Cyclooxygenase-2 expression in animal cancers.
Authors: Doré M
Journal: Veterinary pathology
Summary
# Editorial Summary: Cyclooxygenase-2 in Animal Cancers Cyclooxygenase-2 (COX-2), an inducible enzyme central to prostaglandin synthesis, has long been implicated in human cancer development through its production of PGE₂, which suppresses apoptosis, accelerates cell proliferation, promotes angiogenesis, and impairs immune responses. This comprehensive review examines COX-2 expression across cancers in dogs, cats, and horses, synthesising evidence for its role in veterinary oncology. Elevated COX-2 expression appears widespread in animal malignancies, though current evidence remains insufficient to establish clear prognostic value, with only limited reports (notably in canine mammary tumours and osteosarcomas) documenting associations between COX-2 levels and survival outcomes. Non-steroidal anti-inflammatory drugs show the most promising therapeutic potential in canine urinary transitional cell carcinoma, yet measuring tumour COX-2 expression alone does not reliably predict treatment response or prognosis. For equine, canine, and feline practitioners, this highlights both the theoretical merit of COX-2-targeted strategies and the current research gaps; whilst COX inhibitors warrant further investigation, measuring COX-2 expression cannot presently guide clinical decision-making, and substantially more work—including development of relevant in vitro models—is needed before COX-2 becomes a reliable prognostic biomarker or definitive therapeutic target.
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Practical Takeaways
- •While COX-2 involvement in cancer development is documented, measuring COX-2 levels in tumors is not currently useful for predicting prognosis or treatment response in clinical practice
- •NSAIDs may have preventive or therapeutic potential for certain cancers (especially transitional cell carcinomas in dogs), but further research is needed before clinical recommendations can be made
- •Cancer management decisions should not be based on COX-2 expression testing alone; additional diagnostic and prognostic factors remain essential
Key Findings
- •COX-2 upregulation is present in many animal cancers, but prognostic significance remains unclear
- •Limited evidence of COX-2 expression correlation with survival in canine mammary cancers and osteosarcomas
- •COX inhibitors show potential in prevention/treatment of certain cancers, particularly canine urinary transitional cell carcinomas
- •COX-2 tumor levels are not reliable prognostic factors or predictors of NSAID therapy response