Next, to evaluate the efficacy of antigen-specific effector and memory CD8+ T cells, we tested an in vitro model, in which only OVA-specific T cells were expanded by treatment with an OVA peptide, and it was hypothesized that only the expanded and activated OVA-specific CD8+ T cells would then be able to exert specific cytotoxic activity against OVA-expressing target cancer cells [47,48]. This evidence concerns the gene CD8A and cancer.