High P53 Immunoexpression Is Associated With Shorter Overall Survival in Feline Cutaneous Squamous Cell Carcinoma

Background/Aim: Cutaneous squamous cell carcinoma (cSCC) is a common skin tumor in cats, typically arising in sun-exposed, poorly pigmented areas. Ultraviolet radiation induces carcinogenesis through DNA damage in keratinocytes, with p53 dysregulation as an early and frequent event. Although its prognostic value remains controversial, p53 overexpression has been associated with poorer outcomes in human cSCC, with limited data in cats. This study evaluated p53 immunoexpression and its association with clinicopathological features and survival in cats with cSCC treated with electrochemotherapy (ECT). Patients and Methods: A total of 33 cats with head cSCC were included from both prospective (2022-2025) and retrospective (2018-2021) cohorts. Tumor samples were collected immediately before the first ECT session for histopathological and subsequent immunohistochemical analysis. Results: Nuclear p53 immunoexpression was detected in 84.8% of cases (28/33), classified as moderate (18/33; 54.5%) and high (10/33; 30.3%). High p53 immunoexpression was significantly associated with shorter tumor-specific survival (TSS) (p=0.026) and overall survival (OS) (p=0.01). Advanced-stage tumors (T3 and T4) were significantly associated with moderate to high p53 immunoexpression (p=0.028). Conclusion: These findings suggest that p53 immunoexpression may serve as a prognostic biomarker in feline cSCC, supporting its potential clinical applicability in the prognostic assessment of affected cats.