Risk factors for prostate cancer

The anticancer potential of metformin on prostate cancer

BACKGROUND

Prostate cancer (PCa) is characterized as the most frequent type of cancer in males. Recent research has suggested patients who have diabetes mellitus taking metformin (MF) have a lower risk of PCa. MF has antineoplastic effects such as adenosine monophosphate-activated protein kinase (AMPK)-dependent and independent mechanisms, suppression of androgen signaling pathway, and alterations of insulin-like growth factor-1 (IGF-1) signaling pathways that cause the growth and proliferation of PCa. Based on epidemiological factors, patients with diabetes mellitus may have a protective effect on PCa.

METHODS

A literature search on MEDLINE® was conducted using a combined query of "prostate cancer" and "metformin" to yield publications unveiling the mechanisms of action, biological effects, epidemiological evidence, and research advances of MF with respect to PCa.

RESULTS

Evidence has shown that MF has multiple antineoplastic effects through AMPK-dependent and independent mechanisms, the alteration of IGF-1 signaling pathways, suppression of the androgen receptor pathway, inhibition of the mTOR pathway, and lipogenesis. Conduction of meta-analysis suggests mortality benefit to patients who exhibit PCa when taking MF. Clinical trials have shown evidence, demonstrating MF to improving significantly.

CONCLUSIONS

Herewith we review the literature regarding the numerous mechanisms of action of MF on PCa in order to decrease or repress the growth, proliferation, and differentiation of PCa cells. We analyze the molecular impacts of MF as well as adjunct therapies such as androgen deprivation therapy, aspirin, statin, or chemotherapy, proposing that MF may have a future role in the treatment protocol of PCa whether as a monotherapy or in combination with other drugs.

Prostate Cancer Gene Regulatory Network Inferred from RNA-Seq Data

BACKGROUND

Cancer is a complex disease with a lucid etiology and in understanding the causation, we need to appreciate this complexity.

OBJECTIVE

Here we are aiming to gain insights into the genetic associations of prostate cancer through a network-based systems approach using the BC3Net algorithm.

METHODS

Specifically, we infer a prostate cancer Gene Regulatory Network (GRN) from a large-scale gene expression data set of 333 patient RNA-seq profiles obtained from The Cancer Genome Atlas (TCGA) database.

RESULTS

We analyze the functional components of the inferred network by extracting subnetworks based on biological process information and interpret the role of known cancer genes within each process. Fur-thermore, we investigate the local landscape of prostate cancer genes and discuss pathological associa-tions that may be relevant in the development of new targeted cancer therapies.

CONCLUSION

Our network-based analysis provides a practical systems biology approach to reveal the collective gene-interactions of prostate cancer. This allows a close interpretation of biological activity in terms of the hallmarks of cancer.

Intake of Non-steroidal Anti-inflammatory Drugs and the Risk of Prostate Cancer: A Meta-Analysis

Background: Epidemiological evidences regarding the association between the use of non-steroidal anti-inflammatory drugs (NSAIDs) and the risk of prostate cancer (PC) is still controversial. Therefore, we conducted a meta-analysis to explore the controversy that exists.

Methods: Electronic databases including Medline, EMBASE, Web of Science, Cochrane Library, BIOSIS, Scopus, CBM, CNKI, WANFANG, and CQVIP were used to search for and identify eligible studies published until December 31, 2017. Pooled effect estimates for the relative risk (RR) were computed through fixed-effects or random-effects models as appropriate. Publication bias was evaluated by Egger's and Begg's tests and potential sources of heterogeneity were investigated in subgroup analyses.

Results: A total of 43 observational studies were eligible for this meta-analysis. A protective effect was identified for the intake of any NSAIDs on the risk of PC (pooled RR = 0.89, 95% CI = 0.81–0.98). Moreover, the long-term intake of NSAIDs (≥5 years rather than ≥4 years) was associated with reduced PC incidence (pooled RR = 0.882, 95% CI = 0.785–0.991). Aspirin intake was also associated with a 7.0% risk reduction of PC (pooled RR = 0.93, 95% CI = 0.89–0.96). The inverse association became stronger for advanced PC and PC with a Gleason score ≥7 compared to the association with total PC. Interestingly, it was the daily dose (≥1 pill/day) rather than, long-term aspirin intake (≥4 or ≥5 years) that was associated with reduced PC incidence (pooled RR = 0.875, 95% CI = 0.792–0.967). The pooled effects for non-aspirin NSAIDs demonstrated no significantly adverse or beneficial effects on total PC, advanced PC, or PC with Gleason score ≥7, though all pooled RRs were >1.

Conclusions: Our findings suggested a protective effect of the intake of any NSAIDs on the risk of PC, especially in those who took the NSAIDs for a long period. Moreover, aspirin intake was also associated with a decreased risk of PC, and there was a dose related association between aspirin intake and the risk of PC, while no significant effects of long-term aspirin intake were found on the PC incidence.

Adherence to Mediterranean diet and prostate cancer risk in Sicily: population-based case-control study

Prostate cancer (PCa) is the second most frequently diagnosed cancer and the sixth leading cause of death from cancer worldwide. Countries following a Mediterranean-type dietary pattern, has been reported to have lower PCa incidence and mortality compared with other European regions. A population-based case-control study has been conducted from January 2015 to December 2016 in a single institution of the municipality of Catania, southern Italy. A total of 118 PCa and 238 population-based controls were collected. Controls had significantly higher adherence to the Mediterranean diet, which was evident for several subgroups (including age groups, overweight and obese men, current smokers, alcohol intake, low and medium physical activity levels). PCa cases were found to consume lower amount of vegetables (223 g/d vs. 261 g/d; p = 0.001), legumes (34.26 g/d vs. 53.55 g/d; p = 0.003), and fish (47.75 g/d vs. 58.3 g/d) than controls; other differences emerged were related to alcohol intake (12.37 g/d vs 5.07 g/d; p < 0.01), cereals (254.06 g/d vs.235.94 g/d; p < 0.001), dairy (196 g/d vs. 166 g/d; p < 0.001), and meat consumption (98.09 g/d vs. 70.15 g/d; p < 0.001). However, no statistically significant differences between cases and controls were found regarding fruit, legumes, and olive oil consumption. The Mediterranean diet score was inversely associated with lower likelihood of having PCa in a linear manner (odds ratio [OR]: 0.86 [95% CI 0.77-0.96]). Specifically, individuals in the highest group of adherence had 78% less likelihood of have PCa and 14% less likelihood for each point increase of the score. The model adjusted for total polyphenol intake showed still a significant inverse association between adherence to the Mediterranean diet and PCa, but the relation was no more linear and not significant for one-point increase of the score (OR: 0.88 [95% CI 0.77-1.01]). In our cohorts of Italian men, we observed that high adherence to the Mediterranean diet was inversely associated with likelihood of having PCa cancer.

Narrative medicine in metastatic prostate cancer reveals ways to improve patient awareness & quality of care

AIM

To describe the journey of patients with metastatic castration-resistant prostate cancer (mCRPC) in treatment with radium-223.

METHODS

A multiperspective analysis was performed using narrative medicine in four Italian centers.

RESULTS

The substantial impact of mCRPC on quality of life through all phases of the disease was described. After an initial lack of awareness of the disease or denial of its effects, symptoms of pain, fatigue and side effects often led to sadness, fear and loneliness. The majority underwent radium-223 therapy positively, restoring their quality of life and routine activities.

CONCLUSION

Using narrative medicine, the importance of a patient-centered approach in the pathway of care for patients with mCRPC through all the stages of the disease was highlighted.

Influence of HOTAIR rs920778 and rs12826786 genetic variants on prostate cancer risk and progression-free survival

Aim: Evaluate the impact of the single nucleotide polymorphisms rs920778 and rs12826786 in the long noncoding RNA HOTAIR in the susceptibility and prognosis of prostate cancer (PCa) patients. Patients & methods: HOTAIR single nucleotide polymorphisms were genotyped by restriction fragment length polymorphism in 151 PCa cases and 180 cancer-free controls. Odds ratio, 95% CIs and prognostic significance were calculated. Results: Our data showed no statistically significant associations between HOTAIR polymorphic variants in rs920778 and rs12826786 and PCa susceptibility. However, the CC genotype in rs12826786 was significantly associated with shorter biochemical recurrence-free survival in pT3-stage PCa patients. Conclusion: Our results indicate that HOTAIR rs12826786 CC genotype may be an independent prognostic biomarker in a particular subset of PCa tumors.

Epidemiology of prostate and kidney cancer in the Aboriginal population of Canada: A systematic review

INTRODUCTION

Prostate and kidney cancer rates in the Aboriginal population of Canada is a growing issue.

METHODS

A systematic review of prostate and kidney cancer epidemiology in the Aboriginal population of Canada was performed with international comparison and evaluation of present epidemiological disparities. PubMed, Medline, and Embase (from January 1946 to June 2016), relevant government-published reports, and the websites of organizations contributing to prostate or kidney cancer guidelines were searched. We included studies that informed any of the three epidemiological questions this review is focused on answering.

RESULTS

Two systematic reviews, two meta-analyses, five literature reviews, and 21 single-study papers were included. The incidence and mortality rates of kidney cancer were elevated among Canadian Aboriginals when compared to the provincial or national population and to several international regions. No studies reported data on survival. Prostate cancer incidence, mortality, and survival rates were lower in Aboriginals provincially, nationally, and internationally, with incidence and survival reaching statistical significance. Elevated rate of risk factors for kidney cancer was a significant finding among Canadian Aboriginals. Aboriginals were screened for prostate cancer less than the general Canadian population, a trend also observed in the U.S.

CONCLUSIONS

The elevated incidence and mortality of kidney cancer among Canadian Aboriginals is most likely attributable to the rise in lifestyle-based risk factors. Two correlations concerning prostate cancer are made. However, due to temporal and regional disparities in data, further investigation is required to elucidate these observations.

Chrysin induces death of prostate cancer cells by inducing ROS and ER stress

Chrysin is a natural flavone found in numerous plant extracts, honey, and propolis that has multiple biological activities including anti-cancer effects. Understanding of biological mechanisms mediated in response to chrysin in cancerous cells may provide novel insight into chemotherapeutic approaches with reduced side effects in cancers. In the present study, we investigated functional roles of chrysin in progression of prostate cancer cells using DU145 and PC-3 cell lines. The results showed that chrysin induced apoptosis of cells evidenced by DNA fragmentation and increasing the population of both DU145 and PC-3 cells in the sub-G₁ phase of the cell cycle. In addition, chrysin reduced expression of proliferating cell nuclear antigen in the prostate cancer cell lines compared to untreated prostate cancer cells. Moreover, chrysin induced loss of mitochondria membrane potential (MMP), while increasing production of reactive oxygen species (ROS) and lipid peroxidation in a dose-dependent manner. Also, it induced endoplasmic reticulum (ER) stress through activation of unfolded protein response (UPR) proteins including PRKR-like ER kinase (PERK), eukaryotic translation initiation factor 2α (eIF2α), and 78 kDa glucose-regulated protein (GRP78) in DU145 and PC-3 cells. The chrysin-mediated intracellular signaling pathways suppressed phosphoinositide 3-kinase (PI3K) and the abundance of AKT, P70S6K, S6, and P90RSK proteins, but stimulated mitogen-activated protein kinases (MAPK) and activation of ERK1/2 and P38 proteins in the prostate cancer cells. Collectively, these results indicate that chrysin initiates cell death through induction of mitochondrial-mediated apoptosis and ER stress, and regulation of signaling pathways responsible for proliferation of prostate cancer cells.

Erectile dysfunction and the risk of prostate cancer

Background

Prostate cancer (PCa) is the most commonly diagnosed malignancy and the third leading cause of cancer death among men in developed countries. Because some risk factors are common between erectile dysfunction (ED) and PCa, we investigated the association between ED and subsequent PCa.

Methods

This nationwide population-based cohort study used data from the Taiwan National Health Insurance Research Database for the period 2000–2010. We identified patients newly diagnosed with ED by using codes from the International Classification of Diseases, Ninth Revision, Clinical Modification.

Results

In total, 5858 and 23432 patients were enrolled in the ED and non-ED cohorts, respectively. After adjustment for age, sex, and comorbidities, the overall incidence densities of PCa were significantly higher in the ED cohort than in the non-ED cohort, with an adjusted hazard ratio (aHR) of 1.19. The age-specific relative risk of PCa was significantly higher for all age groups in the ED cohort than in the non-ED cohort. Compared with patients without ED, those with organic ED had a 1.27-fold higher risk of PCa.

Conclusion

ED is a harbinger of PCa in some men. Physicians should consider the possibility of occult PCa in patients with ED regardless of age and comorbidities.

DNA Methylation-Mediated Downregulation of DEFB1 in Prostate Cancer Cells

Epigenetic aberrations play crucial roles in prostate cancer (PCa) development and progression. The DEFB1 gene, which encodes human ß-defensin-1 (HBD-1), contributes to innate immune responses and functions as a potential tumor suppressor in urological cancers. We investigated whether differential DNA methylation at the low CpG-content promoter (LCP) of DEFB1 was associated with transcriptional regulation of DEFB1 in PCa cells. To identify distinct CpG loci within the DEFB1 LCP related to the epigenetic regulation of DEFB1, we performed an in vitro methylated reporter assay followed by bisulfite sequencing of the DEFB1 promoter fragment. The methylation status of two adjacent CpG loci in the DEFB1 LCP was found to be important for DEFB1 expression in PCa cells. Paired epithelial specimens of PCa patients (n = 60), which were distinguished as non-tumor and tumor tissues by microdissection, were analyzed by bisulfite pyrosequencing of site-specific CpG dinucleotide units in the DEFB1 LCP. CpG methylation frequencies in the DEFB1 LCP were significantly higher in malignant tissues than in adjacent benign tissues across almost all PCa patients. These results suggested that methylation status of each CpG site in the DEFB1 promoter could mediate downregulation of DEFB1 in PCa cells.

Adult body size, sexual history and adolescent sexual development, may predict risk of developing prostate cancer: Results from the New South Wales Lifestyle and Evaluation of Risk Study (CLEAR)

Prostate cancer (PC) is the most common non-cutaneous cancer in men worldwide. The relationships between PC and possible risk factors for PC cases (n = 1,181) and male controls (n = 875) from the New South Wales (NSW) Cancer, Lifestyle and Evaluation of Risk Study (CLEAR) were examined in this study. The associations between PC risk and paternal history of PC, body mass index (BMI), medical conditions, sexual behaviour, balding pattern and puberty, after adjusting for age, income, region of birth, place of residence, and PSA testing, were examined. Adjusted risk of PC was higher for men with a paternal history of PC (OR = 2.31; 95%CI: 1.70-3.14), personal history of prostatitis (OR = 2.30; 95%CI: 1.44-3.70), benign prostatic hyperplasia (OR = 2.29; 95%CI: 1.79-2.93), being overweight (vs. normal; OR = 1.24; 95%CI: 0.99-1.55) or obese (vs. normal; OR = 1.44; 95%CI: 1.09-1.89), having reported more than seven sexual partners in a lifetime (vs. < 3 partners; OR = 2.00; 95%CI: 1.49-2.68), and having reported more than 5 orgasms a month prior to PC diagnosis (vs. ≤3 orgasms; OR = 1.59; 95%CI: 1.18-2.15). PC risk was lower for men whose timing of puberty was later than their peers (vs. same as peers; OR = 0.75; 95%CI: 0.59-0.97), and a smaller risk reduction of was observed in men whose timing of puberty was earlier than their peers (vs. same as peers; OR = 0.85; 95%CI: 0.61-1.17). No associations were found between PC risk and vertex balding, erectile function, acne, circumcision, vasectomy, asthma or diabetes. These results support a role for adult body size, sexual activity, and adolescent sexual development in PC development.

Occupation, industry, and the risk of prostate cancer: a case-control study in Montréal, Canada

BACKGROUND

Age, family history and ancestry are the only recognized risk factors for prostate cancer (PCa) but a role for environmental factors is suspected. Due to the lack of knowledge on the etiological factors for PCa, studies that are both hypothesis-generating and confirmatory are still needed. This study explores relationships between employment, by occupation and industry, and PCa risk.

METHODS

Cases were 1937 men aged ≤75 years with incident PCa diagnosed across Montreal French hospitals in 2005-2009. Controls were 1994 men recruited concurrently from electoral lists of French-speaking Montreal residents, frequency-matched to cases by age. In-person interviews elicited occupational histories. Unconditional logistic regression estimated odds ratios (OR) and 95 % confidence intervals (CI) for the association between employment across 696 occupations and 613 industries and PCa risk, adjusting for potential confounders. Multinomial logistic models assessed risks by PCa grade. Semi-Bayes (SB) adjustment accounted for the large number of associations evaluated.

RESULTS

Consistently positive associations-and generally robust to SB adjustment-were found for occupations in forestry and logging (OR 1.9, 95 % CI: 1.2-3.0), social sciences (OR 1.6, 95 % CI: 1.1-2.2) and for police officers and detectives (OR: 1.8, 95 % CI 1.1-2.9). Occupations where elevated risk of high grade PCa was found included gasoline station attendants (OR 4.3, 95 % CI 1.8-10.4) and textile processing occupations (OR 1.8, 95 % CI 1.1-3.2). Aside from logging, industries with elevated PCa risk included provincial government and financial institutions. Occupations with reduced risk included farmers (OR 0.6, 95 % CI 0.4-1.0) and aircraft maintenance workers (OR 0.1, 95 % CI 0.0-0.7).

CONCLUSIONS

Excess PCa risks were observed across several occupations, including predominantly white collar workers. Further analyses will focus on specific occupational exposures.

Diagnostic and Therapeutic Strategies for Prostate Cancer

Prostate cancer (PC) is a major disease that affects men's health worldwide. It is the second most common form of cancer in men, surpassed only by nonmelanoma skin cancers such as basal and squamous cell carcinomas. Diagnostic strategies with population screening for prostate cancer using prostate-specific antigen (PSA) has been surrounded with controversy and debated intensively ever since the PSA protein was first purified in 1979 by Wang et al. At the same time, advances in diagnostic imaging, surgery, radiation, and chemotherapy have increased the opportunity to effectively diagnose, treat, and manage PC. Given the sheer burden of PC disease in Denmark and worldwide, new and innovative strategies for cancer diagnosis and care are needed. This article is a short review of current diagnostic and therapeutic strategies for the care and management of prostate cancer in Denmark.

Low-dose aspirin or other nonsteroidal anti-inflammatory drug use and prostate cancer risk: a nationwide study

PURPOSE

Increasing evidence suggests that aspirin use may protect against prostate cancer. In a nationwide case-control study, using Danish high-quality registry data, we evaluated the association between the use of low-dose aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) and the risk of prostate cancer.

METHODS

We identified 35,600 patients (cases) with histologically verified prostate cancer during 2000-2012. Cases were matched to 177,992 population controls on age and residence by risk-set sampling. Aspirin and nonaspirin NSAID exposure was defined by type, estimated dose, duration, and consistency of use. We used conditional logistic regression to estimate odds ratios (ORs), with 95 % confidence intervals (CIs), for prostate cancer associated with low-dose aspirin (75-150 mg) or nonaspirin NSAID use, adjusted for potential confounders.

RESULTS

Use of low-dose aspirin was associated with an OR for prostate cancer of 0.94 (95 % CI 0.91-0.97). Slightly lower ORs were seen with increasing cumulative amount, duration, and consistency of low-dose aspirin use (continuous use, ≥5 years: OR 0.89; 95 % CI 0.82-0.97; ≥10 years: OR 0.86; 95 % CI 0.70-1.06). Nonaspirin NSAID use was associated with a slightly increased OR for prostate cancer (1.13; 95 % CI 1.10-1.15); however, this association was confined to localized disease and did not vary materially with amount, duration, or consistency of nonaspirin NSAID use.

CONCLUSIONS

Our study indicates that long-term, consistent low-dose aspirin use may provide modest protection against prostate cancer. The slightly increased risk of only localized prostate cancer with nonaspirin NSAID use suggests a noncausal explanation of the observed association.

The clinical effectiveness and cost-effectiveness of the PROGENSA® prostate cancer antigen 3 assay and the Prostate Health Index in the diagnosis of prostate cancer: a systematic review and economic evaluation

BACKGROUND

There is no single definitive test to identify prostate cancer in men. Biopsies are commonly used to obtain samples of prostate tissue for histopathological examination. However, this approach frequently misses cases of cancer, meaning that repeat biopsies may be necessary to obtain a diagnosis. The PROGENSA(®) prostate cancer antigen 3 (PCA3) assay (Hologic Gen-Probe, Marlborough, MA, USA) and the Prostate Health Index (phi; Beckman Coulter Inc., Brea, CA, USA) are two new tests (a urine test and a blood test, respectively) that are designed to be used to help clinicians decide whether or not to recommend a repeat biopsy.

OBJECTIVE

To evaluate the clinical effectiveness and cost-effectiveness of the PCA3 assay and the phi in the diagnosis of prostate cancer.

DATA SOURCES

Multiple publication databases and trial registers were searched in May 2014 (from 2000 to May 2014), including MEDLINE, EMBASE, The Cochrane Library, ISI Web of Science, Medion, Aggressive Research Intelligence Facility database, ClinicalTrials.gov, International Standard Randomised Controlled Trial Number Register and World Health Organization International Clinical Trials Registry Platform.

REVIEW METHODS

The assessment of clinical effectiveness involved three separate systematic reviews, namely reviews of the analytical validity, the clinical validity of these tests and the clinical utility of these tests. The assessment of cost-effectiveness comprised a systematic review of full economic evaluations and the development of a de novo economic model.

SETTING

The perspective of the evaluation was the NHS in England and Wales.

PARTICIPANTS

Men suspected of having prostate cancer for whom the results of an initial prostate biopsy were negative or equivocal.

INTERVENTIONS

The use of the PCA3 score or phi in combination with existing tests (including histopathology results, prostate-specific antigen level and digital rectal examination), multiparametric magnetic resonance imaging and clinical judgement.

RESULTS

In addition to documents published by the manufacturers, six studies were identified for inclusion in the analytical validity review. The review identified issues concerning the precision of the PCA3 assay measurements. It also highlighted issues relating to the storage requirements and stability of samples intended for analysis using the phi assay. Fifteen studies met the inclusion criteria for the clinical validity review. These studies reported results for 10 different clinical comparisons. There was insufficient evidence to enable the identification of appropriate test threshold values for use in a clinical setting. In addition, the implications of adding either the PCA3 assay or the phi to clinical assessment were not clear. Furthermore, the addition of the PCA3 assay or the phi to clinical assessment plus magnetic resonance imaging was not found to improve discrimination. No published papers met the inclusion criteria for either the clinical utility review or the cost-effectiveness review. The results from the cost-effectiveness analyses indicated that using either the PCA3 assay or the phi in the NHS was not cost-effective.

