Aim: We investigated the immunohistochemical expression of estrogen receptors alpha (ERalpha) and beta (ERbeta) in pituitary adenoma subtypes combined with clinicopathological factors.
Materials and methods: Pituitary adenomas (n=75) were immunostained for ERalpha and ERbeta using the streptavidin-biotin-peroxidase complex method with a monoclonal ERalpha antibody and polyclonal ERbeta antibody.
Results: Nuclear immunoreactivity for both receptors was highest among PRL, FSH/LH, null cell, and GH adenomas. ACTH, silent subtypes I and II corticotrophs, and subtype III adenomas were the least immunoreactive for both receptors. ACTH adenomas expressed significantly less ERalpha than FSH-LH, GH, and null cell adenomas. A significantly elevated ERalpha expression was observed in macroadenomas compared to microadenomas and non-invasive compared to invasive tumors.
Conclusion: ERalpha and ERbeta are differentially expressed in the various pituitary adenoma subtypes suggesting a cell-specific function for these receptors. To elucidate the role of ERalpha in tumor size and invasiveness, additional studies are required.