Ostrow Kimberly , Largaespada David , Plotkin Scott , Stemmer-Rachamimov Anat , Ferrer Marcela Maria , Pugh Trevor , Aldape Kenneth , Papi Laura , Zadeh Gelareh
Published: December 2020

Schwannomatosis (SWNTS) is a genetic cancer predisposition syndrome that manifests as multiple and often, painful neuronal tumors called schwannomas (SWNs). Very little is known about the epigenomic and genomic alterations in SWNTS related SWNs (SWNTS-SWNs) other than germline mutations in SMARCB1 and LZTR1 plus somatic mutations in NF2 and loss of heterozygosity in chromosome 22q. Herein, we have comprehensively established the specific molecular signatures of SWNTS-SWNs. We found that tumor anatomic location was associated with pain and distinct DNA methylation and transcriptional signatures. DNA sequencing revealed several novel non-22q deletions, specifically in LZTR1-mutant cases. Whole-genome sequencing identified novel recurrent structural rearrangements. Further, chromosomal aberrations in SWNTS-SWNs were accompanied by increased transcription of mismatch repair genes. Our transcriptome analysis detected the SH3PXD2A-HTRA1 gene fusion in SWNTS-SWNs, more commonly in LZTR1-mutant tumors. In addition, we identified the specific genetic, epigenetic, and transcriptional hallmarks of painful SWNs that may be harnessed to develop new treatments for this debilitating syndrome.
EPCO-08. TUMOR-IMMUNE INTERACTIONS ARE DYNAMIC AND INFLUENCE THE EVOLUTIONARY TRAJECTORY OF ADULT DIFFUSE GLIOMA
Authors: Varn Frederick , Johnson Kevin , Barthel Floris , Kim Hoon , Wade Taylor , Lodha Disha , Ajaib Shoaib , Ahmed Nazia , Garofano Luciano , D’Angelo Fulvio , Stead Lucy , Noushmehr Houtan , Iavarone Antonio , Verhaak Roel ,   The GLASS Consortium
Published: December 2020

Diffuse glioma is an aggressive brain cancer that is characterized by a poor prognosis and a universal resistance to therapy. The evolutionary processes behind this resistance remain unclear. Previous studies by the Glioma Longitudinal Analysis (GLASS) Consortium have indicated that therapy-induced selective pressures shape the genetic evolution of glioma in a stochastic manner. However, single cell studies have revealed that malignant glioma cells are highly plastic, and capable of changing their cell state in response to diverse challenges in their microenvironment. The tumor immune response has been implicated as a major driver of these malignant cell state transitions, and is known to be affected by the administration of therapy, but the extent to which tumor genetics, therapy, and the different components of the immune response interact to influence a glioma’s evolutionary trajectory are poorly understood. To further investigate these factors, we collected DNA and RNA sequencing data on pre- and post-treatment tumor pairs from over 150 glioma patients that have received chemotherapy, radiotherapy, and/or immune checkpoint blockade agents. By integrating mutation, copy number, and in silico deconvolution analyses of bulk transcriptome data across the three molecular subtypes of diffuse glioma, we show that longitudinal increases in chromosomal instability and gene fusions associate with decreased immune infiltrate and altered cell states at recurrence. We additionally find that specific molecular alterations and malignant cell states associate with unique inflammatory and immunosuppressive programs in tumor-associated macrophages and microglia. Lastly, we show that the abundance of T cells in the tumor microenvironment does not associate with changes in neoantigen depletion and the acquisition of antigen presentation machinery defects, suggesting minimal immunoediting activity over time. Collectively, our results indicate that the administration of therapy can alter the dynamics of tumor-immune interactions in glioma, resulting in new steady-states at recurrence that can be subsequently targeted.
EPCO-28. SPHEROID STUDY OF A GLIOBLASTOMA TUMOR IDENTIFIED A SUBCLONAL MUTATION OF EGFR T790M
Authors: Rosenberg Shai , Steinberg Eliana , Yaacov Adar , Lutati Ranel , Mordechai Anat , Linetsky Eduard , Lossos Alexander , Paldor ido , Benny Ofra
Published: December 2020

BACKGROUND

Glioblastoma (GBM) is the most common and the most devastating primary brain cancer in adults. Precision genetic medicine approach does not provide benefit to majority of GBM patients. A major reason for this is tumor heterogeneity harboring potential resistance mechanisms. Here, we describe an approach to grow spheroids of GBM, containing tumor, stroma and vascular tissues. We show that this approach can identify undetected subclonal driver mutations that can potentially cause drug resistance later in the disease course.