LIMITATIONS

The main limitations of the systematic review of clinical validity are that the review conclusions are over-reliant on findings from one study, the descriptions of clinical assessment vary widely within reviewed studies and many of the reported results for the clinical validity outcomes do not include either standard errors or confidence intervals.

CONCLUSIONS

The clinical benefit of using the PCA3 assay or the phi in combination with existing tests, scans and clinical judgement has not yet been confirmed. The results from the cost-effectiveness analyses indicate that the use of these tests in the NHS would not be cost-effective.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014009595.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Dietary Total Antioxidant Capacity is Inversely Associated with Prostate Cancer Aggressiveness in a Population-Based Study

The purpose of this study was to determine the relationship between total antioxidant capacity (TAC) from diet and supplements and prostate cancer aggressiveness among 855 African Americans (AA) and 945 European Americans (EA) in the North Carolina-Louisiana Prostate Cancer Project (PCaP). Cases were classified as either high aggressive, low aggressive, or intermediate aggressive. TAC was calculated from the vitamin C equivalent antioxidant capacity of 42 antioxidants measured via food frequency questionnaire. EA reported greater dietary TAC from diet and supplements combined (P < 0.0001). In both minimally and fully adjusted logistic regression models, TAC from diet and supplements combined was associated with a reduced odds of high aggressive prostate cancer in all men, AA and EA: odds ratios for highest vs. lowest level (>1500 vs. <500 mg vitamin C equivalent/day): 0.31 [95% confidence interval (CI): 0.15, 0.67; P-trend < 0.01], 0.28 (95% CI: 0.08, 0.96; P-trend < 0.001), and 0.36 (95% CI: 0.15, 0.86; P-trend = 0.58), respectively. These associations did not appear to differ between AA and EA. These data suggest that greater intake of antioxidants is associated with less aggressive prostate cancer. Additional research is needed to confirm these results and determine the underlying mechanisms.

Intake of dietary antioxidants is inversely associated with biomarkers of oxidative stress among men with prostate cancer

Prostate cancer is the most common non-cutaneous cancer and the second leading cause of cancer-related mortality among men in the USA. Growing evidence suggests that oxidative stress is involved in the development and progression of prostate cancer. In this study, the association between antioxidants from diet and supplements and biomarkers of oxidative stress in blood (n 278), urine (n 298) and prostate tissue (n 55) were determined among men from the North Carolina-Louisiana Prostate Cancer Project. The association between antioxidant intake and oxidative stress biomarkers in blood and urine was determined using linear regression, adjusting for age, race, prostate cancer aggressiveness and smoking status. Greater antioxidant intake was found to be associated with lower urinary 8-isoprostane concentrations, with a 10% increase in antioxidant intake corresponding to an unadjusted 1·1% decrease in urinary 8-isoprostane levels (95% CI -1·7, -0·3%; P value<0·01) and an adjusted 0·6% decrease (95% CI -1·4, 0·2%; P value=0·16). In benign prostate tissue, thioredoxin 1 was inversely associated with antioxidant intake (P=0·02). No significant associations were found for other blood or urinary biomarkers or for malignant prostate tissue. These results indicate that antioxidant intake may be associated with less oxidative stress among men diagnosed with prostate cancer.

Viral infections in prostate carcinomas in Chilean patients

BACKGROUND

A few viruses have been detected in prostate cancer, however their role in the development of this malignancy has not been determined. The aim of this study was to analyze the presence and functionality of human papillomavirus (HPV) and polyomaviruses (BKPyV and JCPyV) in prostate carcinomas in Chilean patients.

METHODS

Sixty-nine primary prostate carcinomas were analyzed for the presence of HPV, BKPyV and JCPyV using standard polymerase chain reaction protocols. In addition, when samples were positive for HPyV, large T antigen (TAg) transcripts were analyzed using reverse transcriptase PCR.

RESULTS

HPV and JCPyV were not detected in any specimens (0/69, 0 %); whereas, BKPyV was detected in 6/69 PCas (8.7 %). We did not find a statistically significant association between the presence of BKPyV and age (p = 0.198) or Gleason score (p = 0.268). In addition, 2/6 (33 %) BKPyV positive specimens showed detectable levels of TAg transcripts.

CONCLUSIONS

There was no association between HPV or JCPyV presence and prostate cancer development. The presence of BKPyV in a small subset of prostate carcinomas in Chilean patients could indicate that this virus plays a potential role in prostate cancer development and requires further investigation.

Thioredoxin 1 in Prostate Tissue Is Associated with Gleason Score, Erythrocyte Antioxidant Enzyme Activity, and Dietary Antioxidants

Background. Prostate cancer is the most common noncutaneous cancer and second leading cause of cancer-related mortality in men in the US. Growing evidence suggests that oxidative stress is involved in prostate cancer. Methods. In this study, thioredoxin 1 (Trx 1), an enzyme and subcellular indicator of redox status, was measured in prostate biopsy tissue from 55 men from the North Carolina-Louisiana Prostate Cancer Project. A pathologist blindly scored levels of Trx 1. The association between Trx 1 and the Gleason score, erythrocyte antioxidant enzyme activity, and dietary antioxidant intake was determined using Fisher's exact test. Results. Trx 1 levels in benign prostate tissue in men with incident prostate cancer were positively associated with the Gleason score (P = 0.01) and inversely associated with dietary antioxidant intake (P = 0.03). In prostate cancer tissue, Trx 1 levels were associated with erythrocyte glutathione peroxidase activity (P = 0.01). No association was found for other erythrocyte enzymes. Greater Gleason score of malignant tissue corresponds to a greater difference in Trx 1 levels between malignant and benign tissue (P = 0.04). Conclusion. These results suggest that the redox status of prostate tissue is associated with prostate cancer grade and both endogenous and exogenous antioxidants.

Association between EHBP1 rs721048(A>G) polymorphism and prostate cancer susceptibility: a meta-analysis of 17 studies involving 150,678 subjects

Background

EHBP1 rs721048(A) was first identified as a prostate cancer (PCa) risk in Caucasians by genome-wide association study, but subsequent replication studies involving Caucasian and other ethnicities did not produce consistent results. The aim of this study was to obtain a more definite association between rs721048(A) and PCa risk.

Methods

We comprehensively searched several databases updated to September 2014, including PubMed, Web of Science, EBSCO, and Google Scholar. Two authors independently screened and reviewed the eligibility of each study. The quality of the included studies was assessed by the Newcastle–Ottawa scale. The association of rs721048(A) and PCa risk was assessed by pooling odds ratios (ORs) with 95% confidence intervals (CIs).

Results

A total of 17 studies, including 48,135 cases and 102,543 controls, published between 2008 and 2014 were included in the meta-analysis. Overall, the pooled analysis demonstrated that rs721048(A) was significantly associated with the risk of PCa under the allele model (OR=1.14, 95% CI=1.11–1.17, P=0.000). Subgroup analysis based on ethnicity revealed a significant association between rs721048(A) and PCa in Caucasian (OR=1.14, 95% CI=1.11–1.16, P=0.000), African descent (OR=1.11, 95% CI=1.01–1.23, P=0.025), and Asian (OR=1.35, 95% CI=1.12–1.64, P=0.002).

Conclusion

Our results provided strong evidence that rs721048(A) could be a risk factor for PCa.

A critical review of the epidemiology of Agent Orange/TCDD and prostate cancer

To inform risk assessment and regulatory decision-making, the relationship between 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and prostate cancer requires clarification. This article systematically and critically reviews the epidemiologic evidence on the association between exposure to TCDD or Agent Orange, a TCDD-contaminated herbicide used during the Vietnam War, and prostate cancer risk. Articles evaluated include 11 studies of three cohorts, four case-control or cross-sectional studies, and three case-only studies of military veterans with information on estimated Agent Orange or TCDD exposure; 13 studies of seven cohorts, one case-control study, and eight proportionate morbidity or mortality studies of Vietnam veterans without information on Agent Orange exposure; 11 cohort studies of workers with occupational exposure to TCDD; and two studies of one community cohort with environmental exposure to TCDD. The most informative studies, including those of Vietnam veterans involved in Agent Orange spraying or other handling, herbicide manufacturing or spraying workers with occupational TCDD exposure, and community members exposed to TCDD through an industrial accident, consistently reported no significant increase in prostate cancer incidence or mortality. Only some potentially confounded studies of Vietnam veterans compared with the general population, studies with unreliable estimates of Agent Orange exposure, and analyses of selected subgroups of Vietnam veterans reported positive associations. Overall, epidemiologic research offers no consistent or convincing evidence of a causal relationship between exposure to Agent Orange or TCDD and prostate cancer. More accurate exposure assessment is needed in large epidemiologic studies to rule out a causal association more conclusively.

Genetic variants of chemokine CCL2 and chemokine receptor CCR2 genes and risk of prostate cancer

Chemokines and their receptors acts as mediators of migration of immune cells to the site of inflammation and deregulated inflammatory response is associated with increased risk of cancer. We performed a case-control study to analyze the frequencies of CCL2 (I/D, rs3917887), -2518 (A > G, rs1024611), and CCR2 (G > A, rs1799864) polymorphisms for prostate cancer (PCa) risk. In this hospital-based case-control study, histologically confirmed 195 PCa patients and 250 unrelated healthy controls of similar ethnicity were genotyped by PCR-RFLP. The result showed that heterozygous ID (odds ratio (OR) = 1.71; p = 0.010) carrier genotype of CCL2 gene were at increased risk for developing PCa. Variant allele D carriers (ID + DD) demonstrated a 1.67-fold increased risk (OR = 1.67; p = 0.010), suggesting a dominant effect model involved in PCa risk. Similarly, variant allele D of CCL2 gene also had a higher risk (OR = 1.53; p = 0.040) for developing PCa. High risk to PCa was also observed with respect to diplotypes, I-G (OR = 1.83; Bonferroni corrected p value (P c) = 0.004) and D-A (OR = 2.11; P c = 0.004) of CCL2 I/D and -2518 (A > G). In association of genotypes with clinic-pathological grade of tumor, homozygous DD (OR = 7.40; P c = 0.042) and variant allele carrier ID + DD (OR = 2.42; P c = 0.036) genotypes of CCL2 gene conferred risk in high Gleason grade tumor of PCa. We observed a significantly enhanced risk for PCa due to interaction between CCL2 I/D, -2518 (A > G), and CCR2 (G > A) genotypes. However, -2518 (A > G) and CCR2 V64I (G > A) gene polymorphisms were not significantly associated with PCa risk. Our results supported that CCL2 I/D gene variant contribute to the susceptibility and clinic-pathological characteristic of PCa and could be considered as an important risk factor for this malignancy in North Indian men.

A DNA hypermethylation profile reveals new potential biomarkers for prostate cancer diagnosis and prognosis

BACKGROUND

DNA hypermethylation has emerged as a novel molecular biomarker for the evaluation of prostate cancer diagnosis and prognosis. Defining the specific gene hypermethylation profile for prostate cancer could involve groups of genes that specifically discriminate patients with indolent and aggressive tumors.

METHODS

Genome-wide methylation analysis was performed on 83 tumor and 10 normal prostate samples using the GoldenGate Methylation Cancer Panel I (Illumina, Inc.). All clinical stages of disease were considered.

RESULTS

We found 41 genes hypermethylated in more than 20% of the tumors analyzed (P < 0.01). Of these, we newly identified GSTM2 and PENK as being genes that are hypermethylated in prostate cancer and that were simultaneously methylated in 40.9% of the tumors analyzed. We also identified panels of genes that are more frequently methylated in tumor samples with clinico-pathological indicators of poor prognosis: a high Gleason score, elevated Ki-67, and advanced disease. Of these, we found simultaneous hypermethylation of CFTR and HTR1B to be common in patients with a high Gleason score and high Ki-67 levels; this might indicate the population at higher risk of therapeutic failure. The DNA hypermethylation profile was associated with cancer-specific mortality (log-rank test, P = 0.007) and biochemical recurrence-free survival (log-rank test, P = 0.0008).

CONCLUSIONS

Our findings strongly indicate that epigenetic silencing of GSTM2 and PENK is a common event in prostate cancer that could be used as a molecular marker for prostate cancer diagnosis. In addition, simultaneous HTR1B and CFTR hypermethylation could help discriminate aggressive from indolent prostate tumors.

Autophagy as a modulator and target in prostate cancer

Autophagy, or 'self-eating', is an adaptive process that enables cells to cope with metabolic, toxic, and even infectious stressors. Although the adaptive capability of autophagy is generally considered beneficial, autophagy can also enhance nutrient utilization and improve growth characteristics of cancer cells. Moreover, autophagy can promote greater cellular robustness in the context of therapeutic intervention. In advanced prostate cancer, preclinical data provide evidence that autophagy facilitates both disease progression and therapeutic resistance. Notably, androgen deprivation therapy, taxane-based chemotherapy, targeted kinase inhibition, and nutrient restriction all induce significant cellular distress and, subsequently, autophagy. Understanding the context-dependent role of autophagy in cancer development and treatment resistance has the potential to improve current treatment of advanced prostate cancer. Indeed, preclinical studies have shown that the pharmacological inhibition of autophagy (with agents including chloroquine, hydroxychloroquine, metformin, and desmethylclomipramine) can enhance the cell-killing effect of cancer therapeutics, and a number of these agents are currently under investigation in clinical trials. However, many of these autophagy modulators are relatively nonspecific, and cytotoxicity in noncancerous tissues is still a concern. Moving forward, refinement of autophagy modulation is needed.

Prostate cancer risk and nonsteroidal antiinflammatory drug use in the Finnish prostate cancer screening trial

Background:

The association between nonsteroidal antiinflammatory drugs (NSAIDs) and prostate cancer risk remains controversial. We examined the risk among NSAID users in 78 615 men in the Finnish Prostate Cancer Screening Trial.

Methods:

We obtained information on NSAID prescription usage from Finnish nationwide prescription database and on over-the-counter use by a questionnaire. Prostate cancer cases were identified from the Finnish Cancer Registry.

Results:

Prostate cancer risk was elevated among current NSAID prescription users irrespective of screening (hazard ratio (HR)=1.45, confidence interval (95% CI)=1.33–1.59 and HR=1.71, 95% CI=1.58–1.86 in the screening and control arm, respectively), but not for previous use of NSAIDs. The risk increase was similar among coxib and acetaminophen current users, and stronger for metastatic prostate cancer (HR=2.41, 95% CI=1.59–3.67 and HR=3.44, 95% CI=2.60–4.55 in the screening and control arm, respectively). Previous use of NSAIDs, aspirin use and over-the-counter NSAID usage were not associated with prostate cancer.

Conclusions:

Differing association for current and previous use suggests that the risk increase is unlikely to be directly caused by the medication, but may be due to the conditions indicating NSAID prescription usage, such as symptoms of undiagnosed prostate cancer. To reduce inconsistency between the study outcomes, future epidemiological studies on NSAID use and prostate cancer risk should assess the indications for NSAID usage.

