Figure 1: The incidence of cancer increases with aging. A main source of damage for cells originates from the cellular metabolism through the production of reactive oxygen species, ROS, which ultimately cause macromolecular damage, including DNA damage. This endogenous damage is thought to fuel aging as well as cancer. Those mechanisms that diminish to generate endogenous damage are calorie restriction, antioxidant mechanism, p53, SIRT1 and FOXO3a downstream signalling and KLOTHO hormone secretion protect cells from aging and cancer, in the other way their deregulation promote cells to aging and cancer.