Racial/ethnic variations in male testosterone levels: a probable contributor to group differences in health

Advances in the understanding of androgen receptor structure and function and in the development of next-generation AR-targeted therapeutics

Androgen receptor (AR) and its ligand androgens are important for development and physiology of various tissues. AR and its ligands also play critical role in the development of various diseases, making it a valuable therapeutic target. AR ligands, both agonists and antagonists, are being widely used to treat pathological conditions, including prostate cancer and hypogonadism. Despite AR being studied widely over the last five decades, the last decade has seen striking advances in the knowledge on AR and discoveries that have the potential to translate to the clinic. This review provides an overview of the advances in AR biology, AR molecular mechanisms of action, and next generation molecules that are currently in development. Several of the areas described in the review are just unraveling and the next decade will bring more clarity on these developments that will put AR at the forefront of both basic biology and drug development.

CEO masculine behavior and earnings management: does ethnicity matter?

Purpose

This study aims to investigate the relationship between the Chief Executive Officers (CEOs’) masculinity, CEO characteristics (accounting background, turnover and ethnicity/race) and earnings management (EM) in Malaysia. It also examined the moderating effect of the CEOs’ ethnicity/race (Bumiputera and non-Bumiputera) on the relationship between CEO masculinity and EM.

Design/methodology/approach

The analyses were based on a panel data set of 260 corporates listed on the Bursa Malaysia from 2009 to 2019. Python/code was used to calculate the facial width-to-height ratio (fWHR), while testosterone (TESTN) was calculated based on CEO age and fWHR. To estimate the results, panel data analysis with a fixed effect model was used.

Findings

The result shows that fWHR and TESTN have a significant positive effect on EM. CEO race has a significant impact on EM, implying that non-Bumiputera CEOs are more likely to be associated with EM. There was no statistically significant evidence that race moderates the relationship between CEO masculinity and EM.

Research limitations/implications

The research contributes to the growing evidence in the field of neuroscience that it is possible to infer aspects of an individual’s behavior based on their facial structure and their TESTN levels. The findings provide new evidence supporting Malaysian Government policies in reducing masculinity on boards of directors and senior executive positions, which will positively affect the integrity of financial reports.

Originality/value

To the best of the authors’ knowledge, it is the first research to explain whether the ethnicity/race of CEOs is related to EM and whether it has a significant moderate effect on the relationship between masculinity and EM.

The Insignificant Correlation between Androgen Deprivation Therapy and Incidence of Dementia Using an Extension Survival Cox Hazard Model and Propensity-Score Matching Analysis in a Retrospective, Population-Based Prostate Cancer Registry

This study aims to evaluate the effect of androgen-deprivation therapy (ADT) on the incidence of dementia, after considering the time-dependent survival in patients with prostate cancer (PC) using a Korean population-based cancer registry database. After excluding patients with cerebrovascular disease and dementia before or within the 3-month-ADT and those with surgical castration, 9880 (19.3%) patients were matched into ADT and non-ADT groups using propensity-score matching (PSM) among 51,206 patients registered between 2006 and 2013. To define the significant relationship between ADT duration and the incidence of dementia, the extension Cox proportional hazard model was used with p-values < 0.05 regarded as statistically significant. The mean age and survival time were 67.3 years and 4.33 (standard deviation [SD] 2.16) years, respectively. A total of 2945 (9.3%) patients developed dementia during the study period, including Parkinson’s (11.0%), Alzheimer’s (42.6%), vascular (18.2%), and other types of dementia (28.2%). Despite PSM, the PC-treatment subtypes, survival rate, and incidence of dementia significantly differed between the ADT and non-ADT groups (p < 0.05), whereas the rate of each dementia subtype did not significantly differ (p = 0.069). A multivariate analysis for dementia incidence showed no significance of ADT type or use duration among patients with PC (p > 0.05), whereas old age, obesity, regional SEER stage, a history of cerebrovascular disease, and a high Charlson Comorbidity Index were significant factors for dementia (p < 0.05). Insignificant correlation was observed between ADT and the incidence of dementia based on the extension survival model with PSM among patients with PC.

Overall survival of black and white men with metastatic castration-resistant prostate cancer (mCRPC): a 20-year retrospective analysis in the largest healthcare trust in England

BACKGROUND

Prostate cancer in black men is associated with poorer outcomes than their white counterparts. However, most studies reporting this disparity were conducted in localized prostate cancer and primarily in the United States.

METHODS

Data regarding prostate cancer incidence and mortality for East London between 2008 and 2010 were obtained from the UK National Disease Registration Service. We further evaluated survival outcomes of 425 cases of mCRPC in St Bartholomew's Hospital, East London, between 1997 and 2016, and analyzed whether ethnicity impacted on responses to different treatment types.

RESULTS

The incidence of prostate cancer in black men was higher than white men in East London. Prostate cancer-specific mortality was proportional to incidence based on ethnic groups. In the detailed analysis of 425 patients, 103 patients (24%) were black (B), and the remainder white (W). Baseline characteristics were comparable in both groups, although black patients had a lower baseline hemoglobin (p < 0.001). Median overall survival for the total cohort was 25.5 months (B) vs 21.8 months (W) (hazard ratio (HR) = 0.81, p = 0.08). There was prolonged survival in the black population in those who only received hormone-based treatment throughout their treatment course; 39.7 months (B) vs 17.1 months (W) (HR = 0.54, p = 0.019).

CONCLUSION

Black men may do better than white men with mCRPC, in the context of equal access to healthcare. The study also suggests a greater margin of benefit of hormone-based therapy in the black subpopulation.

Water-pipe smoking and serum testosterone levels in adult males in Qatar

INTRODUCTION

Water-pipe (WP) smoking is the most common method of tobacco consumption in the Middle-East and is rapidly spreading on a global scale. Although, water-pipe smoking is linked to various diseases, such as emphysema and various types of cancers, its effect on testosterone levels has yet to be investigated. This study explores the effect of water-pipe smoking on serum testosterone levels in males in Qatar.

METHODS

In this cross-sectional sample within a cohort study, we retrieved data for a total of 1000 male volunteers from the Qatar BioBank (QBB) project. A self-reported questionnaire was used to determine the water-pipe smoking status of participants. Moreover, participants were stratified based on the frequency of smoking. Total testosterone and sex hormone binding globulin (SHBG) were measured clinically, whereas free testosterone and bioavailable testosterone were calculated using Vermeulen’s equation. Hormone values of 541 males (277 water-pipe smokers and 264 non-smokers) were compared using multiple regression analysis based on water-pipe smoking status after adjusting for confounding factors.

RESULTS

No statistically significant difference was observed between WP smokers and non-water-pipe smokers in the likelihood of having lower or higher total testosterone, after adjustment for confounding factors. Similar results were found in free testosterone, bioavailable testosterone, and sex hormone binding globulin (all p>0.05). When compared with the reference group, both light and heavy water-pipe smokers had a similar likelihood of circulating low total testosterone levels (OR=0.83, 95% CI: 0.46–1.49; and OR=0.80, 95% CI: 0.43–1.49; respectively).

CONCLUSIONS

Our results reveal, for the first time, that there is no significant change in total testosterone, free testosterone, bioavailable testosterone and sex hormone binding globulin in waterpipe smokers compared to non-water-pipe smokers. Therefore, we believe that further studies are needed to confirm the effect of water-pipe smoking on testosterone in different populations.

The effect of ethnicity on semen analysis and hormones in the infertile patient

INTRODUCTION

We aimed to study the association of ethnicity on semen parameters and hormones in patients presenting with infertility.

METHODS

Data from men presenting for infertility assessment were prospectively collected and retrospectively reviewed. Demographic and clinical history was self-reported. Semen analysis included volume, count, motility, morphology, and vitality. The 2010 World Health Organization cutoffs were used. Baseline total testosterone and follicle-stimulating hormone (FSH) levels were recorded. Ethnicity data was classified as Caucasian, African Canadian, Asian, Indo-Canadian, Native Canadian, Hispanic, and Middle Eastern. All patients with complete data were included and statistical analysis was performed.

RESULTS

A total of 9079 patients were reviewed, of which 3956 patients had complete data. Of these, 839 (21.2%) were azoospermic. After adjusting for age, African Canadians (odds ratio [OR] 1.70; 95% confidence interval [CI] 1.28-2.25) and Asians (1.34; 95% CI 1.11-1.62) were more likely to be azoospermic compared to Caucasians. Similarly, African Canadians (OR 1.75; 95% CI 1.33-2.29) were more likely to be oligospermic and Asians (OR 0.82; 95% CI 0.70-0.97) less likely to be oligospermic. Low volume was found in African Canadian (OR 1.42; 95% CI 1.05-1.91), Asians (OR 1.23; 95% CI 1.01-1.51), and Indo-Canadians (OR 1.47; 95% CI 1.01-2.13). Furthermore, Asians (OR 0.73; 95% CI 0.57-0.93) and Hispanics (OR 0.58; 95% CI 034-0.99) were less likely to have asthenospermia. Asians (OR 0.73; 95% CI 0.57-0.94) and Indo-Canadians (OR 0.58; 95% CI 0.35-0.99) were less likely to have teratozospermia. No differences were seen for vitality. No differences were seen for FSH levels, however, Asians (p<0.01) and Indo-Canadians (p<0.01) were more likely to have lower testosterone.

CONCLUSIONS

Our study illustrates that variations in semen analyses and hormones exist in men with infertility. This may provide insight into the workup and management for infertile men from different ethnicities.

Evaluation of markers out of the steroid profile for the screening of testosterone misuse. Part II: Intramuscular administration

In the fight against doping, the introduction of alternative markers to the steroid profile can be considered as an effective approach to improve the screening capabilities for the detection of testosterone (T) misuse. The aim of this study was to evaluate the potential of several T metabolites (cysteinyl conjugated and glucuronoconjugated resistant to enzymatic hydrolysis) to detect both the transdermal and the intramuscular administration of T. In Part I of the study, we studied the potential of these metabolites for the detection of T transdermal administration. Results revealed that resistant glucuronides can be a suitable complement to the current steroid profile. In this, Part II, dedicated to the intramuscular administration, we studied the potential of cysteinyl conjugated, resistant glucuronoconjugated and 1-cyclopentenoylglycine (1-CPG) for the detection of a single intramuscular injection of T cypionate. Possible differences in the excretion profile of all markers were explored between individuals with low basal (n=6) and medium basal (n=6) values of the testosterone/epitestosterone ratio (T/E). The results showed that all tested markers presented low intra-individual stability in basal conditions. Despite this, all glucuronoconjugated markers and 1-CPG, but not the cysteinyl conjugated markers, provided detection windows that were similar or longer than those obtained by markers currently included in the steroid profile. Based on the results obtained from the 2 parts of this study and from previously reported data, the potential applicability and the limitations of including these markers in the steroid profile are discussed.

Evaluation of markers out of the steroid profile for the screening of testosterone misuse. Part I: Transdermal administration

Although the introduction by the World Anti-Doping Agency (WADA) of the steroid module of the athlete biological passport (ABP) marked an important step forward in the screening of testosterone (T) misuse, it still remains one of the most difficult challenges in doping control analysis. The urinary determination of alternative markers has been recently reported as a promising tool for improving the screening of T oral administration. However, their evaluation for other, commonly used, administration routes is still required. The main goal of this study is the evaluation of the potential of 2 groups of metabolites (cysteinyl conjugated and glucuronoconjugated) after transdermal and intramuscular administration of T. Their suitability was evaluated in individuals with both low basal (L-T/E) and medium basal (M-T/E) values of T/E. In this Part I, we evaluated the urinary excretion profile of these 2 groups of T metabolites after the administration of 3 doses of T gel to 12 volunteers (6 L-T/E and 6 M-T/E) for 3 consecutive days. For this purpose, 9 different concentration ratios (5 cysteinyl conjugated and 4 glucuronoconjugated markers) were studied. Both, the intra-individual variability and the detection windows (DW) obtained by each ratio were evaluated. Cysteinyl conjugates showed a general low intra-individual variability and DWs that were shorter than any other tested marker. Despite the relatively large intra-individual variability, the DWs reached by glucuronoconjugates (2-3 days) were similar to those obtained by markers currently included in the ABP. Overall; this evaluation advises for the introduction of additional glucuronoconjugated markers in the screening of transdermal T administration.

The relationship between dioxins exposure and risk of prostate cancer with steroid hormone and age in Vietnamese men

Although Vietnam's massive herbicide exposure in 1960s and 1970s was clearly injurious to health, not all causal relationships have been clarified. We therefore explored associations among dioxins, steroid hormones, age and prostate cancer risk in men. We compared serum levels of dioxin, steroid hormones and prostate specific antigen (PSA) in men aged 56-81years from herbicide-exposed hotspots (n=50) with those from non-sprayed regions (n=48). Mean serum levels of dioxin congeners in the hotspot group were 1.5-11.3 times higher than the non-sprayed group depending on specific compound. Levels of testosterone, estradiol and 3β-hydroxysteroid dehydrogenase (3β-HSD) activity in the hotspot group were also significantly higher than in non-sprayed group. Estradiol levels were significantly related to levels of several specific dioxin derivatives in both group. Significant positive correlations were also found between DHT and 1234678-HpCDD or 1234678-HpCDF; and between 3β-HSD activity and 123678-HxCDD, 123478-HxCDF, 123678-HxCDF, or HxCB#169. After adjusting for age, body mass index, and tobacco use, multiple linear regressions showed levels of dihydrotestosterone (DHT), estradiol, testosterone and 3β-HSD activity were not associated with dioxins in the two groups; however, levels of DHT, testosterone and 3β-HSD activity increased significantly with age in the hotspot group. The hotspot and non-sprayed groups did not significantly differ in PSA levels. But six of the hotspot subjects had PSA levels >3ng/mL, 3 of whom were suspected to have prostate cancer (PC) after digital rectal examination. Our findings suggest that dioxin exposure can lead to increased levels of several sex steroid hormones with age. The correlation of dioxin with steroid hormone levels and prostate cancer risk should be studied further.

Prostate-specific antigen response in black and white patients treated with abiraterone acetate for metastatic castrate-resistant prostate cancer

PURPOSE

Evidence suggests differences in androgen receptor AR signaling between black (B) and white (W) patients with prostate cancer, but pivotal trials of abiraterone acetate (AA) for patients with metastatic castration-resistant prostate cancer (mCRPC) enrolled few black patients, a population with a higher mortality from prostate cancer. Our primary objective was to determine differences in response to AA between B and W patients.

METHODS

We performed a retrospective case-control study of B vs. W patients treated with AA between May 1, 2008 and June 16, 2015 at Duke University Medical Center. Patients were identified (W control patients were matched 2:1 to B patients stratified based on previous docetaxel exposure) through pharmacy records and were eligible if treated with AA for metastatic castration-resistant prostate cancer. Patients with previous enzalutamide use were excluded. The primary objective was to compare the rate of≥90% prostate-specific antigen (PSA) decline from baseline between B vs. W patients. Secondary outcomes included comparing time on therapy, time to PSA progression, and overall survival among groups.

RESULTS

Baseline characteristics among patients (n = 45 B, n = 90 W) were identified; these included Karnofsky performance status, PSA, Gleason score, alkaline phosphatase, albumin, hemoglobin, lactate dehydrogenase, opiate use for pain, and metastatic sites. Baseline characteristics among groups were similar except for median hemoglobin (B = 11.4g/dl, W = 12.3g/dl). The proportion of B patients achieving a≥90% PSA level decline was 37.8% vs. 28.9% for W patients (P = 0.296). Statistically significant differences were found in the proportion of patients achieving a≥50% PSA level decline (B = 68.9%, W = 48.9% [P = 0.028]) and≥30% PSA level decline (B = 77.8%, W = 54.4% [P = 0.008]). Rates of primary abiraterone-refractory disease (PSA increase as best response) trended higher in W (31.1%) than in B (15.6%) patients (P = 0.052). Median treatment duration (B = 9.4 mo, W = 8.3 mo) did not differ (Wilcoxon P = 0.444). Median overall survival (B = 27.3 mo [95% CI: 13.9, not estimable], W = 24.8 mo [95% CI: 19, 31.6] [P = 0.669]) and median time to PSA progression (B = 11.0 mo [95% CI: 4.3, 18.0], W = 9.4 mo [95% CI: 6.2, 13.0] [P = 0.917]) did not differ.

CONCLUSIONS

Black patients may have a higher PSA response to AA than white patients. An ongoing prospective clinical study (NCT01940276) is evaluating outcomes between black and white patients treated with AA.

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.

Relationship Between Aerobic Fitness, the Serum IGF-1 Profiles of Healthy Young Adult African American Males, and Growth of Prostate Cancer Cells

The growth of prostate tumors is mediated by the bioavailability of androgens and insulin-like growth factors. This study tested the hypothesis that healthy young adult African American men exhibiting low aerobic capacity (fitness) have serum insulin-like growth Factor-1 (IGF-1) and testosterone levels that promote growth of prostate cancer cells. A cross-sectional data research design was used to study groups of 18- to 26-year-old healthy men exhibiting low and moderate aerobic fitness, based on their peak oxygen consumption (VO_2peak). The individual serum levels of IGF-1, IGF-1 binding protein-3 (IGFBP-3), and testosterone were measured. In vitro growth of androgen-dependent LNCaP prostate tumor cells was measured after incubation in culture medium fortified with each subject's serum. Aerobic capacity was significantly greater in the moderate-fitness group than in the low-fitness group without an intergroup difference in body mass index. The serum IGF-1 concentration was significantly higher in the low-fitness group in the absence of an intergroup difference in serum testosterone. The serum IGFBP-3 concentration was significantly lower in the low-fitness group. Prostate tumor cell growth was significantly greater in the cultures incubated in media containing the sera of the low-fitness group than in the sera of the moderate-fitness group. These findings suggest that moderate aerobic fitness in young adults may decrease the circulating levels of free IGF-1 and lower the potential to support growth of prostate cancer cells.

Current opinion on the role of testosterone in the development of prostate cancer: a dynamic model

BACKGROUND

Since the landmark study conducted by Huggins and Hodges in 1941, a failure to distinguish between the role of testosterone in prostate cancer development and progression has led to the prevailing opinion that high levels of testosterone increase the risk of prostate cancer. To date, this claim remains unproven.

PRESENTATION OF THE HYPOTHESIS

We present a novel dynamic mode of the relationship between testosterone and prostate cancer by hypothesizing that the magnitude of age-related declines in testosterone, rather than a static level of testosterone measured at a single point, may trigger and promote the development of prostate cancer.

TESTING THE HYPOTHESIS

Although not easily testable currently, prospective cohort studies with population-representative samples and repeated measurements of testosterone or retrospective cohorts with stored blood samples from different ages are warranted in future to test the hypothesis.

IMPLICATIONS OF THE HYPOTHESIS

Our dynamic model can satisfactorily explain the observed age patterns of prostate cancer incidence, the apparent conflicts in epidemiological findings on testosterone and risk of prostate cancer, racial disparities in prostate cancer incidence, risk factors associated with prostate cancer, and the role of testosterone in prostate cancer progression. Our dynamic model may also have implications for testosterone replacement therapy.

Hadza hunter-gatherer men do not have more masculine digit ratios (2D:4D)

OBJECTIVES

The ratio between the length of the second and the length of the fourth digit (2D:4D) is sexually dimorphic such that males of many species possess a lower ratio than females, particularly in the right hand. Still, men and women often exhibit overlapping 2D:4D ranges and the ratio is highly variable between populations. In order to further explore populational variability, we chose to analyze 2D:4D in the Hadza, a population of hunter-gatherers living in Tanzania.

MATERIALS AND METHODS

Data were collected separately by two researchers over the course of three years (1998, 2001, 2006) from 152 adult participants (male: n = 76, female: n = 76). Independent samples t-tests were used to explore sex differences, paired samples t-tests were used to explore directional effects within each sex, and linear regression and one-way ANOVA were used to test possible age effects.

RESULTS

In none of the years, or pooled (n = 152), did we find evidence that adult men have a lower 2D:4D than adult women. If anything, the data suggest that women in this population have a significantly lower right hand 2D:4D than men (P < 0.001, d = 0.57). In contrast, left hand 2D:4D did not exhibit a sex difference (P = 0.862, d = 0.03).

DISCUSSION

These findings challenge the current view that lower 2D:4D in men is a uniform characteristic of our species. Cross-populational variance in 2D:4D may be related to known patterns of hormonal variation resulting from both genetic and environmental mechanisms, though this relationship merits further investigation.

The value of middle phalangeal hair as an anthropometric marker: A review of the literature

Middle phalangeal hair (MPH) is a trait frequently examined in anthropological studies throughout the 20th century. MPH is found on the back of the middle segment of the fingers, excluding the thumb. Typically, researchers examined the presence and absence of hair in various populations, and described it in terms of age, ancestry, and sex. Recently MPH has been examined as a potential anthropometric indicator of: androgen levels, androgen-related side effects in women, gene homozygosity, and disease resistance. Given the potential value of this marker, the present paper provides a comprehensive overview of MPH and its associated characteristics (i.e., ethnicity, sex, age, and hormonal variations) and presents new data on the reliability of MPH assessment. Findings suggest that ethnicity, sex, and age need to be controlled in any studies examining MPH and its relationship with other variables. Two measures of MPH (i.e., presence/absence of MPH and actual hair count) are both acceptable to use in MPH assessment; and the use of a hand lens to examine MPH provides high reliability when MPH is assessed by expert raters. However, researchers should avoid participant self-assessment. Future avenues for research are suggested (e.g., measurement issues and studies on hormonal correlates in women). MPH could be useful in research or for clinical purposes as a possible non-invasive indicator of hormone levels or hormonal sensitivity, or of predisposition toward androgen-related or gene-homozygosity-related health issues or behaviors.

Testosterone trajectories and reference ranges in a large longitudinal sample of male adolescents

PURPOSE

Pubertal dynamics plays an important role in physical and psychological development of children and adolescents. We aim to provide reference ranges of plasma testosterone in a large longitudinal sample. Furthermore, we describe a measure of testosterone trajectories during adolescence that can be used in future investigations of development.

METHODS

We carried out longitudinal measurements of plasma testosterone in 2,216 samples obtained from 513 males (9 to 17 years of age) from the Avon Longitudinal Study of Parents and Children. We used integration of a model fitted to each participant's testosterone trajectory to calculate a measure of average exposure to testosterone over adolescence. We pooled these data with corresponding values reported in the literature to provide a reference range of testosterone levels in males between the ages of 6 and 19 years.

RESULTS

The average values of total testosterone in the ALSPAC sample range from 0.82 nmol/L (Standard Deviation [SD]: 0.09) at 9 years of age to 16.5 (SD: 2.65) nmol/L at 17 years of age; these values are congruent with other reports in the literature. The average exposure to testosterone is associated with different features of testosterone trajectories such as Peak Testosterone Change, Age at Peak Testosterone Change, and Testosterone at 17 years of age as well as the timing of the growth spurt during puberty.

CONCLUSIONS

The average exposure to testosterone is a useful measure for future investigations using testosterone trajectories to examine pubertal dynamics.

Racial Differences in Age-Related Variations of Testosterone Levels Among US Males: Potential Implications for Prostate Cancer and Personalized Medication

AIM

The magnitude of the age-related declines in testosterone rather than levels measured at single point in time may be related to the genesis of prostate cancer (PCa). We examined age-related variations of testosterone levels among black and white males, which may provide important insights into racial disparities in PCa incidence and mortality.

METHOD

We analyzed data from the 1999-2004 National Health and Nutritional Examination Survey to compare age-related variations in the testosterone levels of 355 black and 631 white males.

RESULT

Overall, between the ages of 12 and 15, black males had lower testosterone levels than white males. Testosterone levels increased rapidly with age and reached higher and earlier peak levels in black males compared to white males at 20-30 years of age. After reaching a peak level, testosterone levels declined earlier in blacks than in whites. Further analyses showed that black males had considerably higher levels of testosterone compared to white males aged 20-39 years after adjusting for covariates, including age, body mass index, cigarette smoking, physical activity, and waist circumference; however, no statistically significant differences were observed between the groups at any other age.

