Role of oxidative stress in the pathogenesis of cancer

Carcinogenesis is a complex multi-step process depending on several endogenous and exogenous factors. A large number of evidences highlights the important role of oxidative stress in cancer development and progression. Oxidative stress occurs as consequence of the cell accumulation of reactive oxygen species (ROS) or reactive nitrogen species (RNS). ROS and RNS are generated by several different insults (i.e. UV light, inflammation, air pollution, etc.). Physiologically, reactive oxygenmetabolites react with several bio-molecules such as lipids, nucleic acids and proteins, but when their amount is excessively increased a permanent structural and/or functional modification of the biological molecules may occur. This mechanism represents the main way by which the products of oxidative stress may induce carcinogenesis. On the other hand, since oxidative stress is caused by an imbalance between the production of reactive oxygen and cell ability to readily detoxify the reactive intermediates or easily repair the resulting damage, another strategy to promote cancer is linked to the less antioxidant capacity of an organism, too. In this chapter we describe the role of oxidative stress in cancer development and progression, focusing mainly our attention on the mechanisms and molecules deregulated during oxidative damage, knowledge that could be useful for improvement of anticancer gene therapy.