Vimentin expression in canine testicular tumors: a local invasion predictive biomarker

Testicular neoplasms have high incidence in dogs and, despite curative surgical treatment, reported cases have shown aggressive behavior and metastatic dissemination in malignant versions of these tumors. Vimentin is a cytoplasmic protein characteristic of mesenchymal cells, but recently implicated in epithelial-mesenchymal cell transition. This reprogramming cellular event increases tumoral cell invasiveness and metastatic dissemination. Concerning such important oncological implications, vimentin immunohistochemical expression was analyzed in the three most frequent testicular tumors in dogs, as a predictor of local invasiveness. Sixty-eight samples retrieved from a pathological anatomy laboratory were evaluated and their histopathological diagnosis established. Immunohistochemical process followed lab protocol for anti-vimentin antibody. Immunolabeling was analyzed according to intensity criteria: absent, weak, moderate, or intense. In this case series, 39.7% were Leydig cell tumors, 33.8% were seminomas, and 26.4% were Sertoli cell tumors; the last two were further classified as intratubular or diffuse, according to seminiferous tubule location. Vimentin immunolabeling was observed in all three tumor types. Leydig cell tumors showed intense immunolabeling in samples totality, clearly differentiating tumoral from normal cells. Sertoli cell tumors presented marked immunolabeling but also did normal Sertoli cells. Seminoma vimentin-immunolabeling was variable. Diffuse Sertoli cell tumor and seminoma presented more intense vimentin immunolabeling when compared to intratubular counterparts, suggesting this protein role in expansive tumoral behavior and seminiferous tubule rupture. Vimentin overexpression in canine testicular tumors can contribute to tumoral local invasion and consequently impairment of the remaining normal testicular tissue in affected dogs.