Endocrine differentiation of extra-pulmonary small cell carcinoma demonstrated by immunohistochemistry using antibodies to PGP 9.5, neuron-specific enolase and the C-flanking peptide of human pro-bombesin

Several recent studies have confirmed the endocrine nature of small cell carcinoma of the lung. In extra-pulmonary sites, small cell 'undifferentiated' carcinomas have classical morphological features similar to their pulmonary counterpart. We therefore investigated, using immunocytochemistry, the possibility that the non-pulmonary neoplasms may also be endocrine in nature. Sections of 29 small cell carcinomas from oesophagus, stomach, larynx, colon and urinary bladder were immunostained using antisera to protein gene product 9.5 (PGP 9.5), neuron-specific enolase (NSE), cytokeratin, leucocyte common antigen and peptides including bombesin, the C-flanking peptide of human probombesin, adrenocorticotrophic hormone, neurotensin, calcitonin and pancreatic polypeptide. All the tumours showed immunoreactivity for at least one of the two general endocrine markers PGP 9.5 and NSE. Twenty-three of the 29 cases were immunoreactive for PGP 9.5, 27 for NSE. All were positive for cytokeratin and negative for leucocyte common antigen. Of the regulatory peptides, immunoreactivity was obtained with antisera to bombesin (one case), the C-flanking peptide of human pro-bombesin (14 cases), adrenocorticotrophic hormone (one case) and calcitonin (three cases). No PGP 9.5-, NSE- or peptide-like immunoreactivity was detected in 25 control tumours from similar sites, including lymphomas and poorly differentiated tumours. These results suggest that non-pulmonary small cell carcinoma has an endocrine character.     

Immunohistochemical distribution of regulatory peptides in the human fetal adenohypophysis

We have studied here the cellular distribution of several regulatory peptides in hormone-producing cells of the human pituitary during the fetal period. Immunohistochemistry was used to show the expression of several regulatory peptides, namely Angiotensin-II, Neurotensin and Galanin, at successive gestational stages and their co-localization with hormones in the human fetal adenohypophysis. Somatotrophs, gonadotrophs and thyrotrophs were differentiated earliest. At gestational week 9, Angiotensin-II immunoreactivity was co-localized only with growth hormone immunoreactivity in somatotrophs, one of the first hormone-producing cells to differentiate. This co-localization remained until week 37. Neurotensin immunoreactivity was present in gonadotrophs and thyrotrophs in week 23, after FSH and TSH hormone differentiation. Galanin immunoreactivity was present in all hormone-producing cell types except corticotrophs. The different pro-opiomelanocortin-derived peptides were detected at different stages of gestation and adrenocorticotrophic hormone immunoreaction was the last to be detected. Our results show an interesting relationship between regulatory peptides and hormones during human fetal development, which could imply that these peptides play a regulatory role in the development of pituitary function.     

A study of different markers for neuroendocrine differentiation in breast carcinomas

Forty-two breast carcinomas were studied with different markers for detecting neuroendocrine differentiation. The Bodian and Grimelius silver stains were applied, as well as immunostaining for neurone specific enolase (NSE), chromogranin, prealbumin and a battery of hormones. All cases were studied by electron microscopy as well. The material included 29 infiltrating ductal carcinomas, 10 infiltrating lobular carcinomas and 3 tubular carcinomas. Immunostaining for hormones was obtained in 11 cases (gastrin and PP (4 cases each), leu-enkephalin (3 cases), substance P (2 cases), beta-endorphin (2 cases), ACTH (1 case) and bombesin (1 case). Three cases revealed immunostaining for more than one hormone. Sixteen cases were positively stained with rabbit anti-NSE (Dako Corporation) and included all the 11 cases with proven immunoreactivity for hormones. 20 cases were positively stained with sheep anti-NSE and only 8 of the 11 cases with immunoreactivity for hormones were included. Immunostaining for prealbumin was observed in only 1 case and chromogranin in only 5 cases. All cases were unstained with the Bodian stain, whereas 3 cases showed a positive argyrophilic reaction with the Grimelius technique. Ultrastructural studies revealed typical small membrane-bound electron dense granules in cytoplasm in 4 cases, all among the 11 cases with immunoreactivity for hormones. We conclude that immunostaining with rabbit anti-NSE is the best screening method for detecting breast carcinomas with neuroendocrine differentiation.     

