Glioblastoma (GBM) is uniformly fatal with an incidence rate of 2.99-3.23 per 100,000 people. Despite recent therapeutic advances, our understanding of tumor biology in GBM remains incurable with median survivals of less than two years. Critical unanswered questions contributing to this dismal prognosis that elude clarification through traditional analysis of human clinical material or small animal models include i) how does surgical trauma impact GBM development and adjacent brain tumor microenvironments, ii) what are the unique cellular and molecular properties of residual infiltrating tumor cells during disease progression, and iii) how do surgically induced selection pressures generate de novo molecular and cellular heterogeneity not present in unresected surgical samples. Development of a cure or at least a treatment that would provide significant quality of life improvements in GBM patients is ultimately limited by the lack of animal models that reproduce the hallmark features of GBM tumor. Typically, rodent models are used to study GBM; however, rodents differ vastly from humans (e.g., brain size and complexity), making surgical interventions difficult to simulate. By contrast, the mini- pig brain is remarkably like the human brain and its larger size permits relevant surgical and imaging studies. Therefore, we propose to develop a first-in-kind syngeneic (intact immune system) glioma model in mini-pigs to recapitulate hallmark features of human glioma. Development of this model will support studies heretofore impossible in rodent models or human patients. Thus far, we have established oncogene activated transformed pig glioma cell lines from pig brains and confirmed their tumorigenic capabilities in mouse models and onco- minipigs. In the proposed research, we will determine the optimum engraftment conditions of these oncogene activated transformed pig cells by implanting them into host pig brain under chronic vs transient immunosuppressive microenvironment. We will also study the impact of provincial treatment of anti-inflammatory and immune suppressive drugs. To eliminate any potential impact of immune activation between different donors and hosts, we will repeat the same approach to induce in vivo viral oncogenesis. The relevance of the proposed syngeneic pig model will be established through analysis of accepted hallmark MR imaging, stereotactic guided intracranial surgery, and pathology features of the human disease, followed by immune phenotyping. Development of a large animal glioma model is expected to facilitate new insight into human glioma biology. As a first step, we propose to test the hypothesis that mini-pig syngeneic glioma models will recapitulate key features of the human disease. Further, these models are expected to provide a robust new platform for future studies not possible in rodent models or practically achievable through analysis of patient-derived material. This includes, but is not limited to, the evaluation of...