%A Perng,Powell %A Lim,Michael %D 2015 %J Frontiers in Oncology %C %F %G English %K Glioblastoma,glioblastoma multiforme (GBM),brain tumor,Tumor immunotherapy,cancer immunotherapy,Cancer immunosuppression,Glioma,IL-10,TGF-beta,PD-L1,immune checkpoints,myeloid derived suppressor cells,malignant glioma,Microglia,T regulatory cells,indoleamine 2,3-dioxygenase,Immune Privilege,CNS immune privilege,B7-H1 (PD-L1) %Q %R 10.3389/fonc.2015.00153 %W %L %M %P %7 %8 2015-July-06 %9 Review %+ Powell Perng,Department of Neurosurgery, School of Medicine, Johns Hopkins University,USA,pperng1@jhmi.edu %# %! Immunosuppressive Mechanisms of Malignant Gliomas: Parallels at Non-CNS Sites %* %< %T Immunosuppressive Mechanisms of Malignant Gliomas: Parallels at Non-CNS Sites %U https://www.frontiersin.org/articles/10.3389/fonc.2015.00153 %V 5 %0 JOURNAL ARTICLE %@ 2234-943X %X The central nervous system (CNS) possesses powerful local and global immunosuppressive capabilities that modulate unwanted inflammatory reactions in nervous tissue. These same immune-modulatory mechanisms are also co-opted by malignant brain tumors and pose a formidable challenge to brain tumor immunotherapy. Routes by which malignant gliomas coordinate immunosuppression include the mechanical and functional barriers of the CNS; immunosuppressive cytokines and catabolites; immune checkpoint molecules; tumor-infiltrating immune cells; and suppressor immune cells. The challenges to overcoming tumor-induced immunosuppression, however, are not unique to the brain, and several analogous immunosuppressive mechanisms also exist for primary tumors outside of the CNS. Ultimately, the immune responses in the CNS are linked and complementary to immune processes in the periphery, and advances in tumor immunotherapy in peripheral sites may therefore illuminate novel approaches to brain tumor immunotherapy, and vice versa.