Oxidative stress and its role in cancer: a molecular perspective

Cancer development is a product of cellular growth and proliferation caused by DNA mutations, nevertheless, other processes are able to favor tumoral progression, such as the activity of reactive oxygen species (ROS) produced within cells as a result of different metabolic reactions. Oxidative stress is defined as an imbalance between free radicals and highly reactive metabolites synthesis and the antioxidant system capacity to eliminate these molecules. In this sense, the overproduction of free radicals is a typical feature of neoplastic cells that allows the promotion of cellular processes related to survival, proliferation, invasion, and metastasis. Furthermore, underlying mechanisms involved in malignant transformation can modify the antioxidant systems in charge of ROS elimination. However, cancer has the particularity of presenting a dual behavior in which both antioxidant or prooxidant activity within tumoral cells can predominate depending on the stage of the disease. As a consequence, many therapeutic efforts have been directed into the stimulation or inhibition of oxidant and antioxidant components in the tumor microenvironment. The aim of this review is to describe the role of oxidative stress in cancer biology and its therapeutic potential.