Intracranial tumours in budgerigars

In a retrospective study of 996 budgerigars 14 intracranial tumours were examined histologically and immunocytochemically. Tumours of the ependyma (6), choroid plexus (1), adenohypophysis (6) and one unclassified tumour were found. Immunostaining was applied using antibodies against glial fibrillary acidic protein, vimentin, cytokeratin, neuron specific enolase, neurofilament-200 and S-100 protein. The presence of hormones in pituitary tumours was also tested by immunocytochemistry with antibodies to adrenocorticotrophic hormone, melanocyte-stimulating hormone, prolactin and growth hormone. Positive immunostaining was found in two carcinomas of the adenohypophysis using anti-growth hormone antibody and, by using anti-S-100 antibody, in the cytoplasm of several cells of the remaining tumours. There was no immunoreactivity in either normal or neoplastic tissues of budgerigars with anti-glial fibrillary acidic protein, anti-vimentin, anti-cytokeratin and anti-neuron specific enolase antibodies. With anti-neurofilament-200 antibody, positive immunoreactivity was found in neuronal fibres of normal brain but not in neoplastic tissue.     

Immunohistochemical and Ultrastructural Analysis of Bronchopulmonary Neuroendocrine Neoplasms. I. Carcinoids

Twenty-five strictly defined bronchopulmonary carcinoids were studied by light microscopic immunohistochemistry by the peroxidase technique for NSE (neuronspecific enolase), serotonin, and a broad spectrum of neuropeptides. Eighteen cases were also studied by electron microscopy.

Twenty-three of the twenty-five cases showed immunostaining for NSE; 24 cases displayed immuno-staining for at least two of the hormones tested for; the single case that failed to show hormonal immuno-reactivity was however positive for NSE and had granules by electron microscopy. Serotonin was the most frequently demonstrated hormone followed by bombesin, vasoactive intestinal peptide, gastrin, leuenkephalin, alphamelanocyte stimulating hormone, somatostatin, substance P, and calcitonin. In several cases, adjacent-step sections stained for different hormones strongly indicated immunoreactivity for more than one hormone in single neoplastic cells.

By electron microscopy, all 18 cases studied showed generally abundant neurosecretory granules, which, however, displayed considerable heterogeneity in their size, shape, and density. Twelve of these eighteen cases displayed evidence of squamous differentiation and 10 showed characteristic exocrine lumina.

The capability of single neuroendocrine tumors and single neuroendocrine tumor cells to produce more than one immunoreactive hormone is hereby amply confirmed; these broad capabilities are certainly reflected in the heterogeneous granule populations seen by electron microscopy. The synchronous presence of squamous and exocrine features in bronchopulmonary carcinoids indicates that they too are capable of multidirectional differentiation, which should not detract from their being regarded basically as well-differentiated neuroendocrine neoplasms. The clinical significance of strictly defining bronchial carcinoids is underscored by the fact that of 25 cases followed for 2-13 years, only one developed metastases 9 years postoperatively.     

Comparative immunohistochemical analysis of estrogen receptor and chromogranin-A reactivity in plurihormonal human prolactinomas

The aim of the study was to compare the immunoreactivity of estrogen receptors (ER) and chromogranin-A (CHR-A) in human prolactinomas with verified plurihormonality. Eleven cases of prolactinomas, nine found in women aged from 15-32 and two found in two men both aged 54 years, were analyzed for possible colocalization of other hormones produced by adenohypophysis, i.e. growth hormone (GH), thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH) and adrenocorticotropic hormone (ACTH). All evaluated cases of prolactinomas were clinically manifested by elevated values of prolactin (PRL) in patient serum, while the values of other assayed hormones were within the normal range. Although biopsy material is not routinely submitted to immunohistochemical analysis for plurihormonality, these eleven cases of operated prolactinomas were randomly examined to the presence of plurihormonality. In six cases of prolactin-producing adenomas, the coexistence of growth hormone was detected. Colocalization of follicle-stimulating hormone and weak expression of adrenocorticotropic hormone were found in two cases each. Thus, bihormonal activity (PRL + GH) was found in six, and trihormonal activity (PRL + GH + FSH and PRL/GH + ACTH) in three cases of prolactinoma. In addition, the presence of prolactin and growth hormone was demonstrated in morphologically different cells. Eight of these eleven pituitary adenomas were tested for estrogen receptors (ER), which play an important role as growth stimulating factors and secretory factors for prolactin-producing cells. We tried to determine if there was a difference in the intensity of expression of estrogen receptors and chromogranin-A between pure prolactinomas and mixed, plurihormonal prolactinomas. By use of monoclonal antibodies, chromogranin-A found to be reactive in seven of eleven prolactinomas, i.e. in plurihormonal prolactinomas. Estrogen receptors were markedly expressed in all the eight prolactinomas analyzed, which may prove significant in the treatment of these hypophyseal tumors.     

Vasoactive intestinal peptide in the human pituitary gland and adenomas. An immunocytochemical study

Recent evidence indicates that vasoactive intestinal peptide (VIP) may be involved in normal pituitary function. Immunocytochemistry was used to localize VIP in human biopsied pituitary adenomas and postmortem anterior pituitary glands. Paraffin sections were immunostained for VIP with the avidin-biotin-peroxidase technique. Strong VIP-like immunoreactivity (VIP-LI) was observed in 16 of 17 prolactinomas, 12 of 14 growth hormone-secreting tumors associated with acromegaly, four of 12 ACTH-secreting tumors, and 14 of 18 nonfunctioning pituitary adenomas. In most cases, VIP was colocalized with the classical pituitary hormones. Six of the 18 nonfunctioning tumors had no demonstrable hormone immunoreactivity; five of these stained strongly for VIP, whereas one was negative. Of 18 normal anterior pituitaries, 12 showed strong diffuse staining for VIP throughout the gland. One pituitary with VIP-LI came from an individual who had undergone pituitary stalk transection. Double-immunoenzyme labeling and immunoelectron microscopy demonstrated VIP-LI in many lactotrophs, scattered thyrotrophs, corticotrophs, and in an occasional gonadotroph. These results suggest the following: 1) VIP is present in more than one cell type in normal and adenomatous human pituitaries; and 2) VIP may be involved in the function and development of pituitary tumors.     

Prognostic implications of epidermal growth factor receptor immunoreactivity in squamous cell carcinoma of the oral mucosa

To evaluate the clinical significance of the expression of epidermal growth factor receptor (EGFr) in oral squamous cell carcinoma (SCC), 100 formalin-fixed, paraffin-embedded cases of this tumour and ten samples of normal oral mucosa were immunostained with a monoclonal anti-EGFr antibody using an immunoalkaline phosphatase (APAAP) technique. EGFr immunoreactivity was detected in 36 of 100 tumours and in all samples of normal mucosa. Tumour cells demonstrated distinct membrane staining in 14 cases and predominantly cytoplasmic staining in 22 additional cases. EGFr was exclusively localized on the cell membrane of normal epithelial cells. Kaplan–Meyer survival curves and Cox proportional hazard regression models were used to assess overall survival and disease-free survival. A significant positive correlation was shown between EGFr membranous immunoreactivity and prolonged survival, in both univariate and multivariate analyses. Accordingly, patients with oral SCC showing down-regulated expression of membranous EGFr, who are more likely to suffer recurrence and death, should be strictly followed up and possibly treated with more aggressive therapeutic regimens. © 1998 John Wiley & Sons, Ltd.     

Expression of progesterone receptors in solid-cystic tumour of the pancreas

A role for sex hormones in the pathogenesis of solid-cystic tumour (SCT) of the pancreas is suggested by its predilection for young fertile women. Controversial data have been provided for the presence of progesterone receptors (PR) and/or oestrogen receptors (ER) in SCT. We report the immunohistochemical detection of PR in ten cases of SCT. Eight were from young women. The remaining two were from a post-menopausal woman and a young boy. All cases showed PR immunoreactivity in the large majority of neoplastic cells, whereas none exhibited ER positivity. In one tumour two types of cell populations were noted, the more anaplastic invasivetype being PR negative, whereas the more typical was PR positive. PR immunoreactivity in the absence of ER may simply reflect a lower sensitivity of ER antibody failing to reveal the biochemically detectable ER, or that the PR in cells of SCT are constitutively synthesized in an oestrogen-independent way, as in T47D breast carcinoma cell line, meningioma cells and some gastric cancer cells. Our findings support the hypothesis of a possible pathogenetic role of progesterone in SCT, independent of the patient's sex and age.     

Amine and peptide hormone production by lung carcinoid: a clinicopathological and immunocytochemical study

A consecutive series of 38 lung carcinoid tumours (36 surgical and two necropsy specimens) was studied. Histopathological features and amine and peptide hormone immunoreactivity were correlated with gross characteristics (size, location) and clinical data. Peripheral carcinoids were detected a decade later than central carcinoids and tended to be bigger. In general, the histological characteristics of peripheral and central carcinoids were similar; atypical features, however, were more common in peripheral carcinoids. Most carcinoids contained many argyrophilic cells (58%). Although argentaffinic cells were not found, serotonin immunoreactive cells were present in 32% of the tumours. Peptide hormone immunoreactivity (adrenocorticotrophic hormone (ACTH), calcitonin, somatostatin, gastrin) was rare. In one case massive ACTH production had caused clinically manifest Cushing's syndrome. In two other cases few ACTH immunoreactive cells were found and in one case calcitonin immunoreactive cells were present. The relative rarity of hormone production in lung carcinoids and the predominantly benign course of the tumour preclude the use of peptide hormone production as a prognostic indicator.     

Immunohistochemical study of chromogranin in 100 cases of pheochromocytoma,carotid body tumour,medullary thyroid carcinoma and carcinoid tumour

Summary Neuroendocrine cells have histologically common features represented by argyrophilic cytoplasm containing neuroendocrine granules. Neuroendocrine granules are composed of various kinds of peptide hormones, amines, carrier proteins and ATP. Although various kinds of peptide hormones have been detected in neuroendocrine tumours, a peptide hormone has not been required as a standard marker for these tumours. Chromogranin is a purified protein which binds catecholamines specifically and is recognized as a carrier protein. We carried out an immunohistochemical study of chromogranin immunoreactivity in 100 neuroendocrine tumours including pheochromocytomas, carotid body tumours, medullary thyroid carcinomas and carcinoid tumours. Marked immunoreactivity was observed in 85% of carcinoid tumours and 100% of the other tumour types. A non-functioning paraganglioma and a malignant carcinoid tumour without any other detectable marker also showed strong immunoreactivity to chromogranin. Chromogranin immunoreactivity is a useful tool for neuroendocrine tumours.     

Alpha-subunit immunoreactivity in plurihormonal pituitary adenomas of patients with acromegaly.

Twelve plurihormonal pituitary adenomas, removed surgically from 11 of 20 patients with acromegaly, were investigated. The mean age of the 11 patients was 45 yr. Seven patients with eight tumors were men. The tumors were immunostained for all known adenohypophysial hormones by the avidin-biotin-peroxidase complex (ABC) technique. All 12 adenomas were immunoreactive for growth hormone (GH) and alpha-subunit; prolactin (PRL) was detected in five tumors. Stains for the beta-subunits of glycoprotein hormones [thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH)] revealed immunopositivity for specific beta-subunits in ten adenomas. The close association between GH and alpha-subunit in pituitary tumors of acromegalic patients remains to be explained.     

Simultaneous production of the alpha-subunit of glycoprotein hormones and other hormones in pituitary adenomas

The immunohistological classification of 97 pituitary adenomas revealed in 34 cases alpha-subunit (a-su) positive cells in the tumor tissue. In 15 cases a-su was the only hormone found, in 11 cases the beta-subunits of the glycoprotein hormones could also be detected (10 cases with LH/FSH and 1 case with TSH). In 8 cases a-su was found simultaneously together with other hormones of the pituitary (ACTH and a-su in 1 case, GH and a-su in 4 cases, prolactin and a-su in 2 cases, prolactin, GH and a-su in 1 case). A-su could be demonstrated to be partly simultaneously produced together with these hormones in identical cells and secretory granules. Next to prolactin, the a-su was the second most frequently occurring hormone that could be detected immunohistologically in our material.     

Binding characteristics of monoclonal antibodies raised against bovine growth hormone

Monoclonal antibodies have been raised against pituitary bovine growth hormone using the hybridoma procedure. The binding characteristics of the seven selected monoclonal antibodies toward the antigen molecule in its native, chemically or enzymatically treated form have been studied. The reactivities of the monoclonal antibodies with growth hormones from other species and bovine prolactin have also been investigated. The epitopes recognized by four of the produced monoclonal antibodies are conformational, whereas two other monoclonal antibodies bind to sequential determinants. Three antibodies define immunological sites located between residues 6-124 of the bovine growth hormone molecule, and one of this antibody shows higher affinity to human than bovine growth hormone. The immunoreactivity of one monoclonal antibody is enhanced by the previous binding of the antigen to polyclonal antibodies, probably because of a localized conformational change of the bovine growth hormone molecule. This antibody also shows cross-reactivity with all the homologous hormones tested, indicating to recognize a highly conserved antigenic determinant.     

