ROS, produced by various biochemical and physiological oxidative processes in the body, are also associated with numerous physiological and pathophysiological processes. ROS play a major role in the pathogenesis of various human diseases. At low concentrations, ROS exhibit beneficial effects by regulating intracellular signaling and homeostasis; at high levels, however, ROS play a major role in the damage of proteins, lipids, and DNA. Antioxidant defense systems in the human body maintain the balance between the production and neutralization of ROS and include superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), and glutathione (GSH). However, imbalances between ROS and antioxidant defense systems lead to oxidative stress, which initiates carcinogenesis. ROS have also been implicated in the mediation of apoptosis in cancer cells. The increased level of mitochondrial ROS was shown to promote cell proliferation, cell survival, cell migration, and epithelial-mesenchymal transition through mitogen-activated protein kinase (MAPK) and RasERK activation, ROS also elevated the p66Shc protein level, ErbB-2 level for cell proliferation.


1.Prasad S, et al. Cancer Lett. 2017;387:95–105.