Explaining racial differences in prostate cancer in the United States: sociology or biology?

Mechanism of Antitumor Effects of Saffron in Human Prostate Cancer Cells

Prostate cancer is the most common cancer and the second leading cause of cancer deaths among men in the USA. Several studies have demonstrated the antitumor properties of saffron in different types of cancers, including prostate cancer. The oral administration of saffron extract has been reported to have antitumor effects on aggressive prostate-cancer-cell-line-derived xenografts in nude male mice. The objective of this study was to carry out in vitro studies of saffron-treated prostate cancer cells to ascertain the effects of saffron on key intermediates in prostate carcinogenesis. Our studies demonstrated the significant inhibition of cell proliferation for androgen-sensitive prostate cancer cell lines via apoptotic pathways. We also demonstrate the statistically significant down-regulation of DNA methyltransferases (COMT, MGMT, EHMT2, and SIRT1 deacetylase) in saffron-treated prostate cancer cells. In addition, saffron-treated prostate cancer cells displayed a statistically significant dysregulation of DNA repair intermediates (WRN, p53, RECQ5, MST1R, and WDR70) in a time-dependent manner. Furthermore, Western blot analysis demonstrated that saffron treatment induced changes in the expression of other key genes (DNMT1, DNMT3b, MBD2, CD44, HDAC3, c-Myc, NF-kB, TNFα, AR, N-RAS, and PTEN) in prostate cancer cells. Collectively, our findings demonstrate the important mechanisms by which saffron mediates anti-tumor properties in prostate cancer. These findings suggest that the use of saffron supplements alongside standard treatment protocols may yield beneficial effects for individuals with prostate cancer.

Association of TP53 Single Nucleotide Polymorphisms with Prostate Cancer in a Racially Diverse Cohort of Men

Growing evidence indicates the involvement of a genetic component in prostate cancer (CaP) susceptibility and clinical severity. Studies have reported the role of germline mutations and single nucleotide polymorphisms (SNPs) of TP53 as possible risk factors for cancer development. In this single institutional retrospective study, we identified common SNPs in the TP53 gene in AA and CA men and performed association analyses for functional TP53 SNPs with the clinico-pathological features of CaP. The SNP genotyping analysis of the final cohort of 308 men (212 AA; 95 CA) identified 74 SNPs in the TP53 region, with a minor allele frequency (MAF) of at least 1%. Two SNPs were non-synonymous in the exonic region of TP53: rs1800371 (Pro47Ser) and rs1042522 (Arg72Pro). The Pro47Ser variant had an MAF of 0.01 in AA but was not detected in CA. Arg72Pro was the most common SNP, with an MAF of 0.50 (0.41 in AA; 0.68 in CA). Arg72Pro was associated with a shorter time to biochemical recurrence (BCR) (p = 0.046; HR = 1.52). The study demonstrated ancestral differences in the allele frequencies of the TP53 Arg72Pro and Pro47Ser SNPs, providing a valuable framework for evaluating CaP disparities among AA and CA men.

Prostate cancer risk in men of differing genetic ancestry and approaches to disease screening and management in these groups

Prostate cancer is the second most common solid tumour in men worldwide and it is also the most common cancer affecting men of African descent. Prostate cancer incidence and mortality vary across regions and populations. Some of this is explained by a large heritable component of this disease. It has been established that men of African and African Caribbean ethnicity are predisposed to prostate cancer (PrCa) that can have an earlier onset and a more aggressive course, thereby leading to poorer outcomes for patients in this group. Literature searches were carried out using the PubMed, EMBASE and Cochrane Library databases to identify studies associated with PrCa risk and its association with ancestry, screening and management of PrCa. In order to be included, studies were required to be published in English in full-text form. An attractive approach is to identify high-risk groups and develop a targeted screening programme for them as the benefits of population-wide screening in PrCa using prostate-specific antigen (PSA) testing in general population screening have shown evidence of benefit; however, the harms are considered to weigh heavier because screening using PSA testing can lead to over-diagnosis and over-treatment. The aim of targeted screening of higher-risk groups identified by genetic risk stratification is to reduce over-diagnosis and treat those who are most likely to benefit.

Race-specific prostate cancer outcomes in a cohort of military health care beneficiaries undergoing surgery: 1990-2017

Background

There is substantial variability in prostate cancer (PCa) mortality rates across Caucasian American (CA), African American (AA), Asian, and Hispanic men; however, these estimates are unable to disentangle race or ethnicity from confounding factors. The current study explores survival differences in long‐term PCa outcomes between self‐reported AA and CA men, and examines clinicopathologic features across self‐reported CA, AA, Asian, and Hispanic men.

Methods

This retrospective cohort study utilized the Center for Prostate Disease Research (CPDR) Multi‐center National Database from 1990 to 2017. Subjects were consented at military treatment facilities nationwide. AA, CA, Asian, or Hispanic men who underwent radical prostatectomy (RP) for localized PCa within the first year of diagnosis were included in the analyses. Time from RP to biochemical recurrence (BCR), BCR to metastasis, and metastasis to overall death were evaluated using Kaplan–Meier unadjusted estimation curves and adjusted Cox proportional hazards regression.

Results

This study included 7067 men, of whom 5155 (73%) were CA, 1468 (21%) were AA, 237 (3%) were Asian, and 207 (3%) were Hispanic. AA men had a significantly decreased time from RP to BCR compared to CA men (HR = 1.25, 95% CI = 1.06–1.48, p = 0.01); however, no difference was observed between AA and CA men for a time from BCR to metastasis (HR = 0.73, 95% CI = 0.39–1.33, p = 0.302) and time from metastasis to overall death (HR = 0.67, 95% CI = 0.36–1.26, p = 0.213).

Conclusions

In an equal access health care setting, AA men had a shorter survival time from RP to BCR, but comparable survival time from BCR to metastasis and metastasis to overall death.

Race-specific prostate cancer outcomes in a cohort of low and favorable-intermediate risk patients who underwent external beam radiation therapy from 1990 to 2017

BACKGROUND

Previous research exploring the role of race on prostate cancer (PCa) outcomes has demonstrated greater rates of disease progression and poorer overall survival for African American (AA) compared to Caucasian American (CA) men. The current study examines self-reported race as a predictor of long-term PCa outcomes in patients with low and favorable-intermediate risk disease treated with external beam radiation therapy (EBRT).

METHODS

This retrospective cohort study examined patients who were consented to enrollment in the Center for Prostate Disease Research Multicenter National Database between January 01, 1990 and December 31, 2017. Men self-reporting as AA or CA who underwent EBRT for newly diagnosed National Comprehensive Cancer Network-defined low or favorable-intermediate risk PCa were included. Dependent study outcomes included: biochemical recurrence-free survival, (ii) distant metastasis-free survival, and (iii) overall survival. Each outcome was modeled as a time-to-event endpoint using race-stratified Kaplan-Meier estimation curves and multivariable Cox proportional hazards analysis.

RESULTS

Of 840 men included in this study, 268 (32%) were AA and 572 (68%) were CA. The frequency of biochemical recurrence, distant metastasis, and deaths from any cause was 151 (18.7%), 29 (3.5%), and 333 (39.6%), respectively. AA men had a significantly younger median age at time of EBRT and slightly higher biopsy Gleason scores. Multivariable Cox proportional hazards analyses demonstrated no racial differences in any of the study endpoints.

CONCLUSIONS

These findings reveal no racial disparity in PCa outcomes for AA compared to CA men, in a long-standing, longitudinal cohort of patients with comparable access to cancer care.

MicroRNA-mRNA Regulatory Network Mediates Activation of mTOR and VEGF Signaling in African American Prostate Cancer

African American (AA) men exhibit 1.6-fold higher prostate cancer (PCa) incidence and 2.4-fold higher mortality rates compared to European American (EA) men. In addition to socioeconomic factors, emerging evidence suggests that intrinsic biological differences may explain part of PCa disparities. In this study, we applied microRNA (miRNA)-driven bioinformatics to evaluate whether differential miRNA-mRNA regulatory networks play a role in promoting the AA PCa disparities. 10 differentially expressed miRNAs were imported to mirPath V.3 algorithm, leading to identification of 58 signaling pathways differentially regulated in AA PCa versus EA PCa. Among these pathways, we particularly focused on mTOR and VEGF signaling, where we identified 5 reciprocal miRNA-mRNA pairings: miR-34a-5p/HIF1A, miR-34a-5p/PIK3CB, miR-34a-5p/IGFBP2, miR-99b-5p/MTOR and miR-96-5p/MAPKAPK2 in AA PCa versus EA PCa. RT-qPCR validation confirmed that miR-34a-5p, miR-99b-5p and MAPKAPK2 were downregulated, while miR-96-5p, IGFBP2, HIF1A, PIK3CB and MTOR were upregulated in AA PCa versus EA PCa cells. Transfection of miRNA mimics/antagomir followed by RT-qPCR and Western blot analysis further verified that IGFBP2, HIF1A and PIK3CB are negatively regulated by miR-34a-5p, whereas MTOR and MAPKAPK2 are negatively regulated by miR-99b-5p and miR-96-5p, respectively, at mRNA and protein levels. Targeting reciprocal pairings by miR-34a-5p mimic, miR-99b-5p mimic or miR-96-5p antagomir downregulates HIF1α, PI3Kβ, mTOR, IGFBP2 but upregulates MAPKAPK2, subsequently reducing cell proliferation and sensitizing docetaxel-induced cytotoxicity in PCa cells. These results suggest that miRNA-mRNA regulatory network plays a critical role in AA PCa disparities, and targeting these core miRNA-mRNA pairings may reduce PCa aggressiveness and overcome the chemoresistance in AA patients.

Interactions Between Obesity and One-Carbon Metabolism Genes in Predicting Prostate Cancer Outcomes Among White and Black Patients

BACKGROUND

One-carbon metabolism genes are linked to several cancers, but the association with prostate cancer (PCa) is less clear. Studies examining the relationship have not accounted for obesity, a risk factor for advanced PCa and altered methylation patterns. We hypothesized that obesity could moderate the association between one-carbon metabolism genes and PCa outcomes.

METHODS

We conducted secondary data analyses of the Study of Clinical Outcomes, Risk and Ethnicity. Obesity was included as a primary exposure and modifier (interacting with genetic polymorphisms) in the analytic models. We used logistic regression to determine associations of common one-carbon metabolism genotypes with odds of high stage (T3/T4) and high grade (Gleason score ≥ 7). We used Cox regression to examine associations of genotypes with biochemical recurrence.

RESULTS

There were 808 patients (632 White and 176 Black.) Among White men, we observed associations of TCN2_R259P with increased odds of high stage (OR = 0.64, 95% CI = 0.41-1.00), but no significant interactions with obesity. Among Black men, the SCL19A1_61bpdel and CBS_68bpINS variants were associated with high grade (OR = 2.61, 95% CI = 1.39-4.89 and OR = 0.29, 95% CI = 0.09-0.91, respectively.) Both the CBS_68bpINS and MTHFR_E429A variants interacted with obesity in Black men, where the highest risk for biochemical failure and odds of high grade, respectively, occurred among obese patients with variants.

CONCLUSIONS

We observed associations of one-carbon metabolism genes with different associations by race. We also observed interactions with obesity related to PCa outcomes in Black men only. Therefore, the involvement of one-carbon metabolism on PCa was dependent upon obesity status for Black men. These novel results could help identify patients that might benefit from effective weight management targeting one-carbon metabolism effects.

RASAL2 suppresses the proliferative and invasive ability of PC3 prostate cancer cells

The RAS protein activator like 2 (RASAL2) negatively regulates RAS proto-oncogene which is activated by high mutation rate in cancer. Thus, RASAL2 expression could potentially limit the function of RAS in prostate cancer (PCa). Genome-wide DNA methylation analysis demonstrated that RASAL2 is differentially hypermethylated in PCa tissues compared to benign prostate tissues. The PCR analysis of RASAL2 mRNA transcript showed differential expression in a panel of prostate cell lines with most PCa showing lower RASAL2 expression compared to benign prostatic epithelial cells. In PCa PC3 cells, the ectopic expression of RASAL2 significantly inhibited cell proliferation and invasion and induced an S phase plus G2/M phase cell cycle arrest. Ingenuity Pathway Analysis (IPA) demonstrated a cross talk between RASAL2 and TNFα, a key cytokine in immune signaling pathway that is relevant in PCa. Over-expression of RASAL2 downregulated TNFα expression whereas the knockdown of RASAL2 caused increased expression of TNFα. Taken together, our data demonstrates tumor suppressor role for RASAL2 in human PCa cells, despite increased RAS oncogenic activity. Our observation provides a new mechanistic insight of RASAL2 expression in aberrant Ras expression and immune signaling in PCa cells suggesting a potential novel therapeutic target for PCa.

Age-Adjusted Reference Values for Prostate Specific Antigen - A Systematic Review and Meta-Analysis

OBJECTIVES

To systematically evaluates the evidence on ethnic differences in age-adjusted reference values of PSA.

MATERIALS AND METHODS

In concordance with the Preferred Reporting Items for Systematic Review and Meta-analysis statement, a review of English articles using Medline, Embase and Cochrane databases, from inception to December 2019 was conducted. Studies that reported the PSA upper reference value as 95th percentile of the cohort distribution, in healthy men aged 40 to 79, were included. Methodological quality was assessed with a modified version of the Agency for Healthcare Research and Quality checklist for cross-sectional studies.

RESULTS

Forty-three studies examining 325,514 participants were included in the analysis. These were published between 1993 and 2018. Majority were prospective observational studies and reported the reference values in ten-year age intervals. Only five reports directly compared ethnic differences in PSA values. Due to missing data, six studies were not considered in the quantitative synthesis. For the remainder (37/43), heterogeneity in PSA reference values was considerable (Higgin's index = 99.2%), with age and ethnicity being the sole identified significant contributors. Accordingly, the pooled upper limits for PSA reference values were 2.1, 3.2, 4.9 and 6.5 ng/ml for men in their 40 s, 50 s, 60 s, and 70 s, respectively.

CONCLUSION

Moderate quality evidence suggest that upper PSA reference limits increased with age and significant ethnic differences were present.

Trends in the use of active surveillance and treatments in Medicare beneficiaries diagnosed with localized prostate cancer

BACKGROUND

The treatment for men diagnosed with localized prostate cancer has changed over time given the increased attention to the harms associated with over-diagnosis and the development of protocols for active surveillance.

METHODS

We examined trends in the treatment of men diagnosed with localized prostate cancer between 2004 and 2015, using the most recently available data from Surveillance, Epidemiology, and End Results Program (SEER)-Medicare. Patients were stratified by Gleason score, age, and race groups.

RESULTS

The use of active surveillance increased from 22% in 2004-2005 to 50% in 2014-2015 for patients with a Gleason score of 6 or below and increased from 9% in 2004-2005 to 13% in 2014-2015 for patients with a Gleason score of 7 or above. Patients with a Gleason score of 7 or above had increased use of intensity-modulated radiation therapy and prostatectomy, especially among patients aged 75 years and older. Among patients with a Gleason score of 6 or below non-Hispanic black men were less likely to undergo active surveillance than non-Hispanic white men.

CONCLUSIONS

There has been a large increase in the use of active surveillance among men with a Gleason score of 6 or below. However, non-Hispanic black men with a Gleason score of 6 or below are less likely to receive active surveillance.

Association of Health-Care System with Prostate Cancer-Specific Mortality in African American and Non-Hispanic White Men

BACKGROUND

Disparities in prostate cancer-specific mortality (PCSM) between African American and non-Hispanic White (White) patients have been attributed to biological and systemic factors. We evaluated drivers of these disparities in the Surveillance, Epidemiology and End Results (SEER) national registry and an equal-access system, the Veterans Health Administration (VHA).

METHODS

We identified African American and White patients diagnosed with prostate cancer between 2004-2015 in SEER (N = 311,691) and the VHA (N = 90,749). We analyzed the association between race and metastatic disease at presentation using multivariable logistic regression adjusting for sociodemographic factors, and PCSM using sequential competing-risks regression adjusting for disease and sociodemographic factors.

RESULTS

The median follow-up was 5.3 years in SEER and 4.7 years in the VHA. African American men were more likely than White men to present with metastatic disease in SEER (adjusted odds ratio = 1.23, 95% confidence interval [CI] = 1.17-1.30), but not in the VHA (adjusted odds ratio = 1.07, 95% CI = 0.98-1.17). African American versus White race was associated with an increased risk of PCSM in SEER (subdistribution hazard ratio [SHR] = 1.32, 95% CI = 1.10-1.60), but not in the VHA (SHR = 1.00, 95% CI: 0.93-1.08). Adjusting for disease extent, PSA, and Gleason score eliminated the association between race and PCSM in SEER (aSHR 1.04, 95% CI 0.93-1.16).

CONCLUSIONS

Racial disparities in PCSM were present in a nationally representative registry, but not in an equal-access healthcare system, due to differences in advanced disease at presentation. Strategies to increase healthcare access may bridge the racial disparity in outcomes. Longer follow-up is needed to fully assess mortality outcomes.Disparities between African American and non-Hispanic White (White) patients in cancer-specific mortality have been described across numerous cancer types and healthcare systems[1-5]. The survival gap between African American and White patients with prostate cancer has been well-characterized, with two-fold higher prostate cancer-specific mortality (PCSM) rates among African American patients depending on the setting[1, 6-10]. This disparity has been attributed to differences in prostate cancer biology in African American men, in addition to systemic factors in mediating this disparity, such as differential access to healthcare, Prostate-Specific Antigen (PSA) screening, and distrust in the healthcare system[1, 11-16].The Veterans Health Administration (VHA) is a relatively equal-access healthcare system that treats a large, ethnically diverse population of veterans. The Surveillance, Epidemiology and End Results (SEER) program is a national cancer registry program that collects data from the general United States (US) population. The goals of the present investigation were to 1) Compare PCSM between African American and White men within SEER and the VHA and 2) Identify modifiable system-level contributors to these disparities. We hypothesized that PCSM would be comparable among African American and White men in an equal-access setting, the VHA, but not in a national registry, SEER, and that this disparity in SEER would be in part driven by more advanced disease at presentation.

Dying To Be Men: Masculinity and Early Cancer Detection Among Nigerian Men

Cancer incidence and mortality in Nigeria are increasing at an alarming rate, especially among Nigerian men. Despite the numerous public health campaigns and education on the importance of early cancer detection in Nigeria, there exist high rate of fatal/advanced stage cancer diagnoses among Nigerian men, even among affluent Nigerian men. However, there is limited information on patterns of cancer screening and psychosocial predictors of early cancer detection behaviors among Nigerian men. In this cross-sectional study, we examined demographic and psychosocial factors influencing early cancer detection behaviors among Nigerian men. Participants (N = 143; Mage = 44.73) responded to survey assessing: masculinity, attachment styles, current and future cancer detection behaviors, and sociodemographic characteristics. We found that among the participants studied, education, masculinity and anxious attachment were significantly associated with current cancer detection behaviors. Additionally, education and anxious attachment were significantly associated with future cancer detection behaviors. Our finding is best served for clinicians and public health professionals, especially those in the field of oncology in Sub-Saharan Africa. Also, the study may be used as a groundwork for future research and health intervention programs targeting men in Sub-Saharan Africa.

Lack of Racial Survival Differences in Metastatic Prostate Cancer in National Cancer Data Base (NCDB): A Different Finding Compared to Non-metastatic Disease

Background: Inconsistent findings have been reported in the literature regarding racial differences in survival outcomes between African American and white patients with metastatic prostate cancer (mPCa). The current study utilized a national database to determine whether racial differences exist among the target population to address this inconsistency.

Methods: This study retrospectively reviewed prostate cancer (PCa) patient data (N = 1,319,225) from the National Cancer Database (NCDB). The data were divided into three groupings based on the metastatic status: (1) no metastasis (N = 318,291), (2) bone metastasis (N = 29,639), and (3) metastases to locations other than bone, such as brain, liver, or lung (N = 952). Survival probabilities of African American and white PCa patients with bone metastasis were examined through parametric proportional hazards Weibull models and Bayesian survival analysis. These results were compared to patients with no metastasis or other types of metastases.

Results: No statistically supported racial disparities were observed for African American and white men with bone metastasis (p = 0.885). Similarly, there were no racial disparities in survival for those men suffering from other metastases (liver, lung, or brain). However, racial disparities in survival were observed among the two racial groups with non-metastatic PCa (p < 0.001) or when metastasis status was not taken into account (p < 0.001). The Bayesian analysis corroborates the finding.

Conclusion: This research supports our previous findings and shows that there are no racial differences in survival outcomes between African American and white patients with mPCa. In contrast, racial disparities in the survival outcome continue to exist among non-metastatic PCa patients. Further research is warranted to explain this difference.

Clinical outcomes in men of diverse ethnic backgrounds with metastatic castration-resistant prostate cancer

BACKGROUND

We have shown previously in multivariable analysis that black men had 19% lower risk of death than white men with metastatic castration-resistant prostate cancer (mCRPC) treated with a docetaxel and prednisone (DP)-based regimen. The primary goal of this analysis was to compare progression-free survival (PFS), biochemical PFS, ≥50% decline in prostate-specific antigen (PSA) from baseline and objective response rate (ORR) in white, black and Asian men with mCRPC treated with a DP-based regimen.

PATIENTS AND METHODS

Individual patient data from 8820 mCRPC men randomized on nine phase III trials to a DP-containing regimen were combined. Race used in the analysis was based on self-report. End points were PFS, biochemical PSA, ≥50% decline in PSA from baseline and ORR. The proportional hazards and the logistic regression models were employed to assess the prognostic importance of race in predicting outcomes adjusting for established prognostic factors.

RESULTS

Of 8820 patients, 7528 (85%) were white, 500 (6%) were black, 424 were Asian (5%) and 368 (4%) had race unspecified. Median PFS were 8.3 [95% confidence interval (CI) 8.2-8.5], 8.2 (95% CI 7.4-8.8) and 8.3 (95% CI 7.6-8.8) months in white, black and Asian men, respectively. Median PSA PFS were 9.9 (95% CI 9.7-10.4), 8.5 (95% CI 8.0-10.3) and 11.1 (95% CI 9.9-12.5) months in white, black and Asian men, respectively.

CONCLUSIONS

We observed no differences in clinical outcomes by race and ethnic groups in men with mCRPC enrolled on these phase III clinical trials with DP.

Overall Survival of Black and White Men With Metastatic Castration-Resistant Prostate Cancer Treated With Docetaxel

PURPOSE

Several studies have reported that among patients with localized prostate cancer, black men have a shorter overall survival (OS) time than white men, but few data exist for men with advanced prostate cancer. The primary goal of this analysis was to compare the OS in black and white men with metastatic castration-resistant prostate cancer (mCRPC) who were treated in phase III clinical trials with docetaxel plus prednisone (DP) or a DP-containing regimen.

METHODS

Individual participant data from 8,820 men with mCRPC randomly assigned in nine phase III trials to DP or a DP-containing regimen were combined. Race was based on self-report. The primary end point was OS. The Cox proportional hazards regression model was used to assess the prognostic importance of race (black v white) adjusted for established risk factors common across the trials (age, prostate-specific antigen, performance status, alkaline phosphatase, hemoglobin, and sites of metastases).

RESULTS

Of 8,820 men, 7,528 (85%) were white, 500 (6%) were black, 424 (5%) were Asian, and 368 (4%) were of unknown race. Black men were younger and had worse performance status, higher testosterone and prostate-specific antigen, and lower hemoglobin than white men. Despite these differences, the median OS was 21.0 months (95% CI, 19.4 to 22.5 months) versus 21.2 months (95% CI, 20.8 to 21.7 months) in black and white men, respectively. The pooled multivariable hazard ratio of 0.81 (95% CI, 0.72 to 0.91) demonstrates that overall, black men have a statistically significant decreased risk of death compared with white men ( P < .001).

CONCLUSION

When adjusted for known prognostic factors, we observed a statistically significant increased OS in black versus white men with mCRPC who were enrolled in these clinical trials. The mechanism for these differences is not known.

Does race predict the development of metastases in men who receive androgen-deprivation therapy for a biochemical recurrence after radical prostatectomy?

BACKGROUND

In this study among men who underwent radical prostatectomy (RP), African American men (AAM) were 28% more likely to develop recurrent disease compared with Caucasian men (CM). However, among those who had nonmetastatic, castration-resistant prostate cancer (CRPC), race did not predict metastases or overall survival. Whether race predicts metastases among men who receive androgen-deprivation therapy (ADT) after a biochemical recurrence (BCR) (ie, before CRPC but after BCR) is untested.

METHODS

The authors identified 595 AAM and CM who received ADT for a BCR that developed after RP between 1988 and 2015 in the Shared Equal-Access Regional Cancer Hospital (SEARCH) database. Univariable and multivariable Cox models were used to test the association between race and the time from ADT to metastases. Secondary outcomes included the time to CRPC, all-cause mortality, and prostate cancer-specific mortality.

RESULTS

During a median follow-up of 66 months after ADT, 62 of 354 CM (18%) and 38 of 241 AAM (16%) developed metastases. AAM were younger at the time they received ADT (63 vs 67 years; P < .001), had received ADT in a more recent year (2008 vs 2006; P < .001), had higher prostate-specific antigen levels at RP (11.1 vs 9.2 ng/mL; P < .001), lower pathologic Gleason scores (P = .004), and less extracapsular extension (38% vs 48%; P = .022). On multivariable analysis, there was no association between race and metastases (hazard radio, 1.20; P = .45) or any of the other secondary outcomes (all P > .5).

CONCLUSIONS

Among veterans who received ADT post-BCR after RP, race was not a predictor of metastases or other adverse outcomes. The current findings suggest that research efforts to understand racial differences in prostate cancer biology should focus on early stages of the disease (ie, closer to the time of diagnosis).

Dysregulated gene expression predicts tumor aggressiveness in African-American prostate cancer patients

Molecular mechanisms underlying the health disparity of prostate cancer (PCa) have not been fully determined. In this study, we applied bioinformatic approach to identify and validate dysregulated genes associated with tumor aggressiveness in African American (AA) compared to Caucasian American (CA) men with PCa. We retrieved and analyzed microarray data from 619 PCa patients, 412 AA and 207 CA, and we validated these genes in tumor tissues and cell lines by Real-Time PCR, Western blot, immunocytochemistry (ICC) and immunohistochemistry (IHC) analyses. We identified 362 differentially expressed genes in AA men and involved in regulating signaling pathways associated with tumor aggressiveness. In PCa tissues and cells, NKX3.1, APPL2, TPD52, LTC4S, ALDH1A3 and AMD1 transcripts were significantly upregulated (p < 0.05) compared to normal cells. IHC confirmed the overexpression of TPD52 (p = 0.0098) and LTC4S (p < 0.0005) in AA compared to CA men. ICC and Western blot analyses additionally corroborated this observation in PCa cells. These findings suggest that dysregulation of transcripts in PCa may drive the disparity of PCa outcomes and provide new insights into development of new therapeutic agents against aggressive tumors. More studies are warranted to investigate the clinical significance of these dysregulated genes in promoting the oncogenic pathways in AA men.

Correlating blood-based DNA methylation markers and prostate cancer risk in African-American men

The objective of this work was to investigate the clinical significance of promoter gene DNA methylation changes in whole blood from African-American (AA) men with prostate cancer (PCa). We used high throughput pyrosequencing analysis to quantify percentage DNA methylation levels in a panel of 8 genes (RARβ2, TIMP3, SPARC, CDH13, HIN1, LINE1, CYB5R2 and DRD2) in blood DNA obtained from PCa and non-cancerous controls cases. Correlations of methylation status and various clinicopathological features were evaluated. Six genes tested achieved significant difference in DNA methylation levels between the PCa compared to control cases (P < 0.05). The TIMP3 loci demonstrated significant correlation of DNA methylation with age for all cases analyzed (p < 0.05). We observed an inverse correlation between CDH13 methylation (p = 0.045; r = -0.21) and serum vitamin D level whereas TIMP3 methylation (p = 0.021; r = -0.24) and DRD2 methylation (p = 0.056; r = -0.201) showed inverse correlation with supplementary vitamin D in the cancer cases. We also observed a direct correlation between methylation of RARβ2 (p = 0.0036; r = 0.293) and SPARC (p = 0.0134; r = 0.20) loci with PSA level in the controls but not the cancer cases. In addition, alcohol cases significantly correlated with higher RARβ2 methylation (p = 0.0314) in comparison with non-alcohol cases. Furthermore, we observed an inverse correlation of DRD2 methylation (p = 0.0349; r = -0.343) and Gleason score. Our data suggests that promoter methylation occurred more frequently in the blood of AA PCa and is associated with various clinicopathological features in AA men with PCa.

Prostate cancer risk factors in black and white men in the NIH-AARP Diet and Health Study

BACKGROUND

There are few prospective studies comparing race-specific associations between diet, nutrients, and health-related parameters, and prostate cancer risk.

METHODS

Race-specific prostate cancer risk associations were examined among men in the National Institutes of Health (NIH)-AARP Diet and Health Study. We identified 1417 cases among black men (209 advanced), and 28,845 among white men (3898 advanced). Cox proportional hazards regression models estimated hazard ratios (HRs) and 95% confidence intervals (CIs). We also evaluated the cumulative change in the HR for black race following adjustment for each factor.

RESULTS

Race-specific prostate cancer associations were similar in black and white men across disease subtypes only for history of diabetes (overall : HR = 0.77, 95% CI: 0.65-0.90 and HR = 0.72, 95% CI: 0.69-0.76, respectively; P_interaction = 0.66). By contrast, there was a positive risk association with height for white men  and  inverse for black men (P_interaction: non-advanced = 0.01; advanced = 0.04). This difference remained among men with at least 2 years of follow-up for non-advanced (P_interaction = 0.01), but not advanced disease (P_interaction = 0.24); or after adjustment for prostate cancer screening (non-advanced P_interaction = 0.53, advanced P_interaction = 0.31). The only other evidence of interaction with race was observed for dietary vitamin D intake and non-advanced disease, but only after adjustment for screening (P_interaction = 0.02). Cumulative adjustment for each factor increased the HR for black race by 32.9% for overall cancer and 12.4% for advanced disease.

CONCLUSIONS

Our data suggest few of the dietary, nutrient, and health-related factors associated with prostate cancer risk in predominantly non-Hispanic white men were associated with risk in black men, and adjustment for these factors widen the black-white difference in risk. Larger studies of black men, particularly with prospective data, are needed to help identify risk factors relevant to this population.

The effect of socioeconomic status, race, and insurance type on newly diagnosed metastatic prostate cancer in the United States (2004-2013)

BACKGROUND

Understanding the characteristics of men who initially present with metastatic prostate cancer (mPCa) can better enable directed improvement initiatives. The objective of this study was to assess the relationship between socioeconomic status (SES) and newly diagnosed mPCa.

MATERIALS METHODS

All men diagnosed with PCa in the National Cancer Data Base from 2004 to 2013 were identified. Characteristics of men presenting with and without metastatic disease were compared. A 4-level composite metric of SES was created using Census-based income and education data. Multivariable logistic regression was used to evaluate the association between SES, race/ethnicity, and insurance and the risk of presenting with mPCa at the time of diagnosis.

RESULTS

Of 1,034,754 patients diagnosed with PCa, 4% had mPCa at initial presentation. Lower SES (first vs. fourth quartile; odds ratio [OR] = 1.39, 95% CI: 1.35-1.44), black and Hispanic race/ethnicity (vs. white; OR = 1.47, 95% CI: 1.43-1.51 and OR = 1.22, 95% CI: 1.17-1.28, respectively), and having Medicaid or no insurance (vs. Medicare or private; OR = 3.91, 95% CI: 3.78-4.05) were each independently associated with higher odds of presenting with mPCa after adjusting for all other covariates.

CONCLUSIONS

Lower SES, race/ethnicity, and having Medicaid or no insurance were each independently associated with higher odds of presenting with metastases at the time of PCa diagnosis. Our findings may partially explain current PCa outcomes disparities and inform future efforts to reduce disparities.

Race and risk of metastases and survival after radical prostatectomy: Results from the SEARCH database

BACKGROUND

Black race is associated with prostate cancer (PC) diagnosis and poor outcome. Previously, the authors reported that black men undergoing radical prostatectomy (RP) in equal-access hospitals had an increased risk of biochemical disease recurrence (BCR), but recurrences were equally aggressive as those occurring in white men. The authors examined the association between race and long-term outcomes after RP.

METHODS

Data regarding 1665 black men (37%) and 2791 white men (63%) undergoing RP were analyzed. Using Cox models, the authors tested the association between race and BCR, BCR with a prostate-specific antigen (PSA) doubling time <9 months (aggressive disease recurrence), metastases, PC-specific death, and overall death.

RESULTS

At a median follow-up of 102 months, 1566 men (35%) developed BCR, 217 men (5%) experienced aggressive disease recurrence, 193 men (4%) developed metastases, and 1207 men (27%) had died, 107 of whom (2%) died of PC. White men were older and had a lower preoperative PSA level, a lower biopsy and pathological grade group, and more capsular penetration but less seminal vesicle invasion and positive surgical margins versus black men (all P<.05). Black men were found to have a more recent surgery year (P<.001). On univariable analysis, black race was associated with increased BCR (P = .003) and reduced overall death (P = .017). On multivariable analysis, black race was not found to be associated with BCR (hazard ratio [HR], 1.07; P = .26), aggressive recurrence (HR, 1.14; P = .42), metastasis (HR, 1.24; P = .21), PC-specific death (HR, 1.03; P = .91), or overall death (HR, 1.03; P = .67).

CONCLUSIONS

Among men undergoing RP at equal-access centers, although black men were found to have an increased risk of BCR, they had similar risks of aggressive disease recurrence, metastasis, and PC-specific death compared with white men, and the risk of BCR was found to be similar after controlling for risk parameters. Longer follow-up is needed to confirm these findings. Cancer 2017;123:4199-4206. © 2017 American Cancer Society.

Carotenoid intake and adipose tissue carotenoid levels in relation to prostate cancer aggressiveness among African-American and European-American men in the North Carolina-Louisiana prostate cancer project (PCaP)

BACKGROUND

Associations between carotenoid intake and prostate cancer (CaP) incidence have varied across studies. This may result from combining indolent with aggressive disease in most studies. This study examined whether carotenoid intake and adipose tissue carotenoid levels were inversely associated with CaP aggressiveness.

METHODS

Data on African-American (AA, n = 1,023) and European-American (EA, n = 1,079) men with incident CaP from North Carolina and Louisiana were analyzed. Dietary carotenoid intake was assessed using a detailed-food frequency questionnaire (FFQ), and abdominal adipose tissue samples were analyzed for carotenoid concentrations using high-performance liquid chromatography. Multivariable logistic regression was used in race-stratified analyses to calculate odds ratios (ORs) and 95% confidence intervals (95%CI) comparing high aggressive CaP with low/intermediate aggressive CaP.

RESULTS

Carotenoid intake differed significantly between AAs and EAs, which included higher intake of lycopene among EAs and higher β-cryptoxanthin intake among AAs. Comparing the highest and lowest tertiles, dietary lycopene was associated inversely with high aggressive CaP among EAs (OR = 0.55, 95%CI: 0.34-0.89, Ptrend  = 0.02), while an inverse association was observed between dietary β-cryptoxanthin intake and high aggressive CaP among AAs (OR = 0.56, 95%CI: 0.36-0.87, Ptrend  = 0.01). Adipose tissue α-carotene and lycopene (cis + trans) concentrations were higher among EAs than AAs, and marginally significant inverse linear trends were observed for adipose α-carotene (Ptrend  = 0.07) and lycopene (Ptrend  = 0.11), and CaP aggressiveness among EAs only.

CONCLUSIONS

These results suggest that diets high in lycopene and β-cryptoxanthin may protect against aggressive CaP among EAs and AAs, respectively. Differences in dietary behaviors may explain the observed racial differences in associations. Prostate 76:1053-1066, 2016. © 2016 Wiley Periodicals, Inc.

MNX1 Is Oncogenically Upregulated in African-American Prostate Cancer

Incidence and mortality rates for prostate cancer are higher in African-American (AA) men than in European-American (EA) men, but the biologic basis for this disparity is unclear. We carried out a detailed analysis of gene expression changes in prostate cancer compared with their matched benign tissues in a cohort of AA men and compared them with existing data from EA men. In this manner, we identified MNX1 as a novel oncogene upregulated to a relatively greater degree in prostate cancer from AA men. Androgen and AKT signaling play a central role in the pathogenesis of prostate cancer and we found that both of these signaling pathways increased MNX1 expression. MNX1 in turn upregulated lipid synthesis by stimulating expression of SREBP1 and fatty acid synthetase. Our results define MNX1 as a novel targetable oncogene increased in AA prostate cancer that is associated with aggressive disease. Cancer Res; 76(21); 6290-8. ©2016 AACR.

Clinical Use of PCA3 and TMPRSS2:ERG Urinary Biomarkers in African-American Men Undergoing Prostate Biopsy

PURPOSE

Prostate specific antigen has decreased performance characteristics for the detection of prostate cancer in African-American men. We evaluated urinary PCA3 and TMPRSS2:ERG in a racially diverse group of men.

MATERIALS AND METHODS

After institutional review board approval, post-examination urine was prospectively collected before prostate biopsy. PCA3 and TMPRSS2:ERG RNA copies were quantified using transcription mediated amplification assays (Hologic, San Diego, California). Prediction models were created using standard of care variables (age, race, family history, prior biopsy, abnormal digital rectal examination) plus prostate specific antigen. Decision curve analysis was performed to compare the net benefit of PCA3 and TMPRSS2:ERG.

RESULTS

Of 304 patients 182 (60%) were African-American and 139 (46%) were diagnosed with prostate cancer (69% African-American). PCA3 and TMPRSS2:ERG scores were greater in men with prostate cancer, 3 or more cores, 33.3% or more cores, greater than 50% involvement of greatest biopsy core and Epstein significant prostate cancer (p <0.01). PCA3 added to the standard of care plus prostate specific antigen model for the detection of any prostate cancer in the overall cohort (0.747 vs 0.677, p <0.0001) in African-American men only (0.711 vs 0.638, p=0.0002) and nonAfrican-American men (0.781 vs 0.732, p=0.0016). PCA3 added to the model for the prediction of high grade prostate cancer for the overall cohort (0.804 vs 0.78, p=0.0002) and African-American men only (0.759 vs 0.717, p=0.0003) but not nonAfrican-American men. Decision curve analysis demonstrated improvement with the addition of PCA3. For African-American men TMPRSS2:ERG did not improve concordance statistics for the detection of prostate cancer.

CONCLUSIONS

For African-American men urinary PCA3 improves the ability to predict the presence of any and high grade prostate cancer. However, the TMPRSS2:ERG urinary assay does not add significantly to standard tools.

The role of mesenchymal stem cells in promoting the transformation of androgen-dependent human prostate cancer cells into androgen-independent manner

Mesenchymal stem cells (MSCs) play an important role in the development of human prostate cancer (PCa). However, the role of MSCs in the transformation of androgen-dependent human PCa cells into androgen-independent manner has been poorly understood. In this study, we investigated the underlying mechanism of MSCs in promoting PCa cells from androgen-dependent into androgen-independent manner. Firstly, we demonstrated that MSCs could affect the transformation of androgen-dependent human PCa cells into androgen-independent manner in vivo and in vitro. Then we found a substantial expression of TGF-β in MSCs. TGF-β blockade could significantly inhibit the promotive function of MSCs in PCa cells. Besides that, we also demonstrated androgen might inhibit the expression of TGF-β in MSCs. Furthermore, we found that either overexpression of SSEA-4 or the number of SSEA-4 positive MSCs in PCa tissues was associated with a shorter cancer-free survival interval (CFSI) and a worse overall survival (OS). Our results suggest that androgen blockade treatment in clinical PCa therapy may elicit the expression of TGF-β in MSCs, which will result in the transformation of androgen-dependent human PCa cells into androgen-independent manner.

Germline Variants in Asporin Vary by Race, Modulate the Tumor Microenvironment, and Are Differentially Associated with Metastatic Prostate Cancer

PURPOSE

Prostate cancers incite tremendous morbidity upon metastatic growth. We previously identified Asporin (ASPN) as a potential mediator of metastatic progression found within the tumor microenvironment. ASPN contains an aspartic acid (D)-repeat domain and germline polymorphisms in D-repeat-length have been associated with degenerative diseases. Associations of germline ASPN D polymorphisms with risk of prostate cancer progression to metastatic disease have not been assessed.

EXPERIMENTAL DESIGN

Germline ASPN D-repeat-length was retrospectively analyzed in 1,600 men who underwent radical prostatectomy for clinically localized prostate cancer and in 548 noncancer controls. Multivariable Cox proportional hazards models were used to test the associations of ASPN variations with risk of subsequent oncologic outcomes, including metastasis. Orthotopic xenografts were used to establish allele- and stroma-specific roles for ASPN D variants in metastatic prostate cancer.

RESULTS

Variation at the ASPN D locus was differentially associated with poorer oncologic outcomes. ASPN D14 [HR, 1.72; 95% confidence interval (CI), 1.05-2.81, P = 0.032] and heterozygosity for ASPN D13/14 (HR, 1.86; 95% CI, 1.03-3.35, P = 0.040) were significantly associated with metastatic recurrence, while homozygosity for the ASPN D13 variant was significantly associated with a reduced risk of metastatic recurrence (HR, 0.44; 95% CI, 0.21-0.94, P = 0.035) in multivariable analyses. Orthotopic xenografts established biologic roles for ASPN D14 and ASPN D13 variants in metastatic prostate cancer progression that were consistent with patient-based data.

CONCLUSIONS

We observed associations between ASPN D variants and oncologic outcomes, including metastasis. Our data suggest that ASPN expressed in the tumor microenvironment is a heritable modulator of metastatic progression.

Risk of prostate cancer in African-American men: Evidence of mixed effects of dietary quercetin by serum vitamin D status

BACKGROUND

African-American (AA) men experience higher rates of prostate cancer (PCa) and vitamin D (vitD) deficiency than white men. VitD is promoted for PCa prevention, but there is conflicting data on the association between vitD and PCa. We examined the association between serum vitD and dietary quercetin and their interaction with PCa risk in AA men.

METHODS

Participants included 90 AA men with PCa undergoing treatment at Howard University Hospital (HUH) and 62 controls participating in HUH's free PCa screening program. We measured serum 25-hydroxy vitD [25(OH)D] and used the 98.2 item Block Brief 2000 Food Frequency Questionnaires to measure dietary intake of quercetin and other nutrients. Case and control groups were compared using a two-sample t-test for continuous risk factors and a Fisher exact test for categorical factors. Associations between risk factors and PCa risk were examined via age-adjusted logistic regression models.

RESULTS

Interaction effects of dietary quercetin and serum vitD on PCa status were observed. AA men (age 40-70) with normal levels of serum vitD (>30 ng/ml) had a 71% lower risk of PCa compared to AA men with vitD deficiency (OR = 0.29, 95%CI: 0.08-1.03; P = 0.055). In individuals with vitD deficiency, increased dietary quercetin showed a tendency toward lower risk of PCa (OR = 0.91, 95%CI: 0.82-1.00; P = 0.054, age-adjusted) while men with normal vitD were at elevated risk (OR = 1.23, 95%CI: 1.04-1.45).

CONCLUSION

These findings suggest that AA men who are at a higher risk of PCa may benefit more from vitD intake, and supplementation with dietary quercetin may increase the risk of PCa in AA men with normal vitD levels. Further studies with larger populations are needed to better understand the impact of the interaction between sera vitD levels and supplementation with quercetin on PCa in AA men.

Dietary, supplement, and adipose tissue tocopherol levels in relation to prostate cancer aggressiveness among African and European Americans: The North Carolina-Louisiana Prostate Cancer Project (PCaP)

BACKGROUND

Controversies remain over the safety and efficacy of vitamin E (i.e., α-tocopherol) supplementation use for the prevention of prostate cancer (CaP); however, associations of different tocopherol forms and CaP aggressiveness have yet to be examined.

METHODS

This study examined whether food intake of tocopherols, vitamin E supplement use, and adipose tissue biomarkers of tocopherol were associated with CaP aggressiveness among African-American (AA, n = 1,023) and European-American (EA, n = 1,079) men diagnosed with incident CaP. Dietary tocopherols were estimated from a food frequency questionnaire, supplement use from questionnaire/inventory, and biomarkers from abdominal adipose samples measured using high-performance liquid chromatography. Odds ratios (ORs) and 95% confidence intervals (95%CIs) were estimated from logistic regression comparing high-aggressive CaP to low/intermediate aggressive CaP, adjusting for covariates.

RESULTS

Dietary intakes of α-and δ-tocopherol were related inversely to CaP aggressiveness among EAs [OR (95%CI), highest versus lowest quartile: α-tocopherol, 0.34 (0.17-0.69), P(trend)  = 0.006; δ-tocopherol, 0.45 (0.21-0.95) P(trend)  = 0.007]. Inverse associations between dietary and supplemental α-tocopherol and CaP aggressiveness were observed among AAs, though these did not reach statistical significance [OR (95%CI), highest versus lowest quartile: dietary α-tocopherol, 0.58 (0.28-1.19), P(trend)  = 0.20; supplemental α-tocopherol, 0.64 (0.31-1.21) P(trend)  = 0.15]. No significant association was observed between adipose tocopherol levels and CaP aggressiveness [OR (95%CI), highest versus lowest quartiles of α-tocopherol for EAs 1.43 (0.66-3.11) and AAs 0.66 (0.27-1.62)].

CONCLUSIONS

The inverse associations observed between dietary sources of tocopherols and CaP aggressiveness suggests a beneficial role of food sources of these tocopherols in CaP aggressiveness.

Genome-wide differentially methylated genes in prostate cancer tissues from African-American and Caucasian men

Increasing evidence suggests that aberrant DNA methylation changes may contribute to prostate cancer (PCa) ethnic disparity. To comprehensively identify DNA methylation alterations in PCa disparity, we used the Illumina 450K methylation platform to interrogate the methylation status of 485,577 CpG sites focusing on gene-associated regions of the human genome. Genomic DNA from African-American (AA; 7 normal and 3 cancers) and Caucasian (Cau; 8 normal and 3 cancers) was used in the analysis. Hierarchical clustering analysis identified probe-sets unique to AA and Cau samples, as well as common to both. We selected 25 promoter-associated novel CpG sites most differentially methylated by race (fold change > 1.5-fold; adjusted P < 0.05) and compared the β-value of these sites provided by the Illumina, Inc. array with quantitative methylation obtained by pyrosequencing in 7 prostate cell lines. We found very good concordance of the methylation levels between β-value and pyrosequencing. Gene expression analysis using qRT-PCR in a subset of 8 genes after treatment with 5-aza-2'-deoxycytidine and/or trichostatin showed up-regulation of gene expression in PCa cells. Quantitative analysis of 4 genes, SNRPN, SHANK2, MST1R, and ABCG5, in matched normal and PCa tissues derived from AA and Cau PCa patients demonstrated differential promoter methylation and concomitant differences in mRNA expression in prostate tissues from AA vs. Cau. Regression analysis in normal and PCa tissues as a function of race showed significantly higher methylation prevalence for SNRPN (P = 0.012), MST1R (P = 0.038), and ABCG5 (P < 0.0002) for AA vs. Cau samples. We selected the ABCG5 and SNRPN genes and verified their biological functions by Western blot analysis and siRNA gene knockout effects on cell proliferation and invasion in 4 PCa cell lines (2 AA and 2 Cau patients-derived lines). Knockdown of either ABCG5 or SNRPN resulted in a significant decrease in both invasion and proliferation in Cau PCa cell lines but we did not observe these remarkable loss-of-function effects in AA PCa cell lines. Our study demonstrates how differential genome-wide DNA methylation levels influence gene expression and biological functions in AA and Cau PCa.

Racial disparities in oncologic outcomes after radical prostatectomy: long-term follow-up

OBJECTIVE

To report race-based outcomes after radical prostatectomy (RP) in a cohort stratified by National Comprehensive Cancer Network (NCCN) risk category with updated follow-up.

MATERIALS AND METHODS

Studies describing racial disparities in outcomes after RP are conflicting. We studied 15,993 white and 1634 African American (AA) pretreatment-naïve men who underwent RP at our institution (1992-2013) with complete preoperative and pathologic data. Pathologic outcomes were compared between races using appropriate statistical tests; biochemical recurrence (BCR) for men with complete follow-up was compared using multivariate models that controlled separately for preoperative and postoperative covariates.

RESULTS

Very low- and low-risk AA men were more likely to have positive surgical margins (P <.01), adverse pathologic features (P <.01), and be upgraded at RP (P <.01). With a median follow-up of 4.0 years after RP, AA race was an independent predictor of BCR among NCCN low-risk (HR, 2.16; P <.001) and intermediate-risk (hazard ratio [HR], 1.34; P = .024) classes and pathologic Gleason score ≤ 6 (HR, 2.42; P <.001) and Gleason score 7 (HR, 1.71; P <.001). BCR-free survival for very low-risk AA men was similar to low-risk white men (P = .890); BCR-free survival for low-risk AA men was similar to intermediate-risk white men (P = .060).

CONCLUSION

When stratified by NCCN risk, AA men with very low-, low-, or intermediate-risk prostate cancer who undergo RP are more likely to have adverse pathologic findings and BCR compared with white men. AA men with "low risk" prostate cancer, especially those considering active surveillance, should be counseled that their recurrence risks can resemble those of whites in higher risk categories.

African-American Men with Low-Risk Prostate Cancer: Modern Treatment and Outcome Trends

OBJECTIVE

To investigate the clinical characteristics and treatment patterns for African-American (AA) men with low-risk prostate cancer (PCa) using a national, population-based dataset.

METHODS

We conducted a retrospective review of the Surveillance Epidemiology and End Results database 2004-2008. AA men aged ≥40 years with low-risk PCa were identified. For comparison, white men were selected using the same selection criteria. We reviewed all recorded treatment modalities. Definitive treatment (DT) was defined as undergoing radiotherapy or prostatectomy.

RESULTS

Overall, 7246 AA men and 47,154 white men met the criteria. Most of the patients had PSA level between 4.1 and 6.9 ng/mL (56.2 %) and received DT (76 %). Black men were younger (mean age: 62(±8) vs. 65(±10) years), less likely to receive DT (adjusted odds ratio (AOR), 0.71 [0.67-0.76]), and of those receiving DT, less likely to undergo prostatectomy (AOR, 0.58 [0.54-0.62]). Patients receiving DT had lower crude cancer-specific and overall mortality (0.17 vs. 0.41 % and 2.9 vs. 7.8 %, p value < 0.001, respectively, among blacks). The difference in overall mortality was largest among ≥ 75 years (5.6 vs. 18.2 %). Across age groups, blacks had higher all-cause mortality (AOR, 1.45 [1.13-1.87] and 1.56[1.31-1.86] for <65 and ≥ 65 years, respectively).

CONCLUSION

Our study of a large modern cohort of men with low-risk PCa demonstrates significant lower receipt of DT, lower receipt of prostatectomy among those receiving DT, and lower survival for black men compared to their white counterparts. Older men were less likely to receive DT. Patients who received DT had better survival. The survival difference was most striking among the elderly.

The association between race and prostate cancer risk on initial biopsy in an equal access, multiethnic cohort

PURPOSE

Population-based studies have established a link between race and prostate cancer (PC) risk, but whether race predicts PC after adjusting for clinical characteristics is unclear. We investigated the association between race and risk of low- and high-grade PC in men undergoing initial prostate biopsy in an equal access medical center.

METHODS

We conducted a retrospective record review of 887 men (48.6 % black, 51.4 % white) from the Durham Veterans Affairs Medical Center who underwent initial prostate biopsy between 2001 and 2009. Multivariable logistic regression analysis of race and biopsy outcome was conducted adjusting for age, body mass index, number of cores taken, prostate-specific antigen (PSA), and digital rectal examination findings. Multinomial logistic regression was used to test the association between black race and PC grade (Gleason <7 vs. ≥7).

RESULTS

Black men were younger at biopsy (61 vs. 65 years, p < 0.001) and had a higher pre-biopsy PSA (6.6 vs. 5.8 ng/ml, p = 0.001). A total of 499 men had PC on biopsy (245 low grade; 254 high grade). In multivariable analyses, black race was significantly predictive of PC overall [odds ratio 1.50, p = 0.006] and high-grade PC [relative risk ratio (RRR) 1.84, p = 0.001], but was not significantly associated with low-grade PC (RRR 1.29, p = 0.139).

CONCLUSION

In an equal access healthcare facility, black race was associated with greater risk of PC detection on initial biopsy and of high-grade PC after adjusting for clinical characteristics. Additional investigation of mechanisms linking black race and PC risk and PC aggressiveness is needed.

Evidence for molecular differences in prostate cancer between African American and Caucasian men

PURPOSE

The aim of this study was to compare the frequency of ERG rearrangement, PTEN deletion, SPINK1 overexpression, and SPOP mutation in prostate cancer in African American and Caucasian men.

EXPERIMENTAL DESIGN

Dominant tumor nodules from radical prostatectomy specimens of 105 African American men (AAM) were compared with 113 dominant nodules from Caucasian men (CaM). Clinical and pathologic characteristics of the two groups were similar. SPINK1 overexpression was evaluated by immunohistochemistry, ERG rearrangement and PTEN deletion by FISH, and SPOP mutation by Sanger sequencing.

RESULTS

ERG rearrangement was identified in 48 of 113 tumors (42.5%) in CaM and 29 of 105 tumors (27.6%) in AAM (P = 0.024). PTEN deletion was seen in 19 of 96 tumors (19.8%) in CaM and 7 of 101 tumors (6.9%) in AAM (P = 0.011). SPINK1 overexpression was present in 9 of 110 tumors (8.2%) in CaM and 25 of 105 tumors (23.4%) in AAM (P = 0.002). SPOP mutation was identified in 8 of 78 (10.3%) tumors in CaM and 4 of 88 (4.5%) tumors in AAM (P = 0.230). When adjusted for age, body mass index, Gleason score, and pathologic stage, ERG rearrangement and SPINK1 overexpression remain significantly different (P = 0.018 and P = 0.008, respectively), and differences in PTEN deletion and SPOP mutation approach significance (P = 0.061 and P = 0.087, respectively).

CONCLUSIONS

Significant molecular differences exist between prostate cancers in AAM and CaM. SPINK1 overexpression, an alteration associated with more aggressive prostate cancers, was more frequent in AAM, whereas ERG rearrangement and PTEN deletion were less frequent in this cohort. Further investigation is warranted to determine whether these molecular differences explain some of the disparity in incidence and mortality between these two ethnic groups.

Circumcision and prostate cancer: a population-based case-control study in Montréal, Canada

Objectives

To investigate the possible association between circumcision and prostate cancer risk, to examine whether age at circumcision influences prostate cancer risk, and to determine whether race modifies the circumcision–prostate cancer relationship.

Subjects and Methods

PROtEuS (Prostate Cancer and Environment Study), a population-based case-control study set amongst the mainly French-speaking population in Montréal, Canada, was used to address study objectives. The study included 1590 pathologically confirmed prostate cancer cases diagnosed in a Montréal French hospital between 2005 and 2009, and 1618 population controls ascertained from the French electoral list, frequency-matched to cases by age. In-person interviews elicited information on sociodemographic, lifestyle and environmental factors. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) between circumcision, age at circumcision and prostate cancer risk, adjusting for age, ancestry, family history of prostate cancer, prostate cancer screening history, education, and history of sexually transmitted infections.

Results

Circumcised men had a slightly lower risk, albeit not statistically significant, of developing prostate cancer than uncircumcised men (OR 0.89, 95% CI 0.76–1.04). Circumcision was found to be protective in men circumcised aged ≥36 years (OR 0.55, 95% CI 0.30–0.98). A weaker protective effect was seen among men circumcised within 1 year of birth (OR 0.86, 95% CI 0.72–1.04). The strongest protective effect of circumcision was recorded in Black men (OR 0.40, 95% CI 0.19–0.86, P-value for interaction 0.02) but no association was found with other ancestral groups.

Conclusion

Our findings provide novel evidence for a protective effect of circumcision against prostate cancer development, especially in those circumcised aged ≥36 years; although circumcision before the age of 1 year may also confer protection. Circumcision appeared to be protective only among Black men, a group that has the highest rate of disease. Further research into the differences in effect of circumcision on prostate cancer risk by ancestry is warranted, as is the influence of age at circumcision.

Correlation between beta1 integrin expression and prognosis in clinically localized prostate cancer

Integrins are transmembrane glycoprotein receptors that regulate cell-matrix interactions, thus functioning as sensors from the environment. They also act as cell adhesion molecules that are responsible for the maintenance of the normal epithelial phenotype. Some studies have reported a correlation between carcinogenesis and changes in integrin expression, especially β1 integrin, however its role in prostate cancer (PC) is unclear. The aim of our study was to evaluate the expression of β1 integrin in localized PC and to correlate the pattern of expression with recurrence after surgical treatment. Methods For this case-control study, we retrospectively selected surgical specimens from 111 patients with localized PC who underwent radical prostatectomy. Recurrence was defined as a PSA level exceeding 0.2 ng/mL after surgery, and the median follow-up was 123 months. Integrin expression was evaluated by immunohistochemistry in a tissue microarray containing two samples from each tumor. We employed a semiquantitative analysis and considered a case as positive when the expression was strong and diffusely present.

RESULTS

There was a loss of 11 cases during the tissue micro array assembling. β1 expression was positive in 79 of the 100 evaluated cases (79%). The univariate and multivariate analyses showed that the negative expression of β1 integrin was associated with biochemical recurrence (p = 0.047) and time to recurrence after radical prostatectomy (p = 0.023). When β1 was negative, the odds ratio for recurrence was 2.78 times higher than that observed in the positive cases [OR = 2.78, p = 0.047, IC 95% (1.01-7.66)].

CONCLUSIONS

The loss of β1 integrin immune expression was correlated with biochemical recurrence in patients treated with radical prostatectomy for localized PC.

'Race' and prostate cancer mortality in equal-access healthcare systems

BACKGROUND

Reports suggest worse health-related outcomes among black (vs white) men diagnosed with prostate cancer, but appropriate cause-effect inferences are complicated by the relationship of race and other prognostic factors.

METHODS

We searched the literature to find contemporary articles focusing on mortality among black and white men with prostate cancer in equal-access healthcare systems. We also directly assessed the association of race and prostate cancer mortality by conducting an observational cohort analysis of 1270 veterans diagnosed with prostate cancer and followed for 11 to 16 years at 9 medical centers within the Veterans Health Administration.

RESULTS

Among 5 reports providing quantitative results for the association of race and mortality among men with prostate cancer in equal-access systems, outcomes were similar for black and white men. Race also was not a prognostic factor in the observational cohort analysis of US veterans, with an adjusted hazard ratio for black (vs white) men and prostate cancer mortality of 0.90 (95% confidence interval, 0.58-1.40; P = .65).

CONCLUSIONS

Mortality among black and white patients with prostate cancer is similar in equal-access healthcare systems. Studies that find racial differences in mortality (including cause-specific mortality) among men with prostate cancer may not account fully for socioeconomic and clinical factors.

Platelet-derived growth factor-BB accelerates prostate cancer growth by promoting the proliferation of mesenchymal stem cells

Mesenchymal stem cells (MSCs) favor cancer growth by facilitating immunosuppression status in tumor microenvironment. However, the function and mechanism of MSCs in initiating and developing prostate cancer remains to be fully understood. In this study, we first found that MSCs promoted prostate cancer (PCa) tumor growth in vivo and cell proliferation in vitro by using PCs cell strain RM-1. Both exogenous and endogenous MSCs could be recruited into the tumor microenvironment by using bone-marrow transplantation model. We further demonstrated that PDGF-BB produced by RM-1 cell promoted MSCs proliferation in vivo and in vitro, which was abrogated by Si-RNA specific to PDGF-BB. And inflammatory cytokines, such as interferon gamma, tumor necrosis factor alpha, and anti-inflammatory cytokine transformation growth factor alpha, further increased the ability of RM-1 to produce PDGF-BB. Overall, PCa cells produced PDGF-BB favors the proliferation of MSCs, which may elicit immunosuppressive function and enable PCa cells to escape from the immunity surveillance in tumor inflammatory microenvironment.

Sociodemographic disparities in the treatment of small renal masses

OBJECTIVE

To examine the presence of specific sociodemographic disparities in the treatment of individuals with small renal masses.

PATIENTS AND METHODS

Patients diagnosed with pT1aN0M0 renal cell carcinoma (RCC) were identified from the Surveillance, Epidemiology, and End Results database (years 1988-2008). Treatment type was stratified into non-surgical and surgical management and the group of patients who underwent surgical intervention was further stratified into those who underwent partial nephrectomy (PN) and those who underwent radical nephrectomy (RN). The main variables of interest were race and gender, as well as family income and poverty and education levels. Temporal trend analyses and logistic regression models were performed.

RESULTS

Of 26,468 patients with T1aN0M0 RCC, 2797 (10.6%) were non-surgically managed and 23,671 (89.4%) underwent surgery. Of the latter, 14,705 (62.1%) underwent RN and 8966 (37.9%) PN. In multivariable analyses, black patients were 23% more likely to be non-surgically managed than other ethnic groups, and if surgically managed, were 20% less likely to undergo PN (both P ≤ 0.007). Men were 19% more likely than women to be non-surgically managed, but remained 14% more likely to receive a PN (both P < 0.001). Treatment disparities according to income, education and poverty level were recorded. Poverty (odds ratio [OR]: 1.002) and education (OR: 0.998) proxies emerged as important determinants of non-surgical management, whereas income (OR: 1.08, all P ≤ 0.02) was a determinant of PN.

CONCLUSIONS

Social inequalities regarding access to treatment remain prevalent among patients diagnosed with small renal masses. The persistence of such a phenomenon is a concerning trend which merits further investigation.

Genetic and molecular differences in prostate carcinogenesis between African American and Caucasian American men

Prostate cancer is the most common non-skin cancer and the second leading cause of cancer-related death for men in the United States. Prostate cancer incidence and associated mortality are highest in African American men in comparison to other races. The observed differences in incidence and disease aggressiveness at presentation support a potential role for different pathways of prostate carcinogenesis between African American and Caucasian men. This review focuses on some of the recent molecular biology discoveries, which have been investigated in prostate carcinogenesis and their likely contribution to the known discrepancies across race and ethnicity. Key discussion points include the androgen receptor gene structure and function, genome-wide association studies and epigenetics. The new observations of the ethnic differences of the ERG oncogene, the most common prostate cancer gene, are providing new insights into ERG based stratification of prostate cancers in the context of ethnically diverse patient populations. This rapidly advancing knowledge has the likely potential to benefit clinical practice. Current and future work will improve the ability to sub-type prostate cancers by molecular alterations and lead to targeted therapy against this common malignancy.

High incidence of prostate cancer metastasis in Afro-Brazilian men with low educational levels: a retrospective observational study

BACKGROUND

This study investigated factors related to ethnicity and educational level, their correlation with tumor stage at the time of diagnosis, and their influence on treatment outcomes in patients with prostate cancer.

METHODS

In this retrospective observational study, we analyzed the medical records of 1,349 male patients treated for prostatic adenocarcinoma. We collected information about sociodemographic variables, including educational level and self-reported skin color. We also classified the disease according whether it was to more likely to present with metastasis and measured the tumor response to treatment.

RESULTS

Less-educated (<8 years of education) individuals were 4.8 times more likely to develop metastasis than those with more education (>11 years of education; p < 0.001). Similarly, patients with a self-reported black skin color had a 300% increased risk of metastasis at diagnosis (p = 0.001). Distant metastasis was independently correlated with worse outcomes, such that individuals with distant metastasis were 10 times more likely to die than were those without distant metastasis.

CONCLUSIONS

Patients with self-reported black skin color and <8 years of education were more likely to display advanced disease at the time of diagnosis compared with their counterparts. Only the presence of metastasis was independently associated with mortality or progressive disease.

Elevated polycyclic aromatic hydrocarbon-DNA adducts in benign prostate and risk of prostate cancer in African Americans

Carcinogen-DNA adducts, a marker of DNA damage, are capable of inducing mutations in oncogenes and tumor suppressor genes, resulting in carcinogenesis. We have shown previously that polycyclic aromatic hydrocarbon (PAH)-DNA adduct levels in prostate cancer cases vary by cellular histology and that higher adduct levels are associated with biochemical recurrence. A nested case-control study was conducted in a historical cohort of 6692 men with histopathologically benign prostate specimens. PAH-DNA adduct levels were determined by immunohistochemistry in benign prostate specimens from 536 prostate cancer case-control pairs (59% White and 41% African American). We estimated the overall and race-stratified risk of subsequent prostate cancer associated with higher adduct levels. Prostate cancer risk for men with elevated adduct levels (defined as greater than control group median) was slightly increased [odds ratio (OR) = 1.28, 95% confidence interval (CI) = 0.98-1.67, P = 0.07]. After race stratification, elevated adduct levels were significantly associated with increased risk in African American men (OR = 1.56, CI = 1.00-2.44, *P = 0.05) but not White men (OR = 1.14, CI = 0.82-1.59, P = 0.45). Elevated PAH-DNA adduct levels were significantly associated with 60% increased risk of prostate cancer among cases diagnosed 1-4 years after cohort entry (OR = 1.60, CI = 1.07-2.41) with a greater risk observed in African Americans within the first 4 years of follow-up (OR = 4.71, CI = 1.97-11.26, ***P = 0.0005). Analyses stratified by age or tumor grade revealed no additional significant heterogeneity in risk. Increased prostate cancer risk associated with high PAH-DNA adduct levels in benign prostate was found only in African Americans; risk was greatest within 4 years of follow-up, possibly reflecting a carcinogenic process not yet histologically detectable.