Folliculostellate cells in pituitary adenomas: Studies of hormonal profile and tumor vascularity

The hormonal immunoreactivity and vascularity of pituitary adenomas containing folliculostellate (FS) cells have been compared with those of tumors in which such cells were not identified. FS cells were present in variable numbers in 36 of 92 tumors. Adenomas immunoreactive for growth hormone (GH), adrenocorticotropic hormone (ACTH), or prolactin (PRL) contained FS cells in 40–50% of cases. Those immunoreactive for glycoprotein hormones and alphasubunit contained FS cells in 67–85% of cases, a statistically significant correlation. When alpha-subunit was also present in GH-, GH/PRL-, and ACTH-immunoreactive tumors, a higher proportion contained FS cells (57–91%). These data suggest a correlation between the presence of FS cells and glycoprotein immunoreactivity in pituitary adenomas. Vascular channels identified by the binding of the lectinUlex europaeus were quantified in the two types of tumors. Those containing FS cells were not more vascular than those without FS cells, which suggests that FS cells do not play a significant role in the regulation of intratumoraf vascularization in human pituitary adenomas.     

Morphology of the pituitary gland in ferrets (Mustela putorius furo) with hyperadrenocorticism

Pituitary tumours are the cause of hyperadrenocorticism in a variety of species, but the role of the pituitary gland in hyperadrenocorticism in ferrets is not known. In this species, the disease is mediated by the action of excess gonadotrophins on the adrenal cortex and is characterized by an excessive secretion of sex steroids. In this study, the pituitary gland of four healthy control ferrets, intact or neutered, and 10 neutered ferrets with hyperadrenocorticism was examined histologically following immunohistochemical labelling for adrenocorticotrophic hormone, alpha-melanocyte-stimulating hormone, growth hormone, thyroid-stimulating hormone, luteinizing hormone, follicle-stimulating hormone, and prolactin. Immunohistochemistry revealed that somatotrophs, thyrotrophs and lactotrophs were the most abundant cell types of the pars distalis of the pituitary gland in the healthy ferrets. The distribution of corticotrophs was similar to that in the dog and man. In ferrets, as in dogs, the melanotrophic cell was almost the only cell type of the pars intermedia. Gonadotrophs were found in the pars distalis of neutered, but not intact ferrets. All the ferrets with hyperadrenocorticism had unilateral or bilateral alterations of the adrenal gland. In addition, in the pituitary gland of two of these ferrets a tumour was detected. These tumours were not immunolabelled by antibodies against any of the pituitary hormones, and had characteristics of the clinically non-functional gonadotroph tumours seen in man. In some of the other ferrets low pituitary immunoreactivity for gonadotrophic hormones was detected, which may have been due to the feedback of autonomous steroid secretion by the neoplastic transformation of the adrenal cortex. It is concluded that initially high concentrations of gonadotrophins resulting from castration may initiate hyperactivity of the adrenal cortex. The low incidence of pituitary tumours and the low density of gonadotrophin-positive cells in non-affected pituitary tissue in this study suggest that persistent hyperadrenocorticism is not dependent on persistent gonadotrophic stimulation.     

Immunohistochemical galectin-3 expression in non-melanoma skin cancers

Galectin-3 is a ss-galactoside-binding lectin. It participates in a variety of normal and pathologic processes, including cancer progression. In this study, we evaluated the pattern of expression of galectin-3 in cutaneous squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), and its correlation with the grade of differentiation in SCC and tumor size. Galectin-3 expression was evaluated by immunohistochemistry in 31 SCCs, 30 BCCs, and 29 non-tumoral skin samples. Galectin-3 expression was higher in normal epidermis than in non-melanoma skin cancers, except for cytoplasmic immunoreactivity in SCC. Cytoplasmic galectin-3 immunoreactivity was significantly higher than nuclear immunoreactivity in non-melanoma skin cancers. Cytoplasmic galectin-3 immunoreactivity was significantly higher in SCC than in both circumscribed and infiltrative BCCs, but no difference was detected between these two types of BCC. Cytoplasmic galectin-3 immunoreactivity predominated within SCCs (p=0.000), and a positive correlation was detected between tumor size and cytoplasmic immunoreactivity (r=0.385, p=0.043). There was no correlation between galectin-3 staining and tumor differentiation and lymph node metastasis. Decreased nuclear galectin-3 expression and cytoplasmic immunoreactivity in tumors are important factors in the progression from the normal to the cancerous state in non-melanoma skin cancers. We speculate that cytoplasmic galectin-3 expression may be one of the factors that contribute to tumor aggressiveness in SCC.     

