Prostatic intraepithelial neoplasia

Precision therapy for cancer prevention by targeting carcinogenesis

Cancer represents a major global public health burden, with new cases estimated to increase from 14 million in 2012 to 24 million by 2035. Primary prevention is an effective strategy to reduce the costs associated with cancer burden. For example, measures to ban tobacco consumption have dramatically decreased lung cancer incidence and vaccination against human papillomavirus can prevent cervical cancer development. Unfortunately, the etiological factors of many cancer types are not completely clear or are difficult to actively control; therefore, the primary prevention of such cancers is not practical. In this review, we update the progress on precision therapy by targeting the whole carcinogenesis process, especially for three high-risk groups: (1) those with chronic inflammation, (2) those with inherited germline mutations, and (3) those with precancerous lesions like polyps, gastritis, actinic keratosis or dysplasia. We believe that attenuating chronic inflammation, treating precancerous lesions, and removing high-risk tissues harboring germline mutations are precision methods for cancer prevention.

Relevance of dog as an animal model for urologic diseases

We utilize animal models in urologic research to improve understanding of urinary physiology, determine the etiology of many urologic diseases, and discover and test novel therapeutic interventions. Dogs have a similar urinary tract anatomy and physiology to human and they develop many urologic diseases spontaneously. This chapter offers detailed comparisons of urinary tract anatomy, physiology, and the most common urologic diseases between humans and dogs. Dogs offer a unique opportunity for urologic research because they can be studied in research colonies and in client owned cohorts. Dogs also are among a limited number of non-human species that require continence and socially appropriate urinary behaviors (ex. going to the bathroom outside, training to not have submissive urination, etc.). These features make dogs unique in the animal kingdom and make them an ideal animal model for urologic research.

NKX3.1 Localization to Mitochondria Suppresses Prostate Cancer Initiation

Mitochondria provide the first line of defense against the tumor-promoting effects of oxidative stress. Here we show that the prostate-specific homeoprotein NKX3.1 suppresses prostate cancer initiation by protecting mitochondria from oxidative stress. Integrating analyses of genetically engineered mouse models, human prostate cancer cells, and human prostate cancer organotypic cultures, we find that, in response to oxidative stress, NKX3.1 is imported to mitochondria via the chaperone protein HSPA9, where it regulates transcription of mitochondrial-encoded electron transport chain (ETC) genes, thereby restoring oxidative phosphorylation and preventing cancer initiation. Germline polymorphisms of NKX3.1 associated with increased cancer risk fail to protect from oxidative stress or suppress tumorigenicity. Low expression levels of NKX3.1 combined with low expression of mitochondrial ETC genes are associated with adverse clinical outcome, whereas high levels of mitochondrial NKX3.1 protein are associated with favorable outcome. This work reveals an extranuclear role for NKX3.1 in suppression of prostate cancer by protecting mitochondrial function. SIGNIFICANCE: Our findings uncover a nonnuclear function for NKX3.1 that is a key mechanism for suppression of prostate cancer. Analyses of the expression levels and subcellular localization of NKX3.1 in patients at risk of cancer progression may improve risk assessment in a precision prevention paradigm, particularly for men undergoing active surveillance.See related commentary by Finch and Baena, p. 2132.This article is highlighted in the In This Issue feature, p. 2113.

The adaptive immune system promotes initiation of prostate carcinogenesis in a human c-Myc transgenic mouse model

Increasing evidence from epidemiological and pathological studies suggests a role of the immune system in the initiation and progression of multiple cancers, including prostate cancer. Reports on the contribution of the adaptive immune system are contradictive, since both suppression and acceleration of disease development have been reported. This study addresses the functional role of lymphocytes in prostate cancer development using a genetically engineered mouse model (GEMM) of human c-Myc driven prostate cancer (Hi-Myc mice) combined with B and T cell deficiency (RAG1^-/- mice). From a pre-cancerous stage on, Hi-Myc mice showed higher accumulation of immune cells in their prostates then wild-type mice, of which macrophages were the most abundant. The onset of invasive adenocarcinoma was delayed in Hi-MycRAG1^-/- compared to Hi-Myc mice and associated with decreased infiltration of leukocytes into the prostate. In addition, lower levels of the cytokines CXCL2, CCL5 and TGF-β1 were detected in Hi-MycRAG1^-/- compared to Hi-Myc mouse prostates. These results from a GEMM of prostate cancer provide new insights into the promoting role of the adaptive immune system in prostate cancer development. Our findings indicate that the endogenous adaptive immune system does not protect against de novo prostate carcinogenesis in Hi-Myc transgenic mice, but rather accelerates the formation of invasive adenocarcinomas. This may have implications for the development of novel treatment strategies.

