5-alpha-reductase activity and risk of prostate cancer among Japanese and US white and black males

Targeting Androgen, Thyroid Hormone, and Vitamin A and D Receptors to Treat Prostate Cancer

The nuclear hormone family of receptors regulates gene expression. The androgen receptor (AR), upon ligand binding and homodimerization, shuttles from the cytosol into the nucleus to activate gene expression. Thyroid hormone receptors (TRs), retinoic acid receptors (RARs), and the vitamin D receptor (VDR) are present in the nucleus bound to chromatin as a heterodimer with the retinoid X receptors (RXRs) and repress gene expression. Ligand binding leads to transcription activation. The hormonal ligands for these receptors play crucial roles to ensure the proper conduct of very many tissues and exert effects on prostate cancer (PCa) cells. Androgens support PCa proliferation and androgen deprivation alone or with chemotherapy is the standard therapy for PCa. RARγ activation and 3,5,3'-triiodo-L-thyronine (T3) stimulation of TRβ support the growth of PCa cells. Ligand stimulation of VDR drives growth arrest, differentiation, and apoptosis of PCa cells. Often these receptors are explored as separate avenues to find treatments for PCa and other cancers. However, there is accumulating evidence to support receptor interactions and crosstalk of regulatory events whereby a better understanding might lead to new combinatorial treatments.

Genetic and biological drivers of prostate cancer disparities in Black men

Black men with prostate cancer have historically had worse outcomes than white men with prostate cancer. The causes of this disparity in outcomes are multi-factorial, but a potential basis is that prostate cancers in Black men are biologically distinct from prostate cancers in white men. Evidence suggests that genetic and ancestral factors, molecular pathways involving androgen and non-androgen receptor signalling, inflammation, epigenetics, the tumour microenvironment and tumour metabolism are contributing factors to the racial disparities observed. Key genetic and molecular pathways linked to prostate cancer risk and aggressiveness have potential clinical relevance. Describing biological drivers of prostate cancer disparities could inform efforts to improve outcomes for Black men with prostate cancer.

Risk Allele Frequency Analysis and Risk Prediction of Single-Nucleotide Polymorphisms for Prostate Cancer

The incidence of prostate cancer (PCa) varies by ethnicity. This study aimed to provide insights into the genetic cause of PCa, which can result in differences in incidence among individuals of diverse ancestry. We collected data on PCa-associated single-nucleotide polymorphisms (SNPs) from a genome-wide association study catalog. Fisher's exact tests were used to analyze the significance of enrichment or depletion of the effect on the allele at a given SNP. A network analysis was performed based on PCa-related SNPs that showed significant differences among ethnicities. The SNP-based polygenic risk score (PRS) was calculated, and its correlation with PCa incidence was evaluated. European, African, and East Asian populations had different heatmap patterns. Calculated PRS from the allele frequencies of PCa was the highest among Africans, followed by Europeans, and was the lowest among East Asians. PRS was positively correlated with the incidence and mortality of PCa. Network analysis revealed that AR, CDKN1B, and MAD1L1 are genes related to ethnic differences in PCa. The incidence and mortality of PCa showed a strong correlation with PRS according to ethnicity, which may suggest the effect of genetic factors, such as the AR gene, on PCa pathogenesis.

The Role of Aromatase Enzyme in Hormone Related Diseases and Plant-Based Aromatase Inhibitors as Therapeutic Regimens

Medicinal plants have a long history of use as food and remedy in traditional and modern societies, as well as have been used as herbal drugs and sources of novel bioactive compounds. They provide a wide array of chemical compounds, many of which can not be synthesized via current synthesis methods. Natural products may provide aromatase inhibitory activity through various pathways and may act clinically effective for treating pathologies associated with excessive aromatase secretion including breast, ovarian and endometrial cancers, endometriosis, uterine fibroid, benign prostatic hyperplasia (BPH), prostate cancer, infertility, and gynecomastia. Recent studies have shown that natural products with aromatase inhibitory activity, could also be good options against secondary recurrence of breast cancer by exhibiting chemopreventive effects. Therefore, screening for new plant-based aromatase inhibitors may provide novel leads for drug discovery and development, particularly with increased clinical efficacy and decreased side effects.

Racial disparity in prostate cancer in the African American population with actionable ideas and novel immunotherapies

BACKGROUND

African Americans (AAs) in the United States are known to have a higher incidence and mortality for Prostate Cancer (PCa). The drivers of this epidemiological disparity are multifactorial, including socioeconomic factors leading to lifestyle and dietary issues, healthcare access problems, and potentially tumor biology.

RECENT FINDINGS

Although recent evidence suggests once access is equal, AA men have equal outcomes to Caucasian American (CA) men, differences in PCa incidence remain, and there is much to do to reverse disparities in mortality across the USA. A deeper understanding of these issues, both at the clinical and molecular level, can facilitate improved outcomes in the AA population. This review first discusses PCa oncogenesis in the context of its diverse hallmarks before benchmarking key molecular and genomic differences for PCa in AA men that have emerged in the recent literature. Studies have emphasized the importance of tumor microenvironment that contributes to both the unequal cancer burden and differences in clinical outcome between the races. Management of comorbidities like obesity, hypertension, and diabetes will provide an essential means of reducing prostate cancer incidence in AA men. Although requiring further AA specific research, several new treatment strategies such as immune checkpoint inhibitors used in combination PARP inhibitors and other emerging vaccines, including Sipuleucel-T, have demonstrated some proven efficacy.

CONCLUSION

Genomic profiling to integrate clinical and genomic data for diagnosis, prognosis, and treatment will allow physicians to plan a "Precision Medicine" approach to AA men. There is a pressing need for further research for risk stratification, which may allow early identification of AA men with higher risk disease based on their unique clinical, genomic, and immunological profiles, which can then be mapped to appropriate clinical trials. Treatment options are outlined, with a concise description of recent work in AA specific populations, detailing several targeted therapies, including immunotherapy. Also, a summary of current clinical trials involving AA men is presented, and it is important that policies are adopted to ensure that AA men are actively recruited. Although it is encouraging that many of these explore the lifestyle and educational initiatives and therapeutic interventions, there is much still work to be done to reduce incidence and mortality in AA men and equalize current racial disparities.

Population-Based Comparison of Different Risk Stratification Systems Among Prostate Cancer Patients

Background

It is not known which risk stratification system has the best discrimination ability for predicting prostate cancer death.

Methods

We identified patients with non-metastatic primary prostate adenocarcinoma diagnosis between 2004 and 2015 using the Surveillance, Epidemiology, and End Results database. Patients were categorized in different risk groups using the three frequently used risk stratification systems of the National Comprehensive Cancer Network guideline (NCCN-g), American Urological Association guideline (AUA-g), and European Association of Urology guideline (EAU-g), respectively. Associations between risk classification and prostate cancer-specific mortality (PCSM) were determined using Kaplan–Meier analyses and multivariable regression with Cox proportional hazards model. Area under the receiver operating characteristics curve (AUC) analyses were used to test the discrimination ability of the three risk grouping systems.

Results

We analyzed 310,062 patients with a median follow-up of 61 months. A total of 36,368 deaths occurred, including 6,033 prostate cancer deaths. For all the three risk stratification systems, the risk groups were significantly associated with PCSM. The AUC of the model relying on NCCN-g, AUA-g, and EAU-g risk stratification systems for PCSM at specifically 8 years were 0.818, 0.793, and 0.689 in the entire population; 0.819, 0.795, and 0.691 in Whites; 0.802, 0.777, and 0.681 in Blacks; 0.862, 0.818, and 0.714 in Asians; 0.845, 0.806, and 0.728 in Chinese patients. Regardless of the age, marital status, socioeconomic status, and treatment modality, AUC of the model relying on NCCN-g and AUA-g for PCSM was greater than that relying on EAU-g; AUC of the model relying on NCCN-g system was greater than that of the AUA-g system.

Conclusions

The NCCN-g and AUA-g risk stratification systems perform better in discriminating PCSM compared to the EAU-g system. The discrimination ability of the NCCN-g system was better than that of the AUA-g system. It is recommended to use NCCN-g to evaluate risk groups for prostate cancer patients and then provide more appropriate corresponding treatment recommendations.

Estrogen Disrupting Pesticides in Nebraska Groundwater: Trends between Pesticide-contaminated Water and Estrogen-related Cancers in An Ecological Observational Study

Estrogen disrupting pesticides (EDP) are pesticides that modify estrogen activities in estrogen-producing vertebrates. A substantial amount of these pesticides has been detected in human tissues, and they function directly to disrupt estrogen synthesis or effector cells. This study examines EDP’s ecological distribution across Nebraska counties and its association with estrogen-related cancers (ERC). To determine the ecological distribution of selected EDP, county-level choropleth maps were created. Moreover, EDP was tested in separate linear models with different ERC to determine the association between ERC and EDP across Nebraska counties. Exposure data for this county-level study was obtained from the quality assessed agrichemical contaminant Nebraska groundwater database between 1 January 1974 and 31 December 2012. Acetochlor, atrazine, and its metabolites, deethylatrazine (DEA), and de-isopropyl atrazine (DIA) were the most frequently detected EDP in Nebraska groundwater. Moreover, Nebraska county-level potential confounder for ERC such as physically unhealthy days, % adult smoking, % obese adult, % uninsured, and % binge drinking were obtained from County Health Rankings 2010. ERC, which is the outcome variable (breast cancer, uterine cancer, and prostate cancer), were obtained from the Nebraska State profile of the National Cancer Institute. This was expressed as county-level age-standardized incidence cancer rates between 1 January 2013 and 31 December 2017. Data characteristics were determined using percentages, mean, median, 25th and 75th percentile, minimum and maximum values. The relationship between county-level cancer rates and % wells positive for pesticides after adjusting for the county level potential confounders were analyzed in a linear regression model. Water supply wells positive for atrazine and DEA were observed to cluster in the South and South East counties of Nebraska. Furthermore, breast cancer and prostate cancer incidence rates were higher in the southeast of Nebraska with more atrazine and DEA. However, breast cancer and prostate cancer were not significantly associated in a linear regression model with any of the observed EDP. In contrast, uterine cancer was statistically associated with % water supply wells positive for acetochlor (β = 4.01, p = 0.04). While consistent associations were not observed between ERC and EDP from the GIS and the linear regression model, this study’s results can drive future conversation concerning the potential estrogenic effects of acetochlor, atrazine, and its metabolites on the incidence of breast, uterine and prostate cancer in the State of Nebraska.

Endocrinology of the Aging Prostate: Current Concepts

Benign prostate hyperplasia (BPH), one of the most common diseases in older men, adversely affects quality-of-life due to the presence of low urinary tract symptoms (LUTS). Numerous data support the presence of an association between BPH-related LUTS (BPH-LUTS) and metabolic syndrome (MetS). Whether hormonal changes occurring in MetS play a role in the pathogenesis of BPH-LUTS is a debated issue. Therefore, this article aimed to systematically review the impact of hormonal changes that occur during aging on the prostate, including the role of sex hormones, insulin-like growth factor 1, thyroid hormones, and insulin. The possible explanatory mechanisms of the association between BPH-LUTS and MetS are also discussed. In particular, the presence of a male polycystic ovarian syndrome (PCOS)-equivalent may represent a possible hypothesis to support this link. Male PCOS-equivalent has been defined as an endocrine syndrome with a metabolic background, which predisposes to the development of type II diabetes mellitus, cardiovascular diseases, prostate cancer, BPH and prostatitis in old age. Its early identification would help prevent the onset of these long-term complications.

Racial/Ethnic Disparities in Prostate Cancer Incidence, Distant Stage Diagnosis, and Mortality by U.S. Census Region and Age Group, 2012-2015

BACKGROUND

We sought to characterize recent prostate cancer incidence, distant stage diagnosis, and mortality rates by region, race/ethnicity, and age group.

METHODS

In SEER*Stat, we examined age-specific and age-adjusted prostate cancer incidence, distant stage diagnosis, and mortality rates by race/ethnicity, census region, and age group. Incidence and mortality analyses included men diagnosed with (n = 723,269) and dying of (n = 112,116) prostate cancer between 2012 and 2015.

RESULTS

Non-Hispanic black (NHB) and non-Hispanic Asian/Pacific Islander (NHAPI) men had the highest and lowest rates, respectively, for each indicator across regions and age groups. Hispanic men had lower incidence and mortality rates than non-Hispanic white (NHW) men in all regions except the Northeast where they had higher incidence [RR, 1.16; 95% confidence interval (CI), 1.14-1.19] and similar mortality. Hispanics had higher distant stage rates in the Northeast (RR, 1.18; 95% CI, 1.08-1.28) and South (RR, 1.22; 95% CI, 1.15-1.30), but similar rates in other regions. Non-Hispanic American Indian/Alaskan Native (NHAIAN) men had higher distant stage rates than NHWs in the West (RR, 1.38; 95% CI, 1.15-1.65). NHBs and Hispanics had higher distant stage rates than NHWs among those aged 55 to 69 years (RR, 2.91; 95% CI, 2.81-3.02 and 1.24; 95% CI, 1.18-1.31, respectively), despite lower overall incidence for Hispanics in this age group.

CONCLUSIONS

For Hispanic and NHAIAN men, prostate cancer indicators varied by region, while NHB and NHAPI men consistently had the highest and lowest rates, respectively, across regions.

IMPACT

Regional and age group differences in prostate cancer indicators between populations may improve understanding of prostate cancer risk and help inform screening decisions.

Association of finasteride with prostate cancer: A systematic review and meta-analysis

BACKGROUND

The Prostate Cancer Prevention Trial has shown a protective effect of finasteride on prostate cancer, but it also showed that finasteride can increase the risk of high-grade prostate cancer. Several studies have investigated the relationship between finasteride and prostate cancer, but these studies have shown inconsistent results.

ETHICS

The protocol was approved by the institutional review board of each study center. Written informed consent will be obtained from all patients before registration, in accordance with the Declaration of Helsinki.

METHODS

We performed a systematic literature review and meta-analysis to assess the association between finasteride and prostate cancer. Systematic literature searches were conducted using PubMed, EMBASE, Science Direct/Elsevier, MEDLINE, CNKI, and the Cochrane Library up to October 2018 to identify studies that involved the relationship between finasteride and prostate cancer. Meta-analysis was performed using Review Manager and Stata software. Combined ORs were identified with 95% confidence intervals (95% CI) in a random or fixed effects model.

RESULTS

Eight studies were identified, including 54,335 cases of patients that used finasteride and 9197 patients who served as placebo controls. Our results illustrate that there is a significant correlation between finasteride use and prostate cancer with combined ORs of 0.70 [0.51, 0.96]. A significant correlation between finasteride use and high-grade prostate cancer was also observed with combined ORs of 2.10 [1.85, 2.38].

CONCLUSIONS

This study confirms that finasteride significantly reduced the risk of prostate cancer; however, the malignant degree of prostate cancer was increased. Studies with larger sample sizes are needed to better clarify the correlation between finasteride use and prostate cancer.

