Immunoexpression of inhibin alpha subunit, inhibin/activin betaA subunit and CD99 in ovarian tumors

OBJECTIVE: Anti-inhibin alpha and inhibin/activin betaA subunit and anti-CD99 monoclonal antibodies (mAbs) have recently been demonstrated to be able to label ovarian granulosa cells; thus, they may be of value in the diagnosis of granulosa cell tumors. The present study aimed to determine what combination of these mAbs may be useful for the differential diagnosis of sex cord-stromal tumors of ovary. DESIGN: Immunohistochemical analyses with anti-inhibin alpha and inhibin/activin betaA subunit antibody and anti-CD99 mAb were performed on 42 ovarian tumors, including sex cord-stromal tumors (29), ovarian epithelial cancers (10), and Krukenberg tumors (3). RESULTS: All sex cord-stromal tumors were positive for inhibin alpha subunit, and 17 cases (58.6%) of sex cord-stromal tumors were immunoreactive for inhibin/activin betaA subunit. Epithelial tumors and Krukenberg tumors were all negative for inhibin/activin betaA subunit except mucinous carcinoma, which showed strong cytoplasmic immunoreactivity. All sex cord-stromal tumors except one granulosa cell tumor showed membranous staining for CD99. A case of serous carcinoma and a case of mucinous carcinoma were positive for CD99, and the remaining epithelial tumors and Krukenberg tumor were all negative for CD99. CONCLUSIONS: The results of immunohistochemical analysis, together with literature review, suggest that inhibin alpha subunit may be a useful diagnostic marker for sex cord-stromal tumor of the ovary. In addition, anti-CD99 antibody may be useful for the differential diagnosis between ovarian tumors. Inhibin/activin betaA subunit has a limited usefulness in the differential diagnosis of ovarian tumor because of its wider immunoreactivity for both sex cord-stromal tumors and mucinous carcinomas. The differential diagnosis of sex cord-stromal tumors of the ovary would be better made with a combined use of both anti-inhibin alpha subunit and anti-CD99 mAbs.     

Immunolocalization of inhibin and activin subunits in human endometrium across the menstrual cycle

Inhibin/activin alphaC/alphaN and betaA subunits were localized immunohistochemically in the human endometrium throughout the menstrual cycle using an affinity-purified sheep polyclonal antibody raised against the alphaC/alphaN subunit and an affinity-purified rabbit polyclonal antibody raised against the betaA subunit. The betaB subunit was below the level of detection in all human endometrial samples tested. Immunoreactive inhibin alphaC/alphaN subunit was localized in the luminal epithelium, glandular epithelium, stromal tissues and vascular endothelium with no significant variation across the normal menstrual cycle. Immunoreactive betaA subunit, common to inhibin A and activins AA and AB was localized in the luminal and glandular epithelium and in migratory cells while the endometrial stromal cells, decidua, vascular smooth muscle and endothelium were devoid of immunoreactivity. A significant variation of immunoreactive betaA subunit was observed in glandular and luminal epithelium across the normal menstrual cycle. In proliferative endometrium, only a very low level of betaA immunostaining was seen in luminal and glandular epithelium, while the luminal epithelial staining increased significantly in the early secretory phase and remained relatively constant over the rest of the menstrual cycle. A progressive increase in betaA immunoreactivity was observed also in the glandular epithelium during the secretory phase reaching a maximum in the late secretory phases, and decreasing at menstruation. Co-localization studies on serial sections suggested that the migratory cells expressing strong betaA immunoreactivity were macrophages and neutrophils but not eosinophils or mast cells. Thus, cells within the human endometrium are capable of expressing inhibin/activin molecules in vivo. The variation in the pattern of secretion of the betaA subunit across the menstrual cycle suggests that activin peptides may have a physiological role in endometrial function.      

Adenocarcinomas of various sites may exhibit immunoreactivity with anti-inhibin antibodies

AIMS: The aim of this study was to investigate the immunohistochemical staining of adenocarcinomas arising primary at a variety of sites with antibodies against the alpha and beta subunits of human inhibin. We wished to determine whether positivity in an adenocarcinoma is specific for an ovarian primary. METHODS AND RESULTS: Seventy-eight adenocarcinomas were stained with the commercially available monoclonal antibodies R1 and E4 which react against the alpha and betaA subunits of human inhibin, respectively. In 20 adenocarcinomas, there was positivity with R1 and 46 cases were immunoreactive with E4. Positive staining was generally weak although there was strong reactivity with R1 in five cases and with E4 in two cases. CONCLUSIONS: Positive staining with antibodies against the alpha and beta subunits of inhibin may be present in adenocarcinomas arising primary at a variety of sites. Caution should be exercised when using anti-inhibin antibodies to distinguish between an ovarian carcinoma and a sex cord-stromal tumour. These antibodies should always be used as part of a panel. Positivity with anti-inhibin antibodies in an adenocarcinoma is not specific for an ovarian primary.     

Inhibin/activin subunits beta-A (-betaA) and beta-B (-betaB) are differentially localised in normal, hyperplastic and malignant human endometrial tissue

Inhibins (INHs) are dimeric glycoproteins composed of an alpha (-alpha) subunit and one of two possible beta (beta-) subunits (betaA or betaB). The aims of this study were to determine the frequency and distribution of INH beta (betaA and betaB) subunits in normal, hyperplastic and malignant human endometrium. Endometrial tissue was obtained from normal, hyperplastic (simple, complex and atypical) and endometrioid adenocarcinoma (EC) and INH-alpha, -betaA and -betaB were labelled using immunohistochemistry and immunofluorescence. INH-betaA and -betaB labelling was increased significantly between the proliferative and secretory phase (p<0.05). The lowest labelling was demonstrated in EC, being significantly lower than in secretory phase (p<0.01) and in simple, complex and atypical hyperplastic tissue (p<0.05). For inhibin-betaB, the most intense labelling was noted in atypical hyperplasia compared to EC (p<0.05). A strong colocalisation of inhibin-alpha and -betaA could be demonstrated in malignant endometrial tissue, suggesting the production of inhibin A within the tumour. Additionally, only limited colocalisation of inhibin-betaB with -alpha subunit could be observed, suggesting the synthesis of activin B rather than inhibin B in malignant endometrium. In conclusion, INH-betaA and -betaB were labelled in normal, hyperplastic and malignant endometrium. Hyperplastic tissue labelled more intensely than EC for the presence of INH-betaA and -betaB, suggesting a substantial function in endometrial pathogenesis and an important role in endometrial carcinogenesis.     

Axillary apocrine carcinoma with benign apocrine tumours: a case report involving a pathological and immunohistochemical study and review of the literature

BACKGROUND: Apocrine carcinoma is rare and often occurs in the axilla. This is the second apocrine carcinoma arising in bilateral axillae with associated apocrine hyperplasia to be reported. AIMS/METHODS: Because benign apocrine tumours may be precursors of cancer, this case was investigated immunohistochemically and histologically, and a literature (English and Japanese) review undertaken of cases with coexistent malignant and benign apocrine tumours in the axilla to elucidate the relation between apocrine carcinoma and benign apocrine tumours. RESULTS: Only four cases of axillary apocrine carcinoma with benign apocrine tumours were identified in the literature. In each case, benign apocrine hyperplasia was situated within and surrounding the adenocarcinomatous nests. Staining for epithelial membrane antigen revealed three patterns: (1) poorly differentiated tumour cells showing strong cytoplasmic staining; (2) combined luminal surface and cytoplasmic staining of glandular cells; and (3) a strongly positive lineal staining pattern at the luminal membrane surface, comprising one or two apocrine hyperplastic secretory cells. The basal lesions of apocrine hyperplasia were strongly positive for alpha smooth muscle actin, whereas the periphery of adenomatous lesions showed weaker positive staining, even though the periphery of adenocarcinomatous lesions was negative. CONCLUSIONS: All five apocrine carcinomas with benign apocrine tumours occurred in elderly Japanese men who had bilateral benign apocrine tumours even if affected by unilateral axillary apocrine carcinoma. The immunohistochemical results support the notion that apocrine hyperplasia is a precursor of cancer and that apocrine carcinoma, adenoma, and hyperplasia may be successive steps in the linear progression to carcinoma.     

Extramammary Paget disease is characterized by the consistent lack of estrogen and progesterone receptors but frequently expresses androgen receptor

Extramammary Paget disease (EPD) is an uncommon cutaneous malignant neoplasm that arises in areas rich in apocrine glands (perineum, vulva, and axilla). Apocrine gland origin or apocrine differentiation of cells of EPD has been suggested. Estrongen, progesterone, and androgen hormone receptors have been reported to exhibit a characteristic pattern of expression in mammary apocrine type carcinomas; however, their expression in EPD has not been elucidated fully. By using immunohistochemical methods, we studied the expression of steroid receptors in EPD on formalin-fixed paraffin-embedded tissue samples from 28 patients with EPD without associated visceral malignant neoplasms or adnexal carcinoma. Androgen receptor (AR) was identified in 15 of 28 cases. The proportion of AR-positive cells varied from 1% to more than 75%; 8 cases expressed AR in more than 10% of cells. Strong AR expression also was seen in the invasive carcinoma arising from 1 case of EPD. All cases lacked immunohistochemically detectable estrogen and progesterone receptors. The immunophenotype characteristic of apocrine carcinomas (AR-positive, estrogen receptor-negative, progesterone receptor-negative) was seen in a substantial proportion of EPD cases. Results suggest that AR expression is a factor in pathogenesis of EPD. This may be important for the therapy of recurrent or invasive disease.     

Expression of oestrogen receptor-beta in apocrine carcinomas of the breast

AIMS: Apocrine carcinoma of the breast seldom expresses oestrogen receptors (ER) or progesterone receptors (PR), but frequently expresses androgen receptors (AR). Because of this unusual hormone receptor status, it has been suggested that oestrogens have a less important role in the pathogenesis of apocrine carcinoma. The ER status of apocrine carcinoma has been studied for one kind of ER, the classic receptor now named ER-alpha; however, the status of ER-beta, a secondary oestrogen receptor, has not been examined systematically in apocrine carcinoma. The aim was to study ER-beta status in apocrine carcinoma. METHODS AND RESULTS: The expression of ER-beta was examined immunohistochemically in 48 apocrine carcinomas and compared with clinicopathological factors and ER-alpha, PR and AR status. ER-beta positivity was observed in 35 cases (73%), regardless of any clinicopathological factors or the status of other receptors. The results of ER-beta mRNA analysis supported the immunohistochemical results. CONCLUSIONS: The significance of oestrogens in apocrine carcinoma should not be dismissed at present when the role of ER-beta remains to be determined. Studying the action of oestrogen or antioestrogen in apocrine carcinoma may reveal a role for ER-beta independent of ER-alpha and raise the potential of hormonal therapy for these tumours.     

Localization of plasminogen activator and inhibitor, LH and androgen receptors and inhibin subunits in monkey epididymis

Epididymis is a site of sperm maturation and storage. Limited and directed-proteolysis regulated by plasminogen activator (PA), plasminogen activator inhibitor type-1 (PAI-1) and other related factors may play an essential role in these processes. Our previous studies have demonstrated that rat epididymis expressed luteinizing hormone receptor (LHR), tissue type (t) and urokinase type (u)PA, mRNAs, and tPA activity was stimulated in vitro by human chorionic gonoadotrophin (HCG). In the present study we further examined localization of mRNAs for tPA, uPA, LHR, androgen receptor (AR), as well as inhibin subunits alpha, betaA and betaB in rhesus monkey epididymis. Using in-situ hybridization with digoxygenin-labelled cRNA probes, we have demonstrated that tPA and PAI-1 mRNAs were localized in epithelial cells of adult monkey epididymis. uPA mRNA was localized in the same areas, but to a much smaller extent. tPA, uPA and PAI-1 mRNAs were greatly expressed in the caput and corpus of adult epididymis than in other regions. In-vitro experiments showed that both tPA and uPA activities in epididymal cells were dramatically stimulated by HCG, but not by follicle stimulating hormone (FSH). LHR (but not FSH receptor) and AR mRNAs were localized in the epithelial cells of the epididymis. However, LHR mRNA was detected in both adult and immature infant monkeys, whereas AR was found only in the adult. Inhibin alpha, betaA and betaB mRNAs were also detected in this organ, betaA mRNA being more strongly expressed in the caput than in other regions of the epididymis. We suggest that LH and androgen may be the key hormones in coordination with the PA-PAI-1 system in regulating epididymal differentiation and sperm maturation.      

Source of circulating levels of inhibin A, pro alpha C-containing inhibins and activin A in early pregnancy

It is now established that the glycoprotein hormone inhibin is produced by primate granulosa cells, corpus luteum and trophoblast of human placenta. This study was designed to investigate the major source of inhibins and activin A in early pregnancy using a novel panel of assays with high specificity and sensitivity. A total of 12 women (aged 20-35 years) with singleton pregnancy undergoing first trimester (group 1: 6- 8; group 2: 8-10; group 3: 10-12 weeks of gestation) termination of pregnancy (TOP) was recruited for the study. Blood samples were taken before TOP, every 15 min for the first hour and hourly for the next 3 h after TOP (total of 4 h of measurements). Circulating concentrations of inhibin A, pro alpha C, activin A, human chorionic gonadotrophin (HCG), oestradiol and progesterone were higher in early pregnancy than at any stage of the menstrual cycle. Peripheral concentrations of inhibin A and activin A were significantly decreased within the first hour in all three groups and gradually decreased to even lower concentrations within the study period. Pro alpha C concentrations decreased within the first hour and then remained unaltered during the next 3 h. Similarly, HCG, oestradiol and progesterone concentrations in circulation decreased substantially within 4 h of TOP. Correlation analyses showed a significant positive correlation (P < 0.001) between inhibin A, activin A, HCG, and oestradiol concentrations throughout the study period. In summary, this study shows that the feto-placental unit is the major source of increased circulating concentrations of inhibin A in early pregnancy. Activin A is produced by the feto-placental unit and the corpus luteum. Pro alpha C-containing inhibins are mainly secreted by the corpus luteum in early pregnancy.      

Physiological relationships between inhibin B, follicle stimulating hormone secretion and spermatogenesis in normal men and response to gonadotrophin suppression by exogenous testosterone

Inhibin has been postulated to be secreted by Sertoli cells in response to follicle stimulating hormone (FSH) and in turn to exert an inhibitory effect on FSH production. We have investigated this relationship using an assay specific for dimeric inhibin B. A total of 56 normal men received 200 mg testosterone enanthate (TE) i.m. weekly, for 65 +/- 1 weeks in a trial of hormonal male contraception. Before treatment a significant negative correlation between inhibin B and FSH concentration (r = 0.49, P < 0.001) was observed. During TE treatment, luteinizing hormone (LH) and FSH were rapidly suppressed. This was followed by a parallel decline in inhibin B and sperm concentration. During the early recovery phase, inhibin B concentrations remained suppressed in men who showed a delay in resumption of spermatogenesis, despite higher FSH concentrations. Inhibin B returned to pretreatment concentrations after 24 weeks recovery, when the inverse relationship with FSH was restored. Our results showed the expected inverse physiological relationship between inhibin B and FSH in normal men, with a decline during TE treatment and alpha subsequent resumption of the inverse relationship during recovery. These data clearly support the hypothesis that inhibin B plays a physiological role in the feedback control of FSH secretion, and reflects FSH-stimulated Sertoli cell function.      

Immunohistochemical localization of integrins in the normal, hyperplastic, and neoplastic breast. Correlations with their functions as receptors and cell adhesion molecules.