A biospectroscopic analysis of human prostate tissue obtained from different time periods points to a trans-generational alteration in spectral phenotype

Prostate cancer is the most commonly-diagnosed malignancy in males worldwide; however, there is marked geographic variation in incidence that may be associated with a Westernised lifestyle. We set out to determine whether attenuated total reflection Fourier-transform infrared (ATR-FTIR) or Raman spectroscopy combined with principal component analysis-linear discriminant analysis or variable selection techniques employing genetic algorithm or successive projection algorithm could be utilised to explore differences between prostate tissues from differing years. In total, 156 prostate tissues from transurethral resection of the prostate procedures for benign prostatic hyperplasia from 1983 to 2013 were collected. These were distributed to form seven categories: 1983–1984 (n = 20), 1988–1989 (n = 25), 1993–1994 (n = 21), 1998–1999 (n = 21), 2003–2004 (n = 21), 2008–2009 (n = 20) and 2012–2013 (n = 21). Ten-μm-thick tissue sections were floated onto Low-E (IR-reflective) slides for ATR-FTIR or Raman spectroscopy. The prostate tissue spectral phenotype altered in a temporal fashion. Examination of the two categories that are at least one generation (30 years) apart indicated highly-significant segregation, especially in spectral regions containing DNA and RNA bands (≈1,000–1,490 cm⁻¹). This may point towards alterations that have occurred through genotoxicity or through epigenetic modifications. Immunohistochemical studies for global DNA methylation supported this. This study points to a trans-generational phenotypic change in human prostate.

Biopsy sampling and histopathological markers for diagnosis of prostate cancer

Prostate cancer is one of the most common malignant tumors and a leading cause of cancer-related morbidity and mortality. Irrespective of the method that allows for risk stratification of prostate cancer suspects, diagnosis relies on tissue sampling through prostate biopsy and subsequent histopathological evaluation. This provides critical information about disease aggressiveness, which is required for adequate patient management. Prostate biopsy methods have significantly evolved over the years, including the definition of indications, sampling schemes and use of imaging techniques (ultrasound and MRI) that allow for more accurate tissue sampling. In response to the challenges emerging from more precise collection of minute prostate tissue samples for analysis, histopathological assessment should include not only the observation of routinely stained sections, but also, and increasingly so, a series of ancillary techniques, especially immunohistochemistry, which increment the accuracy of prostate cancer diagnosis and may provide relevant information to guide patient management.

A new proposed rodent model of chemically induced prostate carcinogenesis: distinct time-course prostate cancer progression in the dorsolateral and ventral lobes

BACKGROUND

Characterization of novel rodent models for prostate cancer studies requires evaluation of either spontaneous and carcinogen-induced tumors as well as tumor incidence in different prostatic lobes. We propose a new short-term rodent model of chemically induced prostate carcinogenesis in which prostate cancer progression occurs differentially in the dorsolateral and ventral lobes.

METHODS

Adult gerbils were treated with MNU alone or associated with testosterone for 3 or 6 months of treatment. Tumor incidence, latency, localization, and immunohistochemistry (AR, PCNA, smooth muscle α-actin, p63, MGMT, and E-cadherin) were studied in both lobes.

RESULTS

Comparisons between both lobes revealed that lesions developed first in the DL while the VL presented longer tumor latency. However, after 6 months, there was a dramatic increase in tumor multiplicity in the VL, mainly in MNU-treated groups. Lesions clearly progressed from a premalignant to a malignant phenotype over time and tumor latency was decreased by MNU + testosterone administration. Three-dimensional reconstruction of the prostatic complex showed that the DL developed tumors exclusively in the periurethral area and showed intense AR, PCNA, and MGMT immunostaining. Moreover, VL lesions emerged throughout the entire lobe. MNU-induced lesions presented markers indicative of an aggressive phenotype: lack of basal cells, rupture of the smooth muscle cell layer, loss of E-cadherin, and high MGMT staining.

CONCLUSIONS

There are distinct pathways involved in tumor progression in gerbil prostate lobes. This animal provides a good model for prostate cancer since it allows the investigation of advanced steps of carcinogenesis with shorter latency periods in both lobes.

TMPRSS2- driven ERG expression in vivo increases self-renewal and maintains expression in a castration resistant subpopulation

Genomic rearrangements commonly occur in many types of cancers and often initiate or alter the progression of disease. Here we describe an in vivo mouse model that recapitulates the most frequent rearrangement in prostate cancer, the fusion of the promoter region of TMPRSS2 with the coding region of the transcription factor, ERG. A recombinant bacterial artificial chromosome including an extended TMPRSS2 promoter driving genomic ERG was constructed and used for transgenesis in mice. TMPRSS2-ERG expression was evaluated in tissue sections and FACS-fractionated prostate cell populations. In addition to the anticipated expression in luminal cells, TMPRSS2-ERG was similarly expressed in the Sca-1^hi/EpCAM⁺ basal/progenitor fraction, where expanded numbers of clonogenic self-renewing progenitors were found, as assayed by in vitro sphere formation. These clonogenic cells increased intrinsic self renewal in subsequent generations. In addition, ERG dependent self-renewal and invasion in vitro was demonstrated in prostate cell lines derived from the model. Clinical studies have suggested that the TMPRSS2-ERG translocation occurs early in prostate cancer development. In the model described here, the presence of the TMPRSS2-ERG fusion alone was not transforming but synergized with heterozygous Pten deletion to promote PIN. Taken together, these data suggest that one function of TMPRSS2-ERG is the expansion of self-renewing cells, which may serve as targets for subsequent mutations. Primary prostate epithelial cells demonstrated increased post transcriptional turnover of ERG compared to the TMPRSS2-ERG positive VCaP cell line, originally isolated from a prostate cancer metastasis. Finally, we determined that TMPRSS2-ERG expression occurred in both castration-sensitive and resistant prostate epithelial subpopulations, suggesting the existence of androgen-independent mechanisms of TMPRSS2 expression in prostate epithelium.

Precursor Lesions of Prostate Cancer

Several morphological lesions have been proposed that may act as potential precursor lesions of prostate cancer. These are the morphologically distinct entities of focal atrophy or post-atrophic hyperplasia (PAH), atypical adenomatous hyperplasia (AAH) or adenosis, and prostatic intraepithelial neoplasia (PIN). The diagnostic criteria of low-and high-grade PIN (LGPIN and HGPIN, respectively) and of lesions suspicious for cancer (LSC) have been established. In the present review, we present the current knowledge about the precursor lesions of prostate cancer. We focus on the epidemiology, pathogenesis, clinical markers, and differential diagnosis of PIN. The similarities between HGPIN and prostate cancer are also discussed. Furthermore, potential markers and management strategies (that is, repeat biopsy, chemoprevention, radical prostatectomy, radiotherapy) are outlined along with updated recommendations.

Application of a global proteomic approach to archival precursor lesions: deleted in malignant brain tumors 1 and tissue transglutaminase 2 are upregulated in pancreatic cancer precursors

BACKGROUND

Pancreatic cancer is an almost uniformly fatal disease, and early detection is a critical determinant of improved survival. A variety of noninvasive precursor lesions of pancreatic adenocarcinoma have been identified, which provide a unique opportunity for intervention prior to onset of invasive cancer. Biomarker discovery in precursor lesions has been hampered by the ready availability of fresh specimens, and limited yields of proteins suitable for large scale screening.

METHODS

We utilized Liquid Tissue, a novel technique for protein extraction from archival formalin-fixed material, and mass spectrometry to conduct a global proteomic analysis of an intraductal papillary mucinous neoplasm (IPMN). Tissue microarrays comprised of 38 IPMNs were used for validation of candidate proteins.

RESULTS

The proteomic analysis of the IPMN Liquid Tissue lysate resulted in identification of 1,534 peptides corresponding to 523 unique proteins. A subset of 25 proteins was identified that had previously been reported as upregulated in pancreatic cancer. Immunohistochemical analysis for two of these, deleted in malignant brain tumors 1 (DMBT1) and tissue transglutaminase 2 (TGM2), confirmed their overexpression in IPMNs.

CONCLUSION

Global proteomics analysis using the Liquid Tissue workflow is a feasible approach for unbiased biomarker discovery in limited archival material, particularly applicable to precursor lesions of cancer.

Prostate stem cell antigen (PSCA) mRNA expression in prostatic intraepithelial neoplasia: implications for the development of prostate cancer

BACKGROUND

Prior data clearly demonstrated the expression of prostate stem cell antigen (PSCA) mRNA in prostatic intraepithelial neoplasia (PIN) tissues. The purpose of the present investigation was to determine whether PSCA mRNA expression was associated with the presence of cancer in this disease.

METHODS

One hundred seventeen men were diagnosed with isolated PIN on initial prostate biopsy, 51 with low-grade form (LGPIN), and 66 with high-grade form (HGPIN). PSCA mRNA expression in initial PIN and subsequent cancer was examined by in situ hybridization (ISH). The differences of the PSCA mRNA expression level between the groups were analyzed by the Chi-square and Student's t-test. Univariate and multivariate logistic regression analyses were performed to evaluate the predictive performance of PSCA mRNA.

RESULTS

PSCA mRNA expression level in 34 subsequent cancers was statistically increased compared with their paired PIN (P < 0.001), with a Gleason's dependence. HGPIN showed statistically high PSCA mRNA expression compared with LGPIN (P < 0.01). PSCA mRNA expression levels were significantly stronger in the initial isolated LGPIN and isolated HGPIN with subsequent cancer than those without (P < 0.001 and P < 0.001, respectively). Multivariate logistic regression analysis demonstrated that only PSCA mRNA was predictive of the onset of subsequent cancer in patients with isolated LGPIN and in those with isolated HGPIN, respectively.

CONCLUSIONS

Our data identify PSCA mRNA in initial PIN as a significant predictor of subsequent cancer, suggesting that PSCA implies in prostatic tumorigenesis and may be used to identify the patients with isolated PIN who are at high risk for cancer onset in the disease process.

A proposal on the identification, histologic reporting, and implications of intraductal prostatic carcinoma

CONTEXT

Prostatic adenocarcinoma growing within acinar-ductal spaces (intraductal carcinoma) in contrast to high-grade prostatic intraepithelial neoplasia (HG-PIN) impacts negatively on patient outcome. There is currently no generally accepted definition of this lesion nor is it classified in the current prostate cancer grading system (Gleason).

OBJECTIVE

To define intraductal carcinoma of the prostate (IDC-P) with major and minor diagnostic criteria that clearly separate it from HG-PIN. The implications of such a lesion are discussed with proposals to incorporate this entity into the Gleason grading system.

DATA SOURCES

We reviewed all published data referring to intraductal spread of prostate carcinoma. Articles discussing endometrial, endometrioid, and ductal carcinoma are included.

CONCLUSIONS

Intraductal carcinoma of the prostate as defined by major criteria that include enlarged gland structures, neoplastic cells spanning the gland lumen, central comedonecrosis, and further supported by minor diagnostic criteria including molecular biological markers, separate this entity from HG-PIN. Despite its perimeter basal cells, IDC-P should be interpreted as biologically equivalent to Gleason pattern 4 or 5 adenocarcinoma. Several hypotheses are proposed as to the evolution of IDC-P, which is almost always a late event in prostate carcinoma progression. Diagnosis of IDC-P on needle biopsy should prompt therapeutic intervention rather than surveillance or repeat biopsy, as is the case for HG-PIN.

Methylseleninic acid enhances the effect of etoposide to inhibit prostate cancer growthin vivo

New therapeutic agents are needed for the treatment of androgen-independent prostate cancer (PrCa). We have investigated the effect of methylseleninic acid (MSA) on tumor stage-specific prostate cells derived from the C3 (1)/Tag model for PrCa: Pr111, a slow-growing and nontumorigenic cell line isolated from a prostate intraepithelial neoplasia lesion; Pr14, a tumorigenic line derived from a primary tumor; and Pr14C1, a sub-clone of Pr14 explanted from a lung metastasis. We demonstrate that MSA strongly inhibits cell growth and induces apoptosis in C3 (1)/Tag tumor cells, in a dose-dependent manner. A decrease in phosphorylated ERK1/2 and AKT was also found in tumor cells, but not in Pr111. Microarray analysis using affymetrix showed that the number of genes with an altered expression in tumor cells is significantly higher (p < 0.01) than in nontumoral cells. Pathways analyses revealed a decrease in the expression of genes involved in metabolism (Fabp5, Cyba), signal transduction (ERK, AKT), angiogenesis (neuropilin-1, Flt-4) and transcription (cAMP response element-binding protein) in tumor cells. The expression of neuropilin-1, a protein involved in VEGF signaling and tumor angiogenesis, was 97-fold repressed in Pr14 cells treated with MSA. Combination treatments using low doses of etoposide or taxotere (docetaxel), plus low doses of MSA revealed a strong enhancement of cell growth inhibition and apoptosis in tumor cells. Our in vivo studies using Pr14 cells xenografted into nude mice demonstrated that MSA significantly enhances the chemotherapeutical effect of etoposide, resulting in 78.3% tumor growth inhibition. These results suggest that MSA could be used against PrCa to enhance the effect of etoposide.

