Avaliação da expressão da proteína EZH2 em carcinoma adenoide cístico e adenoma pleomórfico

Abstract

Salivary gland neoplasms present different behaviors, which do not follow the classic patterns of benign and malignant neoplasms. The rarity of some of these lesions makes it even more difficult to understand the mechanisms involved in the etiopathogenesis. Molecular markers such as the EZH2 protein have been used to investigate epigenetic changes in different neoplasms, helping to define the diagnosis and prognosis of the lesions. The aim of the study was to evaluate the expression of the EZH2 protein and to describe the clinical and microscopic characteristics of adenoid cystic carcinoma (ACC) and pleomorphic adenoma (PA) which emphasizes the importance of defining the malignancy of the neoplasm. Histopathological analysis of PA cases showed myoepithelial and glandular epithelial cells arranged as duct-like structures and sheets intermingled in the variable stroma and ACC cases showed the three growth patterns, tubular, cribriform and solid forms. All ACC and PA cases were positive for EZH2, with diffuse nuclear staining in neoplastic cells. The ACC samples showed significantly higher EZH2 expression compared to the PA. The covariables nodal metastasis, recurrence, growth pattern, presence of solid areas and perineural invasion have been described in relation to EZH2 staining in ACC samples. The results of the study improve the understanding of the clinical and histological characteristics of ACC, as well as on the behavior of lesions. In addition, the analysis showed that EZH2 is a potential marker of malignancy and highlights the importance of validating molecular markers of epigenetic alterations.