Objective—To evaluate expression of cyclooxygenase
(COX)-1 and COX-2 in the urinary bladder epithelium of
clinically normal dogs and in transitional cell carcinoma
cells of dogs.
Animals—21 dogs with transitional cell carcinoma of
the urinary bladder and 8 dogs with clinically normal
Procedure—COX-1 and COX-2 were evaluated by
use of isoform-specific antibodies with standard
Results—COX-1, but not COX-2, was constitutively
expressed in normal urinary bladder epithelium; however,
COX-2 was expressed in neoplastic epithelium
in primary tumors and in metastatic lesions of all 21
dogs and in new proliferating blood vessels in 3 dogs.
Also, COX-1 was expressed in the neoplastic cells.
Conclusions and Clinical Relevance—Lack of
expression of COX-2 in normal bladder epithelium and
its substantial expression in transitional cell carcinoma
cells suggest that this isoform may be involved in
tumor cell growth. Inhibition of COX-2 is a likely
mechanism of the antineoplastic effects of non
steroidal antiinflammatory drugs. (Am J Vet Res