Immunohistochemical demonstration of cytokeratins in the human prostate

The behaviour of keratins in the human prostate is investigated immunohistochemically by polyclonal rabbit antibodies against keratins from human stratum corneum (kit from ORTHO/Heidelberg) and compared to the behaviour of prostatic acid phosphatase (PAP) and prostate-specific antigen (PSA). In normal glands and cribriform as well as adenomatous hyperplasia only basal cells contain keratin. The secretory epithelium is keratin-negative and in contrast to the basal cells PAP- as well as PSA-positive. In prostatic ducts and utriculus prostaticus keratin is demonstrable in basal cells and urothelium. As in normal glands, the light cylindric epithelium is keratin-negative and PAP- as well as PSA-positive. The cells in atrophic glands and postatrophic hyperplasia may contain keratin as well as PAP and PSA. Urothelial and squamous metaplasia are strongly keratin-positive. PAP and PSA are not found. The cylindric epithelium of the ejaculatory ducts contains keratin at many places. PAP and PSA are not demonstrable. The utriculus does not differ from normal prostatic glands immunohistochemically. This supports the view that the epithelium of the sinus urogenitalis is involved in the embryogenesis of normal prostatic glands and the utriculus as well. Urothelial and squamous metaplasia obviously arise from basal cells which share the same immunohistochemical features. Whether the cells in atrophic glands and postatrophic hyperplasia derive from basal cells or secretory epithelium cannot be decided. The keratin composition of the prostate should be further analyzed by keratin-specific monoclonal antibodies.     

Investigations of the estrogen (ER-ICA-test) and the progesterone receptor in the prostate and prostatic carcinoma on immunohistochemical basis

Summary Estrogen (ER) and Progesterone receptors (PR) were demonstrated immunohistochemically on frozen sections from 11 prostatectomy and 7 cystoprostatectomy specimens in the nuclei of various cell types. The periglandular fibrocytes and smooth muscle cells were extensively positive, the interglandular stromal cells were only partly so. Normal basal cells stained focally positive, hyperplastic basal cells stained extensively. The glandular secretory epithelium and atrophic glands were negative. The same findings were obtained in hyperplastic nodules. Both ER and PR also occurred in the urothelium of central prostatic ducts and of the prostatic urethra. The fibrous stroma around the ejaculatory ducts and seminal vesicles was extensively positive while the epithelium was negative. The smooth musculature of the seminal vesicles was only partly positive. On large field sections, the ER as well as the PR were numerically equally distributed throughout the inner zone of the prostate and the prostate proper. 12 prostatic carcinomas (G I–G III) were ER- and PR-negative. Estrogens may contribute to nodular hyperplasia by triggering a stromal proliferation with a secondary inductive epithelial growth. Obviously they do not act directly on prostatic carcinoma but inhibit growth via the hypophyseal-testicualr axis. The biological significance of the PR in the prostate is unknown.     

Expression of P-cadherin identifies prostate-specific-antigen-negative cells in epithelial tissues of male sexual accessory organs and in prostatic carcinomas. Implications for prostate cancer biology.

Cadherins constitute a family of calcium-dependent cell-cell adhesion molecules the individual members of which are essential for the sorting of cells into tissues during development. In this study, we examined the expression of E-cadherin, N-cadherin, and P-cadherin in tissues obtained from radical prostatectomies. Epithelial cells of prostatic glands, ejaculatory ducts, and seminal vesicles expressed E-cadherin but not N-cadherin. P-cadherin was expressed in epithelial cells of the seminal vesicles and ejaculatory ducts. In the prostate it was limited to the basal cells of prostatic acini, glands with basal cell hyperplasia, and atrophic glands denuded of the luminal cells. All P-cadherin-positive cells were negative for prostatic-specific antigen. Prostatic cancers were mostly P-cadherin negative, but some tumors had P-cadherin-positive areas frequently located close to ejaculatory ducts and negative for prostatic-specific antigen. The mutually exclusive expression of P-cadherin and prostatic-specific antigen suggests that these proteins are involved in differential mechanisms of cell regulation in prostate cancer. P-cadherin may become a useful marker in the diagnosis and management of patients with prostate cancer and low levels of prostatic-specific antigen.     

Effects of combination endocrine treatment on normal prostate, prostatic intraepithelial neoplasia, and prostatic adenocarcinoma.

AIMS--To investigate the effect of combination endocrine treatment (CET) or luteinising hormone releasing hormone agonist and flutamide on non-neoplastic prostate, prostatic intraepithelial neoplasia, and prostatic adenocarcinoma. METHODS--The morphology, including the mitotic activity, of 12 radical prostatectomies from patients with prostatic adenocarcinoma pretreated for three months with CET was evaluated in haematoxylin and eosin stained sections and compared with an untreated age and stage matched control group. RESULTS--A differential effect on the non-neoplastic prostate was observed. In fact, the transition zone of the treated prostate showed simplification of the glandular lobules: the ducts and acini were small without undulations of the epithelial border and with a prominent basal cell layer. Within the peripheral zone there was inconspicuous branching of the ducts and acini which looked dilatated and lined by flattened atrophic epithelium. Prostatic intraepithelial neoplasia occurred in scattered ducts and acini in the peripheral zone of 10 of the 12 patients. The epithelial cell lining showed a prominent basal cell layer. A certain degree of secretory cell type stratification was always present. However, crowding was less evident than in the untreated prostate because of cytoplasmic clearing and enlargement as a result of coalescence of vacuoles. The treated adenocarcinomas had neoplastic acini which looked small and shrunken, and areas of individual infiltrating tumour cells separated by abundant interglandular connective tissue. The secretory cells of the nonneoplastic, prostatic intraepithelial neoplasia, and prostatic adenocarcinoma lesions had inconspicuous nucleoli, nuclear shrinkage, chromatin condensation, and cytoplasmic clearing. Apoptotic bodies were easily identifiable in all the cell layers. The lumina were rich in macrophages, sloughed secretory cells with degenerative features, and apoptotic bodies. Mitoses were not observed in any of the treated non-neoplastic prostate, prostatic intraepithelial neoplasia, or prostatic adenocarcinomas, whereas the mitotic frequency increased from non-neoplastic prostate through prostatic intraepithelial neoplasia up to prostatic adenocarcinomas in the untreated specimens. CONCLUSIONS--CET before radical prostatectomy causes regressive epithelial changes together with enhanced apoptosis and blocked mitotic activity.     

Premalignant lesions of the prostate

Two putative premalignant lesions of the prostate have been identified. Prostatic intraepithelial neoplasia (PIN) is characterized by proliferation and anaplasia of cells lining ducts and acini. Atypical adenomatous hyperplasia (AAH) consists of a localized proliferation of small round glands without cytologic atypia. PIN and AAH may be confused with well-differentiated carcinoma as well as florid hyperplasia, basal cell hyperplasia, transitional metaplasia, seminal vesicular epithelium, and atypia due to inflammation, infarction, and radiation. These premalignant lesions appear to have a high predictive value for carcinoma, and their presence on prostatic biopsy warrants further search for concurrent invasive adenocarcinoma. The use of strict morphologic criteria and uniform nomenclature will ensure standardization in the diagnosis of premalignant lesions of the prostate.     

Fine structure of the canine prostatic complex

Summary The canine prostatic complex, including the prostatic urethra, the urethral openings of the prostatic gland ducts, the prostate gland proper and the ejaculatory ducts has been studied with the transmission and scanning electron microscopes. The urethral epithelium was found to be a modified transitional epithelium; it extended a short distance from the urethra into the orifices of the ducts where it gradually lost height. The columnar cells were replaced by cuboidal superficial cells in the terminal ducts of the gland. With increasing distance from the urethral openings of the ducts, the superficial cuboidal cells developed secretory activity and finally were indistinguish-able from regular prostatic secretory cells. The latter formed typical prostatic acini, consisting of secretory cells which were merocrine in nature, and flat lentilate basal cells. In addition to exocrine cells, three different types of presumptive endocrine cells occurred, predominantly in the periurethral ducts of the prostate gland. It has been concluded from this study that, firstly, fluid absorption and spermatophagy are the main functions of the epithelia of the ejaculatory ducts and the ampulla of the vas deferens. Secondly, it has been concluded that the different functions of the various structures of the prostatic complex can be related to their different embryological origins.The financial support of the Deutsche Forschungsgemeinschaft (Au 48/6) is gratefully acknowledged     

Distribution of lipochrome pigment in the prostate gland: Biological and diagnostic implications

Lipochrome pigment is characteristically found in Wolffian duct—derived structures including seminal vesicles and ejaculatory ducts. The presence of lipochrome pigment is helpful in identifying atypical histological patterns of seminal vesicle or ejaculatory duct that mimic prostatic adenocarcinoma. The authors studied the distribution of lipochrome pigment in 28 radical prostatectomy specimens using a modified Ziehl-Neelson stain and fluorescence microscopy. In all cases secretory epithelium of the central zone contained lipochrome pigment often in significant amounts (2 to 3+). Secretory epithelium from peripheral and transition zones in each of four specimens (14.3%) contained lipochrome pigment. In addition, occasional examples of nodular hyperplasia, prostatic intraepithelial neoplasia, and prostatic adenocarcinoma contained lipochrome pigment. The preferential distribution of lipochrome pigment in central zone epithelium adds further support to the hypothesis that central zone glands are derived embryologically from Wolffian duct (mesoderm) rather than urogenital sinus (endoderm), which gives rise to transition and peripheral zone glands. Furthermore, lipochrome pigment should not be used as the sole diagnostic criterion for separating atypical histological patterns of seminal vesicle and ejaculatory duct from those of prostatic origin.     

Distribution of keratin protein in normal prostate and prostatic tumors. An immunohistochemical study

Fifty cases (20 cases of benign hyperplasia, 30 cases of adenocarcinoma) of prostatic tissues were studied for expression of keratin. The basal cells were strongly and continuously positive in normal prostatic glands and in benign prostatic hyperplasia. The secretory cells and carcinoma cells were negative. The basal cells remained partially in intra-ductal carcinoma, revealing keratin positive cells in a spotty pattern. These findings may be useful in differential diagnosis between benign prostatic hyperplasia and carcinoma of the prostate.     

Calcifications in prostate and ejaculatory system: a study on 298 consecutive whole mount sections of prostate from radical prostatectomy or cystoprostatectomy specimens

Although calcifications in the prostate are a common manifestation, the relationship between calcifications and prostate cancer is not clearly documented as in breast cancer. In addition, anatomical distribution of calcifications by zones of the prostate and ejaculatory system has not been systematically studied. To study the frequency and patterns of calcifications within the prostate and ejaculatory system, we reviewed the whole mount sections of 298 consecutive prostatectomy or cystoprostatectomy specimens. Calcifications were evaluated in the prostate (central, peripheral and transition zones, and verumontanum), ejaculatory ducts, and seminal vesicles. We graded the degree of calcifications as mild, moderate, or severe. Calcifications in the prostate and ejaculatory system were common, and their frequency in our series is as follows: 88.6% (264/298) of prostates, 58.1% (173/298) of seminal vesicles, and 17.1% (51/298) of ejaculatory ducts. The prostatic calcifications occurred mostly in benign glands and/or stroma of all zones and the verumontanum. Calcifications were more common in the transition zone than other zones. There were 4 cases of prostatic calcifications in the areas of prostatic adenocarcinoma: 3 cases with calcifications in the tumor glands and 1 case with calcifications in tumor stroma but not in the accompanying tumor glands. In conclusion, calcifications are a very common finding in prostatectomy specimens and seem mostly to be associated with benign prostatic hyperplasia. However, calcifications can occur in direct association with prostatic adenocarcinoma, although the incidence of this association is not as high as in breast carcinoma. Also, ejaculatory system calcifications are not an infrequent finding.     

Prostatic neuroendocrine cells have a unique keratin expression pattern and do not express Bcl-2: cell kinetic features of neuroendocrine cells in the human prostate.