Association of C-peptide and leptin with prostate cancer incidence in the Health Professionals Follow-up Study

PURPOSE

Hyperinsulinemia is hypothesized to influence prostate cancer risk. Thus, we evaluated the association of circulating C-peptide, which is a marker of insulin secretion, and leptin, which is secreted in response to insulin and influences insulin sensitivity, with prostate cancer risk.

METHODS

We identified prostate cancer cases (n = 1,314) diagnosed a mean of 5.4 years after blood draw and matched controls (n = 1,314) in the Health Professionals Follow-up Study. Plasma C-peptide and leptin concentrations were measured by ELISA. Odds ratios (ORs) and 95 % confidence intervals (CI) were estimated taking into account the matching factors age and history of a PSA test before blood draw and further adjusting for body mass index, diabetes, and other factors.

RESULTS

Neither C-peptide (quartile [Q]4 vs. Q1: OR 1.05, 95 % CI 0.82-1.34, p-trend = 0.95) nor leptin (Q4 vs. Q1: OR 0.85, 95 % CI 0.65-1.12, p-trend = 0.14) was associated with prostate cancer risk. Further, neither was associated with risk of advanced or lethal disease (n = 156 cases; C-peptide: Q4 vs. Q1, OR 1.18, 95 % CI 0.69-2.03, p-trend = 0.78; leptin: Q4 vs. Q1, OR 0.74, 95 % CI 0.41-1.36, p-trend = 0.34).

CONCLUSIONS

In this large prospective study, circulating C-peptide and leptin concentrations were not clearly associated with risk of prostate cancer overall or aggressive disease. Well into the PSA era, our findings do not appear to be supportive of the hypothesis that hyperinsulinemia influences risk of total or aggressive prostate cancer.

Dietary antioxidants and prostate cancer: a review

Prostate cancer is the most common noncutaneous cancer in men in the United States. Several studies have examined the relationship between prostate cancer and antioxidants; however, the results of these studies are inconsistent. This article provides a systematic review of studies on prostate cancer and antioxidant intake from diet and supplements. Tea and coffee appear to offer protection against advanced prostate cancer. Different forms of vitamin E appear to exert different effects on prostate cancer, with alpha-tocopherol potentially increasing and gamma-tocopherol potentially decreasing risk of the disease. There is no strong evidence for a beneficial effect of selenium, vitamin C, or beta-carotene, whereas lycopene appears to be negatively associated with risk of the disease. The effect of dietary antioxidants on prostate cancer remains undefined and inconclusive, with different antioxidants affecting prostate cancer risk differentially. Further studies are needed to clarify the relationship between antioxidants and prostate cancer risk and to delineate the underlying mechanisms.

Case-control study on perfluorinated alkyl acids (PFAAs) and the risk of prostate cancer

Perfluorinated alkyl acids (PFAAs) are emerging environmental contaminants. Possible health effects for humans include increased risk for cancer but the knowledge is limited. In this study serum concentrations of certain perfluorinated sulfonates (PFHxS and PFOS) and carboxylates (PFOA, PFNA, PFDA, PFUnDA) were analyzed among 201 cases with prostate cancer and 186 population based control subjects. All blood samples were collected during 2007-2011 and no case had been treated with radio- or chemotherapy before enrolment in the study. The blood concentrations did not differ statistically significant between cases and controls except for PFDA with higher concentration among the cases (p=0.03). Analyses based on Gleason score and prostate specific antigen (PSA) level did not change the results. Heredity was a risk factor for prostate cancer yielding odds ratio (OR)=1.8, 95% confidence interval (CI)=1.01-3.1. The analyzed PFAAs yielded statistically significant higher ORs in cases with a first degree relative reporting prostate cancer, e.g., PFOA gave OR=2.6, 95% CI=1.2-6.0 and PFOS gave OR=2.7, 95% CI=1.04-6.8. The results showed a higher risk for prostate cancer in cases with heredity as a risk factor. In further studies interaction between gene and environment should be considered.

Cancer incidence in ethnic German migrants from the Former Soviet Union in comparison to the host population

AIM

To investigate cancer incidence patterns among ethnic German migrants (Aussiedler) from the Former Soviet Union, a large migrant group in Germany, in comparison to autochthonous Saarland population over a 20 year observation period.

METHODS

Data were obtained from a cohort of Aussiedler residing in the federal state of Saarland (n=18,619). Cancer incidence and vital status were ascertained through record linkage with the Saarland Cancer Registry and local population registries.

RESULTS

During the follow up period from 1990 to 2009 we observed 638 incident diagnoses of malignant neoplasms (except non-melanoma skin cancer). The overall standardized incidence ratio (SIR) was 0.98 (95% confidence interval 0.92, 1.04). However, site-specific SIRs revealed great variation. Stomach cancer incidence was significantly higher among Aussiedler. Lung cancer was elevated for males, but lower among females. Additionally, diagnoses for colorectal cancer among males were significantly lower. Age-standardized rates (ASRs) over time show not all cancer rates of Aussiedler attenuate as expected to Saarland rates. For example, lung and prostate cancer incidence rates show increasing disparity from Saarland rates and female breast cancer incidence develops in parallel. Furthermore, ASR for overall cancer incidence of Aussiedler shows a yearly decrease (p=0.06) whereas Saarland rates remain stable.

DISCUSSION

Aussiedler incidence rates reflect incidence pattern observed in their countries of origin.

Smoking and prostate cancer in a multi-ethnic cohort

BACKGROUND

Prostate cancer (PCa) and smoking-related morbidity disproportionately burdens African American (AA) men. Smoking is associated with high-grade PCa and incidence, but few studies have focused on AA men. This study aims to determine the effect of tobacco-use on odds of PCa and of high-grade PCa in a population of predominantly AA men.

METHODS

This is a cross-sectional study evaluating smoking and PCa status in men with incident PCa and screened healthy controls. Altogether, 1,085 men (527 cases and 558 controls), age ≥ 40 years were enrolled through outpatient urology clinics in two US cities from 2001 to 2012. Validated questionnaires were used to gather clinical and socioeconomic data.

RESULTS

The cases and controls were predominantly AA (79.9% and 71.3%, respectively, P = 0.01). AA men smoked more frequently (53.4% vs. 47.9%, P < 0.001) and quit less frequently than European American (EA) men (31.5% vs. 40.4%, P = 0.01). AA heavy smokers had increased odds of PCa diagnosis (OR 2.57, 95% CI 1.09, 6.10) and high-grade cancer (OR 1.89, 95% CI 1.03, 3.48) relative to never smokers and light smokers. Among AAs, heavy smokers had lower odds of NCCN low PCa recurrence risk stratification. AA former smokers had a trend for increased odds of high-grade cancer compared to never smokers. The associations between smokings, cancer diagnosis and cancer grade did not reach statistical significance in EA men.

CONCLUSION

We found ethnic differences in smoking behavior. Heavy smoking is associated with increased odds of PCa and of higher Gleason grade in AA men.

