Racial Disparities In Prostate Cancer Research Articles

The association of prostatic lipids with progression, racial disparity and discovery of biomarkers in prostate cancer

BackgroundIt remains under-investigated whether prostatic lipid profiles are associated with pathogenesis, progression, racial disparity, and discovery of biomarkers in prostate cancer (PCa). MethodsThe electrospray ionization-tandem mass spectrometry was applied to quantitate prostatic lipids in human and mouse PCa and non-cancer prostatic tissues. Biostatistics and bioinformatics were used to compare the concentrations of prostatic lipids at levels of total lipid, group, class and individual species between PCa and benign prostatic tissues, between races, and among pathological conditions of PCa. ResultsProstatic concentrations of total lipids as well as neutral lipids were significantly higher in PCa than in benign prostatic tissues in all population and Caucasian American population, but not in African American population. The prostatic phospholipid were not statistically different between PCa and benign prostatic tissues in all study populations. Cholesteryl ester is the only lipid class significantly higher in PCa than in benign prostatic tissues in all study populations. A panel of prostatic lipid parameters in each study population was identified as diagnostic and prognostic biomarkers with >60% of sensitivity, specificity and accuracy simultaneously. Lipid profiling on mouse prostatic tissues further confirmed correlation of prostatic lipid profiles to the pathogenesis and progression of PCa. In addition, a few prostatic lipids in mouse can serve as prognostic biomarkers in differentiation of indolent from aggressive PCa. ConclusionThe prostatic lipids are widely associated with the pathogenesis, progression and racial disparity of PCa. A panel of prostatic lipids can serve as diagnostic, prognostic and race-specific biomarkers for PCa.

Racial disparities in prostate cancer among black men: epidemiology and outcomes.

Prostate cancer has the widest racial disparities of any cancer, and these disparities appear at every stage of the cancer continuum. This review focuses on the disparities in prostate cancer between Black and White men, spanning from prevention and screening to clinical outcomes. We conduct an expansive review of the literature on racial disparities in prostate cancer, interpret the findings, and discuss areas of unmet need in research. We provide an overview of epidemiologic concepts necessary to understanding the current state of prostate cancer disparities, discuss the complexities of studying race, and review potential drivers of disparities in incidence and mortality. We argue that the cause of this disparity is multifactorial and due to a combination of social and environmental factors. The path forward needs to focus on enrolling and retaining Black men in prostate cancer clinical trials and observational studies and identifying potential interventions to improve prevention and clinical outcomes in Black men.

Examining the Racial Disparities in Prostate Cancer

Currently, Black men in the United States are greater than 1.5 times as likely to be diagnosed with prostate cancer and more than twice as likely to succumb to the disease. While racial disparities in prostate cancer have been well documented, we must analyze these disparities in the correct context. Discussion of these disparities without correctly describing race as a social construct and acknowledging the impact of structural racism is insufficient. This article reviews the disparities seen in screening, treatment, outcomes, and clinical trial participation. We conclude by outlining future steps to help understand and study disparities, as we strive toward equitable outcomes.

Progression on active surveillance for prostate cancer in Black men: a systematic review and meta-analysis.

Several studies evaluated prostate cancer (PCa) outcomes in Black men on active surveillance (AS); most studies contained few Black men and results were conflicting. We performed a systematic review and meta-analyze of race and outcomes on AS. A systematic search was performed for articles of men with Grade Group 1 or 2 (GG1 or GG2) PCa on AS. All studies required race-specific comparative progression data. Progression to treatment, PSA, or biopsy progression were considered and relative risk (RR) estimates of Black men progressing were extracted and pooled using random-effects models. Differences by study-level characteristics were evaluated using subgroup and a cumulative meta-analysis by time. In total, 12 studies were included (3137 Black and 12,206 non-Black men); eight prospective (27%, n = 4210) and four retrospectives (73%, n = 11,133) cohorts. The overall RR of progression for Black men was 1.62 (95%CI, 1.21-2.17), I2 = 64% (95% CI, 32-80%), (χ2 = 30.23; P = 0.001; τ2 = 0.16). Black men with GG1 PCa alone had a higher pooled progression: RR = 1.81 (95% CI, 1.23-2.68). Including only studies with clinical progression (excluding progression to treatment), potentiated results: RR = 1.82 (95%CI, 1.27-2.60). However, a cumulative meta-analysis demonstrated decreasing pooled effect over time, with contemporary studies after 2019 showing a tempered effect (RR: 1.29, 95% CI: 1.20-1.39). Many studies attribute racial disparity in PCa to delayed presentation of disease, however, AS is unique since all AS eligible men have a low grade and stage PCa. Our findings suggest Black men may have an increased risk of progression during AS, but the association is not so strong that Black men should be discouraged from undergoing AS. Indeed, contemporary evidence suggests stricter inclusion, better confirmatory testing or better access to care may temper these findings. Importantly, these results utilize self-reported race, a social construct that has many limitations.

A deep imputation and inference framework for estimating personalized and race-specific causal effects of genomic alterations on PSA.

Prostate Specific Antigen (PSA) level in the serum is one of the most widely used markers in monitoring prostate cancer (PCa) progression, treatment response, and disease relapse. Although significant efforts have been taken to analyze various socioeconomic and cultural factors that contribute to the racial disparities in PCa, limited research has been performed to quantitatively understand how and to what extent molecular alterations may impact differential PSA levels present at varied tumor status between African-American and European-American men. Moreover, missing values among patients add another layer of difficulty in precisely inferring their outcomes. In light of these issues, we propose a data-driven, deep learning-based imputation and inference framework (DIIF). DIIF seamlessly encapsulates two modules: an imputation module driven by a regularized deep autoencoder for imputing critical missing information and an inference module in which two deep variational autoencoders are coupled with a graphical inference model to quantify the personalized and race-specific causal effects. Large-scale empirical studies on the independent sub-cohorts of The Cancer Genome Atlas (TCGA) PCa patients demonstrate the effectiveness of DIIF. We further found that somatic mutations in TP53, ATM, PTEN, FOXA1, and PIK3CA are statistically significant genomic factors that may explain the racial disparities in different PCa features characterized by PSA.

Abstract 782: Exploring the contribution of introgressed ancient DNA to prostate cancer racial disparity

Abstract Introduction: Prostate cancer is the most common cancer in men and there is racial disparity in prostate cancer incidence and mortality globally, with greater disease burden in men of African ancestry, followed by European ancestry and least in men of Asian ancestry. The etiology of prostate cancer is not fully understood, but includes genetic and environmental factors. Present day non-Africans are reported to have introgressed DNA from Neanderthal and Denisovan ancestors. Over 170 prostate cancer associated single nucleotide polymorphisms (SNPs) have been identified from several genome-wide association studies (GWAS), with SNPS on chromosomes 2, 8 and 22 reported as showing variation between African and non-African men with prostate cancer. We performed analysis of prostate cancer associated SNPs on chromosomes 2, 8 and 22 to determine if DNA introgression could explain the racial variation. Methods: We obtained data on prostate cancer associated SNPs from the GWAS catalog (https://www.ebi.ac.uk/gwas) and from reports that were not included in the catalog. Using an Ancient Genome Browser provided by the Max Plank Institute (https://www.eva.mpg.de/genetics/genomeprojects/neandertal/index.html), we determined whether SNPs on chromosomes 2, 8 and 22 were present in African, Neanderthal or Denisovan genomes. Based on the results, we inferred that SNPs were introgressed if they were present in Neanderthal or Denisovan genomes but absent from African genomes. Results: 49, 59 and 17 prostate cancer SNPs were reported in chromosomes 2, 8 and 22 respectively. 23/49 in ch2, 25/59 in ch8 and 9/17 in ch22 were present in Neanderthal and or Denisovan genomes. SNPs in ch2 (rs13403657, rs12621278) and ch8 (rs7825414) were present in Neanderthal or Denisovan genomes but absent in African genomes. These SNPs lie in regions that have previously been reported to harbor introgressed DNA. Conclusion: Our analyses identified prostate cancer associated SNPs that are likely to have been introgressed into present day non-Africans by extinct Neanderthal and Denisovan ancestors. Phenotypic changes caused by introgressed DNA could be contributing to racial disparities in prostate cancer in present day humans. Citation Format: Evi O. Useh, Suresh Venugopal, Chidi N. Molokwu. Exploring the contribution of introgressed ancient DNA to prostate cancer racial disparity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 782.

Abstract 778: CD24 mutant p53 contribute to racial disparities in prostate cancer

Abstract African-American (AA) men have the highest rate of prostate cancer among racial or ethnic groups. CD24, a cell-surface protein anchored by glycosyl-phosphatidyl-inositol (GPI), often is over-expressed in cancers and serves as a marker for poor prognosis of human cancer, including prostate cancer. Using a functional analysis of prostate cancer cells, we found a CD24-dependent inactivation of mutant p53, but the clinical significance of this observation remained uncertain. Here, we validated these results with samples of human prostate cancer and explored the role of a CD24-p53 axis in racial disparities of prostate cancer. Our bioinformatics analysis of public datasets, including TCGA data, confirmed higher levels of CD24 mRNA expression in late-stage and metastatic prostate cancer. In the present study, we addressed the association of CD24 with mutant p53 and their differential expression between AA and European-American (EA) prostate cancers and assessed whether cells with CD24 and mutant p53 contribute to health disparities in prostate cancer. CD24, mutant p53, MDM2, and ARF proteins were expressed in 55%, 24%, 39%, and 68% of prostate cancer samples, respectively. CD24 and mutant p53 were present more frequently in late-stage and metastatic prostate cancer. The presence of CD24 was associated with a > 4-fold risk of metastasis, which included lymph node and distant metastases. H-score analysis showed positive correlations of CD24 expression with mutant p53 and MDM2. A racial disparity was evident for CD24 but not for mutant p53. In 32 CD24+/mutant p53+ cases, a TP53R273H mutation was found in five cases, but no TP53R175H mutation was found. The CD24-p53 axis may contribute to aggressive and metastatic prostate cancers, especially those of AAs. Citation Format: Xuelian Cui, Shuaibin Wang, Lizhong Wang. CD24 mutant p53 contribute to racial disparities in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 778.

Abstract 2529: Specific racial CYP2R1 correlation with circadian rhythm genes in prostate adenocarcinoma

Abstract Introduction: Vitamin D in its hormonal form, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) binds to the vitamin D receptor (VDR) to regulate genes, for example, in skeletal mineralization. However, it also has other potent biological functions in regulating apoptosis, proliferation, and inflammation. In carcinogenesis, 1,25(OH)2D3 may be exploited to regulate these crucial pathways. It is also clear that a frequent cancer disparity exists amongst African American (AA) men with prostate cancer compared to European Americans (EA). AA men show a higher incidence rate and two to three times increased risk of mortality than EA counterparts. Various groups have suggested that 1,25(OH)2D3 levels and/or VDR functions are risk factors linked with increased prostate cancer incidence in AA men. Incidentally, reports showed that VD plays a crucial role in regulating circadian rhythm (CR). There is, therefore, a need to understand and evaluate 1,25(OH)2D3-dependent CR regulation and the association with racial disparity in prostate cancer. This study aimed to determine if there are differentially expressed VD metabolic enzymes in AA and EA and evaluate if the differential expression correlates with CR genes. Methods: The Cancer Genome Atlas Research Network (TCGA), 2015 database was queried for expression of VD metabolizing enzymes and CR genes. The search was carried out on prostate adenocarcinoma expressions of AA and EA. VD metabolizing enzymes queried are CYP2R1, CYP24A1, CYP27B1, CYP27A1, while CR genes queried include ARNTL, CLOCK, CRY1, CRY2, CSNK1E, NPAS2, PER1, PER2, PER3, and TIMELESS. Prostate adenocarcinoma racial differential expressions of AA and EA were evaluated, and a correlation study was done using the Pearson correlation. Results: VD metabolic enzyme, CYP2R1, and CR gene, ARNTL were significantly upregulated in AA compared to EA counterparts. Although CYPR1 correlates negatively with CLOCK, CRY2, and PER3 in both races, CYPR1 specifically showed a positive correlation with CR gene CRY1 in EA and negative correlations with CR genes NPAS2 and CSNK1E in AA. However, a significant correlation between CYP2R1 and ARNTL in EA and AA was not observed. Conclusion: The data suggest a relationship between racial influence and prostate cancer associated with VD metabolism and CR regulation. Hence, it is crucial to elucidate CYP2R1 regulation in prostate cancer related to VD levels and CR regulation, especially with a focus on racial disparities. Citation Format: Isaacson Bababode Adelani, Solomon Oladapo Rotimi, Clayton Yates, Moray Campbell. Specific racial CYP2R1 correlation with circadian rhythm genes in prostate adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2529.