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.

Application of Genomic Technologies to Human Prostate Cancer

Prostate cancer is the most commonly diagnosed non-cutaneous malignancy in U.S. males and has a broad spectrum of clinical behavior ranging from indolent to lethal. Microarray technology has provided unprecedented opportunity to explore the genetic processes underlying prostate cancer by providing a comprehensive survey of a cell's transcriptional landscape. Prostate cancer, however, has posed significant challenges that have contributed to inconsistent results between studies and difficulty replicating findings. Despite these challenges, several important insights have been gained along with new clinical biomarkers of diagnosis and prognosis. Continued improvements in methods of tissue preparation, microarray technology and data analysis will overcome existing challenges and fuel future discoveries.

Bicalutamide 50 mg monotherapy in patients with isolated high-grade PIN: findings in repeat biopsies at 6 months

OBJECTIVES

To evaluate morphological findings in repeat biopsies in patients with isolated high-grade prostatic intraepithelial neoplasia (HGPIN) after a 6-month course of bicalutamide (Casodex) 50 mg/day.

METHODS

20 consecutive patients with isolated HGPIN in prostate biopsies were treated for 6 months with bicalutamide 50 mg/day. After treatment, the patients were resubmitted to prostate biopsy mapping. The control group included 22 untreated consecutive patients with isolated high-grade PIN with repeat biopsies taken 6 months after the initial biopsies.

RESULTS

In the initial biopsies of the treated group, HGPIN was monofocal in 12 patients and plurifocal in 8. In the repeat biopsies HGPIN was present in 2 patients, monofocal in both, whereas prostate adenocarcinoma (PCa) was discovered in one. In the control group, HGPIN was monofocal in 15 and plurifocal in 7. In the repeat biopsies HGPIN was present in six patients, being monofocal in three and plurifocal in the other three. PCa was present in one.

CONCLUSIONS

There was a lower incidence of HGPIN (treated group vs control: 10% vs 27.2%) after 6 months of bicalutamide. Reduction in its extent was also observed (treated group vs control: monofocal 100% vs 50%). Treatment did not affect the incidence of cancer (treated vs control: 5% vs 4.5%).

Current status of transrectal ultrasound-guided prostate biopsy in the diagnosis of prostate cancer

In contemporary practice, most prostate cancers are either invisible on ultrasound or indistinguishable from concurrent benign prostatic hyperplasia. Diagnosis therefore rests on prostate biopsy. Biopsies are not simply directed at ultrasonically visible lesions, as these would miss many cancers; rather the whole gland is sampled. The sampling itself is systematic, using patterns based on prostate zonal anatomy and the geographical distribution and frequency of cancer. This review explains the evolution of the prostate biopsy technique, from the classical sextant biopsy method to the more recent extended biopsy protocols (8, 10, 12, >12 and saturation biopsy protocols). Extended protocols are increasingly being used to improve diagnostic accuracy, especially in those patients who require repeat biopsy. This trend has been facilitated by the ongoing improvement in safety and acceptability of the procedure, particularly with the use of antibiotic prophylaxis and local anaesthesia. The technical details of these extended protocols are discussed, as are the current data regarding procedure-related morbidity and how this may be minimized.

Disruption of growth hormone signaling retards early stages of prostate carcinogenesis in the C3(1)/T antigen mouse

Recent epidemiological studies suggest that elevated serum titers of IGF-I, which are, to a large degree, regulated by GH, are associated with an increase in prostate cancer risk. The purpose of the current study was to develop the first animal models to directly test the hypothesis that a normal, functional GH/IGF-I axis is required for prostate cancer progression. The GH receptor (GHR) gene-disrupted mouse (Ghr(-/-)), which has less than 10% of the plasma IGF-I found in GHR wild-type mice, was crossed with the C3(1)/T antigen (Tag) mouse, which develops prostatic intraepithelial neoplasia driven by the large Tag that progress to invasive prostate carcinoma in a manner similar to the process observed in humans. Progeny of this cross were genotyped and Tag/Ghr(+/+) and Tag/Ghr(-/-) mice were killed at 9 months of age. Seven of eight Tag/Ghr(+/+) mice harbored prostatic intraepithelial neoplasia lesions of various grades. In contrast, only one of the eight Tag/Ghr(-/-) mice exhibited atypia (P < 0.01, Fischer's exact test). Disruption of the GHR gene altered neither prostate androgen receptor expression nor serum testosterone titers. Expression of the Tag oncogene was similar in the prostates of the two mouse strains. Immunohistochemistry revealed a significant decrease in prostate epithelial cell proliferation and an increase in basal apoptotic indices. These results indicate that disruption of GH signaling significantly inhibits prostate carcinogenesis.

