Gonadotropin-releasing hormone receptors in prostate tissue

OBJECTIVE: To perform an immunohistochemical analysis of gonadotropin-releasing hormone receptors (GnRH-Rs) in archival prostate tissue. STUDY DESIGN: Thirteen benign prostatic hyperplasia (BPH) specimens from open surgery, 48 radical prostatectomy specimens (30 surgery only and 18 neoadjuvant hormone treatment and surgery) and 14 prostate needle biopsies were examined. The avidin-biotin-peroxidase technique and monoclonal antibody A9E4 against the extracellular domain of GnRH-Rs were employed. Cases with > 5% immunoreactive cells (IR) were considered positive. RESULTS: The epitheliumfrom all 13 cases of BPH was immunoreactive. Most tumor cellsfrom biopsies were IR positive. Twenty-seven of 30 surgery-only specimens were IR positive vs. 8/18 in the surgery and neoadjuvant hormone treatment group. CONCLUSION: GnRH-Rs have been histochemically demonstrated in normal lutenizing hormone/follicle-stimulating hormone pituitary cells. In cell lines LN-CaP and DU-145, Gn-RH-R was identical to that of the pituitary. GnRH-Rs in the prostate can be quite easily assessed immunohistochemically in archival tissue samples, and hormone treatment significantly decreases the immunoreactivity of GnRH-Rs in prostate cancer tissue. This strongly suggests that GnRH agonists bind to BPH and prostate cancer cells.     

Do neuroendocrine cells in human prostate cancer express androgen receptor?

The presence of androgen receptors (AR) in neuroendocrine cells was investigated in benign tissue of 10 prostatectomy specimens, in 12 prostatic adenocarcinomas with focal neuroendocrine differentiation and in 1 case of a pure neuroendocrine small cell carcinoma of the prostate. Neuroendocrine cells were defined by their reactivity with an antibody to chromogranin A. Monoclonal antibody F39.4 directed against the amino-terminal domain of the AR molecule was used to detect AR. AR and chromogranin A were simultaneously visualized with a double immunofluorescence technique. The results indicate that chromogranin positive cells in both benign and malignant prostatic tissue lack detectable expression of AR. No effect of endocrine therapy was noted. These results are in agreement with the hypothesis that prostatic neuroendocrine tumour cells represent an androgen insensitive cell population, which incidentally may expand to replace the androgen-sensitive tumour cell population during androgen ablation therapy.     

Gleason grading of prostate carcinoma in needle biopsies vs. radical prostatectomy specimens

The Gleason grading system for prostatic carcinoma is the dominant method used around the world in research and in daily practice. It is based on glandular architecture. The grading system should be applied to all prostatic tissue samples, including needle core biopsies and radical prostatectomy specimens. Its prognostic value was tested in a large population with long-term follow-up that included use of survival as an end point. The Gleason grading system shows a reasonable degree of correlation between biopsy and radical prostatectomy specimens. Several sources of discrepancy between these 2 types of specimen have been identified. Further educational endeavors are needed to arrive at a greater consensus and accuracy in the use of the Gleason system.     

Immunohistochemical localization of protein gene product 9.5, ubiquitin, and neuropeptide Y immunoreactivities in epithelial and neuroendocrine cells from normal and hyperplastic human prostate.

This study was designed to investigate (a) the presence of protein gene product 9.5 (PGP 9.5), ubiquitin, and neuropeptide Y (NPY) in the neuroendocrine and secretory epithelium of the human normal prostate and its secretions, and (b) the changes in immunoreactivity to these proteins in men with benign prostatic hyperplasia. Western blotting and light microscopic immunohistochemistry techniques were used and the numerical density of immunoreactive neuroendocrine cells, and the volume fractions of immunostained secretory epithelium were evaluated. Western blotting revealed the presence of the three antigens in both tissue homogenates and prostate secretion. Some neuroendocrine cells immunoreacted to PGP 9.5 and NPY in all the prostate regions of control specimens. Ubiquitin immunoreactivity was detected in the nuclei from both basal cells and secretory epithelial cells. The cytoplasm of the secretory cells and the glandular lumen also showed immunostaining for the three proteins. The numerical densities of both PGP 9.5 and NPY neuroendocrine cells were lower in hyperplasia than in controls. No differences in the volume fraction occupied by epithelial immunostaining to both proteins was found between hyperplastic and control prostates. We concluded that (a) PGP 9.5 and NPY, but not ubiquitin, are common antigens in both neuroendocrine and secretory prostate cells, (b) the three immunoreactive proteins contribute to the prostate secretions, and (c) the secretion of ubiquitin is markedly diminished in the hyperplastic epithelium.(J Histochem Cytochem 48:1121-1130, 2000)     

Abberant methylation of p16, HIC1, N33 and GSTP1 genes in tumor epitelium and tumor-associated stromal cells of prostate cancer

The methylation status of four genes significant in prostate carcinogenesis p16, HIC1, N33 and GSTP1, were evaluated using quantitative methylationsensitive polymerase chain reaction. Tumor epithelia, tumor-associated stroma, normal epithelia, foci of PIN and benign prostate hyperplasia, and stroma adjacent to tumor tissues were isolated from whole-mount prostatectomy specimens of patients with localized prostate cancer by using laser capture microdissection. We found high levels of gene methylation in the tumor epithelium and tumor-associated stromal cells and some methylation in both hyperplastic epithelium and stromal cells in normal-appearing tissues located adjacent to tumors. Promoter methylation in the non-neoplastic cells of the prostate tumor microenvironment may play an important role in cancer development and progression. We examined the promoter methylation status of pl6, HIC1, N33 and GSTP1 in prostate biopsy fragments and prostate tissues after radical prostatectomy from patients with adenocarcinoma without laser capture microdissection. Methylation frequencies of all genes in tumor samples were considerably lower than frequencies in microdissected tumour samples (HIC1, 71 versus 89%; p16, 22 versus 78%; GSTP1, 32 versus 100%; N33, 20 versus 33%). The laser capture microdissection is required procedure in methylation studies taking into account multifocality and heterogenity of prostate cancer tissue.     

Histopathological changes induced by therapies in the benign prostate and prostate adenocarcinoma

The effect of androgen deprivation and other hormonal therapies, radiation therapy, thermal ablation therapies, chemotherapy, and other systemic treatments is evident in the histology of non-neoplastic and neoplastic human prostate gland. Androgen deprivation may be achieved with: a. orchidectomy, b. exogenous oestrogen administration, c. drugs with the capacity to deplete the hypothalamus of luteinizing hormone-releasing hormone, d. antiandrogens administration: drugs, which block the conversion of testosterone to its active form of 5-alpha dihydrotestosterone (i.e. finasteride, dutasteride), and drugs which block the androgen receptor on individual cells (i.e. flutamide). Androgen deprivation therapies cause atrophy of non-neoplastic and neoplastic prostatic epithelium, as the result of apoptosis, and are mainly used as a palliative measure in metastatic prostate cancer or as neoadjuvant or adjuvant treatment, in clinically localized prostate cancer. Morphological tumour regression may complicate the recognition and grading of treated carcinomas in radical prostatectomy specimens. Radiation therapy may be applied in the form of external beam, interstitial implantation (brachytherapy), or a combination, as a mainstay or adjuvant (external beam) treatment in localized prostate cancer. The primary effect is the damage of endothelial cells, which cause ischemia that leads to atrophy. The difficulty of post-radiation prostate needle biopsy interpretation includes the distinction of treatment effect in normal prostatic tissue from recurrent or residual tumour. Histological changes after thermal ablation mainly include lesions observed in prostatic infarcts due to periurethral coagulative type necrosis of variable volume. The correlation between the histopathological effects of the above therapies and their clinical significance is not absolutely clear.     

Expression of prostate specific membrane antigen (PSMA) in prostatic adenocarcinoma and prostatic intraepithelial neoplasia

The prostatic membrane antigen (PSMA) is a protein that is expressed in the prostatic epithelium. We studied the expression of PSMA in a series of 55 patients with different stages of prostate cancer and we compared the PSMA staining in prostate cancer cells, in high-grade prostatic intraepithelial neoplasia (PIN) and in histologically benign prostatic epithelium for the same specimen. For this purpose archival paraffin-embedded specimens were studied by immunohistochemistry with a monoclonal antibody 7E11-C5.3 against PSMA using the streptavidin-biotin method. The mean percentage of PSMA immunoreactivity was 56.67% in prostate cancer (CaP) cells, and 48.6% in PIN cells, which was significantly higher than benign-appearing prostatic epithelium (5.72%) (for each pair, p<0.001). PSMA expression was greater in CaP with a higher Gleason score (p=0.01), but no relationship was found with serum PSA value. We conclude that PSMA overexpression is detected in high-grade PIN and is associated with a higher Gleason score of prostate cancer. It is a potential marker for studying carcinogenesis and progression of prostate cancer.     

Laser-capture Microdissection of Human Prostatic Epithelium for RNA Analysis

The prostate gland contains a heterogeneous milieu of stromal, epithelial, neuroendocrine and immune cell types. Healthy prostate is comprised of fibromuscular stroma surrounding discrete epithelial-lined secretory lumens and a very small population of immune and neuroendocrine cells. In contrast, areas of prostate cancer have increased dysplastic luminal epithelium with greatly reduced or absent stromal population. Given the profound difference between stromal and epithelial cell types, it is imperative to separate the cell types for any type of downstream molecular analysis. Despite this knowledge, the bulk of gene expression studies compare benign prostate to cancer without micro-dissection, leading to stromal bias in the benign samples. Laser-capture micro-dissection (LCM) is an effective method to physically separate different cell types from a specimen section. The goal of this protocol is to show that RNA can be successfully isolated from LCM-collected human prostatic epithelium and used for downstream gene expression studies such as RT-qPCR and RNAseq.     

Localization of annexins I, II, IV and VII in whole prostate sections from radical prostatectomy patients

Annexins (ANXs) represent a family of calcium and phospholipid binding proteins that are involved in several physiological processes e.g. signal transduction, cellular differentiation and proliferation. Since they are known to be dysregulated in a variety of cancers we investigated the immunolocalization of ANXs in whole prostate sections containing benign prostatic epithelium (BPE), benign prostatic hyperplasia (BPH), prostatic intraepithelial neoplasia (PIN) and prostate cancer (PCa) in order to evaluate their possible role during tumorigenesis. Samples were obtained from 28 patients undergoing radical prostatectomy. Gross sections of whole prostates were examined immunohistochemically for the distribution of ANX I, II, IV and VII. In BPE all ANXs were localized to the cell membranes and the cytoplasm of all gland cells. In BPH the immunoreactivity of ANX I and II was restricted to the basal cells of glands and expression pattern of ANX IV and VII was similar to BPE. In PIN only basal cells expressed ANX II. In PCa ANX II immunoreactivity was absent and weak ANX I and ANX IV immunoreactivity was restricted to the cytoplasm of tumor cells. ANX VII immunoreactivity was seen in some but not all tumor cells. Since ANX IV and VII expression did not show significant changes in PCa compared to non-neoplastic tissue and PIN an essential role during prostate tumourigenesis seems unlikely. In contrast, as progression from PIN to PCa is characterized by a reduction of ANX I and II this suggests that downregulation of these proteins could represent an important event in prostate carcinogenesis.     

Cancer de la prostate : les marqueurs biologiques

Normal prostate cells and prostate cancer cells produce prostate-specific antigen (PSA): thus, it is frequently increased in non-malignant conditions such as prostatitis and benign prostatic hyperplasia. Indeed, PSA is an excellent biomarker to monitor disease progression. The low diagnostic specificity of PSA leads to many false-positive and a large number of biopsies. These well-recognized limitations of PSA suggest that new prostate cancer biomarkers could play a useful role in reducing the number of unnecessary biopsies.     

Relationship between the prostatic tissue components and natural history of benign prostatic hyperplasia

OBJECTIVE: Few reports have been published on the relationship between prostatic tissue components and the natural history of benign prostatic hyperplasia (BPH). The present study was undertaken to evaluate this relationship. STUDY DESIGN: Forty-nine patients with BPH who underwent suprapubic prostatectomy were studied. Six infant prostates and 10 non-BPH specimens were obtained from autopsy. Specimens were stained with antibodies to alpha-smooth muscle actin, and the mean ratio of the stroma was determined with computer image analysis. Stromal ratios were evaluated according to resected prostate weight and age. RESULTS: The stroma comprised 82.6 +/- 8.4% of the prostate area at 0-1 year of age and 43.7 +/- 5.1% at 15-28 years of age. In BPH, the stromal proportion increased to 55.9 +/- 10.2%, but decreased with increases in prostate weight and/or age. CONCLUSION: The stromal component increased in patients with BPH and decreased with increased prostate weight and/or age, comprising approximately 42-47% of the prostate area, as in the non-BPH prostate, indicating a balance in prostatic tissue components in both patients with BPH and the non-BPH prostate.     

Nuclear volume estimates in prostatic atypical adenomatous hyperplasia

OBJECTIVE: To investigate nuclear volume estimates by the point-sampled intercepts method in atypical adenomatous hyperplasia (AAH) as compared with nodular hyperplasia and well-differentiated prostatic adenocarcinoma. STUDY DESIGN: The study group consisted of 27 formalin-fixed, paraffin-embedded, whole-mounted radical prostatectomy specimens that contained foci of nodular hyperplasia, atypical adenomatous hyperplasia and well-differentiated adenocarcinoma (Gleason pattern 1 and 2). Representative sections were selected for stereologic estimation of volume-weighted mean nuclear volume by the point-sampled intercepts method. On each focus, an average of five fields of vision were systematically chosen. RESULTS: The quantitative results indicate an increase in nuclear volume from nodular hyperplasia (209 +/- 65 micron 3) to AAH (237 +/- 85 micron 3) and prostate adenocarcinoma (436 +/- 106 micron 3). Significant differences were found (F = 39.0, P < .001) with two group comparisons (Scheffe's procedure) between prostate cancer and AAH (P < .001) or nodular hyperplasia (P < .001). The difference between AAH and benign hyperplasia was not signifcant. CONCLUSION: The results indicate that three-dimensional estimates of the nuclear size discriminate AAH and nodular hyperplasia from well-differentiated prostate adenocarcinoma. These findings suggest that AAH is probably a histologic variant of benign prostatic hyperplasia the exact relationship of which to prostatic adenocarcinoma remains to be determined.     

Computerized microscopic analysis of prostatic fine needle aspirates. Comparison with breast aspirates

Computerized image analysis was employed to analyze fine needle aspiration smears of the prostate and breast using both high-resolution images of individual cells and medium-resolution images of scenes and clusters (contextual analysis). A linear discriminant analysis was used to demonstrate the computer's ability to discriminate between benign and malignant categories for both types of tissue. Correct classification as benign or malignant using contextual analysis was achieved in 22 of 26 prostatic aspirates and in 15 of 18 breast aspirates, as determined by comparison with histology. The addition of high-resolution single-cell analysis resulted in correct classification of 24 of 26 prostatic aspirates and all breast aspirates. For virtually all features, the distinction between benign and malignant was more subtle for prostatic than for breast tissue. The data indicate that contextual analysis may be less effective as an adjunct to high-resolution single-cell microscopy of prostatic specimens than it is for breast specimens.     

An unusual case of retrovesical ectopic prostate tissue accompanied by primary prostate cancer

ABSTRACT: We report an unusual case of retrovesical ectopic prostate tissue in a 73-year-old man with primary prostate cancer. The man's prostate-specific antigen was 24.66 ng/ml. Transabdominal ultrasonography, pelvic computed tomography and pelvic magnetic resonance imaging demonstrated a heterogeneous 8.5 x 8.0 x 7.0 cm mass in contact with the posterior wall of the urinary bladder. The patient underwent a retropubic radical prostatectomy and resection of the tumor. Pathological examination of the prostate revealed a prostatic adenocarcinoma, Gleason score of 4 + 5 = 9, and the retrovesical tumor was confirmed to be a benign prostate tissue.     

Interferon-gamma and its functional receptors overexpression in benign prostatic hyperplasia and prostatic carcinoma: parallelism with c-myc and p53 expression

The therapeutic potential of IFN-gamma in prostatic cancer has been documented in several reports, although no immunohistochemical studies of this factor and its receptors in the prostate have been reported. The aim of the present study was to investigate the expression of IFN-gamma and its receptor components (IFN-gamma-Ralpha and IFN-gamma-Rbeta) in normal prostate, benign prostatic hyperplasia (BPH) and prostatic cancer (PC), as well as the possible relationship between this factor and the products of the p53 gene (the wild and mutant forms) and the oncogene c-myc, by means of immunochemical techniques (Western blot, ELISA, and quantification of immunostaining in histological sections). In normal prostate, IFN-gamma and its two receptors were expressed in the basal cells of the epithelium and some stromal cells. In BPH specimens, immunostaining of basal epithelial cells was significantly increased for IFN-gamma and its a receptor, whereas stromal cell immunostaining was significantly increased for IFN-gamma and its b receptor. In addition, columnar epithelial cells immunostained for IFNbeta-Rbeta. PC specimens differed from BPH specimens in the significantly increased immunostaining of epithelial cells for IFN-gamma and its two receptors, and the immunostaining of columnar epithelial cells for IFN-gamma-Ralpha. Immunodetection of wild-p53 was weak and limited to some stromal cells in the three types of specimens. Immunostainings for both mutant-p53 and c-myc were negative in normal prostate, and positive in the epithelium and stromal cells of both BPH and PC specimens. Immunostaining intensity in PC was significantly higher than in BPH. These observations suggest that the expression of both mutant-p53 and c-myc, together with other factors, might be involved in the development of prostatic hyperplasia and neoplasia, while the increased expression of IFN-gamma and its receptors could be regarded as an attempt, although insufficient, to inhibit the uncontrolled cell proliferation.     

New approaches to the treatment of advanced prostate cancer

Several presentations by attendees of the 11th International Prostate Cancer Update addressed recent advances in prostate cancer treatment. A study that examined whether a relationship exists between neuroendocrine (NE) cell differentiation and hormone-refractory prostate cancer (HRPC) concluded that the appearance of NE cells in prostatic carcinoma is an important phenomenon in the development of HRPC. Exisuland, a selective apoptotic antineoplastic drug, was compared to placebo in a recent study and was found to significantly inhibit the increase of prostate-specific antigen in patients who had undergone radical prostatectomy. A new dosing regimen for flutamide (500 mg daily) was found to have no significant differences from the currently recommended dose (250 mg every 8 hours); the new, single daily dose could meet with greater compliance and would reduce drug cost by 30%. The antiproliferative effect of vitamin D on prostatic carcinoma cells was discussed, along with the possible role of vitamin D supplementation during prostate cancer treatment. Finally, a presentation on hospice care acknowledged that referral for such care is unfortunately at times delayed by physicians, patients, and patients' families, leaving insufficient time for all the benefits of that stage of care to be realized.     

Transforming growth factor beta 1 and androgen receptors in prostate neoplasia

OBJECTIVE: To investigate the interplay between transforming growth factor (TGF) beta 1, androgen receptors and stromal-epithelial interactions in benign prostatic hyperplasia (BPH), prostate intraepithelial neoplasia (PIN) and prostate carcinoma areas of prostate neoplasia. STUDY DESIGN: In this immunohistochemical study we investigated staining patterns and then determined the correlation between TGF-beta 1 expression and androgen receptor status in the epithelium and stroma of 60 paraffin-embedded tissues from radical prostatectomies. RESULTS: Staining patterns differed in the epithelium and stroma of tumor and peritumor prostatic tissue. TGF-beta 1 immunostaining (H-scores) in the epithelium and stroma increased significantly from BPH to PIN and from BPH to prostate carcinoma in the epithelium (P < .05), whereas androgen receptor (AR) immunoreactivity significantly (P < .05) increased from BPH to PIN to prostatic carcinoma in epithelium and stroma. TGF-beta 1 did not correlate with histologic grade of differentiation, whereas AR proteins were more strongly expressed in Gleason score 5 and 6 than score 7 tumors (P < .05). Nonlinear regression showed a significant correlation (P < .01) between TGF-beta 1 and AR expression only in the stromal compartment of PIN. CONCLUSION: These findings argue in favor of an interaction between TGF-beta 1 and AR in the early stages of prostate carcinogenesis and suggest that TGF-beta 1 plays a central role in stromal-epithelial interactions during the early stages of malignant transformation.     