METHODS

We grew spheroids of a GBM patient in a multi-well array and monitored them visually. Exome sequencing of the parental tumor (coverage of 557X) and of spheroids after 10 days (n=3) and 20 days (n=5) of growth was performed. In addition, we sequenced six spheroids that were grown for 10 days and treated by Temozolomide for the next 10 days.

RESULTS

70 somatic mutations were detected in the parental tumor. 42/70 of the tumor’s somatic mutations were also detected in the spheroids. 192 somatic mutations were detected in the spheroids only and not in the parental tumor despite high coverage sequencing of the parental tumor. In cancer genes: six somatic mutations were identified in the parental tumor, 5/6 were also detected in the spheroids and 13 mutations were detected only in the spheroids. EGFR V774M mutation was detected in both tumor and spheroids. However – EGFR T790M was independently detected in 7/11 of the spheroids sequenced after 20 days or growth but not in the parental tumor.

CONCLUSION

Analysis of GBM spheroids enables detection of rare subclonal mutations not detected in parental tumor. We hypothesize that this is due to positive selection of the ex vivo growth conditions. This analysis enabled detection of EGFR T790M – an important targetable resistance mutation in lung cancer not previously described in primary GBM.
EPCO-36. GENOMIC INSTABILITY AND TRANSCRIPTOMIC SIGNATURES UNDERLYING EPIGENETIC MENINGIOMA SUBGROUPS REVEALS MECHANISMS OF IMMUNE INFILTRATION AND THERAPEUTIC VULNERABILITIES
Authors: Choudhury Abrar , Magill Stephen , Prager Briana , Eaton Charlotte , Lam Tai-Chung , Pu Jenny Kan-Suen , Li Lai Fung , Leung Gerald , Vasudevan Harish N , Lucas Calixto-Hope G , Chan Jason W , Wendt Jake , Guerra Geno , Susko Matthew S , Braunstein Steve , Villanueva-Meyer Javier , Bush Nancy Ann Oberheim , Sneed Penny K , Berger Mitchel , Perry Arie , Solomon David , McDermott Michael W , Costello Joseph , Francis Stephen , Rich Jeremy , Raleigh David
Published: December 2020

BACKGROUND

Meningioma treatments are limited due to incomplete understanding of meningioma biology. To address this, we performed multiplatform molecular profiling on 565 meningiomas with comprehensive clinical data to define genomic drivers and identify therapeutic vulnerabilities.

METHODS

DNA methylation profiling was performed on meningiomas from UCSF (n=200, discovery) and Hong Kong University (n=365, validation). Median follow-up was 5.6 years, and there were 388/142/35 WHO grade I/II/III meningiomas. Copy number variants (CNVs) were calculated for all meningiomas, and RNA sequencing was performed on UCSF meningiomas. Cell type deconvolution, metagenomics, CRISPR, and pharmacology were used for mechanistic and functional validation.

RESULTS

Unsupervised hierarchical clustering of differentially methylated DNA probes revealed that meningiomas were comprised of 3 epigenetic subgroups associated with good, intermediate, and poor outcomes, with representation from all WHO grades in each subgroup. Meningiomas from the subgroup with the best outcomes (52% WHO grade I) were distinguished by recurrent gain of Chr5. Meningiomas from the subgroup with intermediate outcomes (31% WHO grade II) were distinguished by genomic stability, enrichment of innate immune genes, and immune infiltration in the setting of endogenous retroviral gene re-expression, a mechanism of immune recruitment. The most aggressive subgroup of meningiomas (57% WHO grade III) was distinguished by genomic instability, including recurrent loss of Chr22q harboring NF2, and decreased immune infiltration. Consistently, NF2 suppression in primary meningioma cells derived from immunogenic meningiomas decreased expression of innate immune genes critical for immune recruitment, suggesting a novel immunostimulatory function of NF2. The most aggressive subgroup of meningiomas were further distinguished by activation of the mitogenic FOXM1 transcriptional program, and recurrent loss of Chr9p harboring CDKN2A/B, which rendered primary meningioma cells from this subgroup susceptible to CDK4/6 inhibitors.

CONCLUSIONS

Meningiomas are comprised of 3 epigenetic subgroups defined by genetic mechanisms driving immune infiltration in the tumor microenvironment and meningioma cell proliferation.
EPCO-37. USING SINGLE-CELL RNA SEQUENCING TO IDENTIFY CELLULAR HETEROGENEITY WITHIN NON-FUNCTIONING PITUITARY ADENOMAS
Authors: Jain Saket , Babikir Husam , Shamardani Karin , CatalanSaavedra Francisca , Diaz Aaron , Aghi Manish
Published: December 2020

Pituitary adenomas (PA) are one of the most common primary brain tumors and comprise approximately 15% of brain neoplasms. Most PA are histologically benign but can cause significant morbidity. Previous studies utilized whole-genome and exome sequencing to identify a few somatic variants, but no recurrent mutations were observed. Further studies are warranted to identify driver mutations occurring at low frequencies. We used single-cell RNA sequencing (10X Genomics) to investigate cellular heterogeneity in three non-functioning pituitary adenomas. Our analysis identified discrete clusters of cells associated with specific functional pathways. One of these clusters corresponded to cells expressing genes related to metabolic pathways, primarily lipid metabolism. Another cluster consistent amongst the three patients comprised of cells involved in antigen presentation and processing. In addition, the copy number variation analysis highlighted distinct chromosomal alterations within our samples. Interestingly, we were able to identify clonal variations within each tumor based on chromosomal aberrations. For example, in our first patient, we observed a gain of chromosome 19 and loss of chromosome 2. Our analysis showed three different clonal populations within this tumor. All three populations harbored the loss of chromosome 2, one population exhibited gain of chromosome 19, while a third population exhibited loss of chromosome 19. These early results indicate the loss of chromosome 2 as an early event in tumorigenesis and gain/loss of chromosome 19 as late events. We are currently in a process of identifying somatic variations within these tumors by variant calling. Currently we are expanding our analysis to 20 non-functional PA. Mapping the single-cell gene expression profiles with mutational phylogeny will reveal the differences in clonal evolution within the tumor subtypes. This study will help us define the molecular fingerprint of pituitary adenomas and provide insights which could be utilized in the clinic for better management of these tumors.
EPID-04. THE SINGLE CENTER STUDY FOR BRAIN METASTASES OF UNDIAGNOSED PRIMARY TUMOR AND THE ROLE OF SURGICAL REMOVAL
Authors: Shimizu Yuzaburo , Suzuki Mario , Akiyama Osamu , Kondo Akihide
Published: December 2020

BACKGROUND

The diagnosis of a brain metastases is generally made during the follow up examinations of patients with primary known cancer. However, there are some patients presenting brain metastases as the first manifestation of a previously undiagnosed primary tumor (UDP) pathological confirmation of the diagnosis. The timing of a subsequent neurosurgical intervention is influenced by the distribution of primary tumors in UDP patients. The purpose of this study was to investigate the optimal diagnostic approach and the role of surgery for UDP patients.

METHODS

In a retrospective study, 35 patients admitted to our institution and underwent brain tumor removal from 2017 to 2019 with the diagnosis of cerebral metastases and diagnosed lung cancer as primary tumor subsequently, or previously diagnosed lung cancer.

RESULTS

UDP patients represented 46% of the whole group. Primary tumor subtype was the adenocarcinoma (n=13, 81%), small cell carcinoma (n=2, 13%), and neuroendocrine carcinoma (n=1, 6%). They did not have bronchoscopy nor excision of lung cancer. On the other hand, the patients previously diagnosed lung cancer represented 54% and subtype was adenocarcinoma (n=14, 74%) and small cell carcinoma (n=5, 26%). EGFR mutation was detected from 7 patients (44%) in UDP group and treated by EGFR tyrosine kinase inhibitor.

CONCLUSION

The significance of surgical intervention in metastatic brain tumors has been limited. However, active surgical intervention in UDP patients could identify not only histological diagnosis but also molecular biological characteristics. Our study suggests the possibility to avoid whole brain radiation in UDP patient by the active surgery.
EPID-20. NOVEL GLIOBLASTOMA POPULATION-BASED HISTOLOGIC STAIN NORMALIZATION
Authors: Agraz Jose , Grenko Caleb , Viaene Angela , MacLean Nasrallah , Feldman Michael , Akbari Hamed , Bakas Spyridon
Published: December 2020

Histopathologic evaluation has been an integral part of clinical diagnosis for central nervous system tumors, providing information essential for classification, management, and treatment of the disease. Hematoxylin and eosin (H&E) staining is routinely used in histology, providing detail of tissue morphology, structure, and cellular composition. MOTIVATION: Slide staining is rife with color intensity variations, mainly due to differences in materials and staining protocols among others. These variations introduce inaccuracies in downstream computational analysis and quantification of disease, disabling the generalization of computational models. To overcome these variations, current approaches arbitrarily select a slide within the cohort to normalize all slides of the cohort, leading to non-reproducible results in other cohorts. We develop a population-based whole slide image (WSI) normalization method based on overall region driven stain vectors and color histogram, weighted by corresponding percent contribution to overall slide (PCOS). METHODS: We identified a cohort of 509 H&E stained WSIs with corresponding anatomical annotations from the Ivy Glioblastoma Atlas Project. These WSIs and annotations were reviewed by two neuropathologists for correctly annotated regions. Each region was weighted according to PCOS, WSIs with PCOS < 0.05% were discarded. Then, the optical densities and histograms calculated. Resulting color histogram and optical density was applied to the WSI cohort. Finally, stain intensity variability pre- and post- normalization was compared. RESULTS: Normalizing WSIs based on our approach, results in a significant (p < 0.01, Wilcoxon) improvement in color intensity variation for eight of nine regions tested, with the exception of “Pseudopalisading Cells with no visible Necrosis” (p = 0.8). DISCUSSION: This novel transformative technique is insensitive to artificially staining background density and straightforward to apply. Furthermore, the approach shows promise towards a viable and robust tool for stain normalization in large WSIs cohorts, with the potential towards a stain normalization standard generalizable to other diseases.
EPID-21. EPIDEMIOLOGY OF MALIGNANT GLIOMAS IN KOREA USING NATIONWIDE BIG DATA FROM 2007 TO 2017
Authors: Ho Yang Seung
Published: December 2020

The purpose of the study of the study is to investigate the incidence, prevalence, and survival of malignant glioma (MG) using population-based Korean National Health Insurance Database (NHID) data. We identified patients with MG as C71 codes in KCD 5–7 according to ICD-10 from 2007 to 2017. Epidemiological characteristics of MG, including annual incidence, prevalence, mortality rates, and survival rates, were collected and analyzed according to socioeconomic state (SES) and treatment modalities. 45,066 new patients with MG were identified from 2007 to 2017. An age-adjusted incidence of 7.47 per 100,000 people. The mean age at diagnosis was 54 years. The male to female ratio was 1.11. Mortality and survival probability were analyzed among total subjects and in subgroups. The mortality of female patients was lower than that of male patients (hazard ration, 0.69; 95% CI, 0.67–0.71), and younger age and higher income had significantly lower mortality rate. The 1-, 3-, 5-, and 10-year total relative survival rates were estimated at 63.4%, 46.2%, 39.4%, and 34.8%, respectively. This is the first population-based study to determine the incidence and prevalence of MG according to epidemiological characteristics in Korea using NHID data. Our study found that female sex and high SES were factors that significantly lowered the mortality rate in MG, and younger groups and operated patients showed significantly higher survival rates.
EPID-24. OBESITY IN MALES WITH MENINGIOMA: A U.S. POPULATION-BASED STUDY
Authors: Shahin Maryam , Rae Ali , Ramos Christian Lopez , Bagley Jacob , Bowden Stephen , Bullis Carli , Cetas Justin , Han Seunggu
Published: December 2020

BACKGROUND

The female predominance of meningiomas may reflect a hormonal influence on tumorigenesis. Obesity alters steroid synthesis and chronically exposes men to hyperestrogenemia.