Racial Differences in Immunological Landscape Modifiers Contributing to Disparity in Prostate Cancer

Prostate cancer affects African Americans disproportionately by exhibiting greater incidence, rapid disease progression, and higher mortality when compared to their Caucasian counterparts. Additionally, standard treatment interventions do not achieve similar outcome in African Americans compared to Caucasian Americans, indicating differences in host factors contributing to racial disparity. African Americans have allelic variants and hyper-expression of genes that often lead to an immunosuppressive tumor microenvironment, possibly contributing to more aggressive tumors and poorer disease and therapeutic outcomes than Caucasians. In this review, we have discussed race-specific differences in external factors impacting internal milieu, which modify immunological topography as well as contribute to disparity in prostate cancer.

Predictive factors of prostate cancer diagnosis with PSA 4.0-10.0 ng/ml in a multi-ethnic Asian population, Malaysia

OBJECTIVES

To identify the associated factors determining prostate cancer detection using transrectal ultrasound (TRUS)-guided prostate biopsy, within a multi-ethnic Malaysian population with prostate specific antigen (PSA) between 4.0 and 10.0 ng/ml.

METHODS

Study subjects included men with initial PSA between 4.0 and 10.0 ng/ml that have undergone 12-core TRUS-guided prostate biopsy between 2009 and 2016. The prostate cancer detection rate was calculated, while potential factors associated with detection were investigated via univariable and multivariable analysis.

RESULTS

A total of 617 men from a multi-ethnic background encompassing Chinese (63.5%), Malay (23.1%) and Indian (13.3%) were studied. The overall cancer detection rate was 14.3% (88/617), which included cancers detected at biopsy 1 (first biopsy), biopsy 2 (second biopsy with previous negative biopsy) and biopsy ≥ 3 (third or more biopsies with prior negative biopsies). Indian men displayed higher detection rate (23.2%) and increased risk of prostate cancer development (OR 1.85, 95% CI 1.03-3.32, p < 0.05), compared to their Malay (9.8%) and Chinese (14.0%) counterparts. Multivariable analysis revealed that ethnicity and PSA density (PSAD) are independent factors associated with overall prostate cancer detection rate. A unit increase of PSAD reflected an increase in PSA after controlling for prostate volume.

CONCLUSION

Prostate cancer detection in Malaysia is comparatively lower. Our study suggests that ethnicity and PSA density should be considered when recommending first or repeat TRUS-guided prostate biopsy for prostate cancer detection in a multi-ethnic Malaysian population.

Estrogens and Their Receptors in Prostate Cancer: Therapeutic Implications

A major challenge in clinical management of prostate cancer (PC) is to limit tumor growth and prevent metastatic spreading. Considerable efforts have been made to discover new compounds for PC therapy and recent years have seen promising progress in this field. Pharmacological approaches have been designed to achieve benefits in PC treatment and avoid the negative side effects resulting from administration of antagonists or agonists or new drugs. Nonetheless, the currently available therapies frequently induce resistance and PC progresses toward castration-resistant forms that can be caused by the androgen receptor reactivation and/or mutations, or derangement of signaling pathways. Preclinical and clinical findings have also shown that other nuclear receptors are frequently altered in PC. In this review, we focus on the role of estradiol/estradiol receptor (ER) axis, which controls PC growth and progression. Selective targeting of ER subtypes (α or β) may be an attractive way to limit the growth and spreading of prostatic cancer cells.

Circulating sex hormones in relation to anthropometric, sociodemographic and behavioural factors in an international dataset of 12,300 men

INTRODUCTION

Sex hormones have been implicated in the etiology of a number of diseases. To better understand disease etiology and the mechanisms of disease-risk factor associations, this analysis aimed to investigate the associations of anthropometric, sociodemographic and behavioural factors with a range of circulating sex hormones and sex hormone-binding globulin.

METHODS

Statistical analyses of individual participant data from 12,330 male controls aged 25-85 years from 25 studies involved in the Endogenous Hormones Nutritional Biomarkers and Prostate Cancer Collaborative Group. Analysis of variance was used to estimate geometric means adjusted for study and relevant covariates.

RESULTS

Older age was associated with higher concentrations of sex hormone-binding globulin and dihydrotestosterone and lower concentrations of dehydroepiandrosterone sulfate, free testosterone, androstenedione, androstanediol glucuronide and free estradiol. Higher body mass index was associated with higher concentrations of free estradiol, androstanediol glucuronide, estradiol and estrone and lower concentrations of dihydrotestosterone, testosterone, sex hormone-binding globulin, free testosterone, androstenedione and dehydroepiandrosterone sulfate. Taller height was associated with lower concentrations of androstenedione, testosterone, free testosterone and sex hormone-binding globulin and higher concentrations of androstanediol glucuronide. Current smoking was associated with higher concentrations of androstenedione, sex hormone-binding globulin and testosterone. Alcohol consumption was associated with higher concentrations of dehydroepiandrosterone sulfate, androstenedione and androstanediol glucuronide. East Asians had lower concentrations of androstanediol glucuronide and African Americans had higher concentrations of estrogens. Education and marital status were modestly associated with a small number of hormones.

CONCLUSION

Circulating sex hormones in men are strongly associated with age and body mass index, and to a lesser extent with smoking status and alcohol consumption.

Pre-treated theaflavin-3,3'-digallate has a higher inhibitory effect on the HCT116 cell line

The pro-apoptotic and inhibitory effects of the aflavin-3,3′-digallate (TFDG), which is the typical pigment in black tea, have been demonstrated in many cancer cell lines. However, TFDG is not stable in general culture conditions. So, to what extent TFDG or which degradation products of TFDG play an antitumor role is still unclear. In this study, we evaluated the effect of different treatments of TFDG on HCT116 cells. Compared with the control, both TFDG and O-TFDG (the TFDG that was pre-incubated in an incubator at 37°C for 3 hbefore adding into 96-well plates) significantly inhibited HCT116 cell growth. However, pre-treated TFDG was far better than TFDG. The IC50 values of TFDG and O-TFDG-3 were 17.26 μM and 8.98 μM, respectively (the cells were treated by O-TFDG for only 3 h, after which the media were replaced by fresh media for another 69 h incubation). Cell-cycle analysis revealed that 20 μM of O-TFDG and O-TFDG-3 caused cell-cycle arrest at G2 phase in HCT116 cells. Western blot analysis also demonstrated that the anti-inflammatory effect of O-TFDG-3 is stronger than that of TFDG by decreasing COX-2 and iNOS. On the other hand, O-TFDG induced HCT116 cells apoptosis mainly by increasing the expression of p53, p21, and cleaved caspase-3. The current study demonstrated that O-TFDG had a higher inhibitory effect on HCT116 cells than TFDG, and sowe may inferfromthis that the degradation products of TFDG play a key role against tumors.

Association between SRD5A2 rs523349 and rs9282858 Polymorphisms and Risk of Benign Prostatic Hyperplasia: A Meta-Analysis

Objective: Previous studies have reported that rs523349 (V89L) and rs9282858 (A49T) polymorphisms in the gene 5α-reductase II (SRD5A2) are associated with the risk of benign prostatic hyperplasia (BPH), but different opinions have emerged. In view of distinct discrepancies among those findings, we performed this meta-analysis to ascertain a more accurate association between SRD5A2 rs523349 and rs9282858 polymorphisms and the risk of BPH. Methods: Studies investigating the association between SRD5A2 rs523349 and rs9282858 polymorphisms and susceptibility to BPH were searched from the databases of PubMed, Embase, Wanfang, and Chinese National Knowledge Infrastructure (CNKI).The strength of correlation was assessed by crude odds ratios (ORs) with their corresponding 95% confidence intervals (95% CIs). Moreover, subgroup analysis was conducted to further ascertain such relationship and investigate sources of heterogeneity. Results:SRD5A2 rs9282858 (A49T) polymorphism showed a significant correlation with increased BPH susceptibility under allele T vs.allele A genetic model (OR = 2.51, 95% CI = 1.29-4.88) in total analysis, and stratification analysis by ethnicity also revealed a similar association in Caucasian group under the same contrast. SRD5A2 rs523349 (V89L) polymorphism showed no significant role in BPH occurrence in total analysis, but its reducing and increasing effects on the disease risk were reflected in Caucasian and other-ethnicity subgroups, respectively, after stratification analysis by ethnicity. Conclusion: In conclusion, SRD5A2 rs9282858 polymorphism may elevate the susceptibility to BPH, while the polymorphism rs523349 may exert different influences on the disease in people of different ethnic lines.

Comprehensive assessment of estrogen receptor beta antibodies in cancer cell line models and tissue reveals critical limitations in reagent specificity

Estrogen Receptor-β (ERβ) has been implicated in many cancers. In prostate and breast cancer its function is controversial, but genetic studies implicate a role in cancer progression. Much of the confusion around ERβ stems from antibodies that are inadequately validated, yet have become standard tools for deciphering its role. Using an ERβ-inducible cell system we assessed commonly utilized ERβ antibodies and show that one of the most commonly used antibodies, NCL-ER-BETA, is non-specific for ERβ. Other antibodies have limited ERβ specificity or are only specific in one experimental modality. ERβ is commonly studied in MCF-7 (breast) and LNCaP (prostate) cancer cell lines, but we found no ERβ expression in either, using validated antibodies and independent mass spectrometry-based approaches. Our findings question conclusions made about ERβ using the NCL-ER-BETA antibody, or LNCaP and MCF-7 cell lines. We describe robust reagents, which detect ERβ across multiple experimental approaches and in clinical samples.

Racial Disparity in Prostate Cancer-Specific Mortality for High-Risk Prostate Cancer: A Population-Based Study

INTRODUCTION

Race may be a significant factor that influences prostate cancer (PCa) survival, with the Asian (AsA) race being associated with better outcomes compared to African American (AA) and Non-Hispanic Whites (NHW). This study evaluates race-dependent variation in PCa-specific mortality (PCSM) associated with radiation dose-escalation exemplified by external beam radiotherapy (EBRT) with a brachytherapy (BT) boost in Gleason score 8-10 PCa.

METHODS

28,956 men diagnosed with clinically localized PCa and Gleason score 8-10 from 2004-2013 who received EBRT, EBRT with a BT boost, or radical prostatectomy (RP) were identified using the Surveillance, Epidemiology, and End Results (SEER) database. PCSM adjusted for age, diagnosis year, T-stage, Gleason scores, and treatment modalities was compared between races using a competing risk model that accounted for other-cause mortality (OCM).

RESULTS

Compared to AsA, AA and NHW are associated with significantly increased PCSM with adjusted hazard ratios (AHR) of 2.295 and 1.989, respectively (p < 0.001 for both). In a subgroup analysis stratified by race, dose-escalation exemplified by EBRT with a BT boost in both AA and AsA failed to demonstrate a significant difference in PCSM compared to EBRT alone (p = 0.530 and 0.990, respectively), while a significant PCSM decrease was seen in NHW (p = 0.006).

CONCLUSIONS

Dose-escalation exemplified by EBRT with a BT boost had no significant effect on PCSM of AsA and AA, while it did decrease PCSM amongst NHW. Further evaluation of race as a factor impacting PCSM in the era of dose-escalation is needed in the prospective setting.

Molecular basis for prostate cancer racial disparities

Prostate cancer (PCa) remains the most common cancer in American men. African-American (AA) men continue to have higher PCa prevalence and mortality rates compared to men in other populations. In addition to socioeconomic factors and lifestyle differences, molecular alterations contribute to this discrepancy. We summarize molecular genetics research results interrelated with the biology of PCa racial disparity. Androgen and androgen receptor (AR) pathways have long been associated with prostate growth. Racial differences have also been found among variants of genes of the enzymes involved in androgen biosynthesis and metabolism. Growth factors and their receptors are a potential cause of the disparity in PCa. Recent molecular and biotechnological approaches in the field of proteomics and genomics will greatly aid the advancement of translational research on racial disparity in PCa, which may help, in finding new prognostic markers and novel therapeutic approaches for the treatment of PCa in AA.

Prostate cancer stem cells: the role of androgen and estrogen receptors

Prostate cancer is one of the most commonly diagnosed cancers in men, and androgen deprivation therapy still represents the primary treatment for prostate cancer patients. This approach, however, frequently fails and patients develop castration-resistant prostate cancer, which is almost untreatable.

Cancer cells are characterized by a hierarchical organization, and stem/progenitor cells are endowed with tumor-initiating activity. Accumulating evidence indicates that prostate cancer stem cells lack the androgen receptor and are, indeed, resistant to androgen deprivation therapy. In contrast, these cells express classical (α and/or β) and novel (GPR30) estrogen receptors, which may represent new putative targets in prostate cancer treatment.

In the present review, we discuss the still-debated mechanisms, both genomic and non-genomic, by which androgen and estradiol receptors (classical and novel) mediate the hormonal control of prostate cell stemness, transformation, and the continued growth of prostate cancer. Recent preclinical and clinical findings obtained using new androgen receptor antagonists, anti-estrogens, or compounds such as enhancers of androgen receptor degradation and peptides inhibiting non-genomic androgen functions are also presented. These new drugs will likely lead to significant advances in prostate cancer therapy.

Long-term Consequences of Finasteride vs Placebo in the Prostate Cancer Prevention Trial

BACKGROUND

Finasteride has been found to reduce the risk of low-grade prostate cancer but to have no impact on overall survival. The long-term adverse and beneficial consequences of finasteride have not been examined.

METHODS

We used a linkage between data from the Prostate Cancer Prevention Trial (PCPT) and Medicare claims. Patients were examined by randomized study arm (finasteride vs placebo for 7 years) for long-term consequences of the intervention, including cardiac, endocrine, and sexual dysfunction, depression, diabetes, and benign prostatic hyperplasia (BPH)-related events. To examine time to events, we used cumulative incidence and Cox regression, adjusting for covariates. All statistical tests were two-sided.

RESULTS

A total of 13 935 of 18 880 participants (73.8%) in the PCPT were linked to Medicare claims, with median Medicare follow-up assessment time of 16 years from trial registration. There were no differences between finasteride and placebo participants with respect to important baseline factors or amount of Medicare follow-up assessment time. Finasteride patients had a 10% higher risk of new claims for depression (hazard ratio [HR] = 1.10, 95% confidence interval [CI] = 1.01 to 1.19, P = .04) and a 6% lower risk of procedures for BPH-related events (primarily lower urinary tract symptoms; HR = 0.94, 95% CI = 0.89 to 1.00, P = .03). No other differences were found in rates of long-term consequences of intervention in the two study arms.

CONCLUSIONS

Finasteride use is associated with reduced need for procedures for relief of BPH-related events and a modest increase in depression. Overall, there is little need to worry about long-term noncancer consequences of finasteride use in those who use it for treatment of symptomatic BPH, hair growth, or prevention of cancer.

Association of androgen metabolism gene polymorphisms with prostate cancer risk and androgen concentrations: Results from the Prostate Cancer Prevention Trial

BACKGROUND

Prostate cancer is highly influenced by androgens and genes. The authors investigated whether genetic polymorphisms along the androgen biosynthesis and metabolism pathways are associated with androgen concentrations or with the risk of prostate cancer or high-grade disease from finasteride treatment.

METHODS

A nested case-control study from the Prostate Cancer Prevention Trial using data from men who had biopsy-proven prostate cancer (cases) and a group of biopsy-negative, frequency-matched controls was conducted to investigate the association of 51 single nucleotide polymorphisms (SNPs) in 12 genes of the androgen pathway with overall (total), low-grade, and high-grade prostate cancer incidence and serum hormone concentrations.