CONCLUSION

Our study revealed that testosterone levels in black males decrease substantially with increasing age compared to those in white males. This rapid drop in testosterone levels may contribute to racial disparities in PCa. Our findings also suggest that personalized medication for hormone replacement therapy may be necessary to avoid sudden drops in testosterone levels, particularly for black males.

Update on prostate cancer in black men within the UK

There is a wealth of evidence which can be traced back to the African transatlantic slave trade indicating that black men have a higher risk of prostate cancer compared to other ethnic groups. Migration to Westernised countries may have had little effect on the incidence of prostate cancer in this ethnic group; however, current evidence indicates that there are several complex factors that may contribute to this risk. Studies in the UK quote that black men are at 2-3 times the risk of prostate cancer in comparison to their Caucasian counterparts, with a 30% higher mortality rate. Caution should be taken prior to the interpretation of these results due to a paucity of research in this area, limited accurate ethnicity data, and lack of age-specific standardisation for comparison. Cultural attitudes towards prostate cancer and health care in general may have a significant impact on these figures, combined with other clinico-pathological associations. This update summarises new contributory research on this subject, highlighting the need to increase awareness and understanding of prostate cancer amongst high-risk communities and to support further robust research in this area by nominating a lead in cancer and ethnicity studies within the National Health Service.

Effects of prenatal alcohol exposure on testosterone and pubertal development

BACKGROUND

Animal models have demonstrated fetal alcohol-related disruptions in neuroendocrine function in the hypothalamic-pituitary-gonadal axis and downstream effects on pubertal development and sexual behavior in males and females, but little is known about these effects in humans. This study examined whether prenatal alcohol exposure is associated with alterations in testosterone during adolescence and whether it affects timing of pubertal development.

METHODS

The sample consisted of 265 African American adolescents from the Detroit Longitudinal Cohort Study for whom testosterone and/or pubertal development data were available. Subjects were offspring of women recruited at their first prenatal clinic visit to over represent moderate-to-heavy alcohol use, including a 5% random sample of low-level drinkers/abstainers. Mothers were interviewed at every prenatal visit about their alcohol consumption using a timeline follow-back approach and about their smoking and drug use and sociodemographic factors. At age 14 years, adolescents provided salivary samples, which were analyzed for testosterone (pg/ml), self-reported Tanner stages for pubertal development, and age at menarche (females).

RESULTS

Prenatal alcohol exposure was related to elevated testosterone concentrations for males and females but not to changes in Tanner stages or age at menarche, after controlling for confounders. In regression models stratified by alcohol exposure, the expected relation between testosterone and pubic hair development was seen among males with light-to-no prenatal alcohol exposure, but not among those with moderate-to-heavy prenatal alcohol exposure. This interaction between testosterone and prenatal alcohol exposure was confirmed in multivariable models including an alcohol exposure group × testosterone interaction term and potential confounders.

CONCLUSIONS

This study is the first to show a relation between prenatal alcohol exposure and increased testosterone during adolescence and evidence of decreased testosterone responsiveness in tissues related to pubertal development in humans. Further studies examining androgen receptor expression and other hormonal and cellular factors affecting pubertal development may reveal important mechanisms underlying these teratogenic effects of alcohol exposure.

"Linearity assessment methods for sex steroid hormones and carrier proteins among men in the National Health and Nutrition Examination Survey (NHANES III)"

INTRODUCTION

It has been hypothesized that racial disparities among several diseases are explained by differences in testosterone (T), 17-β estradiol (E), sex hormone binding globulin (SHBG) and albumin (A) levels, yet epidemiologic results have been mixed. Statistical advice regarding appropriate adjustment methods for carrier proteins of sex steroid hormones in the literature is scant. Therefore, we investigated different adjustment methods for carrier proteins.

METHODS

Data for 1496 men, >17 years from the Third National Health and Nutrition Examination Survey (NHANES III) 1988-91 were used to analyze linearity between sex hormones and carrier proteins by examining correlation, plots, and regression models. The statistical importance of age, body mass index (BMI), and race/ethnicity were examined for changes in results by the adjustment method.

RESULTS

T was weakly correlated with SHBG and A (r-squared, 0.25, 0.13, respectively) and E was weakly negatively correlated with A (p<0.0001), but not SHBG (p<0.1799). Based on the model residual plots and r-squared, the categorical model performed better than linear models. Regression coefficients for age, BMI, and race/ethnicity groups using quotient (e.g., T/A and E/A) models differed from continuous and categorical models.

CONCLUSION

Choosing an appropriate adjustment for carrier proteins is important to prevent bias in analyses and inconsistency in findings across studies. Linearity between variables should not be assumed when adjusting models, and should be conducted and reported. An independent categorical carrier protein variable is recommended in analysis exploring factors predicting sex hormone levels, although statistical testing should always be employed.

Racial variation in sex steroid hormone concentration in black and white men: a meta-analysis

Sex steroid hormones are associated with chronic diseases and mortality with risk associations that differ between racial and ethnic groups. However, it is currently unclear whether sex steroid hormone levels differ between black and white men. The aim of this study was to assess racial variation in circulating testosterone, free testosterone, sex hormone-binding globulin (SHBG) and estradiol levels in men. We searched PubMed for articles comparing circulating hormones in black and white men. A meta-analysis was performed using weighted mean differences (WMD) to compare hormones levels between black and white men. Fifteen eligible studies were identified; three did not report adjusted means. After age adjustment, free testosterone levels were significantly higher in black than in white men (WMD = 4.07 pg/mL, 95% CI 1.26, 6.88). Depending on the free testosterone concentration in white men, this WMD translates into a racial difference ranging from 2.5 to 4.9%. Total testosterone (WMD = 0.10 ng/mL, 95% CI -0.02, 0.22), estradiol (WMD = 0.67 pg/mL, 95% CI -0.04, 1.38) and SHBG (WMD = -0.45 nmol/L, 95% CI -1.75, 0.85) concentrations did not differ comparing blacks with whites. After adjustment for age, black men have a modestly but significantly 2.5 to 4.9% higher free testosterone level than white men. Based on previous studies on effects of sex steroid hormones on risk of chronic diseases or mortality, this modest difference is unlikely to explain racial differences in disease risk.

Reference ranges for urinary levels of testosterone and epitestosterone, which may reveal gonadal function, in a Korean male population

Cannabis, or marijuana, the most commonly used illicit drug in the world, has been shown to be responsible for suppressing the production and secretion of androgens, particularly testosterone. However, despite such findings in animals, the chronic effects of marijuana use on human endocrine systems have proved to be inconsistent. Here, we investigated the reference ranges of urinary levels of testosterone (T) and epitestosterone (E) as well as their metabolic ratio of T/E in a Korean male population (n=337), which would enable an evaluation of abnormal changes in steroid metabolism induced by habitually administered cannabis. The T/E ratio was significantly decreased in the marijuana group (n=18), while the urinary testosterone concentrations were also tended to decrease. This study is the first to provide data for the reference values of two urinary androgens and T/E values among control Korean males, and, furthermore, suggests that the T/E ratio, though not testosterone levels, might be used to understand the suppression of human male gonadal function affected by smoking marijuana.

Angiotensin-converting enzyme insertion/deletion polymorphism contributes high risk for chronic kidney disease in Asian male with hypertension--a meta-regression analysis of 98 observational studies

Background

Associations between angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphisms and chronic kidney disease (CKD) have been extensively studied, with most studies reporting that individuals with the D allele have a higher risk. Although some factors, such as ethnicity, may moderate the association between ACE I/D polymorphisms and CKD risk, gender-dependent effects on the CKD risk remain controversial.

Objectives

This study investigated the gender-dependent effects of ACE I/D polymorphisms on CKD risk.

Data sources

PubMed, the Cochrane library, and EMBASE were searched for studies published before January 2013.

Study eligibility criteria, participants, and interventions

Cross-sectional surveys and case–control studies analyzing ACE I/D polymorphisms and CKD were included. They were required to match the following criteria: age >18 years, absence of rare diseases, and Asian or Caucasian ethnicity.

Study appraisal and synthesis methods

The effect of carrying the D allele on CKD risk was assessed by meta-analysis and meta-regression using random-effects models.

Results

Ethnicity [odds ratio (OR): 1.24; 95% confidence interval (CI): 1.08–1.42] and hypertension (OR: 1.55; 95% CI: 1.04–2.32) had significant moderate effects on the association between ACE I/D polymorphisms and CKD risk, but they were not significant in the diabetic nephropathy subgroup. Males had higher OR for the association between ACE I/D polymorphisms and CKD risk than females in Asians but not Caucasians, regardless of adjustment for hypertension (p<0.05). In subgroup analyses, this result was significant in the nondiabetic nephropathy group. Compared with the I allele, the D allele had the highest risk (OR: 3.75; 95% CI: 1.84–7.65) for CKD in hypertensive Asian males.

Conclusions and implications of key findings

The ACE I/D polymorphisms may incur the highest risk for increasing CKD in hypertensive Asian males.

Testosterone levels are negatively associated with fatherhood [corrected] in males, but positively related to offspring count in fathers

Variation in testosterone (T) is thought to affect the allocation of effort between reproductive and parenting strategies. Here, using a large sample of elderly American men (n = 754) and women (n = 669) we examined the relationship between T and self-reported parenthood, as well as the relationship between T and number of reported children. Results supported previous findings from the literature, showing that fathers had lower T levels than men who report no children. Furthermore, we found that among fathers T levels were positively associated with the number of children a man reports close to the end of his lifespan. Results were maintained when controlling for a number of relevant factors such as time of T sampling, participant age, educational attainment, BMI, marital status and reported number of sex partners. In contrast, T was not associated with either motherhood or the number of children women had, suggesting that, at least in this sample, T does not influence the allocation of effort between reproductive and parenting strategies among women. Findings from this study contribute to the growing body of literature suggesting that, among men, pair bonding and paternal care are associated with lower T levels, while searching and acquiring sex partners is associated with higher T levels.

Racial/ethnic differences in serum sex steroid hormone concentrations in US adolescent males

OBJECTIVE

Contrary to the hypothesis that the racial/ethnic disparity in prostate cancer has a hormonal basis, we did not observe a difference in serum testosterone concentration between non-Hispanic black and white men in the Third National Health and Nutrition Examination Survey (NHANES III), although non-Hispanic black men had a higher estradiol level. Unexpectedly, Mexican-American men had the highest testosterone level. Next, we evaluated whether the same patterns are observed during adolescence, the time of prostate maturation.

METHODS

We measured serum testosterone, estradiol, and sex hormone-binding globulin (SHBG) by immunoassay in 134 males aged 12-19 in NHANES III. Mean concentrations were compared by race/ethnicity adjusting for age, Tanner stage, percent body fat, waist, physical activity, tobacco smoke, and the other hormones.

RESULTS

After multivariable adjustment, in the 12-15-year-old males, testosterone concentration was lower in non-Hispanic blacks than whites (p = 0.043), SHBG concentration did not significantly differ between the two groups. Mexican-Americans had the highest testosterone (versus non-Hispanic black: p = 0.002) and lowest SHBG (versus non-Hispanic white: p = 0.010; versus non-Hispanic black: p = 0.047) concentrations. Estradiol concentration was lower in non-Hispanic blacks (p = 0.11) and Mexican-Americans (p = 0.033) compared with non-Hispanic whites. After multivariable adjustment, in the 16-19-year-old males, testosterone, estradiol, and SHBG concentrations did not differ between non-Hispanic blacks and whites. Mexican-Americans had the highest testosterone concentration (versus non-Hispanic white: p = 0.08), but did not differ from the other groups on estradiol and SHBG concentrations. In both age groups, these patterns were generally present, but less pronounced after adjusting for age and Tanner stage only.

CONCLUSION

In adolescent males, non-Hispanic blacks did not have a higher testosterone concentration than non-Hispanic whites, and Mexican-Americans had the highest testosterone concentration, patterns similar to adult males.

Androgen receptor-target genes in african american prostate cancer disparities

The incidence and mortality rates of prostate cancer (PCa) are higher in African American (AA) compared to Caucasian American (CA) men. To elucidate the molecular mechanisms underlying PCa disparities, we employed an integrative approach combining gene expression profiling and pathway and promoter analyses to investigate differential transcriptomes and deregulated signaling pathways in AA versus CA cancers. A comparison of AA and CA PCa specimens identified 1,188 differentially expressed genes. Interestingly, these transcriptional differences were overrepresented in signaling pathways that converged on the androgen receptor (AR), suggesting that the AR may be a unifying oncogenic theme in AA PCa. Gene promoter analysis revealed that 382 out of 1,188 genes contained cis-acting AR-binding sequences. Chromatin immunoprecipitation confirmed STAT1, RHOA, ITGB5, MAPKAPK2, CSNK2A,1 and PIK3CB genes as novel AR targets in PCa disparities. Moreover, functional screens revealed that androgen-stimulated AR binding and upregulation of RHOA, ITGB5, and PIK3CB genes were associated with increased invasive activity of AA PCa cells, as siRNA-mediated knockdown of each gene caused a loss of androgen-stimulated invasion. In summation, our findings demonstrate that transcriptional changes have preferentially occurred in multiple signaling pathways converging (“transcriptional convergence”) on AR signaling, thereby contributing to AR-target gene activation and PCa aggressiveness in AAs.

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.

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.

A cross-sectional study of the association of age, race and ethnicity, and body mass index with sex steroid hormone marker profiles among men in the National Health and Nutrition Examination Survey (NHANES III)

OBJECTIVES

Since sex hormone markers are metabolically linked, examining sex steroid hormones singly may account for inconsistent findings by age, race/ethnicity and body mass index (BMI) across studies. First, these markers were statistically combined into profiles to account for the metabolic relationship between markers. Then, the relationships between sex steroid hormone profiles and age, race/ethnicity and BMI were explored in multinomial logistic regression models.

DESIGN

Cross-sectional survey.

SETTING

The US Third National Health and Nutrition Examination Survey (NHANES III).

PARTICIPANTS

1538 Men, >17 years.

PRIMARY OUTCOME MEASURE

Sex hormone profiles.

RESULTS

Cluster analysis was used to identify four statistically determined profiles with Blom-transformed T, E, sex hormone binding globulin (SHBG), and 3-α diol G. We used these four profiles with multinomial logistic regression models to examine differences by race/ethnicity, age and BMI. Mexican American men >50 years were associated with the profile that had lowest T, E and 3-α diol G levels compared to other profiles (p<0.05). Non-Hispanic Black, overweight (25-29.9 kg/m(2)) and obese (>30 kg/m(2)) men were most likely to be associated with the cluster with the lowest SHBG (p<0.05).

CONCLUSION

The associations of sex steroid hormone profiles by race/ethnicity are novel, while the findings by age and BMI groups are largely consistent with observations from single hormone studies. Future studies should validate these hormone profile groups and investigate these profiles in relation to chronic diseases and certain cancers.

Physiological stress responses to the 2008 U.S. presidential election: The role of policy preferences and social dominance orientation

This study examines physiological stress responses to the 2008 U.S. presidential election. The week before and after Election Day, participants provided three daily saliva samples, assayed for cortisol (a principal “stress hormone”) and testosterone. Results revealed that, on Election Day, all participants on average and Republicans in particular exhibited stunted cortisol and testosterone rhythms, perhaps reflecting participants’ anticipation. After Election Day, participants’ political affiliation was not a strong predictor of physiological responses. Their social dominance orientation—that is, their tolerance of social inequalities—was predictive of responses. Those higher in social dominance orientation had higher cortisol and testosterone morning values. These changes suggest that individuals higher in social dominance orientation were distressed but ready to fight back. The present findings add to an emerging body of work showing that sociopolitical differences can influence biological systems relevant to health and behavior.

Interactions among genes, tumor biology and the environment in cancer health disparities: examining the evidence on a national and global scale

Cancer incidence and mortality rates show great variations across nations and between population groups. These variations are largely explained by differences in age distribution, diet and lifestyle, access to health care, cultural barriers and exposure to carcinogens and pathogens. Cancers caused by infections are significantly more common in developing than developed countries, and they overproportionally affect immigrant populations in the USA and other countries. The global pattern of cancer is not stagnant. Instead, it is dynamic because of fluctuations in the age distribution of populations, improvements in cancer prevention and early detection in affluent countries and rapid changes in diet and lifestyle in parts of the world. For example, increased smoking rates have caused tobacco-induced cancers to rise in various Asian countries, whereas reduced smoking rates have caused these cancers to plateau or even begin to decline in Western Europe and North America. Some population groups experience a disproportionally high cancer burden. In the USA and the Caribbean, cancer incidence and mortality rates are excessively high in populations of African ancestry when compared with other population groups. The causes of this disparity are multifaceted and may include tumor biological and genetic factors and their interaction with the environment. In this review, we will discuss the magnitude and causes of global cancer health disparities and will, with a focus on African-Americans and selected cancer sites, evaluate the evidence that genetic and tumor biological factors contribute to existing cancer incidence and outcome differences among population groups in the USA.

Associations between longitudinal changes in serum estrogen, testosterone, and bioavailable testosterone and changes in benign urologic outcomes

Some men have rapid increases in benign prostatic enlargement and lower urinary tract symptoms (LUTS), and it is not clear how sex steroid hormones contribute to the rates of change in these urologic outcomes. Therefore, the authors conducted a population-based cohort study of 648 men residing in Olmsted County, Minnesota, from 1990 to 2007, to examine associations between baseline sex steroid hormones, the rate of change in these hormones, and the rates of change in LUTS, maximum urinary flow rate, and prostate volume. Annual changes in hormone levels and urologic outcomes were calculated using mixed-effects regression models. Associations between hormone variables and rates of change in urologic outcomes were assessed with linear regression models. Higher baseline estradiol levels and rapid declines in estradiol over time were associated with rapid increases in LUTS and rapid decreases in maximum flow rate. Lower baseline bioavailable testosterone levels and more rapid declines in bioavailable testosterone were associated with more rapid increases in prostate volume. These results suggest that both absolute sex steroid hormone levels and the rates at which the levels change may be important in the development of urologic conditions in aging men.

Endogenous steroid profiling in the athlete biological passport

The Athlete Biological Passport (ABP) is an individual electronic document that collects data regarding a specific athlete that is useful in differentiating between natural physiologic variations of selected biomarkers and deviations caused by artificial manipulations. A subsidiary of the endocrine module of the ABP, that which here is called Athlete Steroidal Passport (ASP), collects data on markers of an altered metabolism of endogenous steroidal hormones measured in urine samples. The ASP aims to identify not only doping with anabolic-androgenic steroids, but also most indirect steroid doping strategies such as doping with estrogen receptor antagonists and aromatase inhibitors. Development of specific markers of steroid doping, use of the athlete's previous measurements to define individual limits, with the athlete becoming his or her own reference, the inclusion of heterogeneous factors such as the UDPglucuronosyltransferase B17 genotype of the athlete, the knowledge of potentially confounding effects such as heavy alcohol consumption, the development of an external quality control system to control analytical uncertainty, and finally the use of Bayesian inferential methods to evaluate the value of indirect evidence have made the ASP a valuable alternative to deter steroid doping in elite sports. The ASP can be used to target athletes for gas chromatography/combustion/ isotope ratio mass spectrometry (GC/C/IRMS) testing, to withdraw temporarily the athlete from competing when an abnormality has been detected, and ultimately to lead to an antidoping infraction if that abnormality cannot be explained by a medical condition. Although the ASP has been developed primarily to ensure fairness in elite sports, its application in endocrinology for clinical purposes is straightforward in an evidence-based medicine paradigm.

Circulating steroid hormones in prostate carcinogenesis. Part 1 – Androgens

The aim of this review is to identify circulating steroids associated with prostate cancer (PCa) in bibliographic reports. First, we summarize chronological reports comparing circulating steroid levels in men with a high risk of PCa, such as African-Americans (AAs), with men having a lower risk. Higher testosterone plasma levels in young AA men have been reported. However, the difference between AAs and Caucasians decreases with age. When measured, dihydrotestosterone (DHT) was found to be higher in AAs; however, these results must be taken with caution, as immunological assay of this steroid is difficult. Second, we summarize chronological reports concerning circulating steroids assayed in blood samples drawn several years before a diagnosis of PCa was made, compared to controls. These nested case-control studies did not lead to straightforward conclusions regarding an increase in circulating testosterone. However, large collaborative studies showed a trend of a decrease in plasma sex hormone binding globulin, consequently an increase in bioavailable plasma testosterone in PCa. These nested case-control studies failed to associate plasma DHT levels with PCa risk. Third, we summarize numerous chronological publications relating plasma concentrations, measured at the time of PCa diagnosis. Numerous results showed a decrease in plasma testosterone levels in aggressive PCa (high Gleason score, advanced stage with positive surgical margins). Testosterone levels returned to normal several months after prostatectomy. All plasma hormone assay levels were always carried out using immunological methods. We recommend replacing this methodology by mass spectrometry coupled with gas chromatography or liquid chromatography in these epidemiologic studies.

Proteomics of rat prostate lobes treated with 2-N-hydroxylamino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 5alpha-dihydrotestosterone, individually and in combination

Epidemiological and preclinical studies suggest that environmental factors, hormonal responses and lifestyle, including diet and physical inactivity, are likely contributors to the initiation and progression of prostate cancer in humans. Although the effects of the food derived carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and/or testosterone (T) in the development of prostate cancer in the rat have been reported, the extent to which such compounds impact cancer related proteins is not clear. Knowledge of cancer-related proteins impacted by PhIP and/or T is prerequisite to developing novel strategies to early-detect prostate cancer. Male F344 rats were sacrificed, the prostate tissue isolated and separated into dorsolateral, ventral, and anterior lobes. The lobes were cultured and treated with 10(-3) M NHPhIP and/or 10(-7) M DT for 24 h. NHPhIP is the genotoxic form of PhIP and DT is the more proliferative form of T. We used 2D-DIGE and LC/MS/MS technologies to study the proteome of the prostate lobes to determine if the compounds will trigger detectable changes in expression of cancer-related proteins. Analysis of the signals from 2D-DIGE revealed that about 10% of proteins were differentially expressed in the NHPhIP and/or DT treatments compared to controls. Eight candidate protein spots detected by 2D-DIGE in at least two out of three lobes showed > or =2-fold difference between treated and control samples. Five out of the eight spots contained single proteins; including, phospholipase Calpha (PLP-Calpha), Rab7, SAR1a, ribosomal protein S7 (RPS7), and nucleoside diphosphate kinase (NDPK). A survey of the literature shows that NDPK expression is altered in human cancers, including prostate cancer. Thus, we validated the altered expression of NDPK by Western blot analysis. The concordance between 2D-DIGE and Western blot analysis was 80%. The results of this study demonstrate, for the first time, that the combination of 2D-DIGE and LC/MS/MS is a powerful tool for identification of proteins in the prostate tissue that are altered by environmental carcinogens and/or hormones.

Apocrine sweat gland obstruction by antiperspirants allowing transdermal absorption of cutaneous generated hormones and pheromones as a link to the observed incidence rates of breast and prostate cancer in the 20th century

Breast and prostate cancer share similarities and likely represent homologous cancers in females and males, respectively. The role of hormones such as testosterone and estrogen in carcinogenesis is well established. Despite worldwide research efforts, the pathogenesis of these diseases is largely not well understood. Personal care products containing estrogens or xenoestrogens have raised concern as a breast cancer risk, especially in young African-American women. In the United States (US) there is a parallel rise in the incidence in breast and prostate cancer compared to selected non-hormone dependent tumors. Observed US and global breast and prostate cancer incidence increases were occurring before exogenous hormone replacement and xenoestrogen exposure were commonplace. An unintentional, inadvertent, and long term hormone exposure may occur from transdermal absorption of sex hormones and pheromones (androgens) from axillary apocrine sweat gland obstruction by aluminum-based antiperspirants. The global rise in antiperspirant use parallels rises in breast and prostate cancer incidence and mortality rates. A multi-disciplinary literature based set of evidence is presented on how such a link is possible, to prompt confirmatory investigations in the pursuit of unmet needs in breast and prostate cancer etiology and prevention.