Anti-tumor CD8+ T cells are also suppressed by the depletion of arginase and tryptophan from the TME after upregulation of secretion of nitrous oxide synthase and indoleamine 2,3-dioxygenase (IDO) by myeloid-derived suppressor cells (MDSCs) (16), or by the presence of a large amount of regulatory T cells (Tregs) compared to other cancers (17), and other immunosuppressive cells such as M2 TAM or neutrophils, both associated with poor survival (18). The gene discussed is CD8A; the disease is neoplasm.