Characterizing genetic risk at known prostate cancer susceptibility loci in African Americans

Genetic and biological drivers of prostate cancer disparities in Black men

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

Incidence trends and survival of metastatic prostate cancer with bone and visceral involvement: 2010-2019 surveillance, epidemiology, and end results

Background

The incidence of prostate cancer (PCa) has continued to increase since the US Preventive Services Task Force (USPSTF) recommendations against prostate-specific antigen (PSA)-based screening for all men in 2012, approximately half of additional diagnosed cases are advanced-stage, including regional PCa and metastatic PCa (mPCa). It is very important to investigate the shift in mPCa incidence and mPCa-related mortality risk, as the survival of mPCa remains poor.

Objective

To investigate the incidence temporal trend of mPCa stratified by metastatic site, including bone and visceral metastatic involvement, and potential survival improvements.

Materials

Based on the recently released Surveillance, Epidemiology, and End Results (SEER) data (2010-2019), the age-adjusted incidence rates of mPCa with bone and visceral involvement with annual percentage changes (APCs) were assessed by a joinpoint regression model in men aged 45 years and older by age and race groups, and potential recent improvements in overall survival (OS) and cancer-specific survival (CSS) were estimated by the Kaplan-Meier method and Cox regression model.

Results

From 2010 to 2019, a total of 19081 (84.8%) and 3413 (15.2%) mPCa patients with bone and visceral involvement, respectively, were recorded in the SEER database. Considering all races and age groups, the incidence rate of mPCa with bone metastasis remained stable during 2017-2019 (APC, 0.9%; p=0.421) after increasing during 2010-2017 (APC, 5.8%; p<0.001). For visceral metastasis, the incidence rate increased by 12.3% (p<0.001) per year from 2010-2019. Non-Hispanic Black men have higher incidence rates than other populations, and the Non-Hispanic Black to Non-Hispanic White incidence rates ratios of mPCa declined with the greater increasing pace of incidence of Non-Hispanic White men. There was a slight improvement in both OS and CSS among men with bone and visceral metastasis involvement when comparing the 2013-2016 period to the pre-2013 period.

Conclusion

Our findings show that the incidence of mPCa with bone and visceral involvement has increased in recent years and that there has been a potential improvement in survival. Future efforts are still needed to watch closely if the rising incidence trends continue.

Evidence of Novel Susceptibility Variants for Prostate Cancer and a Multiancestry Polygenic Risk Score Associated with Aggressive Disease in Men of African Ancestry

BACKGROUND

Genetic factors play an important role in prostate cancer (PCa) susceptibility.

OBJECTIVE

To discover common genetic variants contributing to the risk of PCa in men of African ancestry.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a meta-analysis of ten genome-wide association studies consisting of 19378 cases and 61620 controls of African ancestry.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Common genotyped and imputed variants were tested for their association with PCa risk. Novel susceptibility loci were identified and incorporated into a multiancestry polygenic risk score (PRS). The PRS was evaluated for associations with PCa risk and disease aggressiveness.

RESULTS AND LIMITATIONS

Nine novel susceptibility loci for PCa were identified, of which seven were only found or substantially more common in men of African ancestry, including an African-specific stop-gain variant in the prostate-specific gene anoctamin 7 (ANO7). A multiancestry PRS of 278 risk variants conferred strong associations with PCa risk in African ancestry studies (odds ratios [ORs] >3 and >5 for men in the top PRS decile and percentile, respectively). More importantly, compared with men in the 40-60% PRS category, men in the top PRS decile had a significantly higher risk of aggressive PCa (OR = 1.23, 95% confidence interval = 1.10-1.38, p = 4.4 × 10-4).

CONCLUSIONS

This study demonstrates the importance of large-scale genetic studies in men of African ancestry for a better understanding of PCa susceptibility in this high-risk population and suggests a potential clinical utility of PRS in differentiating between the risks of developing aggressive and nonaggressive disease in men of African ancestry.

PATIENT SUMMARY

In this large genetic study in men of African ancestry, we discovered nine novel prostate cancer (PCa) risk variants. We also showed that a multiancestry polygenic risk score was effective in stratifying PCa risk, and was able to differentiate risk of aggressive and nonaggressive disease.

Predictors of Prostate Cancer at Fusion Biopsy: The Role of Positive Family History, Hypertension, Diabetes, and Body Mass Index

BACKGROUND

PSA density and an elevated PI-RADS score are among the strongest predictors of prostate cancer (PCa) in a fusion biopsy. Positive family history, hypertension, diabetes, and obesity have also been associated with the risk of developing PCa. We aim to identify predictors of the prostate cancer detection rate (CDR) in a series of patients undergoing a fusion biopsy.

METHODS

We retrospectively evaluated 736 consecutive patients who underwent an elastic fusion biopsy from 2020 to 2022. Targeted biopsies (2-4 cores per MRI target) were followed by systematic mapping (10-12 cores). Clinically significant PCa (csPCa) was defined as ISUP score ≥ 2. Uni- and multi-variable logistic regression analyses were performed to identify predictors of CDR among age, body mass index (BMI), hypertension, diabetes, positive family history, PSA, a positive digital rectal examination (DRE), PSA density ≥ 0.15, previous negative biopsy status, PI-RADS score, and size of MRI lesion.

RESULTS

The median patients' age was 71 years, and median PSA was 6.6 ng/mL. A total of 20% of patients had a positive digital rectal examination. Suspicious lesions in mpMRI were scored as 3, 4, and 5 in 14.9%, 55.0%, and 17.5% of cases, respectively. The CDR was 63.2% for all cancers and 58.7% for csPCa. Only age (OR 1.04, p < 0.001), a positive DRE (OR 1.75, p = 0.04), PSA density (OR 2.68, p < 0.001), and elevated PI-RADS score (OR 4.02, p = 0.003) were significant predictors of the CDR in the multivariable analysis for overall PCa. The same associations were found for csPCa. The size of an MRI lesion was associated with the CDR only in uni-variable analysis (OR 1.07, p < 0.001). BMI, hypertension, diabetes, and a positive family history were not predictors of PCa.

CONCLUSIONS

In a series of patients selected for a fusion biopsy, positive family history, hypertension, diabetes, or BMI are not predictors of PCa detection. PSA-density and PI-RADS score are confirmed to be strong predictors of the CDR.

Underlying Features of Prostate Cancer-Statistics, Risk Factors, and Emerging Methods for Its Diagnosis

Prostate cancer (PCa) is the most frequently occurring type of malignant tumor and a leading cause of oncological death in men. PCa is very heterogeneous in terms of grade, phenotypes, and genetics, displaying complex features. This tumor often has indolent growth, not compromising the patient's quality of life, while its more aggressive forms can manifest rapid growth with progression to adjacent organs and spread to lymph nodes and bones. Nevertheless, the overtreatment of PCa patients leads to important physical, mental, and economic burdens, which can be avoided with careful monitoring. Early detection, even in the cases of locally advanced and metastatic tumors, provides a higher chance of cure, and patients can thus go through less aggressive treatments with fewer side effects. Furthermore, it is important to offer knowledge about how modifiable risk factors can be an effective method for reducing cancer risk. Innovations in PCa diagnostics and therapy are still required to overcome some of the limitations of the current screening techniques, in terms of specificity and sensitivity. In this context, this review provides a brief overview of PCa statistics, reporting its incidence and mortality rates worldwide, risk factors, and emerging screening strategies.

Alteration of Lipid Metabolism in Prostate Cancer: Multifaceted Oncologic Implications

Cancer is increasingly recognized as an extraordinarily heterogeneous disease featuring an intricate mutational landscape and vast intra- and intertumor variability on both genetic and phenotypic levels. Prostate cancer (PCa) is the second most prevalent malignant disease among men worldwide. A single metabolic program cannot epitomize the perplexing reprogramming of tumor metabolism needed to sustain the stemness of neoplastic cells and their prominent energy-consuming functional properties, such as intensive proliferation, uncontrolled growth, migration, and invasion. In cancerous tissue, lipids provide the structural integrity of biological membranes, supply energy, influence the regulation of redox homeostasis, contribute to plasticity, angiogenesis and microenvironment reshaping, mediate the modulation of the inflammatory response, and operate as signaling messengers, i.e., lipid mediators affecting myriad processes relevant for the development of the neoplasia. Comprehensive elucidation of the lipid metabolism alterations in PCa, the underlying regulatory mechanisms, and their implications in tumorigenesis and the progression of the disease are gaining growing research interest in the contemporary urologic oncology. Delineation of the unique metabolic signature of the PCa featuring major aberrant pathways including de novo lipogenesis, lipid uptake, storage and compositional reprogramming may provide novel, exciting, and promising avenues for improving diagnosis, risk stratification, and clinical management of such a complex and heterogeneous pathology.

The 17-Gene Genomic Prostate Score Test Is Prognostic for Outcomes After Primary External Beam Radiation Therapy in Men With Clinically Localized Prostate Cancer

PURPOSE

The Oncotype DX Genomic Prostate Score (GPS) assay has been validated as a strong prognostic indicator of adverse pathology, biochemical recurrence, distant metastasis (DM), and prostate cancer (PCa)-related death (PCD) in men with localized PCa after radical prostatectomy. However, it has yet to be tested in men undergoing external beam radiation therapy (EBRT), for whom assessing PCa progression risk could inform decisions on treatment intensity. We analyzed whether GPS results are associated with time to biochemical failure (BCF), DM, and PCD after EBRT in men with localized PCa and whether the association is modified by race.

METHODS AND MATERIALS

We conducted a retrospective study of men with localized PCa treated with EBRT at the VA Health Care System in Durham, NC from 2000 to 2016. Study endpoints were time to BCF per the Phoenix criteria, DM, and PCD. The association of GPS results, per 20-unit increase or dichotomous variable (0-40 vs 41-100), was evaluated with each endpoint using univariable and multivariable Cox proportional hazards models. Results were then stratified by race.

RESULTS

A total of 238 patients (69% Black) met the eligibility criteria. Median follow-up for patients who did not experience BCF was 7.6 years. GPS results per 20-unit increase were significantly associated with BCF (hazard ratio [HR], 3.62; 95% confidence interval [CI], 2.59-5.02), DM (HR, 4.48; 95% CI, 2.75-7.38), and PCD (HR, 5.36; 95% CI, 3.06-9.76) in univariable analysis. GPS results remained significant in multivariable models adjusted for baseline clinical and pathological factors, with HRs being similar to the univariable analysis. There was no significant interaction between the GPS assay and race (P = .923). HRs for BCF were similar in Black men (HR, 3.88; 95% CI, 2.40-6.24) versus non-Black men (HR, 4.01; 95% CI, 2.42-6.45).

CONCLUSIONS

Among men treated with EBRT, the GPS assay is a strong, independent prognostic indicator of time to BCF, DM, and PCD, and performs similarly in Black and non-Black men.

Review of prostate cancer genomic studies in Africa

Prostate cancer (PCa) is the second most commonly diagnosed in men worldwide and one of the most frequent cancers in men in Africa. The heterogeneity of this cancer fosters the need to identify potential genetic risk factors/biomarkers. Omics variations may significantly contribute to early diagnosis and personalized treatment. However, there are few genomic studies of this disease in African populations. This review sheds light on the status of genomics research on PCa in Africa and outlines the common variants identified thus far. The allele frequencies of the most significant SNPs in Afro-native, Afro-descendants, and European populations were compared. We advocate how these few but promising data will aid in understanding, better diagnosing, and precisely treating this cancer and the need for further collaborative research on the genomics of PCa in the African continent.

Testing the generalizability of ancestry-specific polygenic risk scores to predict prostate cancer in sub-Saharan Africa

BACKGROUND

Genome-wide association studies do not always replicate well across populations, limiting the generalizability of polygenic risk scores (PRS). Despite higher incidence and mortality rates of prostate cancer in men of African descent, much of what is known about cancer genetics comes from populations of European descent. To understand how well genetic predictions perform in different populations, we evaluated test characteristics of PRS from three previous studies using data from the UK Biobank and a novel dataset of 1298 prostate cancer cases and 1333 controls from Ghana, Nigeria, Senegal, and South Africa.

RESULTS

Allele frequency differences cause predicted risks of prostate cancer to vary across populations. However, natural selection is not the primary driver of these differences. Comparing continental datasets, we find that polygenic predictions of case vs. control status are more effective for European individuals (AUC 0.608-0.707, OR 2.37-5.71) than for African individuals (AUC 0.502-0.585, OR 0.95-2.01). Furthermore, PRS that leverage information from African Americans yield modest AUC and odds ratio improvements for sub-Saharan African individuals. These improvements were larger for West Africans than for South Africans. Finally, we find that existing PRS are largely unable to predict whether African individuals develop aggressive forms of prostate cancer, as specified by higher tumor stages or Gleason scores.

CONCLUSIONS

Genetic predictions of prostate cancer perform poorly if the study sample does not match the ancestry of the original GWAS. PRS built from European GWAS may be inadequate for application in non-European populations and perpetuate existing health disparities.

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.

Deciphering the polygenic basis of racial disparities in prostate cancer by an integrative analysis of genomic and transcriptomic data

Prostate cancer (PCa) prevalence in African Americans (AAs) is over 1.5 times the prevalence in European Americans (EAs). Among over a hundred index risk SNPs for PCa, only a few can be verified using the available AAs' data. Their relevance to the prevalence inequality and other racial disparities has not been fully determined. We investigated this issue by an integrative analysis of five public datasets. We categorized the datasets into two classes. The training class consisted of the datasets generated by three genome-wide association studies. The test class contained the TCGA prostate carcinoma data and the data of African and European super-populations in the 1000-Genome project. The polygenic risk scores (PRS) of test samples for cancer occurrence were calculated according to the effects of genetic variants estimated from the training samples. We obtained the following findings. Africans' PRSs are higher than Europeans' scores (p << 0.01); AA patients' PRSs are higher than EA patients' scores (p<3×10-9); the patients with tumors presenting fusion or abnormal expression in ERG and other ETS family genes have lower PRSs than the patients without such aberrations (p < 7×10-5); five tumor progression-related genes have the expression levels being significantly correlated with PRS (FDR<0.01). Additional simulation analysis shows that the high PCa prevalence in African populations makes it challenging to identify individual risk variants using African men's data. The index risk SNPs-based PRS is compatible with the observed racial disparity in PCa prevalence and ETS abnormal cancers may be less heritable compared to other subtypes.

DNA Repair Pathways and Their Association With Lethal Prostate Cancer in African American and European American Men

Background

Altered DNA damage response (DDR) has emerged as an important mechanism for the development of aggressive prostate cancer among men of European ancestry but not other ancestry groups. Because common mechanisms for aggressive disease are expected, we explored a large panel of DDR genes and pathways to demonstrate that DDR alterations contribute to development of aggressive prostate cancer in both African American and European American men.

Methods

We performed a case-case study of 764 African American and European American men with lethal or indolent prostate cancer treated at 4 US hospitals. We calculated carrier frequencies of germline pathogenic or likely pathogenic sequence variants within 306 DDR genes, summarized by DDR pathway, and compared lethal cases against indolent cases using 2-sided Fisher’s exact tests. Secondary analysis examined if carrier frequencies differed by ancestry.

Results

Lethal cases were more likely to carry a pathogenic sequence variant in a DDR gene compared with indolent cases (18.5% vs 9.6%, P = 4.30 × 10⁻⁴), even after excluding BRCA2 (14.6% vs 9.6%, P = .04). The carrier frequency was similar among lethal cases of African (16.7% including and 15.8% excluding BRCA2) and lethal cases of European (19.3% including and 14.2% excluding BRCA2) ancestry. Three DDR pathways were statistically significantly associated with lethal disease: homologous recombination (P = .003), Fanconi anemia (P = .002), and checkpoint factor (P = .02).

Conclusions

Our findings suggest that altered DDR is an important mechanism for aggressive prostate cancer not only in men of European but also of African ancestry. Therefore, interrogation of entire DDR pathways is needed to fully characterize and better define genetic risk of lethal disease.

Registries, Databases and Repositories for Developing Artificial Intelligence in Cancer Care

Modern artificial intelligence techniques have solved some previously intractable problems and produced impressive results in selected medical domains. One of their drawbacks is that they often need very large amounts of data. Pre-existing datasets in the form of national cancer registries, image/genetic depositories and clinical datasets already exist and have been used for research. In theory, the combination of healthcare Big Data with modern, data-hungry artificial intelligence techniques should offer significant opportunities for artificial intelligence development, but this has not yet happened. Here we discuss some of the structural reasons for this, barriers preventing artificial intelligence from making full use of existing datasets, and make suggestions as to enable progress. To do this, we use the framework of the 6Vs of Big Data and the FAIR criteria for data sharing and availability (Findability, Accessibility, Interoperability, and Reuse). We share our experience in navigating these barriers through The Brain Tumour Data Accelerator, a Brain Tumour Charity-supported initiative to integrate fragmented patient data into an enriched dataset. We conclude with some comments as to the limits of such approaches.

Heuristic estimation of the α/β ratio for a cohort of Mexican patients with prostate cancer treated with external radiotherapy techniques

Background

The aim of the study was to Estimate and compare the radiobiological ratio α/β with the heuristic method for a cohort of Mexican patients with prostate cancer (PCa) who were treated with external radiotherapy (RT) techniques at three Hospital Institutions in Mexico City. With the Kaplan-Meier technique and the Cox proportional hazards model, the biochemical relapse-free survival (bRFS) is determined and characterized for cohorts of Mexican patients with PCa who received treatment with external RT. Using these clinical outcomes, the radiobiological parameter α/β is determined using the heuristic methodology of Pedicini et. al.

Materials and methods

The α/β is calculated from the survival curves for different treatment schemes implemented at three distinct hospitals. The Pedicini's techniques allow to determine the parameters α/β, k and N ₀ when treatments are not radiobiologically equivalent, therefore, are built up of a set of curved pairs for the biologically effective dose (BED) versus the ratio α/β, where the ratio is given by the intersection for each pair of curves.

Results

Six different values of α/β were found: the first α/β = 2.46 Gy, the second α/β = 3.30 Gy, the third for α/β = 3.25 Gy, the fourth α/β = 3.24 Gy, the fifth α/β = 3.38 Gy and the last α/β = 4.08 Gy. These values can be explained as follows: a) The bRFS of the schemes presents a statistical variation; b) The absorbed doses given to the patient present uncertainties on the physical dosimetry that are not on the modeling; c) Finally, in the model for the bRFS of Eq. (3), there are parameters that have to be considered, such as: the number of clonogenic tumor cells N ₀ , the overall treatment time (OTT), the kick-off time for tumor repopulation T _k and the repopulation doubling time. Therefore, the mean value to α/β for all schemes has an average value of 3.29 (± 0.52) Gy.

Conclusions

The value of α / β ¯ = 3.29   ( ± 0.52 )   Gy is determined from cohorts of Mexican patients with PC a treated with external radiotherapy using the time-dependent LQ model, which is a higher value with respect to the "dogma" value of α/β 1.5 Gy obtained with the LQ model without temporal dependence. Therefore, there is a possibility of optimizing treatments radiobiologically and improving the results of bRFS in Mexican patients with PCa treated with external radiotherapy.

Genetic Contributions to Prostate Cancer Disparities in Men of West African Descent

Prostate cancer (PCa) is the second most frequently diagnosed malignancy and the second leading cause of death in men worldwide, after adjusting for age. According to the International Agency for Research on Cancer, continents such as North America and Europe report higher incidence of PCa; however, mortality rates are highest among men of African ancestry in the western, southern, and central regions of Africa and the Caribbean. The American Cancer Society reports, African Americans (AAs), in the United States, have a 1.7 increased incidence and 2.4 times higher mortality rate, compared to European American's (EAs). Hence, early population history in west Africa and the subsequent African Diaspora may play an important role in understanding the global disproportionate burden of PCa shared among Africans and other men of African descent. Nonetheless, disparities involved in diagnosis, treatment, and survival of PCa patients has also been correlated to socioeconomic status, education and access to healthcare. Although recent studies suggest equal PCa treatments yield equal outcomes among patients, data illuminates an unsettling reality of disparities in treatment and care in both, developed and developing countries, especially for men of African descent. Yet, even after adjusting for the effects of the aforementioned factors; racial disparities in mortality rates remain significant. This suggests that molecular and genomic factors may account for much of PCa disparities.

Germline Mutations in African American Men With Prostate Cancer: Incidence, Implications and Diagnostic Disparities

Recent data suggests that African American men (AAM) with prostate cancer (PCa) exhibit genetic alterations in highly penetrant germline genes, as well as low penetrant single nucleotide polymorphisms. The importance of germline variants of uncertain significance (VUS) remain poorly elucidated and given the elevated rates of VUS in AAM compared to Caucasians with PCa, further studies are needed to facilitate potential reclassification of VUS. Ongoing efforts to include AAM in genomics research is of paramount importance in order to ensure applicability of discoveries across diverse populations and potentially reduce PCa disparities as we embark on the era of precision medicine.

Germline Predisposition to Prostate Cancer in Diverse Populations

There remains a paucity of data related to germline genetic alterations predisposing patients to prostate cancer. Recent data suggest that African American, Hispanic, and Asian and Pacific Islander men exhibit genetic alterations in both highly penetrant germline genes, including BRCA1/2, ATM, and CHEK2, and the mismatch repair genes associated with Lynch syndrome, as well as low-penetrant single-nucleotide polymorphisms. However, cohort sizes remain small in many studies limiting the ability to determine clinical significance, appropriate risk stratification, and treatment implications in these diverse populations.

Genetically Informed Prostate Cancer Screening

Prostate cancer represents a significant health care burden in the United States due to its incidence, treatment-related morbidity, and cancer-specific mortality. The burden begins with prostate-specific antigen screening, which has been subject to controversy due to concerns of overdiagnosis and overtreatment. Advancements in molecular oncology have provided evidence for the inherited predisposition to prostate cancer, which could improve individualized, risk-adapted approaches to screening and mitigate the harms of routine screening. This review presents the current evidence for the genetic basis of prostate cancer and novel genetically informed, risk-adapted screening strategies for prostate cancer.

Immune Inflammation Pathways as Therapeutic Targets to Reduce Lethal Prostate Cancer in African American Men

Despite substantial improvements in cancer survival, not all population groups have benefitted equally from this progress. For prostate cancer, men of African descent in the United States and England continue to have about double the rate of fatal disease compared to other men. Studies suggest that when there is equal access to care, survival disparities are greatly diminished. However, notable differences exist in prostate tumor biology across population groups. Ancestral factors and disparate exposures can lead to altered tumor biology, resulting in a distinct disease etiology by population group. While equal care remains the key target to improve survival, additional efforts should be made to gain comprehensive knowledge of the tumor biology in prostate cancer patients of African descent. Such an approach may identify novel intervention strategies in the era of precision medicine. A growing body of evidence shows that inflammation and the immune response may play a distinct role in prostate cancer disparities. Low-grade chronic inflammation and an inflammatory tumor microenvironment are more prevalent in African American patients and have been associated with adverse outcomes. Thus, differences in activation of immune-inflammatory pathways between African American and European American men with prostate cancer may exist. These differences may influence the response to immune therapy which is consistent with recent observations. This review will discuss mechanisms by which inflammation may contribute to the disparate outcomes experienced by African American men with prostate cancer and how these immunogenic and inflammatory vulnerabilities could be exploited to improve their survival.

Leveraging genetic ancestry to study health disparities

Research to understand human genomic variation and its implications in health has great potential to contribute in the reduction of health disparities. Biological anthropology can play important roles in genomics and health disparities research using a biocultural approach. This paper argues that racial/ethnic categories should not be used as a surrogate for sociocultural factors or global genomic clusters in biomedical research or clinical settings, because of the high genetic heterogeneity that exists within traditional racial/ethnic groups. Genetic ancestry is used to show variation in ancestral genomic contributions to recently admixed populations in the United States, such as African Americans and Hispanic/Latino Americans. Genetic ancestry estimates are also used to examine the relationship between ancestry-related biological and sociocultural factors affecting health disparities. To localize areas of genomes that contribute to health disparities, admixture mapping and genome-wide association studies (GWAS) are often used. Recent GWAS have identified many genetic variants that are highly differentiated among human populations that are associated with disease risk. Some of these are population-specific variants. Many of these variants may impact disease risk and help explain a portion of the difference in disease burden among racial/ethnic groups. Genetic ancestry is also of particular interest in precision medicine and disparities in drug efficacy and outcomes. By using genetic ancestry, we can learn about potential biological differences that may contribute to the heterogeneity observed across self-reported racial groups.

Stigma, beliefs and perceptions regarding prostate cancer among Black and Latino men and women

BACKGROUND

Health disparities in prostate cancer (PC) are thought to reflect the complex interplay of socioeconomics, environment and biology. The potential impact of beliefs and perceptions about PC among Black and Latino populations on clinical disparities are not well understood. This qualitative study was conducted to assess current prevalent and pervasive stigma, beliefs and perceptions regarding PC among Blacks and Latinos living in a large metropolitan area, thereby identifying potentially modifiable barriers to care.

METHODS

Qualitative data were collected through four separate focus groups of self-identified Black and Latino adult men and women living in Philadelphia to better understand their perceptions of PC diagnosis, screening and treatment. Each focus group was single-sex and conducted by racial/ethnic group in order to assess possible differences in beliefs about PC based on gender and racial/ethnic affiliation. Audio recordings were transcribed verbatim by trained research assistants and qualitative data analysis was conducted using modified grounded theory.

RESULTS

There were a total of 34 participants: 19 Hispanics/Latinos and 15 Blacks, with equal numbers of men and women (n=17). Median age was 57 years (range: 18 to 85 years). Dominant themes that emerged with respect to PC diagnosis included the stigma surrounding this condition and the perceived role of an "unhealthy lifestyle" and certain sexual behaviors as risk factors for PC development. While the majority of participants acknowledged the importance of PC screening and early detection, discussion centered around the barriers to both the interest in seeking medical care and the likelihood of securing it. These barriers included misunderstanding of PC etiology, distrust of the medical profession, and financial/access limitations. Men expressed substantial confusion about PC screening guidelines. In the Black female group, the role of faith and religion in the course of disease was a major theme. Both Black and Latina females discussed the role of fear and avoidance around PC screening and treatment, as well as the prevalence of misinformation about PC in their familial and social communities.

CONCLUSION

Black and Latino focus groups revealed the existence of cultural beliefs, misunderstandings and fears pertaining to PC which could influence health-related behaviors. Some themes were common across groups; others suggested racial and gender predilections. Future targeted efforts focused on directly addressing prevalent misperceptions among underserved communities in urban settings could help to improve health literacy and equity in PC outcomes in these populations.

Polygenic hazard score is associated with prostate cancer in multi-ethnic populations

Genetic models for cancer have been evaluated using almost exclusively European data, which could exacerbate health disparities. A polygenic hazard score (PHS1) is associated with age at prostate cancer diagnosis and improves screening accuracy in Europeans. Here, we evaluate performance of PHS2 (PHS1, adapted for OncoArray) in a multi-ethnic dataset of 80,491 men (49,916 cases, 30,575 controls). PHS2 is associated with age at diagnosis of any and aggressive (Gleason score ≥ 7, stage T3-T4, PSA ≥ 10 ng/mL, or nodal/distant metastasis) cancer and prostate-cancer-specific death. Associations with cancer are significant within European (n = 71,856), Asian (n = 2,382), and African (n = 6,253) genetic ancestries (p < 10-180). Comparing the 80th/20th PHS2 percentiles, hazard ratios for prostate cancer, aggressive cancer, and prostate-cancer-specific death are 5.32, 5.88, and 5.68, respectively. Within European, Asian, and African ancestries, hazard ratios for prostate cancer are: 5.54, 4.49, and 2.54, respectively. PHS2 risk-stratifies men for any, aggressive, and fatal prostate cancer in a multi-ethnic dataset.

Family history of prostate cancer and prostate tumor aggressiveness in black and non-black men;results from an equal access biopsy study

Purpose

To test for racial differences in associations between family history (FH) of prostate cancer (PC) and prostate cancer aggressiveness in a racially diverse equal access population undergoing prostate biopsy.

Subjects/patients and methods

We prospectively enrolled men undergoing prostate biopsy at the Durham Veterans Administration from 2007 to 2018 and assigned case or control status based on biopsy results. Race and FH of PC were self-reported on questionnaires. Logistic regression was used to test the association between FH and PC diagnosis overall and by tumor aggressiveness [high- (Grade Group 3–5) or low-grade (Grade Group 1–2) vs. no cancer], overall, and stratified by race. Models were adjusted for age and year of consent, race, PSA level, digital rectal exam findings, prostate volume, and previous (negative) biopsy receipt.

Results

Of 1,225 men, 323 had a FH of PC and 652 men were diagnosed with PC on biopsy. On multivariable analysis, FH was associated with increased odds of high-grade PC in black (OR 1.85, p = 0.041) and all men (OR 1.56, p = 0.057) and was unrelated to overall or low-grade PC diagnosis, overall, or stratified by race (all p ≥ 0.325). In sensitivity analyses among men without a previous biopsy, results were slightly more pronounced.

Conclusion

In this setting of equal access to care, positive FH of PC was associated with increased tumor aggressiveness in black men, but not non-black men undergoing prostate biopsy. Further research is required to tease apart the contribution of genetics from increased PC awareness potentially influencing screening and biopsy rates in men with FH.

Supplementary Information

The online version of this article (10.1007/s10552-020-01389-8) contains supplementary material, which is available to authorized users.

The Impact of African Ancestry on Prostate Cancer Disparities in the Era of Precision Medicine

Prostate cancer disproportionately affects men of African ancestry at nearly twice the rate of men of European ancestry despite the advancement of treatment strategies and prevention. In this review, we discuss the underlying causes of these disparities including genetics, environmental/behavioral, and social determinants of health while highlighting the implications and challenges that contribute to the stark underrepresentation of men of African ancestry in clinical trials and genetic research studies. Reducing prostate cancer disparities through the development of personalized medicine approaches based on genetics will require a holistic understanding of the complex interplay of non-genetic factors that disproportionately exacerbate the observed disparity between men of African and European ancestries.

Gene expression analysis reveals a pitfall in the molecular research of prostate tumors relevant to Gleason score

Gleason score (GS) is a powerful prognostic factor in prostate cancer (PCa). A GS-7 tumor typically has the primary Gleason (architectural) pattern and secondary prevalent one being graded with 3 and 4 (or 4 and 3), respectively. Due to the well-known intratumoral multifocal occurrence of different patterns, a biological sample from a GS-7 tumor used in a molecular experiment will be uncertain regarding the actually represented pattern if no special attention is given to specimen preparation. In this study, by an integrative analysis of several published gene expression datasets, one of which is the profiling of the paired GP-3 (Gleason pattern 3) and GP-4 (Gleason pattern 4) specimens of 13 GS-7 tumors, we demonstrate that such an uncertainty can be frequently observed in the published data. More specifically, our results suggest that the GS-7 specimens used to generate the frequently-cited The Cancer Genome Atlas (TCGA) data and the Gene Expression Omnibus (GEO) dataset GSE21032 which largely are individual GP-3 or GP-4 specimens rather than the "intermediate" specimens of GP-3 and GP-4. This indicates a pitfall in the existing molecular research of prostate tumors relevant to GS and in GS-related molecular biomarker identification using the previously documented data.

Comparison by Race of Conservative Management for Low-Risk and Intermediate-Risk Prostate Cancers in Veterans From 2004 to 2018

Importance

Conservative management (ie, active surveillance or watchful waiting) is a guideline-based strategy for men with low-risk and intermediate-risk prostate cancer. However, use of conservative management is controversial for African American patients, who have worse prostate cancer outcomes compared with White patients.

Objective

To examine the association of African American race with the receipt and duration of conservative management in the Veterans Health Administration (VA), a large equal-access health system.

Design, Setting, and Participants

This cohort study used data from the VA Corporate Data Warehouse for 51 543 African American and non-Hispanic White veterans diagnosed with low-risk and intermediate-risk localized node-negative prostate cancer between January 1, 2004, and December 31, 2013. Men who did not receive continuous VA care were excluded. Data were analyzed from February 1 to June 30, 2020.

Exposures

All patients received either definitive therapy (ie, prostatectomy, radiation, androgen deprivation therapy) or conservative management (ie, active surveillance or watchful waiting).

Main Outcomes and Measures

Receipt of conservative management and (for patients receiving conservative management) time from diagnosis to definitive therapy.

Results

The median (interquartile range) age of the 51 543 veterans in our cohort was 65 (61-70) years, and 14 830 veterans (28.8%) were African American individuals. Compared with White veterans, African American veterans were more likely to have intermediate-risk disease (18 988 [51.7%] vs 8526 [57.5%]), 3 or more comorbidities (15 438 [42.1%] vs 7614 [51.3%]), and high disability-related or income-related needs (9078 [24.7%] vs 4614 [31.1%]). Overall, 20 606 veterans (40.0%) received conservative management. African American veterans with low-risk disease (adjusted relative risk, 0.95; 95% CI, 0.92-0.98; P < .001) and intermediate-risk disease (adjusted relative risk, 0.92; 95% CI, 0.87-0.97; P = .002) were less likely to receive conservative management than White veterans. Compared with White veterans, African American veterans with low-risk disease (adjusted hazard ratio, 1.71; 95% CI, 1.50-1.95; P < .001) and intermediate-risk disease (adjusted hazard ratio, 1.46; 95% CI, 1.27-1.69; P < .001) who received conservative management were more likely to receive definitive therapy within 5 years of diagnosis (restricted mean survival time [SE] at 5 years, 1679 [5.3] days vs 1740 [2.4] days; P < .001).

Conclusions and Relevance

In this study, conservative management was less commonly used and less durable for African American veterans than for White veterans. Prospective trials should assess the comparative effectiveness of conservative management in African American men with prostate cancer.

Ethnic variation in prostate cancer detection: a feasibility study for use of the Stockholm3 test in a multiethnic U.S. cohort

BACKGROUND

The Stockholm3 test improves Gleason Grade Group ≥2 (GG ≥ 2) prostate cancer (PC) detection, however it has not been evaluated in an American cohort where clinical practice patterns and ethnicity differ. We aimed to identify subgroups within a Stockholm population with PC risk profiles matching American ethnicity-specific subgroups and compare the detection of PC and describe Stockholm3 performance within these subgroups.

METHODS

All men age 49-70 years presenting for prostate biopsies were evaluated at UIC from 2016 to 2019, as well as men in Stockholm from 2012 to 2014 in the STHLM3 study. Propensity scores (PS) were estimated for each person using logistic regression for age, PSA, prostate volume, family history of PC, 5-alpha reductase inhibitor use, and prior biopsy. 3:1 PS matching was performed for Stockholm to Chicago ethnicity-specific cohorts and odds ratios (OR) were computed to compare detection of GG ≥ 2 PC between groups.

RESULTS

504 Chicago men and 6980 Stockholm men were included. In African American (AA) men, 51% had GG ≥ 2 PC detected, while in risk-matched Stockholm men, 34% had GG ≥ 2 PC detected (OR: 2.1, p < 0.001). There was no statistical difference in GG ≥ 2 PC detected when matching Stockholm men to non-Hispanic Caucasian men (31% vs. 24%, OR: 0.7, p = 0.30) or Hispanic Caucasian men (31% vs. 27%, OR: 1.2, p = 0.42). The AUC for the Stockholm3 test of the matched Stockholm cohorts for AA, non-Hispanic Caucasian, and Hispanic Caucasian men was 0.85, 0.89, and 0.90, respectively.

CONCLUSIONS

Using statistical techniques to simulate a multi-ethnic Chicago cohort within the STHLM3 population, we found an excess risk of GG ≥ 2 PC among AA men. Our hypothesis that the Stockholm3 may have good predictive value in a multiethnic cohort is strengthened, and that recalibration to at least AA men seems likely to be needed to obtain well-calibrated predictions.

SEER and Gene Expression Data Analysis Deciphers Racial Disparity Patterns in Prostate Cancer Mortality and the Public Health Implication

A major racial disparity in prostate cancer (PCa) is that African American (AA) patients have a higher mortality rate than European American (EA) patients. We filtered the SEER 2009-2011 records and divided them into four groups regarding patient races and cancer grades. On such a partition, we performed a series of statistical analyses to further clarify the aforementioned disparity. Molecular evidence for a primary result of the epidemiological analysis was obtained from gene expression data. The results include: (1) Based on the registry-specific measures, a significant linear regression of total mortality rate (as well as PCa specific mortality rate) on the percentage of (Gleason pattern-based) high-grade cancers (PHG) is demonstrated in EAs (p < 0.01) but not in AAs; (2) PHG and its racial disparity are differentiated across ages and the groups defined by patient outcomes; (3) For patients with cancers in the same grade category, i.e. the high or low grade, the survival stratification between races is not significant in most geographical areas; and (4) The genes differentially expressed between AAs' and EAs' tumors of the same grade category are relatively rare. The perception that prostate tumors are more lethal in AAs than in EAs is reasonable regarding AAs' higher PHG, while high grade alone could not imply aggressiveness. However, this perception is questionable when the comparison is focused on cases within the same grade category. Supporting observations for this conclusion hold a remarkable implication for erasing racial disparity in PCa. That is, "Equal grade, equal outcomes" is not only a verifiable hypothesis but also an achievable public health goal.

Vitamin D Pathway and Other Related Polymorphisms and Risk of Prostate Cancer: Results from the Prostate Cancer Prevention Trial

Vitamin D may influence prostate cancer risk, but evidence is inconsistent. We conducted a nested case-control study in the Prostate Cancer Prevention Trial (PCPT). Cases (n = 1,128) and controls (n = 1,205) were frequency matched on age, first-degree relative with prostate cancer, and PCPT treatment arm (finasteride/placebo); African-Americans were oversampled and case/control status was biopsy confirmed. We selected 21 SNPs in vitamin D-related genes (VDR, GC, C10orf88, CYP2R1, CYP24A1, CYP27B1, DHCR7, and NADSYN1) to test genotype and genotype-treatment interactions in relation to prostate cancer. We also tested mean serum 25(OH)D differences by minor allele distributions and tested for serum 25(OH)D-genotype interactions in relation to prostate cancer risk. Log-additive genetic models (Bonferroni-corrected within genes) adjusted for age, body mass index, PSA, and family history of prostate cancer revealed a significant interaction between treatment arm and GC/rs222016 (finasteride OR = 1.37, placebo OR = 0.85; P _interaction < 0.05), GC/rs222014 (finasteride OR = 1.36, placebo OR = 0.85; P _interaction < 0.05), and CYP27B1/rs703842 (finasteride OR = 0.76, placebo OR = 1.10; P _interaction < 0.05) among Caucasians, and C10orf88/rs6599638 (finasteride OR = 4.68, placebo OR = 1.39; P _interaction < 0.05) among African-Americans. VDR/rs1544410 and CYP27B1/rs703842 had significant treatment interactions for high-grade disease among Caucasians (finasteride OR = 0.81, placebo OR = 1.40; P _interaction < 0.05 and finasteride OR = 0.70, placebo OR = 1.28; P _interaction < 0.05, respectively). Vitamin D-related SNPs influenced serum 25(OH)D, but gene-serum 25(OH)D effect modification for prostate cancer was marginally observed only for CYP24A1/rs2248359. In conclusion, evidence that vitamin D-related genes or gene-serum 25(OH)D associations influence prostate cancer risk is modest. We found some evidence for gene-finasteride interaction effects for prostate cancer in Caucasians and African-Americans. Results suggest only minimal associations of vitamin D with total or high-grade prostate cancer.

Integrative comparison of the genomic and transcriptomic landscape between prostate cancer patients of predominantly African or European genetic ancestry

Men of predominantly African Ancestry (AA) have higher prostate cancer (CaP) incidence and worse survival than men of predominantly European Ancestry (EA). While socioeconomic factors drive this disparity, genomic factors may also contribute to differences in the incidence and mortality rates. To compare the prevalence of prostate tumor genomic alterations and transcriptomic profiles by patient genetic ancestry, we evaluated genomic profiles from The Cancer Genome Atlas (TCGA) CaP cohort (n = 498). Patient global and local genetic ancestry were estimated by computational algorithms using genotyping data; 414 (83.1%) were EA, 61 (12.2%) were AA, 11 (2.2%) were East Asian Ancestry (EAA), 10 (2.0%) were Native American (NA), and 2 (0.4%) were other ancestry. Genetic ancestry was highly concordant with self-identified race/ethnicity. Subsequent analyses were limited to 61 AA and 414 EA cases. Significant differences were observed by ancestry in the frequency of SPOP mutations (20.3% AA vs. 10.0% EA; p = 5.6×10⁻⁰³), TMPRSS2-ERG fusions (29.3% AA vs. 39.6% EA; p = 4.4×10⁻⁰²), and PTEN deletions/losses (11.5% AA vs. 30.2% EA; p = 3.5×10⁻⁰³). Differentially expressed genes (DEGs) between AAs and EAs showed significant enrichment for prostate eQTL target genes (p = 8.09×10⁻⁴⁸). Enrichment of highly expressed DEGs for immune-related pathways was observed in AAs, and for PTEN/PI3K signaling in EAs. Nearly one-third of DEGs (31.3%) were long non-coding RNAs (DE-lncRNAs). The proportion of DE-lncRNAs with higher expression in AAs greatly exceeded that with lower expression in AAs (p = 1.2×10⁻¹²⁵). Both ChIP-seq and RNA-seq data suggested a stronger regulatory role for AR signaling pathways in DE-lncRNAs vs. non-DE-lncRNAs. CaP-related oncogenic lncRNAs, such as PVT1, PCAT1 and PCAT10/CTBP1-AS, were found to be more highly expressed in AAs. We report substantial heterogeneity in the prostate tumor genome and transcriptome between EA and AA. These differences may be biological contributors to racial disparities in CaP incidence and outcomes.