We investigated the keratin phenotype and bcl-2 immunoreactivity of neuroendocrine cells in the human prostate to determine whether the postmitotic status of these cells is associated with protection from apoptosis by bcl-2 protein expression and to elucidate the possible cell kinetic relationship between neuroendocrine cells and the other epithelial components of the prostate. Tissue specimens were selected from prostates of 19 patients harboring normal secretory glands (n = 15) and glandular benign prostatic hyperplasia (n = 10). Using a novel sequentially selective destaining immunoenzymatic cytochemical technique we were able to demonstrate the distribution of neuroendocrine cells, keratin markers identifying either basal, luminal, or intermediate cells, and the bcl-2 protein in single sections. Basal cell keratins were expressed in the minority of the neuroendocrine cells. In most of the cells, intermediate and luminal cell keratins were found and bcl-2 was constantly negative. Our findings indicate that neuroendocrine cells and other epithelial cells in the human prostate share a common keratin phenotype and probably originate from a common epithelial precursor. From the absence of bcl-2 we infer that the neuroendocrine cells have no progenitor cell characteristics.     

Loss of high-molecular-weight cytokeratin antigenicity in prostate tissue obtained by transurethral resections

OBJECTIVE: Staining of prostatic basal cells for the expression of high-molecular-weight cytokeratin has been suggested as a way of distinguishing benign from malignant prostate glands. We evaluated the utility of high-molecular-weight cytokeratin in the diagnosis of malignancy in prostate specimens obtained in various ways. DESIGN: Prostate tissues obtained from needle biopsies, transurethral resections, and total prostatectomies were immunostained with monoclonal antibody 34betaE12, an antibody directed against high-molecular-weight cytokeratins. RESULTS: Antiserum to high-molecular-weight cytokeratin only stained the basal cells in normal glands in 3 (12%) of 25 specimens obtained by transurethral resection. Other antigens, such as the alternate 10-nm filament protein vimentin, were unaffected and were detected in 100% of these specimens. However, keratin antigenicity in transurethral biopsies could be restored in these specimens by antigen retrieval in a low pH citrate buffer using a microwave heat technique. Keratin staining in needle biopsies and total prostatectomies was unaffected. CONCLUSION: In summary, our results indicate the technique of transurethral resection results in a specific loss of keratin antigenicity. This limits the utility of anticytokeratin 34betaE12 in interpreting transurethral resections without the application of antigen retrieval.     

Unusual prostatic carcinomas

Over 90% of malignant epithelial tumors of the prostate are common carcinomas. Uncommon or rare prostate carcinomas can histogenetically be related to 4 epithelial types of the prostate: the secretory epithelium, the basal cells, the endocrine cells and the transitional epithelium. The rare, purely mucinous carcinoma and the ductal papillary carcinoma belong to the type of secretory epithelium. The latter is rarely seen in the large central prostatic ducts, it develops more frequently in peripheral ducts and is combined with common prostate carcinoma. The so-called endometrioid carcinomas of the utriculus described in the literature are probably ductal prostate carcinomas. To date no carcinoma has been found in the utriculus. The adenoid cystic carcinoma of the prostate is a basal cell tumor with preponderantly good prognosis. Endocrine cells are disseminated in most common prostate carcinomas. Thereby mixed forms showing both portions of a common adenocarcinoma and of a carcinoid may occur. Pure carcinoids of prostate are rare findings. The small cell carcinoma of the prostate is the highly malignant variant of the endocrine cell type. Immunohistochemically, a multitude of proteohormones are demonstrable in endocrine tumor cells. The ectopic ACTH production with Cushing's syndrome is of particular clinical significance.     

Keratin immunoreactivity in fine-needle aspiration of the prostate: an aid in the differentiation of benign epithelium from well-differentiated adenocarcinoma

The efficacy of utilizing immunocytochemical staining of prostatic basal cells in separating benign from malignant prostatic epithelium was tested by staining fine-needle aspiration smears of prostatic lesions with the monoclonal antibody EAB-903. This antibody has been shown to stain keratin subtypes present in the prostate only in basal cells. The study utilized 12 benign, nine malignant, and four suspicious-for-carcinoma cases. Ten of 12 benign cases showed an intermingled pattern of staining, which was not found in the malignant cases. Our findings indicate that this distinctive pattern of staining may assist in distinguishing benign epithelium from well-differentiated prostatic adenocarcinoma.     

