MDSC exert different pro-tumor activities that include the induction of angiogenesis through (i) the production of MMP-9, prokineticin 2 and VEGF, (ii) the promotion of metastasis by producing arginase or inducible nitric oxide synthase (iNOS) and (iii) the inhibition of T cell functions through immunosuppressive cytokines, typically TGF-β and IL-10 [82,83]. The gene discussed is NOS2; the disease is neoplasm.