Differential expression of cyclooxygenase 2 in human colorectal cancer.
BACKGROUND
Experimental, clinical, and epidemiological studies have implicated mitogenic metabolites of arachidonic acid such as prostaglandin E(2) (PGE(2)) in colorectal carcinogenesis. Recently, cyclooxygenase 2 (COX-2) which catalyses the conversion of arachidonic acid to PGE(2), has displayed increased levels in human colorectal cancer.


OBJECTIVE
To evaluate whether there is differential COX-2 expression from different locations (caecum, ascending, transverse, descending, or sigmoid colon, and rectum) in human colorectal cancer.


METHODS
Protein levels of COX-2 were determined by western blot analysis in tumours and adjacent normal mucosa of 39 patients with colorectal cancer.


RESULTS
There was a notable overexpression of COX-2 protein in tumours located in the rectum (p<0.001) compared with other locations in the colon. Rectal tumours revealed elevated COX-2 protein levels in 18/20 cases compared with 4/19 colonic cases. No association between enhanced COX-2 protein expression in tumour tissue and Dukes's stages was found.


CONCLUSIONS
Results suggest that the differential COX-2 expression may be due to differences in gene regulatory factors affecting COX-2 expression and/or reflect secondary changes in tumour progression which may have clinical implications.
Dimberg
J
J
Department of Biomedicine and Surgery, Division of Cell Biology, Faculty of Health Sciences, Linköping, Sweden.
Samuelsson
A
A
Hugander
A
A
Söderkvist
P
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015153:Blotting, Western; D003110:Colonic Neoplasms / Q000737:chemistry; D015179:Colorectal Neoplasms / Q000737:chemistry*; D051546:Cyclooxygenase 2; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000032:analysis*; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis*; D011451:Prostaglandin-Endoperoxide Synthases / Q000032:analysis*; D012004:Rectal Neoplasms / Q000737:chemistry
D007527:Isoenzymes; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases