Prostate Cancer Health Disparities Research Articles

Exploring health disparities in prostate cancer through circulating tumor DNA analysis.

1603 Background: African American men (AAM) suffer from the highest rates of prostate cancer in the world. In addition, AAM experience the highest rates of aggressive prostate cancer and prostate cancer-specific mortality of any ethnic group in the United States [1, 2]. The reasons behind the increased burden of prostate cancer poor outcomes in AAM remain unresolved. A large proportion of variation in prostate cancer mortality remains unexplained solely by epidemiologic risk factors. We investigated genomic differences between AAM and Caucasian men with metastatic castration resistant prostate cancer (mCRPC) utilizing circulating tumor DNA (ctDNA) analysis. Methods: AAM and Caucasian men with mCRPC were enrolled in this study. We collected and analyzed 88 plasma samples, including 66 from Caucasian and 22 from African American patients, with no significant age difference between the groups. The targeted sequencing libraries were prepared following the Agilent SureSelect XT HS2 target enrichment workflow coupled with the SureSelect custom prostate cancer panel (Agilent, Inc.). The final libraries were sequenced on an Illumina NextSeq 2000 to generate 150 bp paired-end reads. Results: A total of 88 men with mCRPC were enrolled. About 60% of African American patients exhibited organ metastasis at the time of diagnosis, while this proportion was 36% for Caucasian patients and they primarily reported metastasis during relapse. Analyzing 1824 variants in 138 genes meeting inclusion criteria, 281 significant mutations across 88 genes revealed racial differences. Notably, 29% of these variants were somatic. Approximately 60 cancer-related pathways, tissues, and diseases were identified from these datasets, encompassing 59 of our significant genes. Among these associated genes, the prevalence of significant variants, higher in AAM, exceeds that in Caucasians in 76% of cases. The top genes that have more contribution in considering pathways are shown (Table). Conclusions: Genomic variations were observed in ctDNA analysis between African American and Caucasian patients diagnosed with metastatic castration-resistant prostate cancer. Our findings highlight the potential inclusion of ctDNA analysis in the clinical assessment of these patients, offering valuable insights for informed therapeutic decision-making. The top genes with the most contribution to prostate-related pathways. [Table: see text]

The impact of telomere length on prostate cancer aggressiveness, genomic instability and health disparities

The telomere repetitive TTAGGG motif at the ends of chromosomes, serves to preserve genomic integrity and chromosomal stability. In turn, genomic instability is a hallmark of cancer—implicating telomere disturbance. Prostate cancer (PCa) shows significant ancestral disparities, with men of African ancestry at the greatest risk for aggressive disease and associated genomic instability. Yet, no study has explored the role of telomere length (TL) with respect to ancestrally driven PCa health disparities. Patient- and technically-matched tumour-blood whole genome sequencing data for 179 ancestrally defined treatment naïve PCa patients (117 African, 62 European), we assessed for TL (blood and tumour) associations. We found shortened tumour TL to be associated with aggressive PCa presentation and elevated genomic instabilities, including percentage of genome alteration and copy number gains, in men of African ancestry. For European patients, tumour TL showed significant associations with PCa driver genes PTEN, TP53, MSH2, SETBP1 and DDX11L1, while shorter blood TL (< 3200 base pairs) and tumour TL (< 2861 base pairs) were correlated with higher risk for biochemical recurrence. Concurring with previous studies linking TL to PCa diagnosis and/or prognosis, for the first time we correlated TL differences with patient ancestry with important implications for future treatments targeting telomere dysfunction.

Abstract 1292: ProTALKS: A community outreach project founded by a graduate of the CaRE2 Community Scientist Research Advocacy training program, Mrs. Lynn Jones-Turpin

Abstract ProTALKS was created and led by a community member committed to reducing prostate cancer health disparities. ProTALKS stands for Prostate Cancer Outreach, Opinions, and Opportunities and is designed to increase awareness of prostate cancer prevention, research, and treatment as well as highlight the health disparities observed in Black communities. According to the Florida Department of Health, prostate cancer incidence and mortality rates among Black men living in Duval County are higher compared to men of other races and ethnicities. Therefore, there is a need for programs like ProTALKS that focus on early detection strategies and promoting community resources. In collaboration with the Prostate Health Education Network (PHEN), The American Legion Post 197, and Florida Blue, ProTALKS has increased access to services such as prostate cancer screening and evidence-based information. Community events implemented by ProTALKS bring together oncologists, researchers, key community leaders, health educators, and providers to educate and promote positive health behavior changes among high-risk communities. In addition to hosting health fairs, ProTalks has hosted grilling competitions and community awareness walks to further educate the community about prostate cancer prevention, screening, and research. ProTALKS also shares information through the local newspaper, The Jacksonville Free Press, The Lynn &amp; Friends radio show, and social media platforms. Since its start in 2021, with support from the Florida-California Cancer Research, Education, and Engagement (CaRE2) Health Equity Center, ProTALKS has implemented more than 10 community events with over 1,000 community members from Jacksonville, Florida. ProTALKS, in collaboration with CaRE2, continues to disseminate information about cancer screening, the importance of clinical trial participation, and donating biospecimens for cancer research. Although ProTALKS has been successful in its mission, there have been challenges throughout its implementation. For example, one challenge has been increasing the number of community members attending events and using appropriate marketing techniques to promote ProTALKS’ activities. Future implications to avoid challenges include recruiting more volunteers, and partnering with other community organizations in Duval County. Citation Format: Lynn Jones-Turpin, Ileana Guzman, Brooke Hensel, Fern Webb. ProTALKS: A community outreach project founded by a graduate of the CaRE2 Community Scientist Research Advocacy training program, Mrs. Lynn Jones-Turpin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1292.

Abstract 2146: Race-related differential immunoreactivity of enolase autoantibodies in patients with prostate cancer

Abstract INTRODUCTION AND OBJECTIVE: Enolase-1 (ENO1) and -2 (ENO2) are implicated in tumor metabolic and aggressive functions. Like prostate specific membrane antigen (PSMA), they localize to the tumor cell surface and are potential theranostics targets. ENO autoantibodies were reported by our group in prostate cancer (PCa) patients but their immunoreactivity to ENO1/2 isoforms was not defined. Differential ENO immunoreactivity in docetaxel-resistant (DR) PCa cells between African American (AA) and European American (EA) PCa patients was also reported. Our objective was to investigate the role of ENO isoforms in the race-related differential ENO immunoreactivity of PCa patients. METHODS: PCa patient sera (41 AA, 68 EA) were obtained from Loma Linda University Biospecimen Laboratory. Western blotting (WB) analysis, using patient sera and monoclonal antibodies to ENO1 and ENO2, was done against lysates from docetaxel-sensitive (DS) and DR PCa cell lines and against recombinant (rec) ENO1 and ENO2 to assess ENO isoform expression and detect ENO autoantibodies. Scratch-wound assay was performed to evaluate AA and EA anti-ENO driven inhibition of DR PCa cell migration. Student’s T-test and Chi-squared analyses were performed with p&amp;lt;0.05 deemed significant. RESULTS: ENO1 expression was robust in all assessed DS and DR cell lines. ENO2 was detected in DS cells but was significantly reduced in DR cells. PSMA expression was lost in cells expressing ENO1 and neuroendocrine markers. Anti-ENO EA sera reacted in WB with the expected 50 kD band in both DS and DR PCa cells, but anti-ENO AA sera reacted preferentially with this band in DS cells. Strong immunoreactivity was noted against recENO1 in AA and EA sera (7% vs 28%, p&amp;lt;0.01) and against recENO2 in AA and EA sera (24% vs 35%, p=0.23). EA, but not AA, ENO autoantibodies significantly inhibited DR cell migration, and their pre-absorption with recENO1 diminished this inhibitory effect. CONCLUSIONS: Autoantibodies to ENO1 and ENO2 were identified in EA and AA PCa patient sera. Weaker ENO1 immunoreactivity was seen in sera from AA PCa patients, corresponding with weaker inhibition of DR PCa cell migration compared to EA patient sera. Unlike PSMA and ENO2, ENO1 expression was robust in neuroendocrine-like DR PCa cell lines. Future studies will correlate the presence of ENO autoantibodies with clinicopathologic parameters in a larger patient cohort. Defining mechanisms underlying the race-related differential ENO immunoreactivity may identify novel biological determinants of PCa health disparities and uncover the theranostic potential of tumor surface ENO1. Citation Format: Kai Wen Cheng, Carlos J. Diaz Osterman, Krystal Santiago, Michael Reeves, Diano Lozano, Pedro Ochoa, Alfonso Duran, Saied Mirshahidi, Brian R. Hu, Frankis Almaguel, Carlos A. Casiano. Race-related differential immunoreactivity of enolase autoantibodies in patients with prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2146.

Prostate cancer genetic risk and associated aggressive disease in men of African ancestry

African ancestry is a significant risk factor for prostate cancer and advanced disease. Yet, genetic studies have largely been conducted outside the context of Sub-Saharan Africa, identifying 278 common risk variants contributing to a multiethnic polygenic risk score, with rare variants focused on a panel of roughly 20 pathogenic genes. Based on this knowledge, we are unable to determine polygenic risk or differentiate prostate cancer status interrogating whole genome data for 113 Black South African men. To further assess for potentially functional common and rare variant associations, here we interrogate 247,780 exomic variants for 798 Black South African men using a case versus control or aggressive versus non-aggressive study design. Notable genes of interest include HCP5, RFX6 and H3C1 for risk, and MKI67 and KLF5 for aggressive disease. Our study highlights the need for further inclusion across the African diaspora to establish African-relevant risk models aimed at reducing prostate cancer health disparities.

Abstract B025: A multi-omic, spatial approach using patient prostatectomies to identify actionable drug targets for combatting prostate cancer health disparities

Abstract Prostate cancer (PC) is the most commonly diagnosed cancer among African American men (AA) and continues to be the largest difference in absolute incidence and cancer-specific deaths between AA and Caucasian men (CA). AA have a 70% higher incidence of PC than CA and over a 2 times higher mortality rate. Among men undergoing prostate biopsy In an equal access setting (i.e. the VA), AA are ~50% more likely to have PC and ~80% more likely to have high-grade PC than CA. The frequency of PC-associated genetic alterations and differences in oncogene expression in PCs is altered from CA and AA. While social economic status and environmental factors may play a role in PC health disparities, there are inherent genetic/molecular differences that account for the differences in PC outcomes between CA and AA. We sought to test our hypothesis that there is a subset of actionable gene products that are essential for enhanced PC progression in AA. A focused and clinically informed CRISPR knockout screen was conducted to identify and functionally validate race-specific actionable genes that contribute to the increased risks of fatal PC in AA. The CRISPR screen was designed leveraging a radical prostatectomy transcriptomic dataset from the Durham VA Medical Center that was linked with long-term clinical outcome data. This unique dataset consists of ~600-profiled radical prostatectomy samples of which over 50% were from AA patients. A Cox hazard analysis revealed differentially expressed genes (DEGs) which are positively associated with an increased risk of metastatic disease unique to AA PC patients. To identify drug-targetable genes, these DEGs were filtered against the drug-gene interaction database (DGIdb). This approach yielded 89 genes positively associated with an increased risk of metastatic outcome in AA and 236 genes in CA only. The CRISPR KO screen resulted in 19 genes significantly depleted genes. Of these 19 hits, 11 genes were genes associated with metastasis in AA, while 8 hits were CA genes, with 5 of 11 AA hits having documented small molecule inhibitors. To further prioritize our hits, we have conducted a spatial transcriptomic analysis of radical prostatectomy tissues from AA and CA PCs. By standard H and E staining these tumors look quite similar. But spatial analysis of AA compared to CA tissues revealed differences in immune cells and cells associated with the tumor microenvironment. This integrative multi-omic approach reveals new cell identities that may contribute to the aggressive pathogenicity of PC in AA compared to CA. CRISPR models and small molecule inhibitors of our top candidates will be used to investigate the druggability of these DEGs. This study lays the groundwork for potential therapeutics targeted toward PC in AA men. Citation Format: Felipe Segato Dezem, Aiza Akhtar, Arjumand Wanj, Sunyoung You, Hannah Chasteen, So Young Kim, Jasmine Plummer, Everardo Macias. A multi-omic, spatial approach using patient prostatectomies to identify actionable drug targets for combatting prostate cancer health disparities [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr B025.

Abstract IA047: A multiomic approach towards identifying actionable targets to combat prostate cancer health disparities

Abstract Prostate cancer (PC) is the most commonly diagnosed cancer among African American men (AA) and continues to be the largest difference in absolute incidence and cancer specific deaths between AA and Caucasian men (CA). AA have a 70% higher incidence of PC than CA and over a 2 times higher mortality rate. Among men undergoing prostate biopsy In an equal access setting (i.e. the VA), AA are ~50% more likely to have PC and ~80% more likely to have high-grade PC than CA. The frequency of PC associated genetic alterations and differences in oncogene expression in PCs is altered from CA and AA. While social economic status and environmental factors may play a role in PC health disparities, there are inherent genetic/molecular differences that account for the differences in PC outcomes between CA and AA. We sought to test our hypothesis that there is subset of actionable gene products that are essential for enhanced PC progression in AA. A focused and clinically informed CRISPR knockout screen was conducted to identify and functionally validate race specific actionable genes that contribute to the increased risks of fatal PC in AA. The CRISPR screen was designed leveraging a radical prostatectomy trancscriptomic dataset from the Durham VA Medical Center that was linked with long-term clinical outcome data. This unique dataset consists of ~600-profiled radical prostatectomy samples of which over 50% were from AA patients. A cox hazard analysis revealed differentially expressed genes (DEGs) which positively associated with increased risk of metastatic disease unique to AA PC patients. To identify drug targetable genes, these DEGs were filtered against the drug gene interaction database (DGIdb).This approach yielded 89 genes positively associated with increased risk of metastatic outcome in AA and 236 genes in CA only. The CRISPR KO screen resulted in 19 genes significantly depleted genes. Of these 19 hits, 11 genes were genes associated with metastasis in AA, while 8 hits were CA genes, with 5 of 11 AA hits have documented small molecule inhibitors. To further prioritize our hits, we have conducted spatial transcriptomic analysis of radical prostatectomy tissues from AA and CA PCs. By standard H and E staining these tumors looking quite similar. But spatial analysis of AA compared to CA tissues revealed differences in immune cells and cells associated with tumor microenvironment. These integative multiomic approach reveals new cell identities that may contribute to the aggressive pathogenicity of PC in AA compared to CA. CRISPR models and small molecule inhibitors of our top candidates will be used in investigate druggability of these DEGs. This study lays the groundwork for potential therapeutics targeted towards PC in AA men. Citation Format: Felipe Dezem, Aiza Akhtar, Sungyong You, So Young Kim, Jasmine Plummer, Everardo Macias. A multiomic approach towards identifying actionable targets to combat prostate cancer health disparities [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr IA047.

Abstract C061: The impact of the BRG1/BRM-associated factor (BAF) complex on the androgen receptor cistrome in African American prostate cancer

Abstract We aimed to establish in prostate cancer (PCa) how and why the androgen receptor displays differential functions in a manner driven by genomic ancestry, namely between African American (AA) and European American (EA) PCa, with the goal to assess how this may contribute to PCa health disparities. We utilized EA and AA non-malignant prostate and PCa cell models with confirmed genomic ancestry and defined the basal and dihydrotestosterone (DHT)-regulated AR and H3K27ac cistromes using CUT&amp;RUN, and integrated these data with publicly available genomic counterparts. The DHT-dependent AR and H3K27ac cistromes significantly overlapped within AA cells and EA cells but there was significantly less overlap between AA and EA cells. For example, H3K27ac distributions were frequent (~15-20k sites) in each of non-malignant AA RC43N and EA HPr1AR, and malignant RC43T and LNCaP, and the significance of the overlaps were comparable for basal and DHT treated cells, but this was not significantly impacted by ancestry. By contrast the AR cistrome was highly DHT-dependent, with ~2k sites notably in LNCaP and RC43T, which very significantly overlapped with H3K27ac in the same cells but significantly less so across cells. Thus, although the H3K27ac cistrome was comparable across cells, the overlap with AR was driven by genomic ancestry. To investigate this, we focused on the BAF complexes as previously we identified reduced expression of a key component, SMARCA5, in AA PCa. These large multimeric complexes regulate nucleosome positioning during gene transcription and DNA repair. In PCa, the cBAF complex impacts different transcription factors, including ERG, and it is tempting to speculate that the corruption of cBAF identified in AA PCa phenocopies the impact of TMPRSS2-ETS impact observed in EA PCa. To test the possibility that the cBAF complex corrupts AR genomic functions in AA PCa we exploited scRNA-Seq data from PCa organoids from the Rb and Pten double knockout (PBCre4:Rb1f/f:Pten f/f ) to establish that expression of genes in the cBAF genes complex were collectively significantly altered in neuroendocrine PCa (NEPC) and Pouf23 androgen indifferent lineages. Secondly, knockdown of another cBAF component, SMARCC1, enhanced Enzalutamide sensitivity in same organoids. Finally, to test the impact of cBAF complex on AR signaling we have generated AA and EA PCa cell lines that stably express dCRISPR-activator (VP64) or repressor (KRAB) proteins and designed gRNAs to regulate expression of, for example, SMARCA5 and measure the impact on the AR cistrome and function. In summary, these findings identified that the shared AR and H3K27ac cistromes are driven by genomic ancestry, and that reduced expression of SMARCA5 and other components of the cBAF complex are significant in AA and advanced PCa, and impact AR signaling. Our future directions are focused on how SMARCA5 expression disrupts the balance between transcription factor functions, such as for the AR and other transcription factors, and effective DNA repair. Citation Format: Shahid S. Hussain, Debasis Nayak, David W. Goodrich, Clayton Yates, Moray Campbell. The impact of the BRG1/BRM-associated factor (BAF) complex on the androgen receptor cistrome in African American prostate cancer [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C061.

Linking African ancestral substructure to prostate cancer health disparities

Prostate cancer (PCa) is a significant health burden in Sub-Saharan Africa, with mortality rates loosely linked to African ancestry. Yet studies aimed at identifying contributing risk factors are lacking within the continent and as such exclude for significant ancestral diversity. Here, we investigate a series of epidemiological demographic and lifestyle risk factors for 1387 men recruited as part of the multi-ethnic Southern African Prostate Cancer Study (SAPCS). We found poverty to be a decisive factor for disease grade and age at diagnosis, with other notably significant PCa associated risk factors including sexually transmitted diseases, erectile dysfunction, gynaecomastia, and vertex or complete pattern balding. Aligned with African American data, Black ethnicity showed significant risk for PCa diagnosis (OR = 1.44, 95% CI 1.05–2.00), and aggressive disease presentation (ISUP ≥ 4: OR = 2.25, 95% CI 1.49–3.40). New to this study, we demonstrate African ancestral population substructure associated PCa disparity, observing increased risk for advanced disease for the southern African Tsonga people (ISUP ≥ 4: OR = 3.43, 95% CI 1.62–7.27). Conversely, South African Coloured were less likely to be diagnosed with aggressive disease overall (ISUP ≥ 3: OR = 0.38, 95% 0.17–0.85). Understanding the basis for PCa health disparities calls for African inclusion, however, lack of available data has limited the power to begin discussions. Here, focusing on arguably the largest study of its kind for the African continent, we draw attention to the contribution of within African ancestral diversity as a contributing factor to PCa health disparities within the genetically diverse region of southern Africa.

Alterations in the Epigenetic Machinery Associated with Prostate Cancer Health Disparities

Prostate cancer is driven by acquired genetic alterations, including those impacting the epigenetic machinery. With African ancestry as a significant risk factor for aggressive disease, we hypothesize that dysregulation among the roughly 656 epigenetic genes may contribute to prostate cancer health disparities. Investigating prostate tumor genomic data from 109 men of southern African and 56 men of European Australian ancestry, we found that African-derived tumors present with a longer tail of epigenetic driver gene candidates (72 versus 10). Biased towards African-specific drivers (63 versus 9 shared), many are novel to prostate cancer (18/63), including several putative therapeutic targets (CHD7, DPF3, POLR1B, SETD1B, UBTF, and VPS72). Through clustering of all variant types and copy number alterations, we describe two epigenetic PCa taxonomies capable of differentiating patients by ancestry and predicted clinical outcomes. We identified the top genes in African- and European-derived tumors representing a multifunctional “generic machinery”, the alteration of which may be instrumental in epigenetic dysregulation and prostate tumorigenesis. In conclusion, numerous somatic alterations in the epigenetic machinery drive prostate carcinogenesis, but African-derived tumors appear to achieve this state with greater diversity among such alterations. The greater novelty observed in African-derived tumors illustrates the significant clinical benefit to be derived from a much needed African-tailored approach to prostate cancer healthcare aimed at reducing prostate cancer health disparities.

Abstract B036: Immune cell profiling of human prostate tumors identifies a protective and pathological role for intratumoral mast cells in the development of biochemical recurrence and metastasis

Abstract Background: Immunobiological factors may, in part, contribute to racial disparities in prostate cancer (PCa), the second leading cause of cancer-related death for US men. African American (AA) men face a greater risk of developing PCa and having a poorer outcome of this disease, compared to Caucasian American (CA) men. The goal of this study is to identify immune-specific differences influencing PCa health disparity as well as PCa progression. Methods: Ex vivo tumor biopsies were obtained following radical prostatectomy (RP) from 51 treatment-naïve patients (26 AA, 25 CA) under approved IRB protocols. Total RNA from fresh frozen tissue was isolated and amplified by PCR using NanoString multiplexed target enrichment protocols. We evaluated differences in resulting transcripts by self-reported race, pathology, and other clinical and pathologic features. Relative abundances of immune cell subsets were determined using computational methods, including previously published deconvolution algorithms, to estimate cellular content. Results: We identified differentially expressed genes between AA and CA tumors that are characterized by genes regulating Natural Killer (NK) cell function and Wnt signaling cancer pathways. Among the entire cohort, high expression of two of these differentially expressed genes, DVL2 and MAP3K5, were associated with worse biochemical recurrence (BCR)-free and metastasis-free survival. No difference in immune cell abundance was observed by self-reported race. Strikingly, among the entire cohort, low abundance of intratumoral mast cells was also associated with worse PCa pathology and poorer BCR-free and metastasis-free survival. Conclusions: Using a race-matched military cohort, we found that AA and CA tumors differ in the expression levels of Wnt and NK signaling-related pathways, yet cellular estimations of immune abundance did not significantly differ. Remarkably, the level of mast cell abundance within tumors at time of RP may be protective and prolong BCR-free and metastasis-free survival of patients. These types of in-depth immune profiling assessments have the potential to guide precision medicine and treatment decisions in the clinic. Disclaimer: The contents of this publication are the sole responsibility of the author(s) and do not necessarily reflect the views, opinions or policies of Uniformed Services University of the Health Sciences (USUHS), The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., the Department of Defense (DoD), the Departments of the Army, Navy, or Air Force. Mention of trade names, commercial products, or organizations does not imply endorsement by the U.S. Government. Citation Format: Cara Schafer, Jiji Jiang, Sally Elsamanoudi, Darryl Nousome, Denise Young, Yingjie Song, Isabell Sesterhenn, Gregory Chesnut, Shyh-Han Tan. Immune cell profiling of human prostate tumors identifies a protective and pathological role for intratumoral mast cells in the development of biochemical recurrence and metastasis [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr B036.

Prostate cancer metastasis and health disparities: a systematic review.

Prostate cancer (PCa), one of the most prevalent malignancies affecting men, significantly contributes to increased mortality rates worldwide. While the causative death is due to advanced metastatic disease, this occurrence disproportionately impacts men of African descent compared to men of European descent. In this review, we describe potential mechanisms underlying PCa metastases disparities and current treatments for metastatic disease among these populations, differences in treatment outcomes, and survival rates, in hopes of highlighting a need to address disparities in PCa metastases. We reviewed existing literature using databases such as PubMed, Google Scholar, and Science Direct using the following keywords: "prostate cancer metastases", "metastatic prostate cancer disparity", "metastatic prostate cancer diagnosis and treatment", "prostate cancer genetic differences and mechanisms", "genetic differences and prostate tumor microenvironment", and "men of African descent and access to clinical treatments". The inclusion criteria for literature usage were original research articles and review articles. Studies indicate unique genetic signatures and molecular mechanisms such as Epithelial-Mesenchymal Transition (EMT), inflammation, and growth hormone signaling involved in metastatic PCa disparities. Clinical studies also demonstrate differences in treatment outcomes that are race-specific, for example, patients of African descent have a better response to enzalutamide and immunotherapy yet have less access to these drugs as compared to patients of European descent. Growing evidence suggests a connection between a patient's genetic profile, the prostate tumor microenvironment, and social determinants of health that contribute to the aggressiveness of metastatic disease and treatment outcomes. With several potential pathways highlighted, the limitations in current diagnostic and therapeutic applications that target disparity in PCa metastases warrant rigorous research attention.

Mitochondrial Alterations in Prostate Cancer: Roles in Pathobiology and Racial Disparities.

Prostate cancer (PCa) affects millions of men worldwide and is a major cause of cancer-related mortality. Race-associated PCa health disparities are also common and are of both social and clinical concern. Most PCa is diagnosed early due to PSA-based screening, but it fails to discern between indolent and aggressive PCa. Androgen or androgen receptor-targeted therapies are standard care of treatment for locally advanced and metastatic disease, but therapy resistance is common. Mitochondria, the powerhouse of cells, are unique subcellular organelles that have their own genome. A large majority of mitochondrial proteins are, however, nuclear-encoded and imported after cytoplasmic translation. Mitochondrial alterations are common in cancer, including PCa, leading to their altered functions. Aberrant mitochondrial function affects nuclear gene expression in retrograde signaling and promotes tumor-supportive stromal remodeling. In this article, we discuss mitochondrial alterations that have been reported in PCa and review the literature related to their roles in PCa pathobiology, therapy resistance, and racial disparities. We also discuss the translational potential of mitochondrial alterations as prognostic biomarkers and as effective targets for PCa therapy.

Health disparities in metastatic hormone-sensitive prostate cancer (mHSPC) presentations and outcomes among Hispanic Americans (HA) versus non-Hispanic Whites (NHW).

31 Background: Multiple retrospective studies conducted have demonstrated disparities in access to care and treatment rates for prostate cancer between HA and NHW. We sought to understand the differences in prostate cancer presenting characteristics, prognosis, and outcomes between the two ethnic groups who presented to the University of Arizona Cancer Center (UACC), which serves a large Hispanic community. Methods: A retrospective analysis of mHSPC adenocarcinoma patients who presented to UACC from 2016 to 2022 was conducted. Patients must have had genetic testing to be included. Patients with no metastasis and incomplete data were excluded. Continuous data were analyzed using t-tests or Wilcoxon Rank sum tests depending on whether they were normally distributed. Categorical variables were analyzed using X2 Tests or Fisher's exact tests. Time to Event data was analyzed using Kaplan-Meier Methods. Results: 83 patients were included with 38.5% HA. No difference was observed between the ethnic groups by median age at presentation (66 years), race (90% white), obesity (40% BMI&gt;30), personal cancer history (10%), or family history of cancer (48%). HA were more likely to have a smoking (69%) and alcohol (63%) history compared to NHW (54% and 39%, respectively; p= 0.04). On presentation, 56% of HA were ECOG 0 compared to 22% of NHW (p=0.001). At the time of diagnosis, HA had median PSA levels of 111.5 ng/ml compared to 52.6 ng/ml in NHW (p=0.12). Gleason Grade Group ≥4 in 73% HA vs 79% in NHW (p=0.61). 41% of HA presented with T4 disease compared to 14% of NHW (p=0.01). 69% of HA presented with N1 disease vs 61% of NHW (p=0.85). 41% of HA presented with visceral metastasis, M1c, compared to 16% of NHW (p=0.04). The median time to first-line (1L) treatment was 1 month in HA compared to 3 months for NHW (p&lt;0.01). 84% of all patients had 1L combination therapy. Abiraterone plus ADT was 1L in 47% of HA compared to 20% of NHW (p=0.06). ADT plus androgen receptor blocker was 1L in 41% of NHW compared to 28% of HA (p=0.06). Median PSA response 3 months after starting treatment was 0.8 ng/ml in HA vs 3.96 ng/ml NHW (p=0.05). The median time to 2L was 20 months for HA vs 11 months in NHW (p=0.05). Conclusions: HA in our study presented with higher PSA, more locally advanced disease, and increased rates of visceral metastases, necessitating a shorter time interval to 1L therapy. HA demonstrated a more favorable response to 1L treatment, noted by lower PSA at 3 months and time to the next line of treatment. Overall survival was not calculated due to the small sample size with only 11 (1 HA vs 10 NHW) total deaths. The Hispanic Americans Prostate Cancer Comprehensive Genomic Profiling Study's (THAPCA-GPS) future investigations aim to delineate the pathogenetic differences between HA and NHW and may reduce healthcare disparities and improve clinical outcomes in HA patients.

Genomic profiling between Hispanic Americans (HA) and non-Hispanic (NHW) with advanced prostate cancer: A retrospective analysis of tissue, liquid, and germline testing.

30 Background: Genomic testing through the employment of somatic and germline testing has become increasingly relevant in determining the prognosis and targeted therapies for advanced prostate cancer patients. Prostate cancer health disparities resulting in worse presentations and clinical outcomes have been observed in HA compared to NHW. Understanding the prevalence of different genomic alterations is paramount to bridge the gap between the two ethnic groups. Methods: This is a retrospective analysis of 190 metastatic prostate adenocarcinoma patients with 24.2% HA who presented to the University of Arizona Cancer Center from 2015 to 2022. Patients in both groups may have undergone more than one type of testing. Homologous recombination repair (HRR) included ATM, BRCA1/2, BARD1, BRIP1, CDK12, CHEK1/2, FANCA/L, HDAC2, PALB2, RAD-51B/1C/51D, or 54L. Tissue-agnostic therapy approvals are dMMR, MSI-H, TMB-High, BRAF V600E, and NTRK/RET fusion. The proportion of HA and NHW was determined, and the statistical significance of the differences was reported using Chi2 or Fisher’s Exact test. Results: 43.6%, 34.7%, and 38.9% of patients had somatic tissue, liquid, and germline testing, respectively analyzed for pathogenic variants. TMB-High &gt;10 (30% vs 3.6%, p=0.02), PD-L1 CPS&gt;5 (9.4% vs 0%, p=0.03) and TMPRSS2-ERG fusion (37.5 vs 7.8%, p=0.0009) had higher proportion in HA compared to NHW. No test showed a difference in BRCA 1/2 or another HRR deficiency actionable mutation between the two ethnicities. There were no other statistically significant differences in common mutations or variants of unknown significance among groups. Conclusions: Liquid and tissue biopsies indicated a difference in proportions for tissue-agnostic and immune-oncology therapeutic indications, being more prevalent in HA. TMPRSS2-ERG fusions have differences in PC development and progression by race and now potentially by ethnicity, as shown by our study. Our review revealed increased germline and somatic testing over time according to targeted therapies approval and guideline recommendations, although, there remains a critical need for advancing genomic sequencing efforts for underrepresented HA. The Hispanic Americans Prostate Cancer Comprehensive Genomic Profiling Study's (THAPCA-GPS) future investigations aim to delineate the pathogenetic differences between HA and NHW and may reduce healthcare disparities and improve clinical outcomes in HA patients. [Table: see text]

Abstract IA041: Basic science mechanisms associated with bone tumor microenvironment and health disparities in breast and prostate cancer

Abstract Prostate cancer (PCa) and breast cancer (BCa) are leading causes of cancer related deaths in American men and women, and morbidity is due to metastasis preferentially to bone. Compared to Caucasian American (CA), African American (AA) men and women have a higher bone density, as well as mortality rate due to bone metastasis. Recent studies have shown that high mobility group two (HMGA2), a non-histone chromatin binding protein, plays a critical role in promoting epithelial-mesenchymal transition (EMT) and metastasis. HMGA2 full-length/wild-type and truncated (without the 3’UTR) isoforms have been shown to be overexpressed in several cancers, however their distinct roles in metastasis have not been reported. Our laboratory focuses on tumor-micronenvironmental interactions, particularly, how PCa cells interact with bone at the metastatic site. We have previously published that PCa cells may degrade hydroxyapatite, the major inorganic component of bone, to release calcium which promotes paracrine cell proliferation and migration, and this signaling increases with increased bone density. We hypothesize that EMT is associated with prostate health disparities and that HMGA2 isoforms may play differential roles at the bone metastatic site. We examined EMT marker expression in breast and prostate patient tissue and cell lines by immunohistochemistry (IHC), RNA In Situ Hybridization (RISH), western blot, and real-time PCR. Next, LNCaP PCa cell line stably overexpressing either full length or truncated HMGA2 was co-cultured with low (100 mg) or high (200 mg) hydroxyapatite, demineralized bone matrix or human ground bone matrix, for 6 days followed by collection of condition media (CM). CM was added to parental LNCaP cells for various time points followed by analysis of paracrine cell proliferation using MTS assay, cell migration across collagen using boyden chamber, and the effect on various pathways using western blot analysis. EMT marker (Snail and Cathepsin L) protein expression was higher in AA normal and cancer tissue compared to CA, while it was intermediate in Bahamian tissue. Wild-type HMGA2 mRNA expression was higher in metastatic patient tissue compared to truncated HMGA2, and higher in AA compared to CA tissue. CM taken from LNCaP cells overexpressing wild-type and truncated HMGA2 co-cultured with hydroxyapatite, demineralized bone matrix or ground bone matrix when added to parental LNCaP cells led to higher paracrine cell proliferation and paracrine cell migration. This was associated with MAPK activation that could be abrogated by MAPK inhibitor, UO126. These results indicate that EMT is higher in AA compared to CA. Additionally, both wild-type and truncated HMGA2 interaction with bone matrix promotes paracrine cell proliferation and migration via ERK signaling. Our study shows that wild-type and truncated isoforms of HMGA2 mediate PCa/bone interactions which may lead to increased bone metastasis, particularly in African American men that have higher bone density. Citation Format: Taaliah Campbell, Ohuod Hawsawi, Bor-Jang Hwang, Liza J. Burton, Quentin Loyd, Veronica Henderson, Simone Howard, Camille Ragine, Robin Roberts, Andrew Gachii, Valerie Odero-Marah. Basic science mechanisms associated with bone tumor microenvironment and health disparities in breast and prostate cancer [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr IA041.

Abstract IA025: Utilizing Visium spatial transcriptomics to investigate prostate cancer disparity in men of African descent

Abstract People of African descent suffer more from cancer compared to other racial groups in terms of morbidity and mortality. Surveillance, Epidemiology, and End Results (SEER) reports Black men and women to have the highest diagnoses and highest cancer death rate. The reported cancer disparity statistic is also reflected by cancer type; prostate cancer was shown to be one of the top causes of cancer death in all cancer types, and the second leading cause of death, after lung cancer, in men. Men of African Descent, however, have more than a 2-fold increased mortality rate of prostate cancer compared to other ancestral populations. Cancer is considered a genetic disease, and prostate cancer has a heritability of 58%. Most studies however, do not capture the genetic heterogeneity found in men of African Descent, nor histological and morphological profiles that would provide prognostic and diagnostic markers for targeted and personalized therapeutic treatment options. Visium Spatial Transcriptomics is a method that maps transcriptomics data to the location within the tissue region that is being analyzed. Instead of being limited to a small piece of DNA or RNA, spatial transcriptomics enables high-resolution assessment of spatial gene expression across tissue sections. This technology assiduously probes the transcriptome of tissues samples in an untargeted way. Spatial Transcriptomics involves cutting edge technology that provides great potential to capture the cellular landscape of men with the heaviest burden of prostate cancer. The Visium platform by 10X Genomics is able to interrogate more than 10,000 transcripts per capture region. The protocol involves a comprehensive process from tissue collection to next generation sequencing following a bioinformatics pipeline. The complete protocol from beginning to end requires a collaboration of clinicians, pathologists, basic scientists, and bioinformaticians. This means that access to resources is imperative to the success of this technique. Unfortunately, low resource institutions are at a disadvantage in being able to perform the entire protocol. This fact is yet another type of health disparity. This observation, however, provides great opportunities to establish collaborations with other institutions. Closing the gap between higher and lower resource investigations would be vital in addressing prostate cancer health disparity using spatial transcriptomics. I will share my observation, learning, experimentation, and joint participation effort experience with Visium Spatial Transcriptomics in my quest to understand the genetic architecture of men of African descent that has them at a prolific risk for prostate cancer. Citation Format: Maxine S. Harlemon, Ana C. Millena, Bor-Jang Hwang, Valerie Odero-Marah. Utilizing Visium spatial transcriptomics to investigate prostate cancer disparity in men of African descent [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr IA025.

Vitamin D and Systems Biology.

The biological actions of the vitamin D receptor (VDR) have been investigated intensively for over 100 years and has led to the identification of significant insights into the repertoire of its biological actions. These were initially established to be centered on the regulation of calcium transport in the colon and deposition in bone. Beyond these well-known calcemic roles, other roles have emerged in the regulation of cell differentiation processes and have an impact on metabolism. The purpose of the current review is to consider where applying systems biology (SB) approaches may begin to generate a more precise understanding of where the VDR is, and is not, biologically impactful. Two SB approaches have been developed and begun to reveal insight into VDR biological functions. In a top-down SB approach genome-wide scale data are statistically analyzed, and from which a role for the VDR emerges in terms of being a hub in a biological network. Such approaches have confirmed significant roles, for example, in myeloid differentiation and the control of inflammation and innate immunity. In a bottom-up SB approach, current biological understanding is built into a kinetic model which is then applied to existing biological data to explain the function and identify unknown behavior. To date, this has not been applied to the VDR, but has to the related ERα and identified previously unknown mechanisms of control. One arena where applying top-down and bottom-up SB approaches may be informative is in the setting of prostate cancer health disparities.

Health Burdens and SES in Alabama: Using Geographic Information System to Examine Prostate Cancer Health Disparity.

Simple SummaryThe focus of the research was to examine the relationship between Socioeconomic status and prostate cancer in Alabama’s Black Belt region. The cancer rate in Alabama is high, and the state has one of the highest rates of prostate cancer in the USA. The research aims to identify probable reasons, raise awareness, and propose cancer prevention policies. The Geographic Information System, a robust technology, has been adopted to understand Alabama’s county-level prostate cancer incidence and mortality and its association with socioeconomic and health disparities. The analysis indicated an apparent socioeconomic disparity between the Black Belt and Non-Black Belt counties of Alabama. The poverty rate is higher in Black Belt counties. The data revealed that the preexisting condition of diabetes and obesity is closely associated with prostate cancer. Also, incidence and mortality disparities strongly relate to socioeconomic status, and the preexisting condition of obesity and diabetes adds to prostate cancer incidences. Poverty is the root course of inequalities in education, income, and healthcare facilities, particularly among African Americans, contributing to Alabama’s health burden of prostate cancer. The study proposes effective health policy intervention to prevent and reduce prostate cases and mortality among underserved communities in Alabama.Socioeconomic disparities influence the risk of many diseases, including cancer. The cancer rate in Alabama is high, and the state has one of the highest rates of prostate cancer in the USA. Alabama’s counties are embedded with socioeconomic disparities, politics, race, ethnicity, and oppression, among which social equity and socioeconomic status (SES) been closely associated with prostate cancer. The Geographic Information System (GIS) has become a valuable technology in understanding public health in many applications, including cancer. This study integrates Alabama’s county-level prostate cancer incidence and mortality and its association with socioeconomic and health disparities. We conducted robust data mining from several data sources such as the Alabama State Cancer Profile data, Alabama Department of Health, American Cancer Society, Center for Disease Control, and National Cancer Institute. The research method is the Geographic Information System (GIS), and we employed prostate cancer data within GIS to understand Alabama’s prostate cancer prevalence regarding SES. The GIS analysis indicated an apparent socioeconomic disparity between the Black Belt and Non-Black Belt counties of Alabama. The Black Belt counties’ poverty rate is also remarkably higher than non-Black Belt counties. In addition, we analyzed the median household income by race. Our analysis demonstrates that the Asian background population in the state earned the highest median income compared to non-Hispanic whites and the African American population. Furthermore, the data revealed that the preexisting condition of diabetes and obesity is closely associated with prostate cancer. The GIS analysis suggests that prostate cancer incidence and mortality disparities are strongly related to SES. In addition, the preexisting condition of obesity and diabetes adds to prostate cancer incidences. Poverty also reflects inequalities in education, income, and healthcare facilities, particularly among African Americans, contributing to Alabama’s health burden of prostate cancer.

Racial differences in circulating mitochondria-derived peptides may contribute to prostate cancer health disparities.

The mitochondrial genome has small open reading frames (sORF) which produce measurable mitochondrial-derived peptides (MDPs), including humanin, SHLP2, and MOTS-c. Previously, among men undergoing prostate biopsy, we found higher serum SHLP2 was linked with lower prostate cancer(PC) risk in European American men (EAM), while null associations were found in African American men (AAM). Here, in different patients undergoing prostate biopsy, we tested the link between SHLP2, humanin and MOTS-c and PCrisk by race. Plasma SHLP2, humanin, and MOTS-c were measured in 198 men (50/49 EAM/AAM cases; 50/49 EAM/AAM controls) undergoing biopsy. Logistic and multinomial regression models tested associations between each MDP and PC diagnosis, low-grade (grade group, GG1) and high-grade (GG2-5). Models were adjusted for age, body mass index, digital rectal examination, and prostate specific antigen (PSA). We tested interactions between MDPs and race. Among controls, humanin was similar by race (p = 0.60), but both SHLP2 (p = 0.007) and MOTS-c (p = 0.026) were lower in AAM controls versus EAM controls. Among EAM, higher MDP values were associated with lower PC risk (all p ≤ 0.001), with null associations in AAM (all p-interactions ≤ 0.01). Similarly, higher MDP expression was associated with decreased risk of low- and high-grade PC in EAM (all p ≤ 0.005) with null associations in AAM. Higher MDP levels were associated with lower PC risk in EAM but not AAM. Generally, AAM controls had lower MDP levels. These data support MDPs and mitochondrial dysfunction in PC, suggesting greater dysfunction in AAM may contribute to excess PC risk. Future larger studies are needed to confirm these results.