Search results

Bone-directed therapy in prostate cancer: Rationale and novel approaches

Fine-mapping of prostate cancer susceptibility loci in a large meta-analysis identifies candidate causal variants.

Prostate cancer is a polygenic disease with a large heritable component. A number of common, low-penetrance prostate cancer risk loci have been identified through GWAS. Here we apply the Bayesian multivariate variable selection algorithm JAM to fine-map 84 prostate cancer susceptibility loci, using summary data from a large European ancestry meta-analysis. We observe evidence for multiple independent signals at 12 regions and 99 risk signals overall. Only 15 original GWAS tag SNPs remain among the catalogue of candidate variants identified; the remainder are replaced by more likely candidates. Biological annotation of our credible set of variants indicates significant enrichment within promoter and enhancer elements, and transcription factor-binding sites, including AR, ERG and FOXA1. In 40 regions at least one variant is colocalised with an eQTL in prostate cancer tissue. The refined set of candidate variants substantially increase the proportion of familial relative risk explained by these known susceptibility regions, which highlights the importance of fine-mapping studies and has implications for clinical risk profiling.

BMP-regulated exosomes from Drosophila male reproductive glands reprogram female behavior.

Male reproductive glands secrete signals into seminal fluid to facilitate reproductive success. In Drosophila melanogaster, these signals are generated by a variety of seminal peptides, many produced by the accessory glands (AGs). One epithelial cell type in the adult male AGs, the secondary cell (SC), grows selectively in response to bone morphogenetic protein (BMP) signaling. This signaling is involved in blocking the rapid remating of mated females, which contributes to the reproductive advantage of the first male to mate. In this paper, we show that SCs secrete exosomes, membrane-bound vesicles generated inside late endosomal multivesicular bodies (MVBs). After mating, exosomes fuse with sperm (as also seen in vitro for human prostate-derived exosomes and sperm) and interact with female reproductive tract epithelia. Exosome release was required to inhibit female remating behavior, suggesting that exosomes are downstream effectors of BMP signaling. Indeed, when BMP signaling was reduced in SCs, vesicles were still formed in MVBs but not secreted as exosomes. These results demonstrate a new function for the MVB-exosome pathway in the reproductive tract that appears to be conserved across evolution.

Prostate Specific Antigen and Prostate Cancer in Chinese Men Undergoing Initial Prostate Biopsies Compared with Western Cohorts.

PURPOSE: We determined the characteristics of Chinese men undergoing initial prostate biopsy and evaluated the relationship between prostate specific antigen levels and prostate cancer/high grade prostate cancer detection in a large Chinese multicenter cohort. MATERIALS AND METHODS: This retrospective study included 13,904 urology outpatients who had undergone biopsy for the indications of prostate specific antigen greater than 4.0 ng/ml or prostate specific antigen less than 4.0 ng/ml but with abnormal digital rectal examination results. The prostate specific antigen measurements were performed in accordance with the standard procedures at the respective institutions. The type of assay used was documented and recalibrated to the WHO standard. RESULTS: The incidence of prostate cancer and high grade prostate cancer was lower in the Chinese cohort than the Western cohorts at any given prostate specific antigen level. Around 25% of patients with a prostate specific antigen of 4.0 to 10.0 ng/ml were found to have prostate cancer compared to approximately 40% in U.S. clinical practice. Moreover, the risk curves were generally flatter than those of the Western cohorts, that is risk did not increase as rapidly with higher prostate specific antigen. CONCLUSIONS: The relationship between prostate specific antigen and prostate cancer risk differs importantly between Chinese and Western populations, with an overall lower risk in the Chinese cohort. Further research should explore whether environmental or genetic differences explain these findings or whether they result from unmeasured differences in screening or benign prostate disease. Caution is required for the implementation of prostate cancer clinical decision rules or prediction models for men in China or other Asian countries with similar genetic and environmental backgrounds.

