Análise da imunoexpressão de OCT4 e CD44 em neoplasias de glândulas salivares menores e maiores / Immunohistochemical analysis of OCT4 and CD44 in minor salivary gland neoplasms and higher

RESUMO

As neoplasias de glândulas salivares exibem uma ampla variedade de comportamento biológico e grande diversidade morfológica, e esta heterogeneidade inerente a este grupo de tumores suscita o interesse em pesquisar estas lesões. As células-tronco são a principal fonte para a geração e manutenção da diversidade celular e homeostase do tecido, distúrbios na regulação destas células podem levar à produção de células-tronco alteradas, denominadas de células-tronco tumorais, que possuem potencial proliferativo e capazes de originar e/ou manter o tumor. Pesquisas acerca das células-tronco tumorais e das proteínas a elas associadas em algumas neoplasias orais têm sido desenvolvidas, no entanto, o papel destas em neoplasias de glândulas salivares não está ainda bem estabelecido. Desta forma, o objetivo deste estudo foi identificar células do parênquima tumoral que expressam marcadores de células-tronco tumorais, através da avaliação da imunoexpressão do OCT4 e CD44, em uma série de casos de neoplasias de glândulas salivares. A amostra foi constituída por 20 adenomas pleomórficos, 20 carcinomas mucoepidermóides e 20 carcinomas adenóides císticos localizados nas glândulas salivares menores e maiores.

ABSTRACT

Salivary gland neoplasms exhibit a wide variety of biological behavior and a high morphological diversity raises the interest in researching these lesions. The stem cells are the main source for the generation and maintenance of cell diversity, disorders in the regulation of these cells can lead to the production of altered stem cells, termed cancer stem cells capable of generate the tumor. Researches on cancer stem cells and associated proteins have been developed in some oral cancers; however, their role in salivary gland neoplasms is not well established. Thus, the aim of this study was to identify the tumor parenchyma cells exhibiting stem cell characteristics, by evaluating the immunoreactivity of OCT4 and CD44, in a number of cases of salivary gland neoplasms. The sample consisted of 20 pleomorphic adenomas, 20 mucoepidermoid carcinomas and 20 adenoid cystic carcinoma located in minor and major salivary glands. The expression of OCT4 and CD44 was evaluated by the percentage of positive cells (PP) and the intensity of expression (IE), it is realized the sum of the scores, resulting in the total score immunostaining (PIT) ranging 0-7. All studied cases showed positive expression of OCT4 and CD44 and higher values than the control groups. It was observed that for OCT4 luminal cells and non-luminal were immunostained in the case of pleomorphic adenomas and adenoid cystic carcinoma. Already the immunoreactivity of CD44 was particularly evident in the non-luminal cells of these lesions. In mucoepidermoid carcinomas for both markers, there was immunoreactivity in squamous and intermediate cells and absence of staining mucous cells.