RESUMO
PLAG1 (pleomorphic adenoma gene 1) is frequently activated in pleomorphic adenoma (PA). Carcinoma ex pleomorphic adenoma (CXPA) arises in PA, and PLAG1 expression is believed to be maintained from PA to CXPA, as it can contribute to the carcinogenesis process. To evaluate if PLAG1 is a good marker of malignant transformation from PA to CXPA as well as to evaluate if PLAG1 expression is associated with progression and histopathologic subtype of CXPA. Forty PAs, 21 residual PAs (without malignant transformation), and 40 CXPAs were analyzed by immunohistochemistry with PLAG1 antibody. The proportion of positive neoplastic cells was assessed according to a 2-tiered scale: >10% to 50%, and >50% positive cells. The CXPA group was classified according to histopathologic subtype and invasiveness degree. Thirty-seven PAs (92.5%), 15 residual PAs (71%), and 14 CXPAs (35%) were positive for PLAG1. In relation to the CXPA group, among the intracapsular cases, myoepithelial carcinoma and epithelial-myoepithelial carcinoma showed the highest level of PLAG1 expression. PLAG1 expression is lost when PA undergoes malignant transformation, possibly due to other pathway activation and different clone cells. In addition, PLAG1 expression seems to be present mainly in low-grade carcinomas and in cases with early phase of invasion, due to its regulation of oncogene-induced cell senescence. In CXPA, PLAG1 expression was most associated with myoepithelial differentiation. This way, loss of PLAG1 expression can be considered a hallmark of CXPA carcinogenesis, mainly when there is only epithelial differentiation.
Assuntos
Adenoma Pleomorfo/química , Biomarcadores Tumorais/análise , Carcinoma/química , Transformação Celular Neoplásica/química , Proteínas de Ligação a DNA/análise , Neoplasias das Glândulas Salivares/química , Adenoma Pleomorfo/patologia , Carcinoma/patologia , Estudos de Casos e Controles , Diferenciação Celular , Transformação Celular Neoplásica/patologia , Progressão da Doença , Regulação para Baixo , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Invasividade Neoplásica , Neoplasias das Glândulas Salivares/patologiaRESUMO
The aim of this study was to determine the range of oral histopathological diagnoses in a Brazilian survey obtained from a surgical pathology hospital laboratory. Materials and Methods: A retrospective cross-sectional study was performed, and all histological slides from the oral and maxillofacial region during a 14-year period were reviewed. The diagnoses were grouped intofive major diagnostic categories, and age and sex were specified. Results: A total of 769 samples were collected and submitted for histopathological analysis. There were 245 oral cases, which were divided into 48 different diagnoses. There was no sex predilection, and the mean age was about 44 year sold. Proliferative non-neoplastic lesions (43.2%) and malignant neoplasms (26.5%) comprised the main two groups of diagnoses. Conclusion: The malignant neoplasms prevalence observed in this Brazilian sample may be due to the nature of the populationor, most probably, to the nature of the source, are ferral hospital center in the city...
O objetivo deste estudo foi determinar avariação de diagnósticos histopatológicos da cavidade oral em uma amostra brasileira obtida a partir de um laboratório hospitalar de patologia cirúrgica. Material e Métodos: Um estudo transversal retrospectivo foi realizado e todas as lâminas histopatológicas da região oral e maxilofacial durante um período de 14 anos foram revisadas. Os diagnósticos foram agrupados em cinco categorias principais de diagnóstico, sendo o sexo e a idade especificados. Resultados: Um total de 769 amostras foram coletadas e submetidas a análise histopatológica. Foram identificados 245 casos de lesões orais, que foram subdivididas em 48 diferentes diagnósticos. Não houve predileção por sexo, e idade média foi de 44 anos. Lesões proliferativas não-neoplásicas (43,2%) e neoplasias malignas (26,5%) representaram os dois principais grupos de diagnóstico. Conclusão: A prevalência de neoplasias malignas observada nesta amostra brasileira pode ser explicada devido a natureza da população ou, mais provavelmente, pela natureza da fonte, um hospital de referência na cidade...