Polymorphisms in genes related to inflammation, NSAID use, and the risk of prostate cancer among Danish men

The etiology of prostate cancer (PC) remains mostly unknown, but increasing evidence suggests that chronic inflammation in the prostate is associated with an increased risk of PC. Epidemiological studies have suggested that use of nonsteroidal anti-inflammatory drugs (NSAIDs) may protect against PC. Inborn variations in genes involved in the inflammatory response may modulate the risk of PC and interact with NSAIDs. The aims of this study were 1) to evaluate whether polymorphisms and haplotypes of the inflammation-related genes COX-2, Il1B, NFKB1, and PPARG are associated with risk of PC; 2) to investigate gene-environment interactions between polymorphisms and NSAID use; and 3) to examine whether the studied polymorphisms were associated with the aggressiveness of PC. The study population consisted of 370 cases of PC and 370 risk-set matched (age) controls nested within the prospective Danish "Diet, Cancer, and Health" cohort. Carriers of the variant deletion allele of NFKB1 -94ins/delATTG had a tendency toward a reduced risk of PC (incidence rate ratio (IRR), 0.73; 95% confidence interval (CI) 0.52-1.04). A lowered risk for PC was also found for carriers of variant allele NFKB1 -94ins/delATTG among non-users of NSAIDs (IRR 0.68; 95% CI 0.47-0.99), for non-aggressive disease (IRR 0.64; 95% CI 0.42-0.99), and among men with a body mass index above 30 kg/m(2) (IRR 0.56; 95% CI 0.27-1.16), although the latter estimate was based on small numbers. A similar pattern was seen for the variant C allele of the COX-2 +8473T→C polymorphism. No apparent association with PC was observed for the other studied polymorphisms. Our study did not indicate that chronic inflammation is a major risk factor for aggressive PC.

Sun exposure and the risk of prostate cancer in the Singapore Prostate Cancer Study: a case-control study

BACKGROUND

Most of the epidemiology studies on the effects of sun exposure and prostate cancer were conducted among the temperate countries of North America and Europe. Little is known about the influence on Asian populations. The purpose of current study was to evaluate any association of sun exposure with risk of prostate cancer in Chinese, Malays and Indians who reside in the tropics.

METHODS

The Singapore Prostate Cancer Study is a hospital-based case-control study of 240 prostate cancer incident cases and 268 controls conducted in Singapore between April 2007 and May 2009. Detailed information on outdoor activities in the sun, skin colour, sun sensitivity and other possible risk factors were collected in personal interviews. Cases were further classified by Gleason scores and TNM staging. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using unconditional logistic regression analysis, adjusted for age, ethnicity, education, family history of any cancers, BMI and skin colour.

RESULTS

We found that prostate cancer risk was increased in subjects with black/dark-brown eyes (OR 5.88, 95%CI 3.17-10.9), darker skin colour e.g. tan/dark brown/black (OR 7.62, 95%CI 3.41-17.0), frequent sunburn in lifetime (OR 4.30, 95%CI 1.7-11.2) and increased general sun exposure in adulthood per week (OR 2.03, 95%CI 1.09-3.81). The increased risk was consistent for high grade tumours and advanced stage prostate cancers.

CONCLUSION

The findings from this study suggest that excessive sun exposure is a risk factor for prostate cancer in Asians.

Prostate cancer in Denmark 1978-2009--trends in incidence and mortality

BACKGROUND

The incidence of prostate cancer (PC) has increased during the last 15 years in Denmark, whereas the mortality has remained largely unchanged. This register study aimed to investigate the trends in PC incidence and mortality in Denmark 1978-2009 with special focus on the recent 15 years.

MATERIAL AND METHODS

From the nationwide Danish Cancer Registry and Register of Causes of Death, we obtained information on all cases of PC and all deaths in Denmark during 1978-2009. Age-standardised (World Standard Population) incidence and mortality rates were computed for five-year calendar periods (1978-2007) and a two-year calendar period (2008-2009). Trends in incidence rates were estimated for specific age groups, birth cohorts, and clinical stage.

RESULTS

The age-standardised incidence rate of PC increased from 29.2 per 100,000 person-years in 1978-1982 to 76.2 per 100,000 person-years in 2008-2009. The incidence increase began primarily in the mid-1990s. The corresponding mortality rates of PC remained largely unchanged during the entire study period; around 19 per 100,000 person-years. The incidence increase was most pronounced among men aged 60 + years. A clear pattern was also seen for selected birth cohorts, with increasing incidence rates among the youngest cohorts, and the highest relative increase in age-specific incidence rates was seen among men born between 1943 and 1947. The distribution of stage changed from 1998, with an increasing proportion of PC patients with localised disease.

CONCLUSION

The observed increase in PC incidence during the period 1993-2009 in Denmark may be attributed primarily to increasing unsystematic use of prostate specific antigen (PSA) testing. The mortality rates remained stable during the same period suggesting that there is not yet any major influence of intensified PSA screening and more frequent use of curatively intended therapy on the overall prognosis of PC.

Synergistic killing effect of chloroquine and androgen deprivation in LNCaP cells

Modulation of autophagy is a new paradigm in cancer therapeutics. Recently a novel function of chloroquine (CLQ) in inhibiting degradation of autophagic vesicles has been revealed, which raises the question whether CLQ can be used as an adjuvant in targeting autophagic pro-survival mechanism in prostate cancer (PCa). We previously showed that autophagy played a protective role during hormone ablation therapy, in part, by consuming lipid droplets in PCa cells. In addition, blocking autophagy by genetic and pharmacological means in the presence of androgen deprivation caused cell death in PCa cells. To further investigate the importance of autophagy in PCa survival and dissect the role of CLQ in PCa death, we treated hormone responsive LNCaP cells with CLQ in combination with androgen deprivation. We observed that CLQ synergistically killed LNCaP cells during androgen deprivation in a dose- and time-dependent manner. We further confirmed that CLQ inhibited the maturation of autophagic vesicles and decreased the cytosolic ATP. Moreover, CLQ induced nuclear condensation and DNA fragmentation, a hallmark of apoptosis, in androgen deprived LNCaP cells. Taken together, our finding suggests that CLQ may be an useful adjuvant in hormone ablation therapy to improve the therapeutic efficacy.

Prostate cancer in Germany among migrants from the Former Soviet Union

Background

In Germany, prostate cancer is the leading cause of cancer and the third leading cause of death from cancer in males. We investigate prostate cancer in Gernmany among migrants from the Former Soviet Union (FSU) and compare them to indigenous German population with regard to prostate cancer incidence, mortality and longitudinal effects.

Methods

Data were obtained from two migrant cohorts residing in the federal states of North Rhine Westphalia (n=34,393) and Saarland (n=18,619). Vital status was ascertained through local population registries. Causes of death were obtained from the federal statistical office or from local health authorities. Cancer incidence of the Saarland cohort was derived from the Saarland Cancer Registry using record linkage.

Results

From 1990 to 2005 we observed 3360 deaths of which 28 were due to prostate cancer. In the Saarland cohort 35 men were diagnosed with prostate cancer during the respective period. Migrants had lower prostate cancer incidence (SIR 0.74 (95% CI: 0.52–1.03)) and mortality (SMR 0.57 (95% CI: 0.38–0.83)) compared to the German population. Multivariate analysis showed a strong age effect on incidence meaning young migrants (below age 60) were diagnosed significantly more often with prostate cancer compared to Germans of the same age. However, mortality did not show any effects.

Discussion

Lower prostate cancer mortality and incidence among migrants may reflect an ongoing situation in the FSU. Additionally, longitudinal analysis did not reveal convergence of migrant prostate cancer to German rates as expected from lifestyle driven cancer sites. Therefore, our results support the hypothesis of a genetic effect on prostate cancer risk.

Screening for prostate cancer: an updated Cochrane systematic review

OBJECTIVE

•To determine whether screening for prostate cancer reduces prostate cancer-specific mortality, impact on all-cause mortality and patient health-related quality of life.

MATERIALS AND METHODS

•An update to our 2006 Cochrane systematic review was performed by re-running an updated search of several databases, including MEDLINE and the Cochrane CENTRAL Register of Controlled Trials. • Articles were included if they were a randomized controlled trial (RCT) examining screening vs no screening for prostate cancer. Data was collected and analysed according to the methods outlined in the Cochrane Handbook for Systematic Reviews of Interventions.

