Immunohistochemical evaluation of cyclooxygenase expression in corneal squamous cell carcinoma in horses.
OBJECTIVE
To evaluate expression of cyclooxygenase (COX)-1 and COX-2 in the cornea, eyelid, and third eyelid of healthy horses and those affected with squamous cell carcinoma (SCC) by use of immunohistochemical techniques.


METHODS
15 horses with SCC involving ocular tissues and 5 unaffected control horses.


METHODS
SCC-affected tissues were obtained from the cornea (n = 5 horses), eyelid (5), and third eyelid (5). Site-matched control tissues were obtained from 5 horses unaffected with SCC. Tissue sections of affected and control cornea, eyelid, and third eyelid were stained immunohistochemically for COX-1 and COX-2 via standard techniques. Stain uptake was quantified by use of computer-assisted image analysis of digital photomicrographs.


RESULTS
Immunoreactivity for both COX-1 and COX-2 was significantly greater in equine corneas with SCC than in control corneas. No significant differences in COX-1 or COX-2 immunoreactivity were detected in eyelid and third-eyelid SCC, compared with site-matched control tissues.


CONCLUSIONS
Immunoreactivity for COX-1 and COX-2 is high in equine corneal SCC, possibly indicating that COX plays a role in oncogenesis or progression of this tumor type at this site. Pharmacologic inhibition of COX may represent a useful adjunctive treatment for corneal SCC in horses.
McInnis
Carey L
CL
Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri-Columbia, Columbia, MO 65211, USA.
Giuliano
Elizabeth A
EA
Johnson
Philip J
PJ
Turk
James R
JR
D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000662:veterinary*; D003315:Cornea / Q000201:enzymology* / Q000473:pathology; D051545:Cyclooxygenase 1 / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D005134:Eye Neoplasms / Q000378:metabolism / Q000662:veterinary*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006734:Horse Diseases / Q000378:metabolism*; D006736:Horses; D007150:Immunohistochemistry / Q000662:veterinary; D008099:Liver / Q000201:enzymology / Q000473:pathology; D008297:Male
D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2