Disparities in cancer defined by self-identified race or ethnicity have been a long-standing and persistent challenge. It is well documented that certain racial and ethnic populations in the US experience higher incidence of specific cancer types, higher incidence of aggressive cancers, and higher mortality. The Cancer Genome Atlas (TCGA) data resource contains multi-omic profiles and clinical annotations of large-scale samples, and therefore serves as an excellent resource for the evaluation of the relationship between genetic ancestry and genomic alterations in cancers. In this study, we performed a cancer type specific analysis of the influence of genetic ancestry on genomic alterations in prostate cancers–a malignancy for which there are some of the largest cancer disparities by race and ethnicity in the US. We found that there is substantial heterogeneity in the genomic alterations and transcriptomic dysregulation occurring in men of African (AA) and European (EA) ancestry in the TCGA prostate cancer cohort. SPOP mutations, TMPRSS2-ERG fusions, PTEN deletions/losses, immune signaling, and expression of non-coding RNAs were identified as potential contributors to prostate cancer racial disparities. Our comprehensive characterization of genetic ancestry and genomic/transcriptomic alterations would provide new insight into the biology of prostate cancer racial disparities in the AA population.

TRPV6 as a Putative Genomic Susceptibility Locus Influencing Racial Disparities in Cancer

It is well established that African Americans exhibit higher incidence, higher mortality, and more aggressive forms of some cancers, including those of breast, prostate, colon, stomach, and cervix. Here we examine the ancestral haplotype of the TRPV6 calcium channel as a putative genomic factor in this racial divide. The minor (ancestral) allele frequency is 60% in people of African ancestry, but between 1% and 11% in all other populations. Research on TRPV6 structure/function, its association with specific cancers, and the evolutionary-ecological conditions that impacted selection of its haplotypes are synthesized to provide evidence for TRPV6 as a germline susceptibility locus in cancer. Recently elucidated mechanisms of TRPV6 channel deactivation are discussed in relation to the location of the allele favored in selection, suggesting a reduced capacity to inactivate the channel in those who have the ancestral haplotype. This could result in an excessively high cellular Ca²⁺, which has been implicated in cancer, for those in settings where calcium intake is far higher than in their ancestral environment. A recent report associating increasing calcium intake with a pattern of increase in aggressive prostate cancer in African-American but not European-American men may be related. If TRPV6 is found to be associated with cancer, further research would be warranted to improve risk assessment and examine interventions with the aim of improving cancer outcomes for people of African ancestry.

Adjustment strategies amongst black African and black Caribbean men following treatment for prostate cancer: Findings from the Life After Prostate Cancer Diagnosis (LAPCD) study

OBJECTIVE

To explore adjustment strategies adopted by Black African (BA) and Black Caribbean (BC) men in the UK as a response to the impact of PCa diagnosis and treatment effects.

METHODS

Men were recruited through the UK-wide 'Life After Prostate Cancer Diagnosis' (LAPCD) survey. Telephone interviews were conducted with men (n = 14) with BA and BC backgrounds between 18 and 42 months post-diagnosis. Data were analysed using a Framework approach.

RESULTS

Most men (n = 12) were born outside the UK, were married (n = 9) and employed (n = 9). Median age was 66 years (range: 55-85). Six overarching themes emerged: a strong reliance upon faith beliefs; maintaining a 'positive' front; work as distraction; non-disclosure of diagnosis even amongst family members, influenced by stigma and masculinity concerns; active awareness-raising amongst a minority and support-seeking from close community. A few men emphasised a need to 'pitch' awareness-raising messages appropriately. Potential links existed between faith beliefs, presenting a positive front, community support-seeking and local awareness-raising.

CONCLUSION

The provision of patient-centred care requires cultural sensitivity. Interventions that challenge stigma and men's reluctance to disclose problems associated with PCa and treatment may encourage help-seeking for symptom support. Research is needed to determine how best awareness-raising messages should be conveyed to black men.

Development and initial psychometric evaluation of the computer-based prostate Cancer screening decision aid acceptance scale for African-American men

BACKGROUND

To reliably evaluate the acceptance and use of computer-based prostate cancer decision aids (CBDAs) for African-American men, culturally relevant measures are needed. This study describes the development and initial psychometric evaluation of the 24-item Computer-Based Prostate Cancer Screening Decision Aid Acceptance Scale among 357 African-American men.

METHODS

Exploratory factor analysis (EFA) with maximum likelihood estimation and polychoric correlations followed by Promax and Varimax rotations.

RESULTS

EFA yielded three factors: Technology Use Expectancy and Intention (16 items), Technology Use Anxiety (5 items), and Technology Use Self-Efficacy (3 items) with good to excellent internal consistency reliability at .95, .90, and .85, respectively. The standardized root mean square residual (0.035) indicated the factor structure explained most of the correlations.

CONCLUSIONS

Findings suggest the three-factor, 24-item Computer-Based Prostate Cancer Screening Decision Aid Acceptance Scale has utility in determining the acceptance and use of CBDAs among African-American men at risk for prostate cancer. Future research is needed to confirm this factor structure among socio-demographically diverse African-Americans.

The Human TET2 Gene Contains Three Distinct Promoter Regions With Differing Tissue and Developmental Specificities

Tet methylcytosine dioxygenase 2 (TET2) is a tumor suppressor gene that is inactivated in a wide range of hematological cancers. TET2 enzymatic activity converts 5-methylcytosine (5-mC) into 5-hydroxymethylcytosine (5-hmC), an essential step in DNA demethylation. Human TET2 is highly expressed in pluripotent cells and down-regulated in differentiated cells: however, transcriptional regulation of the human TET2 gene has not been investigated in detail. Here we define three promoters within a 2.5 kb region located ∼ 87 kb upstream of the first TET2 coding exon. The three promoters, designated as Pro1, Pro2, and Pro3, generate three alternative first exons, and their presence in TET2 mRNAs varies with cell type and developmental stage. In general, all three TET2 transcripts are more highly expressed in human tissues rich in hematopoietic stem cells, such as spleen and bone marrow, compared to other tissues, such as brain and kidney. Transcripts from Pro2 are expressed by a broad range of tissues and at a significantly higher level than Pro1 or Pro3 transcripts. Pro3 transcripts were highly expressed by embryoid bodies generated from the H9 ES cell line, and the major Pro3 transcript is an alternatively spliced mRNA isoform that produces a truncated TET2 protein lacking the catalytic domain. Our study demonstrates distinct tissue-specific mechanisms of TET2 transcriptional regulation during early pluripotent states and in differentiated cell types.

Loss of LDAH associated with prostate cancer and hearing loss

Great strides in gene discovery have been made using a multitude of methods to associate phenotypes with genetic variants, but there still remains a substantial gap between observed symptoms and identified genetic defects. Herein, we use the convergence of various genetic and genomic techniques to investigate the underpinnings of a constellation of phenotypes that include prostate cancer (PCa) and sensorineural hearing loss (SNHL) in a human subject. Through interrogation of the subject's de novo, germline, balanced chromosomal translocation, we first identify a correlation between his disorders and a poorly annotated gene known as lipid droplet associated hydrolase (LDAH). Using data repositories of both germline and somatic variants, we identify convergent genomic evidence that substantiates a correlation between loss of LDAH and PCa. This correlation is validated through both in vitro and in vivo models that show loss of LDAH results in increased risk of PCa and, to a lesser extent, SNHL. By leveraging convergent evidence in emerging genomic data, we hypothesize that loss of LDAH is involved in PCa and other phenotypes observed in support of a genotype-phenotype association in an n-of-one human subject.

Epidemiology of Prostate Cancer

Prostate cancer is the second most frequent cancer diagnosis made in men and the fifth leading cause of death worldwide. Prostate cancer may be asymptomatic at the early stage and often has an indolent course that may require only active surveillance. Based on GLOBOCAN 2018 estimates, 1,276,106 new cases of prostate cancer were reported worldwide in 2018, with higher prevalence in the developed countries. Differences in the incidence rates worldwide reflect differences in the use of diagnostic testing. Prostate cancer incidence and mortality rates are strongly related to the age with the highest incidence being seen in elderly men (> 65 years of age). African-American men have the highest incidence rates and more aggressive type of prostate cancer compared to White men. There is no evidence yet on how to prevent prostate cancer; however, it is possible to lower the risk by limiting high-fat foods, increasing the intake of vegetables and fruits and performing more exercise. Screening is highly recommended at age 45 for men with familial history and African-American men. Up-to-date statistics on prostate cancer occurrence and outcomes along with a better understanding of the etiology and causative risk factors are essential for the primary prevention of this disease.

Interactions of PVT1 and CASC11 on Prostate Cancer Risk in African Americans

BACKGROUND

African American (AA) men have a higher risk of developing prostate cancer than white men. SNPs are known to play an important role in developing prostate cancer. The impact of PVT1 and its neighborhood genes (CASC11 and MYC) on prostate cancer risk are getting more attention recently. The interactions among these three genes associated with prostate cancer risk are understudied, especially for AA men. The objective of this study is to investigate SNP-SNP interactions in the CASC11-MYC-PVT1 region associated with prostate cancer risk in AA men.

METHODS

We evaluated 205 SNPs using the 2,253 prostate cancer patients and 2,423 controls and applied multiphase (discovery-validation) design. In addition to SNP individual effects, SNP-SNP interactions were evaluated using the SNP Interaction Pattern Identifier, which assesses 45 patterns.

RESULTS

Three SNPs (rs9642880, rs16902359, and rs12680047) and 79 SNP-SNP pairs were significantly associated with prostate cancer risk. These two SNPs (rs16902359 and rs9642880) in CASC11 interacted frequently with other SNPs with 56 and 9 pairs, respectively. We identified the novel interaction of CASC11-PVT1, which is the most common gene interaction (70%) in the top 79 pairs. Several top SNP interactions have a moderate to large effect size (OR, 0.27-0.68) and have a higher prediction power to prostate cancer risk than SNP individual effects.

CONCLUSIONS

Novel SNP-SNP interactions in the CASC11-MYC-PVT1 region have a larger impact than SNP individual effects on prostate cancer risk in AA men.

IMPACT

This gene-gene interaction between CASC11 and PVT1 can provide valuable information to reveal potential biological mechanisms of prostate cancer development.

The Epidemiology of Prostate Cancer

Prostate cancer is a major cause of disease and mortality among men, and each year 1.6 million men are diagnosed with and 366,000 men die of prostate cancer. In this review, we discuss the state of evidence for specific genetic, lifestyle, and dietary factors associated with prostate cancer risk. Given the biological heterogeneity of this cancer, we focus on risk factors for advanced or fatal prostate cancer. First, we provide descriptive epidemiology statistics and patterns for prostate cancer incidence and mortality around the world. This includes discussion of the impact of prostate-specific antigen screening on prostate cancer epidemiology. Next, we summarize evidence for selected risk factors for which there is strong or probable evidence of an association: genetics, obesity and weight change, physical activity, smoking, lycopene and tomatoes, fish, vitamin D and calcium, and statins. Finally, we highlight future directions for prostate cancer epidemiology research.

Analysis of Racial/Ethnic Representation in Select Basic and Applied Cancer Research Studies

Over the past decades, consistent studies have shown that race/ethnicity have a great impact on cancer incidence, survival, drug response, molecular pathways and epigenetics. Despite the influence of race/ethnicity in cancer outcomes and its impact in health care quality, a comprehensive understanding of racial/ethnic inclusion in oncological research has never been addressed. We therefore explored the racial/ethnic composition of samples/individuals included in fundamental (patient-derived oncological models, biobanks and genomics) and applied cancer research studies (clinical trials). Regarding patient-derived oncological models (n = 794), 48.3% have no records on their donor's race/ethnicity, the rest were isolated from White (37.5%), Asian (10%), African American (3.8%) and Hispanic (0.4%) donors. Biobanks (n = 8,293) hold specimens from unknown (24.56%), White (59.03%), African American (11.05%), Asian (4.12%) and other individuals (1.24%). Genomic projects (n = 6,765,447) include samples from unknown (0.6%), White (91.1%), Asian (5.6%), African American (1.7%), Hispanic (0.5%) and other populations (0.5%). Concerning clinical trials (n = 89,212), no racial/ethnic registries were found in 66.95% of participants, and records were mainly obtained from Whites (25.94%), Asians (4.97%), African Americans (1.08%), Hispanics (0.16%) and other minorities (0.9%). Thus, two tendencies were observed across oncological studies: lack of racial/ethnic information and overrepresentation of Caucasian/White samples/individuals. These results clearly indicate a need to diversify oncological studies to other populations along with novel strategies to enhanced race/ethnicity data recording and reporting.

Prostate Cancer Disparities by Race and Ethnicity: From Nucleotide to Neighborhood

Prostate cancer (CaP) incidence, morbidity, and mortality rates vary substantially by race and ethnicity, with African American men experiencing among the highest CaP rates in the world. The causes of these disparities are multifactorial and complex, and likely involve differences in access to screening and treatment, exposure to CaP risk factors, variation in genomic susceptibility, and other biological factors. To date, the proportion of CaP that can be explained by environmental exposures is small and differences in the role factors play by race or ethnicity is poorly understood. In the absence of additional data, it is likely that environmental factors do not contribute greatly to CaP disparities. In contrast, CaP has one of the highest heritabilities of all major cancers and many CaP susceptibility genes have been identified. Some CaP loci, including the risk loci found at chromosome 8q24, have consistent effects in all racial/ethnic groups studied to date. However, replication of many susceptibility loci across race or ethnicity remains limited. It is likely that inequities in health care access strongly influences CaP disparities. CaP is a disease with a complex multifactorial etiology, and therefore any approach attempting to address racial/ethnic disparities in CaP must consider the many sources that influence risk, outcomes, and disparities.

Social determinants of prostate cancer in the Caribbean: a systematic review and meta-analysis

BACKGROUND

Prostate cancer remains the leading cause of cancer deaths among Caribbean men. However, little data exists on the influence of social factors on prostate cancer in the Caribbean setting. This article supports the 2011 Rio Political Declaration on addressing health inequalities by presenting a systematic review of evidence on the role of social determinants on prostate cancer in Caribbean men. It aims to determine the distribution, by known social determinants of health, of the frequency and adverse outcomes of prostate cancer among Caribbean populations.

METHODS

Observational studies reporting an association between a social determinant and prostate cancer frequency and outcomes were sought in MEDLINE, EMBASE, SciELO, CINAHL, CUMED, LILACS, and IBECS databases. Fourteen social determinants and 7 prostate cancer endpoints were chosen, providing 98 possible relationship groups exploring the role of social determinants on prostate cancer. Observational studies with > 50 participants conducted in Caribbean territories between 2004 and 2016 were eligible. The review was conducted according to STROBE and PRISMA guidelines. Random-effects meta-analyses were performed.

RESULTS

From 843 potentially relevant citations, 13 articles from 9 studies were included. From these included studies, 24 relationships were reported looking at 11 distinct relationship groups, leaving 90 relationship groups (92% of all relationship groups) unexplored. Study heterogeneity and risk of bias restricted results to a narrative synthesis in most instances. Meta-analyses showed more diagnosed prostate cancer among men with less formal education (n = 2 studies, OR 1.60, 95%CI 1.18-2.19) and among men who were married (n = 3 studies, OR 1.54, 95%CI 1.22-1.95).

CONCLUSIONS

This review highlights limited evidence for a higher occurrence of diagnosed prostate cancer among Caribbean men with lower levels of education and among men who are married. The role of social determinants on prostate cancer among Caribbean men remains poorly understood. Improvements in study quantity and quality, and reduced variability in outcomes and reporting are needed. This report represents the current evidence, and provides a roadmap to future research priorities for a better understanding of Caribbean prostate cancer inequalities.

Prostate Cancer Genomics: Recent Advances and the Prevailing Underrepresentation from Racial and Ethnic Minorities

Prostate cancer (CaP) is the most commonly diagnosed non-cutaneous cancer and the second leading cause of male cancer deaths in the United States. Among African American (AA) men, CaP is the most prevalent malignancy, with disproportionately higher incidence and mortality rates. Even after discounting the influence of socioeconomic factors, the effect of molecular and genetic factors on racial disparity of CaP is evident. Earlier studies on the molecular basis for CaP disparity have focused on the influence of heritable mutations and single-nucleotide polymorphisms (SNPs). Most CaP susceptibility alleles identified based on genome-wide association studies (GWAS) were common, low-penetrance variants. Germline CaP-associated mutations that are highly penetrant, such as those found in HOXB13 and BRCA2, are usually rare. More recently, genomic studies enabled by Next-Gen Sequencing (NGS) technologies have focused on the identification of somatic mutations that contribute to CaP tumorigenesis. These studies confirmed the high prevalence of ERG gene fusions and PTEN deletions among Caucasian Americans and identified novel somatic alterations in SPOP and FOXA1 genes in early stages of CaP. Individuals with African ancestry and other minorities are often underrepresented in these large-scale genomic studies, which are performed primarily using tumors from men of European ancestry. The insufficient number of specimens from AA men and other minority populations, together with the heterogeneity in the molecular etiology of CaP across populations, challenge the generalizability of findings from these projects. Efforts to close this gap by sequencing larger numbers of tumor specimens from more diverse populations, although still at an early stage, have discovered distinct genomic alterations. These research findings can have a direct impact on the diagnosis of CaP, the stratification of patients for treatment, and can help to address the disparity in incidence and mortality of CaP. This review examines the progress of understanding in CaP genetics and genomics and highlight the need to increase the representation from minority populations.