Quality of YouTube Videos on Prostate Cancer Screening for Black Men.

Black men are disproportionately impacted by prostate cancer. Guidelines agree that Black men should make informed decisions about whether to engage in prostate cancer screening. YouTube is widely used among Black men and impacts understanding of health conditions. Given that misleading online health information might be especially harmful to Black men, the objective of this study was to evaluate the quality of information regarding prostate cancer screening for Black men available on YouTube. Four viewers watched the top 50 videos using the search term "Prostate Cancer Screening in Black Men." Videos were scored using the previously validated DISCERN quality criteria for consumer health information and the Patient Education Materials Assessment Tool (PEMAT). Results were compared based on video characteristics like presenter perceived demographics and viewer engagement metrics. Inter-rater reliability testing showed consistency for the PEMAT (interclass correlation coefficient [ICC] = 0.69) and DISCERN (ICC= 0.85). Few videos (16%) met the DISCERN quality threshold (54.4/80), and 28% of videos met the PEMAT threshold (10.5/15). Less than half of videos addressed racial disparities in prostate cancer. There was no difference in quality based on perceived race of the presenter (DISCERN P = .06, PEMAT P = .43). The overall quality of videos about prostate cancer screening in Black men is poor, including those with Black presenters. Clinicians should be aware of potential misinformation that Black patients receive from YouTube and the opportunity to improve the quality of available information about prostate cancer screening in Black men.

Using Genomics to Address Racial Disparities in Prostate Cancer

Using Genomics to Address Racial Disparities in Prostate Cancer

Comparative analysis of 1152 African-American and European-American men with prostate cancer identifies distinct genomic and immunological differences

Racial disparities in prostate cancer have not been well characterized on a genomic level. Here we show the results of a multi-institutional retrospective analysis of 1,152 patients (596 African-American men (AAM) and 556 European-American men (EAM)) who underwent radical prostatectomy. Comparative analyses between the race groups were conducted at the clinical, genomic, pathway, molecular subtype, and prognostic levels. The EAM group had increased ERG (P < 0.001) and ETS (P = 0.02) expression, decreased SPINK1 expression (P < 0.001), and basal-like (P < 0.001) molecular subtypes. After adjusting for confounders, the AAM group was associated with higher expression of CRYBB2, GSTM3, and inflammation genes (IL33, IFNG, CCL4, CD3, ICOSLG), and lower expression of mismatch repair genes (MSH2, MSH6) (p < 0.001 for all). At the pathway level, the AAM group had higher expression of genes sets related to the immune response, apoptosis, hypoxia, and reactive oxygen species. EAM group was associated with higher levels of fatty acid metabolism, DNA repair, and WNT/beta-catenin signaling. Based on cell lines data, AAM were predicted to have higher potential response to DNA damage. In conclusion, biological characteristics of prostate tumor were substantially different in AAM when compared to EAM.

Differences in Toxicity and Outcomes in Clinical Trial Participants From Minority Populations.

Black men have a higher prevalence of and mortality rate from prostate cancer compared with White men and have been shown to present with more aggressive and later-stage disease. How prostate cancer treatment affects these racial disparities is still unclear. Several studies have shown that Black men who receive treatment have a more pronounced decrease in prostate cancer-specific death; however, there remains a large disparity in all-cause mortality. This disparity may be in part related to a higher risk of death resulting from comorbidities, given the higher rates of cardiovascular disease and diabetes in Black men, both of which are complicated by the use of androgen-deprivation therapy. To further understand these disparities, it is important that we analyze the racial differences in adverse event rates and severity. Increasing the percentage of Black men in clinical trials will improve the understanding of the biologic drivers of racial disparities in prostate cancer. To evaluate the potential differences in adverse event reporting and demonstrate the feasibility of enrolling equal numbers of Black and White men in trials, we performed a prospective, multicenter study of abiraterone plus prednisone with androgen-deprivation therapy in men with metastatic castration-resistant prostate cancer, stratified by race. Racial differences in prostate-specific antigen kinetics and toxicity profile were demonstrated. Higher rates and severity of adverse events related to adrenal hormone suppression, including hypertension, hypokalemia, and hypomagnesemia, were seen in the Black cohort, not previously reported. Increased enrollment of Black men in prostate cancer clinical trials is imperative to further understand the impact of race on clinical outcomes and treatment tolerability.

