Epigenetic regulation of gene expression by DNA methylation plays a central role in the maintenance of cellular homeostasis. Here we present evidence implicating the DNA methylation program in the regulation of hypoxia-inducible factor (HIF) oxygen-sensing machinery. We show that DNA methyltransferase 3a (DNMT3a) methylates and silences the HIF-2alpha gene (EPAS1) in normal cells. Epigenetic silencing of EPAS1 prevents activation of the HIF-2alpha gene program associated with hypoxic cell growth, thereby limiting the proliferative capacity of cells under low oxygen tension. Naturally occurring defects in DNMT3a, observed in primary tumours and malignant cells, cause the unscheduled activation of EPAS1 in early dysplastic foci. This enables incipient cancer cells to exploit the HIF-2alpha pathway in the hypoxic tumour microenvironment, which is necessary for the formation of cellular masses larger than the oxygen diffusion limit. Reintroduction of DNMT3a in DNMT3a-defective cells restores EPAS1 epigenetic silencing, prevents hypoxic cell growth, and suppresses tumour growth in vivo. In addition, restoring HIF-2alpha expression in DNMT3a-reintroduced cancer cells restores full tumorigenic potential, including the capacity to traverse the hypoxic barrier. These data support a tumour-suppressive role for DNMT3a as an epigenetic regulator of the HIF-2alpha oxygen-sensing pathway and the cellular response to hypoxia.

The phosphorylation of the Fujinami sarcoma virus transforming protein (FSV P140gag-fps) is complex, reversible and affects its tyrosine specific protein kinase activity and transforming function. The sites of phosphorylation within FSV P140gag-fps have been localized to various regions of the protein using partial proteolysis. The two major phosphotyrosine residues and a major phosphoserine residue are located in the C-terminal portion of the fps region, which contains the kinase active domain. A comparative tryptic phosphopeptide analysis of the gag-fps proteins of three FSV variants shows that the phosphotyrosine containing peptides have similar mobilities. To determine whether tyrosine phosphorylation affects protein function and to evaluate the substrate specificity of the protein kinase intrinsic to FSV P130gag-fps oligonucleotide-directed mutagenesis was used to change tyrosine-1073, the major site of P130gag-fps phosphorylation. Tyrosine-1073 was mutated to a phenylalanine and a glycine, amino acids that cannot be phosphorylated, and to the other commonly phosphorylated hydroxyamino acids, serine and threonine. Neither serine nor threonine were phosphorylated when substituted for tyrosine-1073 indicating a strict specificity for and oncogenic capacities. These data indicate that tyrosine phosphorylation stimulates the biochemical and biological activities of FSV P130gag-fps and suggest that tyrosine phosphorylation modulates protein function. Mutations within the putative ATP-binding site of P130gag-fps at lysine-950 destroy both its kinase and transforming activities, supporting the idea that the tyrosine kinase activity intrinsic to P130gag-fps is essential for its transforming function. The mutant protein was also shown to be phosphorylated at a second tyrosine site, which has been previously identified in wild-type P130gag-fps as a site exclusively phosphorylated in vivo. Phosphorylation of secondary tyrosine residues within a mutant protein devoid of intrinsic tyrosine protein kinase activity suggests that the FSV P130gag-fps may be a target for phosphorylation by cellular tyrosine specific protein kinases. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

Considerable evidence indicates that events at the cell surface play a central role in the regulation of growth of normal and neoplastic cells. It is possible that modification of the surface molecules might be, in part, responsible for the processes that accompany tumorigenesis. These surface molecules are termed TSTA (tumor specific transplantation antigens) and TAA (tumor associated antigens). The purpose of this study is to raise xenogeneic antiserum which can recognize TAA. This antiserum, then, can be used as a tool to enrich or purify the antigen in question. Using the antibody feedback inhibition method which has been developed in our laboratory, an antiserum directed toward membrane components of DBA/2 mastocytoma P815 cells was raised. This antiserum was found to be specific for tumor cell extracts and had no reactivity with comparable extracts of normal cells when tested by complement fixation. This antiserum was also capable of killing P815 cells in the presence of guinea pig complement but had no reactivity with another DBA/2 tumor or a variety of normal DBA/2 cell preparations. When mixed with varying numbers of tumor cells and injected intraperitoneally into either DBA/2 or B6D2 Fl mice, the antiserum demonstrated a protective effect by either prolonging survival time or, apparently facilitating complete removal from the body of tumor cells when low numbers of cells were injected. The antiserum was used to monitor the purification of tumor associated antigen (TAA) of P815 cells. Membrane extracts of both P815 and normal DBA/2J spleen and peritoneal exudate cells were subjected to DEAE fractionation and gel filtration, following which fractions were tested for reactivity with the anti-P815 antiserum. Fractions from P815 extracts shown to be enriched for the TAA were used to raise a second antiserum specific for the tumor. This antiserum was also shown to have specificity for P815 and none for normal DBA/2J cells by ⁵¹Cr release assays in the presence of guinea pig complement and by surface labeling using peroxidase labeled sheep anti-rabbit immunoglobulin after treatment of either P815 or normal cells with the antiserum. This second antiserum (anti-P815-2), when allowed to react with ¹²⁵I-labeled TAA-enriched fractions of the P815 membrane extracts and passed over Sepharose-protein A columns, permitted the isolation of a single major component, detectable on autoradiographs of gradient acrylamide gels. This component was not present in equivalent normal DBA/2 tissue extracts, nor was it detectable when these tests were repeated using an antiserum raised against normal DBA/2 membrane preparations. It was thus concluded that this material constituted a TAA of the P815 mastocytoma. Then this major band was cut, eluted and used in CFA to immunize a rabbit. Three immunizations were needed to get antiserum which was specific to P815 cells and membrane extracts. P815 cells treated with this last antiserum were resistant to lysis by syngeneic cytotoxic cells but they were not when allogeneic cytotoxic cells were used. On the other hand, rabbit anti DBA/2 as well as mouse anti H-2d serum also blocked the syngeneic killing as well as having a blocking effect in the allogeneic killing. This suggests that this antiserum recognizes membrane molecules which are important for recognition by syngeneic cytotoxic cells. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

Neuroendocrine tumors (NETs) are a rare type of malignancy, however, their incidence and prevalence have markedly increased over the past several decades. Gastroenteropancreatic neuroendocrine tumors (GEP-NETs), NETs of the gastrointestinal (GI) tract, account for the majority of these tumors. Data from the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute (NCI), as well as from multiple cancer registries in Canada and Europe, indicate that the small intestine is one of the most common primary sites of GEP-NET development in Caucasian populations. Smaller studies from Asian countries, however, report a significantly lower proportion of small intestinal NETs (SI-NETs) in those countries’ populations. Interestingly, this finding persists in a study of Asians living in the United States, which, therefore, may suggest that genetics, and not environment, play a predominant role in driving this difference. Multiple studies exploring the genetics of SI-NETs in Caucasians have been published and have identified several genetic alterations implicated in tumorigenesis. However, the most consistently reported finding is chromosome 18 loss of heterozygosity (chr18 LOH), which has been detected in 61-78% of SI-NETs. Unfortunately, these studies have yet to be performed in a strictly Asian cohort. The proposed study, therefore, is a multicenter, cross-sectional study that will compare the proportion of SI-NETs with chr18 LOH in Asian versus Caucasian populations by performing a fluorescence in-situ hybridization (FISH) analysis of SI-NET tissue from both Asian and Caucasian samples. Overall, the results of this study may help to identify possible mechanisms driving the difference in proportion of SI-NETs between Asians and Caucasians, which in turn, may help to better characterize the genetic events leading into SI-NET tumorigenesis.

Head and neck cancers represent a group of tumors with two different etiologies. The first type is associated with the viral HPV infection, the second one is virus-independent and it is associated with smoking and alcohol consumption as two main risk factors. Numerous studies show that HPV-positive tumors are more frequent in younger patients, as well as that the prognosis and overall survival of these patients is remarkably better. Therefore, the modification of the treatment is considered. For this, however, specific, sensitive and clinically relevant biomarkers for accurate identification of tumor etiology is needed. Suitable candidates for such biomarkers are miRNAs, small non-coding regulatory molecules stable in archived samples, that have been shown as differentially expressed in human cancers and the expression pattern seems specific for tumors of different origin. The submitted thesis focuses on miRNA profiling in HPV-positive and HPV-negative tonsillar tumors and cervical carcinomas with the aim to find out the differences between regulation of important carcinogenetic pathways of tumors of viral and non-viral etiology. Our data have shown very large heterogeneity of the miRNA expression profiles of these tumors. Despite the well characterized and uniform samples collection, we have found...

Aufgrund verbesserter Diagnostik und Therapie sowie hierdurch verlängerter Überlebensraten kann der Bedarf an Unterstützungsmöglichkeiten bei Karzinompatienten in den nächsten Jahren steigen. Das Versorgungsangebot für Patienten und deren Angehörige muss sich dieser Entwicklung anpassen. Vor diesem Hintergrund wurden im Rahmen der vorliegenden Arbeit der Bedarf und die Inanspruchnahme von spezialisierten Unterstützungsmöglichkeiten (Palliativmedizin, Psychoonkologie, Sozialdienst und Ernährungsberatung) durch Gastrointestinal- und Bronchialkarzinompatienten im metastasierten und/oder rezidivierten Stadium analysiert. Dabei richtete sich das besondere Interesse auf den Zusammenhang zwischen den Faktoren Tumorentität, Geschlecht, Alter, Informationsbedarf, Symptomlast und der Inanspruchnahme der o.g. Unterstützungsmöglichkeiten. Grundlage dieser Arbeit waren Daten von 205 Patienten des „BUKA-Projektes“ aus dem Interdisziplinären Zentrum für Palliativmedizin des Universitätsklinikums Würzburg. 60% waren Gastrointestinaltumorpatienten und 40% Bronchialkarzinompatienten. Der Allgemeinzustand der Bronchialkarzinompatienten war signifikant schlechter. Die häufigsten genannten Symptome im ESASr waren Erschöpfung, Müdigkeit, Appetitverlust und reduziertes Allgemeinbefinden. Informationsbedarf zu Unterstützungsmöglichkeiten äußerten 67,3%, Informationsbedarf zur Erstellung einer Patientenverfügung hatten 35,3% der befragten Patienten. Der Bedarf an Unterstützung war im Bereich der Psychoonkologie (Cut-off DT ≥5) mit 50,5% am höchsten, somit zeigten etwas mehr als die Hälfte der Patienten eine interventionsbedürftige psychische Belastung. Gefolgt von der Ernährungsberatung (auffälliges aNRS) mit 42,4% und der spezialisierten Palliativmedizin (ESASr ≥7) mit 35,6 %. Bei der Inanspruchnahme lag die spezialisierte Palliativmedizin prozentual (19,5%) vor der Psychoonkologie (17,6%) und der Ernährungsberatung (17,1%). Abhängig von der jeweiligen Unterstützungsmöglichkeit haben 65,8 - 80,4% derer, die einen Bedarf gehabt hätten, diese nicht in Anspruch genommen. Einen statistisch signifikanten Einfluss auf die Inanspruchnahme von Unterstützungsmöglichkeiten ergab sich für folgende Faktoren: •Das Geschlecht (Frauen) und min. ein ESAS-Wert ≥7, stellten sich als Prädiktoren für die Inanspruchnahme der spezialisierten Palliativmedizin dar. •Das Geschlecht (Frauen), war Prädiktor für die Inanspruchnahme der Psychoonkologie. •Die Tumorentität (Gastro) sowie eine vorhandene Mangelernährung (auffälliger aNRS) waren Prädiktoren für die Inanspruchnahme einer Ernährungsberatung. Für die Faktoren Alter und Informationsbedarf konnte für die Inanspruchnahme der untersuchten Unterstützungsmöglichkeiten kein signifikanter Zusammenhang festgestellt werden. Auf die Inanspruchnahme des Sozialdienstes hatte keiner der untersuchten Faktoren einen signifikanten Einfluss. Zukünftige Forschung sollte untersuchen, welche Gründe für eine Nicht-Inanspruchnahme von Unterstützungsmöglichkeiten bestehen, um hierdurch die Versorgungskonzepte zu verbessern und dadurch mehr Patienten einen Zugang zu den für sie nötigen Unterstützungsbereichen zu ermöglichen. / Due to improved diagnostics and therapies survival rates of carcinoma patients it can be assumed that the need for supportive care may increase over the next few years. Thus, the care services for patients and their families have to adapt to this development. Against this background, the need and utilization of different support options (palliative medicine, psycho-oncology, social and nutritional counselling) were analyzed in gastrointestinal and bronchial carcinoma patients in metastatic and/or relapsed stage. The focus was given to the connection between the factors tumor entity, gender, age, information needs, symptom severity and the utilization of the above-mentioned support options. In this dissertation data from 205 patients of the "BUKA project" managed by the Interdisciplinary Center for Palliative Medicine of the University Hospital Würzburg were used. 60 percent were gastrointestinal tumor patients and 40 percent bronchial carcinoma patients. However, the general condition of the bronchial carcinoma patients was significantly worse. The most common symptoms mentioned in ESASr were fatigue, tiredness, loss of appetite and reduced general health. There was an information need concerning support options of 67.3 percent, whilst 35.3 percent of the interviewed patients needed information about Patient decree. The need for support was highest in psycho-oncology (cut-off DT ≥5), at 50.5 percent, followed by nutritional counseling (conspicuous/abnormal aNRS) with 42.4 percent and specialized palliative care (ESASr ≥7) with 35.6 percent. Regarding the utilization of support options, the palliative care (19.5 percent) ranked first, followed by psycho-oncology (17.6 percent) and nutritional counseling (17.1 percent). Depending on the different support options, 65.8 to 80.4 percent of those who were in the need of support options did not use them. The following factors have shown a statistically significant influence on the use of support options: •The gender (women) and at least an ESAS ≥7 presented themselves as predictors for the use of specialized palliative care. •The gender (women) was a predictor of psycho-oncology use. •The tumor entity (gastro) and existing malnutrition (conspicuous/abnormal aNRS) were predictors of nutritional counseling. No significant correlation was found concerning the factors age and information requirements and the use of the above-mentioned support possibilities. None of the investigated factors had a significant impact on the use of social services. Future research should investigate the reasons behind the disuse of support options, in order to improve care delivery and thereby allow more patients access to the support services they need.

Indiana University-Purdue University Indianapolis (IUPUI) / Radiation Therapy has been one of the most common techniques to treat various types of cancers, in particular is Head and Neck Cancer (HNC) which accounts for three percent of all cancers in the United States. During the treatment procedure, the patient is immobilized using immobilization devices such as the full head face mask, bite blocks, stereotactic frame, etc. to get accurate location of tumor. The disadvantage of these devices is that they are very uncomfortable to the patient especially people suffering from Post-Traumatic Stress Disorder (PTSD) and claustrophobia who cannot wear any confined masked system such as the full head mask or bite block during the treatment procedure. To mitigate this problem, there has been a lot of research in modifying such immobilizing devices without neglecting the accurate location of tumor. To this end, the research presented in this thesis focuses on developing a mask less system with accurately locating the position of tumor using the technique of coordinate transformation at the same time fulfilling the three important characteristics: • Comfort • Accuracy • Low price Such a system is comfortable to the patient because no confining mask system is used and we choose minimal contact points on the patient for fixing the patient. Traditionally, such type of cancer treatment is carried out in two stages: Diagnosis stage, which identifies the location of the tumor and the external markers and the Treatment stage where the tumor is treated with immobilization device being common in both the stages. In the new system, the immobilization devices vary at the two stages. The head position is monitored by using pressure sensor assembly where spring and pressure sensor setup detects the amount and direction of head deviation. We also prepare a customized 3D printed nose bridge part for extra referencing in the treatment room. Also, it is important that we use material for our immobilization devices which does not contain any metal and MRI compatible. Once the patient lies down on the treatment couch and is immobilized using the immobilization devices, then tumor location is calculated using the theory of coordinate transformation and transformation matrix in the Diagnosis and Treatment Stage. To validate the system, simulation of immobilization devices used in the new design was carried out using ANSYS Workbench 15.0 and LS-Dyna software’s Explicit Dynamics method. The simulation for the head-fixing device showed a deflection of ±0.1974 mm with respect to machine isocenter with a load of 60 N, which is lower than the customer requirement of ±3 mm with respect to machine isocenter of head deviation. The material used for the external markers for patient positioning was selected to be polyetheretherketone (PEEK) which is a radiolucent and widely used MRI compatible material. The system also takes into consideration the effect of weight loss, which is one of the drawbacks of the current systems. Although still in the development stage, this mask less system holds to be the next new variety of immobilization devices that are comfortable to the patient and less expensive to be implemented in future cancer treatment practices.

Hinter dem makroskopischen Bild einer Leukoplakie der Stimmlippen können sich verschiedene histopathologische Diagnosen, wie Hyper- oder Parakeratosen, unterschiedliche Dysplasieschweregrade oder ein invasives Karzinom, verbergen. Die Diagnose wird durch Exzision und histopathologische Beurteilung gestellt, gefolgt von einer Einteilung je nach Klassifikationssystem. Die existierenden Klassifikationssysteme sind in ihrer Aussagekraft bezüglich des Progressionsrisikos der verschiedenen Vorläuferläsionen und der daraus resultierenden Behandlungsempfehlung eingeschränkt. Die neue Einteilung der WHO aus dem Jahr 2017 unterscheidet „low-grade“ Dysplasien (ehemals Epithelhyperplasien und leichte Dysplasie) von „high-grade“ Dysplasien (ehemals mäßige- und schwergradige Dysplasien einschließlich des Carcinoma in situ). In der vorliegenden Arbeit wurden insgesamt 392 Patienten mit laryngealen Vorläuferläsionen aus der Klinik und Poliklinik für Hals-, Nasen- und Ohrenheilkunde des Universitätsklinikums Würzburg untersucht. Es waren insbesondere Männer im Durchschnittsalter von 59,9 Jahren betroffen. Zudem wird ein Raucheranteil von 85,1 % beschrieben. Im Verlauf entwickelten 57 Patienten (14,5%) ein invasives Karzinom. Mit steigendem Dysplasieschweregrad konnte eine zunehmende Entartungstendenz beobachtet werden. Patienten mit der initialen Diagnose einer Hyper- oder Parakeratose ohne Dysplasie (5,6%) bzw. einer leichtgradigen Dysplasie (8,9%) wiesen ein signifikant geringeres Entartungsrisiko auf als Patienten mit höhergradigen dysplastischen Veränderungen (p<0,001). Mäßiggradige (41%) und schwergradige Dysplasien (43,5%) bzw. Carcinomata in situ (54,5%) wiesen ein vergleichbar hohes Progressionsrisiko auf. Mäßige Dysplasien wurden in bisherigen Arbeiten bezüglich ihres Entartungsrisikos eher unterschätzt und oftmals mit den leichtgradigen Dysplasien in einer Gruppe zusammengefasst. Die aktuell erhobenen Daten weisen jedoch auf ein höher als ursprünglich angenommenes Entartungsrisiko hin, sodass aufgrund des hohen Progressionsrisikos die Aufnahme in die Kategorie der „high-grade“ Dysplasien gerechtfertigt scheint. Es lässt sich zudem beobachten, dass der Zeitraum in dem sich aus einer schwergradigen Dysplasie (45 Wochen) bzw. einem Carcinoma in situ (66,2 Wochen) ein Larynxkarzinom entwickelt, kürzer ist als der der mäßigen Dysplasien (117,1 Woche). Weitere Studien sind erforderlich, um die neu gewonnen Erkenntnisse zu validieren, das neue Klassifikationssystem der WHO 2017 in die klinische Praxis zu integrieren und ein besseres Verständnis der zugrunde liegenden Pathomechanismen zu entwickeln. / Behind the macroscopic appearance of vocal cord leucoplakia, many histopathological diagnoses can be hidden. Ranging from squamous cell hyperplasia to invasive carcinoma. These macroscopic features must always be determined by histological analysis and classified by a grading system. The existing classification systems used for laryngeal precursor lesions aren’t very promising concerning the validity of the risk of progression and the appropriate choice of treatment. The new WHO 2017 Classification distinguishes between low-grade (mild dysplasia) and high-grade dysplasia (moderate and server dysplasia / carcinoma in situ). For the present study a total of 392 patients were identified with laryngeal precursor lesions in the Ear, Nose & Throat Clinic of the University Hospital Würzburg. Especially men, with a mean age of 59,9 years, were affected. Additionally there were numerous smokers among the patients (85,1%). 57 patients (14,5%) developed invasive carcinoma. The rate of malignant transformation increased with the grade of dysplasia. Analysing the different groups of dysplasia, we found a significant lower risk of progression between patients with the initial diagnosis of hyper- or parakeratosis (5,6%) or mild dysplasia (8,9%) and patients with higher grades of dysplastic changes (p <0,001). Moderate dysplasia (41%), severe dysplasia (43,5%) and carcinoma in situ (54,5%) had similar progression rates. The group of moderate dysplasia has usually been underrated in former studies concerning the risk of progression. Mild and moderate dysplasia have often been considered as one group. The present data indicates a higher risk of the moderate dysplasia than initially suggested. It seems reasonable to subsume them in the group of high-grade dysplasia. The mean time interval between the diagnosis of severe dysplasia (45 weeks) or carcinoma in situ (66,2 weeks) and the development of laryngeal carcinoma is shorter than in patients with moderate dysplasia (117,1 week). Further studies are required to validate the reported results, to integrate the WHO 2017 Classification into clinical practice and to reach more awareness of the underlying pathological mechanisms.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

