Increased numbers of MDSCs in patients with lung cancer may inhibit the generation of protective immune CD8+ T cells, and the highly expressed iNOS and L-arginase I (Arg-1) of MDSCs promote the downregulation of CD3ζ chain expression of CD8+ T cells and inhibit the immune function of CD8+ T cells [78]. This evidence concerns the gene NOS2 and lung carcinoma.