 Cancer has high morbidity and mortality due to poor prognosis and elevated levels of reactive oxygen species, ROS, are common hallmarks of cancer progression and resistance to treatment. Mitochondria contribute mainly in the generation of ROS during oxidative phosphorylation. Elevated levels of ROS have been detected in cancer cells due to high metabolic activity, cellular signalling, paroxysomal activity, mitochondrial dysfunction, activation of oncogenes, and increased enzymatic activity of oxidases, cyclooxygenases, lipoxygenases, and thymidine phosphorylases. Cells maintain intracellular homeostasis by developing an immense antioxidant system including catalase, superoxide dismutase, glutathione peroxidase, glutathione, and transcription factor N-RF2, reactive oxygen species mediated signalling pathways activate prooncogenic signalling which eases in cancer progression, angiogenesis, and survival. Targeting the ROS signal involved in cancer development is a new strategy in cancer treatment. This article was authored by Sima Kumori, Anil Kumar Badhana, Moroli Mohanji, and others. We are article.tv, links in the description below.