Patterns of B-cell lymphocyte expression changes in pre- and post-malignant prostate tissue are associated with prostate cancer progression

BACKROUND

Inflammation characterized by the presence of T and B cells is often observed in prostate cancer, but it is unclear how T- and B-cell levels change during carcinogenesis and whether such changes influence disease progression.

METHODS

The study used a retrospective sample of 73 prostate cancer cases (45 whites and 28 African Americans) that underwent surgery as their primary treatment and had a benign prostate biopsy at least 1 year before diagnosis. CD3+, CD4+, and CD20+ lymphocytes were quantified by immunohistochemistry in paired pre- and post-diagnostic benign prostate biopsy and tumor surgical specimens, respectively. Clusters of similar trends of expression across two different timepoints and three distinct prostate regions-benign biopsy glands (BBG), tumor-adjacent benign glands (TAG), and malignant tumor glandular (MTG) regions-were identified using Time-series Anytime Density Peaks Clustering (TADPole). A Cox proportional hazards model was used to estimate the hazard ratio (HR) of time to biochemical recurrence associated with region-specific lymphocyte counts and regional trends.

RESULTS

The risk of biochemical recurrence was significantly reduced in men with an elevated CD20+ count in TAG (HR = 0.81, p = 0.01) after adjusting for covariates. Four distinct patterns of expression change across the BBG-TAG-MTG regions were identified for each marker. For CD20+, men with low expression in BBG and higher expression in TAG compared to MTG had an adjusted HR of 3.06 (p = 0.03) compared to the reference group that had nominal differences in CD20+ expression across all three regions. The two CD3+ expression patterns that featured lower CD3+ expression in the BBG compared to the TAG and MTG regions had elevated HRs ranging from 3.03 to 4.82 but did not reach statistical significance.

CONCLUSIONS

Longitudinal and spatial expression patterns of both CD3+ and CD20+ suggest that increased expression in benign glands during prostate carcinogenesis is associated with an aggressive disease course.

Corrigendum: Sex differences in the genetics of sarcoidosis across European and African ancestry populations

[This corrects the article DOI: 10.3389/fmed.2023.1132799.].

Characterizing prostate cancer risk through multi-ancestry genome-wide discovery of 187 novel risk variants

The transferability and clinical value of genetic risk scores (GRSs) across populations remain limited due to an imbalance in genetic studies across ancestrally diverse populations. Here we conducted a multi-ancestry genome-wide association study of 156,319 prostate cancer cases and 788,443 controls of European, African, Asian and Hispanic men, reflecting a 57% increase in the number of non-European cases over previous prostate cancer genome-wide association studies. We identified 187 novel risk variants for prostate cancer, increasing the total number of risk variants to 451. An externally replicated multi-ancestry GRS was associated with risk that ranged from 1.8 (per standard deviation) in African ancestry men to 2.2 in European ancestry men. The GRS was associated with a greater risk of aggressive versus non-aggressive disease in men of African ancestry (P = 0.03). Our study presents novel prostate cancer susceptibility loci and a GRS with effective risk stratification across ancestry groups.

A flexible matching strategy for matched nested case-control studies

PURPOSE

Individual matching in case-control studies improves statistical efficiency over random selection of controls but can lead to selection bias if cases are excluded due to the lack of appropriate controls or residual confounding with less strict matching criteria. We introduce flex matching, an algorithm using multiple rounds of control selection with successively relaxed matching criteria to select controls for cases.

METHODS

We simulated exposure-disease relationships in multiple cohort data sets with a range of confounding scenarios and conducted 16,800,000 nested case-control studies, comparing random selection of controls, strict matching, and flex matching. We computed average bias and statistical efficiency in estimates of exposure-disease relationships under each matching strategy.

RESULTS

On average, flex matching produced the least biased estimates of exposure-disease associations with the smallest standard errors. Strict matching algorithms that excluded cases for whom matched controls could not be identified produced biased estimates with larger standard errors. Estimates from studies with random assignment of controls were relatively unbiased, but the standard errors were larger than from studies using flex matching.

CONCLUSIONS

Flex matching should be considered for case-control designs, especially for biomarker studies where matching on technical artifacts is necessary and maximizing efficiency is a priority.

Identification of Environmental Exposures Associated with Risk of Sarcoidosis in African Americans

Rationale: Sarcoidosis is a racially disparate granulomatous disease likely caused by environmental exposures, genes, and their interactions. Despite increased risk in African Americans, few environmental risk factor studies in this susceptible population exist. Objectives: To identify environmental exposures associated with the risk of sarcoidosis in African Americans and those that differ in effect by self-identified race and genetic ancestry. Methods: The study sample comprised 2,096 African Americans (1,205 with and 891 without sarcoidosis) compiled from three component studies. Unsupervised clustering and multiple correspondence analyses were used to identify underlying clusters of environmental exposures. Mixed-effects logistic regression was used to evaluate the association of these exposure clusters and the 51 single-component exposures with risk of sarcoidosis. A comparison case-control sample of 762 European Americans (388 with and 374 without sarcoidosis) was used to assess heterogeneity in exposure risk by race. Results: Seven exposure clusters were identified, five of which were associated with risk. The exposure cluster with the strongest risk association was composed of metals (P < 0.001), and within this cluster, exposure to aluminum had the highest risk (odds ratio, 3.30; 95% confidence interval [95% CI], 2.23-4.09; P < 0.001). This effect also differed by race (P < 0.001), with European Americans having no significant association with exposure (odds ratio, 0.86; 95% CI, 0.56-1.33). Within African Americans, the increased risk was dependent on genetic African ancestry (P = 0.047). Conclusions: Our findings support African Americans having sarcoidosis environmental exposure risk profiles that differ from those of European Americans. These differences may underlie racially disparate incidence rates that are partially explained by genetic variation differing by African ancestry.

Evaluating approaches for constructing polygenic risk scores for prostate cancer in men of African and European ancestry

Genome-wide polygenic risk scores (GW-PRSs) have been reported to have better predictive ability than PRSs based on genome-wide significance thresholds across numerous traits. We compared the predictive ability of several GW-PRS approaches to a recently developed PRS of 269 established prostate cancer-risk variants from multi-ancestry GWASs and fine-mapping studies (PRS269). GW-PRS models were trained with a large and diverse prostate cancer GWAS of 107,247 cases and 127,006 controls that we previously used to develop the multi-ancestry PRS269. Resulting models were independently tested in 1,586 cases and 1,047 controls of African ancestry from the California Uganda Study and 8,046 cases and 191,825 controls of European ancestry from the UK Biobank and further validated in 13,643 cases and 210,214 controls of European ancestry and 6,353 cases and 53,362 controls of African ancestry from the Million Veteran Program. In the testing data, the best performing GW-PRS approach had AUCs of 0.656 (95% CI = 0.635-0.677) in African and 0.844 (95% CI = 0.840-0.848) in European ancestry men and corresponding prostate cancer ORs of 1.83 (95% CI = 1.67-2.00) and 2.19 (95% CI = 2.14-2.25), respectively, for each SD unit increase in the GW-PRS. Compared to the GW-PRS, in African and European ancestry men, the PRS269 had larger or similar AUCs (AUC = 0.679, 95% CI = 0.659-0.700 and AUC = 0.845, 95% CI = 0.841-0.849, respectively) and comparable prostate cancer ORs (OR = 2.05, 95% CI = 1.87-2.26 and OR = 2.21, 95% CI = 2.16-2.26, respectively). Findings were similar in the validation studies. This investigation suggests that current GW-PRS approaches may not improve the ability to predict prostate cancer risk compared to the PRS269 developed from multi-ancestry GWASs and fine-mapping.

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.

Multiple Correspondence Analysis and HLA-Associations of Organ Involvement in a Large Cohort of African-American and European-American Patients with Sarcoidosis

Sarcoidosis is a systemic granulomatous disease with predominant pulmonary involvement and vast heterogeneity of clinical manifestations and disease outcomes. African American (AA) patients suffer greater morbidity and mortality. Using Multiple Correspondence Analysis, we identified seven clusters of organ involvement in European American (EA; n = 385) patients which were similar to those previously described in a Pan-European (GenPhenReSa) and a Spanish cohort (SARCOGEAS). In contrast, AA (n = 987) had six, less well-defined and overlapping clusters with little similarity to the cluster identified in the EA cohort evaluated at the same U.S. institutions. Association of cluster membership with two-digit HLA-DRB1 alleles demonstrated ancestry-specific patterns of association and replicated known HLA effects.These results further support the notion that genetically influenced immune risk profiles, which differ based on ancestry, play a role in phenotypic heterogeneity. Dissecting such risk profiles will move us closer to personalized medicine for this complex disease.

Evaluating Approaches for Constructing Polygenic Risk Scores for Prostate Cancer in Men of African and European Ancestry

Genome-wide polygenic risk scores (GW-PRS) have been reported to have better predictive ability than PRS based on genome-wide significance thresholds across numerous traits. We compared the predictive ability of several GW-PRS approaches to a recently developed PRS of 269 established prostate cancer risk variants from multi-ancestry GWAS and fine-mapping studies (PRS 269 ). GW-PRS models were trained using a large and diverse prostate cancer GWAS of 107,247 cases and 127,006 controls used to develop the multi-ancestry PRS 269 . Resulting models were independently tested in 1,586 cases and 1,047 controls of African ancestry from the California/Uganda Study and 8,046 cases and 191,825 controls of European ancestry from the UK Biobank and further validated in 13,643 cases and 210,214 controls of European ancestry and 6,353 cases and 53,362 controls of African ancestry from the Million Veteran Program. In the testing data, the best performing GW-PRS approach had AUCs of 0.656 (95% CI=0.635-0.677) in African and 0.844 (95% CI=0.840-0.848) in European ancestry men and corresponding prostate cancer OR of 1.83 (95% CI=1.67-2.00) and 2.19 (95% CI=2.14-2.25), respectively, for each SD unit increase in the GW-PRS. However, compared to the GW-PRS, in African and European ancestry men, the PRS 269 had larger or similar AUCs (AUC=0.679, 95% CI=0.659-0.700 and AUC=0.845, 95% CI=0.841-0.849, respectively) and comparable prostate cancer OR (OR=2.05, 95% CI=1.87-2.26 and OR=2.21, 95% CI=2.16-2.26, respectively). Findings were similar in the validation data. This investigation suggests that current GW-PRS approaches may not improve the ability to predict prostate cancer risk compared to the multi-ancestry PRS 269 constructed with fine-mapping.

Sex differences in the genetics of sarcoidosis across European and African ancestry populations

Background

Sex differences in the susceptibility of sarcoidosis are unknown. The study aims to identify sex-dependent genetic variations in two clinical sarcoidosis phenotypes: Löfgren's syndrome (LS) and non-Löfgren's syndrome (non-LS).

Methods

A meta-analysis of genome-wide association studies was conducted on Europeans and African Americans, totaling 10,103 individuals from three population-based cohorts, Sweden (n = 3,843), Germany (n = 3,342), and the United States (n = 2,918), followed by an SNP lookup in the UK Biobank (UKB, n = 387,945). A genome-wide association study based on Immunochip data consisting of 141,000 single nucleotide polymorphisms (SNPs) was conducted in the sex groups. The association test was based on logistic regression using the additive model in LS and non-LS sex groups independently. Additionally, gene-based analysis, gene expression, expression quantitative trait loci (eQTL) mapping, and pathway analysis were performed to discover functionally relevant mechanisms related to sarcoidosis and biological sex.

Results

We identified sex-dependent genetic variations in LS and non-LS sex groups. Genetic findings in LS sex groups were explicitly located in the extended Major Histocompatibility Complex (xMHC). In non-LS, genetic differences in the sex groups were primarily located in the MHC class II subregion and ANXA11. Gene-based analysis and eQTL enrichment revealed distinct sex-specific gene expression patterns in various tissues and immune cell types. In LS sex groups, a pathway map related to antigen presentation machinery by IFN-gamma. In non-LS, pathway maps related to immune response lectin-induced complement pathway in males and related to maturation and migration of dendritic cells in skin sensitization in females were identified.

Conclusion

Our findings provide new evidence for a sex bias underlying sarcoidosis genetic architecture, particularly in clinical phenotypes LS and non-LS. Biological sex likely plays a role in disease mechanisms in sarcoidosis.

Abstract 3508: Association between clonal hematopoiesis and risk of prostate cancer in a large sample of African ancestry men

Clonal hematopoiesis of indeterminate potential (CHIP) has been associated with inflammation, which is a risk factor for cancer, including prostate cancer. We previously reported weak evidence of an association between CHIP and prostate cancer risk in men of European ancestry. However, little is known for African ancestry populations. We investigated the association of age-related CHIP with overall and aggressive prostate cancer risk in a large whole-exome sequencing study of 12,049 African ancestry men, including 7,176 prostate cancer cases (of which 3,283 had aggressive disease and 1,074 had metastatic disease) and 4,873 controls. Somatic variant calling was carried out using GATK Mutect2, and only variants with minor allele frequencies (MAF) &lt;0.1% and a variant allelic fraction (VAF) &gt;5% were included. Variants with a MAF ≥0.1% in gnomAD were excluded. CHIP variants were identified from a list of pre-specified mutations in 74 genes. Associations were tested using regression models adjusting for age, sub-study, and top 10 principal components, with statistical significance tested by the likelihood ratio test and applying a Bonferroni correction to account for multiple testing. In total, 998 variants in 57 CHIP genes were identified. Consistent with previous results, we observed a strong association between CHIP and age at blood draw. CHIP genes in aggregate were not statistically significantly associated with risks of total (OR=1.12, 95% CI=0.97-1.28), aggressive (OR=1.14, 95% CI=0.92-1.43) or metastatic (OR=1.17, 95% CI=0.91-1.49) prostate cancer. We observed that carriers of variants in DNMT3A, which is the gene that harbors the most CHIP driver mutations, had a nominally elevated risk of prostate cancer compared to non-carriers (OR=1.35, 95% CI=1.08-1.68, p=0.007). Additionally, carriers of variants in EZH2, which is implicated in cancer progression, showed a suggestive association with aggressive prostate cancer (OR=7.33, 95% CI=1.01-53.21, p=0.029). After adjusting for age at blood draw, CHIP genes in aggregate were not associated with age at prostate cancer diagnosis. However, we found that EZH2 variants carriers were diagnosed 12.9 years earlier on average than non-carriers (95% CI=6.1-19.7, adjusted p=0.01). A prostate cancer polygenic risk score (PRS) constructed using 269 risk variants was not associated with CHIP carrier status in aggregate (OR=0.99, 95% CI=0.92-1.06, p=0.70) or with any individual gene (all adjusted p&gt;0.05). In summary, overall CHIP is not likely to be a risk factor of prostate cancer or aggressive disease in men of African ancestry. However, our results do confirm the association of CHIP in DNMT3A with prostate cancer risk as reported in previous studies in men of European ancestry. Future work will be needed to evaluate the biological causality of DNMT3A- and EZH2- related CHIP on prostate cancer.

Citation Format: Anqi Wang, Yili Xu, Xin Sheng, Raymond Hughley, Ben Adusei, Mohamed Jalloh, Serigne Magueye Gueye, Andrew A Adjei, James Mensah, Pedro W. Fernandez, Akin Olupelumi Adebiyi, Oseremen Inokhoife Aisuodionoe-Shadrach, Lindsay Petersen, Maureen Joffe, Jeannette T. Bensen, James L. Mohler, Jack A. Taylor, Eboneé N. Butler, Sue A. Ingles, Benjamin A. Rybicki, Janet L. Stanford, Wei Zheng, Sonja I. Berndt, Chad D. Huff, Joseph Lachance, Luc Multigner, Caroline Andrews, Timothy R. Rebbeck, Laurent Brureau, Stephen J. Chanock, Adam de Smith, Fei Chen, Burcu F. Darst, David V. Conti, Christopher A. Haiman. Association between clonal hematopoiesis and risk of prostate cancer in a large sample of African ancestry men [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3508.

Abstract 80: Change in B cell lymphocyte expression from the pre- to post-malignant prostate predicts disease aggressiveness

Background: Inflammatory cells such as tumor infiltrating lymphocytes (comprising T and B cells) are often present in prostate tissue undergoing tumorigenesis but their role in disease progression is unclear. The current study aims to characterize the expression dynamics of CD3, CD4 and CD20 lymphocytes from the pre- to post-malignant prostate environment and the association of these dynamics with aggressive prostate cancer.

Methods: The study sample included 72 prostate cancer cases (44 whites and 28 African American) that underwent surgery as their primary treatment and had a benign prostate biopsy at least one year before diagnosis and were followed for biochemical recurrence (BCR). Counts of CD3-, CD4- and CD20-positive lymphocytes were quantified by immunohistochemistry using an automated multi-image processing procedure in pre-malignant benign biopsy (BB), tumor-adjacent benign (TAB) and malignant tumor glandular (MTG) regions of prostatectomy. A cox proportional hazards model was used to estimate the hazard ratio (HR) of time to BCR associated with inflammatory marker count in different regions of the prostate. Clustering was performed to identify similar trends of expression changes of CD3, CD4 and CD20 between the regions - BB, TAG and MTG using Time-series Anytime Density Peaks Clustering (TADPole).

Results: The risk of BCR was significantly reduced in men who had an elevated CD20 count in the TAG (HR=0.80, p=0.01) after adjusting for race, age at diagnosis, PSA at the time of benign biopsy and the Gleason grade group. CD3 and CD4 counts in the prostate regions did not show any significant association to BCR. TADPole identified four main different patterns of CD20 expression changes across the BB-TAB-MTG regions namely 1) minimal to no change in expression between the regions (n=45 pairs); 2) high expression in BB/no expression in TAG/higher expression in MTG (n=3 pairs); 3) high expression in BB/higher expression in TAG/no expression in MTG (n=8 pairs); 4) no expression in BB/higher expression in TAG compared to MTG (n=16 pairs). In comparison to the reference group (Cluster 1), Cluster 4 was at 3.5 times higher risk of BCR with an adjusted HR of 3.5 (p=0.0184).

Conclusion: Elevated CD20 expression in TAG was associated with less aggressive disease. Furthermore, cases that had CD20 expression highest in their benign prostate adjacent to tumor preceded by absence of CD20 expression in their pre-malignant benign prostate had the most aggressive disease course. Further studies are warranted to understand how CD20 lymphocyte dynamic changes influence prostate tumorigenesis.

Citation Format: Sudha M. Sadasivan, Yalei Chen, Nilesh S. Gupta, Ryan Sanii, Kevin R. Bobbitt, Dhananjay A. Chitale, Sean R. Williamson, Andrew G. Rundle, Deliang Tang, Benjamin A. Rybicki. Change in B cell lymphocyte expression from the pre- to post-malignant prostate predicts disease aggressiveness [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 80.

Convolutional Neural Network Quantification of Gleason Pattern 4 and Association with Biochemical Recurrence in Intermediate Grade Prostate Tumors

Differential classification of prostate cancer (CaP) grade group (GG) 2 and 3 tumors remains challenging, likely due to the subjective quantification of percentage of Gleason pattern 4 (%GP4). Artificial intelligence assessment of %GP4 may improve its accuracy and reproducibility and provide information for prognosis prediction. To investigate this potential, a convolutional neural network (CNN) model was trained to objectively identify and quantify Gleason pattern (GP) 3 and 4 areas, estimate %GP4, and assess whether CNN-assessed %GP4 is associated with biochemical recurrence (BCR) risk in intermediate risk GG 2 and 3 tumors. The study was conducted in a radical prostatectomy cohort (1999-2012) of African American men from the Henry Ford Health System (Detroit, Michigan). A CNN model that could discriminate four tissue types (stroma, benign glands, GP3 glands, and GP4 glands) was developed using histopathologic images containing GG 1 (n=45) and 4 (n=20) tumor foci. The CNN model was applied to GG 2 (n=153) and 3 (n=62) for %GP4 estimation, and Cox proportional hazard modeling was used to assess the association of %GP4 and BCR, accounting for other clinicopathologic features including GG. The CNN model achieved an overall accuracy of 86% in distinguishing the four tissue types. Further, CNN-assessed %GP4 was significantly higher in GG 3 compared with GG 2 tumors (p=7.2*10^-11). %GP4 was associated with an increased risk of BCR (adjusted HR=1.09 per 10% increase in %GP4, p=0.010) in GG 2 and 3 tumors. Within GG 2 tumors specifically, %GP4 was more strongly associated with BCR (adjusted HR=1.12, p=0.006). Our findings demonstrate the feasibility of CNN-assessed %GP4 estimation, which is associated with BCR risk. This objective approach could be added to the standard pathological assessment for patients with GG 2 and 3 tumors and act as a surrogate for specialist genitourinary pathologist evaluation when such consultation is not available.

Developing an algorithm across integrated healthcare systems to identify a history of cancer using electronic medical records

OBJECTIVE

Tumor registries in integrated healthcare systems (IHCS) have high precision for identifying incident cancer but often miss recently diagnosed cancers or those diagnosed outside of the IHCS. We developed an algorithm using the electronic medical record (EMR) to identify people with a history of cancer not captured in the tumor registry to identify adults, aged 40-65 years, with no history of cancer.

