Mechanisms for the prevention of gastrointestinal cancer: the role of prostaglandin E2.

Carcinoma of the colon or rectum represents one of the most common malignancies worldwide with a higher prevalence in industrialized regions. Epidemiologic studies of individuals taking non-steroidal anti-inflammatory drugs (NSAIDs) have shown a significant reduction in colorectal cancer (CRC) mortality compared to those individuals not receiving these agents. NSAIDs inhibit the enzymatic activity of both isoforms of cyclooxygenase (COX-1 and COX-2), while COX-2-selective inhibitors have shown some efficacy in reducing polyp formation. COX-2-derived bioactive lipids, including the primary prostaglandin (PG) generated in colorectal tumors, PGE(2), are known to stimulate cell migration, proliferation and tumor-associated neovascularization while inhibiting cell death. Here we briefly review the role of NSAIDs in preventing CRC, as well as the proposed mechanism by which a COX-2-derived PG, PGE(2), promotes colon cancer.