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Expression of cyclooxygenase-2 by equine ocular and adnexal squamous cell carcinomas.
Abstract: To investigate whether cyclooxygenase-2 (COX-2) is expressed by equine ocular and adnexal squamous cell carcinomas (SCC). Methods: Forty-three samples of histologically confirmed cases of ocular SCC or carcinoma in situ (CIS) from 34 horses presented to the Animal Health Trust between 1992 and 2004 were subjected to a standard, two-layered, indirect immunohistochemical method using a rabbit polyclonal antihuman COX-2 antibody. Ten formalin-fixed, paraffin-embedded tissue samples taken from recognized predilection sites for SCC, from the grossly normal eyes of 10 horses euthanized for reasons unrelated to this study, were used as negative controls. Samples of equine fetal kidney were used as positive controls. Following immunolabeling, the number of normal and neoplastic epithelial cells exhibiting positive COX-2 expression was recorded along with staining intensity and distribution. Results: Of 43 tumors, 34 were defined as first presentation tumors. When compared with control tissue, in which 0% (0/10) of samples expressed COX-2, significantly more of these samples with SCC (58.6%, 17/29: P = 0.002), CIS (60%, 3/5: P = 0.022) or either tumor type (58.8%, 20/34: P = 0.001) exhibited positive cytoplasmic and perinuclear immunohistochemical staining for COX-2. Of the samples exhibiting positive immunohistochemical staining, only 10% (2/20) showed staining in 2%-10% of neoplastic cells, while 90% (18/20) showed staining in 1% of neoplastic cells. About 70% (14/20) of those positively immunolabeled samples exhibited an intensity of staining greater than or equal to the staining exhibited by the equine fetal kidney positive control. Conclusions: Neoplastic tissue from both equine ocular SCC and CIS exhibit COX-2 expression at significantly higher levels than normal control ocular tissue. However, the percentage of cells expressing positive immunohistochemical staining is consistently low. On the basis of this study, it is unlikely that anti-COX-2 therapy would be of benefit in the treatment of equine ocular and adnexal SCC.
Publication Date: 2008-12-17 PubMed ID: 19046264DOI: 10.1111/j.1463-5224.2008.00623.xGoogle Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
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This research study investigated the expression of cyclooxygenase-2 (COX-2) in equine ocular and adnexal squamous cell carcinomas (SCC). Results showed that SCC and carcinoma in situ (CIS) tissue exhibit COX-2 expression at significantly higher levels compared to normal control tissue. However, the proportion of cells showing positive staining for COX-2 was consistently low, indicating that anti-COX-2 therapy might not be beneficial in treating these equine cancers.
Objective of the Research
- The purpose of this research was to determine whether Cyclooxygenase-2 (COX-2), an enzyme involved in inflammation and in cancer cell proliferation, is expressed in equine ocular and adnexal squamous cell carcinomas — a common type of cancer in horses.
Methodology
- A total of 43 samples of histologically confirmed cases of ocular SCC or carcinoma in situ (CIS) from 34 horses were studied.
- The standard double-layer indirect immunohistochemical method was used using a rabbit polyclonal antihuman COX-2 antibody which reacts with the COX-2 in the tissue samples.
- Tissue samples from grossly normal eyes of 10 horses euthanized for unrelated reasons served as negative controls, while samples of equine fetal kidney were used as positive controls.
- After immunolabeling, the number of normal and neoplastic epithelial cells showing positive COX-2 expression was recorded along with the intensity and distribution of staining.
Results
- 58.6% of SCC samples, 60% of CIS samples, and 58.8% of either tumor type showed positive cytoplasmic and perinuclear staining for COX-2, which was significantly higher than the 0% expressing COX-2 in control tissue.
- However, in samples showing positive immunohistochemical staining, only a small percentage of neoplastic cells showed COX-2 expression.
- About 70% of those positively immunolabeled samples exhibited an intensity of staining similar or greater than the staining exhibited by the equine fetal kidney positive control.
Conclusion
- SCC and CIS tissue in horses show significantly higher levels of COX-2 expression than normal control tissue.
- However, the proportion of cells showing positive staining for COX-2 is consistently low, indicating that a great majority of the cells do not express the enzyme.
- Based on this study’s results, anti-COX-2 therapy might not be beneficial in treating these equine cancers due to the small percentage of cells expressing COX-2.
Cite This Article
APA
Smith KM, Scase TJ, Miller JL, Donaldson D, Sansom J.
(2008).
Expression of cyclooxygenase-2 by equine ocular and adnexal squamous cell carcinomas.
Vet Ophthalmol, 11 Suppl 1, 8-14.
https://doi.org/10.1111/j.1463-5224.2008.00623.x Publication
Researcher Affiliations
- Davies Veterinary Specialists, Manor Farm Business Park, Higham Gobion, Hertfordshire, UK. kms@vetspecialists.co.uk
MeSH Terms
- Animals
- Carcinoma in Situ / enzymology
- Carcinoma in Situ / veterinary
- Carcinoma, Squamous Cell / enzymology
- Carcinoma, Squamous Cell / veterinary
- Case-Control Studies
- Cyclooxygenase 2 / genetics
- Cyclooxygenase 2 / metabolism
- Eye Neoplasms / enzymology
- Eye Neoplasms / veterinary
- Female
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Neoplastic
- Horse Diseases / enzymology
- Horses
- Immunohistochemistry / veterinary
- Male
Citations
This article has been cited 3 times.- Crausaz M, Launois T, Smith-Fleming K, McCoy AM, Knickelbein KE, Bellone RR. DDB2 Genetic Risk Factor for Ocular Squamous Cell Carcinoma Identified in Three Additional Horse Breeds. Genes (Basel) 2020 Dec 5;11(12).
- Wojtkowska A, Małek A, Giziński S, Sapierzyński R, Rodo A, Sokołowska J, Zabielska-Koczywąs KA, Wojtalewicz A, Walewska M, Kautz E, Ostrzeszewicz M, Lechowski R. Comparison of MMP-2, MMP-9, COX-2, and PGP Expression in Feline Injection-Site and Feline Noninjection-Site Sarcomas-Pilot Study. Animals (Basel) 2024 Jul 19;14(14).
- Pimenta J, Prada J, Pires I, Cotovio M. Cyclooxygenase-2 (COX-2) Expression in Equine Melanocytic Tumors. Vet Sci 2024 Feb 7;11(2).
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