OBJECTIVE

Identify differences in males undergoing craniotomy for meningioma compared to other tumors or aneurysms.

METHODS

The National Surgical Quality Improvement Program was retrospectively queried from 2013–2018 for cases of craniotomy for resection of meningioma, other tumor, and aneurysm by CPT code in male patients and confirmed with postoperative ICD-10 code. Height and weight data were used to create body mass index (BMI): underweight (< 18.5), normal (18.5 to< 25), overweight (25 to< 30), class I obesity (30 to< 35), class II obesity (35 to< 40), and class III obesity (40+).

RESULTS

We identified 2,458 males who underwent craniotomy for meningioma, 9,889 for other tumor, and 386 for aneurysm. Using multivariable logistic regression, age (OR 1.01 per year, 95% CI 1.01-1.01, p< 0.001), diabetes mellitus (OR 1.32, 95% CI 1.17–1.48, p< 0.001), and increasing BMI (overweight: OR 1.55, 95% CI 1.36–1.76, p< 0.001; class I: OR 2.00, 95% CI 1.75–2.30, p< 0.0001; class II: OR 2.05, 95% CI 1.24–1.76, p< 0.001; class III: OR 1.47, 95% CI 1.24–1.76, p< 0.0001) were significantly and independently associated with craniotomy for meningioma compared to other tumor or aneurysm. For other tumor, higher BMI was associated with lower likelihood (overweight: OR 0.70, 95% CI 0.62–0.79, p< 0.001; class I: OR 0.55, 95% CI 0.49–0.63, p< 0.001; class II: OR 0.52, 95% CI 0.44–0.62, p< 0.001; class III: OR 0.74, 95% CI 0.63–0.87, p< 0.001). For aneurysm, there was no significant difference (overweight p=0.70; class I p=0.65; class II p=0.76; class III p=0.57).

CONCLUSIONS

BMI independently predicts having craniotomy for meningioma when compared to other tumor or aneurysm amongst US male patients.
EPID-26. CLINICAL AND HISTOLOGICAL CHARACTERIZATION OF PRIMARY CENTRAL NERVOUS SYSTEM SARCOMA IN PEDIATRICS. A SINGLE INSTITUTION EXPERIENCE IN A MIDDLE-INCOME COUNTRY
Authors: Cabrera Edgar , Aponte Nelson , Garcia Johnny , Salazar Fredy , Bouffet Eric , Bartels Ute , Jaramillo Lina , Fonseca Adriana
Published: December 2020

INTRODUCTION

Primary central nervous system (CNS) sarcomas are rare mesenchymal non-meningothelial tumors accounting for less than 0.2% of intracranial lesions. Diagnosis and management are challenging due to the current lack of substantive clinical, histological and molecular data.

METHODS

We retrospectively identified all patients with diagnosis of primary CNS sarcoma at the Hospital Fundación Pediatrico la Misericordia (HOMI) in Bogota, Colombia. We collected patient demographics, disease characteristics, and outcomes for analysis.

RESULTS

Between 2008 and 2020, twenty-four consecutive patients were diagnosed at the HOMI representing 6% of all CNS tumors diagnosed over the same time period. The median age at presentation was 9.48 years (range:1.6–13.4). The median time of symptoms prior to diagnosis was 2 weeks (0.1–24). The most common presentation was headache (21/24- 89%) and vomiting (19/24- 79%). The frontal lobe was involved in 63% of patients (15/24) and only one patient presented with a cerebellar lesion. Histologically, these tumors were characterized by a pleomorphic spindle cell architecture and high mitotic activity. All samples lacked immunoreactivity to GFAP, CD34, EMA, and S100 and all samples had strong nuclear immunopositivity for TLE-1; BCL-2 was reactive in eighteen cases. Gross total resection was attained in fifteen patients, most patients received focal radiation therapy and ICE chemotherapy. Progression-free survival at 12 and 24 months was 57% and 31% respectively. Overall survival was 77% at 12 months and 39% at 24 months. Thirteen patients relapsed, 11 presented with local failures, and 2 with intracranial recurrences outside of the radiation field.

