One of the major regulatory components in the relationship between cancer and chronic inflammation is ROS that has an ability to affect the type, presence, and levels of inflammation-modulating factors such as activator protein 1 (AP-1), β-catenin/Wnt (wingless related integration site), HIF-1α (hypoxia-inducible factor-1 alpha), NF-κB, PPAR-γ (peroxisome proliferator-activated receptor gamma), p53, inflammatory cytokines, chemokines, and growth factors [27,33,34,35]. The gene discussed is FOS; the disease is cancer.