RESULTS

•Five RCTs with a total of 341,351 participants were included in this updated Cochrane systematic review. All involved PSA testing, although the interval and threshold for further evaluation varied across trials. The age of participants was 50-74 years, with durations of patient follow-up of 7-15 years. •The methodological quality of three of the studies was assessed as posing a high risk of bias. •Meta-analysis of the five included studies indicated no statistically significant difference in prostate cancer-specific mortality between men randomized to screening and control [relative risk (RR) 0.95, 95% CI 0.85-1.07]. Sub-group analyses indicated that prostate cancer-specific mortality was not affected by age at which participants were screened. A pre-planned analysis of a 'core' age group of men aged 55-69 years from the largest RCT (European Randomised Study of Screening for Prostate Cancer) reported a significant 20% relative reduction in prostate cancer-specific mortality; (95% CI 0.65-0.98; absolute risk 0.71 per 1000 men). The number of men diagnosed with prostate cancer was significantly greater in men randomized to screening, compared with those randomized to control (RR 1.35, 95% CI 1.06-1.72). •Harms of screening included high rates of false-positive results for the PSA test, over-diagnosis and adverse events associated with transrectal ultrasonography guided biopsies such as infection, bleeding and pain.

CONCLUSIONS

•Prostate cancer screening did not significantly decrease all-cause or prostate cancer-specific mortality in a combined meta-analysis of five RCTs. •Any benefits from prostate cancer screening may take > 10 years to accrue; therefore, men who have a life expectancy of < 10-15 years should be informed that screening for prostate cancer is not beneficial and has harms.

[Constitutional risk factors in prostate cancer]

INTRODUCTION

The aim of this review is to update and divulge the main constitutional risk factors involved in the etiopathology of prostate cancer.

MATERIALS AND METHODS

Bibliographic review of the scientific literature on the constitutional risk factors associated with prostate cancer between 1985 and 2010, obtained from MedLine, CancerLit, Science Citation Index and Embase. The search profiles were Risk Factors, Genetic Factors, Genetic Polymorphisms, Genomics, Etiology, Epidemiology, Hormonal Factors, Endocrinology, Primary Prevention and Prostate Cancer.

RESULTS

The principal constitutional risk factors are: age (before the age of 50 years at least 0.7% of these neoplasms are diagnosed and between 75-85% are diagnosed after the age of 65 years), ethnic-racial and geographic (African Americans present the highest incidence rates, and the lowest are found in South East Asia), genetic, family and hereditary (family syndromes cover 13-26% of all prostate cancers, of which 5% are of autosomal dominant inheritance), hormonal (it is a hormone-dependent tumour), anthropometric (obesity increases the risk), perinatal, arterial hypertension and type 2 diabetes.

CONCLUSIONS

Constitutional risk factors play a very important role in the etiopathology of prostate cancer, especially age, ethnic-racial-geographic factors and genetic-family factors. We cannot know what percentage of these neoplasms are a result of constitutional factors, because our knowledge of these factors is currently lacking.

Hypertension is positively associated with prostate cancer development in the TRAP transgenic rat model

Epidemiological data on the relationship between hypertension and prostate cancer development are conflicting. To cast light on this question, we performed animal experiments using hybrid rats generated by crossing the spontaneously hypertensive rat (SHR) or its normotensive control Wistar Kyoto (WKY) rat with a transgenic rat for adenocarcinoma of prostate (TRAP) that features development of adenocarcinoma at high incidence by 15 weeks of age. The number of adenocarcinomatous foci in the lateral prostate of hypertensive (TRAP × SHR)F1 rats was demonstrated to be significantly increased compared with those of normotensive (TRAP × WKY)F1 rats. In the ventral prostate, increase of carcinoma foci was also observed but did not reach significance. The number of cancer foci showing microinvasion in (TRAP × SHR)F1 rats was higher than that of (TRAP × WKY)F1 rats, but again without significance, while treatment with prazosin, an anti-hypertensive agent, tended to decrease microinvasive carcinoma foci in both the ventral and lateral prostate. In conclusion, the present study provided additional evidence that high blood pressure is associated with prostate cancer risk.

Diet and prostate cancer: mechanisms of action and implications for chemoprevention

As one of the most prevalent cancers, prostate cancer has enormous public health significance and prevention strategies would attenuate its economic, emotional, physical and social impact. Until recently, however, we have had only modest information about risk factors for this disease, apart from the well-established characteristics of age, family history and place of birth. The large worldwide variation in the incidence of prostate cancer and the increased risk in migrants who move from low-risk to high-risk countries provide strong support for modifiable environmental factors, particularly diet, in its etiology. Thus, dietary agents have gained considerable attention as chemopreventive agents against prostate cancer. Dietary fat, red and processed meat, vitamin E, selenium, tomatoes, cruciforms and green tea have all been linked with the development and aggressiveness of prostate cancer, through a range of molecular mechanisms. The direction of future clinical trials lies in clarifying the effects of these agents and exploring the biological mechanisms responsible for the prevention of prostate cancer. However, owing to the short time period between diagnosis and treatment, conventional dietary intervention techniques are not always realistic. Until large randomized trials confirm the benefit of chemopreventive and dietary modifications, patients can be advised to pursue a diet and lifestyle that enhances overall health.

Identification of a novel prostate cancer biomarker, caveolin-1: Implications and potential clinical benefit

While prostate cancer is a common disease in men, it is uncommonly life-threatening. To better understand this phenomenon, tumor biologists have sought to elucidate the mechanisms that contribute to the development of virulent prostate cancer. The recent discovery that caveolin-1 (Cav-1) functions as an important oncogene involved in prostate cancer progression reflects the success of this effort. Cav-1 is a major structural coat protein of caveolae, specialized plasma membrane invaginations involved in multiple cellular functions, including molecular transport, cell adhesion, and signal transduction. Cav-1 is aberrantly overexpressed in human prostate cancer, with higher levels evident in metastatic versus primary sites. Intracellular Cav-1 promotes cell survival through activation of Akt and enhancement of additional growth factor pro-survival pathways. Cav-1 is also secreted as a biologically active molecule that promotes cell survival and angiogenesis within the tumor microenvironment. Secreted Cav-1 can be reproducibly detected in peripheral blood using a sensitive and specific immunoassay. Cav-1 levels distinguish men with prostate cancer from normal controls, and preoperative Cav-1 levels predict which patients are at highest risk for relapse following radical prostatectomy for localized disease. Thus, secreted Cav-1 is a promising biomarker in identifying clinically significant prostate cancer.

Identification of a novel prostate cancer biomarker, caveolin-1: Implications and potential clinical benefit

While prostate cancer is a common disease in men, it is uncommonly life-threatening. To better understand this phenomenon, tumor biologists have sought to elucidate the mechanisms that contribute to the development of virulent prostate cancer. The recent discovery that caveolin-1 (Cav-1) functions as an important oncogene involved in prostate cancer progression reflects the success of this effort. Cav-1 is a major structural coat protein of caveolae, specialized plasma membrane invaginations involved in multiple cellular functions, including molecular transport, cell adhesion, and signal transduction. Cav-1 is aberrantly overexpressed in human prostate cancer, with higher levels evident in metastatic versus primary sites. Intracellular Cav-1 promotes cell survival through activation of Akt and enhancement of additional growth factor pro-survival pathways. Cav-1 is also secreted as a biologically active molecule that promotes cell survival and angiogenesis within the tumor microenvironment. Secreted Cav-1 can be reproducibly detected in peripheral blood using a sensitive and specific immunoassay. Cav-1 levels distinguish men with prostate cancer from normal controls, and preoperative Cav-1 levels predict which patients are at highest risk for relapse following radical prostatectomy for localized disease. Thus, secreted Cav-1 is a promising biomarker in identifying clinically significant prostate cancer.