CONCLUSION

Our study identifies TLE-1 as a diagnostic marker of primary CNS sarcoma, a highly malignant supratentorial tumor of childhood. Further molecular studies are urgently needed to elucidate the biology of this disease and the unusually high incidence observed in the Colombian pediatric population.
EPID-27. THE VANISHING TUMOR PHENOMENON IN THE DIAGNOSIS OF PRIMARY CNS LYMPHOMA
Authors: Yim Eunji , Umemura Yoshie , Sun Yilun , Junck Larry
Published: December 2020

INTRODUCTION

Steroid is commonly initiated for newly recognized brain tumors. For primary CNS lymphoma (PCNSL), however, its lympholytic effect can partially treat the tumor and obfuscate the surgical-pathological diagnosis needed to initiate chemotherapy. Evidence for this remains controversial. In this study we investigated the incidence of the vanishing tumor phenomenon and its association with steroid use.

METHODS

Patients > age 18 with PCNSL were identified from January 1, 2000 to April 30, 2020 within the University of Michigan Health System. Clinic and operative notes, pathology, imaging, and lumbar puncture results were reviewed. Inclusion required histopathologic diagnosis from brain tissue, cerebrospinal fluid, or autopsy, including diagnosis on repeat biopsy. Patients with prior/concurrent systemic lymphoma, HIV, organ transplant, or diagnosis established from primary ocular disease were excluded. Date(s) of biopsy, steroid initiation, and recurrence (by imaging) were abstracted. We defined vanishing tumor as a lesion whose radiographic improvement or disappearance resulted in deferred or nondiagnostic biopsy, with later confirmation of PCNSL. Steroid use and vanishing tumor were modeled using univariable logistic regression.

RESULTS

We identified 162 cases of PCNSL, of which 103 patients (63.6%) received steroids prior to biopsy. Twenty-three had vanishing tumor: 11 with deferred biopsies, 12 with non-diagnostic biopsies. Twenty-two of the 23 received steroid. Mean cumulative dose, in dexamethasone equivalents, was 555 + 704 mg prior to nondiagnostic/deferred biopsy (N=17) compared to 186 + 376 mg prior to successful biopsy (N=76) (Wilcoxon p< .001). Median time to recurrence after deferred or non-diagnostic biopsy (N=21) was 53 days (range: 8–648); two cases never recurred. Steroid use increased the risk of vanishing tumor by 14% per 100 mg dexamethasone equivalent (95% CI of odds ratio [1.03–1.29], p=0.02).

CONCLUSION

Vanishing tumor phenomenon is common in PCNSL, delays diagnosis, and is driven by steroid use.
EXTH-13. POTENT ANTICANCER EFFECTS OF A NEW WEARABLE NONINVASIVE ONCOMAGNETIC DEVICE: CELLULAR MECHANISMS OF ACTION
Authors: Helekar Santosh , Hambarde Shashank , Baskin David , Sharpe Martyn
Published: December 2020

Oscillating magnetic fields (OMF) produced by a new device with rotating magnets produces rapid apoptosis of patient derived glioblastoma (GBM) cells in culture. We have proposed that this is due to a sequence of events triggered by the well-established mT-range magnetic influence on the radical electron pair mechanism in the mitochondrial respiratory electron transport chain (ETC). Here we present results of preclinical studies in support of this mitochondrial hypothesis, accounting for the oncolytic effects of OMF. We tested a range of in vitro treatment protocols, involving changes in frequency and timing of OMF, to arrive at an optimally effective set of parameters. After hours of exposure to this optimized intermittent pattern of OMF killed not only patient derived GBM cells, but cells of 4 other malignant tumors in a cell culture dish. This treatment was not lethal to normal human astrocytes, bronchial epithelial cells, and B lymphocytes. Exposure to static magnetic fields and continuous OMF did not produce any oncolysis. The oncolytic effect of OMF was potentiated by compounds that enhance mitochondrial metabolism, e.g. β-hydroxybutyrate. The underlying cellular mechanism of OMF action involved complete arrest of ETC-dependent consumption of oxygen, accelerated upregulation of the levels of reactive oxygen species, opening of the mitochondrial membrane permeability transition pore, and disruption of the mitochondrial network, leading to caspase-dependent apoptosis of cancer cells. Daily treatment in a late-stage mouse model consisting of human GBM xenografts implanted into the brains of immunocompromised mice produced significant survival benefit. These findings document the potent oncolytic effects of OMF and specific mechanisms of action that will likely provide a novel and powerful treatment against GBM and a wide range of other solid malignant tumors. Clinical trials of this therapy are underway at our institution.
EXTH-18. ENGINEERED EXOSOMES AS GENE DELIVERY TOOLS FOR THE TREATMENT OF GLIOBLASTOMA
Authors: McDonald Malcolm , Hossain Anwar , Momin Eric , Hasan Irtiza , Singh Sanjay , Adachi Satoshi , Gumin Joy , Ledbetter Daniel , Daou Marc , Gopakumar Sricharan , Phillips Lynette , Kerrigan Brittany Parker , Lang Frederick
Published: December 2020