Prostate cancer and the genomic revolution: Advances using microarray analyses

The emerging technology of microarray analysis allows the establishment of molecular portraits of prostate cancer and the discovery of novel genes involved in the carcinogenesis process. Many novel genes have already been identified using this technique, and functional analyses of these genes are currently being tested. The combination of microarray analysis with other recently developed high-throughput techniques, such as proteomics, tissue arrays, and gene promoter-methylation, especially using tissue microdissection methods, will provide us with more comprehensive insights into how prostate cancer develops and responds to gene-targeted therapies. Animal models of prostate cancer are being characterized by high throughput techniques to better define the similarities and differences between those models and the human disease, and to determine whether particular models may be useful for specific targeted therapies in pre-clinical studies. Although profiling of mRNA expression provides important information of gene expression, the development of proteomic technologies will allow for an even more precise global insight into cellular signaling and structural alterations during prostate carcinogenesis. Not only will the "omic" revolution change basic science, but it will lead to a new era of molecular medicine.

Incidentally detected prostate cancer in cystoprostatectomies: pathological and morphometric comparison with clinically detected cancer in totally embedded specimens

There are limited data regarding the pathological features of incidentally detected prostate cancer. Examination of cystoprostatectomy specimens obtained during bladder cancer treatment affords a unique opportunity to examine incidentally detected prostate cancer and determine its relationship with clinically detected prostate cancer obtained during radical prostatectomy. We compared the pathological findings of incidentally detected prostate cancer in 132 consecutive cystoprostatectomy specimens from patients treated for bladder cancer with a consecutive series of 228 radical prostatectomy specimens from patients treated for prostate cancer. All specimens were totally embedded and whole-mounted. Karyometry was evaluated in select subsets of patients from the study groups. Incidentally detected cancer was found in 42% of cystoprostatectomy specimens, and the cancers were of lower Gleason score and lower pathological stage with fewer positive surgical margins than in clinically detected cancers in age-matched radical prostatectomies. High-grade prostatic intraepithelial neoplasia (PIN) was present in 82% of radical prostatectomy specimens, in 70% of cystoprostatectomies with incidentally detected prostate cancer, and in 54% of cystoprostatectomies without prostate cancer. Mean nuclear and nucleolar area was lower in incidentally detected cancer and PIN when compared with clinically detected cancer and PIN, respectively, similar to the results with proliferative indices. We conclude that incidentally detected cancer is less aggressive than clinically detected cancer.

Review article Testosterone therapy in the ageing male: what about the prostate?

The concerns about testosterone therapy in ageing men with late-onset hypogonadism mainly address the risk of prostatic disease, i.e. either benign prostatic hyperplasia (BPH) or prostate cancer (PCa). Both conditions are highly dependent on androgen action and recent clinical data on the cancer-preventive effect of the 5alpha-reductase inhibitor finasteride have supported the possible role of androgens in PCa. However, the clinical data especially on the long-term effects of exogenous androgen substitution in regard to prostate safety are nonconclusive in many respects. As sufficient clinical studies on these risks will not be available in the near future, the approach of testosterone therapy towards prostate complications should be kept on a safe but practical basis. This review includes some recommendations in regard to testosterone therapy and prostate monitoring in patients with BPH and bladder outlet obstruction, with previous history of curative treatment for PCa or with prostatic intraepithelial neoplasia.

