Immunologic specificity in glioblastoma: Antigen discovery and translational implications

Recent studies have highlighted the therapeutic potential of targeting tumor antigens (TAs) in glioblastoma (GBM). Several classes of TAs, such as tumor-associated, cancer testis, and tumor-specific antigens, have proven to be immunogenic and used safely in vaccines. Many of these vaccines have focused on tumor-associated or cancer testis antigens. However, tumor-specific antigens (TSA) present an ideal target due to the lack of tolerance and exclusive tumor expression, mitigating the risk of off-target effects. Most research on TSAs in GBM has aimed to uncover neoantigens, yet the dearth of shared neoantigens as well as the cost and labor-intensive process of identifying personal neoantigens have acted as barriers to treatment. A better understanding of the individual antigens spanning all three TA classes is important to improve the design of GBM antigen therapies and understand, fundamentally, the nature of immunologic specificity in glioma. We review the antigen classes in all cancers and how TAs are discovered. Then, we focus on the unique properties of GBM and the antigens that have been identified and used for therapy in GBM. Finally, we discuss translational considerations for future antigen-targeted treatments.