Immunotherapy and checkpoint inhibitors for gliomas

Abstract

Glioma treatments are faced with challenges, including the inability to fully eliminate cancer stem cells, the immunosuppressive tumor microenvironment, and the blood brain barrier. Although progress has been made with surgical, radiation, and chemotherapies, prognosis for patients remains poor. Rapidly emerging immunotherapies may be able to address the challenges that conventional techniques cannot. Immunotherapies manipulate the patient’s immune system to selectively combat malignancies. Therapies often work to enhance T-cell and natural killer (NK) cell function, which can both eliminate tumor cells and enhance remission. Vaccines encourage in vivo development of anti-tumor T-cells and NK cells, while adoptive transfer techniques focus on engineering immune cells ex vivo before reintroducing them to patients. Vaccine and adoptive transfer therapies have been shown to induce enhanced immune responses in patients but have not always correlated with improved outcomes, likely because of the tumor immunosuppressive microenvironment. Checkpoint inhibitors can impair these tumor immunosuppressive capabilities. Although no one treatment has been able to consistently eliminate gliomas and maintain remission, combinations of vaccines or adoptive transfer techniques in conjunction with immune checkpoint inhibitors offers promise.