More importantly, we found a substantial increase in tumor-infiltrating CD8+ T cell density in MC38K tumors from circAtxn7CKO mice than those from WT littermates (Fig. 5I, J), as well as in cytotoxic cytokine IFN-γ production (Fig. 5K) and the expression of perforin and CD107a, markers related to cytotoxic activity (Supplementary Fig. 11K), but no significant effects on the exhausted phenotype (Supplementary Fig. 11L). This evidence concerns the gene PRF1 and neoplasm.