[Morphogenesis and significance of epithelial metaplasia in the human prostate gland. An electron-microscopic study (author's transl)]

Biological tissue markers in benign and malignant disease of the human prostate

Immunoperoxidase techniques were used to study, the distribution of peanut agglutinin receptors, blood group isoantigens and several epithelial antigens in hyperplasia, adenosis, microcarcinoma and well differentiated adenocarcinoma of the prostate. Intraluminal and luminal surface PNA receptors were seen in all well differentiated carcinomas, 53% of microcarcinomas and 50% of adenosis, while no such sites could be demonstrated in benign hyperplasia. The expected blood group isoantigen was expressed in 75% of benign hyperplasias. When compared to the hyperplastic epithelium nearby, appropriate ABH expression was seen in 60% of adenosis, 47% of microcarcinomas and 25% of well differentiated carcinomas. A keratin antibody specifically labelling the basal cells in the normal prostate identified a subset of well differentiated carcinomas with preferential staining of the apical cytoplasm while microcarcinomas and adenosis were consistently negative. Our study establishes a highly ordered PNA receptor distribution in prostatic epithelia; it confirms early changes in the expression of ABH isoantigens in epithelial proliferative disorders of the prostate; it identifies a subset of keratin-positive well differentiated carcinomas, possibly of different ontogeny.

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.

Phenotypic modulation of the canine prostate after long-term treatment with androgens and estrogens

Fine structural alterations of the canine prostate induced by long-term treatment of castrated adult animals with estrogens and/or androgens and also in combination with antiandrogens and/or antiestrogens for six months have been studied with particular respect to their topographic location within the gland. Three major patterns of structural responses of the epithelium have been distinguished: squamous metaplasia, atrophy, and hypertrophy, while in stroma, regression, hypertrophy, or sclerosis were observed. In addition to cellular alterations of stromal fibrocytes and smooth muscle cells, characteristic changes in the arrangement, distribution, and pattern of the different stromal elements occurred. General squamous metaplasia of the epithelium and regressive alterations of stromal cells were most obvious in animals treated with estradiol plus androstanediol. Atrophy of the epithelium and stromal sclerosis were the salient features of antiandrogen-treated castrated animals, while hypertrophy or hyperplasia of both the epithelium and stroma was a major finding in androstanediol-substituted castrated animals. Combined treatment caused rather heterogeneous structural patterns seemingly dependent on the location within the gland. The results indicate that the prostatic epithelial cells dispose of a broad variety of structural reaction patterns that, in case of combined hormonal treatment, are expressed in a manner typical for their locations within the ductal system of the gland. However, with the exception of combined treatment with estradiol, tamoxifen, and androstanediol of castrated dogs, none of the experimental protocols used induced a morphologic response of the gland comparable to that seen in human benign prostatic hyperplasia. The canine prostate therefore is of rather limited value as a model for human BPH.

Immunohistochemistry of acid phosphatase in the human prostate: normal and pathologic. Cytochemistry and biochemistry of acid phosphatases II

Three different antisera against human prostatic acid phosphatase were used for direct and indirect immunohistochemical demonstration of acid phosphatase in paraffin sections of infantile and adult normal, hyperplastic and carcinomatous prostatic tissue. All antisera were prepared in rabbits. Antiserum A was prepared from highly purified acid phosphatase extracted from autopsy specimens. Antiserum B was a concentrate of a commercial antiserum used in radioimmunoassay and was prepared from purified extracts of human seminal fluid. Antiserum C was a peroxidase-conjugated antiserum prepared from purified extracts of human seminal fluid. The specificity of the three antisera was compared using different immunohistochemical methods and tissues. It was comparably high in all three antisera which gave only slightly different staining results in prostatic tissue. The staining results in prostatic carcinoma were only dependent on the titer of the respective antiserum. Carcinomas with a cribriform growth pattern showed variable staining, but always had a positive immunoreactions, provided the titer of the antiserum was sufficiently high. Striking differences were observed in metaplastic, atrophic and hyperplastic prostatic epithelium. The most intense reaction was observed in atrophic glands: it was much less intense in hyperplastic and normal epithelium and negative or slightly positive in metaplastic epithelium.