Achievements and perspectives in prostate cancer phase 3 trials from genitourinary research groups in Europe: Introducing the prostate cancer consortium in Europe

Context Phase 3 trials have made major contributions to advances in prostate cancer (PCa). However, funding limitations and excess bureaucracy are now making it difficult to conduct trials. Objective To describe the collaborative groups in Europe and their academic phase 3 PCa trials. Evidence acquisition Leaders of collaborative groups from Scandinavia, the European Organisation for Research and Treatment of Cancer (EORTC), France, Spain, the United Kingdom, Germany, Switzerland, The Netherlands, and Ireland were asked to provide information. Evidence synthesis Approximately 40 academic European phase 3 trials focussing on PCa have been completed, and about 10 are accruing patients. Cross-border trials have been successfully conducted led by EORTC (11), Scandinavian Prostate Cancer Group (9), European Association of Urology (1), Systemic Therapy in Advancing or Metastatic Prostate Cancer: Evaluation of Drug Efficiency (STAMPEDE) (1), and the French Genito-Urinary Tumor Group (1). Among these studies were practise-changing trials showing the superiority of prostatectomy over watchful waiting in patients <65 yr of age, the benefits of combining androgen-deprivation therapy (ADT) with radiation therapy (RXT) in high-risk localised disease, the superiority of long-term versus short-term ADT, the benefit of RXT in men treated with ADT, and the role of adjuvant RXT. To bridge the numbers gap for phase 3 studies, the Prostate Cancer Consortium in Europe (PEACE) is a recently established initiative that aims to favour cross-border networks of investigators. PEACE 1 is testing the addition of abiraterone and that of RXT directed at the primary cancer in patients with de novo metastatic PCa treated with ADT. PEACE 2 is testing the addition of cabazitaxel and that of pelvic irradiation in patients with at least two criteria for high-risk localised PCa. Conclusions European academic phase 3 trials have contributed to establishing the current standard treatment of PCa. The PEACE consortium was recently tasked with the goal of addressing unanswered questions and specific biology-related issues more efficiently. Patient summary The Prostate Cancer Consortium in Europe was established to conduct comparative trials aiming at assessing new treatments for prostate cancer patients.

Prostate cancer

INTRODUCTION Prostate cancer is the second leading cause of cancerspecific death in the USA and the UK.1 The increased awareness of this disease, in combination with serum testing for prostate-specific antigen (PSA), has led to an increase in the use of radical prostatectomy as a treatment for clinically organ-confined prostate cancer in the USA and elsewhere in the Western world.2 In England and Wales, the age-specific incidence peaked in 1994, with the subsequent rate decreasing towards the underlying trend in most age groups.3 Public awareness of the disease is clearly on the increase, partly because of media interest and growing general interest in men’s health issues.

Cross-sectional study evaluating data quality of the National Cancer Registration and Analysis Service (NCRAS) prostate cancer registry data using the Cluster randomised trial of PSA testing for Prostate cancer (CAP).

OBJECTIVES: To compare the completeness and agreement of prostate cancer data recorded by the National Cancer Registration and Analysis Service (NCRAS) with research-level data specifically abstracted from medical records from the Cluster randomised triAl of prostate specific antigen (PSA) testing for Prostate cancer (CAP) trial. DESIGN: Cross-sectional comparison study. PARTICIPANTS: We included 1356 men from the CAP trial cohort who were linked to the NCRAS registry. PRIMARY AND SECONDARY OUTCOME MEASURES: Completeness of prostate cancer data in NCRAS and CAP and agreement for tumour, node, metastases (TNM) stage (T1/T2; T3; T4/N1/M1) and Gleason grade (4-6; 7; 8-10), measured by differences in proportions and Cohen's kappa statistic. Data were also stratified by year and pre-2010 versus post-2010, when NCRAS reporting standards changed. RESULTS: Compared with CAP, completeness was lower in NCRAS for Gleason grade (41.2% vs 76.7%, difference 35.5, 95% CI 32.1 to 39.0) and TNM stage (29.9% vs 67.6%, difference 37.6, 95% CI 34.1 to 41.1). NCRAS completeness for Gleason grade (pre-2010 vs post-2010 31.69% vs 64%; difference 32.31, 95% CI 26.76 to 37.87) and TNM stage (19.31% vs 55.50%; difference 36.19, 95% CI 30.72 to 41.67) improved over time. Agreement for Gleason grade was high (Cohen's kappa, κ=0.90, 95% CI 0.88 to 0.93), but lower for TNM stage (κ=0.41, 95% CI 0.37 to 0.51) overall. There was a trend towards improved agreement on Gleason grade, but not TNM stage, when comparing pre-2010 and post-2010 data. CONCLUSION: NCRAS case identification was very high; however, data on prostate cancer grade was less complete than CAP, and agreement for TNM stage was modest. Although the completeness of NCRAS data has improved since 2010, the higher completeness rate in CAP demonstrates that gains could potentially be achieved in routine registry data. This study's findings highlight a need for improved recording of stage and grade data in the source medical records.

Expression of bone morphogenetic proteins in human prostatic adenocarcinoma and benign prostatic hyperplasia.

There are important interactions between prostatic tumours and bone. This study was designed to examine whether prostatic tissue can express bone inductive factors, in particular, the Bone Morphogenetic Proteins (BMPs). The polymerase chain reaction (PCR) has been used to screen for the expression of BMPs one to six in the prostatic tissue of patients with benign prostatic hyperplasia (BPH), non-metastatic prostatic adenocarcinoma and metastatic prostatic adenocarcinoma. BMPs were expressed in both benign and malignant prostate tissue and in the prostate tumour cell lines, PC3 and DU145. BMPs were also expressed in ocular melanoma tissue, a tissue which rarely metastasizes to bone. BMP-6 expression was detected in the prostate tissue of over 50% of patients with clinically defined metastatic prostate adenocarcinoma, but was not detected in non-metastatic or benign prostate samples or in ocular melanoma tissue. These findings suggest that the BMPs may play a role in the osteoinductive activity of prostate metastases and that the pattern of expression of BMPs may be important in the pathogenesis of osteoblastic metastases associated with prostate adenocarcinoma.

Flexible cystoscopy findings in patients investigated for profound lower urinary tract symptoms, recurrent urinary tract infection, and pain.

BACKGROUND AND PURPOSE: The National Institute of Clinical Excellence published guidelines in 2010 recommending the use of cystoscopy to investigate profound lower urinary tract symptoms (pLUTS), recurrent urinary tract infection (rUTI), and pain in men. Currently, there are no equivalent guidelines for women. We aimed to examine the diagnostic performance of flexible cystoscopy (FC) when it is used in this context in both men and women. PATIENTS AND METHODS: Results of all outpatient FCs undertaken in our department between April 2009 and March 2010 were examined retrospectively. Patients undergoing FC for the investigation of pLUTS, rUTI, or pain were included. Diagnostic performance was calculated, which was defined as the number of patients receiving a diagnosis of a clinically relevant abnormality at FC divided by the total number of patients undergoing FC for this indication. RESULTS: Of the 1809 patients who underwent FC during the study period, 113 underwent FC to investigate pLUTS, rUTI, or pain. Diagnostic performance was 11.5% (n=13), being 11.4%, 19.2%, and 0% in those with pLUTS, rUTI, and pain, respectively. Bladder cancer was diagnosed in one (0.9%) patient who underwent FC to investigate pLUTS but also had nonvisible hematuria. Urethral stricture was diagnosed in nine (8.0%) cases and intravesical calculi in four (3.5%) cases. CONCLUSION: Clinically relevant abnormalities were found in 11.5% of patients with pLUTS, rUTI, or pain, supporting recently published NICE guidelines recommending cystoscopy in patients with pLUTS or rUTI. Of the 17 patients who were investigated for pain, none was found to have clinically relevant abnormalities; further studies are needed to define the clinical utility of FC in these cases.

The polycomb group protein EZH2 is required for transcriptional repression of p21 and MMP7 in prostate cancer cells

Circulating microRNAs are associated with the development and progression of prostate cancer

Acupuncture in urological practice--a survey of urologists in England.

OBJECTIVE: To determine the feasibility of obtaining cooperation from urologists in carrying out large-scale studies on the efficacy of acupuncture for the treatment of urological conditions, based on urologists' general views and knowledge of acupuncture. METHODS: A questionnaire was distributed to 145 urologists within three training deaneries within England. RESULTS: A response rate of 70% (n=102) was achieved. The majority of urologists rated their knowledge of acupuncture as low (46%, n=46) and their general attitude towards acupuncture was neutral (54%, n=55). The majority of responding urologists (95%) thought that acupuncture may be of value in urological conditions, and acupuncture was suggested to patients by 30 urologists (29%). The urologists most likely to suggest acupuncture to their patients were typically over 40 years of age, more experienced, not in a training post, and since starting their urological career had changed their attitude towards acupuncture. In a multivariate analysis, a change of view regarding the efficacy of acupuncture was found to be the only variable significantly associated with a recommendation of acupuncture to patients. CONCLUSIONS: Although overall knowledge about acupuncture was poor, most responding urologists thought acupuncture may be useful for urological conditions. Those who had changed their views were most likely to suggest acupuncture to their patients. Acupuncture for urological conditions warrants further investigation and, as this study has shown high interest within the urological community large clinical trials involving multicentres may be feasible.

Screening for prostate cancer: an update.

OBJECTIVES: To review evidence regarding the potential introduction of prostate cancer screening programmes and highlight issues pertinent to the management of screen-detected prostate cancer. METHODS: Screening for prostate cancer is a controversial health care issue in general and urological practice. A PubMed database search was performed, followed by a systematic review of the literature, to examine the evidence base underlying prostate cancer screening. RESULTS: A prostate cancer screening programme should satisfy several key postulates prior to its introduction. To date, several of these postulates have not been satisfied, and the evidence available for prostate cancer screening is currently insufficient to warrant its introduction as a public health policy. The natural history of screen-detected prostate cancer remains poorly understood, and recent evidence suggests that a screening programme may detect a large number of men with indolent disease who may be subsequently overtreated. Several randomised clinical trials are currently in progress and it is hoped that they will provide robust evidence to inform future practice. CONCLUSIONS: National systematic prostate cancer screening programmes outside randomised clinical trial settings have not been implemented to date owing to lack of robust evidence that such programmes would improve survival and/or quality of life in men with screen-detected disease. Forthcoming results of clinical trials and the application of appropriate risk stratification to prevent overtreatment of indolent prostate cancer are likely to change practice in coming years.

The Polycomb Group protein EZH2 regulates actin polymerization in human prostate cancer cells.

BACKGROUND: The Polycomb Group protein EZH2 is implicated in prostate cancer progression. EZH2 promotes prostate cancer cell proliferation and invasiveness. We describe a link between EZH2 function and actin polymerization in prostate cancer cells. METHODS: Nuclear and cytoplasmic EZH2 expression in benign and malignant prostate tissue samples was assessed. An association between EZH2 function and actin polymerization in prostate cancer cells was investigated using siRNA-mediated knock-down of EZH2. Effects of EZH2 knock-down on actin polymerization dynamics were analyzed biochemically using immunoblot analysis of cell lysate fractions, and morphologically using immunocytochemistry. RESULTS: Cytoplasmic EZH2 is expressed at low levels in benign prostate epithelial cells and over-expressed in prostate cancer cells. Cytoplasmic EZH2 expression levels correlate with nuclear EZH2 expression in prostate cancer samples. Knock-down of EZH2 in PC3 prostate cancer cells increases the amount of F-actin polymerization, cell size, and formation of actin-rich filaments. CONCLUSIONS: Cytoplasmic EZH2 is over-expressed in prostate cancer cells. EZH2 function promotes a reduction in the pool of insoluble F-actin in invasive prostate cancer cells. EZH2 may regulate actin polymerization dynamics and thereby promote prostate cancer cell motility and invasiveness.

