Cyclo-oxygenase-2 over-expression in sporadic colorectal carcinoma without lymph node involvement.
BACKGROUND
Cyclo-oxygenase-2 over-expression has been reported in most advanced human colorectal cancers.


OBJECTIVE
To assess the prevalence of cyclo-oxygenase-2 over-expression in non-advanced colorectal cancers, to investigate the correlation between cyclo-oxygenase-2 status and tumour clinicopathological features and molecular phenotype, and to determine the impact of cyclo-oxygenase-2 status on long-term clinical outcome.


METHODS
Sixty-one patients who had undergone surgery for colorectal cancer without lymph node involvement were evaluated retrospectively. Cyclo-oxygenase-2 expression was determined by immunohistochemistry. The tumour replication error phenotype was assessed by amplification of the two microsatellites, BAT-25 and BAT-26.


RESULTS
Thirty-six tumours were classified as cyclo-oxygenase-2 positive and 25 as cyclo-oxygenase-2 negative. No correlation was found between cyclo-oxygenase-2 over-expression and clinicopathological features or molecular phenotype. Cyclo-oxygenase-2 over-expression was an independent predictor of a poor prognosis. Indeed, the relative risk of tumour recurrence or death for patients with cyclo-oxygenase-2-positive tumours was 2.13 times that of patients with cyclo-oxygenase-2-negative tumours (P=0.008; 95% confidence interval, 1.22-3.73). This difference remained significant when post-operative deaths were censored in the multivariate analysis (P=0.014).


CONCLUSIONS
Cyclo-oxygenase-2 over-expression is not associated with tumour phenotype, but is indicative of a poorer clinical outcome in patients with non-advanced colorectal carcinoma.
D000368:Aged; D015179:Colorectal Neoplasms / Q000378:metabolism*; D051546:Cyclooxygenase 2; D004273:DNA, Neoplasm / Q000235:genetics; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins; D018895:Microsatellite Repeats; D009364:Neoplasm Recurrence, Local / Q000378:metabolism; D010641:Phenotype; D011379:Prognosis; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D012044:Regression Analysis; D012189:Retrospective Studies; D016019:Survival Analysis
D004273:DNA, Neoplasm; D007527:Isoenzymes; D008565:Membrane Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases