The treated mice also had a higher ratio of glutathione to glutathione disulfide, the molecule that glutathione becomes after it neutralizes free radicals. These findings suggest that when the body is given extra antioxidants, its tumor cells get to keep more of the antioxidants that they already make themselves. The cells can store the surplus, improving their ability to survive damage. This idea is supported by work that shows some genes that drive cancer growth turn on other genes that make intrinsic antioxidants.