Glioblastoma (GBM) is the most common and aggressive brain tumor in adults which is characterized by extensive cellular and genetic heterogeneity. Even with surgery, chemotherapy with temozolomide, and radiation, tumor re-growth and patient relapse are inevitable. The extensive inter- and intra-tumoral heterogeneity (ITH) of recurrent GBM emerges from dysregulation at multiple -omic levels of the tumor. ITH exits at the cellular level due to a small subpopulation of chemo- and radio-resistant cells, called brain tumor initiating cells, which may drive GBM treatment resistance. Although a wealth of literature describes the biology of primary GBM (pGBM), we currently lack an understanding of how GBM evolves through therapy to become a very different tumor at recurrence, which may explain why therapies against primary GBM fail to work in recurrent GBM (rGBM). Thus, understanding the tumor evolution from a multi-omic perspective is critical for the development of effective therapeutic approaches. The current work focuses on identification and validation of novel predictive and prognostic biomarkers for rGBM using proteomics analysis on a large cohort of patientmatched pGBM-rGBM samples. This work allowed for detailed characterization of rGBM and its cognate TIME toward a better understanding of the molecular players driving recurrence which can be further used for instructing effective targeted and personalized therapies for the treatment of therapy-resistant GBM. In another part, we developed a novel immunotherapeutic modality called dual antigen T cell engager, to target Carbonic Anhydrase 9, a highly enriched hypoxia-inducible enzyme in GBM. We demonstrated that this immunotherapeutic strategy which allows for targeting tumor cells while recruiting and triggering T cells through simultaneously, is highly effective in eliminating tumor cells and can be a complementary component of combinatorial therapy for GBM patients. Altogether, this study provided key data for instructing novel and rational combinatorial polytherapeutic approaches for the treatment of therapy-resistant GBM. / Thesis / Doctor of Philosophy (PhD) / Cancer is the leading cause of death in Canada and Glioblastoma Multiforme (GBM) is the most common type of malignant adult brain tumor which is one of the difficult human cancers to treat. In spite of the multi-model therapy including surgery, chemotherapy, and radiation, tumor re-growth and patient relapse are inevitable. A wealth of literature describes the biology of treatment-naïve or primary GBM, but we currently lack an understanding of how GBM evolves through therapy to become a very different tumor at recurrence, which may explain why therapies against primary GBM fail to work in recurrent GBM (rGBM). Clinical trials have not shown significant survival advantages for GBM patients, due not only to the lack of biological characterization of the distinct landscape of GBM recurrence, but also due to our poor understanding of the tumor immune microenvironment (TIME), the immune cells surrounding the tumor that may somehow fail to attack it due to GBM cells’ ability to suppress the immune system and evade detection. To understand how GBM cells and the TIME evolve under therapeutic pressure, we performed proteomics analysis on a large cohort of primary-recurrent GBM patient samples, to further understand treatment failure and develop effective and empirical combinatorial poly-therapies for the treatment of therapy-resistant GBM. Besides, in the next part of this study we showed existence of few cells within the tumor, termed brain tumor initiating cells (BTICs) can alone drive tumor growth and cause therapy resistance. To be able to target these population of cells, we identified treatment resistant tumor associated markers (highly expressed cell surface proteins) on these cells and developed novel treatments using a new class of biologics, Dual Antigen T cell Engagers (DATEs), to target these tumor associated markers. DATEs act like a “molecular glue” that specifically binds the patient’s own naturally circulating T-cells (soldier cells of the immune system) to cancer cells. Once bound, the T-cells attack and kill the patient’s cancer cells. In this strategy, the abnormal expression of tumor surface proteins can be used as a handle to drive T cell-mediated cell death. We predict that the dual specific antibodies through this study could be used alone or in combination with existing drugs to treat recurrent GBM.