Cyclooxygenase-2 expression in early gastric cancer, intestinal metaplasia and Helicobacter pylori infection.
Cyclooxygenase (COX) is the crucial enzyme for synthesis of prostaglandins and occurs in two isoforms COX-1 and COX-2. Whilst COX-1 is constantly expressed in the gastrointestinal tract in large quantities and probably maintains mucosal integrity through constant generation of prostaglandins, COX-2 is induced principally during inflammation. In early gastric cancer and in intestinal metaplasia the expression of COX-2 in patients infected by Helicobacter pylori is increased in intestinal type compared to diffuse type gastric cancer and in intestinal metaplasia. In tumours of mixed type, COX-2 is also increased in the intestinal component compared to the diffuse component. Whilst there has been success of COX-2 inhibition for chemoprevention in colon cancer, a similar role in gastric cancer needs to be carefully assessed in the light of reported adverse effects and whether the precancerous condition, intestinal metaplasia, can truly regress.
Walker
Marjorie M
MM
Department of Histopathology, Faculty of Medicine, Imperial College School of Science, Technology and Medicine, St Mary's Campus, Norfolk Place, London W2 1PG, UK. mm.walker@ic.ac.uk
D051546:Cyclooxygenase 2; D016481:Helicobacter Infections / Q000201:enzymology; D016480:Helicobacter pylori; D006801:Humans; D007413:Intestinal Mucosa / Q000473:pathology*; D007527:Isoenzymes / Q000378:metabolism*; D008565:Membrane Proteins; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000201:enzymology* / Q000382:microbiology
D007527:Isoenzymes; D008565:Membrane Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases