NOS2 and neoplasm: These classically activated, pro-inflammatory M1 macrophages are characterized by high levels of pro-inflammatory cytokines, such as interferon-γ (IFN-γ), tumor necrosis factor alpha (TNF-α), interleukin 1 (IL-1), interleukin 6 (IL-6), produce inducible nitric oxide synthase (iNOS) and high reactive oxygen species (ROS) to promote bactericidal and anti-tumor activity (36).