PD-L1 expression in canine cutaneous mast cell tumors

• Grant number: 18/08896-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2018
• End date: January 31, 2020
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Pathology
• Principal Investigator: Ricardo de Francisco Strefezzi
• Grantee: Bruna Eugenio Bispo
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil

Abstract

Mast cell tumor is one of the most common diagnosed tumors in Small Animal Practice, and it is more frequent in dogs than in cats. It is characterized by the abnormal proliferation of neoplastic mast cells. Although its etiology remains unknown, brachycephalic breeds such as Boxer and Boston terrier are more prone to develop this neoplasm, as well as individuals between seven and nine years old. Definitive diagnosis is made based on cytology or histopathology, along with clinical signs. Nevertheless, due to highly variable macroscopic features and biologic behavior, the treatment choice for each case is considered difficult. Therefore, new prognostic indicators for mast cell tumors are needed. The expression of PD-L1 in cancer cells have been successfully used as a tool to predict tumoral biologic behavior in human melanomas and lung carcinoma cases. Moreover, it is an important step to understand the mechanisms of cancer development and progression. This protein is responsible, beyond other functions, for the inhibition of cytotoxic T lymphocytes, one of the major mechanisms of elimination of mutated cells. The purpose of the present project is to verify PD-L1 expression in canine cutaneous mast cell tumors. Fifty cases will be evaluated through immunohistochemistry and the expression of the protein will be compared with histopathological grades, disease-related mortality and post-surgical survival. (AU)