Estudo da expressão de B-Catenina e do KI-67 em neoplasias melanocíticas caninas

Abstract

This study, carried out at the Laboratory of Animal Pathology of the Faculty of Agronomy and Veterinary Medicine of the University of Passo Fundo, deals with the analysis of 26 canine melanocytic neoplasms through clinical-pathological and immunohistochemical evaluation, with the objective of ascertaining the marking pattern of the β-catenin molecule and if there is a correlation with the cellular proliferation evaluated by Ki-67 expression, as well as if there is a correlation of these markers with clinical-pathological factors. Canine melanocytic neoplasms originate from the proliferation of melanocytes and are called melanocytoma when benign, and melanoma when malignant. Melanona present poor prognosis, causing metastases in most animals. The precise diagnosis is obtained through the association of clinical-pathological factors with immunohistochemistry, a necessary tool to establish the prognosis and appropriate therapy. Immunohistochemical markers, such as Ki-67, are used to improve the prognostic quality of human and canine melanoma, since they allow the evaluation of the rate of cell proliferation. This work described data on the clinical-pathological parameters of benign and malignant primary melanocytic neoplasms: cutaneous and oral, melanocytic and amelanotic. The variables were: tumor location, macroscopic ulceration, age and gender of the animals, as well as the presence of necrosis and microscopic ulceration, nuclear atypia and mitotic index. As for the labeling site of β-catenin, it was verified whether cytoplasmic, nuclear or mixed. The clinical-pathological parameters that demonstrated significance were: the age of affected animals, microscopic ulceration and necrosis, nuclear atypia and mitotic index, all in relation to melanomas. There was no statistical difference between the β-catenin labeling sites between benign or malignant melanocytic neoplasms, as well as no correlation between the β-catenin molecule and the Ki-67 marker. To date, the relationship of β-catenin expression and Ki-67 expression to pre-established clinical-pathological prognostic factors has not been studied.