Análise da transição epitelial-mesenquimal sob o comportamento metastático e caráter prognóstico em melanomas caninos

Abstract

Melanocytic tumors represent about 7% of malignant neoplasms in dogs and have a poor prognosis due to the high incidence of metastasis, mainly affecting the oral cavity, skin, and mucocutaneous regions. Various studies demonstrate that the progression of melanomas may be related to changes in cell adhesion, especially in the process of epithelial-mesenchymal transition (EMT); however, its direct relationship with metastatic formation and animal survival remains uncertain. Thus, the present study evaluated the expression of the proteins E-cadherin and N-cadherin, involved in EMT, in canine melanomas and their metastatic lymph nodes, and the relationship of this expression with the survival time of the animals. Thirty-two cases of canine melanomas and their respective lymph nodes were selected. A histopathological evaluation was performed for tumor characterization, and the immunohistochemistry was applied for Melan-A, PNL-2, E-cadherin, and N-cadherin, both in primary tumors and in lymphatic metastases. Among the cases analyzed, 47% were non-metastatic, and 53% were metastatic, with high E-cadherin expression in both groups. In contrast, N-cadherin showed significant variation between groups, with higher expression in metastatic tumors. Tumors with high E-cadherin and N-cadherin expression were associated with histological features of tumor aggressiveness and poorer animal prognosis. The data obtained support the hypothesis of a potential role for EMT in canine melanoma progression.