Immunohistochemical detection of FSH receptors in pituitary adenomas and adrenal tumors
Folia Histochemica et Cytobiologica
Follicle stimulating hormone (FSH) receptors (FSHR) are physiologically expressed in the ovary and testis. It is well known that FSHR are also expressed in gonadal cancers, but data regarding their incidence in extra-gonadal tumors is scarce. Recently, the expression of FSHR in the vascular endothelium within different human cancers was found, but nothing is yet known about FSHR appearance in non-gonadal endocrine tumors. The present paper reports on the immunohistochemical detection of FSHR in
... etection of FSHR in human pituitary adenomas and adrenal tumors. The study included samples of 28 pituitary adenomas and 37 adrenal tumors. Moreover, two samples of non-tumoral adrenal glands were also studied. FSH receptor immunostaining was performed on paraffin sections using the rabbit anti-human FSH-R polyclonal antibody raised against 1-190 amino acid sequence from the human FSH-R (sc-13935). The pituitary adenomas were immunostained to reveal the pituitary hormones and the proliferation marker Ki-67. In the pituitary adenomas, positive immunostaining with anti-FSHR antibody occurred in the adenoma cells cytoplasm and endothelia of the intra-and peritumoral blood vessels. Cytoplasmic immunostaining was found in the majority of investigated tumors, but the intensity of staining was weak to moderate. There was some tendency towards a higher cytoplasmic FSHR score in tumors with higher Ki-67 index (atypical adenomas). In contrast to the cytoplasm, the FSHR immunostaining in blood vessels was strong and concerned all the investigated samples. Strong FSHR immunostaining was present in the endothelium of intra-and/or peritumoral blood vessels in the majority of pheochromocytomas, approximately one half of the adrenocortical adenomas, and all cases of adrenal cancers. The immunostaining was detectable also in the tumoral cell cytoplasm in all but one examined pheochromocytomas. All the investigated adrenocortical adenomas presented strong immunostaining of cell membranes. No immunostained cell membranes were found in adrenal cancers. The positive immunostaining was found in glandular cells, but not in blood vessels of non-tumoral adrenal cortex and medulla. Immunostaining of FSHR often occurs in the endothelium of intra-and/or peritumoral blood vessels of pituitary adenomas and benign and malignant adrenal tumors. The immunostaining may be also present in neoplastic cells. A role of FSHR expression in these tumors, such as stimulation of angiogenesis or of cell proliferation, needs to be clarified in further studies.