Tumor MDSCs can restrain the activities of both non-specific and antigen-specific T-cells, which are more immunosuppressive than MDSCs, in the spleen that only suppresses antigen-specific CD8+ T cells; this is mostly due to the increased arginase activity and nitric oxide (NO) production as a result of regulation by HIF-1α [49]. Here, CD8A is linked to neoplasm.