Other genes involved in oxidative stress responses were also affected by the KD, including glutathione peroxidase 7 (Gpx7) and peroxiredoxin 4 (Prdx4), both of which play cellular protective roles [53,54], and are similarly regulated as Cox2 - i.e., showing higher expression in tumor vs. normal tissue when animals are fed a KD, but not when they are fed a SD. This evidence concerns the gene PTGS2 and neoplasm.