Vitamin E is a major antioxidant and the primary defense against lipid peroxidation. It is particularly important in protecting the body's cells from free radical/oxidative damage. These prtotective benefits are achievable with supplemental intakes higher than what is normally consumed in the average diet.
From the FDA's website: "Some scientific evidence suggests that consumption of antioxidant vitamins may reduce the risk of certain forms of cancer. However, FDA has determined that this evidence is limited and not conclusive."