The role of the androgen receptor in the development of prostatic hyperplasia and prostate cancer

The androgen receptor (AR) is an androgen-inducible transcription factor characterized by a modular primary structure, with each module representing a distinct functional unit. After its interaction with androgens, the cytoplasmic AR is activated and translocated to the nucleus where it binds to target genes at the androgen responsive element(s) and recruits coregulators to form a multiprotein complex that interacts with transcriptional mediators and the basal transcription machinery to regulate gene transcription. Androgens play an essential role in the morphogenesis and physiology of the normal prostate. The etiology of benign prostatic hyperplasia (BPH) and prostatic neoplasia, which can progress to adenocarcinoma, is androgen-dependent, and reduction/obliteration of androgen action in the prostate has been the therapy of choice for BPH and prostate cancer. After androgen withdrawal and antiandrogen treatment, the androgen responsive prostate cancer cells cease to proliferate and undergo apoptosis, causing tumor regression. However, relapses are seen invariably, when tumors emerge as androgen-independent and apoptosis-resistant. Gene amplification and amino acid substitutions in the AR are detected at a high frequency in recurrent tumors. These changes confer growth advantage to the tumor cells due to either hypersensitivity of AR to low, castrate-level androgens or a realignment of the receptor conformation, leading to altered ligand specificity that enables antiandrogens, adrenal androgens and non-androgen steroids act agonistically to increase AR activity. Persistence of signaling by the wild-type AR in therapy-resistant tumors is due to the increased receptor activity caused by cross talk of AR with multiple intracellular signaling cascades, especially the growth factor activated MAP kinase/ERK and PI3 kinase/Akt pathways. Ablation of AR function using antisense oligodeoxynucleotides, ribozymes or small interference RNAs (RNAi) holds promise as future approaches to the successful treatment of hormone-refractory, apoptosis-resistant prostate tumors.

Predictors of prostate cancer on extended biopsy in patients with high-grade prostatic intraepithelial neoplasia: a multivariate analysis model

OBJECTIVE

To define the importance of extended biopsy in patients with high-grade prostatic intraepithelial neoplasia (HGPIN) and to define predictors of cancer in extended biopsy in patients with HGPIN, using multivariate analysis.

PATIENTS AND METHODS

In all, 83 patients with previous sextant biopsy of HGPIN had an extended 11-core biopsy taken. Patients with a negative biopsy for cancer were followed by serum prostate-specific antigen (PSA) and digital rectal examination (DRE) every 6 months. The extended biopsy was repeated in 21 patients. The criteria for second biopsy were an increase in PSA and/or abnormal changes on DRE. Overall, 49 patients had a transurethral resection of the prostate (TURP). The cancer-detection rate on extended biopsy was correlated with risk factors using the chi-square test and multivariate analysis.

RESULTS

Extended biopsy detected prostate cancer in 30 of the 83 men (36%), with positive cores in only 20 sextant biopsy sites (67%), in only seven in additional sites (23%), and both in three (10%). Of the 21 patients who had repeat extended biopsy, four (19%) had cancers. There were two carcinomas in the 49 TURP specimens (4%). The PSA level, DRE and transrectal ultrasonography findings were not predictive of cancer in extended biopsies (chi-square test). Patient age, PSA density and the number of cores with HGPIN (all P < 0.001) had a significant effect on the cancer-detection rate, and multivariate analysis showed that all three were independent predictors of cancer. A logistic regression model was designed to predict the probability of cancer in extended biopsy, with an overall accuracy of 78%.

CONCLUSION

Extended biopsy improved the cancer detection rate by 23% in patients with HGPIN. Patient age, PSA density and the number of cores with HGPIN were the only independent predictors of 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.

Human prostate cancer risk factors

Prostate cancer has the highest prevalence of any nonskin cancer in the human body, with similar likelihood of neoplastic foci found within the prostates of men around the world regardless of diet, occupation, lifestyle, or other factors. Essentially all men with circulating androgens will develop microscopic prostate cancer if they live long enough. This review is a contemporary and comprehensive, literature-based analysis of the putative risk factors for human prostate cancer, and the results were presented at a multidisciplinary consensus conference held in Crystal City, Virginia, in the fall of 2002. The objectives were to evaluate known environmental factors and mechanisms of prostatic carcinogenesis and to identify existing data gaps and future research needs. The review is divided into four sections, including 1) epidemiology (endogenous factors [family history, hormones, race, aging and oxidative stress] and exogenous factors [diet, environmental agents, occupation and other factors, including lifestyle factors]); 2) animal and cell culture models for prediction of human risk (rodent models, transgenic models, mouse reconstitution models, severe combined immunodeficiency syndrome mouse models, canine models, xenograft models, and cell culture models); 3) biomarkers in prostate cancer, most of which have been tested only as predictive factors for patient outcome after treatment rather than as risk factors; and 4) genotoxic and nongenotoxic mechanisms of carcinogenesis. The authors conclude that most of the data regarding risk relies, of necessity, on epidemiologic studies, but animal and cell culture models offer promise in confirming some important findings. The current understanding of biomarkers of disease and risk factors is limited. An understanding of the risk factors for prostate cancer has practical importance for public health research and policy, genetic and nutritional education and chemoprevention, and prevention strategies.