Although we previously showed that exosomes are capable of delivering anti-glioma microRNAs (miRs) to brain tumors (Lang et al. 2018), our studies revealed significant opportunity to 1) improve packaging and delivery efficiency of exosomes and 2) expand the repertoire of anti-glioma miRs. We hypothesized that incorporation of viral proteins into exosomes would enhance miR packaging and cell entry. To test this hypothesis, we engineered exosomes that express retroviral Gag and VSVg proteins (eExos). Specifically, HEK293T cells were transfected with Gag, VSVg, and with Cre-recombinase containing plasmid (pCre) to generate eExos-pCre. After 48hrs eExos-pCre were isolated by differential ultracentrifugation. Western analyses verified Gag and VSVg in eExos-pCre, and PCR documented pCre in these exosomes. Next, U87 cells harboring a dsRed-eGFP-loxP reporter-gene were treated with eExos-pCre or control exosomes. Flow cytometry demonstrated that eExos-pCre resulted in 82% conversion of red cells to green, compared with controls (2% conversion), verifying the effectiveness of eExos to deliver plasmids containing anti-glioma agents. To identify effective anti-glioma miRs, we conducted a high-throughput screen of 539 miRs against 7 glioma stem cell lines (GSCs) and identified miR-124-2, miR-135-a-2, and Let7i as the most potent anti-glioma miRs. We then studied the ability of eExos to package and deliver plasmids of these miRs either singly (eExos-miR-124, eExos-miR-135, eExos-miRLet7i) or as a tri-cistronic plasmid (eExos-miR-124-135-Let7i). Although eExos-miR-124, eExos-miR-135, and eExos-miRLet7i significantly decreased in vitro proliferation in all three GSCs (p< 0.01), eExos-miR-124-135-Let7i were most effective (p< 0.001). In in vivo studies, mice harboring GSC231 gliomas were injected with each of the eExos-miRs. Most significant improvement in survival was seen with eExos-miR-124-135-Let7i (median 75 versus 32.5 days for controls, p< 0.001). We conclude that eExos are a novel delivery strategy for human gliomas and that a tri-cistronic plasmid of miR-124-135-Let7i is highly effective against GBM and worthy of clinical translation.
EXTH-19. EVALUATING THE ANTI-TUMOR EFFECT OF A NOVEL THERAPEUTIC AGENT, MAGMAS INHIBITOR, IN MALIGNANT GLIOMA
Authors: Di Kaijun , Du Senjie , Lepe Javier , Nandwana Nitesh , Das Bhaskar , Bota Daniela
Published: December 2020

BACKGROUNDS

Glioblastoma (GBM) is an aggressive infiltrative brain tumor, and has an extremely poor prognosis despite the use of multiple treatment modalities, including surgery, radiation, and chemotherapy. Meanwhile, mitochondrial changes represent a significant part of cancer cell biology since cancer cells must survive and adapt to challenging microenvironments, specifically in conditions where tumor growth makes oxygen and glucose scarce. As GBM is characterized by extensive hypoxia-induced phenotypic changes such as abnormal vascular proliferation and necrosis, regulation of mitochondrial function could be a novel approach for treating GBM that currently lacks effective therapies. Magmas (mitochondria-associated protein involved in granulocyte-macrophage colony-stimulating factor signal transduction) is a nuclear gene that encodes for the mitochondrial import inner membrane translocase subunit Tim16. We previously demonstrated that a novel Magmas inhibitor, BT#9, significantly exerted anti-tumor effect in glioma in vitro, and may cross the blood brain barrier in vivo, indicating that Magmas inhibitor may be a new chemotherapeutic agent for the treatment of GBM.

