A Subset of Equine Gastric Squamous Cell Carcinomas Is Associated With Equus Caballus Papillomavirus-2 Infection.
Authors: Alloway Elizabeth, Linder Keith, May Susan, Rose Trevor, DeLay Josepha, Bender Susan, Tucker Alison, Luff Jennifer
Journal: Veterinary pathology
Summary
Squamous cell carcinoma remains the most frequently diagnosed gastric tumour in horses, yet the biological mechanisms driving malignant transformation have remained largely unexplained until now. Alloway and colleagues investigated whether Equus caballus papillomavirus-2 (EcPV-2)—already implicated in equine genital squamous cell carcinomas—might similarly contribute to gastric SCC development, using PCR and in situ hybridization to detect viral oncogenes (E6/E7) in tumour tissue from 11 affected horses and control gastric samples from 15 unaffected animals. PCR detected EcPV-2 in 7 of 11 gastric SCCs (64%), with all control samples testing negative, whilst in situ hybridisation confirmed active viral nucleic acid within tumour cells in 5 of 11 cases (45%), including in metastatic lesions. For practitioners, these findings suggest that a significant proportion of equine gastric SCCs may have an infectious aetiology, potentially opening avenues for novel preventive or therapeutic interventions, though further investigation is needed to establish causation and determine whether viral screening might inform prognosis or management decisions in affected horses.
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Practical Takeaways
- •Equine gastric squamous cell carcinoma may have a viral component in some cases; screening for EcPV-2 could help identify at-risk horses and guide treatment decisions
- •The presence of EcPV-2 in nearly two-thirds of gastric SCCs suggests papillomavirus infection warrants investigation as a risk factor in horses with chronic gastric disease
- •Future research should explore whether EcPV-2 vaccination or antiviral strategies might prevent or slow progression of virus-associated gastric cancers
Key Findings
- •PCR detected EcPV-2 in 64% (7/11) of gastric squamous cell carcinomas versus 0% of control non-SCC gastric samples
- •In situ hybridization confirmed EcPV-2 E6/E7 oncogene expression in 45% (5/11) of gastric SCCs including metastatic lesions
- •EcPV-2 is associated with a subset of equine gastric squamous cell carcinomas, suggesting a potential viral etiology for this malignancy