The study investigates the antioxidant function of the p53 tumor suppressor, which is typically known for its role in inducing growth arrest and apoptosis. The authors found that p53 also protects the genome from oxidation by reactive oxygen species (ROS), a major cause of DNA damage and genetic instability. In non-stressed cells, relatively low levels of p53 are sufficient to up-regulate several antioxidant genes, reducing intracellular ROS levels. Down-regulation of p53 leads to excessive DNA oxidation, increased mutation rates, and karyotype instability, which can be mitigated by incubating cells with the antioxidant N-acetylcysteine (NAC). Dietary supplementation with NAC prevents lymphomas in p53 knockout mice and slows down the growth of xenografts from A549 cells with inhibited p53. These findings suggest that p53 has a non-restrictive tumor suppressor function and that antioxidants may play a significant role in cancer prevention and treatment.The study investigates the antioxidant function of the p53 tumor suppressor, which is typically known for its role in inducing growth arrest and apoptosis. The authors found that p53 also protects the genome from oxidation by reactive oxygen species (ROS), a major cause of DNA damage and genetic instability. In non-stressed cells, relatively low levels of p53 are sufficient to up-regulate several antioxidant genes, reducing intracellular ROS levels. Down-regulation of p53 leads to excessive DNA oxidation, increased mutation rates, and karyotype instability, which can be mitigated by incubating cells with the antioxidant N-acetylcysteine (NAC). Dietary supplementation with NAC prevents lymphomas in p53 knockout mice and slows down the growth of xenografts from A549 cells with inhibited p53. These findings suggest that p53 has a non-restrictive tumor suppressor function and that antioxidants may play a significant role in cancer prevention and treatment.