METHODS

In this study, the antitumor effect of Magmas inhibitor BT#9 was tested in an orthotopic xenograft model of human GBM. The molecular mechanism of BT#9 was investigated using glioma cell lines.

RESULTS

The mice were tolerated to BT#9, and there was no statistical difference in the weight of animals between the control and MTD (Maximum-tolerated Dose, 50mg/kg) groups. The immunocompromised mice, intracranially implanted with human D-54 GBM xenografts, survived significantly longer than the controls (P< 0.5) when treated with BT#9 at MTD. In vitro study showed that the MAP kinase pathways are involved in BT#9-induced tumor suppression.

DISCUSSION

This is the first study on the role of Magmas in glioma in vivo. Our findings suggested that Magmas plays a key role in glioma survival and targeting Magmas by Magmas inhibitor has the potential to become a therapeutic strategy in glioma patients.
EXTH-25. THE CSF PENETRATION OF THE PROCASPASE-ACTIVATING COMPOUND (PAC-1) IN COMBINATION WITH TEMOZOLOMIDE (TMZ) IN A NONHUMAN PRIMATE CSF ACCESS MODEL
Authors: Lester McCully Cynthia , Shankarappa Priya , Garcia Rafael Cruz , Peer Cody , Zakharov Alexander , Fischer James , Lyubimov Alexander , Hergenrother Paul , Thomas Marvin , Figg William , Warren Katherine
Published: December 2020

BACKGROUND

The synergistic activity of temozolomide (TMZ) administered in combination with procaspase-activating compound (PAC-1) has been reported in pre-clinical mouse models and canine patients, leading to clinical trials in adults with glioblastoma. To optimize pediatric clinical trial design, a translational pharmacokinetic CSF penetration study was conducted using a pre-clinical nonhuman primate non-tumor bearing CSF access model with TMZ and PAC-1 administered alone and in combination.

METHODS

Four male rhesus macaques with CSF lateral ventricular reservoirs received PAC-1, 15 mg/kg orally [Human Equivalent Dose (HED) 558 mg/m2/day] or TMZ, 1-hr IV infusion, 7.5 mg/kg (HED 150 mg/m2) as single and combination agent administration. Paired plasma and CSF samples were collected for 0–96 hours. PAC-1 and TMZ were quantified by LC-MS/MS. Pharmacokinetic parameters were calculated using noncompartmental methods. Statistics were determined via Mann-Whitney test.

RESULTS

(Mean ± Standard Deviation): For TMZ: Plasma AUC0-24 (hr*ng/ml) single agent (n=4): 28590 ± 4888 and in combination (n=4): 32736 ± 10147. CSF AUC0-24 (hr*ng/ml) single agent (n=4):14406 ± 1279 and in combination (n=4):15614 ± 1767. CSF penetration (% AUCCSF: AUCPLASMA) single agent: 50.9% ± 2.2 and in combination:49.6% ± 8.4. For PAC-1: Plasma PAC-1 AUC0-24 (hr*ng/ml) single agent (n=4): 2556 ± 2157 and in combination (n=4): 1947 ± 1311. CSF PAC-1 AUC0-24 (hr*ng/ml) single agent (n=2): 8.7 ± 1.1 and in combination (n=3):12.9 ± 10.2. CSF penetration single agent: 0.2% ± 0.03 and in combination: 0.4% ± 0.38. CSF PAC-1 tlag and Tmax pharmacokinetic parameters decreased with concurrent TMZ administration.

CONCLUSIONS

In this non-tumor bearing pre-clinical nonhuman primate model the CSF penetration of PAC-1 was low and not notably affected by the concurrent administration of TMZ. TMZ CSF penetration for single administration was within previously reported ranges and also appeared unaffected when administered in combination with PAC-1.