Transcriptomic Profiling of Primary Prostate Cancers and Nonlocalized Disease on Prostate-Specific Membrane Antigen Positron Emission Tomography/Computed Tomography: A Multicenter Retrospective Study.

PURPOSE: To characterize the relationship between Decipher genomic classifier scores and prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT)-based metastatic spread. MATERIALS AND METHODS: We identified patients from four institutions who underwent PSMA PET/CT scans pretreatment for primary staging or postradical prostatectomy (RP) for suspected recurrence and had Decipher transcriptomic data available from biopsy or RP specimens. PSMA PET/CT-based patterns of spread were classified as localized (miT + N0M0) or nonlocalized (miN1M0 or miM1a-c). We calculated the association between Decipher scores and the risk of nonlocalized disease on PSMA PET/CT using multivariable logistic regression for pretreatment patients and multivariable Cox regression for post-RP patients. We also compared select transcriptomic signatures between patients with localized and nonlocalized diseases. RESULTS: Five hundred eighty-six patients were included (pretreatment: n = 329; post-RP: n = 257). Higher Decipher scores were associated with nonlocalized disease on PSMA PET/CT both pretreatment (odds ratio, 1.18 [95% CI, 1.03 to 1.36] per 0.1 increase in Decipher score, P = .02) and post-RP (hazard ratio, 1.15 [95% CI, 1.05 to 1.27] per 0.1 increase in Decipher score, P = .003). In the pretreatment setting, nonlocalized disease was associated with higher rates of TP53 mutations and lower rates of PAM50 luminal A subtype compared with localized disease. In the post-RP setting, overexpression of signatures related to metabolism, DNA repair, and androgen receptor signaling were associated with higher rates of nonlocalized disease. CONCLUSION: Higher Decipher scores were associated with nonlocalized disease identified on PSMA PET/CT both pretreatment and post-RP. There were several transcriptomic differences between localized and nonlocalized diseases in both settings.

International Variations in Adherence to Quality Metrics for Locoregional Prostate Cancer.

BACKGROUND AND OBJECTIVE: Adherence to guideline recommendations can improve the quality of care for patients with prostate cancer (PCa). Our aim was to assess adherence to guidelines for locoregional PCa by international region. METHODS: The study cohort comprised patients diagnosed with locoregional PCa in the 10-country Movember TrueNTH Global Registry (n = 62 688; 2013-2022). We assessed adherence to four quality metrics: (1) active surveillance for low-risk PCa; (2) definitive treatment within 12 mo of diagnosis for unfavorable-risk PCa; (3) no staging imaging for favorable-risk PCa; and (4) staging imaging for unfavorable-risk PCa. For χ2 analyses, we combined the three most recent years of data entered by region for each outcome, with adjustment for multiple tests (p = 0.05 ÷ 4 = 0.0125). We also conducted multivariable logistic regression and temporal analyses. KEY FINDINGS AND LIMITATIONS: Active surveillance rates for low-risk PCa ranged from 85% in Australia/New Zealand (vs USA: adjusted odds ratio [aOR] 1.042, 95% confidence interval [CI] 0.740-1.520) to 14% in Central Europe (aOR 0.028, 95% CI 0.022-0.036). For patients with unfavorable-risk disease, the highest uptake rate for treatment within 12 mo of diagnosis was in Central Europe (98%; aOR 2.885, 95% CI 1.260-6.603), compared to 70% in Italy (aOR 0.031, 95%CI 0.014-0.072). The proportion of patients with favorable-risk disease who did not undergo imaging ranged from 94% in the USA to 30% in Italy (aOR 0.004, 95% CI 0.002-0.008), while the rate of imaging for unfavorable-risk PCa ranged from 8% in Hong Kong (aOR 65.222, 95% CI 43.676-97.398) to 39% in the USA (all χ2p < 0.0125). Regional temporal trends also varied. CONCLUSIONS AND CLINICAL IMPLICATIONS: In this international study comparing adherence to quality care metrics for the quality of care for locoregional PCa, we identified regional variance, possibly because of regional differences in cultural attitudes and health care structures. These benchmarks highlight opportunities for interventions to improve adherence to evidence-based guidelines. PATIENT SUMMARY: Our study shows that adherence to recommended management goals for patients with prostate cancer varies greatly by global region.

