Evaluation of tumor-associated neutrophils (TAN) and their relationship in the tumor microenvironment: study in canine oral melanoma

• Grant number: 22/00528-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2022
• End date: March 31, 2023
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Pathology
• Principal Investigator: Cristina de Oliveira Massoco Salles Gomes
• Grantee: Matheus Canela dos Santos
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Neutrophils are a cell population known mainly for their important participation as phagocytes in infectious, inflammatory, and healing processes. In the cancer scenario, a new perspective about the action of this cell type has emerged, since the traditional idea that neutrophils are inert agents is being revisited. Evidence indicates that tumors can recruit neutrophils through the secretion of a series of stromal-derived chemoattractants and, once, inside the tumor microenvironment, neutrophils can be exposed to different phenotypic and functional polarization states capable of altering the behavior of the tumor. About the canine oral melanoma, a neoplasm of difficult therapeutic control for the veterinary oncologist, there is no relevant information on the frequency of neutrophilic infiltrate outside the areas of necrosis nor on the relation between the profile of this infiltrate and the anatomopathological characteristics or clinical staging. This present work is a retrospective study whose objective is to analyze the profile and frequency of intra and peri-tumoral neutrophilic infiltrate (outside the necrosis area) in samples of canine oral melanoma in different clinical stages, and also investigate the relation between the type of infiltrating with the following factors: the cell proliferation rate, the microvascular density and the anatomical and histopathological characteristics of the tumor (histological type, necrosis, vascular and lymphatic invasion, ulceration, inflammatory infiltrate, junctional activity and nuclear atypia), the presence of metastases, the disease-free time and overall patient survival. 100 samples of canine oral melanoma will be used, from which slides will be prepared for histopathological analysis in hematoxylin and eosin. From these slides, the evaluation of the histological variables will be carried out in light microscopy, and there will be a subsequent performance of immunohistochemistry for analysis of angiogenesis. The data obtained from the present study may favor the development of new clinical research and therapies, which may help veterinary and human medicine in the fight against melanocytic neoplasms.(AU)