Systematic review: Cyclo-oxygenase-2 in human oesophageal adenocarcinogenesis.
BACKGROUND
Published in vitro and animal in vivo studies have demonstrated that cyclo-oxygenase-2 plays an important role during oesophageal adenocarcinogenesis. However, the extent to which these studies are directly relevant to events in the human lower oesophagus is questionable.


OBJECTIVE
To perform a systematic review of all available human studies that have evaluated levels of cyclo-oxygenase-2 expression during the progression from Barrett's metaplasia to oesophageal adenocarcinoma.


METHODS
A literature search was performed to identify all studies which qualitatively or quantitatively assessed cyclo-oxygenase-2 protein or gene expression in either Barrett's, dysplastic or adenocarcinoma tissue in humans.


RESULTS
A total of 27 studies met the inclusion criteria. There was general agreement that cyclo-oxygenase-2 was either absent or very weakly expressed in normal oesophageal squamous mucosa, but considerable disagreement regarding the presence of cyclo-oxygenase-2 in Barrett's and low-grade dysplasia. All studies agreed that high-grade dysplasia and adenocarcinoma expressed cyclo-oxygenase-2 to some extent although levels varied considerably between tissue samples.


CONCLUSIONS
There is conflicting evidence in the literature for cyclo-oxygenase-2 playing an important role in early oesophageal adenocarcinogenesis. Other non-cyclo-oxygenase-2 targets may account for the epidemiological data supporting the use of non-steroidal anti-inflammatory drugs in the chemoprevention of oesophageal adenocarcinoma.
Mehta
S
S
Department of Upper Gastrointestinal Surgery, Norfolk and Norwich University Hospital, Colney Lane, Norwich, UK.
Boddy
A
A
Johnson
I T
IT
Rhodes
M
M
D000230:Adenocarcinoma / Q000188:drug therapy / Q000201:enzymology*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use*; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D004938:Esophageal Neoplasms / Q000188:drug therapy / Q000201:enzymology*; D006801:Humans; D007150:Immunohistochemistry
D000894:Anti-Inflammatory Agents, Non-Steroidal; D051546:Cyclooxygenase 2