Expression of COX-2 in Gastrointestinal Cancer: As a Target for Cancer Prevention and Therapy (2) : Gastric Cancer and COX-2

Recent studies have demonstrated that increased amount of prostaglandin E_2 (PGE_2) produced by overexpression of cyclooxygenase-2 (COX-2)/microsomal PGE synthase-1 (mPGES-1) is involved in tumor proliferation. In addition, relationships with the epidermal growth factor (EGF)/mitogen activated protein (MAP) kinase signal pathway related to cell proliferation and Akt/protein kinase B (PKB) related to resistance of apoptosis are being clarified. Association of COX-2 with gastric cancer has not been established as clearly as in colon cancer. However, increased expression of COX-2 in gastric cancer was confirmed, and in cell culture or animal models, influence of COX-2 on tumor proliferation was indicated. Thus, the usefulness of COX-2 inhibitor in treatment has been demonstrated. However, in precancerous lesions of gastric cancer, COX-2 expression is controversial and the usefulness of COX-2 inhibitor has not been demonstrated. Further studies about COX-2 and gastric cancer including clinical trials are needed and also more studies should be performed about other PGE_2 related molecules as well as COX-2