Cyclo-oxygenase-2 expression in Barrett's oesophageal carcinogenesis: an immunohistochemical study.
BACKGROUND
The incidence of Barrett's oesophageal adenocarcinoma is increasing more rapidly than any other malignancy in industrialized countries. Cyclo-oxygenase-2 appears to play an important role in gastrointestinal carcinogenesis. Previous studies on cyclo-oxygenase-2 expression in Barrett's oesophageal carcinogenesis have utilized tissue samples obtained from different patients. We sought a definitive comparison of cyclo-oxygenase-2 expression in the sequence of Barrett's metaplasia-dysplasia-adenocarcinoma within the same patients.


METHODS
Paraffin-embedded oesophago-gastrectomy specimens from 20 patients, containing successive stages of Barrett's metaplasia, high-grade dysplasia and adenocarcinoma, were analysed for cyclo-oxygenase-2 expression by immunohistochemistry.


RESULTS
Cyclo-oxygenase-2 was constitutively expressed in the basal layers of cells in the adjacent normal squamous oesophageal epithelium, but a higher cyclo-oxygenase-2 expression was observed in Barrett's metaplasia. A further increase in cyclo-oxygenase-2 expression was detected in high-grade dysplasia, but cyclo-oxygenase-2 was decreased in adenocarcinoma tissue, regardless of its stage or level of differentiation.


CONCLUSIONS
Cyclo-oxygenase-2 expression is progressively increased when squamous oesophageal epithelium develops into Barrett's metaplastic epithelium and then into high-grade dysplasia, but appears to decrease when adenocarcinoma develops. These findings may be significant for an effective chemo-prevention strategy with selective cyclo-oxygenase-2 inhibitors.
Cheong
E
E
General Surgery Department, Norfolk and Norwich University Hospital, Colney, UK.
Igali
L
L
Harvey
I
I
Mole
M
M
Lund
E
E
Johnson
I T
IT
Rhodes
M
M
D000230:Adenocarcinoma / Q000378:metabolism*; D001471:Barrett Esophagus / Q000378:metabolism*; D051546:Cyclooxygenase 2; D004848:Epithelium; D004938:Esophageal Neoplasms / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007527:Isoenzymes / Q000378:metabolism*; D008565:Membrane Proteins; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*
D007527:Isoenzymes; D008565:Membrane Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases