Expression of COX-2 in Gastrointestinal Cancer: As a Target for Cancer Prevention and Therapy (3) : Esophageal Cancer and COX-2

Cyclooxygenase-2 (COX-2) derived prostaglandin (PG) E_2 is concerned with multiplication of intestinal cancer, in particular colorectal cancer, and has attracted attention as a preventive or therapeutic target of cancer. In the esophagus, COX-2 overexpression is reported in Barrett\u27s epithelium, esophageal adenocarcinoma and squamous cell carcinoma. It has been suggested that patients with high COX-2 expression have poor prognosis. In squamous cell carcinoma of the esophagus, COX-2 expression is detected in the stage of dysplasia, and its expression is accompanied by enhanced proliferation activity and accumulation of p53. Compared with adenocarcinoma, however there is little correlation with clinicopathological factors. In a duodeno-gastric reflux rat model, COX-2 inhibitor can control the generation of cancer without inhibition of Barrett\u27s esophagus. In a chemical carcinogenesis model, there are two conflicting reports about the effect of COX-2 inhibitor on the incidence and size of tumor. Since in vitro studies have shown that COX-2 inhibitor can block the proliferation of Barrett\u27s derived cells and squamous carcinoma derived cells, COX-2 inhibitor is expected to have a preventive or therapeutic effect. Based on the results of clinical use of COX-2 inhibitor, its potential as cancer revention in patients with reflux esophagitis or Barrett\u27s esophagus and as neoadjuvant therapy before surgery for esophageal cancer is suggested