CD8A and central nervous system cancer: To determine possible associations between the frequencies of certain lymphocyte subpopulations and the OS of patients with glioma, patients with grade 3 and grade 4 glioma were segregated into groups having low or high frequencies of different lymphocyte subpopulations such as CD3+/CD4+ helper T cells, CD3+/CD8+ cytotoxic T cells, CD3−/CD56+, CD56+/CD94+, and CD56+/CD69+ NK cells.