Prostate intraepithelial neoplasia induced by prostate restricted Akt activation: the MPAKT model

To determine whether Akt activation was sufficient for the transformation of normal prostate epithelial cells, murine prostate restricted Akt kinase activity was generated in transgenic mice (MPAKT mice). Akt expression led to p70S6K activation, prostatic intraepithelial neoplasia (PIN), and bladder obstruction. mRNA expression profiles from MPAKT ventral prostate revealed similarities to human cancer and an angiogenic signature that included three angiogenin family members, one of which was found elevated in the plasma of men with prostate cancer. Thus, the MPAKT model may be useful in studying the role of Akt in prostate epithelial cell transformation and in the discovery of molecular markers relevant to human 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.

Bronchiolar columnar cell dysplasia--genetic analysis of a novel preneoplastic lesion of peripheral lung

Atypical adenomatous hyperplasia is the only known precursor lesion of lung adenocarcinomas (ACs) so far. Here, we describe a new dysplastic lesion in the bronchioles of peripheral lung for which we propose the name bronchiolar columnar cell dysplasia (BCCD). Eight of fourteen BCCDs were successfully analyzed by means of comparative genomic hybridization (CGH). The average number of chromosomal aberrations was 2.6 in BCCD and 14.7 in concomitant AC. Among the aberrations were losses of 3p, 9, 13, 14 and gains of 1q, 17, 19q and 20q. Summarizing our data from morphological and genetic analysis, we conclude that BCCD is a preneoplasia of the bronchiolar epithelium and most probably represents an additional precursor lesion of lung adenocarcinomas.

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.

Contemporary pathology of prostate cancer

In less than 20 years since the introduction of serum PSA and the spring-loaded 18-gauge prostatic biopsy needle, pathologists have adjusted to the limited tissue requirements of narrow needle specimens to apply criteria for diagnosis and grading of prostate cancer, borrowing from lessons learned from radical prostatectomies. Substantial gains have been made during this period in the understanding of precancerous lesions, mimics of malignancy, the criteria for minimal cancer, variants of cancer, and treatment-induced changes. The light microscopic findings remain the criterion standard for diagnosis against which all new techniques should be measured. Numerous findings have proven to be of value, including simple quantitation of histopathologic features, cancer volume, perineural invasion, and others.

Prostate Cancer Prevention: What Do We Know Now, and When Will We Know More?

Prostate cancer prevention is now one of the most aggressively investigated areas of urologic oncology, with > 30,000 men currently participating in clinical trials in the United States alone. The Prostate Cancer Prevention Trial will complete end-of-study prostate biopsies in May 2004, and the Selenium and Vitamin E Cancer Prevention Trial is rapidly reaching its accrual goal 1-2 years ahead of schedule. These 2 studies will give definitive answers regarding 3 of the most important potential preventive interventions: finasteride, vitamin E, and selenium. Many phase II and biomarker-modulation studies are also ongoing, testing a host of other interventions. It is hoped that, within a short period of time, the clinician will be provided with strategies to reduce the risk of the disease.

High grade prostatic intraepithelial neoplasia is a disease

High grade prostatic intraepithelial neoplasia (PIN) is now widely accepted as the main premalignant lesion that has the potential to progress to prostate adenocarcinoma. High grade PIN is a standard diagnosis that must be included as part of the reported pathologic evaluation of prostate biopsies. Premalignant lesions that affect other organs have been identified and are treated when diagnosed such that the premalignant lesions itself are a disease (eg, carcinoma in situ of the bladder, colon polyps, and cervical dysplasia). Urologists should recognize that high grade PIN is a dangerous lesion and that it should be aggressively managed either by saturation biopsies of the prostate following the diagnosis of high grade PIN, or the more common recommendation--repeated prostate biopsies every 3 to 6 months for 2 years, then annually. Treatment of these precancerous lesions would appear to be of clinical benefit notwithstanding the potential for cancer prevention. These clinical benefits would reduce morbidity, enhance the quality of life, delay surgery or radiation, and increase the interval for surveillance requiring invasive procedures.