Genetic risk of prostate cancer in Ugandan men

BACKGROUND

Men of African-ancestry have elevated prostate cancer (PCa) incidence and mortality compared to men of other racial groups. There is support for a genetic contribution to this disparity, with evidence of genetic heterogeneity in the underlying risk alleles between populations. Studies of PCa among African men may inform the contribution of genetic risk factors to the elevated disease burden in this population.

METHODS

We conducted an association study of >100 previously reported PCa risk alleles among 571 incidence cases and 485 controls among Uganda men. Unconditional logistic regression was used to test genetic associations and a polygenic risk score (PRS) was derived to assess the cumulative effect of the known risk alleles in association with PCa risk. In an exploratory analysis, we also tested associations of 17 125 421 genotyped and imputed markers genome-wide in association with PCa risk.

RESULTS

Of the 111 known risk loci with a frequency >1%, 75 (68%) had effects that were directionally consistent with the initial discovery population,14 (13%) of which were nominally significantly associated with PCa risk at P < 0.05. Compared to men with average risk (25^th -75^th percentile in PRS distribution), Ugandan men in the top 10% of the PRS, constructed of alleles outside of 8q24, had a 2.9-fold (95%CI: 1.75, 4.97) risk of developing PCa; risk for the top 10% increased to 4.86 (95%CI: 2.70, 8.76) with the inclusion of risk alleles at 8q24. In genome-wide association testing, the strongest associations were noted with known risk alleles located in the 8q24 region, including rs72725854 (OR = 3.37, P = 2.14 × 10^-11 ) that is limited to populations of African ancestry (6% frequency).

CONCLUSIONS

The ∼100 known PCa risk variants were shown to effectively stratify PCa risk in Ugandan men, with 10% of men having a >4-fold increase in risk. The 8q24 risk region was also found to be a major contributor to PCa risk in Ugandan men, with the African ancestry-specific risk variant rs72725854 estimated to account for 12% of PCa in this population.

The 22Rv1 prostate cancer cell line carries mixed genetic ancestry: Implications for prostate cancer health disparities research using pre-clinical models

BACKGROUND

Understanding how biological factors contribute to prostate cancer (PCa) health disparities requires mechanistic functional analysis of specific genes or pathways in pre-clinical cellular and animal models of this malignancy. The 22Rv1 human prostatic carcinoma cell line was originally derived from the parental CWR22R cell line. Although 22Rv1 has been well characterized and used in numerous mechanistic studies, no racial identifier has ever been disclosed for this cell line. In accordance with the need for racial diversity in cancer biospecimens and recent guidelines by the NIH on authentication of key biological resources, we sought to determine the ancestry of 22RV1 and authenticate previously reported racial identifications for four other PCa cell lines.

METHODS

We used 29 established Ancestry Informative Marker (AIM) single nucleotide polymorphisms (SNPs) to conduct DNA ancestry analysis and assign ancestral proportions to a panel of five PCa cell lines that included 22Rv1, PC3, DU145, MDA-PCa-2b, and RC-77T/E.

RESULTS

We found that 22Rv1 carries mixed genetic ancestry. The main ancestry proportions for this cell line were 0.41 West African (AFR) and 0.42 European (EUR). In addition, we verified the previously reported racial identifications for PC3 (0.73 EUR), DU145 (0.63 EUR), MDA-PCa-2b (0.73 AFR), and RC-77T/E (0.74 AFR) cell lines.

CONCLUSIONS

Considering the mortality disparities associated with PCa, which disproportionately affect African American men, there remains a burden on the scientific community to diversify the availability of biospecimens, including cell lines, for mechanistic studies on potential biological mediators of these disparities. This study is beneficial by identifying another PCa cell line that carries substantial AFR ancestry. This finding may also open the door to new perspectives on previously published studies using this cell line.

Analysis of Tumor Biology to Advance Cancer Health Disparity Research

Cancer mortality rates in the United States continue to decline. Reductions in tobacco use, uptake of preventive measures, adoption of early detection methods, and better treatments have resulted in improved cancer outcomes for men and women. Despite this progress, some population groups continue to experience an excessive cancer burden when compared with other population groups. One of the most prominent cancer health disparities exists in prostate cancer. Prostate cancer mortality rates are highest among men of African ancestry when compared with other men, both in the United States and globally. This disparity and other cancer health disparities are largely explained by differences in access to health care, diet, lifestyle, cultural barriers, and disparate exposures to carcinogens and pathogens. Dietary and lifestyle factors, pathogens, and ancestry-related factors can modify tumor biology and induce a more aggressive disease. There are numerous examples of how environmental exposures, like tobacco, chronic stress, or dietary factors, induce an adverse tumor biology, leading to a more aggressive disease and decreased patient survival. Because of population differences in the exposure to these risk factors, they can be the cause of cancer disparities. In this review, we will summarize recent advances in our understanding of prostate and breast cancer disparities in the United States and discuss how the analysis of tumor biology can advance health disparity research.

Tissue-based biomarkers in prostate cancer

INTRODUCTION

Prostate cancer is a heterogeneous disease. Existing risk stratification tools based on standard clinlicopathologic variables (prostate specific antigen [PSA], Gleason score, and tumor stage) provide a modest degree of predictive ability. Advances in high-throughput sequencing has led to the development of several novel tissue-based biomarkers that can improve prognostication in prostate cancer management.

AREAS COVERED

The authors review commercially-available, tissue-based biomarker assays that improve upon existing risk-stratification tools in several areas of prostate cancer management, including the appropriateness of active surveillance and aiding in decision making regarding the use of adjuvant therapy. Additionally, some of the obstacles to the widespread adoption of these biomarkers and discuss several investigational sources of new biomarkers are discussed.

EXPERT COMMENTARY

Work is ongoing to answer pertinent clinical questions in prostate cancer management including which patients should undergo biopsy, active surveillance, receive adjuvant therapy, and what systemic therapy is best in the first-line. Incorporation into novel biomarkers may allow for the incorporation of a 'personalized' approach to management. Further validation will be required and questions of cost must be considered before wide scale adoption of these biomarkers. Tumor heterogeneity may impose a ceiling on the prognostic ability of biomarkers using currently available techniques.

Associations between RNA splicing regulatory variants of stemness-related genes and racial disparities in susceptibility to prostate cancer

Evidence suggests that cells with a stemness phenotype play a pivotal role in oncogenesis, and prostate cells exhibiting this phenotype have been identified. We used two genome-wide association study (GWAS) datasets of African descendants, from the Multiethnic/Minority Cohort Study of Diet and Cancer (MEC) and the Ghana Prostate Study, and two GWAS datasets of non-Hispanic whites, from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial and the Breast and Prostate Cancer Cohort Consortium (BPC3), to analyze the associations between genetic variants of stemness-related genes and racial disparities in susceptibility to prostate cancer. We evaluated associations of single-nucleotide polymorphisms (SNPs) in 25 stemness-related genes with prostate cancer risk in 1,609 cases and 2,550 controls of non-Hispanic whites (4,934 SNPs) and 1,144 cases and 1,116 controls of African descendants (5,448 SNPs) with correction by false discovery rate ≤0.2. We identified 32 SNPs in five genes (TP63, ALDH1A1, WNT1, MET and EGFR) that were significantly associated with prostate cancer risk, of which six SNPs in three genes (TP63, ALDH1A1 and WNT1) and eight EGFR SNPs showed heterogeneity in susceptibility between these two racial groups. In addition, 13 SNPs in MET and one in ALDH1A1 were found only in African descendants. The in silico bioinformatics analyses revealed that EGFR rs2072454 and SNPs in linkage with the identified SNPs in MET and ALDH1A1 (r²  > 0.6) were predicted to regulate RNA splicing. These variants may serve as novel biomarkers for racial disparities in prostate cancer risk.