CD8A and neoplasm: In addition to mediating tumor immunity by regulating immune cell proliferation, differentiation and the exercise of immune functions through diverse pathways, it has been proposed that lactic acid mediates the release of extracellular vesicles (EVs) from cancer cells, and that tumor-derived EVs inhibit various types of immune cytotoxicity, such as CD8 T-cells and NK-cells, as well as DC-mediated antigen presentation and enhance the immunosuppressive function of Tregs and MDSCs, thus promoting the immune escape of cancer cells (59).