Cytokeratin and vimentin intermediate filament proteins in benign and neoplastic prostatic epithelium

Prostatic samples from 30 hyperplastic prostates and 61 prostatic adenocarcinomas were examined for vimentin and cytokeratins. The co-expression of cytokeratins and vimentin was found in all benign prostatic epithelium and in 83% of adenocarcinomas. Benign prostatic epithelium showed vimentin intermediate filaments distinctively distributed in the basal regions and as paranuclear sheaves along the long axis of the cell. This pattern of vimentin staining was seen in adenocarcinomas with low Gleason scores, whereas high-grade tumours showed intense diffuse perinuclear staining.     

Clear cell cribriform hyperplasia of the prostate. Immunohistochemical and DNA flow cytometric study.

Clear cell cribriform hyperplasia (CCCH) of the prostate is an unusual form of benign prostatic hyperplasia characterized by a nodular proliferation of clear cells with small, uniform nuclei. The authors studied 15 cases of CCCH by immunohistochemistry and 13 of them by DNA flow cytometry to establish the immunohistochemical and DNA profile of this lesion. Patients ranged in age from 58 to 88 years (mean, 68 years). Follow-up of a mean of 22 months showed all patients alive with no evidence of malignant prostatic disease. All 13 CCCHs showed diploid DNA content; in contrast, among 4 papillary/cribriform carcinomas of the prostate used for comparison, 3 were aneuploid and 1 was diploid. A basal cell layer was demonstrated in all 15 CCCHs by the use of the 34 beta E12 anti-high-molecular-weight keratin antibody (EAB-903) that reacts with the basal cells but not with the acinar cells of the prostate. A continuous basal cell layer was not evident in the carcinomas. The blandness of the epithelium, the well-defined nodular configuration, the presence of a basal cell layer demonstrable by immunocytochemistry, and the lack of aneuploidy as determined by DNA flow cytometry together lend support to the concept that CCCH is a benign lesion.     

Basal cell-specific and hyperproliferation-related keratins in human breast cancer.

In normal breast tissue and in noninvasive breast carcinomas, various keratin-14 antibodies were reactive predominantly with the basal/myoepithelial cell layer, although mainly in terminal and larger ducts luminal cells sometimes also were stained. A similar reaction pattern was found with an antibody directed against keratin 17, although this antibody was more often found negative than keratin 14 in the pre-existing myoepithelial cells in intraductal carcinomas. Furthermore antibodies reactive with hyperproliferation-related keratins 6 and 16 were used. One of these (LL025) was completely negative in normal breast tissue and noninvasive breast carcinomas. However 10% of the invasive carcinomas were diffusely or focally positive with this latter antibody, while in 18 of 115 cases of invasive breast carcinomas studied, a basal cell phenotype was detected. A relatively high concordance was found between the carcinomas immunostaining with the basal cell and the hyperproliferation-related keratins, but not between these markers and the proliferation marker Ki-67. This supports the conclusion that basal cells in breast cancer may show extensive proliferation, and that absence of Ki-67 staining does not mean that (tumor) cells are not proliferating.     

An immunohistochemical study of the breast using antibodies to basal and luminal keratins,alpha-smooth muscle actin,vimentin, collagen IV and laminin

Summary The distribution of simple epithelial (K8/18/ 19) and basal (myoepithelial) (K5/14) keratins, -smooth-muscle actin, vimentin, collagen IV and laminin in normal mammary glands and in benign proliferative lesions was studied using monoclonal antibodies (mAbs). These antibodies (Abs) identified myoepithelial cells and luminal cells specifically. In lesions with adenosis and papillomas, the two-layered formation resembled that of normal glands with a purely myoepithelial-epithelial differentiation. In scleradenotic lesions, the main cell was of myoepithelial immunophenotype with intermixed trabecular-tubular proliferations of simple-type epithelium. The sclerosis seems to be the result of an irregular basal lamina synthesis by the myoepithelial cells. In contrast to these lesions, epitheliosis represents a purely intraluminal cell proliferation of clearly simple epithelial immunophenotype and of cells with a basal keratin phenotype, lacking myoepithelial differentiation antigen actin. The basal keratin type epithelium may represent post-stem or intermediate cells developing into luminal epithelium. Epitheliosis appears to be a purely epithelial hyperplasia with striking similarity to the regeneration of normal breast epithelium. The different proliferative patterns may give an explanation for differences in potential cancer risks of patients with these lesions.Dedicated to Prof. Dr. G. Seifert on the occasion of his 70th birthday     