Changes in circulating microRNA levels associated with prostate cancer.

BACKGROUND: The aim of this study was to investigate the hypothesis that changes in circulating microRNAs (miRs) represent potentially useful biomarkers for the diagnosis, staging and prediction of outcome in prostate cancer. METHODS: Real-time polymerase chain reaction analysis of 742 miRs was performed using plasma-derived circulating microvesicles of 78 prostate cancer patients and 28 normal control individuals to identify differentially quantified miRs. RESULTS: A total of 12 miRs were differentially quantified in prostate cancer patients compared with controls, including 9 in patients without metastases. In all, 11 miRs were present in significantly greater amounts in prostate cancer patients with metastases compared with those without metastases. The association of miR-141 and miR-375 with metastatic prostate cancer was confirmed using serum-derived exosomes and microvesicles in a separate cohort of patients with recurrent or non-recurrent disease following radical prostatectomy. An analysis of five selected miRs in urine samples found that miR-107 and miR-574-3p were quantified at significantly higher concentrations in the urine of men with prostate cancer compared with controls. CONCLUSION: These observations suggest that changes in miR concentration in prostate cancer patients may be identified by analysing various body fluids. Moreover, circulating miRs may be used to diagnose and stage prostate cancer.

EZH2 promotes proliferation and invasiveness of prostate cancer cells.

BACKGROUND: The transcriptional repressor EZH2 is implicated in control of cell proliferation in embryonic, immortalized and transformed cells. EZH2 expression in prostate cancer correlates with progression to hormone-refractory and metastatic disease, but it is unknown whether EZH2 plays a specific role in the acquisition of an advanced prostate cancer phenotype. METHODS: Using siRNA knockdown, we investigated the role of EZH2 in maintenance of prostate cancer cell proliferation and invasiveness. Using LNCaP cells with inducible EZH2 overexpression, we investigated whether EZH2 upregulation promotes an aggressive phenotype. RESULTS: Knockdown of endogenous EZH2 reduced proliferation of androgen-responsive and androgen-independent prostate cancer cells. EZH2 knockdown also inhibited prostate cancer cell invasion. However, overexpression of EZH2 in androgen-responsive cancer cells did not appreciably affect either proliferation or invasiveness. CONCLUSIONS: EZH2 promotes proliferation and invasion of prostate cancer cells, which can account for the correlation between EZH2 expression levels and an adverse prostate cancer prognosis.

Innovations in serum and urine markers in prostate cancer: Current European research in the P-Mark project

An overview is given of serum and urine prostate cancer markers that are currently under investigation and subsequently the P-Mark project is introduced. There are many markers showing promise to overcome the limitations of prostate specific antigen (PSA). Eventually, these markers should be able to increase the specificity in diagnosis, differentiate between harmless and aggressive disease and identify progression towards androgen independence at an early stage. In the P-Mark project, several recently developed, promising markers will be evaluated using clinically well-defined biorepositories. Following successful evaluation, these markers will be validated on a sample set derived from two large, European, prostate cancer studies and used for the identification of special risk groups in the general population. In addition, novel markers will be identified in the same biorepositories by different mass spectrometry techniques. © 2005 Elsevier B.V. All rights reserved.

Innovations in serum and urine markers in prostate cancer current European research in the P-Mark project.

An overview is given of serum and urine prostate cancer markers that are currently under investigation and subsequently the P-Mark project is introduced. There are many markers showing promise to overcome the limitations of prostate specific antigen (PSA). Eventually, these markers should be able to increase the specificity in diagnosis, differentiate between harmless and aggressive disease and identify progression towards androgen independence at an early stage. In the P-Mark project, several recently developed, promising markers will be evaluated using clinically well-defined biorepositories. Following successful evaluation, these markers will be validated on a sample set derived from two large, European, prostate cancer studies and used for the identification of special risk groups in the general population. In addition, novel markers will be identified in the same biorepositories by different mass spectrometry techniques.

Prognostic value of serum markers for prostate cancer.

The incidence of prostate cancer has increased dramatically during the last 10-15 years and it is now the commonest cancer in males in developed countries. The increase is mainly caused by the increasing use of opportunistic screening or case-finding based on the use of prostate-specific antigen (PSA) testing in serum. With this approach, prostate cancer is detected 5-10 years before giving rise to symptoms and on average 17 years before causing the death of the patient. While this has led to detection of prostate cancer at a potentially curable stage, it has also led to substantial overdiagnosis, i.e. detection of cancers that would not surface clinically in the absence of screening. A major challenge is thus to identify the cases that need to be treated while avoiding diagnosing patients who will not benefit from being diagnosed and who will only suffer from the stigma of being a cancer patient. It would be useful to have prognostic markers that could predict which patients need to be diagnosed and which do not. Ideally, it should be possible to measure these markers using non-invasive techniques, i.e. by means of serum or urine tests. As it is very useful for both early diagnosis and monitoring of prostate cancer, PSA is considered the most valuable marker available for any tumor. Although the prognostic value of PSA is limited, measurement of the proportion of free PSA has improved the identification of patients with aggressive disease. Furthermore, the rate of increase in serum PSA reflects tumor growth rate and prognosis but, due to substantial physiological variation in serum PSA, reliable estimation of the rate of PSA increase requires follow-up for at least 2 years. Algorithms based on the combined use of free and total PSA and prostate volume in logistic regression and neural networks can improve the diagnostic accuracy for prostate cancer, and assays for minor subfractions of PSA and other new markers may provide additional prognostic information. Markers of neuroendocrine differentiation are useful for the monitoring of androgen-independent disease and various bone markers are useful in patients with metastatic disease.

Evaluating the PCPT risk calculator in ten international biopsy cohorts: results from the Prostate Biopsy Collaborative Group.

OBJECTIVES: To evaluate the discrimination, calibration, and net benefit performance of the Prostate Cancer Prevention Trial Risk Calculator (PCPTRC) across five European randomized study of screening for prostate cancer (ERSPC), 1 United Kingdom, 1 Austrian, and 3 US biopsy cohorts. METHODS: PCPTRC risks were calculated for 25,733 biopsies using prostate-specific antigen (PSA), digital rectal examination, family history, history of prior biopsy, and imputation for missing covariates. Predictions were evaluated using the areas underneath the receiver operating characteristic curves (AUC), discrimination slopes, chi-square tests of goodness of fit, and net benefit decision curves. RESULTS: AUCs of the PCPTRC ranged from a low of 56% in the ERSPC Goeteborg Rounds 2-6 cohort to a high of 72% in the ERSPC Goeteborg Round 1 cohort and were statistically significantly higher than that of PSA in 6 out of the 10 cohorts. The PCPTRC was well calibrated in the SABOR, Tyrol, and Durham cohorts. There was limited to no net benefit to using the PCPTRC for biopsy referral compared to biopsying all or no men in all five ERSPC cohorts and benefit within a limited range of risk thresholds in all other cohorts. CONCLUSIONS: External validation of the PCPTRC across ten cohorts revealed varying degree of success highly dependent on the cohort, most likely due to different criteria for and work-up before biopsy. Future validation studies of new calculators for prostate cancer should acknowledge the potential impact of the specific cohort studied when reporting successful versus failed validation.