RESULTS

There were significant associations of genetic polymorphisms in steroid 5α-reductase 1 (SRD5A1) (reference SNPs: rs3736316, rs3822430, rs1560149, rs248797, and rs472402) and SRD5A2 (rs2300700) with the risk of high-grade prostate cancer in the placebo arm of the Prostate Cancer Prevention Trial; 2 SNPs were significantly associated with an increased risk (SRD5A1 rs472402 [odds ratio, 1.70; 95% confidence interval, 1.05-2.75; Ptrend = .03] and SRD5A2 rs2300700 [odds ratio, 1.94; 95% confidence interval, 1.19-3.18; Ptrend = .01]). Eleven SNPs in SRD5A1, SRD5A2, cytochrome P450 family 1, subfamily B, polypeptide 1 (CYP1B1), and CYP3A4 were associated with modifying the mean concentrations of serum androgen and sex hormone-binding globulin; and 2 SNPs (SRD5A1 rs824811 and CYP1B1 rs10012; Ptrend < .05) consistently and significantly altered all androgen concentrations. Several SNPs (SRD5A1 rs3822430, SRD5A2 rs2300700, CYP3A43 rs800672, and CYP19 rs700519; Ptrend < .05) were significantly associated with both circulating hormone levels and prostate cancer risk.

CONCLUSIONS

Germline genetic variations of androgen-related pathway genes are associated with serum androgen concentrations and the risk of prostate cancer. Further studies to examine the functional consequence of novel causal variants are warranted. Cancer 2016;122:2332-2340. © 2016 American Cancer Society.

Steroids in house sparrows (Passer domesticus): Effects of POPs and male quality signalling

At high trophic levels, environmental contaminants have been found to affect endocrinological processes. Less attention has been paid to species at lower trophic levels. The house sparrow (Passer domesticus) may be a useful model for investigating effects of POPs in mid-range trophic level species. In male house sparrows, ornamental traits involved in male quality signalling are important for female selection. These traits are governed by endocrinological systems, and POPs may therefore interfere with male quality signalling. The aim of the present study was to use the house sparrow as a mid-range trophic level model species to study the effects of environmental contaminants on endocrinology and male quality signalling. We analysed the levels of selected PCBs, PBDEs and OCPs and investigated the possible effects of these contaminants on circulating levels of steroid hormones (4 progestagens, 4 androgens and 3 estrogens) in male and female adult house sparrows from a population on the island Leka, Norway. Plasma samples were analysed for steroid hormones by GC-MS and liver samples were analysed for environmental contaminants by GC-ECD and GC-MS. In males, we also quantified ornament traits. It was hypothesised that POPs may have endocrine disrupting effects on the local house sparrow population and can thus interfere with the steroid hormone homeostasis. Among female house sparrows, bivariate correlations revealed negative relationships between POPs and estrogens. Among male sparrows, positive relationships between dihydrotestosterone levels and PCBs were observed. In males, positive relationships were also found between steroids and beak length, and between steroids and ornamental traits such as total badge size. This was confirmed by a significant OPLS model between beak length and steroids. Although sparrows are in the mid-range trophic levels, the present study indicates that POPs may affect steroid homeostasis in house sparrows, in particular for females. For males, circulating steroid levels appears to be more associated with biometric parameters related to ornamental traits.

Serum androgens and prostate cancer risk: results from the placebo arm of the Prostate Cancer Prevention Trial

BACKGROUND

Compelling and long-standing data suggest that androgens play an important role in the development of both normal prostate epithelium and prostate cancer. Although testosterone administration can induce prostate cancer (PCA) in laboratory animals, serum-based epidemiologic studies examining androgens in humans have not consistently supported a role for androgens in prostate carcinogenesis. We examined whether pre-diagnostic serum androgens were associated with PCA risk in the placebo arm of the Prostate Cancer Prevention Trial.

METHODS

In this nested case-control study, cases (n = 1,032) were primarily local-stage, biopsy-detected cancers, and controls (n = 1,025) were biopsy-confirmed to be PCA-free. Pre-diagnostic serum androgens (total testosterone, 3α-androstanediol glucuronide, free testosterone), estrogen-to-testosterone ratio, and sex hormone-binding globulin (SHBG) concentrations were measured in pooled (baseline and year 3) blood samples.

RESULTS

We found no significant associations between serum androgens, estrogen-to-testosterone ratios, or SHBG and risk of total, low (Gleason <7) or high-grade (Gleason 7-10) PCA.

CONCLUSION

Much remains to be learned about the role of androgens in prostate carcinogenesis. Further research is needed to evaluate the role of androgens, timing of exposure, genetic modulators of androgen metabolism, or environmental exposures that may affect androgen influence on prostate carcinogenesis.

Assay reproducibility of serum androgen measurements using liquid chromatography-tandem mass spectrometry

BACKGROUND

Valid and precise measures of androgen concentrations are needed for etiologic studies of hormonally-related cancers. We developed a high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with two sample preparations to measure 11 androgens, including adrenal and gonadal androgenic precursors and their 5α-reduced metabolites.

METHODS

Androgen levels were measured in serum from 20 healthy volunteers (5 men, 10 premenopausal women, 5 postmenopausal women). Two blinded, randomized aliquots per individual were assayed in each of three batches. A fourth batch of samples was measured at an external laboratory using comparable methodology to measure 9 of the 11 androgens. Coefficients of variation (CV) and intraclass correlation coefficients (ICC) were calculated from the individual components of variance. Comparability of 9 androgens across laboratories was assessed using Spearman ranked correlations, Deming regression and bias plots.

RESULTS

The laboratory CVs were <5% and ICCs were uniformly high (>95%) for all androgens measured across sex/menopausal status groups. Spearman ranked correlations for 9 hormones measured in the comparison laboratory were high (>0.85), suggesting good agreement.

CONCLUSION

Our high-performance LC-MS/MS assays of 11 androgens, including adrenal and gonadal androgenic precursors and their 5α-reduced metabolites demonstrated excellent laboratory reproducibility, and good comparability with an established method that measured 9 of the 11 hormones tested. The serum androgen metabolite assays are suitable for use in epidemiologic research.

SRD5A2 gene polymorphisms and the risk of benign prostatic hyperplasia but not prostate cancer

BACKGROUND

Testosterone, a primary androgen in males, is converted into its most active form, dihydrotestosterone (DHT), by 5α-reductase type 2 (encoded by the SRD5A2 gene) in the prostate. DHT is necessary for prostatic growth and has five times higher binding affinity than testosterone for androgen receptors. We hypothesized that polymorphic variations in the SRD5A2 gene may affect the risk of benign prostatic hyperplasia and prostate cancer.

MATERIALS AND METHODS

We analyzed SRD5A2 gene polymorphisms in 217 BPH patients, 192 PCa cases, and 171 controls. Genotyping was undertaken using direct DNA sequencing. Genotype data were compared between cases and controls using a Chi square statistical tool.

RESULTS

We found that the A49T locus was monomorphic with 'AA' genotype in all subjects. At V89L locus, the presence of 'VV' showed a marginally significant correlation with increased BPH risk (p=0.047). At the (TA)n locus, longer TA repeats were found to be protective against BPH (p=0.003). However, neither of these polymoprhisms correlated with the risk of PCa.

CONCLUSIONS

We conclude that A49T is monomorphic in the study population, VV marginally correlates with BPH risk, and longer (TA)n repeats are protective against BPH. None of these polymorphisms affect the risk of PCa.

Differences in the aggressiveness of prostate cancer among Korean, Caucasian, and African American men: A retrospective cohort study of radical prostatectomy

PURPOSE

We aimed to compare the pathologic aggressiveness of clinically localized prostate cancer (PCa) treated by radical prostatectomy in Korean and Western (Caucasian and African American [AA]) men by analyzing data from representative hospitals in the capitals of Korea (Seoul) and the United States (Washington, DC).

METHODS

We performed a retrospective cohort study of 1,939 patients who underwent radical prostatectomy for clinically localized PCa in the Asan Medical Center and Washington Hospital Center. After adjusting for confounding clinical variables, we used multivariate logistic regression analysis to assess differences in the aggressiveness of PCa.

RESULTS

We analyzed 1,152 Korean, 473 Caucasian, and 314 AA patients. There were significant differences between Korean and Western patients in terms of age at surgery, preoperative levels of prostate-specific antigen, and clinical stage (P<0.001). Overall, high-grade PCa (Gleason score≥8) was more common in Korean (19.4%) than in AA (6.1%) or Caucasian (5.5%) patients (P<0.001). The incidence of advanced-stage PCa (pT3 or higher) was higher in Korean (34.8%) than in AA (18.2%) or Caucasian (13.3%) patients (P<0.001). After adjusting for age, prostate-specific antigen, prostate volume, and clinical stage, multivariate logistic regression analysis showed that Korean men had a high risk of high-grade PCa (Korean vs. Caucasian, odds ratio [OR] = 3.48, P<0.001; Korean vs. AA, OR=3.14, P<0.001) or advanced-stage PCa (Korean vs. Caucasian, OR=2.40, P<0.001; Korean vs. AA, OR = 1.59, P = 0.009) than Western men.

CONCLUSIONS

There are differences in PCa aggressiveness between Korean and Western men. The incidence of high-grade or advanced-stage PCa is higher in Korean men.

Polymorphism of the SRD5A2 gene and the risk of prostate cancer

Androgens are actively involved in the development of the prostate gland and appear to be essential for prostate carcinogenesis. The product of the SRD5A2 gene, membrane‑bound steroid 5‑α‑reductase, type II enzyme, is key in testosterone metabolism. The present study explored the association between the SRD5A2 V89L gene polymorphism and the risk of developing prostate cancer. The study cohort consisted of 456 male Slovak patients, including 260 cases with histologically confirmed prostate cancer and 196 age‑matched controls without any clinically suspected infections of the prostate. Polymerase chain reaction-restriction fragment length polymorphism analysis was used to detect the SRD5A2 polymorphism on codon 89. Odds ratios (ORs) with corresponding 95% confidence intervals (95% CIs) for different allele variants were calculated in order to determine the association between the SRD5A2 V89L gene polymorphism and prostate cancer. The distribution of V89L variants in the control group was consistent with the Hardy‑Weinberg equilibrium (χ2 test, P=0.266) with a significant deviation in the case group (χ2 test, P=0.04). However, no association between the SRD5A2 polymorphism and an increased risk of developing prostate cancer was identified. When the wild type VV variant was used as a reference, the ORs for different allele variants ranged from 1.11 (95% CI 0.66‑1.87, P=0.70) for the LL genotype to 0.99 (95% CI 0.68‑1.46, P=0.99) for the LL + VL genotypes. No particular allele variant was identified to exhibit an increased capacity to promote the development of highly aggressive prostate cancer (Gleason ≥7) or induce carcinogenesis at an earlier onset (<65 years of age). It was confirmed that in the population studied, the SRD5A2 V89L polymorphism was not associated with the risk of prostate cancer and SRD5A2 was not shown to be a key gene involved in prostate cancer development. Published data indicate that a combination of multiple genetic changes are required for prostate cancer development, rather than a single gene change. Therefore, it was hypothesized that high-throughput genotyping may be more effective than single nucleotide polymorphism detection.

Estrogen receptor beta in prostate cancer: friend or foe?

Prostate cancer is the commonest, non-cutaneous cancer in men. At present, there is no cure for the advanced, castration-resistant form of the disease. Estrogen has been shown to be important in prostate carcinogenesis, with evidence resulting from epidemiological, cancer cell line, human tissue and animal studies. The prostate expresses both estrogen receptor alpha (ERA) and estrogen receptor beta (ERB). Most evidence suggests that ERA mediates the harmful effects of estrogen in the prostate, whereas ERB is tumour suppressive, but trials of ERB-selective agents have not translated into improved clinical outcomes. The role of ERB in the prostate remains unclear and there is increasing evidence that isoforms of ERB may be oncogenic. Detailed study of ERB and ERB isoforms in the prostate is required to establish their cell-specific roles, in order to determine if therapies can be directed towards ERB-dependent pathways. In this review, we summarise evidence on the role of ERB in prostate cancer and highlight areas for future research.

Prostate cancer risk profiles of Asian-American men: disentangling the effects of immigration status and race/ethnicity

PURPOSE

Asian-American men with prostate cancer have been reported to present with higher grade and later stage disease than white American men. However, Asian-American men comprise a heterogeneous population with distinct health outcomes. We compared prostate cancer risk profiles among the diverse racial and ethnic groups in California.

MATERIALS AND METHODS

We used data from the California Cancer Registry on 90,845 nonHispanic white, nonHispanic black and Asian-American men diagnosed with prostate cancer between 2004 and 2010. Patients were categorized into low, intermediate and high risk groups based on clinical stage, Gleason score and prostate specific antigen at diagnosis. Using polytomous logistic regression we estimated adjusted ORs for the association of race/ethnicity and nativity with risk group.

RESULTS

In addition to the nonHispanic black population, 6 Asian-American groups (United States born Chinese, foreign born Chinese, United States born Japanese, foreign born Japanese, foreign born Filipino and foreign born Vietnamese) were more likely to have an unfavorable risk profile compared to nonHispanic white men. The OR for high vs intermediate risk disease ranged from 1.23 (95% CI 1.02-1.49) for United States born Japanese men to 1.45 (95% CI 1.31-1.60) for foreign born Filipino men. These associations appeared to be driven by higher grade and prostate specific antigen rather than by advanced clinical stage at diagnosis.

CONCLUSIONS

In this large, ethnically diverse, population based cohort Asian-American men were more likely to have an unfavorable risk profile at diagnosis. This association varied by racial/ethnic group and nativity, and was not attributable to later stage at diagnosis. This suggests that Asian men may have biological differences that predispose to more severe disease.

The effect of testosterone replacement therapy on prostate cancer: a systematic review and meta-analysis

BACKGROUND

Testosterone replacement therapy (TRT) is a widely accepted form of treatment worldwide for aging men with late-onset hypogonadism syndrome. Urologists have been concerned about the possibility of TRT causing prostate cancer. The aim of this study was to assess the relationship between TRT and prostate cancer.

METHODS

A literature review was performed to identify all published, randomized controlled trials (RCTs) of testosterone treatment for hypogonadism. The search included the MEDLINE, Embase and the Cochrane Controlled Trials Register databases. Fixed-effect model was chosen for homogeneous studies; otherwise, a random-effect model was used. Inconsistency was quantified by using the I2 statistic, which tests the proportion of heterogeneity across studies.

