Epithelial–mesenchymal transition in an EcPV2‐positive vulvar squamous cell carcinoma of a mare

BackgroundVulvar squamous cell carcinoma (VSCC) has been recently associated with Equus caballus papillomavirus type 2 (EcPV2) infection. Still, few reports concerning this disease are present in the literature. ObjectiveTo describe a case of naturally occurring EcPV2-induced VSCC, by investigating tumour ability in undergoing the epithelial-to-mesenchymal transition (EMT). Study designCase report. MethodsA 13-year-old Haflinger mare was referred for a rapidly growing vulvar mass. After surgical excision, the mass was submitted to histopathology and molecular analysis. Histopathological diagnosis was consistent with a VSCC. Real-time qPCR, real-time reverse transcriptase (RT)-qPCR and RNAscope were carried out to detect EcPV2 infection and to evaluate E6/E7 oncogenes expression. To highlight the EMT, immunohistochemistry (IHC) was performed. Expression of EMT-related and innate immunity-related genes was investigated through RT-qPCR. ResultsReal-time qPCR, RT-qPCR and RNAscope confirmed EcPV2 DNA presence and expression of EcPV2 oncoproteins (E6 and E7) within the neoplastic vulvar lesion. IHC highlighted a cadherin switch together with the expression of the EMT-related transcription factor HIF1 & alpha;. With RT-qPCR, significantly increased gene expression of EBI3 (45.0 & PLUSMN; 1.62, p < 0.01), CDH2 (2445.3 & PLUSMN; 0.39, p < 0.001), CXCL8 (288.7 & PLUSMN; 0.40, p < 0.001) and decreased gene expression of CDH1 (0.3 & PLUSMN; 0.57, p < 0.05), IL12A (0.04 & PLUSMN; 1.06, p < 0.01) and IL17 (0.2 & PLUSMN; 0.64, p < 0.05) were detected. Main limitationsLack of ability to generalise and danger of over-interpretation. ConclusionThe results obtained were suggestive of an EMT event occurring within the neoplastic lesion.