Toxins, radiation, and normal metabolic processes together generate molecular lesions in every one of our cells to the tune of 10,000 to 1,000,000 hits per day. Fortunately, most of these code faults are immediately patched up by sophisticated DNA repair mechanisms. Any undetected damage to tumor suppressor or other key metabolic genes usually causes such a stir that the apoptotic cycle is triggered and the cell gracefully bows out of the game. If and when that fails, the cell will present antigens from any mutated proteins to the immune system so that it can be eliminated before it can go rogue.