NOS2 and neoplasm: Collectively, these results indicated that moderate levels of iNOS are beneficial for tumor glycolysis and proliferation by producing nitric oxide at levels slightly above physiological condition (below 100 nM); and excess iNOS, which may be present in pathological conditions such as acute inflammation and reactive oxygen stress (ROS), is detrimental to glycolysis and leads to cytotoxicity of ovarian cancer cells.