Racial differences in the treatment and outcomes for prostate cancer in Massachusetts.

Massachusetts is a northeastern state with universally mandated health insurance since 2006. Although Black men have generally worse prostate cancer outcomes, emerging data suggest that they may experience equivalent outcomes within a fully insured system. In this setting, the authors analyzed treatments and outcomes of non-Hispanic White and Black men in Massachusetts. White and Black men who were 20 years old or older and had been diagnosed with localized intermediate- or high-risk nonmetastatic prostate cancer in 2004-2015 were identified in the Massachusetts Cancer Registry. Adjusted logistic regression models were used to assess predictors of definitive therapy. Adjusted and unadjusted survival models compared cancer-specific mortality. Interaction terms were then used to assess whether the effect of race varied between counties. A total of 20,856 men were identified. Of these, 19,287 (92.5%) were White. There were significant county-level differences in the odds of receiving definitive therapy and survival. Survival was worse for those with high-risk cancer (adjusted hazard ratio [HR], 1.50; 95% CI, 1.4-1.60) and those with public insurance (adjusted HR for Medicaid, 1.69; 95% CI, 1.38-2.07; adjusted HR for Medicare, 1.2; 95% CI, 1.14-1.35). Black men were less likely to receive definitive therapy (adjusted odds ratio, 0.78; 95% CI, 0.74-0.83) but had a 17% lower cancer-specific mortality (adjusted HR, 0.83; 95% CI, 0.7-0.99). Despite lower odds of definitive treatment, Black men experience decreased cancer-specific mortality in comparison with White men in Massachusetts. These data support the growing body of research showing that Black men may achieve outcomes equivalent to or even better than those of White men within the context of a well-insured population. There is a growing body of evidence showing that the excess risk of death among Black men with prostate cancer may be caused by disparities in access to care, with few or no disparities seen in universally insured health systems such as the Veterans Affairs and US Military Health System. Therefore, the authors sought to assess racial disparities in prostate cancer in Massachusetts, which was the earliest US state to mandate universal insurance coverage (in 2006). Despite lower odds of definitive treatment, Black men with prostate cancer experience reduced cancer-specific mortality in comparison with White men in Massachusetts. These data support the growing body of research showing that Black men may achieve outcomes equivalent to or even better than those of White men within the context of a well-insured population.

Race reporting and diversity in US food and drug administration (FDA) registration trials for prostate cancer; 2006\u20132020

BackgroundThere is significant racial disparity in prostate cancer (PCa) in terms of incidence, treatment, and outcomes. Racial diversity and compliance with FDA race reporting guidelines in PCa drug registration trials are unknown. We analyzed racial diversity and race reporting in drug licensing trials for PCa.MethodsNew drug authorizations for PCa from 2006 to 2020 were identified. The corresponding licensing trial publications were analyzed to check compliance with current FDA recommendations for race reporting. If race was unreported, the clinical trial report was analyzed to determine participant recruitment by race and lead the recruiting country.ResultsDuring the study period, 17 new drug registrations for the management of PCa involving ten unique drugs were identified. In total, 18,455 participants were included in FDA registration trials, of which 76.3% were white or Caucasian, 7.9% Asian, 2.9% Black or African American, 0.5% American Indian or Alaskan Native, 0.1% Native Hawaiian or other Pacific Islander, 1.8% other or multiple races and 10.5% unknown. 53% of trials reported race in the licensing publication, however of this only 55% met current FDA recommendations. When the race was unreported in the licensing publication, 88% of studies had further information in the clinical study report.ConclusionWe found a significant under-representation of non-white participants in FDA drug registration trials for PCa. Race reporting in licensing publication is inconsistent and both FDA and International Committee of Medical Journal Editors guidelines are not being universally followed. Given the disproportionality of the disease burden of PCa, recruitment of Black and other minority participants to trials should be a research priority.

Susceptibility-Associated Genetic Variation in NEDD9 Contributes to Prostate Cancer Initiation and Progression.

Although American men of European ancestry represent the largest population of patients with prostate cancer, men of African ancestry are disproportionately affected by prostate cancer, with higher prevalence and worse outcomes. These racial disparities in prostate cancer are due to multiple factors, but variations in genomic susceptibility such as SNP may play an important role in determining cancer aggressiveness and treatment outcome. Using public databases, we have identified a prostate cancer susceptibility SNP at an intronic enhancer of the neural precursor expressed, developmentally downregulated 9 (NEDD9) gene, which is strongly associated with increased risk of patients with African ancestry. This genetic variation increased expression of NEDD9 by modulating the chromatin binding of certain transcription factors, including ERG and NANOG. Moreover, NEDD9 displayed oncogenic activity in prostate cancer cells, promoting prostate cancer tumor growth and metastasis in vitro and in vivo. Together, our study provides novel insights into the genetic mechanisms driving prostate cancer racial disparities. SIGNIFICANCE: A prostate cancer susceptibility genetic variation in NEDD9, which is strongly associated with the increased risk of patients with African ancestry, increases NEDD9 expression and promotes initiation and progression of prostate cancer.See related commentary by Mavura and Huang, p. 3764.

Understanding racial disparities in survival among U.S. veterans with localized high-risk prostate cancer, 2004-2019.

202 Background: Known racial disparities in prostate cancer outcomes between African-American (AA) and non-Hispanic White (W) men may be ameliorated in the Veterans Health Administration (VA), a large national equal-access health system. We examined factors contributing to racial disparities in mortality among men with high-risk localized prostate cancer diagnosed in the VA. Methods: In this retrospective cohort study, we used linked administrative, survey, and electronic health record data from the Veterans Health Administration (VA) Corporate Data Warehouse to identify AA and W Veterans who were diagnosed with high-risk localized PC, as defined by D’Amico criteria, between January 1, 2004 and December 31, 2013. Patients were followed through December 31, 2019. The primary outcome was all-cause mortality. We used hierarchical Cox regression models, sequentially adjusting for covariates related to social determinants of health (e.g. travel time, marital status), clinical factors at diagnosis (e.g. PSA, Gleason, comorbidity), diagnosing facility, and prostate cancer treatment and adherence to American Cancer Society survivorship care guidelines. Results: Among 21,338 Veterans receiving continuous VA-based care (median age at diagnosis 66 years [interquartile range [IQR] 61-74]), 7,472 (28.7%) were AA, 9,404 (44.1%) died, and median follow-up was 8.4 years (IQR 6.1-11.1). After adjusting for all covariates, AA Veterans (adjusted hazard ratio [aHR] 0.84, 95% confidence interval [CI] 0.83-0.91) had improved overall survival compared to W Veterans. This association persisted in all hierarchical regressions (see Table), was present in all pre-specified subgroups, and was strongest among Veterans living in rural domiciles (aHR 0.70, 95% CI 0.64-0.77). Conclusions: AA Veterans with high-risk localized prostate cancer had improved long-term survival compared to W Veterans, which stands in contrast to prior studies among non-Veterans. Equal access to care may improve racial disparities in prostate cancer, although future studies should clarify mechanisms of improved survival for AA Veterans with prostate cancer in order to provide insights for ameliorating outcome disparities in non-Veterans with prostate cancer. [Table: see text]

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

BackgroundAfrican Americans (AAs) in the United States are known to have a higher incidence and mortality for Prostate Cancer (PCa). The drivers of this epidemiological disparity are multifactorial, including socioeconomic factors leading to lifestyle and dietary issues, healthcare access problems, and potentially tumor biology.Recent findingsAlthough recent evidence suggests once access is equal, AA men have equal outcomes to Caucasian American (CA) men, differences in PCa incidence remain, and there is much to do to reverse disparities in mortality across the USA. A deeper understanding of these issues, both at the clinical and molecular level, can facilitate improved outcomes in the AA population. This review first discusses PCa oncogenesis in the context of its diverse hallmarks before benchmarking key molecular and genomic differences for PCa in AA men that have emerged in the recent literature. Studies have emphasized the importance of tumor microenvironment that contributes to both the unequal cancer burden and differences in clinical outcome between the races. Management of comorbidities like obesity, hypertension, and diabetes will provide an essential means of reducing prostate cancer incidence in AA men. Although requiring further AA specific research, several new treatment strategies such as immune checkpoint inhibitors used in combination PARP inhibitors and other emerging vaccines, including Sipuleucel‐T, have demonstrated some proven efficacy.ConclusionGenomic profiling to integrate clinical and genomic data for diagnosis, prognosis, and treatment will allow physicians to plan a “Precision Medicine” approach to AA men. There is a pressing need for further research for risk stratification, which may allow early identification of AA men with higher risk disease based on their unique clinical, genomic, and immunological profiles, which can then be mapped to appropriate clinical trials. Treatment options are outlined, with a concise description of recent work in AA specific populations, detailing several targeted therapies, including immunotherapy. Also, a summary of current clinical trials involving AA men is presented, and it is important that policies are adopted to ensure that AA men are actively recruited. Although it is encouraging that many of these explore the lifestyle and educational initiatives and therapeutic interventions, there is much still work to be done to reduce incidence and mortality in AA men and equalize current racial disparities.

Comparative Genomics Reveals Distinct Immune-oncologic Pathways in African American Men with Prostate Cancer.

The role of immune-oncologic mechanisms of racial disparities in prostate cancer remains understudied. Limited research exists to evaluate the molecular underpinnings of immune differences in African American men (AAM) and European American men (EAM) prostate tumor microenvironment (TME). A total of 1,173 radiation-naïve radical prostatectomy samples with whole transcriptome data from the Decipher GRID registry were used. Transcriptomic expressions of 1,260 immune-specific genes were selected to assess immune-oncologic differences between AAM and EAM prostate tumors. Race-specific differential expression of genes was assessed using a rank test, and intergene correlational matrix and gene set enrichment was used for pathway analysis. AAM prostate tumors have significant enrichment of major immune-oncologic pathways, including proinflammatory cytokines, IFNα, IFNγ, TNFα signaling, ILs, and epithelial-mesenchymal transition. AAM TME has higher total immune content score (ICSHIGH) compared with 0 (37.8% vs. 21.9%, P = 0.003). AAM tumors also have lower DNA damage repair and are genomically radiosensitive as compared with EAM. IFITM3 (IFN-inducible transmembrane protein 3) was one of the major proinflammatory genes overexpressed in AAM that predicted increased risk of biochemical recurrence selectively for AAM in both discovery [HRAAM = 2.30; 95% confidence interval (CI), 1.21-4.34; P = 0.01] and validation (HRAAM = 2.42; 95% CI, 1.52-3.86; P = 0.0001) but not in EAM. Prostate tumors of AAM manifest a unique immune repertoire and have significant enrichment of proinflammatory immune pathways that are associated with poorer outcomes. Observed immune-oncologic differences can aid in a genomically adaptive approach to treating prostate cancer in AAM.

Abstract PO-192: Exploring the contribution of introgressed ancient DNA to prostate cancer racial disparity

Abstract Introduction Prostate cancer is the most common cancer in men and there is racial disparity in prostate cancer incidence and mortality globally, with greater disease burden in men of African ancestry, followed by European ancestry and least in men of Asian ancestry. The etiology of prostate cancer is not fully understood but includes genetic and environmental factors. Present day non-Africans are reported to have introgressed DNA from Neanderthal and Denisovan ancestors. Over 170 prostate cancer associated single nucleotide polymorphisms (SNPs) have been identified from several genome-wide association studies (GWAS), with SNPS on chromosomes 2, 8 and 22 reported as showing variation between African and non-African men with prostate cancer. We performed analysis of prostate cancer associated SNPs on chromosomes 2, 8 and 22 to determine if DNA introgression could explain the racial variation. Methods We obtained data on prostate cancer associated SNPs from the GWAS catalog (https://www.ebi.ac.uk/gwas) and from reports that were not included in the catalog. Using an Ancient Genome Browser provided by the Max Plank Institute (https://www.eva.mpg.de/genetics/genome-projects/neandertal/index.html), we determined whether SNPs on chromosomes 2, 8 and 22 were present in African, Neanderthal or Denisovan genomes. Based on the results, we inferred that SNPs were introgressed if they were present in Neanderthal or Denisovan genomes but absent from African genomes. Results 49, 59 and 17 prostate cancer SNPs were reported in chromosomes 2, 8 and 22 respectively. 23/49 in ch2, 25/59 in c 8 and 9/17 in ch22 were present in in Neanderthal and or Denisovan genomes. SNPs in ch2 (rs13403657, rs12621278) and ch8 (rs7825414) were present in Neanderthal or Denisovan genomes but absent in African genomes. These SNPs lie in regions that have previously been reported to harbour introgressd DNA. Conclusion Our analyses identified prostate cancer associated SNPs that are likely to have been introgressed into present day non-Africans by extinct Neanderthal and Denisovan ancestors. Phenotypic changes caused by introgressed DNA could be contributing to racial disparities in prostate cancer in present day humans. Citation Format: Evi O. Useh, Suresh Venugopal, Chidi N. Molokwu. Exploring the contribution of introgressed ancient DNA to prostate cancer racial disparity [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-192.

Abstract PO-226: Localization of macrophages and neutrophils in the prostate tumor microenvironment and their association with prostate cancer racial disparities

Abstract African American (AA) men are two to three times more likely to die from prostate cancer (PCa) than European American (EA) men. This disparity may be due in part to socioeconomic status and discrepancies in access to quality care. Studies also suggest that differences in innate immune effector cells and function in the tumor microenvironment of AA men may promote PCa aggressiveness. Increased tumor- associated macrophages are associated with poorer outcomes and a high neutrophil- to-lymphocyte ratio is significantly associated with poorer survival in men with PCa. However, the prevalence of innate immune cells, their spatial localization, and their relationship to PCa racial disparities is largely unknown. We evaluated CD66ce+ neutrophils and CD68+ (pan), CD80+ (M1), and CD163+ (M2) macrophages using RNA in situ hybridization or immunohistochemistry on formalin-fixed paraffin-embedded whole tissue sections from prostate donor tissues with no cancer (n=4) and radical prostatectomy tissues from AA and EA men with low grade (Gleason ≤ 3+4) and higher grade (Gleason ≥ 4+3) PCa (n=38). Tissue microarray (TMA) sets containing radical prostatectomy tissues (n=932) or distant metastatic tissues obtained at autopsy (n=6) were also evaluated. Immune marker expression in TMAs was quantified using TMAJ and FrIDA software. CD66ce+ neutrophils were primarily localized to blood vessels in organ donor prostate specimens as well as normal appearing, non-inflamed regions of radical prostatectomy specimens. Increased CD66ce+ neutrophils were present in inflamed regions of benign tissues from both races. In analysis of TMAs, there was significantly increased CD66ce+ neutrophils in tissues from EA men compared to AA men (p &amp;lt; 0.0001). There was also increased CD66ce expression in cancer compared to benign tissue spots (p &amp;lt;0.01), in low grade compared to higher grade cancer (p &amp;lt; 0.0001), in cancer with PTEN loss versus intact PTEN (p &amp;lt; 0.0001), and in ERG positive versus ERG negative cancer (p = 0.0011). There was no association between CD66ce+ neutrophils and risk of metastasis or biochemical recurrence. CD68+ and CD163+ macrophages were abundant in organ donor specimens, while CD80 expression was minimal. Similar expression patterns were observed in benign regions of radical prostatectomy specimens. In analysis of TMAs, CD68, CD80 and CD163 were significantly increased in cancer compared to benign tissues (p &amp;lt; 0.0001). CD163 expression was comparable between races, while CD80 expression was significantly higher in benign tissues from AA men compared to EA men (p = 0.0004). CD68, CD80 and CD163 expression were all significantly increased in benign spots from ERG positive versus ERG negative cases. In conclusion, there is increased infiltration of innate immune cells in the prostate tumor microenvironment of both AA and EA men, however the composition of innate immune cell infiltration varies between races. Our future studies aim to determine the influence of innate immune effector cells on PCa aggressiveness and outcomes. Citation Format: Janielle P. Maynard, Jiayun Lu, Igor Vidal, Corinne E. Joshu, Angelo M. De Marzo, Karen S. Sfanos. Localization of macrophages and neutrophils in the prostate tumor microenvironment and their association with prostate cancer racial disparities [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-226.