Cytokeratin and vimentin expression in normal and neoplastic canine prostate

Intermediate filament expression in the canine prostate, unlike that in human prostate, is represented in the literature by only a few reports. In this study, the expression of cytokeratin (CK) and vimentin was examined in three normal canine prostates and 11 canine prostatic carcinomas. Monoclonal antibodies directed against vimentin, CK AE1/AE3, CK 18-8 (for luminal epithelial cells), CK 5, CK clone 8.12 and CK 14 (for basal cells) were employed. As in man, normal canine prostatic luminal cells were positive for CK 8-18. Basal cells were positive for CK 5 and CK clone 8.12 but, in contrast to findings in man, were negative for CK 14. Luminal cells were vimentin-negative, whereas in man they have been reported as vimentin-positive. The majority of carcinomas showed an undifferentiated histological pattern and all were positive for CK AE1/AE3 and for vimentin. Ten tumours were positive for CK 8-12, but six of them showed many cells co-expressing CK 14. Moreover, in two of these six cases a large number of neoplastic cells also reacted with CK clone 8.12 antibody, and in one of them co-expression of CK 5 was detectable. This co-expression, of luminal and basal cytokeratins, suggests a possible origin of the tumours from prostatic epithelial stem cells. Vimentin expression is an inconstant finding in human prostatic carcinomas; its almost uniform occurrence in canine carcinomas suggests a lesser degree of differentiation than in the human neoplasm.     

The expression of keratins Nos. 8, 17 and vimentin in pleomorphic adenoma of the salivary glands

In the normal salivary gland, the monoclonal antibody to keratin 8 immuno-morphologically identifies the epithelium that covers acini and ducts. The monoclonal antibodies to keratin 17 and vimentin detect normal myoepithelium. The two keratins are found both in the epithelioid and mesenchyma-like components of pleomorphic adenoma, suggesting a single epithelial nature of this tumor. In all the morphological components of the pleomorphic adenoma, there are cells that combine protein expression of intermediate filaments normally labelling different cell subpopulations. This fact provides support for the hypothesis that the pleomorphic adenoma originates from bipotent precursor cells. A particular phenotype of pleomorphic adenoma elements is realized under the control of the local density of cells and microenvironment, as a result of which the cells expressing vimentin predominate in the mesenchymal component, keratin 8 in the epithelial tubular one.     

Keratin filaments in epithelial cells of the excretory ducts of rabbit submandibular glands--an immunohistochemical and ultraimmunohistochemical study

To clarify the roles of various keratin proteins, the distributions of eight keratin intermediate filament proteins (keratins 7, 8, 10, 13, 14, 18, 19 and 20) in the epithelial cells of the excretory ducts of rabbit submandibular glands were studied immunohistochemically and ultraimmunohistochemically. The epithelia of excretory ducts were composed of columnar cells and basal cells. In the columnar cells, intermediate filaments formed a network at the apical area, that is, an apex network connected with desmosomes. Keratins 7, 18 and 20 were detected in the upper layer of the network and keratins 8, 18 and 20 in the lower layer. The intermediate filaments containing keratin 7 were also connected with hemidesmosomes on the basal side. Keratins 7, 18 and 20 were found throughout the entire cytoplasm of the columnar cells. Keratins 8 and 14 were expressed near the nucleus, forming a ring-like structure around the Golgi apparatus in the columnar cells. In the basal cells, by contrast, the intermediate filaments were concentrated around the nucleus, forming a juxtanuclear network which contained keratin 10. Keratin 13 was detected between the juxtanuclear network and the cell membrane, and was connected with both desmosomes and hemidesmosomes. Kratin 7 filaments were contained throughout the entire cytoplasm of the basal cells. These results suggested that different functional subsets of keratin filaments could be distinguished in the epithelial cells of the excretory ducts of the submandibular glands. In the columnar cells, keratins 7, 8, 18 and 20 play a role in cell-cell contact or cell-matrix contact, and both keratins 8 and 14 seem to be involved in the structure of the Golgi apparatus. In the basal cells, keratin 10 may serve to position and anchor the nucleus within the cell, and keratin 13 plays a role in cell-cell and cell-matrix contacts.