Introduction: The expression of estrogen receptors in salivary gland tissue has been observed in some studies. Considering the histological similarity of salivary gland and breast tissue, as well as the prominent role of this receptor in the pathogenesis, treatment and prognosis of breast tumors, the aim of this study was to compare the immunohistochemical expression of estrogen receptor in pleomorphic adenoma (PA) and normal salivary gland tissue and assess its possible role in salivary gland tumors.
Materials and Methods: In this descriptive-analytical study, 26 samples of PA and 12 samples of normal salivary gland tissue were selected. Immunohistochemical staining was performed by standard invision method for estrogen receptor. The results were evaluated semi-quantitively as the percentage of nuclear and cytoplasmic stained cells separately by Mann- Whitney, Kruskal-Wallis and Fisher exact tests.
Results: All PA samples showed negative nuclear staining for estrogen receptor, but its expression was observed in the cytoplasm of ducts in 27% of tumors and in 59% of normal salivary gland tissue samples, but the difference was not statistically significant. In addition, no association was found between estrogen receptor expression and independent variables such as the type of stroma or the degree of cellularity in PA, age, sex and location of the specimen.
Conclusion: It seems that the expression of estrogen receptor does not play an effective role in the development and progression of PA tumor. However, its occurrence in the normal salivary gland ducts is considered and further studies in this field seem to be necessary.