Human corticotroph cell adenomas

Sixty-one pituitary corticotroph adenomas from 47 patients with Cushing's disease, 10 with Nelson's syndrome, and four eucorticoid patients were studied by light microscopy, immunoperoxidase, and electron microscopy. Seventy nine percent of all tumors and 70% of Nelson's cases were microadenomas, sometimes minute. A contiguity between the posterior lobe and the adenoma was seen in ten cases. Spontaneous infarction of the tumor with remission of Cushing's syndrome occurred in one case. Light microscopy revealed that the adenoma cells were basophilic and contained PAS-positive granules also staining with Herlant tetrachrome and lead-hematoxylin. The granules stained positively with antiserum to adrenocorticotrophic hormone (ACTH), beta-lipotropic hormones (beta-LPH) and beta-endorphin. The most characteristic ultrastructural finding was the presence of perinuclear bundles of microfilaments found in all our cases. Oncocytic changes were seen in three tumors. Four silent corticotroph adenomas, two of them originally microadenomas that had enlarged to enclosed adenomas while being treated with bromocriptine for hyperprolactinemia and one a large diffuse invasive tumor, did not differ in their microscopic, immunocytological, or ultrastructural features.     

Human chorionic gonadotropin in lung and lung tumors. Immunohistochemical study on unbalanced distribution of subunits

To demonstrate unbalanced distribution of subunits of human chorionic gonadotropin (hCG) in the lung and lung tumors and to clarify its significance in differentiation and carcinogenesis of the lung, immunohistochemistry was performed on human fetus, infant, and adult lungs, and endocrine and nonendocrine tumors of the lung. Tissues were immunostained for alpha-subunits and for beta-subunits of glycoprotein hormones (hCG, luteinizing hormone, follicle stimulating hormone, and thyroid stimulating hormone), serotonin, and gastrin-releasing peptide. Immunoreactive alpha-subunit was first identified in endocrine-like cells at the 39th gestational week, and was found in all infant lungs and two-thirds of adult lungs. The hCG beta-immunoreactive cells were extremely rare in an adult lung, and were not found in fetus or infant lungs. The alpha-subunit-containing cells were present in neuroepithelial bodies, tumorlets, carcinoid tumors, and small cell carcinomas of the lung (SCCL). There were occasionally alpha-subunit-containing cells in non-SCCL but one of the carcinomas also contained many serotonin-positive and gastrin-releasing peptide-positive cells in the same region. All alpha-subunit-immunoreactive cells lacked immunoreactivity for beta-subunits of glycoprotein hormones, except some for hCG beta in one carcinoid tumor. Immunoreactive cells for isolated hCG beta appeared much more frequently in non-SCCL than in SCCL. Most non-SCCL containing hCG beta-positive cells did not show alpha-subunit-immunoreactivity. Thus, immunohistochemical distribution of hCG-subunits was unbalanced and hCG-subunits may be expressed through an independent mechanism, commonly in the lung and lung tumors. The significance of isolated alpha-subunit is further discussed in light of multidirectional differentiation of lung neoplasms (14, 17).     

GH-, PRL-, POMC-, beta-TSH-, beta-LH-, beta-FSH-mRNA in gonadotroph adenomas of the pituitary by in situ hybridization in comparison with immunostaining and clinical data

In situ hybridization (ISH) enables the visualization of specific mRNA for pituitary hormones. Our collection consists of 40 surgically removed pituitary adenomas that were classified as follicle stimulating hormone/luteinizing hormone (FSH/LH) cell adenomas by structure and by immunostaining (IH) for all pituitary hormones. All forty adenomas were regarded as clinically inactive. The aim of our study was to examine nonfunctioning adenomas by ISH for demonostration of mRNAs for all pituitary hormones. The results were compared with proliferation markers, invasiveness and clinical data. ISH detected signals for all pituitary hormones at a range of 30% for prolactin (PRL) to 85% for proopiomelanocortin (POMC). mRNA for β-FSH was detected in 70% and β-LH mRNA in 43% of adenomas. Thirty-three percent of adenomas revealed negative mRNA detection for β-LH but positive hormone content. The majority of adenomas (75%) expressed more than two mRNAs simultaneously, mostly the combination of POMC mRNA together with β-FSH mRNA and one to four others. Comparison with clinical data showed no significant differences except for one adenoma with a high Ki-67 index (>2.1% positive nuclei). This adenoma showed very high signals for PRL and β-TSH mRNA.