Immunopathology of Central Nervous System Tumors

Abstract

The central nervous system (CNS) is characterized by unique immune biology. Distinct mechanisms of CNS immune surveillance and activation have important implications in tumor development as CNS tumors are known to evade anti-tumoral immunity, and may also contribute to immunosuppression. Multiple cell-surface and secreted mediators, expressed in both CNS tumor cells and responding immune cells, have been shown to influence the immune response to CNS tumors. In this review we provide an overview of CNS tumor immune escape and immunosuppression, highlighting the cellular and molecular features associated with both CNS tumors cells and responding immune cells. In this context, we discuss of the role of the M1 and M2 tumor associated macrophage phenotypes, myeloid derived suppressor cells, regulatory T-cells, as well as many immunomodulatory cytokines. Additionally, recent insights into the STAT-3 intracellular signaling pathway and the presence of active human CMV infection in the context of CNS tumor development are discussed.