PTGS2 and cancer: While the results of large chemoprevention trials thus far have not been encouraging, a 20-year follow-up study with aspirin, a non-steroidal anti-inflammatory agent that acetylates and inhibits COX-2, showed that the mortality rates from all solid cancers were 20% lower for those receiving aspirin, with adenocarcinoma being the most reduced (34%).255,256 This is strong evidence for the role of anti-inflammatory agents such as COX inhibitors in cancer prevention.