Risk Stratification of Patients with Recurrence After Primary Treatment for Prostate Cancer: A Systematic Review.

BACKGROUND AND OBJECTIVE: Biochemical recurrence (BCR) after primary definitive treatment for prostate cancer (PCa) is a heterogeneous disease state. While BCR is associated with worse oncologic outcomes, risk factors that impact outcomes can vary significantly, necessitating avenues for risk stratification. We sought to identify prognostic risk factors at the time of recurrence after primary radical prostatectomy or radiotherapy, and prior to salvage treatment(s), associated with adverse oncologic outcomes. METHODS: We performed a systematic review of prospective studies in EMBASE, MEDLINE, and ClinicalTrials.gov (from January 1, 2000 to October 16, 2023) according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines (CRD42023466330). We reviewed the factors associated with oncologic outcomes among patients with BCR after primary definitive treatment. KEY FINDINGS AND LIMITATIONS: A total of 37 studies were included (total n = 10 632), 25 after prostatectomy (total n = 9010) and 12 after radiotherapy (total n = 1622). Following recurrence after prostatectomy, factors associated with adverse outcomes include higher pathologic T stage and grade group, negative surgical margins, shorter prostate-specific antigen doubling time (PSADT), higher prostate-specific antigen (PSA) prior to salvage treatment, shorter time to recurrence, the 22-gene tumor RNA signature, and recurrence location on molecular imaging. After recurrence following radiotherapy, factors associated with adverse outcomes include a shorter time to recurrence, and shorter PSADT or higher PSA velocity. Grade group, T stage, and prior short-term hormone therapy (4-6 mo) were not clearly associated with adverse outcomes, although sample size and follow-up were generally limited compared with postprostatectomy data. CONCLUSIONS AND CLINICAL IMPLICATIONS: This work highlights the recommendations and level of evidence for risk stratifying patients with PCa recurrence, and can be used as a benchmark for personalizing salvage treatment based on prognostics. PATIENT SUMMARY: We summarize the data from previously reported clinical trials on the topic of which factors predict worse cancer outcomes for patients who recur with prostate cancer after their initial treatment.

Impact of PSMA PET on Prostate Cancer Management.

OPINION STATEMENT: PSMA-PET has been a practice-changing imaging biomarker for the management of men with PCa. Research suggests improved accuracy over conventional imaging and other PET radiotracers in many contexts. With multiple approved PSMA-targeting radiotracers, PSMA PET will become even more available in clinical practice. Its increased use requires an understanding of the prospective data available and caution when extrapolating from prior trial data that utilized other imaging modalities. Future trials leveraging PSMA PET for treatment optimization and management decision-making will ultimately drive its clinical utility.

A novel prostate cancer subtyping classifier based on luminal and basal phenotypes.

BACKGROUND: Prostate cancer (PCa) is a clinically heterogeneous disease. The creation of an expression-based subtyping model based on prostate-specific biological processes was sought. METHODS: Unsupervised machine learning of gene expression profiles from prospectively collected primary prostate tumors (training, n = 32,000; evaluation, n = 68,547) was used to create a prostate subtyping classifier (PSC) based on basal versus luminal cell expression patterns and other gene signatures relevant to PCa biology. Subtype molecular pathways and clinical characteristics were explored in five other clinical cohorts. RESULTS: Clustering derived four subtypes: luminal differentiated (LD), luminal proliferating (LP), basal immune (BI), and basal neuroendocrine (BN). LP and LD tumors both had higher androgen receptor activity. LP tumors also had a higher expression of cell proliferation genes, MYC activity, and characteristics of homologous recombination deficiency. BI tumors possessed significant interferon γactivity and immune infiltration on immunohistochemistry. BN tumors were characterized by lower androgen receptor activity expression, lower immune infiltration, and enrichment with neuroendocrine expression patterns. Patients with LD tumors had less aggressive tumor characteristics and the longest time to metastasis after surgery. Only patients with BI tumors derived benefit from radiotherapy after surgery in terms of time to metastasis (hazard ratio [HR], 0.09; 95% CI, 0.01-0.71; n = 855). In a phase 3 trial that randomized patients with metastatic PCa to androgen deprivation with or without docetaxel (n = 108), only patients with LP tumors derived survival benefit from docetaxel (HR, 0.21; 95% CI, 0.09-0.51). CONCLUSIONS: With the use of expression profiles from over 100,000 tumors, a PSC was developed that identified four subtypes with distinct biological and clinical features. PLAIN LANGUAGE SUMMARY: Prostate cancer can behave in an indolent or aggressive manner and vary in how it responds to certain treatments. To differentiate prostate cancer on the basis of biological features, we developed a novel RNA signature by using data from over 100,000 prostate tumors-the largest data set of its kind. This signature can inform patients and physicians on tumor aggressiveness and susceptibilities to treatments to help personalize cancer management.

