CD8A and neoplasm: Immature Dendritic cells in the PTC microenvironment can secrete immunosuppressive cytokines, such as IL-10 and TGF- β, so as to inhibit the immune response and result in the development of PTC, while CD8+ T cells recognize tumor cells to express antigen and thus participate in the killing of tumor cells, exhibiting protective effects on PTC (25, 26).