CD8A and neoplasm: In the core region of the KO tumors, we detected higher infiltrates of CD3+ T cells (WT = 5.76% ± 2.84% SD vs. KO = 9.08% ± 2.27% SD; p = 0.0325), proliferating CD3+Ki-67+ T cells (WT = 0.35% ± 0.28% SD vs. KO = 2.51% ± 0.85% SD; p ≤ 0.0001), CD8+ T cells (WT = 1.51% ± 1.26% SD vs. KO = 5.55% ± 2.835% SD; p = 0.0048) and Granzyme B+ cytotoxic cells (WT = 0.7% ± 0.42% SD vs. KO = 4.59% ± 4.59% SD; p = 0.0013) compared to the tumor tissue of WT.