MATERIALS AND METHODS

The algorithm was developed at Kaiser Permanente Colorado, and then applied to 7 other IHCS. We included tumor registry data, diagnosis and procedure codes, chemotherapy files, oncology encounters, and revenue data to develop the algorithm. Each IHCS adapted the algorithm to their EMR data and calculated sensitivity and specificity to evaluate the algorithm's performance after iterative chart review.

RESULTS

We included data from over 1.26 million eligible people across 8 IHCS; 55 601 (4.4%) were in a tumor registry, and 44848 (3.5%) had a reported cancer not captured in a registry. The common attributes of the final algorithm at each site were diagnosis and procedure codes. The sensitivity of the algorithm at each IHCS was 90.65%-100%, and the specificity was 87.91%-100%.

DISCUSSION

Relying only on tumor registry data would miss nearly half of the identified cancers. Our algorithm was robust and required only minor modifications to adapt to other EMR systems.

CONCLUSION

This algorithm can identify cancer cases regardless of when the diagnosis occurred and may be useful for a variety of research applications or quality improvement projects around cancer care.

Novel HLA associations with outcomes of Mycobacterium tuberculosis exposure and sarcoidosis in individuals of African ancestry using nearest-neighbor feature selection

Tuberculosis and sarcoidosis are inflammatory diseases characterized by granulomas that may occur in any organ but are often found in the lung. The panoply of classical human leukocyte antigen (HLA) alleles associated with occurrence and/or severity of both diseases varies considerably across studies. This heterogeneity of results, due to variation in factors like ancestry and disease subphenotype, as well as the use of simple modeling strategies to elucidate likely complex relationships, has made conclusions about underlying commonalities difficult. Here we perform HLA association analyses in individuals of African ancestry, using a greater resolution to include subphenotypes of disease and employing more comprehensive analytical techniques. Using a novel application of nearest-neighbor feature selection to score allelic importance, we investigated HLA allele association with Mycobacterium tuberculosis exposure outcomes in the first analysis of both latent Mycobacterium tuberculosis infection and active disease compared with those who, despite long-term exposure to active index cases, have neither positive diagnostic tests nor display clinical symptoms. We also compared persistent to resolved sarcoidosis. This led to the identification of novel HLA associations and evidence of main effects and interaction effects. We found strikingly similar main effects and interaction effects at HLA-DRB1, -DQB1, and -DPB1 in those resistant to tuberculosis (either latent or active) and persistent sarcoidosis.

Race Differences in Telomere Length in Benign Prostate Biopsies and Subsequent Risk of Prostate Cancer

BACKGROUND

Telomere shortening is linked to aging and may be associated with increased risk for cancer. Most cancer studies have used telomere length in leukocytes rather than in the target tissue of cancer origin.

METHODS

A case-control study of 524 case-control pairs with a benign prostate biopsy nested within a historical cohort of 10,478 men was conducted to determine whether premalignant prostate telomere length (assessed using a modified qRT-PCR) is associated with prostate cancer risk.

RESULTS

Telomere lengths in benign prostate biopsies of cases versus controls were similar (1.46 ± 0.38 vs. 1.45 ± 0.42; P = 0.49). African American (AA) men had significantly shorter telomeres compared with White men (1.51 ± 0.38 vs. 1.63 ± 0.39; P < 0.0001). In race-stratified analyses, increasing telomere length was more strongly associated with prostate cancer risk in White men, wherein those with telomere length in the highest quartile had 1.9-fold greater adjusted risk of prostate cancer compared with men with prostate telomere lengths in the lowest quartile [OR = 1.90; 95% confidence interval (CI) = 1.08-3.36]. Men in the highest telomere length quartile also had a greater risk of aggressive prostate cancer compared with men with telomere lengths in the lowest quartile (OR = 2.78; 95% CI = 1.25-6.19).

CONCLUSIONS

White men have longer telomeres in benign prostate tissue compared with AA men, and those with the longest telomeres may be at increased risk for prostate cancer, particularly the more aggressive form of the disease.

IMPACT

Race-specific telomere length measures may be an early biomarker of aggressive prostate cancer.

A Rare Germline HOXB13 Variant Contributes to Risk of Prostate Cancer in Men of African Ancestry

A rare African ancestry-specific germline deletion variant in HOXB13 (X285K, rs77179853) was recently reported in Martinican men with early-onset prostate cancer. Given the role of HOXB13 germline variation in prostate cancer, we investigated the association between HOXB13 X285K and prostate cancer risk in a large sample of 22 361 African ancestry men, including 11 688 prostate cancer cases. The risk allele was present only in men of West African ancestry, with an allele frequency in men that ranged from 0.40% in Ghana and 0.31% in Nigeria to 0% in Uganda and South Africa, with a range of frequencies in men with admixed African ancestry from North America and Europe (0-0.26%). HOXB13 X285K was associated with 2.4-fold increased odds of prostate cancer (95% confidence interval [CI] = 1.5-3.9, p = 2 × 10^-4), with greater risk observed for more aggressive and advanced disease (Gleason ≥8: odds ratio [OR] = 4.7, 95% CI = 2.3-9.5, p = 2 × 10^-5; stage T3/T4: OR = 4.5, 95% CI = 2.0-10.0, p = 2 × 10^-4; metastatic disease: OR = 5.1, 95% CI = 1.9-13.7, p = 0.001). We estimated that the allele arose in West Africa 1500-4600 yr ago. Further analysis is needed to understand how the HOXB13 X285K variant impacts the HOXB13 protein and function in the prostate. Understanding who carries this mutation may inform prostate cancer screening in men of West African ancestry. PATIENT SUMMARY: A rare African ancestry-specific germline deletion in HOXB13, found only in men of West African ancestry, was reported to be associated with an increased risk of overall and advanced prostate cancer. Understanding who carries this mutation may help inform screening for prostate cancer in men of West African ancestry.

Racial differences in the systemic inflammatory response to prostate cancer

Systemic inflammation may increase risk for prostate cancer progression, but the role it plays in prostate cancer susceptibility is unknown. From a cohort of over 10,000 men who had either a prostate biopsy or transurethral resection that yielded a benign finding, we analyzed 517 incident prostate cancer cases identified during follow-up and 373 controls with one or more white blood cell tests during a follow-up period between one and 18 years. Multilevel, multivariable longitudinal models were fit to two measures of systemic inflammation, neutrophil-to-lymphocyte ratio (NLR) and monocyte-to-lymphocyte ratio (MLR), to determine NLR and MLR trajectories associated with increased risk for prostate cancer. For both measures, we found no significant differences in the trajectories by case/control status, however in modeling NLR trajectories there was a significant interaction between race (white or Black and case-control status. In race specific models, NLR and MLR values were consistently higher over time among white controls than white cases while case-control differences in NLR and MLR trajectories were not apparent among Black men. When cases were classified as aggressive as compared to non-aggressive, the case-control differences in NLR and MLR values over time among white men were most apparent for non-aggressive cases. For NLR among white men, significant case-control differences were observed for the entire duration of observation for men who had inflammation in their initial prostate specimen. It is possible that, among white men, monitoring of NLR and MLR trajectories after an initial negative biopsy may be useful in monitoring prostate cancer risk.

Abstract 2100: The impact of race on the relationship between poly-CpG DNA methylation and mRNA expression in cancer with application to epigenome-wide association studies

DNA methylation is a known regulator of mRNA expression. Recent studies in cancer have shown that significant proportions of the variability in mRNA expression can be explained by variation in DNA methylation. However, none of these studies have investigated the influence of race on this relationship. Here, we develop poly-CpG site models of gene expression that facilitate the quantification of race-specific effects on the regulatory connection between methylation and transcriptional gene expression. Paired Illumina 450k methylation and RNA-Seq gene expression data from The Cancer Genome Atlas (TCGA) was used to develop poly-CpG site elastic net penalized Poisson regression models of gene expression that account for race-by-CpG interactions for each of the eight TCGA tumor types with African American (AA) representation (&gt;40 tumors each). Race-specific effects were summarized as the percentage of CpGs in a gene model with retained interaction terms. The method was applied to methylation data from an AA radical prostatectomy prostate cancer cohort (n=261) to generate predicted gene expression estimates that were used to perform a mechanistic epigenome-wide association study (EWAS) of Gleason grade (≤3+4 and ≥4+3 tumors). High percentages of variability in mRNA expression can be explained by poly-CpG site models, incorporating race specific effects, with tumor type ranges of 62-90% overall, 64-87% for AAs, and 64-92% for European Americans (EAs). Race played a significant role in the relationship between methylation and mRNA expression, with 86-97% of gene models containing at least one CpG site with a race-specific effect. Further, the median percentage of CpGs in a gene model with race-specific effects ranging from 11-18%. For these race-specific effects, the vast majority (&gt;99%) had the same direction of association between the CpG site and gene expression in both AAs and EAs but with differing magnitudes. Application of this approach identified unique methylation alterations (97%) associated with Gleason grade compared with single site and comb-p region-based

EWAS. In summary, this poly-CpG site modelling approach revealed a significant impact of race in the regulatory relationship between methylation and gene expression. The high percentage of genes -and CpG sites within those genes- demonstrating race-specific effects was a general phenomenon observed across all eight tumor types investigated. In addition to revealing this previously underappreciated contribution of race, the application of the predicted gene expression output from these poly-CpG site models to perform a gene-based EWAS of Gleason grade demonstrated that it provides a) complementary information to commonly used EWAS methods and b) direct expression-based mechanistic interpretation of findings from an AA methylation-based EWAS of prostate cancer.

Citation Format: Ian M. Loveless, Yalei Chen, Sudha Sadasivan, Indrani Datta, Nilesh Gupta, Pamela Paris, Jia Li, Benjamin A. Rybicki, Albert M. Levin. The impact of race on the relationship between poly-CpG DNA methylation and mRNA expression in cancer with application to epigenome-wide association studies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2100.

Abstract 750: Race differences in telomere length in benign prostate and subsequent risk of prostate cancer

Telomere shortening is linked to aging and thought to be associated with increased risk for cancer. Most cancer studies have used leukocyte telomere length as a surrogate measure for telomere length with few focused upon telomeres in the target tissue of cancer origin. To determine whether telomere length in pre-malignant prostate tissue is associated with subsequent prostate cancer risk, we conducted a case-control study of 530 case-control pairs matched on date, age at cohort entry, and race nested within a historical cohort of 10,478 men with a benign prostate biopsy. Overall mean telomere length assessed using modified quantitative real-time PCR was not different in benign prostate biopsies of prostate cancer cases vs. matched controls (1.65 ± 0.35 vs. 1.64 ± 0.39; p=0.41). However, race was significantly associated with telomere length with African American (AA) men having shorter telomeres in benign prostate biopsy compared with white men (1.59 ± 0.37 vs. 1.70 ± 0.37; p&lt;0.0001). In race-stratified analyses, telomere length only showed a suggestive association with prostate cancer risk in white men, wherein those with telomere length in the highest quartile had 1.5-fold greater risk of prostate cancer compared to men with prostate telomere lengths in the lowest quartile (OR=1.56; 95% CI = 0.89 - 2.73 ). In addition, white men in the highest prostate telomere length quartile had almost three-fold greater risk of aggressive prostate cancer, defined as Gleason group 3 and above, tumor stage 3 or above or PSA 20 ng/ml or higher , compared with men with telomere lengths in the lowest quartile (OR=2.73; 95% CI =1.05 - 7.15). In summary, white men have longer telomeres in benign prostate tissue compared with AA men, and those with the longest telomeres may be at increased risk for prostate cancer, particularly the more aggressive form of the disease.

Citation Format: Benjamin A. Rybicki, Sudha M. Sadasivan, Yalei Chen, Ian Loveless, Nilesh S. Gupta, Dhananjay A. Chitale, Sean R. Williamson, Andrew G. Rundle, Deliang Tang. Race differences in telomere length in benign prostate and subsequent risk of prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 750.

The interplay of growth differentiation factor 15 (GDF15) expression and M2 macrophages during prostate carcinogenesis

M2 (tumor-supportive) macrophages may upregulate growth differentiation factor 15 (GDF15), which is highly expressed in prostate tumors, but the combined utility of these markers as prognostic biomarkers are unclear. We retrospectively studied 90 prostate cancer cases that underwent radical prostatectomy as their primary treatment and were followed for biochemical recurrence (BCR). These cases also had a benign prostate biopsy at least 1 year or more before their prostate cancer surgery. Using computer algorithms to analyze digitalized immunohistochemically stained slides, GDF15 expression and the presence of M2 macrophages based on the relative density of CD204- and CD68-positive macrophages were measured in prostate: (i) benign biopsy, (ii) cancer and (iii) tumor-adjacent benign (TAB) tissue. Both M2 macrophages (P = 0.0004) and GDF15 (P < 0.0001) showed significant inter-region expression differences. Based on a Cox proportional hazards model, GDF15 expression was not associated with BCR but, in men where GDF15 expression differences between cancer and TAB were highest, the risk of BCR was significantly reduced (hazard ratio = 0.26; 95% confidence interval = 0.09-0.94). In addition, cases with high levels of M2 macrophages in prostate cancer had almost a 5-fold increased risk of BCR (P = 0.01). Expression of GDF15 in prostate TAB was associated with M2 macrophage levels in both prostate cancer and TAB and appeared to moderate M2-macrophage-associated BCR risk. In summary, the relationship of GDF15 expression and CD204-positive M2 macrophage levels is different in a prostate tumor environment compared with an earlier benign biopsy and, collectively, these markers may predict aggressive disease.

Growth and differentiation factor 15 and NF-κB expression in benign prostatic biopsies and risk of subsequent prostate cancer detection

Growth and differentiation factor 15 (GDF‐15), also known as macrophage inhibitory cytokine 1 (MIC‐1), may act as both a tumor suppressor and promotor and, by regulating NF‐κB and macrophage signaling, promote early prostate carcinogenesis. To determine whether expression of these two inflammation‐related proteins affect prostate cancer susceptibility, dual immunostaining of benign prostate biopsies for GDF‐15 and NF‐κB was done in a study of 503 case‐control pairs matched on date, age, and race, nested within a historical cohort of 10,478 men. GDF‐15 and NF‐κB expression levels were positively correlated (r = 0.39; p < 0.0001), and both were significantly lower in African American (AA) compared with White men. In adjusted models that included both markers, the odds ratio (OR) for NF‐κB expression was statistically significant, OR =0.87; p = 0.03; 95% confidence interval (CI) =0.77–0.99, while GDF‐15 expression was associated with a nominally increased risk, OR =1.06; p = 0.27; 95% CI =0.96–1.17. When modeling expression levels by quartiles, the highest quartile of NF‐κB expression was associated with almost a fifty percent reduction in prostate cancer risk (OR =0.51; p = 0.03; 95% CI =0.29–0.92). In stratified models, NF‐κB had the strongest negative association with prostate cancer in non‐aggressive cases (p = 0.03), older men (p = 0.03), and in case‐control pairs with longer follow‐up (p = 0.02). Risk associated with GDF‐15 expression was best fit using nonlinear regression modeling where both first (p = 0.02) and second (p = 0.03) order GDF‐15 risk terms were associated with significantly increased risk. This modeling approach also revealed significantly increased risk associated with GDF‐15 expression for subsamples defined by AA race, aggressive disease, younger age, and in case‐control pairs with longer follow‐up. Therefore, although positively correlated in benign prostatic biopsies, NF‐κB and GDF‐15 expression appear to exert opposite effects on risk of prostate tumor development.

Genome-Wide Association Study of Ocular Sarcoidosis Confirms HLA Associations and Implicates Barrier Function and Autoimmunity in African Americans

Purpose: Identify genes associated with ocular sarcoidosis (OS).Methods: We genotyped 1.1 million genetic variants to identify significant OS associations, defined as those that achieved p < 5 × 10-8 in a genome-wide comparison of OS cases to healthy controls in our European- or African-American cohorts (EA, AA). Potential functional roles of all associated variants were assessed.Results: Eight significant non-HLA variants were found in AA OS cases compared to healthy controls and confirmed as at least suggestive when comparing OS to non-OS cases. Seven of these were within MAGI1 and include transcription factor binding sites and expression quantitative trait loci. Our EA cohort, while showing similar effect sizes at variants within MAGI1, had no significant variants. Association analysis of HLA-DRB1 alleles confirmed association to OS in EA to *04:01.Conclusion: Our results support organ-specific genetic risk in OS in a compelling candidate, MAGI1, known to be associated with barrier function and autoimmunity.

Trans-ancestry genome-wide association meta-analysis of prostate cancer identifies new susceptibility loci and informs genetic risk prediction

Prostate cancer is a highly heritable disease with large disparities in incidence rates across ancestry populations. We conducted a multiancestry meta-analysis of prostate cancer genome-wide association studies (107,247 cases and 127,006 controls) and identified 86 new genetic risk variants independently associated with prostate cancer risk, bringing the total to 269 known risk variants. The top genetic risk score (GRS) decile was associated with odds ratios that ranged from 5.06 (95% confidence interval (CI), 4.84-5.29) for men of European ancestry to 3.74 (95% CI, 3.36-4.17) for men of African ancestry. Men of African ancestry were estimated to have a mean GRS that was 2.18-times higher (95% CI, 2.14-2.22), and men of East Asian ancestry 0.73-times lower (95% CI, 0.71-0.76), than men of European ancestry. These findings support the role of germline variation contributing to population differences in prostate cancer risk, with the GRS offering an approach for personalized risk prediction.

Abstract S09-02: Outcomes by race for cancer patients hospitalized with SARS-CoV-2 infection

Purpose: Disparities in COVID-19 outcomes have been widely reported, with disproportionate negative impacts on the African American (AA) population. The purpose of this study was to evaluate the impact of race on COVID-19 outcomes for cancer patients hospitalized in a large Michigan health care system.

Methods: A cohort of hospitalized, laboratory-confirmed SARS-CoV-2 positive patients was identified through the Henry Ford Health System Institutional COVID prospective patient registry between March 1st–May 2020. Those with a diagnosis of cancer were identified using our institutional tumor registry and electronic health record (EHR). Patient self-reported race/ethnicity data were extracted from the system’s centralized EHR, as were other demographic and clinical covariates. Racial differences in cumulative incidence of mortality and hospital discharge were tested. To further evaluate the effect of race on the mortality, Fine-Gray competing-risks model was performed with discharge alive as a competing event. A P&lt;0.05 was considered statistically significant.

Results: Out of the 204 COVID+ cancer patients hospitalized in our health care system, 69.6% were AA (N=142). AA patients were slightly younger than non-AA patients (70.35 v. 74.58, p=0.023). No difference in mean BMI was detected (30.33 AA v. 29.87 non-AA, p = 0.68). A smaller proportion of AA patients had active cancer (36.6% v. 40.3%, p = 0.73). Outcomes were generally inferior in the AA cohort, although these differences were not statistically significant. The rate of ICU admission was 41.5% in AA and 37.1% in non-AA (p=0.659). 34.5% of AA patients required intubation compared to 25.8% of non-AA patients (p=0.288). In our model, older age was the only variable that significantly increased the risk of death (standard hazard ratio SHR 1.05, p = 0.002). The risk of death was higher for AA patients (SHR 1.92, p=0.068) and males (SHR 1.62, p = 0.078) but did not meet statistical significance.

Discussion: COVID-19 outcomes were worse in the AA cancer population, but these differences did not meet statistical significance. Inferior outcomes for AA cancer patients were seen despite younger age and a smaller proportion of patients with active cancer. Our analysis focused on hospitalized patients, which would tend to select patients with similar disease severity. Notably, AA patients were significantly over-represented in our cohort (70% of hospitalizations compared to 14% of Michigan population). Our results suggest that racial disparities in outcomes for cancer patients with a SARS-CoV-2 infection may exist, but further study of larger, less selected populations is needed.

Citation Format: Steven S. Chang, Clara Hwang, Mohamed A. Elshaikh, Amy Tang, Christine M. Neslund-Dudas, Albert M. Levin, Laila M. Poisson, Benjamin A. Rybicki. Outcomes by race for cancer patients hospitalized with SARS-CoV-2 infection [abstract]. In: Proceedings of the AACR Virtual Meeting: COVID-19 and Cancer; 2020 Jul 20-22. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(18_Suppl):Abstract nr S09-02.

A Germline Variant at 8q24 Contributes to Familial Clustering of Prostate Cancer in Men of African Ancestry

Although men of African ancestry have a high risk of prostate cancer (PCa), no genes or mutations have been identified that contribute to familial clustering of PCa in this population. We investigated whether the African ancestry-specific PCa risk variant at 8q24, rs72725854, is enriched in men with a PCa family history in 9052 cases, 143 cases from high-risk families, and 8595 controls of African ancestry. We found the risk allele to be significantly associated with earlier age at diagnosis, more aggressive disease, and enriched in men with a PCa family history (32% of high-risk familial cases carried the variant vs 23% of cases without a family history and 12% of controls). For cases with two or more first-degree relatives with PCa who had at least one family member diagnosed at age <60 yr, the odds ratios for TA heterozygotes and TT homozygotes were 3.92 (95% confidence interval [CI] = 2.13-7.22) and 33.41 (95% CI = 10.86-102.84), respectively. Among men with a PCa family history, the absolute risk by age 60 yr reached 21% (95% CI = 17-25%) for TA heterozygotes and 38% (95% CI = 13-65%) for TT homozygotes. We estimate that in men of African ancestry, rs72725854 accounts for 32% of the total familial risk explained by all known PCa risk variants. PATIENT SUMMARY: We found that rs72725854, an African ancestry-specific risk variant, is more common in men with a family history of prostate cancer and in those diagnosed with prostate cancer at younger ages. Men of African ancestry may benefit from the knowledge of their carrier status for this genetic risk variant to guide decisions about prostate cancer screening.

Prostate-specific antigen testing after the US Preventive Services Task Force recommendation: a population-based analysis of electronic health data

PURPOSE

This study describes longitudinal trends in the use of prostate-specific antigen (PSA)-based testing in two geographically distinct healthcare systems following the 2011 US Preventive Services Task Force (USPSTF) recommendations against routine PSA screening.

METHODS

We analyzed population-based health claims data from 253,139 men aged 40-80 who were enrolled at two US healthcare systems. We assessed trends in the percentage of eligible men receiving ≥ 1 PSA test per year by time period (2000-2008, 2009-2011, 2012-2014), age (40-54, 55-69, 70-80), and race (white, black, other, unknown), and conducted a joinpoint regression analysis.

RESULTS

Men aged 55-69 and 70-80 years of all races had similar use of PSA testing between 2000 and 2011, ranging between 47 and 56% of eligible men by year, while only 22-26% of men aged 40-54 had a PSA test per year during this period. Overall, the percentage of men receiving at least one PSA test per year decreased by 26% between 2009-2011 and 2012-2014, with similar trends across race and age groups. PSA testing declined significantly after 2011 (annual percent change = - 11.28).

CONCLUSIONS

Following the 2011 USPSTF recommendations against routine PSA screening, declines in PSA testing were observed among men of all races and across all age groups in two large US healthcare systems.

Levels of plasma glycan-binding auto-IgG biomarkers improve the accuracy of prostate cancer diagnosis

Strategies to improve the early diagnosis of prostate cancer will provide opportunities for earlier intervention. The blood-based prostate-specific antigen (PSA) assay is widely used for prostate cancer diagnosis but specificity of the assay is not satisfactory. An algorithm based on serum levels of PSA combined with other serum biomarkers may significantly improve prostate cancer diagnosis. Plasma glycan-binding IgG/IgM studies suggested that glycan patterns differ between normal and tumor cells. We hypothesize that in prostate cancer glycoproteins or glycolipids are secreted from tumor tissues into the blood and induce auto-immunoglobulin (Ig) production. A 24-glycan microarray and a 5-glycan subarray were developed using plasma samples obtained from 35 prostate cancer patients and 54 healthy subjects to identify glycan-binding auto-IgGs. Neu5Acα2-8Neu5Acα2-8Neu5Acα (G81)-binding auto-IgG was higher in prostate cancer samples and, when levels of G81-binding auto-IgG and growth differentiation factor-15 (GDF-15 or NAG-1) were combined with levels of PSA, the prediction rate of prostate cancer increased from 78.2% to 86.2% than with PSA levels alone. The G81 glycan-binding auto-IgG fraction was isolated from plasma samples using G81 glycan-affinity chromatography and identified by N-terminal sequencing of the 50 kDa heavy chain variable region of the IgG. G81 glycan-binding 25 kDa fibroblast growth factor-1 (FGF1) fragment was also identified by N-terminal sequencing. Our results demonstrated that a multiplex diagnostic combining G81 glycan-binding auto-IgG, GDF-15/NAG-1 and PSA (≥ 2.1 ng PSA/ml for cancer) increased the specificity of prostate cancer diagnosis by 8%. The multiplex assessment could improve the early diagnosis of prostate cancer thereby allowing the prompt delivery of prostate cancer treatment.

Breast and prostate cancers harbor common somatic copy number alterations that consistently differ by race and are associated with survival

Background

Pan-cancer studies of somatic copy number alterations (SCNAs) have demonstrated common SCNA patterns across cancer types, but despite demonstrable differences in aggressiveness of some cancers by race, pan-cancer SCNA variation by race has not been explored. This study investigated a) racial differences in SCNAs in both breast and prostate cancer, b) the degree to which they are shared across cancers, and c) the impact of these shared, race-differentiated SCNAs on cancer survival.

Methods

Utilizing data from The Cancer Genome Atlas (TCGA), SCNAs were identified using GISTIC 2.0, and in each tumor type, differences in SCNA magnitude between African Americans (AA) and European Americans (EA) were tested using linear regression. Unsupervised hierarchical clustering of the copy number of genes residing in race-differentiated SCNAs shared between tumor types was used to identify SCNA-defined patient groups, and Cox proportional hazards regression was used to test for association between those groups and overall/progression-free survival (PFS).

Results

We identified SCNAs that differed by race in breast (n = 58 SCNAs; permutation p < 10^− 4) and prostate tumors (n = 78 SCNAs; permutation p = 0.006). Six race-differentiated SCNAs common to breast and prostate found at chromosomes 5q11.2-q14.1, 5q15-q21.1, 8q21.11-q21.13, 8q21.3-q24.3, 11q22.3, and 13q12.3-q21.3 had consistent differences by race across both tumor types, and all six were of higher magnitude in AAs, with the chromosome 8q regions being the only amplifications. Higher magnitude copy number differences in AAs were also identified at two of these race-differentiated SCNAs in two additional hormonally-driven tumor types: endometrial (8q21.3-q24.3 and 13q12.3-q21.3) and ovarian (13q12.3-q21.3) cancers. Race differentiated SCNA-defined patient groups were significantly associated with survival differences in both cancer types, and these groups also differentiated within triple negative breast cancers based on PFS. While the frequency of the SCNA-defined patient groups differed by race, their effects on survival did not.

Conclusions

This study identified race-differentiated SCNAs shared by two related cancers. The association of SCNA-defined patient groups with survival demonstrates the clinical significance of combinations of these race-differentiated genomic aberrations, and the higher frequency of these alterations in AA relative to EA patients may explain racial disparities in risk of aggressive breast and prostate cancer.

Abstract 3517: A germline variant at 8q24 contributes to familial clustering of prostate cancer in men of African ancestry

Germline variation at 8q24 is the strongest risk factor for prostate cancer (PCa) across all racial and ethnic populations. While most 8q24 associations have been observed across populations, rs72725854 [T risk allele frequency ~6%] is only found in men of African ancestry and is the strongest known genome-wide association signal for PCa in this population. We investigated whether the T allele of rs72725854 is associated with PCa family history and age at diagnosis, characteristics known to have a strong genetic component. Analyses were performed using a sample of 9,052 cases and 8,595 controls from the African Ancestry Prostate Cancer (AAPC) GWAS Consortium and the ELLIPSE/PRACTICAL OncoArray Consortium. Participants were unselected for PCa family history. Among cases, 23.7% carried at least one copy of the T allele versus 11.6% of controls. The OR was 2.29 (95% CI=2.10–2.49) for TA heterozygotes and 5.04 (95% CI=3.36–7.55) for TT homozygotes. The percentage of cases carrying the T allele was significantly greater for men with a PCa family history (27.4% vs. 22.7% without a family history, p=0.002) and for men diagnosed &lt;60 (28.2% vs. 21.6% if over ≥60, p=0.002). The mean age at diagnosis for men with the TT genotype was 61.1 years (sd=8.7), compared to 62.7 (sd=9.1) for TA heterozygotes and 64.3 (sd=8.9) for AA homozygotes (p=5.7E-14). Carrier frequency was highest among men with both a positive family history and an early diagnosis (30.8%). The T allele was also over-represented in cases with more advanced PCa, with carrier frequencies ranging from 26% for lethal PCa (metastatic disease, PSA&gt;100 ng/ml or death from PCa), 25.4% for high-risk disease (stage T3/T4, Gleason 8-10, or PSA=20-100 ng/ml), 24.6% for intermediate-risk disease (Gleason=7, stage T1/T2, and PSA=10-20 ng/ml), and 21.4% for low-risk disease (Gleason&lt;7, stage T1/T2, and PSA&lt;10 ng/ml) (p=0.026). We also examined whether the risk allele is over-represented in 144 men from PCa families, with multiple first- and/or second-degree relatives with PCa or men diagnosed with PCa ≤55 years old. Among affected probands, 32.7% carried the risk allele, with 3.5% being homozygous carriers. The OR for TA heterozygotes and TT homozygotes was 3.41 (95% CI=2.33–4.98) and 11.06 (95% CI=3.92–31.18), respectively. Among men without a family history, the absolute risk for PCa by age 60 for non-risk allele carriers was 4.3%, compared to 9.0% and 15.6% for TA heterozygotes and TT homozygotes, respectively. Absolute risks by age 60 were higher among men with a family history of prostate cancer, reaching 9.0% for non-risk allele carriers, compared to 20.8% and 37.7% for TA heterozygotes and TT homozygotes, respectively. Given the high PCa risk conveyed by rs72725854 and the greater frequency of the allele in men with more aggressive and lethal disease, carriers of the risk allele would benefit from earlier and more regular PSA screening.

Citation Format: Burcu F. Darst, Jeannette T. Bensen, Sue A. Ingles, Benjamin A. Rybicki, Barbara Nemesure, Esther M. John, Jay H. Fowke, Victoria L. Stevens, Sonja I. Berndt, Chad D. Huff, Jong Y. Park, Wei Zheng, Elaine A. Ostrander, Shiv Srivastava, John Carpten, Thomas A. Sellers, Maureen Sanderson, Dana C. Crawford, Olivier Cussenot, Jennifer Cullen, Rick A. Kittles, Jianfeng Xu, Zsofia Kote-Jarai, Luc Multigner, Marie-Elise Parent, Florence Menegaux, Geraldine Cancel-Tassin, Adam S. Kibel, Eric A. Klein, Phyllis J. Goodman, Jennifer J. Hu, Graham Casey, Anselm J. Hennis, Ian M. Thompson, Robin Leach, James L. Mohler, Elizabeth T. Fontham, Gary J. Smith, Jack A. Taylor, Rosalind A. Eeles, Laurent Brureau, Stephen J. Chanock, Stephen Watya, Janet L. Stanford, Diptasri Mandal, William B. Isaacs, Kathleen A. Cooney, William J. Blot, David V. Conti, Christopher A. Haiman. A germline variant at 8q24 contributes to familial clustering of prostate cancer in men of African ancestry [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3517.

Abstract PR05: A meta-analysis of genome-wide association study and eQTL analysis of multiple myeloma among African Americans

Background: Persons of African ancestry (AA) experience a 1.5-2-fold risk of multiple myeloma (MM) compared to persons of European ancestry (EA). We assembled a set of MM patients with self-reported AA in order to evaluate the contribution of genetics to etiology in this high-risk group.

Methods: Here we present the results of a meta-analysis of two GWAS in 1,813 cases and 8,871 controls of AA. We also conducted an admixture mapping scan to identify risk alleles associated with local ancestry, fine-mapped the 23 known susceptibility loci to find markers that could better capture MM risk in individuals of AA, and constructed a polygenic risk score (PRS) to assess the aggregated effect of known MM risk alleles. Finally, we conducted an eQTL analysis measuring gene expression in those genes harboring a risk variant in malignant plasma cells from 292 of the patients from a single site.

Results: In GWAS analysis, we identified two suggestive novel loci located at 9p24.3 and 9p13.1 at P&lt;1 × 10-6, but no genome-wide significant association was noted. In admixture mapping, we observed a genome-wide significant inverse association between local AA at 2p24.1-23.1 and MM risk in AA individuals. 20 of the 23 known EA risk variants showed directional consistency and 9 replicated at P&lt;0.05 in AA individuals. In eight regions, we identified markers that better capture MM risk in persons of AA. AA individuals with a PRS in the top 10% had a 1.82-fold (95%CI: 1.56, 2.11) increased MM risk compared to those with average risk (25-75%). The strongest functional association was between the risk allele for variant rs56219066 at 5q15 and lower ELL2 expression (P= 5.1 × 10–12).

Conclusion: Our study shows that common genetic variation contributes to MM risk individuals of AA.

This abstract is also being presented as Poster C040.

Citation Format: Zhaohui Du, Niels Weinhold, Gregory Chi Song, Kristen A. Rand, David J. Van Den Berg, Amie E. Hwang, Xin Sheng, Victor Hom, Sikander Ailawadhi, Ajay K. Nooka, Seema Singhal, Karen Pawlish, Edward Peters, Cathryn Bock, Ann Mohrbacher, Alexander Stram, Sonja I. Berndt, William J. Blot, Graham Casey, Victoria L. Stevens, Rick Kittles, Phyllis J. Goodman, W. Ryan Diver, Anselm Hennis, Barbara Nemesure, Eric A. Klein, Benjamin A. Rybicki, Janet L. Stanford, John S. Witte, Lisa Signorello, Esther M. John, Leslie Bernstein, Antoinette Stroup, Owen W. Stephens, Maurizio Zangari, Frits Van Rhee, Andrew Olshan, Wei Zheng, Jennifer J. Hu, Regina Ziegler, Sarah J. Nyante, Sue Ann Ingles, Michael Press, John David Carpten, Stephen Chanock, Jayesh Mehta, Graham A Colditz, Jeffrey Wolf, Thomas G. Martin, Michael Tomasson, Mark A. Fiala, Howard Terebelo, Nalini Janakiraman, Laurence Kolonel, Kenneth C. Anderson, Loic Le Marchand, Daniel Auclair, Brian C.-H. Chiu, Elad Ziv, Daniel Stram, Ravi Vij, Leon Bernal-Mizrachi, Gareth J. Morgan, Jeffrey A. Zonder, Carol Ann Huff, Sagar Lonial, Robert Z. Orlowski, David V. Conti, Christopher A. Haiman, Wendy Cozen. A meta-analysis of genome-wide association study and eQTL analysis of multiple myeloma among African Americans [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr PR05.

Abstract B066: Breast and prostate cancers harbor common somatic copy number alterations that consistently differ by race and are associated with survival

African Americans (AAs) tend to have more aggressive diseases and worse outcomes for many cancer types compared to European Americans (EAs). Large structural changes on chromosomes, such as somatic copy number alterations (SCNAs), are commonly present in many cancers and associated with clinical outcomes. While studies focusing on single tumor types have identified racial differences in SCNA frequencies and their possible association with cancer outcomes, pan-cancer race-differentiated SCNAs and their clinical implications have not been fully explored. Focusing on two of the most common hormonally driven cancers, breast cancer in women and prostate cancer in men, and using data from The Cancer Genome Atlas (TCGA), we first identified recurrent SCNAs using GISTIC2 in AAs and EAs separately within each cancer. For each GISTIC2 identified SCNA region, we calculated the magnitude deviation from the expected null value (i.e. copy number (CN) = 2) using the area under the log2(CN) (cnAUC) for each tumor. Modeling cnAUC as the outcome variable, we identified SCNAs that differed between AAs and EAs in breast cancers (n=58 SCNAs; permutation p&lt;10-4) and prostate cancers (n=78 SCNAs; permutation p=0.006). Six of nine race-differentiated SCNAs common to breast and prostate cancers had consistent magnitude differences by race across both tumor types, and all six were of higher magnitude in AAs. These six race-differentiated SCNAs were found at chromosomes 5q11.2-q14.1, 5q15-q21.1, 8q21.11-q21.13, 8q21.3-q24.3, 11q22.3, and 13q12.3-q21.3 with the chromosome 8q regions being the only amplifications. Unsupervised hierarchical clustering of the SCNAs in these six race-differentiated regions identified three patient groups in each tumor type with significant survival differences. Of particular importance, within triple negative breast cancers, these SCNA patient groups showed the most significant difference in progression-free survival (p=0.019). While there was a higher frequency of AAs among the SCNA-defined patient groups with worse survival, no significant racial difference in survival was observed within each SCNA-defined patient group. This observation supports the idea that racial disparities in breast and prostate cancer outcomes might be in part due to racial differences in tumor biology that drive structural chromosomal changes shared across these common tumor types. Our ability to derive SCNA defined patient groups associated with survival based on race-differentiated genomic aberrations demonstrates both their clinical relevance and the need to understand the biologic mechanisms that give rise to them.

Citation Format: Yalei Chen, Sudha M Sadasivan, Ruicong She, Indrani Datta, Kanika Taneja, Chitale Dhananjay, Nilesh Gupta, Melissa B Davis, Lisa A Newman, Craig G Rogers, Pamela L Paris, Jia Li, Benjamin A Rybicki, Albert M Levin. Breast and prostate cancers harbor common somatic copy number alterations that consistently differ by race and are associated with survival [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr B066.

Abstract 2337: Changes in GDF15 (growth/differentiation factor 15) expression and M2 macrophages during prostate carcinogenesis

GDF15 (growth/differentiation factor 15), also known as MIC-1 (Macrophage inhibitory cytokine 1), is a divergent member of the TGFβ superfamily of cytokines and is highly expressed in prostate tumors, but its role in prostate carcinogenesis and utility as a prognostic biomarker is unclear. We studied 91 prostate cancer cases that underwent surgery as their primary treatment and were then subsequently followed for biochemical recurrence (BCR). These cases also had a benign prostate biopsy at least one year before their prostate cancer diagnosis. In both the benign biopsy and tumor specimens, we quantified the intensity of GDF15 expression and characterized the presence of tumor associated macrophages by measuring the density of CD68-positive stained cells, and the M2 macrophage marker CD204 by immunohistochemical analysis. Marker expression was measured in prostate a) benign biopsy (BS), b) tumor-adjacent benign (BGS) and c) tumor tissue (MGS) using an automated multi-image processing macro developed in the ImageJ software. A Cox proportional hazards model was used to test the association of time to BCR of the low expression group compared with medium or high biomarker expression. The risk of BCR differed with the extent of GDF15 expression in the prostatic epithelial tissue of benign and tumor regions of the prostate. For instance, in BGS, high expression of GDF15 was associated with increased risk of BCR (hazard ratio (HR)=2.58, p=0.07). After controlling for PSA at diagnosis, Gleason grade and pathologic stage, high expression of GDF15 in BGS had a stronger association with BCR (HR=3.30, p=0.04). The risk of BCR increased with increasing level of infiltration of CD204/CD68 positive macrophages in BGS (HR=4.19, p=0.02) and MGS (HR=4.16, p=0.01) even after controlling for PSA at diagnosis, Gleason grade and pathologic stage. The combined expression levels of GDF15 and CD204/CD68 showed that prostate cancer cases with small GDF15 expression changes between BGS and MGS and high CD204/CD68 expression in BGS were at 3-fold higher risk of BCR (HR=3.67, p=0.05). In summary, expression levels of GDF15 and CD204 M2 macrophages in different regions of the prostate can change as the disease progresses from benign to a tumorigenic state and serve as markers for aggressive disease. Further evaluation of these dynamic differences in the prostate immune cellular profile in the pre-malignant and malignant state may offer additional insight into inflammatory-mediated prostate carcinogenesis.

Citation Format: Sudha M. Sadasivan, Yalei Chen, Nilesh Gupta, Sean Williamson, Dhananjay Chitale, Xiaoxia Han, Kevin Bobbitt, Andrew Rundle, Deliang Tang, Benjamin A. Rybicki. Changes in GDF15 (growth/differentiation factor 15) expression and M2 macrophages during prostate carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2337.

Potential effect of anti-inflammatory drug use on PSA kinetics and subsequent prostate cancer diagnosis: Risk stratification in black and white men with benign prostate biopsy

BACKGROUND

Rising prostate-specific antigen (PSA) levels are associated with both increased risk of prostate cancer and prostatic inflammation. The confounding effects of inflammation on the utility of PSA kinetics to predict prostate cancer may be partially mitigated by anti-inflammatory drug use. We investigated the influence of anti-inflammatory drug use on the association of PSA kinetics with prostate cancer risk.

METHODS

We studied 488 prostate cancer case-control pairs (290 white, 198 African American (AA)) nested in a retrospective cohort of men with a benign prostate biopsy. A series of multivariable models estimated prostate cancer risk associated with PSA velocity (PSAV) at different levels of anti-inflammatory drug use while adjusting for the presence of both clinical and histologic prostatitis.

RESULTS

In men with one, two, or three or more courses of anti-inflammatory drug use, for each ng/mL/year increase in PSAV, prostate cancer risk increased 1.21-fold, 1.83-fold, and 1.97-fold, respectively ( P < 0.0001). In controls with histologic prostatitis, anti-inflammatory drug use was associated with a significantly lower PSAV ( P < 0.0001). This association was not observed in men with histologic prostatitis who were subsequently diagnosed with prostate cancer. A positive interaction between anti-inflammatory drug use and PSAV-associated prostate cancer risk was only observed in AA men, as well as a strong positive association between any anti-inflammatory drug use and clinical prostatitis ( P = 0.004).

CONCLUSIONS

In men with benign prostate biopsy, accounting for the presence of histologic prostatitis and anti-inflammatory drug use, particularly in AA men, may help distinguish between men with rising PSA because of prostatitis vs undiagnosed cancer.

Extended methods for gene-environment-wide interaction scans in studies of admixed individuals with varying degrees of relationships

The etiology of many complex diseases involves both environmental exposures and inherited genetic predisposition as well as interactions between them. Gene-environment-wide interaction studies (GEWIS) provide a means to identify the interactions between genetic variation and environmental exposures that underlie disease risk. However, current GEWIS methods lack the capability to adjust for the potentially complex correlations in studies with varying degrees of relationships (both known and unknown) among individuals in admixed populations. We developed novel generalized estimating equation (GEE) based methods-GEE-adaptive and GEE-joint-to account for phenotypic correlations due to kinship while accounting for covariates, including, measures of genome-wide ancestry. In simulation studies of admixed individuals, both methods controlled family-wise error rates, an advantage over the case-only approach. They demonstrated higher power than traditional case-control methods across a wide range of underlying alternative hypotheses, especially where both marginal and interaction effects were present. We applied the proposed method to conduct a GEWIS of a known sarcoidosis risk factor (insecticide exposure) and risk of sarcoidosis in African Americans and identified two novel loci with suggestive evidence of G × E interaction.

Abstract 4231: Breast and prostate cancers harbor common somatic copy number alterations that consistently differ by race-ethnicity

Pan-cancer studies of somatic copy number alterations (SCNAs) have demonstrated shared SCNAs across cancer types, but whether these shared SCNAs vary by race-ethnicity has not been explored. Utilizing data from The Cancer Genome Atlas (TCGA), we identified SCNAs in breast and prostate tumors, two cancers with racially-disparate outcomes, and then tested for differences in SCNA magnitude by self-reported African American and European American race-ethnicity, as well as by regional chromosomal African ancestry within African Americans. GISTIC2 was applied to high density SNP array data to map SCNA regions in 712 European and 174 African American female breast tumors and 267 European and 42 African American prostate tumors derived from the TCGA dataset. For each tumor, SCNA magnitude was quantified by the area under the logarithm-base 2 copy number curve, and the germline ancestral origin of SCNAs was inferred using RFMix. A linear model was used to assess the association between SCNA magnitude and race-ethnicity (or regional African ancestry) while adjusting age-at-diagnosis and tumor severity. Race-differentiated SCNAs common to breast and prostate were found at chromosomes 5q11-21, 6q12-14, 6q16-22, 8q21-24, 11q22, 13q12-21, and 16q21-24, with 8q21-24 being the only amplification. African American breast and prostate tumors had higher magnitude alterations in the regions on 5q11-21, 8q21-24, 11q22, and 13q12-21, and among African Americans, this higher magnitude at 8q21-24 and 13q12-21 was consistent with increasing regional African ancestry. Within these regions with higher magnitude SCNAs in African Americans, expression analysis revealed 18 cancer genes, including RB1 and PVT1, differentially expressed by race-ethnicity in both tumors types that were consistent with the observed SCNA differences. While differences in SCNAs by race-ethnicity have been studied in single cancers, this is the first study to identify race-differentiated SCNAs shared by two hormonally-driven cancers and to explore the potential of germline genetic ancestry as a mechanism leading to this differentiation. The differentially expressed genes within SCNAs common to both tumor types could provide further insight into the racially disparate outcomes in breast and prostate cancers.

Citation Format: Yalei Chen, Jia Li, Sudha Sadasivan, Ruicong She, Indrani Datta, Dhananjay Chitale, Nilesh Gupta, Melissa B. Davis, Craig G. Rogers, Lisa A. Newman, Pamela L. Paris, Benjamin A. Rybicki, Albert M. Levin. Breast and prostate cancers harbor common somatic copy number alterations that consistently differ by race-ethnicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4231.

Abstract 4211: The role of GDF15 (growth/differentiation factor 15) during prostate carcinogenesis

GDF15 (growth/differentiation factor 15), also known as MIC-1 (Macrophage inhibitory cytokine 1), is a divergent member of the TGFβ superfamily of cytokines and is highly expressed in prostate tumors, but its role in prostate carcinogenesis and utility as a prognostic biomarker is unclear. We studied 91 prostate cancer cases that underwent surgery as their primary treatment and were then subsequently followed for biochemical recurrence (BCR). These cases also had a benign prostate biopsy at least one year before their prostate cancer diagnosis. In both the benign biopsy and tumor specimens, we quantified the intensity of GDF15 expression and characterized the presence of tumor associated macrophages by measuring the density of CD68-positive stained cells and the M2 macrophage marker CD204 by immunohistochemical analysis. Marker expression was measured in a) benign biopsy, b) tumor-adjacent benign and c) tumor tissue using an automated multi-image processing macro developed in the ImageJ software. Expression measurements were log2 transformed and high-low cut-off points were selected that optimized the association of biomarker expression with BCR-free survival. A Cox proportional hazards model was used to test the association of time to BCR with low vs high biomarker expression. During follow-up, 23 cases (25.2%) experienced BCR (96% of men without BCR had at least one year of follow-up). An increased hazard ratio (HR) for BCR was found in men with a higher ratio of GDF15 expression in their tumor vs. tumor-adjacent benign tissue (HR: 3.74; 95% confidence interval (CI) = 1.27-10.99) Adjusting for tumor grade, pathological tumor stage and PSA at diagnosis did not alter risk estimates significantly. In these same prostate tumor specimens, increased hazard ratios for BCR were found among men who had elevated CD204 expression in tumor (HR = 5.24; 95% CI = 2.02-13.62) and in tumor-adjacent benign tissue (HR = 3.29; 95% CI = 1.32, 8.23). We found no association of BCR-free survival with either GDF15 or CD204 expression in pre-diagnostic benign biopsies. Our results suggest that men who have a larger difference in GDF15 expression levels between prostate tumor and tumor-adjacent benign tissue, and with increased levels of M2 macrophages in both tumor and tumor-adjacent benign tissue, are at greater risk of disease recurrence. Further evaluation of the differences in the prostate immune cellular profile in the pre-malignant and malignant state may offer additional insight into inflammatory-mediated prostate carcinogenesis.

Citation Format: Sudha M. Sadasivan, Yalei Chen, Nilesh S. Gupta, Kanika Taneja, Scott A. Maresh, Alysa Gonzalez, Xiaoxia Han, Kuan-Han Hank Wu, Dhananjay Chitale, Andrew Rundle, Deliang Tang, Benjamin A. Rybicki. The role of GDF15 (growth/differentiation factor 15) during prostate carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4211.

Association between cadmium and androgen receptor protein expression differs in prostate tumors of African American and European American men

Cadmium is a known carcinogen that has been implicated in prostate cancer, but how it affects prostate carcinogenesis in humans remains unclear. Evidence from basic science suggests that cadmium can bind to the androgen receptor causing endocrine disruption. The androgen receptor is required for normal prostate development and is the key driver of prostate cancer progression. In this study, we examined the association between cadmium content and androgen receptor protein expression in prostate cancer tissue of African American (N = 22) and European American (N = 30) men. Although neither overall tumor cadmium content (log transformed) nor androgen receptor protein expression level differed by race, we observed a race-cadmium interaction with regard to androgen receptor expression (P = 0.003) even after accounting for age at prostatectomy, smoking history, and Gleason score. African American men had a significant positive correlation between tumor tissue cadmium content and androgen receptor expression (Pearson correlation = 0.52, P = 0.013), while European Americans showed a non-significant negative correlation between the two (Pearson correlation = -0.19, P = 0.31). These results were unchanged after further accounting for tissue zinc content or dietary zinc or selenium intake. African American cases with high-cadmium content (>median) in tumor tissue had more than double the androgen receptor expression (0.021 vs. 0.008, P = 0.014) of African American men with low-cadmium level. No difference in androgen receptor expression was observed in European Americans by cadmium level (high 0.015 vs. low 0.011, P = 0.30). Larger studies are needed to confirm these results and if upheld, determine the biologic mechanism by which cadmium increases androgen receptor protein expression in a race-dependent manner. Our results suggest that cadmium may play a role in race disparities observed in prostate cancer.

Two Novel Susceptibility Loci for Prostate Cancer in Men of African Ancestry

Prostate cancer incidence is 1.6-fold higher in African Americans than in other populations. The risk factors that drive this disparity are unknown and potentially consist of social, environmental, and genetic influences. To investigate the genetic basis of prostate cancer in men of African ancestry, we performed a genome-wide association meta-analysis using two-sided statistical tests in 10 202 case subjects and 10 810 control subjects. We identified novel signals on chromosomes 13q34 and 22q12, with the risk-associated alleles found only in men of African ancestry (13q34: rs75823044, risk allele frequency = 2.2%, odds ratio [OR] = 1.55, 95% confidence interval [CI] = 1.37 to 1.76, P = 6.10 × 10-12; 22q12.1: rs78554043, risk allele frequency = 1.5%, OR = 1.62, 95% CI = 1.39 to 1.89, P = 7.50 × 10-10). At 13q34, the signal is located 5' of the gene IRS2 and 3' of a long noncoding RNA, while at 22q12 the candidate functional allele is a missense variant in the CHEK2 gene. These findings provide further support for the role of ancestry-specific germline variation in contributing to population differences in prostate cancer risk.

High-Density Genetic Mapping Identifies New Susceptibility Variants in Sarcoidosis Phenotypes and Shows Genomic-driven Phenotypic Differences

RATIONALE

Sarcoidosis is a multisystem disease of unknown cause. Löfgren's syndrome (LS) is a characteristic subgroup of sarcoidosis that is associated with a good prognosis in sarcoidosis. However, little is known about its genetic architecture or its broader phenotype, non-LS sarcoidosis.

OBJECTIVES

To address the genetic architecture of sarcoidosis phenotypes, LS and non-LS.

METHODS

An association study in a white Swedish cohort of 384 LS, 664 non-LS, and 2,086 control subjects, totaling 3,134 subjects using a fine-mapping genotyping platform was conducted. Replication was performed in four independent cohorts, three of white European descent (Germany, n = 4,975; the Netherlands, n = 613; and Czech Republic, n = 521), and one of black African descent (United States, n = 1,657), totaling 7,766 subjects.

MEASUREMENTS AND MAIN RESULTS

A total of 727 LS-associated variants expanding throughout the extended major histocompatibility complex (MHC) region and 68 non-LS-associated variants located in the MHC class II region were identified and confirmed. A shared overlap between LS and non-LS defined by 17 variants located in the MHC class II region was found. Outside the MHC region, two LS-associated loci, in ADCY3 and between CSMD1 and MCPH1, were observed and replicated.

CONCLUSIONS

Comprehensive and integrative analyses of genetics, transcription, and pathway modeling on LS and non-LS indicates that these sarcoidosis phenotypes have different genetic susceptibility, genomic distributions, and cellular activities, suggesting distinct molecular mechanisms in pathways related to immune response with a common region.

Larger men have larger prostates: Detection bias in epidemiologic studies of obesity and prostate cancer risk

BACKGROUND

Obesity is associated with risk of aggressive prostate cancer (PCa), but not with over-all PCa risk. However, obese men have larger prostates which may lower biopsy accuracy and cause a systematic bias toward the null in epidemiologic studies of over-all risk.

METHODS

Within a cohort of 6692 men followed-up after a biopsy or transurethral resection of the prostate (TURP) with benign findings, a nested case-control study was conducted of 495 prostate cancer cases and controls matched on age, race, follow-up duration, biopsy versus TURP, and procedure date. Data on body mass index and prostate volume at the time of the initial procedure were abstracted from medical records.

RESULTS

Prior to consideration of differences in prostate volume, overweight (OR = 1.41; 95%CI 1.01, 1.97), and obese status (OR = 1.59; 95%CI 1.09, 2.33) at the time of the original benign biopsy or TURP were associated with PCa incidence during follow-up. Prostate volume did not significantly moderate the association between body-size and PCa, however it did act as an inverse confounder; adjustment for prostate volume increased the effect size for overweight by 22% (adjusted OR = 1.52; 95%CI 1.08, 2.14) and for obese status by 23% (adjusted OR = 1.77; 95%CI 1.20, 2.62). Larger prostate volume at the time of the original benign biopsy or TURP was inversely associated with PCa incidence during follow-up (OR = 0.92 per 10 cc difference in volume; 95%CI 0.88, 0.97). In analyses that stratified case-control pairs by tumor aggressiveness of the case, prostate volume acted as an inverse confounder in analyses of non-aggressive PCa but not in analyses of aggressive PCa.

CONCLUSIONS

In studies of obesity and PCa, differences in prostate volume cause a bias toward the null, particularly in analyses of non-aggressive PCa. A pervasive underestimation of the association between obesity and overall PCa risk may exist in the literature.

Discovery and fine-mapping of adiposity loci using high density imputation of genome-wide association studies in individuals of African ancestry: African Ancestry Anthropometry Genetics Consortium

Genome-wide association studies (GWAS) have identified >300 loci associated with measures of adiposity including body mass index (BMI) and waist-to-hip ratio (adjusted for BMI, WHR_adjBMI), but few have been identified through screening of the African ancestry genomes. We performed large scale meta-analyses and replications in up to 52,895 individuals for BMI and up to 23,095 individuals for WHR_adjBMI from the African Ancestry Anthropometry Genetics Consortium (AAAGC) using 1000 Genomes phase 1 imputed GWAS to improve coverage of both common and low frequency variants in the low linkage disequilibrium African ancestry genomes. In the sex-combined analyses, we identified one novel locus (TCF7L2/HABP2) for WHR_adjBMI and eight previously established loci at P < 5×10⁻⁸: seven for BMI, and one for WHR_adjBMI in African ancestry individuals. An additional novel locus (SPRYD7/DLEU2) was identified for WHR_adjBMI when combined with European GWAS. In the sex-stratified analyses, we identified three novel loci for BMI (INTS10/LPL and MLC1 in men, IRX4/IRX2 in women) and four for WHR_adjBMI (SSX2IP, CASC8, PDE3B and ZDHHC1/HSD11B2 in women) in individuals of African ancestry or both African and European ancestry. For four of the novel variants, the minor allele frequency was low (<5%). In the trans-ethnic fine mapping of 47 BMI loci and 27 WHR_adjBMI loci that were locus-wide significant (P < 0.05 adjusted for effective number of variants per locus) from the African ancestry sex-combined and sex-stratified analyses, 26 BMI loci and 17 WHR_adjBMI loci contained ≤ 20 variants in the credible sets that jointly account for 99% posterior probability of driving the associations. The lead variants in 13 of these loci had a high probability of being causal. As compared to our previous HapMap imputed GWAS for BMI and WHR_adjBMI including up to 71,412 and 27,350 African ancestry individuals, respectively, our results suggest that 1000 Genomes imputation showed modest improvement in identifying GWAS loci including low frequency variants. Trans-ethnic meta-analyses further improved fine mapping of putative causal variants in loci shared between the African and European ancestry populations.

Genome-wide association studies (GWAS) have identified >300 genetic regions that influence body size and shape as measured by body mass index (BMI) and waist-to-hip ratio (WHR), respectively, but few have been identified in populations of African ancestry. We conducted large scale high coverage GWAS and replication of these traits in 52,895 and 23,095 individuals of African ancestry, respectively, followed by additional replication in European populations. We identified 10 genome-wide significant loci in all individuals, and an additional seven loci by analyzing men and women separately. We combined African and European ancestry GWAS and were able to narrow down 43 out of 74 African ancestry associated genetic regions to contain small number of putative causal variants. Our results highlight the improvement of applying high density genome coverage and combining multiple ancestries in the identification and refinement of location of genetic regions associated with adiposity traits.

A Meta-analysis of Multiple Myeloma Risk Regions in African and European Ancestry Populations Identifies Putatively Functional Loci

BACKGROUND

Genome-wide association studies (GWAS) in European populations have identified genetic risk variants associated with multiple myeloma.

METHODS

We performed association testing of common variation in eight regions in 1,318 patients with multiple myeloma and 1,480 controls of European ancestry and 1,305 patients with multiple myeloma and 7,078 controls of African ancestry and conducted a meta-analysis to localize the signals, with epigenetic annotation used to predict functionality.

RESULTS

We found that variants in 7p15.3, 17p11.2, 22q13.1 were statistically significantly (P < 0.05) associated with multiple myeloma risk in persons of African ancestry and persons of European ancestry, and the variant in 3p22.1 was associated in European ancestry only. In a combined African ancestry-European ancestry meta-analysis, variation in five regions (2p23.3, 3p22.1, 7p15.3, 17p11.2, 22q13.1) was statistically significantly associated with multiple myeloma risk. In 3p22.1, the correlated variants clustered within the gene body of ULK4 Correlated variants in 7p15.3 clustered around an enhancer at the 3' end of the CDCA7L transcription termination site. A missense variant at 17p11.2 (rs34562254, Pro251Leu, OR, 1.32; P = 2.93 × 10-7) in TNFRSF13B encodes a lymphocyte-specific protein in the TNF receptor family that interacts with the NF-κB pathway. SNPs correlated with the index signal in 22q13.1 cluster around the promoter and enhancer regions of CBX7 CONCLUSIONS: We found that reported multiple myeloma susceptibility regions contain risk variants important across populations, supporting the use of multiple racial/ethnic groups with different underlying genetic architecture to enhance the localization and identification of putatively functional alleles.

IMPACT

A subset of reported risk loci for multiple myeloma has consistent effects across populations and is likely to be functional. Cancer Epidemiol Biomarkers Prev; 25(12); 1609-18. ©2016 AACR.

Abstract 2635: Methylation in benign prostate and risk of disease progression in men subsequently diagnosed with prostate cancer

In DNA from prostate cancer tumors, methylation patterns in gene promoter regions can be a biomarker for disease progression. It remains unclear whether methylation patterns in benign prostate tissue—prior to malignant transformation—may provide similar prognostic information. To determine whether early methylation events predict prostate cancer outcomes, we evaluated histologically benign prostate specimens from 353 men who eventually developed prostate cancer and received “definitive” treatment (radical prostatectomy [58%] or radiation therapy [42%]). Cases were drawn from a large hospital-based cohort of men with benign prostate biopsy specimens collected between 1990 and 2002. Risk of disease progression associated with methylation was estimated using time-to-event analyses. Average follow-up was over 5 years; biochemical recurrence (BCR) occurred in 91 cases (26%). In White men, methylation of the APC gene was associated with increased risk of BCR, even after adjusting for standard clinical risk factors for prostate cancer progression (adjusted hazard ratio (aHR) = 2.26; 95%CI 1.23-4.16). APC methylation was most strongly associated with a significant increased risk of BCR in White men with low prostate specific antigen at cohort entry (HR = 3.66; 95%CI 1.51-8.85). In additional stratified analyses, we found that methylation of the RARB gene significantly increased risk of BCR in African American cases who demonstrated methylation of at least one of the other four genes under study (HR = 3.80; 95%CI 1.07-13.53). These findings may have implications in the early identification of aggressive prostate cancer as well as reducing unnecessary medical procedures and emotional distress for men who present with markers of indolent disease.

Citation Format: Benjamin A. Rybicki, Andrew Rundle, Oleksandr Kryvenko, Dhananjay Chitale, Steven Belinsky, Deliang Tang. Methylation in benign prostate and risk of disease progression in men subsequently diagnosed with prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2635.

Atlas of prostate cancer heritability in European and African-American men pinpoints tissue-specific regulation

Although genome-wide association studies have identified over 100 risk loci that explain ∼33% of familial risk for prostate cancer (PrCa), their functional effects on risk remain largely unknown. Here we use genotype data from 59,089 men of European and African American ancestries combined with cell-type-specific epigenetic data to build a genomic atlas of single-nucleotide polymorphism (SNP) heritability in PrCa. We find significant differences in heritability between variants in prostate-relevant epigenetic marks defined in normal versus tumour tissue as well as between tissue and cell lines. The majority of SNP heritability lies in regions marked by H3k27 acetylation in prostate adenoc7arcinoma cell line (LNCaP) or by DNaseI hypersensitive sites in cancer cell lines. We find a high degree of similarity between European and African American ancestries suggesting a similar genetic architecture from common variation underlying PrCa risk. Our findings showcase the power of integrating functional annotation with genetic data to understand the genetic basis of PrCa.

Methylation in benign prostate and risk of disease progression in men subsequently diagnosed with prostate cancer

In DNA from prostate tumors, methylation patterns in gene promoter regions can be a biomarker for disease progression. It remains unclear whether methylation patterns in benign prostate tissue--prior to malignant transformation--may provide similar prognostic information. To determine whether early methylation events predict prostate cancer outcomes, we evaluated histologically benign prostate specimens from 353 men who eventually developed prostate cancer and received "definitive" treatment [radical prostatectomy (58%) or radiation therapy (42%)]. Cases were drawn from a large hospital-based cohort of men with benign prostate biopsy specimens collected between 1990 and 2002. Risk of disease progression associated with methylation was estimated using time-to-event analyses. Average follow-up was over 5 years; biochemical recurrence (BCR) occurred in 91 cases (26%). In White men, methylation of the APC gene was associated with increased risk of BCR, even after adjusting for standard clinical risk factors for prostate cancer progression (adjusted hazard ratio (aHR) = 2.26; 95%CI 1.23-4.16). APC methylation was most strongly associated with a significant increased risk of BCR in White men with low prostate specific antigen at cohort entry (HR = 3.66; 95%CI 1.51-8.85). In additional stratified analyses, we found that methylation of the RARB gene significantly increased risk of BCR in African American cases who demonstrated methylation of at least one of the other four genes under study (HR = 3.80; 95%CI 1.07-13.53). These findings may have implications in the early identification of aggressive prostate cancer as well as reducing unnecessary medical procedures and emotional distress for men who present with markers of indolent disease.