title: Cyclooxygenase-2 expression in Helicobacter pylori-associated premalignant and malignant gastric lesions.
abstract: Expression of cyclooxygenase-2 (COX-2) in various stages of the Helicobacter pylori-associated gastric carcinogenesis pathway has not been elucidated. We investigated the distribution and intensity of COX-2 expression in premalignant and malignant gastric lesions, and monitored the changes after H. pylori eradication. Gastric biopsies from H. pylori-infected patients with chronic active gastritis, gastric atrophy, intestinal metaplasia (IM), gastric adenocarcinoma, and noninfected controls were studied. Expression of COX-2 was evaluated by immunohistochemistry and in situ hybridization. Endoscopic biopsies were repeated 1 year after successful eradication of H. pylori in a group of IM patients for comparing COX-2 expression and progression of IM. In all H. pylori-infected patients, COX-2 expression was predominantly found in the foveolar and glandular epithelium and, to a lesser extent, in the lamina propria. In the noninfected group, only 35% of cases demonstrated weak COX-2 expression. Intensity of COX-2 was not significantly different between the chronic active gastritis, gastric atrophy, IM, and gastric adenocarcinoma groups. In 17 patients with IM, COX-2 expressions in the epithelial cells and stromal cells were reduced 1 year after H. pylori eradication. However, the changes in COX-2 expression did not correlate with progression/regression of IM. Both premalignant and malignant gastric lesions demonstrate strong COX-2 expression. Successful eradication of H. pylori leads to down-regulation of COX-2 expression but failed to reverse IM at 1 year.
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong. joesung@cuhk.edu.hk
authors.forename: J J
authors.initials: JJ
authors.lastname: Sung
authors.forename: W K
authors.initials: WK
authors.lastname: Leung
authors.forename: M Y
authors.initials: MY
authors.lastname: Go
authors.forename: K F
authors.initials: KF
authors.lastname: To
authors.forename: A S
authors.initials: AS
authors.lastname: Cheng
authors.forename: E K
authors.initials: EK
authors.lastname: Ng
authors.forename: F K
authors.initials: FK
authors.lastname: Chan
mesh_terms: D000230:Adenocarcinoma / Q000201:enzymology* / Q000382:microbiology / Q000473:pathology; D051546:Cyclooxygenase 2; D015536:Down-Regulation; D005753:Gastric Mucosa / Q000201:enzymology* / Q000382:microbiology / Q000473:pathology; D016481:Helicobacter Infections / Q000201:enzymology* / Q000382:microbiology; D006801:Humans; D007124:Immunoenzyme Techniques; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins; D011230:Precancerous Conditions / Q000201:enzymology* / Q000382:microbiology / Q000473:pathology; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D013274:Stomach Neoplasms / Q000201:enzymology* / Q000382:microbiology / Q000473:pathology
chemical_list: D007527:Isoenzymes; D008565:Membrane Proteins; D012333:RNA, Messenger; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases