High grade prostatic intraepithelial neoplasia. The most likely precursor of prostate cancer

Conditional gene regulation models demonstrate a pro-proliferative role for growth hormone receptor in prostate cancer

BACKGROUND

Humans with inactivating mutations in growth hormone receptor (GHR) have lower rates of cancer, including prostate cancer. Similarly, mice with inactivating Ghr mutations are protected from prostatic intraepithelial neoplasia in the C3(1)/TAg prostate cancer model. However, gaps in clinical relevance in those models persist. The current study addresses these gaps and the ongoing role of Ghr in prostate cancer using loss-of-function and gain-of-function models.

METHODS

Conditional Ghr inactivation was achieved in the C3(1)/TAg model by employing a tamoxifen-inducible Cre and a prostate-specific Cre. In parallel, a transgenic GH antagonist was also used. Pathology, proliferation, and gene expression of 6-month old mouse prostates were assessed. Analysis of The Cancer Genome Atlas data was conducted to identify GHR overexpression in a subset of human prostate cancers. Ghr overexpression was modeled in PTEN-P2 and TRAMP-C2 mouse prostate cancer cells using stable transfectants. The growth, proliferation, and gene expression effects of Ghr overexpression was assessed in vitro and in vivo.

RESULTS

Loss-of-function for Ghr globally or in prostatic epithelial cells reduced proliferation and stratification of the prostatic epithelium in the C3(1)/TAg model. Genes and gene sets involved in the immune system and tumorigenesis, for example, were dysregulated upon global Ghr disruption. Analysis of The Cancer Genome Atlas revealed higher GHR expression in human prostate cancers with ERG-fusion genes or ETV1-fusion genes. Modeling the GHR overexpression observed in these human prostate cancers by overexpressing Ghr in mouse prostate cancer cells with mutant Pten or T-antigen driver genes increased proliferation of prostate cancer cells in vitro and in vivo. Ghr overexpression regulated the expression of multiple genes oppositely to Ghr loss-of-function models.

CONCLUSIONS

Loss-of-function and gain-of-function Ghr models, including prostatic epithelial cell specific alterations in Ghr, altered proliferation, and gene expression. These data suggest that changes in GHR activity in human prostatic epithelial cells play a role in proliferation and gene regulation in prostate cancer, suggesting the potential for disrupting GH signaling, for example by the FDA approved GH antagonist pegvisomant, may be beneficial in treating prostate cancer.

Plasma Polyamine Biomarker Panels: Agmatine in Support of Prostate Cancer Diagnosis

Prostate cancer is the most frequent malignant tumour among males (19%), often clinically silent and of difficult prognosis. Although several studies have highlighted the diagnostic and prognostic role of circulating biomarkers, such as PSA, their measurement does not necessarily allow the detection of the disease. Within this context, many authors suggest that the evaluation of circulating polyamines could represent a valuable tool, although several analytical problems still counteract their clinical practice. In particular, agmatine seems particularly intriguing, being a potential inhibitor of polyamines commonly derived from arginine. The aim of the present work was to evaluate the potential role of agmatine as a suitable biomarker for the identification of different classes of patients with prostate cancer (PC). For this reason, three groups of human patients—benign prostatic hyperplasia (BPH), precancerous lesion (PL), and prostate cancer (PC)—were recruited from a cohort of patients with suspected prostate cancer (n = 170), and obtained plasma was tested using the LC-HRMS method. Statistics on the receiver operating characteristics curve (ROC), and multivariate analysis were used to examine the predictive value of markers for discrimination among the three patient groups. Statistical analysis models revealed good discrimination using polyamine levels to distinguish the three classes of patients. AUC above 0.8, sensitivity ranging from 67% to 89%, specificity ranging from 74% to 89% and accuracy from 73% to 86%, considering the validation set, were achieved. Agmatine plasma levels were measured in PC (39.9 ± 12.06 ng/mL), BPH (77.62 ± 15.05 ng/mL), and PL (53.31 ± 15.27 ng/mL) patients. ROC analysis of the agmatine panel showed an AUC of 0.959 and p ≤ 0.001. These results could represent a future tool able to discriminate patients belonging to the three different clinical groups.

Hormone-Refractory Prostate Cancer in the Lobund-Wistar Rat

Research on cancer prevention and therapy must focus on the refractory disease, the fatal end-stage of cancer that develops in patients with organ-related solid tumors. Refractory cancers develop spontaneously in advanced-stage tumors or in relapsed cases after failed therapy. Because neither prevention nor therapy is currently feasible, refractory cancer is a major impediment to survival. There is a great need for an animal model of prostate cancer (PC), one that develops cancer from initial premalignant to the terminal refractory stages. We describe here a model of hormone-refractory prostate cancer (HRPC) that develops spontaneously through two stages by endogenous mechanisms in the Lobund-Wistar (LW) rat. The early premalignant, testosterone (T)-dependent stage is promoted by high levels of endogenous T, and up to age 12 months is reversible by T deprivation; without this intervention, the tumorigenic process progresses to the refractory stage, which is highly aggressive and does not respond to T deprivation or to a wide range of therapies. Initial refractory tumors are palpable at approximately 18 months of age. As they continue to grow, the tumors express characteristics seen in refractory cancers in humans (i.e., hypoxia, expression of hypoxia-inducible factors, and metastasis). Chemically induced HRPCs in LW rats manifest the same two developmental stages, but with shorter latency periods. A transplantable, metastasizing cell line (PAID) was derived from a germfree LW rat with advanced-stage cancer. Both spontaneous and chemically induced autochthonous HRPC model systems serve as outstanding models for studies on the prevention and therapy of refractory cancer.

A retrospective analysis of 111 canine prostatic samples: histopathological findings and classification

The purpose of this retrospective study is to evaluate the frequency and further characterize the pathological features of common and uncommon histological lesions in 111 canine prostatic samples. Benign prostatic hyperplasia, suppurative and non-suppurative prostatitis, and prostate cancer were observed individually or in combination in 45, 11, 68 and 50 samples, respectively. Six growth patterns of prostatic carcinoma were differentiated: papillary, cribriform, solid, small acinar/ductal, signet ring, mucinous. In a few cases, perineurial invasion and collagenous micronodules were observed. Lesions considered preneoplastic in men, such as high-grade prostatic intraepithelial neoplasia (HGPIN) and prostatic inflammatory atrophy (PIA), were observed in 27 and 21 histological samples, respectively. This study represents a detailed characterization of the different histological subtypes of canine prostate cancer. The awareness of the unusual patterns might be critical in avoiding diagnostic misinterpretation. The high prevalence of PIA and HGPIN underlines the reasonable chance of their detection in routine biopsy specimens.

Computer-assisted three-dimensional analysis of multifocal/multicentric prostate cancer

In order to study multiple contiguous prostate cancer lesions, we constructed computer-assisted, three-dimensional models of multifocal prostate cancer specimens obtained by radical prostatectomy. We then examined the genetic heterogeneity among the specimens by DNA microarray analysis. Cancer foci with high Gleason patterns were found to occur de novo, whereas those with low Gleason patterns occurred contiguously with cancers of low Gleason patterns. Three-dimensional analysis showed that distinct, noncontiguous cancerous foci were genetically independent and multicentric. In contrast some contiguous multifocal lesions had the same genetic origin.

Chemopreventive effect of quercetin in MNU and testosterone induced prostate cancer of Sprague-Dawley rats

Prostate cancer becomes an ideal target for chemoprevention because of its high incidence and extended natural history. The consumption of quercetin (plant flavonoid) in diet is associated with decreased risk of disease and many cancers but then this was not elucidated in prostate malignancy. Hence, a study in which the male Sprague-Dawley rats were induced prostate cancer by hormone (testosterone) and carcinogen (MNU) and simultaneously supplemented with quercetin (200 mg/Kg body weight) thrice a week, was conducted. After the treatment period, rats were killed; ventral and dorsolateral lobes of the prostate were dissected. Histology and oxidative stress markers LPO, H2O2, and antioxidant GSH level were measured in both lobes. The lipid peroxidation, H2O2, in (MNU+T) treated rats were increased and GSH level was decreased, whereas simultaneous quercetin-treated rats reverted back to normal level in both ventral and dorsolateral regions. The different patterns of PIN were observed with associated hyperplasia and dysplasia; changes in these regions and the occurrence of this lesion were reduced in simultaneous quercetin-treated rats. The study concluded that dietary quercetin prevented MNU + T-induced prostate carcinogenesis on both ventral and dorsolateral lobes of Sprague-Dawley rats.

Expression of p 16 protein in prostatic adenocarcinomas, intraepithelial neoplasia, and benign/hyperplastic glands

The tumor suppressor gene CDKN2/MTSI(p16(INK4)) may be inactivated by point mutations, deletions, or methylation in many tumor types. In prostate cancer, a very low frequency of point mutations has been reported, but deletions of 9p21 and inactivation by methylation are observed more frequently. The purpose of this study was to assess the expression pattern of the CDKN2 protein product p 16 in a series of 104 prostatic adenocarcinomas treated by radical prostatectomy, using immunohistochemical detection on archival, paraffin-embedded material. Nuclear staining was completely absent in 13 (13%) of 104 cases, whereas cytoplasmic staining was found in 99 (95%) of 104 carcinomas. Significant differences were found when comparing the staining intensity of carcinomas and coexisting prostatic intraepithelial neoplasia (PIN) with benign/hyperplastic glands. In 86 (95%) of 91 cases the overall staining intensity of carcinomas was stronger than the reactivity in benign/hyperplastic glands, which were most often weakly stained. In 71 (95%) of 75 cases the staining intensity of PIN was stronger than in benign/hyperplastic glands, a contrast also observed within single glands. However, p16 immunostaining in carcinomas was not prognostically important and it was not associated with standard clinicopathologic parameters. Our results support that CDKN2/plb is inactivated in only a small proportion of localized prostate cancers. The increased p16 staining of carcinomas/PIN in comparison with benign/hyperplastic glands suggests that p 16 protein may be involved in early stages of prostate tumorigenesis by mechanisms other than CDKN2/p16 gene inactivation, and the possibility of using p(16) immunostaining as a marker for PIN is discussed.

Óxido nítrico, GSTP-1 e p53: qual o papel desses biomarcadores nas lesões prostáticas do cão?

Confeccionou-se um microarranjo de tecido (TMA) com 146 amostras de lesões prostáticas caninas. Este continha 17,2% de hiperplasia prostática benigna (HPB), 32,4% de atrofia inflamatória proliferativa (PIA), 2,6% de prostatite, 8,6% de focos de neoplasia intraepitelial prostática (PIN), 29,1% de carcinomas e 9,3% de próstatas normais. Cortes histológicos sequenciais foram feitos e utilizados para reação de imunoistoquímica com os anticorpos primários anti-p-53, anti-NOS-2 e anti-GSTP. Avaliou-se de cada core o escore de células marcadas para cada anticorpo utilizado. Os resultados foram tabulados por grupo diagnóstico e submetidos ao teste Tuckey. Os carcinomas prostáticos do cão e a PIA apresentaram maior número de amostras (41) com mais de 75% das células positivas para NOS-2, demonstrando a influência do estresse oxidativo no desenvolvimento dessas lesões. As próstatas normais e as afecções desta glândula, HPB, PIA, PIN, prostatite e carcinoma, expressaram a proteína GSTP-1, o que conferiu proteção ao tecido prostático canino a danos oxidativos. A proteína p53 estava presente em todas as amostras estudadas, incluindo o tecido prostático normal, porém as lesões prostáticas apresentaram maior número de amostras com escores mais elevados de marcação (escores três e quatro), presente em 95% dos focos de PIA e carcinoma. Concluiu-se que o aumento de expressão de óxido nítrico nas lesões prostáticas no cão e a expressão de GSTP-1 podem ter protegido o tecido prostático canino e que a expressão de p53 foi positiva e uniforme nas próstatas normais e com lesões hiperplásicas e displásicas.

Metastasis suppressors in human benign prostate, intraepithelial neoplasia, and invasive cancer: their prospects as therapeutic agents

Despite advances in diagnosis and treatment of prostate cancer, development of metastases remains a major clinical challenge. Research efforts are dedicated to overcome this problem by understanding the molecular basis of the transition from benign cells to prostatic intraepithelial neoplasia (PIN), localized carcinoma, and metastatic cancer. Identification of proteins that inhibit dissemination of cancer cells will provide new perspectives to define novel therapeutics. Development of antimetastatic drugs that trigger or mimic the effect of metastasis suppressors represents new therapeutic approaches to improve patient survival. This review focuses on different biochemical and cellular functions of metastasis suppressors known to play a role in prostate carcinogenesis and progression. Ten putative metastasis suppressors implicated in prostate cancer are discussed. CD44s is decreased in both PIN and cancer; Drg-1, E-cadherin, KAI-1, RKIP, and SSeCKS show similar expression between benign epithelia and PIN, but are downregulated in invasive cancer; whereas, maspin, MKK4, Nm23 and PTEN are upregulated in PIN and downregulated in cancer. Moreover, the potential role of microRNA in prostate cancer progression, the understanding of the cellular distribution and localization of metastasis suppressors, their mechanism of action, their effect on prostate invasion and metastasis, and their potential use as therapeutics are addressed.

Genomic biomarkers for molecular imaging: predicting the future

Over the past few decades, great strides have been made in anatomical imaging of disease that has led to their diagnosis with minimal invasion. Despite these advances, diseases such as cancer continue to take one human life every minute in the United States. Complimentary approaches that pertain directly to the genesis of the disease might contribute to its early diagnosis and subsequent management. In cancer, an array of molecular abnormalities leading to the modulations in expression of key proteins important in the cellular signaling pathways and cell proliferation has been identified. These specific disease fingerprints, biomarkers, are overexpressed on malignant cell surfaces or within the cytoplasm, and they provide unique targets that are promising for improving cancer diagnosis and therapy. We and others have designed, synthesized, and evaluated some novel probes specific for those oncogenes and oncogene product biomarkers for PET and SPECT molecular imaging of certain types of cancers. This article briefly describes this approach and gives specific examples that depict the ability of molecular imaging to detect occult lesions not detectable by current scintigraphic approaches. The article also outlines a few examples predicting other possible applications of targeting such specific probes not yet used.

Disruption of growth hormone signaling retards prostate carcinogenesis in the Probasin/TAg rat

We asked whether down-regulation of GH signaling could block carcinogenesis in the Probasin/TAg rat, a model of aggressive prostate cancer. The Spontaneous Dwarf rat, which lacks GH due to a mutation (dr) in its GH gene, was crossed with the Probasin/TAg rat, which develops prostate carcinomas at 100% incidence by 15 wk of age. Progeny were heterozygous for the TAg oncogene and homozygous for either the wild-type GH gene (TAg/Gh(+/+)) or the dr mutation (TAg/Gh(dr/dr)). Prostate tumor incidence and burden were significantly reduced, and tumor latency was delayed in TAg/Gh(dr/dr) rats relative to TAg/Gh(+/+) controls. At 25 wk of age, loss of GH resulted in a 20 and 80% decrease in the area of microinvasive carcinoma in the dorsal and lateral lobes, respectively. By 52 wk of age, invasive prostate adenocarcinomas were observed in all TAg/Gh(+/+) rats, whereas the majority of TAg/Gh(dr/dr) did not develop invasive tumors. Suppression of carcinogenesis could not be attributed to alterations in prostate expression of TAg or androgen receptor or changes in serum testosterone levels. As carcinogenesis progressed in TAg/Gh(+/+) rats, prostate GHR mRNA and protein expression increased significantly, but prostate IGF-I receptor mRNA and protein levels dropped. Furthermore, serum IGF-I and prostate IGF-I levels did not change significantly over the course of carcinogenesis. These findings suggest that GH plays a dominant role in progression from latent to malignant prostate cancer driven by the powerful probasin/TAg fusion gene in rats and suggest that GH antagonists may be effective at treating human prostate cancer.

The ABCA5 protein: a urine diagnostic marker for prostatic intraepithelial neoplasia

PURPOSE

To develop a urine diagnostic test for preneoplastic intraepithelial neoplasia of the prostate.

EXPERIMENTAL DESIGN

We have used a DNA-binding assay and electrophoretic mobility shift assays (EMSA) to screen for novel duplexed DNA-binding sequences, which bind protein(s) overexpressed in crude protein extracts from high-grade prostatic intraepithelial neoplasia (HGPIN). EMSAs, immunohistochemistry, and ELISAs were used to measure expression of the ABCA5 protein identified as a specific marker in prostate tissue and patient urine.

RESULTS

Following screening of 4,096 sequences, an 8-bp dsDNA sequence (i.e., TCCAGCGA) was identified, which binds the ABCA5 protein, a member of the ATP-binding cassette multidrug resistant family. EMSAs showed that ABCA5 was overexpressed in HGPIN tissue (n=11/11) and in the urine of patients with HGPIN (n=18/18) but was not expressed in prostate cancer, benign prostatic hyperplasia, or stroma. Immunohistochemistry indicated that ABCA5 was overexpressed in foci of intermediate basal cells in normal glands and in HGPIN. ABCA5 was faintly expressed in prostate cancer glands. ELISAs showed in 'blinded studies' that ABCA5 was a highly sensitive (>98% sensitivity) urine diagnostic marker for HGPIN in biopsy-positive patients (n=107) at a 'cutoff' of 25 ng/mL. ABCA5 was present at very low levels (i.e., <25 ng/mL) in the urine of patients diagnosed with benign prostatic hyperplasia (n=79) or prostatitis or kidney and bladder cancer (>86% specificity).

CONCLUSIONS

The data indicate that ABCA5 might be a specific urine marker for diagnosis of patients with HGPIN.

Toremifene for the prevention of prostate cancer in men with high grade prostatic intraepithelial neoplasia: results of a double-blind, placebo controlled, phase IIB clinical trial

PURPOSE

A randomized, double-blind, dose finding, placebo controlled, parallel group clinical study was done to determine the incidence of prostate cancer in men with high grade prostatic intraepithelial neoplasia treated with toremifene.

MATERIALS AND METHODS

A total of 514 patients with high grade prostatic intraepithelial neoplasia and no evidence of prostate cancer on screening biopsy were randomized to 20, 40 or 60 mg toremifene, or placebo daily for 12 months. Patients underwent re-biopsy at 6 and 12 months.

RESULTS

The number of evaluable patients, that is those with 1 on study biopsy who were compliant, was 447. The cumulative risk of prostate cancer was decreased in patients on 20 mg toremifene compared with placebo (24.4% vs 31.2%, p <0.05). The annualized rate of prevention was 6.8 cancers per 100 men treated. In patients with no biopsy evidence of cancer at baseline and 6 months, the 12-month incidence of prostate cancer was decreased by 48.2% with 20 mg toremifene compared with placebo (9.1% vs 17.4%, p <0.05). The 20 mg dose was most effective but cumulative and 12-month incidences of prostate cancer were lower for each toremifene dose vs placebo with a cumulative risk of 29.2% and 28.1%, and a 12-month incidence of 14.3% and 13.0% for 40 and 60 mg, respectively. Gleason scores were similar across treatments. The overall incidence of drug related and serious adverse events did not differ between any of the toremifene groups and the placebo group.

CONCLUSIONS

Toremifene decreased the incidence of prostate cancer by 1 year and had a tolerability profile comparable to that of placebo in a high risk population.

Histopathology reporting of prostate needle biopsies. 2005 update

This report reviews the diagnostic and prognostic importance of the pathologic findings in prostate needle biopsies. The morphological findings of the needle biopsy may be placed into one of the following five categories: prostate cancer, atypical small acinar proliferation, high-grade prostatic intraepithelial neoplasia, inflammation, and benign prostatic tissue. While the prime goal of the biopsy is to diagnose prostatic adenocarcinoma, once carcinoma is detected, further descriptive information regarding the type, amount of cancer, and grade forms the cornerstone for contemporary management of the patient and for assessment of the potential for local cure and the risk for distant metastasis. The information provided in the needle biopsy report regarding the attributes of carcinoma is used depending on the individual patient's medical condition and preference and on the treating physician's evaluation to determine whether any form of treatment is indicated and, if so, the type of therapy.

The significance of the P504S expression pattern of high-grade prostatic intraepithelial neoplasia (HGPIN) with and without adenocarcinoma of the prostate in biopsy and radical prostatectomy specimens

Diagnosis of prostatic adenocarcinoma is usually not difficult in biopsy specimens. Problems may occur in biopsy specimens, containing only a few suspicious lesions. Recently, P504S has been tested as a new marker for prostatic carcinoma. When over-expressed in atypical glands without basal cells, it establishes the diagnosis of prostatic carcinoma. We analysed the staining intensity of P504S in 208 biopsy specimens from prostates (1) with adenocarcinoma (n=132), (2) with high-grade prostatic intraepithelial neoplasia (HGPIN) with adenocarcinoma (n=36), (3) with HGPIN alone (n=40) and in radical prostatectomy specimens with HGPIN adjacent to (n=54) or distant from adenocarcinoma (n=64). P504S expression was negative to weakly positive in biopsy specimens showing HGPIN without carcinoma and weakly positive in radical prostatectomy specimens revealing HGPIN distant from adenocarcinoma. In biopsy specimens with a combination of HGPIN and adenocarcinoma and in radical prostatectomy specimens with HGPIN adjacent to adenocarcinoma, P504S was strongly expressed. The same findings were made in radical prostatectomy specimens containing adenocarcinoma and HGPIN adjacent to or distant from adenocarcinoma and in preoperative biopsies revealing adenocarcinoma and HGPIN. These results suggest that moderate to strong P504S expression in HGPIN of biopsy specimens is indicative of an associated adenocarcinoma and may be helpful in the choice of therapy.

Chemoprevention of prostate cancer by cholecalciferol (vitamin D3): 25-hydroxylase (CYP27A1) in human prostate epithelial cells

The 20-30 year latency period for prostate cancer provides an important opportunity to prevent the development of invasive cancer. A logical approach for chemoprevention to reduce incidence is to identify agents, such as, vitamin D, which can inhibit cell proliferation and induce differentiation, are safe, and readily available to the public at low cost. Epidemiological evidence suggests that vitamin D deficiency is associated with increased risk for prostate cancer. We examined the ability and mechanisms of action of cholecalciferol (vitamin D(3)), a precursor of the most biologically active hormone calcitriol, to block or reverse premalignant changes. The immortalized, non-tumorigenic, RWPE-1 human prostate epithelial cell line, was used. Results show that cholecalciferol, at physiological levels: (i) inhibits anchorage-dependent growth (ii) induces differentiation by increasing PSA expression and (iii) exerts its effects by up-regulating vitamin D receptor (VDR), retinoid-X receptors (RXRs), and androgen receptor (AR). Furthermore, we discovered that human prostate epithelial cells constitutively express appreciable levels of 25-hydroxylase CYP27A1 protein, the enzyme which catalyzes the conversion of cholecalciferol to 25(OH)D(3), and that CYP27A1 is up-regulated by cholecalciferol. Recent studies show that human mitochondrial CYP27A1 can also catalyze 1alpha-hydroxylation of 25(OH)D(3) to calcitriol. The presence of 25-hydroxylase in human prostate epithelial cells has not previously been shown. Since human prostate epithelial cells have the necessary enzymes and the rare ability to locally convert cholecalciferol to the active hormone calcitriol, we propose that they are a prime target for chemoprevention of prostate cancer with cholecalciferol whose safety is well established as a supplement in vitamins and fortified foods.

Detection and expression of human BK virus sequences in neoplastic prostate tissues

BK virus (BKV) is ubiquitous in the human population and establishes a lifelong, subclinical persistent infection in the urinary tract. When the immune system is compromised, it can cause severe disease in the kidney and bladder. Detection of BKV sequences in urinary tract neoplasms has led to the postulate that this virus may induce human oncogenesis through the function of its large tumor antigen (TAg). In this study, examination of prostate tumor tissue sections using in situ hybridization shows the presence of BKV sequences in atrophic epithelium. Solution polymerase chain reaction on DNA extracted from the tissues and sequence analysis of the products reveal the presence of BKV regulatory and early region sequences. In addition, immunohistochemical analysis using monoclonal antibodies specific to TAg or p53 shows the expression of TAg in some of the samples and p53 staining that can be correlated to TAg expression. Although the normal cellular localization of TAg and p53 is nuclear, double immunofluorescence labeling with anti-p53 and TAg antibodies indicates colocalization of p53 and TAg to the cytoplasm in the glandular epithelial cells of the sections. Although BKV DNA was found in benign and atrophic lesions, TAg and p53 coexpression was observed only in atrophic lesions.

Microvessel density as a molecular marker for identifying high-grade prostatic intraepithelial neoplasia precursors to prostate cancer

BACKGROUND

Existing clinical data have shown that high-grade prostatic intraepithelial neoplasia (HGPIN) is the most likely precursor to prostate cancer (CaP). Criteria to distinguish HGPIN that progress to CaP from those that do not remain poorly defined. Our objective was to evaluate microvessel density as a molecular marker for distinguishing HGPINs that have the potential of progressing to cancer.

MATERIALS AND METHODS

Human prostatic tissue samples were collected randomly from 50 prostatectomy and cystoprostatectomy patients. Formalin-fixed and paraffin-embedded sections were used for immunohistochemical localization of rabbit anti-human von Willebrand factor VIII (vWF) IgG, mouse anti-high molecular weight cytokeratin 34BE-12 in basal cells, and mouse anti-heparan sulphate proteoglycan (HSPG) IgGs in basement membranes associated with benign prostatic hyperplasia (BPH), PIN associated with some BPH (isolated PIN), and PIN associated with CaP.

RESULTS

Analysis of immunostaining data showed that PINs could be categorized according to their distributions within and outside 2 standard deviations (SD) of the mean for microvessel density. The average number of microvessels was significantly higher (P < 0.0001) in PINs associated with Gleason score 7 tumors than those associated with Gleason scores 4-6 (P < 0.1328) or 8 and 9 tumors (P < 0.1708). Morphologically, PINs within 2 SD were composed of low- and high-grade type, whereas those outside 2 SD of microvessel density were predominantly of high-grade type. Cytokeratin and HSPG localization patterns also showed differences in PINs found within and outside 2 SD of microvessel density. We found localization of cytokeratin 34BE-12 in basal cells of specimens with BPH alone, isolated PIN, and PIN associated with CaP within 2 SD, whereas many PINs outside 2 SD showed disruptions in cytokeratin localization. The basement membranes of PINs within 2 SD of microvessel density were relatively intact, whereas those outside 2 SD were fragmented.

CONCLUSIONS

Our immunostaining data indicates that once HGPIN is found in the initial prostatic biopsy, it should be evaluated for microvessel density by localization of vWF. Our data indicate that characteristics of HGPIN can be augmented by evaluations of cytokeratin and HSPG molecular markers to assess the potential of HGPIN progression to malignancy. When biopsy samples show HGPIN with increased microvessel density and disrupted cytokeratin and HSPG markers, the patient may be a candidate for repeat biopsy. Since our study is limited to 50 prostate tissue samples, we emphasize that our conclusion is tentative and ought to be confirmed in a study with a larger sample size. This is the first report to show that microvessel density may distinguish HGPIN that is a precursor to prostate cancer.

uPM3, a new molecular urine test for the detection of prostate cancer

OBJECTIVES

To evaluate, in a multicenter study, the diagnostic performance of a new molecular test uPM3 for detecting prostate cancer cells in urine because of the need for better methods to identify patients at risk of prostate cancer.

METHODS

The uPM3 test is a nucleic acid amplification assay detecting simultaneously in the urine the relative expression of prostate-specific antigen (PSA) mRNA as a marker of prostate cells and PCA3RNA, which is selectively expressed in most types of prostate cancer. The test is performed using the isothermic nucleic acid-based amplification method, and the two targets are simultaneously detected in real-time fluorescence using specific beacons as probes in a thermostated spectrofluorometer. The test was performed on the first voided urine obtained after careful digital rectal examination of the prostate in men undergoing transrectal ultrasound-guided prostate biopsy.

RESULTS

Of 517 patients undergoing biopsy at five centers, 443 (86%) had an assessable sample. Of those, 21%, 55%, and 24% had a total PSA level of less than 4 ng/mL, between 4 and 10 ng/mL, and greater than 10 ng/mL. The corresponding percentage of biopsies positive for cancer in these three groups was 20%, 35%, and 44%. The overall uPM3 sensitivity and specificity was 66% and 89%, respectively. In men with a PSA level less than 4 ng/mL, the sensitivity was 74% and specificity 91%. In those with a PSA level of 4 to 10 ng/mL, the sensitivity was 58% and specificity 91%. In those with a PSA level greater than 10 ng/mL, the sensitivity and specificity was 79% and 80%, respectively. The positive predictive value of uPM3 was 75% compared with 38% for total PSA, and the negative predictive value was 84% compared with 89% and 80% for a PSA cutoff of 2.5 and 4.0 ng/mL, respectively. The overall accuracy was 81% compared with 43% and 47% for total PSA at a cutoff of 2.5 and 4.0 ng/mL, respectively.

CONCLUSIONS

These results suggest that the uPM3 molecular urine test may be an important adjunct to current methods for the detection of early prostate cancer.

Prostatic Intraepithelial Neoplasia: An Update

High-grade prostatic intraepithelial neoplasia (HGPIN) is commonly encountered on prostate needle biopsies and, based on epidemiologic, molecular, and animal models, has proven to be the most significant risk factor for prostate cancer and likely represents the premalignant phase of prostatic adenocarcinoma. This lesion is characterized by cellular proliferations within pre-existing ducts and glands, with nuclear and nucleolar enlargement similar to prostate cancer. However, unlike cancer, HGPIN retains a basal cell layer identifiable by immunohistochemistry with the basal cell-specific antibody cytokeratin 34bE12. The incidence of HGPIN identified in needle biopsies is as high as 25%, increases with age, and coexists with prostate cancer in approximately 85% of cases. There appears to be no causal relationship between HGPIN and serum prostate-specific antigen (total, percent free, or density) or radiographic characteristics on transrectal ultrasound. In a large series, the identification of HGPIN on initial needle biopsy is associated with about a 35% risk of prostate cancer on subsequent biopsies. Thus, the finding of HGPIN on prostate needle biopsy necessitates a second biopsy in a patient eligible for curative treatment. As a precursor lesion, HGPIN is currently a target for chemopreventive strategies, including antiandrogens and nutritional supplementation.

Apoptosis incidence and protein expression of p53, TGF-beta receptor II, p27Kip1, and Smad4 in benign, premalignant, and malignant human prostate

Deregulation of apoptosis is involved in prostate cancer development and progression. This study involved an immunohistochemical "profiling" of prostate tissue specimens from patients who underwent prostatectomy for localized prostate cancer, to identify apoptosis-specific alterations associated with premalignant precursor lesions. Prostate tissue was pathologically evaluated, and areas of benign acini, high-grade prostate intraepithelial neoplasia (HGPIN), and prostate cancer were identified. Immunohistochemical analysis was performed to determine the expression of p27Kip1, a key cell cycle regulator, transforming growth factor (TGF)-beta receptor II (TbetaRII), a critical signaling effector of TGF-beta; Smad4, a downstream intracellular effector of TGF-beta signaling; p53, a key apoptosis regulator; and prostate-specific antigen (PSA), a clinical marker of prostate cancer. The apoptotic index of the same cell populations was determined using the transferase-mediated digoxigenin-tagged 16-desoxy-uridine-triphosphate nick end labeling assay. Our findings indicate a significant reduction in p27Kip1 immunoreactivity in HGPIN (P<0.0001) and prostate cancer (P<0.0001) compared with the benign tissue. A significant down-regulation was detected in TbetaRII expression in HGPIN and prostate cancer compared with benign prostatic hyperplasia (BPH)(P<0.001). A significant decrease was also observed in Smad4 levels in HGPIN and prostate cancer compared with BPH (P<0.001). Evaluation of the incidence of apoptosis revealed a significant decrease in the apoptotic index among the epithelial cell populations in HGPIN and a further decrease in prostate carcinoma (P<0.01). This reduced apoptotic index correlated with a significant increase in p53 immunoreactivity in the prostatic carcinoma foci. Prostate cancer cells exhibited strong nuclear staining for p53 compared with adjacent HGPIN (P<0.05) and the benign lesions of the same prostate specimens (P<0.05). A significant reduction in PSA immunostaining was detected in HGPIN and prostate carcinoma foci compared with the benign glandular epithelia (P<0.001). These results further define deregulation of TGF-beta signaling effectors as a molecular basis for loss of apoptotic control contributing to the development of prostate tumors. Identification of apoptotic regulators in precursor premalignant lesions may have prognostic significance in disease progression as well as therapeutic value for targeting prostate cancer.

Evaluation of genetic patterns in different tumor areas of intermediate-grade prostatic adenocarcinomas by high-resolution genomic array analysis

Prostate cancer is known for its highly heterogeneous histological appearance. Data concerning the cytogenetic content of areas with different histology are sparse. We have genetically evaluated 10 prostatic adenocarcinomas with intermediate histopathological grades (Gleason score 7) that showed two distinctive growth patterns with different pathologies, that is, Gleason grades 3 and 4 (G3 and G4). The G3 and G4 tumor specimens were taken from spatially separated regions within the cancer mass. Array-based comparative genomic hybridization (aCGH) was performed to obtain genotypes from the 10 pairs of G3 and G4 cancer areas. The cancer DNAs were retrieved from formalin-fixed and paraffin-embedded tissues allowing optimal recognition and selection of target cells. A genome-wide 2,400-element BAC array that provided high-resolution detection of both deletions and amplifications was used. In the 20 G3 and G4 areas, 252 genomic aberrations (88 gains, 164 deletions) were noted, of which 86 were concurrent in G3 and G4 areas (34% overlap). Ninety-five of the 252 alterations were defined by a single BAC clone (54 gains, 41 deletions). Overlapping changes were more frequent for deletions (46%) than for gains (13%). Frequent coinciding deletions (> or = 20% of tumors) were seen on 8p (60%), 6q (30%), 1p (20%), 2q (20%), proximal 8q (20%), 10q (20%), 13q (20%), 16q (20%), and 18q (20%). A frequent overlapping gain (> or = 20% of tumors) was detected on distal 13q (20%). The patterns of imbalance could be found to coincide in the G3 and G4 areas of the majority of cancers. Array-based CGH can be used as a tool for the evaluation of genetic patterns in prostate cancer.

Prostate Pathology of Genetically Engineered Mice: Definitions and Classification. The Consensus Report from the Bar Harbor Meeting of the Mouse Models of Human Cancer Consortium Prostate Pathology Committee

The Pathological Classification of Prostate Lesions in Genetically Engineered Mice (GEM) is the result of a directive from the National Cancer Institute Mouse Models of Human Cancer Consortium Prostate Steering Committee to provide a hierarchical taxonomy of disorders of the mouse prostate to facilitate classification of existing and newly created mouse models and the translation to human prostate pathology. The proposed Bar Harbor Classification system is the culmination of three meetings and workshops attended by various members of the Prostate Pathology Committee of the Mouse Models of Human Cancer Consortium. A 2-day Pathology Workshop was held at The Jackson Laboratory in Bar Harbor, Maine, in October 2001, in which study sets of 93 slides from 22 GEM models were provided to individual panel members. The comparison of mouse and human prostate anatomy and disease demonstrates significant differences and considerable similarities that bear on the interpretation of the origin and natural history of their diseases. The recommended classification of mouse prostate pathology is hierarchical, and includes developmental, inflammatory, benign proliferative, and neoplastic disorders. Among the neoplastic disorders, preinvasive, microinvasive, and poorly differentiated neoplasms received the most attention. Specific criteria were recommended and will be discussed. Transitions between neoplastic states were of particular concern. Preinvasive neoplasias of the mouse prostate were recognized as focal, atypical, and progressive lesions. These lesions were designated as mouse prostatic intraepithelial neoplasia (mPIN). Some atypical lesions were identified in mouse models without evidence of progression to malignancy. The panel recommended that mPIN lesions not be given histological grades, but that mPIN be further classified as to the absence or presence of documented associated progression to invasive carcinoma. Criteria for recognizing microinvasion, for classification of invasive gland-forming adenocarcinomas, and for characterizing poorly differentiated tumors, including neuroendocrine carcinomas, were developed and are discussed. The uniform application of defined terminology is essential for correlating results between different laboratories and models. It is recommended that investigators use the Bar Harbor Classification system when characterizing new GEM models or when conducting experimental interventions that may alter the phenotype or natural history of lesion progression in existing models.

Can the number of cores with high-grade prostate intraepithelial neoplasia predict cancer in men who undergo repeat biopsy?

OBJECTIVES

To evaluate whether the presence of, or the number of cores containing, high-grade prostatic intraepithelial neoplasia (PIN) found in men who underwent initial extended multisite biopsy could predict which men would have prostate cancer on subsequent repeat biopsies.

METHODS

Between June 1997 and January 2003, 1086 men underwent initial prostate biopsy for early detection of prostate cancer using an extended multisite biopsy scheme. Of these, 175 men without cancer underwent at least one repeat biopsy (range one to three; median interval between biopsies, 3 months). Among these 175 patients, 47 had high-grade PIN on initial biopsy.

RESULTS

The initial extended biopsy identified cancer in 33.8% (367 of 1086) and high-grade PIN in 20.8% (226 of 1086). The incidence of high-grade PIN only in patients found to have cancer on initial biopsy was 29.7% (109 of 367). The presence of high-grade PIN was associated with concurrent prostate cancer at the initial biopsy (P <0.0001). Overall, repeat biopsy identified cancer in 18.3% of the 175 men. Of the 47 men with high-grade PIN, 5 (10.6%) were found to have cancer on repeat biopsy. The number of biopsy specimens positive for high-grade PIN on initial biopsy was not associated with the likelihood of prostate cancer on repeat biopsy. Multivariate logistic regression analysis showed that neither the presence of high-grade PIN nor the number of cores containing high-grade PIN on initial biopsy were predictors for prostate cancer on repeat biopsy.

CONCLUSIONS

The number of cores positive for high-grade PIN was not predictive for cancer on repeat biopsy.

Use of interphase fluorescence in situ hybridization in prostate needle biopsy specimens with isolated high-grade prostatic intraepithelial neoplasia as a predictor of prostate adenocarcinoma on follow-up biopsy

Isolated high-grade prostatic intraepithelial neoplasia (HGPIN) on needle biopsy confers an increased risk of prostate carcinoma (CaP) on follow-up biopsy. The aim of this study is to determine whether paraffin-section fluorescence in situ hybridization (FISH) of specific chromosome/oncogene copy number abnormalities (CNAs) in biopsy specimens with isolated HGPIN increases the predictive value for CaP on repeat biopsy. Cases were divided into 3 groups: controls (n=8) and sextant biopsy specimens with isolated HGPIN without CaP (group A; n=11) and with CaP (group B; n=14) on follow-up biopsy. Dual-color FISH assessing c-myc, HER-2/neu, chromosome region 7q31 (D7S486), and corresponding chromosome centromeres was performed. An amplification ratio (AR) for each marker centromere was derived for each biopsy specimen, with AR ranges designated as no/low, low-intermediate, and high. Also calculated for each marker were the percentage of cells with marker amplification, hyperdiploidy, and monosomy. A composite score for each biopsy specimen was calculated based on these parameters, with a possible range of 0 to 15. The specific chromosomal oncogene CNAs were as follows: for chromosome 7/7q31, 2 of 11 (18%) in group A and 6 of 14 (43%) in group B; for chromosome 8/c-myc, 4 of 11 (36%) in group A and 9 of 13 (69%) in group B; and for chromosome 17/HER-2/neu, 10 of 10 (100%) in group A and 13 of 14 (93%) in group B. The mean composite score was 0 for controls, 2.5 for group A, and 4.7 for group B. Composite scores > or =4 for the 3 groups were 0 of 9 (0%) for controls, 1 of 11 (12%) for group A, and 8 of 14 (57%) for group B. These differences were statistically significant (P=0.015). One group A patient with a high composite score (6) had atypical small glands on follow-up biopsy at <1 year. Chromosome/oncogene CNAs are uncommon in control patients, occurring with increasing frequency and magnitude in patients with isolated HGPIN without and with follow-up CaP. Chromosome/oncogene CNAs in HGPIN are mostly of the low to intermediate level and display intercellular heterogeneity. HER-2/neu amplification is common in HGPIN with and without follow-up CaP. Chromosome 7 and 8 aneusomy and 7q31 and c-myc amplification are greater in HGPIN with follow-up CaP. Patients with isolated HGPIN and high composite score without follow-up CaP are uncommon; these patients may have a small, unsampled CaP. Although patients with HGPIN without CaP are more likely to have a low composite score, a subset of patients with follow-up CaP have low composite score, suggesting (1) mutational pathways independent of chromosomes 7, 8, and 17 and HER-2/neu, c-myc, and chromosome region 7q31 CNAs; (2) CaP derived from an independent, unsampled focus of HGPIN; or (3) CaP not derived from HGPIN.

In situ shortening of CAG repeat length within the androgen receptor gene in prostatic cancer and its possible precursors

BACKGROUND

The amino-terminal transcriptional activation domain of the androgen receptor (AR) gene contains two polymorphic trinucleotide repeat segments that encode polyglutamine (CAG)n and polyglycine (GGC)n tracts. Shorter CAG repeat lengths are associated with higher transcriptional activity. The previous studies using peripheral blood leukocytes showed the relationship between shorter CAG repeat length and risk for prostate cancer (PCA).

METHODS

Prostatic cancer (PCA), its possible precursors [high grade prostatic intraepithelial neoplasia (HGPIN) and postatrophic hyperplasia (PAH)], and non-neoplastic epithelium were microdissected from a whole-mount prostatectomy specimen from 34 cases with PCA. DNA extracted from each lesion was processed for PCR-based electrophoresis on 6% denaturing polyacrylamide gels, followed by direct sequencing. To examine whether the in situ shortening of CAG repeat was confined to the CAG repeat or was a part of phenomenon induced by microsatelite instability (MSI), BAT-25 and BAT-26, effective markers for detection of MSI, were also examined.

RESULTS

All non-neoplastic epithelial lesions had identical numbers of CAG repeat in the same prostate. CAG repeat lengths were identical in lesions in 25 cases. Two distinct products were found in 9 of 34 cases (26.5%); one product identical to that of non-neoplastic epithelium and another smaller one. In situ shortening of CAG repeat lengths in PCA, HGPIN, and PAH was found in 3 of 34 (8.8%), 6 of 34 (17.6%), and 3 of 10 (30%) cases, respectively. Frequency of CAG shortening was significantly higher in PAH than in PCA lesions (P < 0.05). The length of GGC repeats, BAT-25 and -26 was identical among all lesions in the same case. There was no significant correlation between shortening of CAG repeat length and the clinicopathologic parameters.

CONCLUSION

Shortening of CAG repeat length was found in in situ lesions of PCA and its possible precursors.

Pathologic characteristics of prostatic adenocarcinomas: a mapping analysis of Korean patients

Pathologic characteristics of the prostatic adenocarcinoma in Koreans are not clear. We studied 132 cases of prostatectomy specimens using mapping analysis to discover the pathologic characteristics of the Korean prostatic adenocarcinoma. Mean values were as follows: serum prostate-specific antigen level (sPSA), 16.4 ng/ml; tumor volume, 27.5%; size, 2.4 cm; Gleason score, 7.7; and p53 expression, 9.8%. Rates of multifocal tumors and high-grade prostatic intraepithelial neoplasm (HPIN) were 33.3 and 65.2%. The Gleason score, tumor volume%, tumor size and sPSA were correlated with each other. Korean prostatic adenocarcinomas showed higher Gleason scores, lower rates of HPIN and multifocality, and lower p53 expression in comparison to Western prostatic adenocarcinomas. These data may be a basis for pathologic characteristics of Korean prostatic adenocarcinoma that has now been increasing.

Apolipoprotein-D: a novel cellular marker for HGPIN and prostate cancer

BACKGROUND

High grade prostatic intraepithelial neoplasia (HGPIN) is a putative pre-malignant lesion of the prostate. While apolipoprotein-D (Apo-D), an androgen-regulated hydrophobic transporter protein, is expressed in prostate tumors, its expression in HGPIN is unknown.

METHODS

Immunoreactivity for Apo-D and another androgen-regulated protein, prostate specific antigen (PSA), was investigated in 64 radical prostatectomy tissues by video image analysis.

RESULTS

Eighty two percent of prostatectomy specimens demonstrated moderate to strong Apo-D immunoreactivity in areas of HGPIN. In comparison, weak Apo-D immunoreactivity was observed in non-malignant areas in only 24% of specimens. The median (range) percentage cellular area of HGPIN immunopositive for Apo-D (9.7%, 0-42.9), and the cellular concentration of Apo-D (MIOD 3.1, 0-13.3), were intermediate between that of normal (area 0%, 0-53.5%, MIOD 0, 0-12.6) and early stage prostate cancer tissues (area 29.2%, 0-90.8%, MIOD 6.7, 0-28.1). This increase in Apo-D expression from non-malignant, through HGPIN to prostate cancer was statistically significant (P < 0.001), and contrasted with the decrease observed in PSA staining between adjacent areas of normal glands, HGPIN, and cancer (P = 0.026).

CONCLUSIONS

The presence of high levels of immunoreactive Apo-D in HGPIN and prostate cancer, but not in non-malignant epithelial cells, is consistent with HGPIN being an intermediate lesion in the transition to prostate cancer, and suggests that cellular Apo-D expression is a marker of malignant transformation of the prostate.

Genetic mapping of allelic loss on chromosome 6q within heterogeneous prostate carcinoma

A number of genetic events have been reported in prostate carcinogenesis, including frequent loss of heterozygosity (LOH) on chromosomes 8q, 10q, 16q and 18q. In samples of heterogeneous, multifocal prostate carcinomas, we focused on chromosome 6q using PCR-based techniques with 15 microsatellite markers to identify the specific 6q deletion within tumors. LOH of one or more polymorphic markers was detected in 10 of 21 tumors (48%). Two of these 10 tumors demonstrated LOH in all cancerous foci at specific loci and 4 tumors showed deletion in one focus. Different deletion patterns were found in 3 tumors when different polymorphic markers were used. In 90% of tumors showing LOH in one or more foci, however, two common regions of LOH were identified; one at 1.81 cM on 6q15-16.3 between markers D6S1631 and D6S1056, and the other at 5.11 cM on 6q16-21 between markers D6S424 and D6S283. By RT-PCR analysis, the TAK1 gene located at these loci did not correlate with LOH status, indicating that TAK1 is not a target gene in prostate carcinoma. The 6q deletion occurs heterogeneously and LOH was more frequent in tumors of higher pathological stages, implying that this alteration is a late event in prostate carcinogenesis. Because prostate carcinomas are genetically multicentric and of multifocal origin, it remains unclear whether the foci containing 6q deletions specifically expand within tumors or to what extent they contribute to the histological heterogeneity characteristic of the disease.

Phase IIA Clinical Trial to Test the Efficacy and Safety of Toremifene in Men with High-Grade Prostatic Intraepithelial Neoplasia

Men with high-grade prostatic intraepithelial neoplasia (PIN) evident on prostate biopsy are at high risk for the eventual development of prostate cancer. The ability to reverse high-grade PIN may reduce the incidence or delay the development of prostate cancer. Toremifene (GTx-006, Acapodene trade mark ) is a selective estrogen receptor modulator that has been shown in the transgenic mouse model of prostate cancer to eliminate high-grade PIN and reduce the incidence of prostate cancer. This study was aimed at the evaluation of the safety and efficacy of toremifene in men diagnosed with high-grade PIN. This was an open-label, phase IIA clinical trial that enrolled 21 men (mean age, 64.7 years) with evidence of high-grade PIN on biopsy within 6 months of entry into the study. Eighteen of these men (86%) completed toremifene treatment (60 mg/day orally for 4 months) and then underwent follow-up prostate biopsy (8 cores) to determine high-grade PIN status. The effect of the drug on serum prostate-specific antigen (PSA), percentage of free PSA, testosterone, estradiol, and quality of life was also measured. After toremifene treatment, 72% of these 18 men (vs. 17.9% of historical controls) had no high-grade PIN on subsequent prostate biopsies. Mean PSA trended higher, and percentage of free PSA was increased. Quality of life was not significantly affected by treatment. There were 3 mild adverse events, and no serious adverse events. Toremifene appeared to reduce high-grade PIN in this small, exploratory trial. The drug was well tolerated. A double-blind, dose-finding, randomized, placebo-controlled phase IIB/III study is currently open to further study toremifene's activity against high-grade PIN and prostate cancer incidence.

High-grade prostatic intraepithelial neoplasia and prostate cancer risk reduction

High-grade prostatic intraepithelial neoplasia (PIN) is the earliest accepted stage in carcinogenesis, possessing most of the phenotypic and biochemical changes in cancer without invasion of the basal membrane of the acini. The support for high-grade PIN as the main premalignant lesion of prostate cancer is based on several lines of evidence derived from prostate cancer animal models, epidemiological, morphological, genetic, and molecular studies. The incidence of high-grade PIN averages 9% (range 4-16%) in prostate biopsies, representing 115,000 new cases of high-grade PIN diagnosed each year in the United States. Performing saturation prostate biopsies to rule out any coexistent prostate cancer followed by every 3-6 month serial repeated prostate biopsies is currently the only way in which to manage patients found to have high-grade PIN. Medical therapy for high-grade PIN may easily become the mainstay treatment for high-grade PIN. Treatment of high-grade PIN appears to be of clinical benefit notwithstanding the potential for prostate cancer risk reduction. These clinical benefits would reduce morbidity, enhance quality of life, delay surgery or radiation, and increase the interval for surveillance requiring invasive procedures.

Production of serum-free and total prostate-specific antigen due to prostatic intraepithelial neoplasia

OBJECTIVE

High serum total prostate-specific antigen (PSA) levels have proven to be predictive of concurrent cancer but the role of prostatic intraepithelial neoplasia (PIN) in the production of total (t) and free (f) PSA is still the subject of research. In this study we wanted to discover whether variations in serum fPSA and tPSA levels are caused by PIN.

MATERIAL AND METHODS

We reviewed the medical records of 87 patients: in 32 of them the diagnosis of isolated PIN was made from surgical samples (simple prostatectomy, n = 19; radical cystectomy, n = 13); in 30 patients a diagnosis of benign prostatic hyperplasia (BPH) without PIN or prostatic carcinoma was made after simple prostatectomy (n = 20) or radical cystectomy (n = 10); and in 25 patients a clinically significant prostatic cancer was diagnosed and these patients underwent radical prostatectomy. All patients underwent a standard preoperative evaluation, including serum fPSA and tPSA determinations and PSA density.

RESULTS

The frequency of isolated PIN in simple prostatectomy specimens was 6.3%. The mean f/t PSA ratios were 17.66% in the 32 patients with PIN, 19.2% in the 8 patients with low-grade PIN, 17.6% in the 24 patients with high-grade PIN, 24.2% in patients with BPH and 13% in patients who underwent radical prostatectomy.

CONCLUSIONS

We believe that to make a definitive diagnosis of isolated PIN without carcinoma, study of the whole prostate gland is necessary, in order to definitively exclude the presence of concurrent neoplastic foci. Our data show that PIN does not contribute to tPSA levels and density; however, it may be responsible for a slight reduction in the f/t PSA ratio, with a significant reduction in cases with high-grade PIN (17.6%) compared to those with BPH (24.2%).

Alpha-methylacyl-CoA racemase (P504S) expression in evolving carcinomas within benign prostatic hyperplasia and in cancers of the transition zone

Carcinomas of the transition zone (TZ) constitute approximately 20% of all prostate cancers. The TZ is the site of origin of grade 1 and grade 2 cancers, the most well-differentiated of the Gleason grade tumors, as well as for benign prostatic hyperplasia (BPH). In this regard, grade 1 carcinoma has architectural features that closely mimic gland-rich BPH nodules. Although a relationship between cancers arising in this zone and BPH has been suspected, such an association remains undefined. To gain insight into the origin, development, and progression of cancers arising in the TZ, we used a highly specific rabbit monoclonal antibody (P504S) directed against alpha-methylacyl-CoA racemase (AMACR) to study the expression of the enzyme in 25 cases of evolving and fully developed carcinomas of this zone. AMACR has been proposed as a new molecular marker for prostate cancer, because the enzyme is reportedly overexpressed in high-grade dysplasias, also termed prostatic intraepithelial neoplasia, a purported precursor of prostatic carcinoma, and in all grades of prostatic carcinoma of the peripheral zone. Using P504S, P63, or antikeratin 34beta E12 antibodies, we found it possible to define areas of transition from hyperplasia to carcinoma in 6 BPH nodules. In 3 other cancer-containing BPH nodules, staining for AMCAR was observed in benign hyperplastic glands that were juxtaposed to carcinoma. Enzyme expression was also evident in 5 additional cases in which BPH was found adjacent to cancer. In contrast; AMACR was not visualized in any other BPH nodules that we studied. Thus, using the enzyme as a marker, we document for the first time that some carcinomas of the TZ arise from an AMCAR-positive transition lesion within a subset of BPH nodules. Moreover, the finding of enhanced AMACR expression in benign glands within cancer-containing nodules as well as in BPH lesions adjacent to carcinoma suggests that in some cases, up-regulation of the enzyme may precede morphological evidence of neoplastic transformation. AMACR was lightly expressed in transition lesions and grade 1 carcinomas but more strongly expressed in higher-grade TZ cancers, suggesting that enzyme expression is enhanced with progression in this zone. Because AMACR is involved in the beta oxidation of branched fatty acids and their derivatives, enhanced expression of the enzyme in evolving carcinomas in BPH nodules, as well as its up-regulation in juxtaposed morphologically benign glands and grade 1 carcinomas, suggests that increased utilization of fatty acids may play an important role in carcinoma development and progression in the TZ.

Clinical management of prostatic intraepithelial neoplasia as diagnosed by extended needle biopsies

OBJECTIVE

To examine the results of the clinical management of patients with high-grade prostatic intraepithelial neoplasia (PIN), as diagnosed by extended needle biopsies.

PATIENTS AND METHODS

The clinical data were reviewed from a cohort of 387 men who underwent > or = 10 core prostate needle biopsies between 1 January 1996 and 31 December 1997 by one urologist (W.C.D.). Two study groups were identified; the first comprised 47 patients with only high-grade PIN and the second was a control group of 137 patients with only benign findings on their biopsies. Those patients with cancer, atypia or a prostatic biopsy with fewer than 10 cores were excluded. The clinical and histological data were evaluated. The criteria for re-biopsy were two successive increases in prostate specific antigen (PSA) level or any change in the findings on digital rectal examination (DRE). All patients were monitored at 6-12 month intervals.

RESULTS

Of the 387 patients, 46% had normal findings, 5.2% had atypia, 12.6% had PIN alone, 15 (3.9%) had PIN plus atypia, 6.7% had PIN plus cancer and 32.3% had cancer. There was no significant difference between the PIN and control groups in age, DRE, PSA level, prostate size (by ultrasonography), free testosterone level, number of the cores and time of follow-up (median 34.8 and 36.6 months for the PIN and control groups, respectively). Of the PIN and control groups, 21 (45%) and 43 (31%) respectively had at least one re-biopsy. Five patients (24%) in the PIN and one (2.3%) in the control group developed cancer (P = 0.0124). All these patients had organ-confined disease and were found to have either Gleason scores 3 + 3 or 3 + 4 on surgical specimens. There was no correlation between the original location of PIN and the location of subsequent malignancy.

CONCLUSIONS

Patients with one set of extended needle biopsies with high-grade PIN should be followed clinically every 6-12 months, and it may be safe to reserve repeat biopsy for those with changes in PSA level and/or in the DRE.

Distribution of inflammation, pre-malignant lesions, incidental carcinoma in histologically confirmed benign prostatic hyperplasia: a retrospective analysis

OBJECTIVES

We analyze our experience on BPH through 20 years of histopathological examinations performed by the same pathologist.

METHODS

We retrospectively reviewed all histopathological examinations performed from January 1979 to December 1998 in patients undergoing surgery in our urological clinic who were diagnosed with BPH. We limited our evaluation to the following variables in each BPH case analyzed: inflammatory aspects associated with BPH, presence of focal acinar atrophy, atypical adenomatous hyperplasia (AAH), prostatic intraepithelial neoplasia (PIN), incidental prostate carcinoma (IC). These histological variables were analyzed according to some clinical parameters such as age, prostate volume and serum PSA.

RESULTS

The study population was comprised of 3942 cases with histological diagnosis of BPH. The mean patient age was 68.85+/-7.67 years. In particular, inflammatory aspects were associated with BPH in a high percentage of cases (43.1% =1700 cases), predominantly as chronic inflammation. Observation of focal acinar atrophy significantly increased according to patient decade of age (p=0.027). There was a significant trend to increase with age decades (p=0.036) for high grade PIN. A significant difference was found in IC (T1a, T1b) distribution in the different decades of age and especially in regards to both T1a and T1b tumors, there was a trend to increase with patient age (p=0.020 and p=0.025, respectively). On the contrary, the distribution of inflammatory aspects (p<0.001) and AAH (p=0.003) significantly varied according to prostate volume, and particularly in regards to chronic inflammation, there was a trend to increase depending on the prostate volume (p=0.002). Only the presence of T1b tumor but not of the other histological parameters associated to BPH, was able to significantly influence serum PSA.

CONCLUSION

In our analysis different histological variables associated to BPH are differently influenced by the age of patients and prostate volume, and they differently influence serum PSA levels.

Canine prostate carcinoma: epidemiological evidence of an increased risk in castrated dogs

The present retrospective study investigated the frequency of prostate carcinoma (PCA) among prostate abnormalities in dogs and determined whether castration influences the incidence of PCA in dogs. During the years 1993-1998, 15,363 male dogs were admitted to the Utrecht University Clinic of Companion Animals, and of these dogs 225 were diagnosed with prostatic disease. In addition, another 206 male dogs were diagnosed as having prostatic disease based on cytologic examination of aspiration biopsies submitted by referring veterinarians. Benign prostatic hyperplasia was diagnosed in 246 dogs (57.1%), prostatitis in 83 dogs (19.3%), and PCA in 56 dogs (13%). Dogs with PCA were significantly older (mean age=9.9 years) than dogs with other prostatic diseases (mean age=8.4 years). The Bouvier des Flandres breed had an increased risk (odds ratio (OR)=8.44; 95% CI 4.38-16.1) of having PCA. Castration (26/56) increased the risk (OR=4.34; 95% CI 2.48-7.62) of PCA. The mean age at diagnosis of PCA in castrated dogs and in intact male dogs was not significantly different. The interval between castration and onset of prostatic problems was highly variable, suggesting that castration does not initiate the development of PCA in the dog, but it does favour tumor progression.

Postatrophic hyperplasia of the prostate in Japan: histologic and immunohistochemical features and p53 gene mutation analysis

BACKGROUND

Postatrophic hyperplasia (PAH) is one of the patterns of prostatic atrophy but has been regarded as a precursor of prostatic cancer (PCA) because of its possible increase in proliferative activity compared with simple atrophy and morphologic mimicry of PCA.

METHODS

Radical prostatectomy specimens obtained from 28 patients with PCA were analyzed by histologic and immunohistochemical methods by using 34 beta E12 and Ki-67 as primary antibodies. Tissue from PAH, PCA, high-grade prostatic intraepithelial neoplasia (HGPIN), a possible precursor of PCA, and benign hyperplasia were microdissected and p53 gene mutations were examined by the polymerase chain reaction-single strand conformation polymorphism method followed by direct sequencing.

RESULTS

Histologically, PAH consists of compactly arranged small acini with irregular atrophic-appearing contours, mimicking PCA. PAH lesions were detected in 7 (25%) of 28 cases with PCA: multifocal in 6 of 7 (85.7%) cases, maximum size of lesions ranged from 0.3 to 2.3 mm. Mild nuclear enlargement and small nucleoli were observed in all cases. Capsular or perineural invasion, crystalloids, and mitotic figures were not found in any case. Inflammatory changes and fibrosis near PAH were found in 100% and 71% of cases, respectively. PAH involved non-transition zone in all cases and occasionally involved transition zone. Forty-three percent of PAH lesions were in proximity (<2 mm) to PCA. None of the clinical and pathologic factors examined were correlated with the presence of PAH. Immunohistochemical analysis by using 34 beta E12 revealed intact basal cells. Proliferative activity defined by positive rate for labeling with MIB-1 antibody was intermediate between benign prostatic hyperplasia and HGPIN. The frequency of p53 mutations in PAH lesions was 5.3%, which was similar to that in HGPIN lesions (4.2%). Benign glands never showed mutations.

CONCLUSION

These findings suggested that PAH might be a precursor for PCA.

Prostatic stem cells

Multipotent cells within the epithelial compartment, together with phenotypically 'plastic' mesenchyma cells (stromal stem cells), provide a repository of protected genetic information from which the structure, stability and functionality of the prostate gland can be maintained. However, mere preservation of cells in a non-dividing state is insufficient to provide the necessary reservoir of information from which the structure and function of the prostate gland can be retained or recreated. Rather, there is a constant dynamic interaction, at the level of information exchange, between stem cells (whether epithelial or mesenchymal) and their surrounding environment (both humoral and physical). Thus, with respect to epithelial stem cells, these reside within environmental 'niches' which allow their controlled and limited proliferation while preserving genomic integrity. Similar 'mesenchymal niches' are also predicted to occur, although not yet identified, thus providing the multipotent source from which the full spectrum of stromal phenotypes might be regenerated. Recent data from studies of the haematopoietic and hepato-biliary systems indicate that the potential scope of stem cells far exceeds the immediate phenotypic complement of those tissues within which they originate, being dependent upon their precise environment as well as their genomic integrity.

Development of PIN and prostate adenocarcinoma cell lines: a model system for multistage tumor progression

Existing prostate cancer cell lines have been derived from late stages of human prostate cancer. In this paper, we present two cell lines generated from prostatic intraepithelial neoplasia (PIN), the precursor lesion for prostate adenocarcinoma. Pr-111 and Pr-117 were established from PIN lesions that developed in the C3(1)/Tag transgenic model of prostate cancer. Pr-111 and Pr-117 cells express simian virus 40 large T antigen (SV40 Tag) and are immortalized in culture, distinguishing them from normal prostate cells. The growth rates of these two cell lines are quite different; with Pr-111 cells growing much more slowly (doubling time approximately 40 hours) compared to Pr-117 cells (doubling time approximately 22 hours), and also show significantly different growth rates in different media. Both prostate cell lines express cytokeratin and androgen receptor (AR) with Pr-111 cells demonstrating androgen-dependent growth and Pr-117 cells exhibiting androgen-responsive growth characteristics. Athymic nude mice injected with Pr-111 cells either do not develop tumors or develop tumors after a long latency period of 14 weeks. Pr-117 cells, however, develop tumors by 3 to 6 weeks, suggesting that Pr-117 cells represent a later stage of tumor progression. These two novel cell lines will be useful for studying early stages of prostate tumor development and androgen responsiveness.

Molecular characterization of canine prostaglandin G/H synthase-2 and regulation in prostatic adenocarcinoma cells in vitro

Induction of PG G/H synthase-2 (PGHS-2), a key rate-limiting enzyme in the PG biosynthetic pathway, has been implicated in prostatic adenocarcinomas in humans and dogs in vivo, but the molecular control of PGHS-2 expression in prostate cancer remains poorly understood. Using the dog model, the specific objectives of this study were to clone and characterize canine PGHS-2, and to study the regulation of its transcript, protein, and activity in a canine prostatic adenocarcinoma (CPA) cell line in vitro. The canine PGHS-2 cDNA was cloned by a combination of cDNA library screening and 5'-rapid amplification of cDNA ends, and shown to contain a 5'-untranslated region of 28 bp, an open reading frame of 1815 bp, and a 3'-untranslated region of 1655 bp. The open reading frame encodes a 604-amino acid protein that is 89% identical to the human homolog. The regulation of PGHS-2 protein and PGE(2) synthesis was studied in CPA cells cultured in the absence or presence of graded doses of phorbol 12-myristate 13-acetate (PMA), TNFalpha, and lipopolysaccharides. Results from immunoblots, immunocytochemistry, and RIAs showed that PGHS-2 protein and PGE(2) were present at low levels in control cells and were significantly induced after agonist treatment (P < 0.05), with PMA being the strongest inducer. Northern blot analyses also revealed a significant increase of PGHS-2 mRNA by PMA, TNFalpha, and lipopolysaccharides treatment (P < 0.05). Agonist-dependent induction of PGHS-2 mRNA was not dependent on new protein synthesis (coincubation with cycloheximide; 10 microg/ml) but was blocked by transcription inhibitor actinomycin D (5 microg/ml), suggesting that PGHS-2 acts an immediate early-response gene in prostatic epithelial cells. Thus, this study characterizes for the first time the structure of canine PGHS-2 and provides an in vitro model to unravel the molecular basis of PGHS-2 expression in prostatic adenocarcinomas.

Racial differences in prostate carcinogenesis. Histologic and clinical observations

Racial differences in the prevalence of HGPIN and in the Gleason score of local stage cancers indicate that clinically observed racial differences in cancer incidence and stage at diagnosis reflect racial variability in prostate carcinogenesis. Exploration of genetic, hormonal, nutritional, and behavioral differences in black and white men may provide insight into the fundamental mechanisms of prostatic carcinogenesis and cancer progression.