Immunohistochemical Expression of Tyrosine Kinase Receptors EGFR and CD117 in Canine Urothelial Carcinoma

Canine urothelial carcinoma is the most common malignant neoplasm of the lower urinary tract in dogs and is characterized by aggressive biological behavior, high invasiveness, and metastatic potential. Despite advances in our understanding of this neoplasm, few molecular biomarkers with diagnostic, prognostic, and therapeutic value have been identified. In this context, the present study aimed to evaluate the immunohistochemical expression of the tyrosine kinase receptors EGFR (Epidermal Growth Factor Receptor) and CD117 (c-KIT) in canine urothelial carcinomas. EGFR and CD117 were positive in the majority of cases; both were individually associated with a high histologic grade. In multivariate analysis, a high histological grade was independently associated with EGFR, whereas CD117 was not. In a separate model, EGFR/CD117 co-expression was also independently associated with high histological grade. EGFR and CD117 expression were themselves significantly associated, with 95.0% of EGFR-positive tumors also CD117-positive, a pattern that warrants further investigation into a potential interplay between these pathways during urothelial carcinogenesis. To our knowledge, this is the first study to simultaneously assess EGFR and CD117 in canine urothelial carcinoma; these findings support further investigation into their potential as combined therapeutic targets and suggest that the canine model may offer valuable insights for human precision oncology.