Specific COX-2 inhibitors, such as NSAIDs, may reduce the risk and improve the prognosis of carcinogenesis of several forms of cancer, including colon cancer, by inhibiting PGE2 synthesis. In order to successfully use COX-2 inhibitors in clinical applications to colorectal malignancies and other types of cancer as well, we must work to develop a protocol. Here, PTGS2 is linked to cancer.