Authors: Greenwood Sarah, Chow-Lockerbie Betty, Epp Tasha, Knight Cameron, Wachoski-Dark Garrett, MacDonald-Dickinson Valerie, Wobeser Bruce
Journal: Veterinary pathology
Summary
# Editorial Summary: EcPV-2 and Equine Squamous Cell Carcinoma Equine papillomavirus type-2 (EcPV-2) has been implicated in genital squamous cell carcinoma (SCC) development, yet its prognostic significance remains unclear. Researchers in Western Canada used PCR assays, in situ hybridisation, and sequencing to detect EcPV-2 in 115 archived tissue samples spanning 6 years, correlating viral status with clinical outcomes and survival data gathered via retrospective veterinary survey. EcPV-2 was present in 29% of genital SCCs but notably absent from non-genital tumours, supporting a tissue-specific association; however, viral status bore no relationship to overall survival (P = 0.76). Treatment status and post-operative recurrence emerged as the strongest predictors of survival outcome, with untreated cases and those with recurrent disease showing significantly poorer prognosis (P < 0.01), whilst histological grade and surgical margin completeness did not influence survival. For equine practitioners managing genital SCCs, these findings suggest that whilst EcPV-2 may facilitate tumour initiation in genital tissues, aggressive surgical intervention and prevention of recurrence should remain the primary focus rather than viral testing; conversely, horses left untreated face substantially worse outcomes regardless of viral status.
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Practical Takeaways
- •EcPV-2 detection does not influence prognosis or survival outcomes in equine SCCs, so treatment decisions should not be based on viral status alone
- •Treatment is critical — horses left untreated have significantly worse outcomes than treated cases, making early intervention a priority regardless of papillomavirus status
- •Post-treatment recurrence is a major prognostic concern; ensure complete surgical margins and monitor closely for relapse as these directly impact survival
Key Findings
- •EcPV-2 DNA was detected in 17% of SCCs, 30% of papillomas, but 0% of carcinomas in situ across 115 archived tissue samples
- •EcPV-2 was present in 29% of genital SCCs but 0% of SCCs from non-genital locations
- •EcPV-2 status was not associated with overall survival in equine SCCs (P = 0.76)
- •Lack of treatment and post-treatment recurrence were the strongest negative predictors of survival (P < 0.01)