Immunological analysis revealed that patients who abstained from dexamethasone during the vaccination period developed sustained circulating neoantigen-specific CD4+ and CD8+ T cell responses characterized by: enhanced memory T cell phenotypes, increased tumor-infiltrating lymphocytes (TILs) densities, and vaccine-induced T cell trafficking from peripheral circulation to intracranial tumor sites, collectively resulting in immunomodulation of glioma microenvironment. This evidence concerns the gene CD8A and central nervous system cancer.