Thus, although the total number of putative terminal anti-tumor CD8+ T cell effectors was 13.7-fold higher in GL261-CIITA tumors compared to GL261 parental tumors, the ratio of CD8+ T cells to FoxP3+ T cells was lower in GL261-CIITA tumors (CD8+/FoxP3+: mean = 1.8, SD = 1.5) than in GL261 parental tumors (CD8+/FoxP3+: mean = 3.5, SD = 3.2). This evidence concerns the gene CIITA and neoplasm.