Marital Status, Living Arrangement, and Survival among Individuals with Advanced Prostate Cancer in the International Registry for Men with Advanced Prostate Cancer

BACKGROUND

Studies have shown improved survival among individuals with cancer with higher levels of social support. Few studies have investigated social support and overall survival (OS) in individuals with advanced prostate cancer in an international cohort. We investigated the associations of marital status and living arrangements with OS among individuals with advanced prostate cancer in the International Registry for Men with Advanced Prostate Cancer (IRONMAN).

METHODS

IRONMAN is enrolling participants diagnosed with advanced prostate cancer (metastatic hormone-sensitive prostate cancer, mHSPC; castration-resistant prostate cancer, CRPC) from 16 countries. Participants in this analysis were recruited between July 2017 and January 2023. Adjusting for demographics and tumor characteristics, the associations were estimated using Cox regression and stratified by disease state (mHSPC, CRPC), age (<70, ≥70 years), and continent of enrollment (North America, Europe, Other).

RESULTS

We included 2,119 participants with advanced prostate cancer, of whom 427 died during up to 5 years of follow-up (median 6 months). Two-thirds had mHSPC. Most were married/in a civil partnership (79%) and 6% were widowed. Very few married participants were living alone (1%), while most unmarried participants were living alone (70%). Married participants had better OS than unmarried participants [adjusted HR: 1.44; 95% confidence interval (CI): 1.02-2.02]. Widowed participants had the worst survival compared with married individuals (adjusted HR: 1.89; 95% CI: 1.22-2.94).

CONCLUSIONS

Among those with advanced prostate cancer, unmarried and widowed participants had worse OS compared with married participants.

IMPACT

This research highlighted the importance of social support in OS within this vulnerable population.

Pain and Its Association with Survival for Black and White Individuals with Advanced Prostate Cancer in the United States

Bone pain is a well-known quality-of-life detriment for individuals with prostate cancer and is associated with survival. This study expands previous work into racial differences in multiple patient-reported dimensions of pain and the association between baseline and longitudinal pain and mortality. This is a prospective cohort study of individuals with newly diagnosed advanced prostate cancer enrolled in the International Registry for Men with Advanced Prostate Cancer (IRONMAN) from 2017 to 2023 at U.S. sites. Differences in four pain scores at study enrollment by race were investigated. Cox proportional hazards models and joint longitudinal survival models were fit for each of the scale scores to estimate HRs and 95% confidence intervals (CI) for the association with all-cause mortality. The cohort included 879 individuals (20% self-identifying as Black) enrolled at 38 U.S. sites. Black participants had worse pain at baseline compared with White participants, most notably a higher average pain rating (mean 3.1 vs. 2.2 on a 10-point scale). For each pain scale, higher pain was associated with higher mortality after adjusting for measures of disease burden, particularly for severe bone pain compared with no pain (HR, 2.47; 95% CI: 1.44-4.22). The association between pain and all-cause mortality was stronger for participants with castration-resistant prostate cancer compared with those with metastatic hormone-sensitive prostate cancer and was similar among Black and White participants. Overall, Black participants reported worse pain than White participants, and more severe pain was associated with higher mortality independent of clinical covariates for all pain scales.

SIGNIFICANCE

Black participants with advanced prostate cancer reported worse pain than White participants, and more pain was associated with worse survival. More holistic clinical assessments of pain in this population are needed to determine the factors upon which to intervene to improve quality of life and survivorship, particularly for Black individuals.

A harmonized resource of integrated prostate cancer clinical, -omic, and signature features

Genomic and transcriptomic data have been generated across a wide range of prostate cancer (PCa) study cohorts. These data can be used to better characterize the molecular features associated with clinical outcomes and to test hypotheses across multiple, independent patient cohorts. In addition, derived features, such as estimates of cell composition, risk scores, and androgen receptor (AR) scores, can be used to develop novel hypotheses leveraging existing multi-omic datasets. The full potential of such data is yet to be realized as independent datasets exist in different repositories, have been processed using different pipelines, and derived and clinical features are often not provided or  not standardized. Here, we present the curatedPCaData R package, a harmonized data resource representing >2900 primary tumor, >200 normal tissue, and >500 metastatic PCa samples across 19 datasets processed using standardized pipelines with updated gene annotations. We show that meta-analysis across harmonized studies has great potential for robust and clinically meaningful insights. curatedPCaData is an open and accessible community resource with code made available for reproducibility.

Abstract 737: Variation in prognostic value of Gleason score for lethal prostate cancer using time-varying area under the curve

Background: Gleason score is one of the strongest prognostic factors for prostate cancer survival in patients with primary prostate cancer. However, its predictive accuracy is less clear during extended follow-up periods.

Methods: We included men diagnosed with prostate cancer in the Physicians’ Health Study (PHS) and Health Professionals Follow-up Study (HPFS) between 1982 and 2009. We included individuals with available radical prostatectomy tissue specimens and undertook a central standardized histopathologic re-review of H&E slides including Gleason score according to the 2014 International Society of Urological Pathology Consensus. Comparing pathologic Gleason score, we estimated hazard ratios (HR) and 95% confidence intervals (CIs) for lethal prostate cancer-free survival from the time of diagnosis using the Cox proportional hazards regression through 2018. Lethal prostate cancer was defined as development of distant metastases or prostate cancer-specific death. We assessed the time-dependent predictive accuracy of Gleason score over 10, 15, 20, and 25-years post-diagnosis with time-varying area under the curve (tAUC) using the Uno estimator.

Results: Among the 1,404 prostate cancer patients, 113 developed lethal prostate cancer during a follow-up of up to 30 years (median 17.1 years). There were 11% men with Gleason score of 9-10 (grade group 5), 7.1% with 8 (grade group 4), 23% with 4+3 (grade group 3), 36% with 3+4 (grade group 2), and 23% with 6 (grade group 1). Compared to Gleason score 6, the HRs for lethal disease were 5.6 (95% CI: 1.3 to 24) for score 3+4, 13 (95% CI: 3.1 to 55) for 4+3, 17 (95% CI: 3.8 to 75) for 8, and 27 (95% CI: 6.5 to 117) for 9-10, adjusting for pathological tumor stage, age at diagnosis, and prostate-specific antigen (PSA) level at diagnosis. The overall AUC over the entire follow-up was 0.71 (95% CI: 0.63 to 0.79) for Gleason score alone and 0.76 (95% CI: 0.68 to 0.83) with the addition of stage, PSA, and age. Discrimination for lethal prostate cancer based on Gleason score alone varied over follow-up, peaking at a tAUC of 0.81 (95% CI: 0.77 to 0.85) at 10 years, and slowly declined to 0.78 (95% CI: 0.74 to 0.83) at 15 years, 0.78 (95% CI: 0.74 to 0.81) at 20 years, and 0.74 (95% CI: 0.69 to 0.80) at 25 years post-diagnosis. The tAUC had a similar trend with the addition of stage, PSA, and age, with higher point estimates at each time point.

Conclusions: The prognostic value of Gleason score for lethal prostate cancer after prostatectomy, based on genitourinary pathologist re-review, remains high for decades after diagnosis, with only a modest decline over time. Given the long natural history of prostate cancer, an understanding of the factors that contribute to remaining metastasis-free is needed to inform clinical decisions.

Citation Format: Zhike Lin, Konrad H. Stopsack, Michelangelo Fiorentino, Jane B. Vaselkiv, Travis Gerke, Andreas Pettersson, Sinead Flanagan, Kathryn L. Penney, Stephen P. Finn, Massimo Loda, Lorelei A. Mucci. Variation in prognostic value of Gleason score for lethal prostate cancer using time-varying area under the curve [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 737.

Abstract P4-07-20: Effect of prior treatments on post-CDK 4/6 inhibitor overall survival in hormone receptor positive breast cancer

Purpose: There are multiple treatment options for patients with metastatic breast cancer (MBC); however, there is minimal data on the optimal sequencing. Furthermore, limited information is available to understand the influence of prior treatment duration and class on novel therapies in real-world settings, such as cyclin-dependent kinase 4/6 inhibitors (CDK 4/6i) for patients with hormone receptor-positive, human epidermal growth factor receptor 2- negative (HR+ HER2-) MBC. Our study sought to identify the effect of prior treatments on post-CDK 4/6i survival.

Methods: This retrospective study used the nationwide, de-identified electronic health record-derived Flatiron Health database of women with HR+ HER2- MBC who received at least one CDK 4/6i between 2011 and 2020. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated for the association between duration and class of all cancer treatments prior to receipt of CDK 4/6i and overall survival (OS) adjusting for age at diagnosis, race and ethnicity, site of metastasis, and metastatic diagnosis year. Time dependent HRs were used to compare the OS for patients receiving one versus multiple CDK 4/6i.

Results: Of 5,363 patients, most were aged 55-64 (29%), White (69%), and had visceral metastasis (70%). The median survival from receipt of first CDK 4/6 inhibitor was 3.3 years. When compared to patients with no prior treatments, patients with up to one year of prior treatments had a 30% increased hazard of death ((HR, 1.30; 95% CI 1.15-1.46; Table 1). Similarly, patients with one to less than three years of prior treatment had a 68% increased hazard of death (HR 1.68; 95% CI 1.49-1.88) and those with three or more years had a 55% increased hazard of death (HR 1.55; 95% CI 1.36-1.76). Furthermore, patients who received prior endocrine therapy alone experienced a 29% increased hazard of death (HR, 1.29; 95% CI 1.16-1.44), while patients receiving prior chemotherapy experienced a 72% increased hazard of death (HR, 1.72; 95% CI 1.54-1.93) when compared with patients who did not receive a prior treatment. Finally, patients who received a different CDK 4/6i after their first had a 17% decreased hazard of death compared to patients who received subsequent endocrine or chemotherapy after their first CDK 4/6i (HR, 0.83; 95% CI 0.71-0.96).

Conclusion: Prior treatment duration and class are associated with a decreased overall survival after CDK 4/6 inhibitor administration. However, patients receiving more than one CDK 4/6 inhibitor in their sequence saw survival benefits. This highlights the importance for clinicians to consider prior treatment and duration in treatment decision-making and for trialists to stratify by these factors when reporting results of future studies.

Table 1: The association between OS and treatment duration and class before CDK 4/6

Citation Format: Jeffrey Franks, Nicole E. Caston, Ahmed Elkhanany, Travis Gerke, Andres Azuero, Gabrielle B. Rocque. Effect of prior treatments on post-CDK 4/6 inhibitor overall survival in hormone receptor positive breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-20.

curatedPCaData: Integration of clinical, genomic, and signature features in a curated and harmonized prostate cancer data resource

Genomic and transcriptomic data have been generated across a wide range of prostate cancer (PCa) study cohorts. These data can be used to better characterize the molecular features associated with clinical outcomes and to test hypotheses across multiple, independent patient cohorts. In addition, derived features, such as estimates of cell composition, risk scores, and androgen receptor (AR) scores, can be used to develop novel hypotheses leveraging existing multi-omic datasets. The full potential of such data is yet to be realized as independent datasets exist in different repositories, have been processed using different pipelines, and derived and clinical features are often not provided or unstandardized. Here, we present the curatedPCaData R package, a harmonized data resource representing >2900 primary tumor, >200 normal tissue, and >500 metastatic PCa samples across 19 datasets processed using standardized pipelines with updated gene annotations. We show that meta-analysis across harmonized studies has great potential for robust and clinically meaningful insights. curatedPCaData is an open and accessible community resource with code made available for reproducibility.

Effect of prior treatments on post-CDK 4/6 inhibitor survival in hormone receptor-positive breast cancer

PURPOSE

Multiple treatment options exist for patients with metastatic breast cancer (MBC). However, limited information is available on the impact of prior treatment duration and class on survival outcome for novel therapies, such as cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) for patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+ HER2-) MBC.

METHODS

This study used a nationwide, de-identified electronic health record-derived database to identify women with HR+ HER2- MBC who received at least one CDK 4/6i between 2011 and 2020. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated for the association between prior duration and class of cancer treatment (both early-stage and metastatic) and prior CDK 4/6i survival as well as for those with multiple CDK 4/6i.

RESULTS

Of 5363 patients, the median survival from first CDK 4/6 inhibitor administration was 3.3 years. When compared to patients with no prior treatments, patients with < 1 year of prior treatment duration had a 30% increased hazard of death (HR, 1.30; 95% CI 1.15-1.46), those with 1 to < 3 years a 68% increased hazard of death (HR 1.68; 95% CI 1.49-1.88), and those with 3 or more years a 55% increased hazard of death (HR 1.55; 95% CI 1.36, 1.76). Patients who received prior therapy (endocrine or chemotherapy) before their CDK 4/6i had worse outcomes than those who received no prior therapy. Similar results were seen when comparing patients in the metastatic setting alone. Finally, patients who received a different CDK 4/6i after their first saw a lower hazard of death compared to patients who received subsequent endocrine or chemotherapy after their first CDK 4/6i.

CONCLUSION

Prior treatment duration and class are associated with a decreased overall survival after CDK 4/6 inhibitor administration. This highlights the importance for clinicians to consider prior treatment and duration in treatment decision-making and for trialists to stratify by these factors when randomizing patients or reporting results of future studies.

IRONMAN: A Novel International Registry of Men With Advanced Prostate Cancer

PURPOSE

To describe a newly established international registry recruiting diverse patients with advanced prostate cancer across academic and community practices to address unmet needs in this population.

PATIENTS AND METHODS

Initiated in 2017, IRONMAN (International Registry for Men with Advanced Prostate Cancer) is a prospective cohort of patients with advanced prostate cancer. The study will enroll 5,000 patients with metastatic hormone-sensitive prostate cancer (mHSPC) or castration-resistant prostate cancer (CRPC), recruited from Australia, the Bahamas, Barbados, Brazil, Canada, Ireland, Jamaica, Kenya, Nigeria, Norway, South Africa, Spain, Sweden, Switzerland, the United Kingdom, and the United States. The study is collecting datatypes to study variation in care and treatment of advanced prostate cancer across countries and across academic, community-based, and government practices with a focus on clinical outcomes, patient-reported outcomes, epidemiologic data, biologic subtypes, and clinician questionnaires.

RESULTS

Through July 2022, 2,682 eligible patients were enrolled in 11 of 12 active countries. Sixty-six percent of patients have mHSPC, and 34% have CRPC. On the basis of self-report, 11% of patients are Black and 9% are Hispanic. Five Veterans Affairs Medical Centers are enrolling patients. Globally, 23% of patients report being veterans of military service.

CONCLUSION

To our knowledge, this is the first international cohort of people newly diagnosed with advanced prostate cancer designed to describe variations in patient management, experiences, and outcomes. IRONMAN aims to identify optimal treatment sequences to improve survival, understand patient-reported outcomes, and explore novel biomarkers to understand treatment resistance mechanisms. Insights from IRONMAN will inform and guide future clinical management of people with mHSPC and CRPC. This cohort study will provide real-world evidence to facilitate a better understanding of the survivorship of people with advanced prostate cancer.

Abstract 38: Racial disparities in prostate cancer mortality rates explained by differences in dietary and lifestyle factors

Introduction: Black men have 2.1 times higher prostate cancer mortality rates than White men in the United States, yet the reasons for this disparity remain unclear. Several dietary and lifestyle factors may influence the risk of developing lethal prostate cancer. This study evaluated to what extent differences in the prevalence of modifiable risk factors by race could explain racial disparities in prostate cancer mortality.

Methods: Our study utilized data from the Health Professionals Follow-up Study (HPFS, N=51,529 men, 1986-2016) and the National Health and Nutrition Examination Study (NHANES, 2000-2010). First, we used data from NHANES to estimate the prevalence of three factors among Black and White men: smoking, vitamin D, and coffee. Then, using HPFS, we generated relative risk estimates for lethal prostate cancer for each factor. To estimate the relative prostate cancer burden associated with these risk factors, we calculated the population attributable fraction (PAF) for each factor by self-identified race, defined as the reduction in mortality that would be achieved if the population had been entirely unexposed, compared with the current exposure pattern. We then calculated the difference in the PAF between Black and white men to estimate the difference in mortality reduction between the two groups if all men had been entirely unexposed, assuming causality of risk factors and no effect modification by race.

Results: There were notable differences in the prevalence of several risk factors by race. For example, Black men had significantly lower levels of vitamin D[MLA1], were less likely to drink coffee, and had a higher prevalence of smoking compared to white men. We estimated that eliminating these risk factors among Black men could lead to a reduction in prostate cancer mortality that is 4-14% larger compared to eliminating these risk factors among white men.

Conclusions: Modifiable lifestyle and dietary factors are potentially responsible for a proportion of the racial disparity in prostate cancer mortality. Our future work will expand the modifiable factors as well as incorporating more contemporary comparisons of the prevalence of these factors to predict future disparities in prostate cancer.

Citation Format: Emily Rencsok, Michelle Sodipo, Travis Gerke, Konrad Stopsack, Lorelei Mucci. Racial disparities in prostate cancer mortality rates explained by differences in dietary and lifestyle factors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 38.

Novel Transcriptomic Interactions Between Immune Content and Genomic Classifier Predict Lethal Outcomes in High-grade Prostate Cancer

Grade group 4 and 5 (GG-45) prostate cancer (PCa) patients are at the highest risk of lethal outcomes, yet lack genomic risk stratification for prognosis and treatment selection. Here, we assess whether transcriptomic interactions between tumor immune content score (ICS) and the Decipher genomic classifier can identify most lethal subsets of GG-45 PCa. We utilized whole transcriptome data from 8071 tumor tissue (6071 prostatectomy and 2000 treatment-naïve biopsy samples) to derive four immunogenomic subtypes using ICS and Decipher. When compared across all grade groups, GG-45 samples had the highest proportion of most aggressive subtype-ICS^High/Decipher^High. Subsequent analyses within the GG-45 patient samples (n = 1420) revealed that the ICS^High/Decipher^High subtype was associated with increased genomic radiosensitivity. Additionally, in a multivariable model (n = 335), ICS^High/Decipher^High subtype had a significantly higher risk of distant metastasis (hazard ratio [HR] = 5.41; 95% confidence interval [CI], 2.76-10.6; p ≤  0.0001) and PCa-specific mortality (HR = 10.6; 95% CI, 4.18-26.94; p ≤  0.0001) as compared with ICS^Low/Decipher^Low. The novel immunogenomic subtypes establish a very strong synergistic interaction between ICS and Decipher in identifying GG-45 patients who experience the most lethal outcomes. PATIENT SUMMARY: In this analysis, we identified a novel interaction between the total immune content of prostate tumors and genomic classifier to identify the most lethal subset of patients with grade groups 4 and 5. Our results will aid in the subtyping of aggressive prostate cancer patients who may benefit from combined immune-radiotherapy modalities.

Enabling Precision Medicine in Cancer Care Through a Molecular Data Warehouse: The Moffitt Experience

PURPOSE

The use of genomics within cancer research and clinical oncology practice has become commonplace. Efforts such as The Cancer Genome Atlas have characterized the cancer genome and suggested a wealth of targets for implementing precision medicine strategies for patients with cancer. The data produced from research studies and clinical care have many potential secondary uses beyond their originally intended purpose. Effective storage, query, retrieval, and visualization of these data are essential to create an infrastructure to enable new discoveries in cancer research.

METHODS

Moffitt Cancer Center implemented a molecular data warehouse to complement the extensive enterprise clinical data warehouse (Health and Research Informatics). Seven different sequencing experiment types were included in the warehouse, with data from institutional research studies and clinical sequencing.

RESULTS

The implementation of the molecular warehouse involved the close collaboration of many teams with different expertise and a use case-focused approach. Cornerstones of project success included project planning, open communication, institutional buy-in, piloting the implementation, implementing custom solutions to address specific problems, data quality improvement, and data governance, unique aspects of which are featured here. We describe our experience in selecting, configuring, and loading molecular data into the molecular data warehouse. Specifically, we developed solutions for heterogeneous genomic sequencing cohorts (many different platforms) and integration with our existing clinical data warehouse.

CONCLUSION

The implementation was ultimately successful despite challenges encountered, many of which can be generalized to other research cancer centers.

Prostate Cancer Racial Disparities: A Systematic Review by the Prostate Cancer Foundation Panel

CONTEXT

Prostate cancer (PCa) is a complex disease that disproportionately impacts Black men in the USA. The structural factors that drive heterogeneous outcomes for patients of differing backgrounds are probably the same ones that result in population-level disparities. The relative contribution of drivers along the PCa disease continuum is an active area of investigation and debate.

OBJECTIVE

To critically synthesize the available evidence on PCa disparities from a population-level perspective in comparison to data from "equal access and equal care settings" and to provide a consensus summary of the state of PCa disparities.

EVIDENCE ACQUISITION

A plenary panel on PCa disparities presented at the Prostate Cancer Foundation meeting on October 24, 2019 and ensuing discussions are reported here. We used a systematic literature review approach and the Preferred Reporting Items for Systematic Reviews and Meta-analyses to select the most relevant publications. A total of 3333 publications between 2011 and 2021 were retrieved, of which 52 were included in the review; an additional 13 articles on screening guidelines, seminal clinical trials, and statistical methodology were used in the evidence synthesis.

EVIDENCE SYNTHESIS

Race disparities in PCa are a result of a complex interaction between socioeconomic factors impacting access to care and ancestral/genetic factors that may influence tumor biology. Black men in the USA continue to have a nearly 1.8 times higher population-level mortality rate than White men. Failure to account for the race-specific incidence burden would continue to lead to residual disparity even after achieving relatively similar outcomes after primary treatment, resulting in a higher long-term mortality burden. Selection bias remains possible in PCa studies, which often rely on highly specific cohorts of Black men with higher use of health care resources that may not represent the average Black patient in the USA. Novel methods including mediation analysis and genetic ancestry rather than self-identified race can optimize analytical models investigating racial disparities and may lead to a better understanding of PCa genomic diversity and behavior.

CONCLUSIONS

Our findings emphasize the importance of racially diverse studies, including precision -omics, prevention, and targeted therapy initiatives, to elucidate mechanisms underlying racial differences in outcomes and response to therapy. We propose novel approaches for studying and addressing PCa disparities. Contemporary methods, particularly in the domain of mediation analysis, can promote scientific rigor in understanding these disparities.

PATIENT SUMMARY

Inaccurate data interpretation or lack of data altogether for Black men can impact policy and ultimately affect millions of individuals of African origin worldwide. Our review identifies a need to develop and prioritize a strategy for including Black and other men with prostate cancer in intervention studies and randomized clinical trials to halt the widening prostate cancer disparities.

A polymorphism in the promoter of FRAS1 is a candidate SNP associated with metastatic prostate cancer

BACKGROUND

Inflammation and one of its mediators, NF-kappa B (NFκB), have been implicated in prostate cancer carcinogenesis. We assessed whether germline polymorphisms associated with NFκB are associated with the risk of developing lethal disease (metastases or death from prostate cancer).

METHODS

Using a Bayesian approach leveraging NFκB biology with integration of publicly available datasets we used a previously defined genome-wide functional association network specific to NFκB and lethal prostate cancer. A dense-module-searching method identified modules enriched with significant genes from a genome-wide association study (GWAS) study in a discovery data set, Physicians' Health Study and Health Professionals Follow-up Study (PHS/HPFS). The top 48 candidate single nucleotide polymorphisms (SNPs) from the dense-module-searching method were then assessed in an independent prostate cancer cohort and the one SNP reproducibly associated with lethality was tested in a third cohort. Logistic regression models evaluated the association between each SNP and lethal prostate cancer. The candidate SNP was assessed for association with lethal prostate cancer in 6 of 28 studies in the prostate cancer association group to investigate cancer associated alterations in the genome (PRACTICAL) Consortium where there was some medical record review for death ascertainment which also had SNP data from the ONCOARRAY platform. All men self-identified as Caucasian.

RESULTS

The rs1910301 SNP which was reproducibly associated with lethal disease was nominally associated with lethal disease (odds ratio [OR] = 1.40; p = .02) in the discovery cohort and the minor allele was also associated with lethal disease in two independent cohorts (OR = 1.35; p = .04 and OR = 1.35; p = .07). Fixed effects meta-analysis of all three cohorts found an association: OR = 1.37 (95% confidence interval [CI]: 1.15-1.62, p = .0003). This SNP is in the promoter region of FRAS1, a gene involved in epidermal-basement membrane adhesion and is present at a higher frequency in men with African ancestry. No association was found in the subset of studies from the PRACTICAL consortium studies which had a total of 106 deaths out total of 3263 patients and a median follow-up of 4.4 years.

CONCLUSIONS

Through its connection with the NFκB pathway, a candidate SNP with a higher frequency in men of African ancestry without cancer was found to be associated with lethal prostate cancer across three well-annotated independent cohorts of Caucasian men.

KLK3 SNP-SNP interactions for prediction of prostate cancer aggressiveness

Risk classification for prostate cancer (PCa) aggressiveness and underlying mechanisms remain inadequate. Interactions between single nucleotide polymorphisms (SNPs) may provide a solution to fill these gaps. To identify SNP-SNP interactions in the four pathways (the angiogenesis-, mitochondria-, miRNA-, and androgen metabolism-related pathways) associated with PCa aggressiveness, we tested 8587 SNPs for 20,729 cases from the PCa consortium. We identified 3 KLK3 SNPs, and 1083 (P < 3.5 × 10-9) and 3145 (P < 1 × 10-5) SNP-SNP interaction pairs significantly associated with PCa aggressiveness. These SNP pairs associated with PCa aggressiveness were more significant than each of their constituent SNP individual effects. The majority (98.6%) of the 3145 pairs involved KLK3. The 3 most common gene-gene interactions were KLK3-COL4A1:COL4A2, KLK3-CDH13, and KLK3-TGFBR3. Predictions from the SNP interaction-based polygenic risk score based on 24 SNP pairs are promising. The prevalence of PCa aggressiveness was 49.8%, 21.9%, and 7.0% for the PCa cases from our cohort with the top 1%, middle 50%, and bottom 1% risk profiles. Potential biological functions of the identified KLK3 SNP-SNP interactions were supported by gene expression and protein-protein interaction results. Our findings suggest KLK3 SNP interactions may play an important role in PCa aggressiveness.

Tackling Diversity in Prostate Cancer Clinical Trials: A Report From the Diversity Working Group of the IRONMAN Registry

Prostate cancer disproportionately affects racial and ethnic minority populations. Reasons for disparate outcomes among minority patients are multifaceted and complex, involving factors at the patient, provider, and system levels. Although advancements in our understanding of disease biology have led to novel therapeutics for men with advanced prostate cancer, including the introduction of biomarker-driven therapeutics, pivotal translational studies and clinical trials are underrepresented by minority populations. Despite attempts to bridge the disparities gap, there remains an unmet need to expand minority engagement and participation in clinical trials to better define the impact of therapy on efficacy outcomes, quality of life, and role of biomarkers in diverse patient populations. The IRONMAN registry (ClinicalTrials.gov identifier: NCT03151629), a global, prospective, population-based study, was borne from this unmet medical need to address persistent gaps in our knowledge of advanced prostate cancer. Through integrated collection of clinical outcomes, patient-reported outcomes, epidemiologic data, and biospecimens, IRONMAN has the goal of expanding our understanding of how and why prostate cancer outcomes differ by race and ethnicity. To this end, the Diversity Working Group of the IRONMAN registry has developed informed strategies for site selection, recruitment, engagement and retention, and trial design and eligibility criteria to ensure broad inclusion and needs awareness of minority participants. In concert with systematic strategies to tackle the complex levels of disparate care, our ultimate goal is to expand minority engagement in clinical research and bridge the disparities gap in prostate cancer care.

Cancer Informatics for Cancer Centers (CI4CC): Building a Community Focused on Sharing Ideas and Best Practices to Improve Cancer Care and Patient Outcomes

Cancer Informatics for Cancer Centers (CI4CC) is a grassroots, nonprofit 501c3 organization intended to provide a focused national forum for engagement of senior cancer informatics leaders, primarily aimed at academic cancer centers anywhere in the world but with a special emphasis on the 70 National Cancer Institute-funded cancer centers. Although each of the participating cancer centers is structured differently, and leaders' titles vary, we know firsthand there are similarities in both the issues we face and the solutions we achieve. As a consortium, we have initiated a dedicated listserv, an open-initiatives program, and targeted biannual face-to-face meetings. These meetings are a place to review our priorities and initiatives, providing a forum for discussion of the strategic and pragmatic issues we, as informatics leaders, individually face at our respective institutions and cancer centers. Here we provide a brief history of the CI4CC organization and meeting highlights from the latest CI4CC meeting that took place in Napa, California from October 14-16, 2019. The focus of this meeting was "intersections between informatics, data science, and population science." We conclude with a discussion on "hot topics" on the horizon for cancer informatics.

Tumor protein expression of the DNA repair gene BRCA1 and lethal prostate cancer

DNA repair genes are commonly altered in metastatic prostate cancer, but BRCA1 mutations are rare. Preliminary studies suggest that higher tumor expression of the BRCA1 protein may be associated with worse prognosis. We undertook a prospective study among men with prostate cancer in the Health Professionals Follow-up Study and evaluated BRCA1 via immunohistochemical staining on tissue microarrays. BRCA1 was expressed in 60 of 589 tumors. Prevalence of BRCA1 positivity was 43% in the 14 men with metastases at diagnosis compared with 9% in non-metastatic tumors [difference, 33 percentage points; 95% confidence interval (CI), 7-59]. BRCA1-positive tumors had 2.16-fold higher Ki-67 proliferative indices (95% CI, 1.18-3.95), higher tumor aneuploidy as predicted from whole-transcriptome profiling, and higher Gleason scores. Among the 575 patients with non-metastatic disease at diagnosis, we evaluated the association between BRCA1 expression and development of lethal disease (metastasis or cancer-specific death, 69 events) during long-term follow-up (median, 18.3 years). A potential weak association of BRCA1 positivity with lethal disease (hazard ratio, 1.61; 95% CI, 0.82-3.15) was attenuated when adjusting for age, Gleason score and clinical stage (hazard ratio, 1.11; 95% CI, 0.54-2.29). In summary, BRCA1 protein expression is a feature of more proliferative and more aneuploid prostate tumors and is more common in metastatic disease. While not well suited as a prognostic biomarker in primary prostate cancer, BRCA1 protein expression may be most relevant in advanced disease.

TMPRSS2-ERG fusion impacts anterior tumor location in men with prostate cancer

BACKGROUND

In prostate cancer (PCa), lack of androgen receptor (AR) regulated TMPRSS2-ETS-related gene (ERG) gene fusion (ERG^negative ) status has been associated with African American race; however, the implications of ERG status for the location of dominant tumors within the prostate remains understudied.

METHODS

An African American-enriched multiinstitutional cohort of 726 PCa patients consisting of both African American men (AAM; n = 254) and European American men (EAM; n = 472) was used in the analyses. Methods of categorical analysis were used. Messenger RNA (mRNA) expression differences between anterior and posterior tumor lesions were analyzed using Wilcoxon rank-sum tests with multiple comparison corrections.

RESULTS

Anti-ERG immunohistochemistry staining showed that the association between ERG status and anterior tumors is independent of race and is consistently robust for both AAM (ERG^negative 81.4% vs. ERG^positive 18.6%; p = .005) and EAM (ERG^negative 60.4% vs. ERG^positive 39.6%; p < .001). In a multivariable model, anterior tumors were more likely to be IHC-ERG^negative (odds ratio [OR]: 3.20; 95% confidence interval [CI]: 2.14-4.78; p < .001). IHC-ERG^negative were also more likely to have high-grade tumors (OR: 1.73; 95% CI: 1.06-2.82; p = .02). In the exploratory genomic analysis, mRNA expression of location-dependent genes is highly influenced by ERG status and African American race. However, tumor location did not impact the expression of AR or the major canonical AR-target genes (KLK3, AMACR, and MYC).

CONCLUSIONS

ERG^negative tumor status is the strongest predictor of anterior prostate tumors, regardless of race. Furthermore, AR expression and canonical AR signaling do not impact tumor location.

Modeling genetic heterogeneity of drug response and resistance in cancer

Heterogeneity in tumors is recognized as a key contributor to drug resistance and spread of advanced disease, but deep characterization of genetic variation within tumors has only recently been quantifiable with the advancement of next generation sequencing and single cell technologies. These data have been essential in developing molecular models of how tumors develop, evolve, and respond to environmental changes, such as therapeutic intervention. A deeper understanding of tumor evolution has subsequently opened up new research efforts to develop mathematical models that account for evolutionary dynamics with the goal of predicting drug response and resistance in cancer. Here, we describe recent advances and limitations of how models of tumor evolution can impact treatment strategies for cancer patients.

Interrelationship Between Health Insurance Status and Prostate Cancer Grade Can Have Critical Impact on Prostate Cancer Disease Control: A Retrospective Cohort Study

The extent to which prostate cancer (PCa) pathology interacts with health insurance to predict PCa outcomes remains unclear. This study will assess the overall association of health insurance on PCa disease control and analyze its interrelationship PCa pathology. A total of 674 PCa patients, treated with prostatectomy from 1987 to 2015, were included in the study. Freedom from biochemical failure (FFbF) was used as a measure of PCa disease control. Methods of categorical and survival analysis were used to analyze the relationships between health insurance, PCa pathology, and FFbF. A total of 63.3% patients were privately insured, 27.1% were publicly insured, and 9.5% were uninsured. In a multivariable model, privately (hazard ratio [HR] = 0.64, 95% confidence interval [CI]: 0.42-0.97, P = .03) and publicly (HR = 0.65, 95% CI: 0.41-1.04, P = .07) insured patients showed improvement in FFbF compared to uninsured patients. The association of health insurance was significantly stronger for the patients with pathologically low grade PCa (pathologic Gleason Score 3+3 & preoperative prostate-specific antigen ≤10 ng/mL), likelihood ratio P = .009. Privately (HR = 0.22, 95% CI: 0.10-0.46) or publicly (HR = 0.26, 95% CI: 0.11-0.60) insured patients with low grade PCa demonstrated favorable association with FFbF. Patients with private and public insurance were more likely to experience favorable treatment. The association of health insurance on PCa disease control is significantly stronger among patients with pathologically low grade PCa. This study identifies health insurance status as pretreatment surrogate for PCa disease control.

Abstract 1574: Circadian clock gene expression and lethal prostate cancer outcomes

Background: Converging evidence points to a potential role of disruption of the circadian rhythm in prostate cancer progression. There is limited human data in prostate tissue examining the biological consequences of alterations in genes involved in circadian rhythm on outcomes among prostate cancer patients.

Methods: To test the hypothesis that tissue expression of circadian-related genes was associated with prostate cancer outcomes, we leveraged data from the Physicians' Health Study (PHS) and the Health Professionals Follow-Up Study (HPFS) prostate tumor cohorts. Whole transcriptome expression profiling was performed on 404 prostate cancer cases, including 113 lethal cases (metastatic disease or prostate cancer death) and 291 indolent cases (&gt;8 years from diagnosis without evidence of metastasis). Using logistic regression models, we assessed whether mRNA expression levels in tumor (N=404) or paired normal prostate tissue (N=202) of eleven circadian-related genes (AANAT, CLOCK, CRY1, CRY2, CSNK1E, MTNR1B, NPAS2, OPN4, PER1, PER2, PER3) were associated with lethal prostate cancer, stage (T2 vs. T3+), Gleason grade at diagnosis (&lt;8 vs. ≥8), and biomarkers of angiogenesis and apoptosis. We calculated odds ratios and 95% confidence intervals (95% CIs) per standard deviation increase in gene expression.

Results: Pathway analyses showed a statistically significant association between the eleven circadian genes and lethal disease (global test p-value = 5.1e-05). On an individual gene level, men with higher tumor expression of Period Circadian Regulator 1 (PER1) gene had a reduced risk of lethal disease, independent of grade and stage (OR: 0.75, 95% CI: 0.59-0.97). High tumor expression of PER1 (OR: 0.72, 95% CI: 0.57-0.91) and Cryptochrome Circadian Regulator 2 (CRY2) (OR: 0.79, 95% CI: 0.63-1.00) were associated with lower Gleason grade tumors. High tumor expression of PER1 was associated with lower levels of cell proliferation and lower levels of angiogenesis markers; Neuronal PAS Domain Protein 2 (NPAS2) was associated with markers of apoptosis. For none of the genes was expression in normal prostate tissue associated with lethal prostate cancer (global test p-value = 0.06).

Discussion: We found higher expression of several of the circadian related genes were associated with less aggressive prostate cancer features. In line with these findings, PER1 has been suggested to be a tumor suppressor in previous studies. This supports the idea that maintenance of circadian clock function may protect tumor progression.

Citation Format: Sarah C. Markt, Ericka Ebot, Iona Cheng, Lynne Wilkens, Ayesha Shafi, Karen Knudsen, Kathryn Penney, Lorelei Mucci, Travis Gerke. Circadian clock gene expression and lethal prostate cancer outcomes [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 1574.

Glioma risk associated with extent of estimated European genetic ancestry in African Americans and Hispanics

Glioma incidence is highest in non-Hispanic Whites, and to date, glioma genome-wide association studies (GWAS) to date have only included European ancestry (EA) populations. African Americans and Hispanics in the US have varying proportions of EA, African (AA) and Native American ancestries (NAA). It is unknown if identified GWAS loci or increased EA is associated with increased glioma risk. We assessed whether EA was associated with glioma in African Americans and Hispanics. Data were obtained for 832 cases and 675 controls from the Glioma International Case-Control Study and GliomaSE Case-Control Study previously estimated to have <80% EA, or self-identify as non-White. We estimated global and local ancestry using fastStructure and RFMix, respectively, using 1,000 genomes project reference populations. Within groups with ≥40% AA (AFR_≥0.4 ), and ≥15% NAA (AMR_≥0.15 ), genome-wide association between local EA and glioma was evaluated using logistic regression conditioned on global EA for all gliomas. We identified two regions (7q21.11, p = 6.36 × 10^-4 ; 11p11.12, p = 7.0 × 10^-4 ) associated with increased EA, and one associated with decreased EA (20p12.13, p = 0.0026) in AFR_≥0.4 . In addition, we identified a peak at rs1620291 (p = 4.36 × 10^-6 ) in 7q21.3. Among AMR_≥0.15 , we found an association between increased EA in one region (12q24.21, p = 8.38 × 10^-4 ), and decreased EA in two regions (8q24.21, p = 0. 0010; 20q13.33, p = 6.36 × 10^-4 ). No other significant associations were identified. This analysis identified an association between glioma and two regions previously identified in EA populations (8q24.21, 20q13.33) and four novel regions (7q21.11, 11p11.12, 12q24.21 and 20p12.13). The identifications of novel association with EA suggest regions to target for future genetic association studies.

Order in The Court? The Association Between Substance Use, Exposure to Violence, Risky Sexual Behaviors & Observed Court Behaviors Among Women Involved in the Criminal Justice System

Drug courts, therapeutic justice programs for individuals charged with drug offenses, have sub-optimal completion rates. The Courtroom Behavior Checklist (CRBCL), an assessment that quantifies readiness for drug court and drug court behaviors, was developed to predict female offenders who may be at-risk for non-compliance and termination. Data derived from 264 mainly urban women recruited from a Municipal Drug Court System in St. Louis, MO, were used to evaluate the association between substance use, victimization, HIV/AIDS risk behaviors, and observed drug court behaviors. Results showed that women who reported recent substance use or were categorized as at risk for HIV/AIDS were significantly more likely to have scores indicative of unfavorable drug court behaviors, while women who experienced victimization had scores indicative of favorable drug court behaviors. Other factors significantly associated with unfavorable drug court behaviors included greater lifetime arrests, lower education, and being less religious or spiritual. Our findings suggest that the CRBCL may have added utility in identifying women in drug court with recent substance use and risky sexual behaviors. However, further studies on other samples of offenders are needed to support these findings.

Intratumoral Sterol-27-Hydroxylase (CYP27A1) Expression in Relation to Cholesterol Synthesis and Vitamin D Signaling and Its Association with Lethal Prostate Cancer

BACKGROUND

Higher intratumoral cholesterol synthesis is associated with a worse prognosis in prostate cancer. The vitamin D-regulated enzyme sterol-27-hydroxylase (CYP27A1) converts cholesterol to 27-hydroxycholesterol, potentially lowering intracellular cholesterol levels. We hypothesized that low CYP27A1 expression is associated with high cholesterol synthesis, low vitamin D signaling, and higher risk of lethal prostate cancer.

METHODS

In 404 patients from the prospective prostate cancer cohorts within the Health Professionals Follow-up Study (HPFS) and the Physicians' Health Study (PHS), we assessed intratumoral CYP27A1 expression and proxies of cholesterol synthesis using transcriptome profiling, prediagnostic plasma 25-hydroxyvitamin D [25(OH)D; n = 132], and intratumoral vitamin D receptor protein expression (VDR; n = 300). Patients were followed for metastases and prostate cancer mortality (lethal cancer; median follow-up, 15.3 years).

RESULTS

CYP27A1 expression was lower in tumors with higher Gleason grade and higher expression of cholesterol synthesis enzymes, including the second rate-limiting enzyme, SQLE. We did not detect consistent associations between CYP27A1 and 25(OH)D, VDR, or CYP24A1 mRNA expression. Lower CYP27A1 was associated with higher risk of lethal cancer in both cohorts, independent of SQLE [adjusted OR for lowest vs. highest quartile of CYP27A1, 2.64; 95% confidence interval (CI), 1.24-5.62]. This association was attenuated when additionally adjusting for Gleason grade (OR, 1.76; 95% CI, 0.75-4.17).

CONCLUSIONS

Low CYP27A1 expression was associated with higher cholesterol synthesis and a higher risk of lethal disease.

IMPACT

These observations further support the hypothesis that intratumoral cholesterol accumulation through higher synthesis and decreased catabolism is a feature of lethal prostate cancer.

Low Expression of the Androgen-Induced Tumor Suppressor Gene PLZF and Lethal Prostate Cancer

BACKGROUND

4%-9% of prostate cancers harbor homozygous deletions of the androgen-induced tumor suppressor gene, promyelocytic leukemia zinc finger (PLZF, ZBTB16). PLZF loss induces an in vitro phenotype of castration resistance and enzalutamide resistance. The association of low expression of PLZF and clinical outcomes is unclear.

METHODS

We assessed PLZF mRNA expression in patients diagnosed with primary prostate cancer during prospective follow-up of the Health Professionals Follow-up Study (HPFS; n = 254) and the Physicians' Health Study (PHS; n = 150), as well as in The Cancer Genome Atlas (n = 333). We measured PTEN status (using copy numbers and IHC) and transcriptional activation of the MAPK pathway. Patients from HPFS and PHS were followed for metastases and prostate cancer-specific mortality (median, 15.3 years; 113 lethal events).

RESULTS

PLZF mRNA expression was lower in tumors with PLZF deletions. There was a strong, positive association between intratumoral androgen receptor (AR) signaling and PLZF expression. PLZF expression was also lower in tumors with PTEN loss. Low PLZF expression was associated with higher MAPK signaling. Patients in the lowest quartile of PLZF expression compared with those in the highest quartile were more likely to develop lethal prostate cancer, independent of clinicopathologic features, Gleason score, and AR signaling (odds ratio, 3.17; 95% confidence interval, 1.32-7.60).

CONCLUSIONS

Low expression of the tumor suppressor gene PLZF is associated with a worse prognosis in primary prostate cancer.

IMPACT

Suppression of PLZF as a consequence of androgen deprivation may be undesirable. PLZF should be tested as a predictive marker for resistance to androgen deprivation therapy.

A Longitudinal Analysis of the Substance Abuse, Violence, and HIV/AIDS (SAVA) Syndemic among Women in the Criminal Justice System

Using data from a randomized controlled trial of 319 women mainly recruited from a Municipal Drug Court System in St. Louis, MO, this study evaluates substance use, victimization, and HIV/AIDS risk behaviors over time. The results indicated that, for all participants, the likelihood of victimization, using drugs, and meeting the criteria for HIV/AIDS risk decreased by 46% by the eight-month follow-up; however, results did not differ significantly by intervention group. Women who were sexually abused as a child, had 4+ arrests, or believed they had sexual and drug-using behaviors that need changing at baseline were more likely to experience these issues over time.

Expression of IGF/insulin receptor in prostate cancer tissue and progression to lethal disease

Circulating insulin-like growth factor-1 (IGF-1) is consistently associated with prostate cancer risk. IGF-1 binds to IGF-1 receptor (IGF1R) and insulin receptor (IR), activating cancer hallmark pathways. Experimental evidence suggests that TMPRSS2:ERG may interact with IGF/insulin signaling to influence progression. We investigated IGF1R and IR expression and its association with lethal prostate cancer among 769 men. Protein expression of IGF1R, IR and ERG (i.e. a surrogate of ERG fusion genes) were assayed by immunohistochemistry. Cox models estimated hazard ratios (HR) and 95% confidence intervals (CI) adjusted for clinical characteristics. Among patients, 29% had strong tumor IGF1R expression and 10% had strong IR expression. During a mean follow-up of 13.2 years through 2012, 80 men (11%) developed lethal disease. Tumors with strong IGF1R or IR expression showed increased cell proliferation, decreased apoptosis and a higher prevalence of ERG. In multivariable models, strong IGF1R was associated with a borderline increased risk of lethal prostate cancer (HR 1.7; 95% CI 0.9-3.1). The association appeared greater in ERG-positive tumors (HR 2.8; 95% CI 0.9-8.4) than in ERG-negative tumors (HR 1.3; 95% CI 0.6-3.0, p-heterogeneity 0.08). There was no association between IR and lethal prostate cancer (HR 0.8; 95% CI 0.4-1.9). These results suggest that tumor IGF1R expression may play a role in prostate cancer progression to a lethal phenotype and that ERG-positive tumors may be more sensitive to IGF signaling. These data may improve our understanding of IGF signaling in prostate cancer and suggest therapeutic options for disease subtypes.

Low Tristetraprolin Expression Is Associated with Lethal Prostate Cancer

BACKGROUND

Inflammation is linked to prostate cancer progression and is mediated by NF-κB. Tristetraprolin is a key node of NF-κB activation and we investigated its biological and prognostic role in lethal prostate cancer.

METHODS

In vitro assays assessed the function of tristetraprolin and the association between low mRNA tristetraprolin levels and lethal prostate cancer (metastatic disease or death) was assessed across independent prostatectomy cohorts: (i) nested case-control studies from Health Professionals Follow-up Study and Physicians' Health Study, and (ii) prostatectomy samples from Cleveland Clinic, Mayo Clinic, Johns Hopkins and Memorial Sloan Kettering Cancer Center. Tristetraprolin expression levels in prostatectomy samples from patients with localized disease and biopsies of metastatic castration-resistant prostate cancer (mCRPC) were assessed in a Cornell University cohort.

RESULTS

In vitro tristetraprolin expression was inversely associated with NF-κB-controlled genes, proliferation, and enzalutamide sensitivity. Men with localized prostate cancer and lower quartile of tumor tristetraprolin expression had a significant, nearly two-fold higher risk of lethal prostate cancer after adjusting for known clinical and histologic prognostic features (age, RP Gleason score, T-stage). Tristetraprolin expression was also significantly lower in mCRPC compared with localized prostate cancer.

CONCLUSIONS

Lower levels of tristetraprolin in human prostate cancer prostatectomy tissue are associated with more aggressive prostate cancer and may serve as an actionable prognostic and predictive biomarker.

IMPACT

There is a clear need for improved biomarkers to identify patients with localized prostate cancer in need of treatment intensification, such as adjuvant testosterone suppression, or treatment de-intensification, such as active surveillance. Tristetraprolin levels may serve as informative biomarkers in localized prostate cancer.

Optimizing Time to Treatment to Achieve Durable Biochemical Disease Control after Surgery in Prostate Cancer: A Multi-Institutional Cohort Study

BACKGROUND

The impact of treatment delays on prostate cancer-specific outcomes remains ill-defined. This study investigates the effect of time to treatment on biochemical disease control after prostatectomy.

METHODS

This retrospective study includes 1,807 patients who received a prostatectomy as a primary treatment at two large tertiary referral centers from 1987 to 2015. Multivariate cox model with restricted cubic spline was used to identify optimal time to receive treatment and estimate the risk of biochemical recurrence.

RESULTS

Median follow-up time of the study was 46 (interquartile range, 18-86) months. Time to treatment was subcategorized based on multivariate cubic spline cox model. In multivariate spline model, adjusted for all the pertinent pretreatment variables, inflection point in the risk of biochemical recurrence was observed around 3 months, which further increased after 6 months. Based on spline model, time to treatment was then divided into 0 to 3 months (61.5%), >3 to 6 months (31.1%), and 6 months (7.4%). In the adjusted cox model, initial delays up to 6 months did not adversely affect the outcome; however, time to treatment >6 months had significantly higher risk of biochemical recurrence (HR, 1.84; 95% confidence interval, 1.30-2.60; P < 0.01).

CONCLUSIONS

The initial delays up to 6 months in prostate cancer primary treatment may be sustainable without adversely affecting the outcome. However, significant delays beyond 6 months can unfavorably affect biochemical disease control.

IMPACT

Time to treatment can aid clinicians in the decision-making of prostate cancer treatment recommendation and educate patients against unintentional treatment delays.

Distinct transcriptional repertoire of the androgen receptor in ETS fusion-negative prostate cancer

Background

Prostate cancer (PCa) tumors harboring translocations of ETS family genes with the androgen responsive TMPRSS2 gene (ETS+ tumors) provide a robust biomarker for detecting PCa in approximately 70% of patients. ETS+ PCa express high levels of the androgen receptor (AR), yet PCa tumors lacking ETS fusions (ETS−) also express AR and demonstrate androgen-regulated growth. In this study, we evaluate the differences in the AR-regulated transcriptomes between ETS+ and ETS− PCa tumors.

Methods

10,608 patient tumors from three independent PCa datasets classified as ETS+ (samples overexpressing ERG or other ETS family members) or ETS− (all other PCa) were analyzed for differential gene expression using false-discovery-rate adjusted methods and gene-set enrichment analysis (GSEA).

Results

Based on the expression of AR-dependent genes and an unsupervised Principal Component Analysis (PCA) model, AR-regulated gene expression alone was able to separate PCa samples into groups based on ETS status in all PCa databases. ETS status distinguished several differentially expressed genes in both TCGA (6.9%) and GRID (6.6%) databases, with 413 genes overlapping in both databases. Importantly, GSEA showed enrichment of distinct androgen-responsive genes in both ETS− and ETS+ tumors, and AR ChIP-seq data identified 131 direct AR-target genes that are regulated in an ETS-specific fashion. Notably, dysregulation of ETS-dependent AR-target genes within the metabolic and non-canonical WNT pathways was associated with clinical outcomes.

Conclusions

ETS status influences the transcriptional repertoire of the AR, and ETS− PCa tumors appear to rely on distinctly different AR-dependent transcriptional programs to drive and sustain tumorigenesis.

Baseline Prostate-specific Antigen Level in Midlife and Aggressive Prostate Cancer in Black Men

BACKGROUND

Prostate-specific antigen (PSA) measurement in midlife predicts long-term prostate cancer (PCa) mortality among white men.

OBJECTIVE

To determine whether baseline PSA level during midlife predicts risk of aggressive PCa in black men.

DESIGN, SETTING, AND PARTICIPANTS

Nested case-control study among black men in the Southern Community Cohort Study recruited between 2002 and 2009. A prospective cohort in the southeastern USA with recruitment from community health centers. A total of 197 incident PCa patients aged 40-64 yr at study entry and 569 controls matched on age, date of blood draw, and site of enrollment. Total PSA was measured in blood collected and stored at enrollment.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Total and aggressive PCa (91 aggressive: Gleason ≥7, American Joint Committee on Cancer stage III/IV, or PCa-specific death). Exact conditional logistic regression estimated odds ratios (ORs) with 95% confidence intervals (CIs) for PCa by category of baseline PSA.

RESULTS AND LIMITATIONS

Median PSA among controls was 0.72, 0.80, 0.94, and 1.03ng/ml for age groups 40-49, 50-54, 55-59, and 60-64 yr, respectively; 90th percentile levels were 1.68, 1.85, 2.73, and 3.33ng/ml. Furthermore, 95% of total and 97% of aggressive cases had baseline PSA above the age-specific median. Median follow-up was 9 yr. The OR for total PCa comparing PSA >90th percentile versus ≤median was 83.6 (95% CI, 21.2-539) for 40-54 yr and 71.7 (95% CI, 23.3-288) for 55-64 yr. For aggressive cancer, ORs were 174 (95% CI, 32.3-infinity) for 40-54 yr and 51.8 (95% CI, 11.0-519) for 55-64 yr. A composite endpoint of aggressive PCa based on stage, grade, and mortality was used and is a limitation.

CONCLUSIONS

PSA levels in midlife strongly predicted total and aggressive PCa among black men. PSA levels among controls were similar to those among white controls in prior studies.

PATIENT SUMMARY

Prostate-specific antigen (PSA) level during midlife strongly predicted future development of aggressive prostate cancer among black men. Targeted screening based on a midlife PSA might identify men at high risk while minimizing screening in those men at low risk.

One Step at a Time: A Latent Transitional Analysis on Changes in Substance Use, Exposure to Violence, and HIV/AIDS Risk Behaviors among Female Offenders

The aim of this analysis is to identify latent subgroups of women based on substance use, exposure to violence, and risky sexual behaviors and quantify discrete stages of behavior change over time. Data comes from 317 women recruited from a Municipal Drug Court System in the Midwest. All participants were interviewed regarding their substance use and sexual behaviors, as well as their exposure to violence at baseline, a 4th-month follow-up, and an 8th-month follow-up. A latent transitional analysis (LTA), a longitudinal extension of a latent class analysis (LCA), was used to quantify discrete stages of behavior change. The results of our analyses revealed 4 distinct behavioral profiles in our sample: 1) women with high probabilities of risky sexual behaviors, exposure to violence, and crack/cocaine use, 2) women with a high probability of exposure to violence, and moderate sexual risk taking, 3) women characterized solely by a high probability of crack/cocaine use, 4) women with low probabilities of all factors. The proportion of women in latent statuses characterized by a high probability of crack/cocaine use did not substantially decrease over time. Women who experienced child sexual abuse, had a greater number of lifetime arrests, were older, and believed they had risky drug using behavior that needed changing at baseline were significantly more likely to be in higher-risk latent statuses. Targeted interventions tailored to crack/cocaine users, as well as a wide-spread need for trauma-informed interventions among females involved in the criminal justice system, are needed.

Abstract A045: All happy families are alike: Transcriptomic homogeneity in indolent prostate tumors is a useful prognostic biomarker

Purpose: To derive a gene expression score of transcriptomic homogeneity in localized prostate tumor specimens, and assess its prognostic utility for metastatic or lethal disease.

Background: At the time of prostate cancer diagnosis, improved biomarkers are needed to distinguish tumors with metastatic potential versus those likely to follow an indolent course. Previous evidence suggests that gene expression aberrations are homogeneous in nonaggressive tumors, while transcriptomic profiles are disregulated in widely varying patterns across metastasis-prone tumors. Here, we investigate whether a measure of transcriptomic homogeneity has prognostic utility.

Study Population: Gene expression profiles of noncancerous prostate tissue from the Genotype-Tissue Expression (GTEx) project (n = 106) were used to develop the homogeneity measure. Prognostic utility of the score was assessed in a study nested in the Health Professionals Follow-up Study (HPFS) and Physicians’ Health Study (PHS), in which whole-transcriptome gene expression was quantified from archival surgical tumor tissue. Cases (n = 113) were men who died of prostate cancer or developed metastatic disease, and controls (n = 291) had at least 8 years of metastasis-free survival. Men were diagnosed with prostate cancer between 1982 and 2005, and median follow-up time was 14.0 years. TCGA data (n = 333) were further used to investigate associations of the expression score with Gleason.

Methods: RNA-seq profiles from GTEx were filtered to retain genes persistently expressed across noncancerous prostate tissue specimens. Remaining genes were placed into decile bins on the basis of median expression across samples. The 25 lowest variance genes within each bin were selected to generate a 250-gene panel. Transcriptome homogeneity scores for patients in HPFS and PHS were calculated by summing the standard deviations over the decile bins, where standard deviations were calculated using patient-specific data across 25 genes in each bin. Associations between the score and lethal disease were assessed through logistic regression and AUC analyses. Associations between the homogeneity score and Gleason score in TCGA samples were evaluated via Pearson correlations.

Results: High transcriptomic heterogeneity was strongly associated with lethal or metastatic outcomes. A crude odds ratio of 3.36 (95% CI 2.12-5.41; p&lt;0.001) was estimated for patients with above median heterogeneity scores compared to those with homogenous expression (those with less than or equal to median heterogeneity). This association persisted with adjustment for Gleason (&lt;7, 3+4, 4+3, 8, 9-10) with an odds ratio of 2.04 (95% CI 1.19-3.51; p=0.01). Addition of heterogeneity scores to Gleason improved the AUC of the Gleason-only model from 0.82 (95% CI 0.77-0.86) to 0.84 (95% CI 0.80-0.88; p=0.01 for improvement). Higher heterogeneity also tracked with higher Gleason score in TCGA with a correlation of 0.33 (95% CI 0.23-0.42; p&lt;0.001).

Conclusions: Transcriptomic homogeneity, as measured by variation across gene sets that are typically stable in normal prostate tissue, is able to distinguish indolent from lethal prostate cancers. Further investigation and discovery of gene sets using this novel approach is likely to deliver new biologic insights and clinically actionable biomarker sets.

Citation Format: Travis Gerke, Svitlana Tyekucheva, Jordan H. Creed, Kathryn L. Penney, Jennifer A. Sinnott, Ericka Ebot, Anders E. Berglund, Massimo Loda, Meir J. Stampfer, Peter Kraft, Giovanni Parmigiani, Lorelei A. Mucci. All happy families are alike: Transcriptomic homogeneity in indolent prostate tumors is a useful prognostic biomarker [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr A045.

Tristetraprolin Is a Prognostic Biomarker for Poor Outcomes among Patients with Low-Grade Prostate Cancer

Background: We studied the utility of the tumor suppressor Tristetraprolin (TTP, ZFP36) as a clinically relevant biomarker of aggressive disease in prostate cancer patients after radical prostatectomy (RP).Methods: TTP RNA expression was measured in an RP cohort of patients treated at Moffitt Cancer Center (MCC) and obtained from six publically available RP datasets with biochemical recurrence (BCR; total n = 1,394) and/or metastatic outcome data (total n = 1,222). TTP protein expression was measured by immunohistochemistry in a tissue microarray of 153 MCC RP samples. The time to BCR or metastasis based on TTP RNA or protein levels was calculated using the Kaplan-Meier analysis. Univariable and multivariable Cox proportional hazard models were performed on multiple cohorts to evaluate if TTP is a clinically relevant biomarker and to assess if TTP improves upon the Cancer of the Prostate Risk Assessment postsurgical (CAPRA-S) score for predicting clinical outcomes.Results: In all of the RP patient cohorts, prostate cancer with low TTP RNA or protein levels had decreased time to BCR or metastasis versus TTP-high tumors. Further, the decreased time to BCR in TTP-low prostate cancer was more pronounced in low-grade tumors. Finally, pooled survival analysis suggests that TTP RNA expression provides independent information beyond CAPRA-S to predict BCR.Conclusions: TTP is a promising prostate cancer biomarker for predicting which RP patients will have poor outcomes, especially for low-grade prostate cancer patients.Impact: This study suggests that TTP RNA expression can be used to enhance the accuracy of CAPRA-S to predict outcomes in patients treated with RP. Cancer Epidemiol Biomarkers Prev; 27(11); 1376-83. ©2018 AACR.

Family History of Breast or Prostate Cancer and Prostate Cancer Risk

PURPOSE

Breast and prostate cancer co-occur in families, and women with a family history of prostate cancer are at increased breast cancer risk. Prostate cancer is among the most heritable cancers, but few studies have investigated its association with familial breast cancer. The objective of this study is to investigate the extent to which familial breast or prostate cancer in first-degree relatives increases prostate cancer risk.

EXPERIMENTAL DESIGN

A prospective study of 37,002 U.S. men in the Health Professionals Follow-up Study. During the 16-year follow-up to 2012, 4,208 total and 344 lethal cases were diagnosed. Using cause-specific hazards regression, we estimated the multivariable HRs and 95% confidence intervals (CI) for associations between familial breast or prostate cancer and total and lethal prostate cancer.

RESULTS

Those with familial breast cancer had a 21% greater risk of prostate cancer overall (95% CI, 1.10-1.34), and a 34% greater risk of lethal disease (HR 1.34; 95% CI, 0.96-1.89). Family history of prostate cancer alone was associated with a 68% increased risk of total disease (95% CI, 1.53-1.83) and a 72% increased risk of lethal disease (95% CI, 1.25-2.38). Men with a family history of both cancers were also at elevated risk.

CONCLUSIONS

Our study found that men with a family history of breast or prostate cancer had elevated prostate cancer risks, including risk of lethal disease. These findings have translational relevance for cancer risk prediction in men.

Abstract 233: Evaluating glioma risk associated with extent of European admixture in African-Americans and Latinos

Glioma incidence is highest in non-Hispanic Whites, where it occurs ~2x as frequently compared with other race/ethnicity groups. Glioma GWAS to date have included European ancestry populations only, and it is unknown whether variants identified by these analyses are associated with glioma in non- European ancestry populations. African Americans and Hispanics are admixed populations with varying proportions of European ancestry. While global ancestry may be similar within admixed groups, the proportion of European ancestry at each allele can vary across the genome. As glioma is more common in European ancestry populations, the presence of increased local European ancestry in these admixed populations could be used to identify glioma risk loci. Here we assessed whether excess European ancestry at established risk loci (Melin et al, Nature Genetics, 2017) was associated with glioma risk in non-European ancestry populations. Global ancestry was estimated using fastStructure, and local ancestry was estimated using RFMix. Both methods used 1,000 genomes project reference populations (African: YRI; European: CEU; East Asian: CHB/JPT; and Native American: CLM/PEL/MXL). We evaluated differences in local European ancestry between cases and controls using logistic regression conditioned on global European ancestry within 500kb of 25 previously identified risk variants among individuals with ≥50% African ancestry, and ≥30% Native American ancestry for all gliomas, and for grade IV glioblastoma (GBM) and grade II-III non-GBM. There were 347 individuals (184 cases and 163 controls) with ≥50% global African ancestry, and 277 individuals (153 cases and 124 controls) with ≥30% global American ancestry. There was no significant difference in proportion of global European ancestry between cases and controls with ≥50% global African ancestry (cases: 18.2%, controls: 17.7%, p=0.6834), and no significant difference in proportion of global European ancestry between cases and controls with ≥30% global American ancestry (cases: 51.1%, controls: 49.0%, p=0.2123). Among individuals with &gt;50% African ancestry, we observed a nominally significant association between all glioma and increased local European ancestry at 7p11.2 (EGFR, pmin=0.0070) and between GBM and increased local European ancestry at 22q13.1 (CSNK1E, pmin=0.0098), both near SNPs previously associated with glioblastoma in majority European-ancestry populations. The dataset used for this analysis represents the largest collection of genotyped non-European glioma cases. These results suggest that glioma risk in African Americans may be associated with an increased local European ancestry variants at glioma risk loci previously identified in majority European ancestry populations (7p11.2 and 22q13.1).

Citation Format: Quinn T. Ostrom, Kathleen M. Egan, L. Burt Nabors, Travis Gerke, Reid C. Thompson, Jeffrey J. Olson, Renato LaRocca, Sajeel Chowdhary, Jeanette E. Eckel-Passow, Georgina Armstrong, John K. Wiencke, Christopher I. Amos, Jonine L. Bernstein, Elizabeth B. Claus, Dora Il'yasova, Christoffer Johansen, Daniel H. Lachance, Rose Lai, Ryan T. Merrell, Sara H. Olson, Siegal Sadetzki, Joellen Schildkraut, Sanjay Shete, Richard S. Houlston, Robert B. Jenkins, Beatrice Melin, Melissa L. Bondy, Jill S. Barnholtz-Sloan. Evaluating glioma risk associated with extent of European admixture in African-Americans and Latinos [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 233.

African-American men and prostate cancer-specific mortality: a competing risk analysis of a large institutional cohort, 1989-2015

Significant racial disparities in prostate cancer (PCa) outcomes have been reported, with African-American men (AAM) more likely to endure adverse oncologic outcomes. Despite efforts to dissipate racial disparities in PCa, a survival gap persists and it remains unclear to what extent this disparity can be explained by known clinicodemographic factors. In this study, we leveraged our large institutional database, spanning over 25 years, to investigate whether AAM continued to experience poor PCa outcomes and factors that may contribute to racial disparities in PCa. A total of 7307 patients diagnosed with PCa from 1989 through 2015 were included. Associations of race and clinicodemographic characteristics were analyzed using chi-square for categorical and Mann-Whitney U-test for continuous variables. Racial differences in prostate cancer outcomes were analyzed using competing risk analysis methods of Fine and Gray. Median follow-up time was 106 months. There were 2304 deaths recorded, of which 432 resulted from PCa. AAM were more likely to be diagnosed at an earlier age (median 60 vs. 65 years, P = <0.001) and were more likely to have ≥1 comorbidities (13.6% vs. 7.5%, P < 0.001). In a multivariate competing risk model, adjusted for baseline covariates, AAM experienced significantly higher risk of PCSM compared to NHW men (HR, 1.62, 95% CI, 1.02-2.57, P = 0.03) NHW. Among men diagnosed at an older age (>60 years), racial differences in PCSM were more pronounced, with AAM experiencing higher rates of PCSM (HR, 2.05, 95% CI, 1.26-3.34, P = 0.003). After adjustment of clinicodemographic and potential risk factors, AAM continue to experience an increased risk of mortality from PCa, especially older AAM. Furthermore, AAM are more likely to be diagnosed at an early age and more likely to have higher comorbidity indices.

Substance Use, Victimization, HIV/AIDS Risk, And Recidivism Among Females in A Therapeutic Justice Program

This analysis examines the association between crack/cocaine use only and the SAVA syndemic ((any substance use, AND being exposed to violence, AND having HIV/AIDS risk behaviors) at baseline and any felony, misdemeanor, or municipal violations by an 8-month follow-up. Data comes from 317 women recruited from a Municipal Drug Court System in the Midwest. Among the sample, 45% of the women had at least one felony, misdemeanor, or a municipal violation at the 8-month follow-up (felony: 20%; misdemeanor or municipal violation 25%). Multinomial regression revealed that crack/cocaine use and SAVA at baseline were associated specifically with misdemeanors OR 2.21 (95% CI: 1.21, 4.04) and OR 3.60 (95% CI: 1.23, 10.56) respectively, no increases in odds of felonies were evident. Women with a higher number of lifetime arrests were also significantly more likely to have a greater number of offenses postbaseline, while black women were considerably less likely to be charged with misdemeanors. Recent crack/cocaine use with or without the mutually reinforcing issues of victimization, and HIV/AIDS risk behaviors significantly increased the odds of a misdemeanors/municipal violation. However, significant increases in odds of more severe offenses (felonies) were not evident. Interventions aimed to reduce offenses should offer additional support for crack/cocaine users.

MYC Overexpression at the Protein and mRNA Level and Cancer Outcomes among Men Treated with Radical Prostatectomy for Prostate Cancer

Background: The proto-oncogene MYC is implicated in prostate cancer progression. Whether MYC tumor expression at the protein or mRNA level is associated with poorer prognosis has not been well studied.Methods: We conducted a cohort study including 634 men from the Physicians' Health Study and Health Professionals Follow-up Study treated with radical prostatectomy for prostate cancer in 1983-2004 and followed up for a median of 13.7 years. MYC protein expression was evaluated using IHC, and we used Cox regression to calculate HRs and 95% confidence intervals (CIs) of its association with lethal prostate cancer (distant metastases/prostate cancer-related death). We assessed the association between MYC mRNA expression and lethal prostate cancer in a case-control study, including 113 lethal cases and 291 indolent controls.Results: MYC nuclear protein expression was present in 97% of tumors. MYC protein expression was positively correlated with tumor proliferation rate (r = 0.37; P < 0.001) and negatively correlated with apoptotic count (r = -0.17; P < 0.001). There were no significant associations between MYC protein expression and stage, grade, or PSA level at diagnosis. The multivariable HR for lethal prostate cancer among men in the top versus bottom quartile of MYC protein expression was 1.09 (95% CI, 0.50-2.35). There was no significant association between MYC mRNA expression and lethal prostate cancer.Conclusions: Neither MYC protein overexpression nor MYC mRNA overexpression are strong prognostic markers in men treated with radical prostatectomy for prostate cancer.Impact: This is the largest study to examine the prognostic role of MYC protein and mRNA expression in prostate cancer. Cancer Epidemiol Biomarkers Prev; 27(2); 201-7. ©2017 AACR.

Interactions of Family History of Breast Cancer with Radiotherapy in Relation to the Risk of Breast Cancer Recurrence

Purpose

We examined associations between a family history of breast cancer and the risk of breast cancer recurrence in women who received or did not receive radiotherapy.

Methods

Our study included 2,440 women enrolled in the Breast Cancer Registry of Greater Cincinnati. Information on breast cancer risk factors, including detailed family history of breast cancer, characteristics of the primary tumor, treatment received, and recurrence status was collected at baseline and via updates. Associations between a family history of breast cancer and the risk of breast cancer recurrence were examined separately in women treated with and without radiotherapy using survival analysis.

Results

Over an average follow-up time of 8.78 years, we found no associations between a family history of breast cancer and the risk of breast cancer recurrence among women with a history of radiotherapy (hazard ratio [HR], 0.96; 95% confidence interval [CI], 0.75–1.23). Among women who did not receive radiotherapy, the total number of relatives with breast cancer was positively associated with the risk of breast cancer recurrence (HR, 1.21; 95% CI, 1.00–1.47). We found no interactions of radiotherapy with family history (p-interaction >0.05).

Conclusion

Radiotherapy for a primary breast cancer in women with a family history of breast cancer does not increase risk of breast cancer recurrence. If these findings are replicated in future studies, the results may translate into an important health message for breast cancer survivors with a family history of breast cancer.

Height, Obesity, and the Risk of TMPRSS2:ERG-Defined Prostate Cancer

Background: The largest molecular subtype of primary prostate cancer is defined by the TMPRSS2:ERG gene fusion. Few studies, however, have investigated etiologic differences by TMPRSS2:ERG status. Because the fusion is hormone-regulated and a man's hormonal milieu varies by height and obesity status, we hypothesized that both may be differentially associated with risk of TMPRSS2:ERG-defined disease.Methods: Our study included 49,372 men from the prospective Health Professionals Follow-up Study. Participants reported height and weight at baseline in 1986 and updated weight biennially thereafter through 2009. Tumor ERG protein expression (a TMPRSS2:ERG marker) was immunohistochemically assessed. We used multivariable competing risks models to calculate HRs and 95% confidence intervals (CIs) for the risk of ERG-positive and ERG-negative prostate cancer.Results: During 23 years of follow-up, we identified 5,847 incident prostate cancers, among which 913 were ERG-assayed. Taller height was associated with an increased risk of ERG-positive disease only [per 5 inches HR 1.24; 95% confidence interval (CI), 1.03-1.50; P_{heterogeneity} = 0.07]. Higher body mass index (BMI) at baseline (per 5 kg/m² HR 0.75; 95% CI, 0.61-0.91; P_{heterogeneity} = 0.02) and updated BMI over time (per 5 kg/m² HR 0.86; 95% CI, 0.74-1.00; P_{heterogeneity} = 0.07) were associated with a reduced risk of ERG-positive disease only.Conclusions: Our results indicate that anthropometrics may be uniquely associated with TMPRSS2:ERG-positive prostate cancer; taller height may be associated with greater risk, whereas obesity may be associated with lower risk.Impact: Our study provides strong rationale for further investigations of other prostate cancer risk factors that may be distinctly associated with subtypes. Cancer Epidemiol Biomarkers Prev; 27(2); 193-200. ©2017 AACR.

Gene expression profiling of prostate tissue identifies chromatin regulation as a potential link between obesity and lethal prostate cancer

BACKGROUND

Obese men are at higher risk of advanced prostate cancer and cancer-specific mortality; however, the biology underlying this association remains unclear. This study examined gene expression profiles of prostate tissue to identify biological processes differentially expressed by obesity status and lethal prostate cancer.

METHODS

Gene expression profiling was performed on tumor (n = 402) and adjacent normal (n = 200) prostate tissue from participants in 2 prospective cohorts who had been diagnosed with prostate cancer from 1982 to 2005. Body mass index (BMI) was calculated from the questionnaire immediately preceding cancer diagnosis. Men were followed for metastases or prostate cancer-specific death (lethal disease) through 2011. Gene Ontology biological processes differentially expressed by BMI were identified using gene set enrichment analysis. Pathway scores were computed by averaging the signal intensities of member genes. Odds ratios (ORs) for lethal prostate cancer were estimated with logistic regression.

RESULTS

Among 402 men, 48% were healthy weight, 31% were overweight, and 21% were very overweight/obese. Fifteen gene sets were enriched in tumor tissue, but not normal tissue, of very overweight/obese men versus healthy-weight men; 5 of these were related to chromatin modification and remodeling (false-discovery rate < 0.25). Patients with high tumor expression of chromatin-related genes had worse clinical characteristics (Gleason grade > 7, 41% vs 17%; P = 2 × 10^-4 ) and an increased risk of lethal disease that was independent of grade and stage (OR, 5.26; 95% confidence interval, 2.37-12.25).

CONCLUSIONS

This study improves our understanding of the biology of aggressive prostate cancer and identifies a potential mechanistic link between obesity and prostate cancer death that warrants further study. Cancer 2017;123:4130-4138. © 2017 American Cancer Society.

Abstract 4740: Loss of the tumor suppressor zinc finger protein-36 and risk of lethal prostate cancer

Background. Biomarkers are needed to complement current clinicopathologic variables towards distinguishing prostate tumors that are likely to be metastatic from those that are indolent. We previously used a bioinformatic analytical approach to identify ZFP36, also known as Tristetraprolin (TTP), as a tumor suppressor in the NFκB pathway. The current study aims to evaluate the prognostic potential of tumor mRNA expression of ZFP36.

Methods. Our primary analysis leveraged data from a case-control study nested in the Health Professionals Follow-up Study and Physicians’ Health Study. Gene expression for ZFP36 was quantified from archival surgical tumor tissue using Affymetrix Human Gene 1.0 ST microarrays. Cases (n=113) were men who died of prostate cancer or developed metastatic disease, and controls (n=291) were men who lived at least 8 years after diagnosis and remained metastasis free. A genetically validated PTEN immunohistochemistry (IHC) assay was performed on tissue microarrays (TMAs) for a subset of the men (n=257).

Results. Mean ZFP36 expression was significantly lower in the cases compared to the controls (p&lt;0.001), and the crude odds ratio (OR) for lethal disease comparing those with low ZFP36 expression (below the lower quartile) to those with high ZFP36 expression (greater than or equal to the lower quartile) was 3.52 (95% CI: 2.18-5.69; p&lt;0.001). The association persisted with adjustment for Gleason category, age at diagnosis, and clinical stage, with an adjusted OR of 1.93 (95% CI: 1.07-3.49; p=0.03). When modeled as a continuous variable in a logistic regression for prognosis, ZFP36 improved the AUC of the clinical factor model (Gleason, age, and clinical stage) from 0.83 (95% CI: 0.79-0.88) to 0.85 (95% CI: 0.81-0.89; p=0.10 for improvement).

Among the patients with available PTEN staining, independent effects of ZFP36 and PTEN loss were observed. In the logistic regression on lethal disease with both variables included, PTEN negativity conferred an OR of 2.10 (95% CI: 1.11-3.93; p=0.02) and low ZFP36 produced an OR of 2.34 (95% CI: 1.24-4.36; p=0.01). Taken together, we observed an OR of 4.90 (95% CI: 2.05-11.72) comparing patients with PTEN negativity and low ZFP36 to those with PTEN staining present and high ZFP36.

Conclusions. Loss of the tumor suppressor ZFP36 is prognostic for metastatic or lethal prostate cancer. Combining information on ZFP36 with measurements from other mechanistic pathways, such as PTEN, may lead to highly accurate models.

Citation Format: Travis Gerke, Daniela Börnigen, Himisha Beltran, Svitlana Tyekucheva, Curtis Huttenhower, Gwo-Shu Lee, Bruce Trock, Lorelei Mucci, Christopher Sweeney. Loss of the tumor suppressor zinc finger protein-36 and risk of lethal prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4740. doi:10.1158/1538-7445.AM2017-4740

Abstract 4236: Gene expression profiling of prostate tissue identifies biological pathways associated with TMPRSS2:ERG gene fusion

Background: TMPRSS2:ERG, a hormonally regulated gene fusion present in about half of prostate tumors, is the most common somatic event in prostate cancer. There is intriguing evidence to suggest that TMPRSS2:ERG-positive tumors may define a distinct subgroup of prostate cancer. In this study we compared gene expression profiles according to fusion status to identify genes and biological pathways differential expressed by TMPRSS2:ERG.

Methods: The study included men with prostate cancer in the Health Professionals Follow-up Study and the Physicians’ Health Study diagnosed between 1982 and 2004 and followed through 2012. Tumor biomarker data was available for archival tumor tissue from 380 cases, 191 of whom also had gene expression data for adjacent normal tissue. Whole genome mRNA expression profiling (20,254 genes) was performed using the Affymetrix 1.0 ST array. TMPRSS2:ERG tumor status was assessed by a genetically validated IHC assay for ERG. To relate expression of individual genes to ERG we used linear regression. Gene Set Enrichment Analysis (GSEA) was used to identify pathways of genes associated with ERG in both tumor and adjacent normal tissue. Data from The Cancer Genome Atlas (TCGA) was used to validate these findings.

Results: Among 380 cases, 186 (49%) of tumors were positive for the gene fusion.

Genome-wide differential expression analysis identified 492 genes upregulated and 369 genes downregulated in tumor tissue comparing ERG+ to ERG- tumors (FDR p-value &lt; 0.05). No genes were identified in the adjacent normal tissue at this significance level. 772 of the 861 genes (90%) identified in the HPFS/PHS dataset were confirmed in TCGA (448 upregulated and 324 downregulated). The top ten genes included ERG, WNK2, CACNA1D, HES1, SEPT9, PLA2G7, TDRD1, ANTXR2, SORBS2, and MYO6. Enrichment analysis identified a number of metabolic pathways associated with ERG tumor status including pathways involved in amino acid and fatty acid metabolism.

Conclusions: We identified significant differences in gene expression profiles in prostate tumor tissue according to TMPRSS2:ERG status, providing supportive evidence of this fusion as a unique subtype.

Citation Format: Ericka Ebot, Masis Isikbay, Travis Gerke, Thomas U. Ahearn, Rachel S. Kelly, Svitlana Tyekucheva, Andreas Pettersson, Kathryn L. Penney, Lorelei A. Mucci. Gene expression profiling of prostate tissue identifies biological pathways associated with TMPRSS2:ERG gene fusion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4236. doi:10.1158/1538-7445.AM2017-4236

Abstract 5716: Tristetraprolin is a prognostic biomarker for biochemical recurrence in low Gleason score patients

PURPOSE: Most prostate cancer patients currently classified as having a low-risk of disease-specific death are overtreated in the United States, resulting in hundreds of thousands of men to have debilitating side effects from unnecessary treatment. However, ~30% of low-risk patients on active surveillance are later reclassified and require therapeutic intervention. Thus, there is a dire need for biomarkers that can discriminate which prostate tumors currently classified as low-risk will progress into aggressive disease.

EXPERIMENTAL DESIGN: Retrospective analyses of two independent prostate cancer expression datasets were performed to determine the relationship between the expression levels of the tumor suppressor Tristetraprolin (TTP, ZFP36) and biochemical recurrence (BCR). Further, TTP expression levels were measured by quantitative real-time PCR (qRT-PCR) in a cohort of prostate tumors from Moffitt Cancer Center patients having long-term follow-up (n=382), and will be correlated to associated clinical data, including BCR. Finally, the Cancer of the Prostate Risk Assessment Postsurgical (CAPRA-S) scores, a clinical tool used to predict prostate cancer outcomes following radical prostatectomy, were calculated along with BCR for the patients in one of the prostate cancer datasets.

RESULTS: Analysis of The Cancer Genome Atlas (TCGA) prostate adenocarcinoma dataset revealed that tumors with low TTP expression have an increased rate of BCR compared to those with high TTP levels (p=0.0096). Further, assessment of the GEO dataset GSE21034 (Taylor et al., Cancer Cell, 2010) established that prostate cancer patients with low Gleason scores (6 and 3+4) have an increased chance of BCR if their tumors express low levels of TTP compared to men with high TTP expressing tumors (p=0.0001). To validate these findings, patients with low Gleason score tumors and decreased levels of TTP in the Moffitt Cancer Center cohort are being analyzed to determine their rate of BCR. In contrast, CAPRA-S scores for low Gleason score tumors in the GSE20134 dataset failed to distinguish if a patient would have BCR (p=0.0511).

CONCLUSIONS: Prostate cancer patients with Gleason score 6 or 3+4, which are currently classified as having a low-risk of dying from prostate cancer, have an increased risk of BCR if their tumor expresses low levels of the tumor suppressor TTP. Our data suggests that TTP may be a biomarker that clearly discriminates which low Gleason score tumors will progress into aggressive disease.

Citation Format: Anders E. Berglund, Travis Gerke, Shivanshu Awasthi, G. Daniel Grass, Hyun Y. Park, John L. Cleveland, Jong Y. Park, Kosj Yamoah, Robert J. Rounbehler. Tristetraprolin is a prognostic biomarker for biochemical recurrence in low Gleason score patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5716. doi:10.1158/1538-7445.AM2017-5716