Integrins comprise a family of transmembrane glycoproteins that modulate cell-matrix and cell-cell relationships by acting as receptors to extracellular protein ligands, and also as direct adhesion molecules. The authors studied by immunohistochemistry the distribution of the alpha 1-6,v and the beta 1,3,4 subunits of integrins in samples of normal breast, the spectrum of fibrocystic disease (FCD), and representative benign and malignant neoplasms. Monoclonal antibodies (Mabs) specific for each subunit were applied to cryosections by the avidin-biotin-complex method; selected samples were studied by double immunofluorescence microscopy with the Mabs and a polyclonal antiserum to myosin. The authors found that the alpha 1-3,6,v and the beta 1, integrin subunits were detectable in the normal breast parenchyma; myoepithelial cells were consistently more prominently stained than the basolateral aspect of the luminal cells. This immunoprofile was retained, and in cases enhanced through the spectrum of FCD, in benign tumors and in ductal and lobular carcinomas in situ. In most infiltrating ductal carcinomas, integrin staining tended to decrease except for some cases that reacted strongly for the alpha v subunit. Several mucinous carcinomas reacted strongly for alpha 2,3,6,v and beta 4 subunits, and even more so for the alpha 5 subunit that was not found in the normal breast. Subsets of infiltrating lobular carcinomas stained convincingly for alpha 1,3,6,v and beta 1 subunits in delicate but abundant kinetopodia. Our findings indicate that in hyperplasias and in benign tumors integrin expression patterns parallel those of the normal breast, whereas in carcinomas, variations include decrease, enhancement, and emergence of certain subunits that are not in the normal repertory. Alterations of integrin expression parallel phenotypic changes in breast carcinoma cells; they also reflect their disrupted interaction with the similarly disrupted extracellular matrix. Enhancement of certain integrins in some carcinomas may reflect the selection of subpopulations with increased binding capacity which in turn may impact on their invasive and metastatic properties.     

Direct evidence for concurrent morphological and genetic heterogeneity in an invasive ductal carcinoma of triple-negative phenotype

Triple-negative breast cancers account for 12-17% of all invasive breast carcinomas and comprise a heterogeneous group of tumours, with varying histological features and clinical behaviours. Focal apocrine differentiation can be associated with a subset of these lesions. To establish whether morphological diversity is associated with divergent genetic aberrations the genomic profiles of microdissected, morphologically distinct components from an invasive ductal carcinoma of no special type with triple-negative phenotype and a region of apocrine differentiation were determined by high-resolution microarray-based comparative genomic hybridisation and validated by fluorescence in-situ hybridisation. Morphologically distinct components were found to harbour differing genetic aberrations, with the region of apocrine differentiation demonstrating genomic gains and losses on chromosome arms 9p and 9q, respectively, not present in non-apocrine areas. The results provide additional direct evidence of intra-tumour genetic heterogeneity in breast cancer and demonstrate that morphologically distinct regions can be associated with distinct genetic aberrations.     

Healthy women and patients with endometriosis show high concentrations of inhibin A, inhibin B, and activin A in peritoneal fluid throughout the menstrual cycle

Inhibin A, inhibin B, and activin A are growth factors which play local autocrine/paracrine roles in reproductive tissues. Since peritoneal fluid hormone content may reflect in part ovarian and endometrial secretory activities, the present study aimed to evaluate: (i) whether inhibin alpha-, activin betaA- and betaB-subunits, and activin receptor type II and type IIB mRNA are expressed in peritoneal tissues; (ii) expression and secretion of inhibin A and B, and activin A in cultured endometriotic cells; and (iii) concentrations of inhibin A and B, and activin A in serum and in peritoneal fluid in healthy women and in patients with endometriosis throughout the menstrual cycle. A group of women (n = 72) was recruited at laparoscopy for infertility investigation and divided into two groups: (i) control healthy women (n = 35), (ii) women with endometriosis (n = 37). Both groups were subdivided according to the follicular and luteal phase of the menstrual cycle. At the time of laparoscopy, specimens of peritoneal tissues were collected from three healthy women, while endometriotic tissue samples were collected and cultured from three women with endometriosis. Peritoneal tissues and cultured endometriotic cells expressed inhibin alpha-, activin betaA-, and betaB-subunits, and activin receptors mRNAs; in addition, inhibin-related proteins were measurable in culture medium. In healthy women, inhibin A and B, and activin A concentrations in peritoneal fluid were significantly higher than in serum (P < 0.001), at both phases of the menstrual cycle. Peritoneal inhibin A and B, and activin A concentrations were not significantly different between healthy women and patients with endometriosis, either when evaluated according to the degree of the disease and/or to the phase of the menstrual cycle. In conclusion, the findings that high concentrations are present in peritoneal fluid and that menstrual cycle-related changes occur suggest that reproductive organs may contribute to inhibin-related proteins in peritoneal fluid.      

Immunohistochemical staining of normal, hyperplastic, and neoplastic adrenal cortex with a monoclonal antibody against alpha inhibin.