Differential vitamin D 24-hydroxylase/CYP24A1 gene promoter methylation in endothelium from benign and malignant human prostate

Epigenetic alterations occur in tumor-associated vessels in the tumor microenvironment. Methylation of the CYP24A1 gene promoter differs in endothelial cells isolated from tumors and non-tumor microenvironments in mice. The epigenetic makeup of endothelial cells of human tumor-associated vasculature is unknown due to difficulty of isolating endothelial cells populations from a heterogeneous tissue microenvironment. To ascertain CYP24A1 promoter methylation in tumor-associated endothelium, we utilized laser microdissection guided by CD31 immunohistochemistry to procure endothelial cells from human prostate tumor specimens. Prostate tissues were obtained following robotic radical prostatectomy from men with clinically localized prostate cancer. Adjacent histologically benign prostate tissues were used to compare endothelium from benign versus tumor microenvironments. Sodium bisulfite sequencing of CYP24A1 promoter region showed that the average CYP24A1 promoter methylation in the endothelium was 20% from the tumor microenvironment compared with 8.2% in the benign microenvironment (p < 0.05). A 2-fold to 17-fold increase in CYP24A1 promoter methylation was observed in the prostate tumor endothelium compared with the matched benign prostate endothelium in four patient samples, while CYP24A1 promoter methylation remained unchanged in two patient samples. In addition, there is no correlation of the level of CYP24A1 promoter methylation in prostate tumor-associated endothelium with that of epithelium/stroma. This study demonstrates that the CYP24A1 promoter is methylated in tumor-associated endothelium, indicating that epigenetic alterations in CYP24A1 may play a role in determining the phenotype of tumor-associated vasculature in the prostate tumor microenvironment.Key words: CYP24A1, DNA methylation, human prostate cancer, tumor endothelium, laser microdissection     

Differential vitamin D 24-hydroxylase/CYP24A1 gene promoter methylation in endothelium from benign and malignant human prostate

Epigenetic alterations occur in tumor-associated vessels in the tumor microenvironment. Methylation of the CYP24A1 gene promoter differs in endothelial cells isolated from tumors and non-tumor microenvironments in mice. The epigenetic makeup of endothelial cells of human tumor-associated vasculature is unknown due to difficulty of isolating endothelial cells populations from a heterogeneous tissue microenvironment. To ascertain CYP24A1 promoter methylation in tumor-associated endothelium, we utilized laser microdissection guided by CD31 immunohistochemistry to procure endothelial cells from human prostate tumor specimens. Prostate tissues were obtained following robotic radical prostatectomy from men with clinically localized prostate cancer. Adjacent histologically benign prostate tissues were used to compare endothelium from benign versus tumor microenvironments. Sodium bisulfite sequencing of CYP24A1 promoter region showed that the average CYP24A1 promoter methylation in the endothelium was 20% from the tumor microenvironment compared with 8.2% in the benign microenvironment (p&lt;0.05). A 2-fold to 17-fold increase in CYP24A1 promoter methylation was observed in the prostate tumor endothelium compared with the matched benign prostate endothelium in four patient samples, while CYP24A1 remained unchanged in two patient sample. In addition, there is no correlation of the level of CYP24A1 promoter methylation in prostate tumor-associated endothelium with that of epithelium/stroma. This study demonstrates that the CYP24A1 promoter is methylated in tumor-associated endothelium, indicating that epigenetic alterations in CYP24A1 may play a role in determining the phenotype of tumor-associated vasculature in the prostate tumor microenvironment.