Ultrastructural and enzyme-histochemical studies of the prostate of the dog under the effect of estradiol

The prostate of 4 mature pure bred Beagles 12 months old was studied 3 weeks following a single i.m. injection of 1 mg estradiol/kg body weight by means of histochemistry (acid and alcaline phosphatase) and electron microscopy. Four 11 months old Beagles served as controls. Estradiol leads to a variable reaction of glandular epithelium. There is an atrophy of active secretory cells, probably due to an inhibition of the release of ICSH by the anterior pituitary lobe, that in turn leads to a deficiency of androgens. The residual secretory function is not sufficient for normal synthesis of secretory granules, recognizable through the decrease in electron density of secretory granules and the extensive loss of activity of acid phosphatase. Under physiologic conditions it corresponds in its localization to the amount of secretory granules lying in the apical portion of the cytoplasm. The basal reserve cells show an ambivalence. Normally under the predominant influence of androgen they do not show any metaplasia, but they differentiate into the secretorely active epithelial cell. Without stimulation by androgens, estradiol leads to a basal cell proliferation with squamous metaplasia particularly in the dorso-lateral lobes close to the urethra. The activity of alcaline phosphatase shows a minor decrease in the capillary endothelium under estradiol. With increasing maturation of the metaplastic squamous epithelium the activity of alcaline phosphatase increases in the upper cell layer.

Cytological findings in transrectal aspriation biopsy on hormone- and radio-treated carcinoma of the prostate

The study reports cytological findings in 63 cases of radio- and/or oestrogen-treated carcinoma of the prostate. The different effects of therapy on the tumor cells in the cytological smear are described and discussed. An evaluation of the results, depending on the type of therapy, showed, that radio-treated tumors, due to the rapid and strong sclerosis of connective tissue, were less suitable for aspiration biopsy than hormone-treated tumors. Further, we were able to show that the effect of therapy in well-differentiated tumors is better than in poorly differentiated tumors. Cytological examination of treated prostate carcinoma is a simple method, quickly carried out, repeatable several times, and of high diagnostic value. Aspiration biopsy is most of all indicated for follow-up of the less well-differentiated and the hormone-treated carcinomas.

Cyto- and histomorphogenesis of the prostate carcinoma. A comparative light- and electron-microscopic study

The fundamental histologic proliferation patterns of the prostate carcinoma are presented by the glandular and solid and/or cribriform structures. These were ultrastructurally analyzed from 28 carcinomas based on the cell forms in prostate carcinomas, which were already defined by electron microscope. These are characterized by their different cytoplasmic differentiation, whereby the singular cell types each represent a different functional state of a common tumor cell. The results indicate that the prostatic carcinoma develops morphologically in phases. The well-known growth patterns of the tumor are equivalent to its different states of development. In the first phase, a pattern develops out of a tumor stem cell (perhaps "primary atypical reserve cell"), which is either glandular or solid/cribriform, whereas this depends on the trend of the tumor cells to differentiate. The glandular structure possesses centrifugally proliferated glandular, often functionally deranged tumor cells, and shows signs of early stromal infiltration. The solid/cribriform pattern consists of centripetal proliferated, often less-differentiated tumor cells with or without lumen formation, and a peripheral layer of basal cells, whereby the idiopathic stroma architecture remains as it is. In the successive phase, stroma infiltration and destruction is distinctly marked durinaplastic" during tumor growth. Histologically, one often sees at this stage an "anaplastic" pattern; however, ultrastructurally its orign can be recognized as being glandular or solid/cribriform. The advanced stages of the tumor are furthermore characterized by a mixed cell pattern with all states of differentiation and by progressing tumor cell degeneration.

The cell proliferation of epithelial metaplasia in the prostate gland. An autoradiographic in vitro study

In 147 autoradiographically examined prostate biopsy cylinders 5.4% squamous metaplasia and 6.0% transitional metaplasia were diagnosed. The average labeling index of squamous metaplasia was 4.3% and corresponded with values from non-keratinizing squamous epithelium in other locations. The labeling index of the transitional cell metaplasia was, in contrary, almost 10 times lower with an average value of 0.29% and corresponded with the values well known for the urothelium of the urinary bladder. Higher labeling indices were observed in 2 cases but these had chronic prostatitis. The autoradiographic results are in good agreement with the ultrastructural findings in which the metaplastic squamous epithelium corresponds with normal squamous epithelium by which the cellular proliferation takes place only in the stratum basale. On the other hand, transitional metaplasia exhibits DNA-synthesizing cells in the superficial cell layers just like in the urothelium.