RESULTS

Results of 22 RCTs involving a total of 2351 patients were analyzed. Eleven RCTs were short-term (<12 months) and 11 were long-term (12-36 months) comparisons of TRT with a placebo; TRT was administered transdermally, orally or by injection. Respective odds ratio (OR) and 95% confidence interval (CI) values for injection, transdermal administration and oral administration of short-term TRT were as follows: prostate cancer: 0.39 (0.06-2.45), 1.10 (0.26-4.65) and no oral; biopsy: 5.28 (0.24-113.87), 2.11 (0.32-13.73) and no oral; and prostate nodule: 1.01 (0.13-7.60), no injection and oral. Respective OR and 95% CI values for injection, transdermal administration and oral administration of long-term TRT were as follows: prostate cancer: 2.09 (0.18-24.73), 3.06 (0.12-76.70) and 0.19 (0.01-4.03); biopsy: 2.09 (0.18-24.73), 3.65 (0.88-15.20) and 0.97 (0.13-7.03); and prostate nodule: 3.13 (0.12-80.68), 1.00 (0.06-16.41) and 0.97 (0.13-7.03). Though for some routes of administration and some end points, the OR associated with testosterone administration were >1 indicating increased risk, none of these reached or even approached statistical significance (all P>0.10), which was consistent with the results of subgroup analyses and sensitivity analysis. Besides, sensitivity analysis indicated that short-term TRT was more likely to increase PSA levels than treatment with placebo (P<0.00001).

CONCLUSIONS

This meta-analysis shows that regardless of the administration method, TRT is the short-term safety and does not promote prostate cancer development or progression but long-term data are warranted with justifiable end points.

UGT2B17 Polymorphism and Risk of Prostate Cancer: A Meta-Analysis

Objective. Recent studies on the association between uridine diphosphosglucuronosyltransferases (UGTs) 2B17 polymorphism and risk of prostate cancer (PCa) showed inconclusive results. To clarify this possible association, we conducted a meta-analysis of published studies. Methods. We searched the published literature from PubMed, Embase, Google Scholar, and China National Knowledge Infrastructure (CNKI). According to our inclusion criteria, studies that observed the association between UGT2B17 polymorphism and PCa risk were included. The principal outcome measure was the adjusted odds ratio (OR) with 95% confidence interval (CI) for the risk of PCa associated with UGT2B17 polymorphism. Results. A total of 6 studies with 7,029 subjects (3,839 cases and 3,190 controls) were eligible for inclusion in the meta-analysis. Overall, there was a significant association between UGT2B17 polymorphism and increased risk of prostate cancer (OR = 1.74, 95% CI 1.14-2.64, P < 0.001). Similar results were found in the subgroup analyses by ethnicity and types of controls. Conclusion. This meta-analysis demonstrates that UGT2B17 polymorphism is associated with prostate cancer susceptibility, and it contributes to the increased risk of prostate cancer.

Phase two steroid metabolism and its roles in breast and prostate cancer patients

Breast and prostate cancer are diseases in which steroids and steroid metabolism could markedly influence clinical outcomes for patients. In both malignancies the modification of ketone and hydroxyl groups attached to the steroid backbone (phase one metabolism) has been examined in detail but the conjugation reactions (phase two metabolism) have not been extensively studied. Therefore, in this review we aim to summarize phase two metabolism in breast and prostate cancers from a number of perspectives, including the impact of variation in serum levels of conjugated steroids, tissue, and pathology specific expression of phase two enzymes, and consequences of genetic variations of these conjugation enzymes. In addition to this biological perspective, we will also address current pharmacological efforts to manipulate phase two metabolism as a potential therapy for hormone dependent cancers, including clinical trials of STS inhibitors and preclinical STS inhibitor development. While this review is not intended to cover any one particular area in great technical depth, it is intended as an introduction to and/or update on the importance of variance in phase two metabolic pathways in breast and prostate cancers.

Steroid 5-alpha-reductase type 2 (SRD5A2) V89L and A49T polymorphisms and sporadic prostate cancer risk: a meta-analysis

Steroid 5-α-reductase type 2 (SRD5A2) V89L and A49T polymorphisms are thought to play a crucial role in the androgen synthesis and metabolic pathway, but their associations with prostate cancer risk remain controversial. To provide a more precise estimation of the associations between V89L and A49T polymorphisms and prostate cancer risk, we performed a meta-analysis using all published case-control studies of prostate cancer since January 1995. We used odds ratio (OR) and its 95% confidence interval (CI) to assess the strength of the association under various genetic models in both overall and stratified analyses. We also calculated the false-positive report probability, the power of the current study, and the observed P value for significant findings. This analysis included 45 eligible studies of a total of 15,562 cases and 15,385 controls, in which no significant associations were found for the V89L polymorphisms under all genetic models. However, small excess prostate cancer risk was associated with the 49T allele in mixed populations compared with the 49A allele (OR = 1.24, 95% CI = 1.02-1.50), and similar results were observed in Caucasians (OR = 1.24, 95% CI = 1.01-1.53). The sensitivity analysis further strengthened the validity of these findings without publication bias. Although there was no overall association between V89L and prostate cancer risk, A49T might play a role in the etiology of prostate cancer among Caucasians. Additional large and well-designed studies are warranted to validate these findings.

Sex dependent influence of a functional polymorphism in steroid 5-α-reductase type 2 (SRD5A2) on post-traumatic stress symptoms

A non-synonymous, single nucleotide polymorphism (SNP) in the gene coding for steroid 5-α-reductase type 2 (SRD5A2) is associated with reduced conversion of testosterone to dihydrotestosterone (DHT). Because SRD5A2 participates in the regulation of testosterone and cortisol metabolism, hormones shown to be dysregulated in patients with PTSD, we examined whether the V89L variant (rs523349) influences risk for post-traumatic stress disorder (PTSD). Study participants (N = 1,443) were traumatized African-American patients of low socioeconomic status with high rates of lifetime trauma exposure recruited from the primary care clinics of a large, urban hospital. PTSD symptoms were measured with the post-traumatic stress symptom scale (PSS). Subjects were genotyped for the V89L variant (rs523349) of SRD5A2. We initially found a significant sex-dependent effect of genotype in male but not female subjects on symptoms. Associations with PTSD symptoms were confirmed using a separate internal replication sample with identical methods of data analysis, followed by pooled analysis of the combined samples (N = 1,443, sex × genotype interaction P < 0.002; males: n = 536, P < 0.001). These data support the hypothesis that functional variation within SRD5A2 influences, in a sex-specific way, the severity of post-traumatic stress symptoms and risk for diagnosis of PTSD.

Semen quality of fertile Japanese men: a cross-sectional population-based study of 792 men

OBJECTIVES

To establish a base line for future studies on temporal trends, to describe potential geographical differences in semen quality and reference values for studies of men from the general population.

DESIGN

Cross-sectional study of fertile men from four areas in Japan. Inclusion criteria were: age 20-45 years at the time of invitation, and both the man and his mother had to be born in Japan. Additionally, the current pregnancy of the female partner had to be achieved by normal sexual relations without any fertility treatment.

SETTING

Four Japanese study centres at urban areas located in Sapporo, Osaka, Kanazawa and Fukuoka.

PARTICIPANTS

792 men, median age 31.4 years, included from 1999 to 2002.

OUTCOME MEASURES

Semen volume, sperm concentration, total sperm count, sperm motility and sperm morphology.

RESULTS

Semen volumes, percentages of motile spermatozoa and morphologically normal spermatozoa differed slightly between the four groups, whereas no differences in sperm concentrations or total sperm counts were found. In total, 1.2% of men had a sperm concentration below 5 million/ml, 2.1% below 10 million/ml, 3.5% below 15 million/ml and 16.3% below 40 million/ml. For morphology, 14.7% had less than 5% normal spermatozoa. Reproductive hormone levels varied significantly, however, only little from a biological point of view.

CONCLUSIONS

This is the first cross-sectional study on semen quality covering fertile men from the major regions of Japan. It showed that semen quality of fertile Japanese men is comparable to that of the best in European regions. The results may serve as reference values for studies of men from the general population.

Do evolutionary life-history trade-offs influence prostate cancer risk? a review of population variation in testosterone levels and prostate cancer disparities

An accumulation of evidence suggests that increased exposure to androgens is associated with prostate cancer risk. The unrestricted energy budget that is typical of Western diets represents a novel departure from the conditions in which men's steroid physiology evolved and is capable of supporting distinctly elevated testosterone levels. Although nutritional constraints likely underlie divergent patterns of testosterone secretion between Westernized and non-Western men, considerable variability exists in men's testosterone levels and prostate cancer rates within Westernized populations. Here, I use evolutionary life history theory as a framework to examine prostate cancer risk. Life history theory posits trade-offs between investment in early reproduction and long-term survival. One corollary of life history theory is the 'challenge hypothesis', which predicts that males augment testosterone levels in response to intrasexual competition occurring within reproductive contexts. Understanding men's evolved steroid physiology may contribute toward understanding susceptibility to prostate cancer. Among well-nourished populations of Westerners, men's testosterone levels already represent an outlier of cross-cultural variation. I hypothesize that Westernized men in aggressive social environments, characterized by intense male-male competition, will further augment testosterone production aggravating prostate cancer risk.

Testosterone responses to intensive interval versus steady-state endurance exercise

Free testosterone (FT) hormonal responses were compared between high-intensity interval exercise (IE) and steadystate endurance exercise (SSE) in endurance trained males (no.=15). IE session was repeated periods of 90-sec treadmill running at 100-110% maximal oxygen uptake (VO2max) and 90-sec active recovery at 40% VO2max for 42-47 min. The SSE session consisted of a continuous 45-min run at 60-65% VO2max. Total work output was equal for each exercise session. A 45-min supine rest control session (CON) was also performed. All three sessions were on separate days. Pre-session (PRE), immediate post-session (POST), and 12-h post-session (12POST) blood samples were collected and used to determine FT, SHBG, LH, 3- α-androstanediol glucuronide (3-α Diol G) and cortisol. Analysis of variance compared IE and SSE biomarker responses to the reference CON session. IE and SSE each caused an increase (p<0.01) in FT, but IE more so than SSE (p<0.05). The 5α-reductase marker 3-α Diol G response at 12POST IE was elevated while FT was reduced (p<0.05); no such change occurred following SSE. These findings suggest IE might produce a more pronounced turnover of FT by androgen sensitive tissue than the SSE form of exercise.

Racial/ethnic differences in sex hormone levels among postmenopausal women in the diabetes prevention program

CONTEXT

Sex hormones may differ by race/ethnicity in postmenopausal women. Whether racial/ethnic differences also exist among those who are overweight and glucose intolerant is not clear.

OBJECTIVES

The objective of the study was to compare sex hormones by race/ethnicity [non-Hispanic white (NHW), Hispanic, African-American (AA)] in overweight, glucose-intolerant, postmenopausal women.

DESIGN

This was a secondary analysis of a randomized controlled trial.

PARTICIPANTS

Participants included postmenopausal glucose-intolerant women participating in the Diabetes Prevention Program.

INTERVENTIONS

Interventions included intensive lifestyle modification (consisting of diet and physical activity) or metformin 850 mg twice a day vs. placebo.

MAIN OUTCOME MEASURES

Baseline levels and 1-yr intervention-related changes in SHBG, total and bioavailable estradiol (E2), total and bioavailable testosterone, and dehydroepiandrosterone were measured.

RESULTS

At baseline, among women not using estrogen (n = 370), NHW had higher total and bioavailable E2 and testosterone levels than Hispanics independent of age, type of menopause, waist circumference, alcohol intake, and current smoking. NHW also had higher levels of bioavailable E2 and lower levels of SHBG than AA. At baseline, among estrogen users (n = 310), NHW had higher total and bioavailable E2 than Hispanics and higher levels of SHBG than AA after adjustment. At 1 yr, among women not using estrogen, NHW had larger declines in total E2 and bioavailable E2 levels than AA after adjustment for the above covariates, changes in waist circumference, and randomization arm. At 1 yr, among estrogen users, sex hormone changes did not differ by race/ethnicity.

CONCLUSIONS

Among postmenopausal women, there were significant race/ethnicity differences in baseline sex hormones and changes in sex hormones.

The effects of diet on circulating sex hormone levels in men

There is considerable epidemiological evidence that a Western-style diet may increase the risk of certain hormone-dependent conditions in men via its effects on hormone metabolism. Experimental evidence also suggests that dietary factors may exert subtle effects on hormone metabolism. Here we review the clinical and epidemiological evidence that diet is associated with circulating sex hormone levels in men. In comparison with factors such as age and BMI, nutrients do not appear to be strong determinants of sex hormone levels. Dietary intervention studies have not shown that a change in dietary fat and/or dietary fibre intake is associated with changes in circulating sex hormone concentrations over the short term. The data on the effects of dietary phyto-oestrogens on sex hormone levels in men are too limited for conclusions to be drawn. Observational studies between men from different dietary groups have shown that a vegan diet is associated with small but significant increases in sex-hormone-binding globulin and testosterone concentrations in comparison with meat-eaters. However, these studies have not demonstrated that variations in dietary composition have any long-term important effects on circulating bioavailable sex hormone levels in men. This lack of effect may be partly explained by the body's negative feedback mechanism, which balances out small changes in androgen metabolism in order to maintain a constant level of circulating bioavailable androgens. It appears, therefore, that future studies should look for dietary effects on the feedback mechanism itself, or on the metabolism of androgens within the target tissues.

Early detection of high-grade prostate cancer using digital rectal examination (DRE) in men with a prostate-specific antigen level of <2.5 ng/mL and the risk of death

Study Type--Prognosis (inception cohort) Level of Evidence 2a. What's known on the subject? and What does the study add? There is little data on the utility of digital rectal examination (DRE) as a diagnostic tool in the era of prostate-specific antigen (PSA) testing. Using a population-based database, we found that detection of prostate cancer while still localized among men with high-grade PSA-occult disease may result in survival benefit.

OBJECTIVE

• To determine whether detection of high-grade prostate cancer while still clinically localised on digital rectal examination (DRE) can improve survival in men with a normal prostate-specific antigen (PSA) level.

PATIENTS AND METHODS

• From the Surveillance, Epidemiology and End Results database, 166,104 men with prostate cancer diagnosed between 2004 and 2007 were identified. • Logistic regression was used to identify factors associated with the occurrence of palpable, PSA-occult (PSA level of <2.5 ng/mL), Gleason score 8-10 prostate cancer. • Fine and Gray's and Cox multivariable regressions were used to analyse whether demographic, treatment, and clinicopathological factors were associated with the risk of prostate cancer-specific mortality (PCSM) and all-cause mortality (ACM), respectively.

RESULTS

• Both increasing age (adjusted odds ratio [aOR] 1.02, 95% confidence interval (CI) 1.01-1.03; P < 0.001) and White race (aOR 1.26, 95% CI 1.03-1.54; P = 0.027) were associated with palpable, Gleason 8-10 prostate cancer. Of 166,104 men, 685 (0.4%) had this subset of prostate cancer. • Significant factors associated with risk of PCSM included PSA level (adjusted hazard ratio [aHR] 0.71, 95% CI 0.51-0.99; P = 0.04), higher Gleason score (aHR 2.20, 95% CI 1.25-3.87; P = 0.006), and T3-T4 vs T2 disease (aHR 3.11, 95% CI 1.79-5.41; P < 0.001). • Significant factors associated with risk of ACM included age (aHR 1.03, 95% CI 1.01-1.06; P = 0.006), higher Gleason score (aHR 2.05, 95% CI 1.36-3.09; P < 0.001), and T3-T4 vs T2 disease (aHR 2.11, 95% CI 1.38-3.25, P < 0.001)

CONCLUSIONS

• Clinically localised disease on DRE among men with PSA-occult high-grade prostate cancer was associated with improved PCSM and ACM, suggesting that DRE in this cohort (older age and White race) may have the potential to improve survival.