AIMS: To investigate the immunohisto-chemical staining of normal, hyperplastic, and neoplastic adrenal cortex with a monoclonal antibody against alpha inhibin. Also, to determine whether immunostaining with this antibody is useful in differentiating between adrenal cortical neoplasms and other tumours involving the adrenal gland that might mimic them. METHODS: Normal adrenal tissue (n = 20) and specimens from cases of adrenal hyperplasia (n = 13), adrenal cortical adenoma (n = 15), adrenal cortical carcinoma (n = 4), phaeochromocytoma (n = 8), and adrenal metastatic tumour (n = 7) were stained with a monoclonal antibody against the alpha subunit of human inhibin. RESULTS: Positive staining with the anti-alpha inhibin monoclonal antibody was seen in all normal adrenal glands. Immunoreactivity was largely confined to the inner cell layers of the adrenal cortex, with no staining of the adrenal medulla. All hyperplastic adrenal glands and adrenal cortical adenomas and carcinomas were also immunoreactive. The other tumours studied were negative. CONCLUSIONS: There is consistent immunoreactivity with the anti-alpha inhibin monoclonal antibody in normal adrenal cortex and in hyperplastic and neoplastic adrenal cortical lesions. In the normal adrenal cortex, positive staining is mainly confined to the zona reticularis. Other neoplasms involving the adrenal gland are negative. Immunohistochemical staining with anti-alpha inhibin monoclonal antibody, performed as part of a panel, may prove to be of value in the distinction between adrenal cortical carcinoma and phaeochromocytoma or metastatic tumour.     

The enigmatic nature of apocrine breast lesions

Epithelial cells of fetal breast glandular structures, at the third trimester of pregnancy (28 weeks), produce GCDFP-15, in the absence of specific apocrine morphology. Apocrine epithelium of the breast may be a normal process of differentiation rather than a result of metaplasia, and it has been demonstrated that it is estrogen-receptor, progesterone-receptor and bcl-2 negative, but androgen-receptor (AR) positive. The significance of AR expression in apocrine epithelium is uncertain. Apocrine epithelium is seen in a wide spectrum of breast entities, ranging from benign lesions to invasive carcinoma. Breast cancer accounts 32% of all cancer cases among women and is the most common type of cancer in women. Little is known about breast carcinogenesis. Widely, it is accepted that breast cancer, like most other type of cancer, is being developed through the accumulation of genetic aberrations. Apocrine epithelium may reflect instability of the breast epithelium, creating an environment favouring further oncogenic alterations. In the last decade, several lines of evidence support the idea that some breast benign epithelial apocrine lesions are clonal lesions and may be considered as truly pre-malignant or precursors of breast carcinoma. Apocrine changes in many cases do not present any diagnostic difficulty; on the other hand, apocrine proliferations with cytologic atypia can be particularly difficult and challenging. The purpose of this study is to collect and highlight the areas of consensus in the literature as well as the controversial areas concerning the apocrine epithelium of the breast.     

Androgen receptor expression in ductal carcinoma in situ of the breast: relation to oestrogen and progesterone receptors

AIMS: Ductal carcinoma in situ (DCIS) of the breast has been diagnosed increasingly since the advent of mammographic screening. In contrast to the situation in invasive breast carcinoma, there are no reports on androgen receptor (AR) status in DCIS and few reports on oestrogen (ER) and progesterone (PR) receptors. METHODS: AR expression was examined in 57 cases of DCIS of the breast and correlated to the degree of differentiation and ER/PR status using immunohistochemical methods. RESULTS: AR positivity was noted in 19 of the cases, whereas the other 38 cases were negative. There was no significant association between AR expression and the degree of differentiation of DCIS; three of the 13 well differentiated DCIS cases, 10 of the 19 intermediately differentiated cases, and six of the 25 poorly differentiated cases were positive (p = 0.093). However, a strong association was shown between the expression of ER (p < 0.0001) and PR (p = 0.002) and the degree of differentiation of DCIS. In addition, no significant association was found between the expression of AR and the expression of ER (p = 0.26) or PR (p = 0.57) in DCIS of the breast. CONCLUSIONS: A large number of cases of DCIS of the breast express AR and this may be associated with apocrine differentiation, which may impact on accurate typing of DCIS. Moreover, the expression of AR (but not ER or PR) in DCIS does not appear to be associated with the degree of differentiation.