Multimodality Therapies for Localized Prostate Cancer.

PURPOSE OF REVIEW: Multimodality therapy including radical prostatectomy, radiation therapy, and hormone therapy are frequently deployed in the management of localized prostate cancer. We sought to perform a critical appraisal of the most contemporary literature focusing on the multimodality management of localized prostate cancer. RECENT FINDINGS: Men who are ideal candidates for multimodality therapy include those with unfavorable intermediate-risk disease, high-risk disease, and very high-risk disease. Enhancements in both systemic agents (including second-generation antiandrogens) as well as localized therapies (such as stereotactic body radiotherapy and brachytherapy) are refining the optimal balance between the use of systemic and local therapies for localized prostate cancer. Genomic predictors are emerging as critical tools for more precisely allocating treatment intensification with multimodality therapies as well as treatment de-intensification. Close collaboration among medical oncologists, surgeons, and radiation oncologists will be critical for coordinating evidence-based multimodality therapies when clearly indicated and for supporting shared decision-making in areas where the evidence is mixed.

High intratumoral plasma cells content in primary prostate cancer defines a subset of tumors with potential susceptibility to immune-based treatments.

BACKGROUND: Data on advanced prostate cancer (PCa) suggest more prior systemic therapies might reduce tumor immune responsiveness. In treatment-naïve primary PCa, recent work correlated intratumoral plasma cell content with enhanced tumor immune-responsiveness. We sought to identify features of localized PCa at a high risk of recurrence following local treatment with high plasma cell content to help focus future immune-based neoadjuvant trials. METHODS: We performed retrospective analyses of molecular profiles from three independent cohorts of over 1300 prostate tumors. We used Wilcoxon Rank Sum to compare molecular pathways between tumors with high and low intratumoral plasma cell content and multivariable Cox proportional hazards regression analyses to assess metastasis-free survival. RESULTS: We validated an expression-based signature for intratumoral plasma cell content in 113 primary prostate tumors with both RNA-expression data and digital image quantification of CD138+ cells (plasma cell marker) based on immunohistochemisty. The signature showed castration-resistant tumors (n = 101) with more prior systemic therapies contained lower plasma cell content. In high-grade primary PCa, tumors with high plasma cell content were associated with increased predicted response to immunotherapy and decreased response to androgen-deprivation therapy. Master regulator analyses identified upregulated transcription factors implicated in immune (e.g. SKAP1, IL-16, and HCLS1), and B-cell activity (e.g. VAV1, SP140, and FLI-1) in plasma cell-high tumors. Master regulators overactivated in tumors with low plasma cell content were associated with shorter metastasis-free survival following radical prostatectomy. CONCLUSIONS: Markers of plasma cell activity might be leveraged to augment clinical trial targeting and selection and better understand the potential for immune-based treatments in patients with PCa at a high risk of recurrence following local treatment.

First-line Systemic Treatment of Recurrent Prostate Cancer After Primary or Salvage Local Therapy: A Systematic Review of the Literature.

CONTEXT: Several studies have investigated selection and sequencing of systemic agents to manage recurrent prostate cancer following local definitive treatment. OBJECTIVE: To define the incidence of recurrent prostate cancer in different countries, and systematically review management options and efficacy of first-line systemic therapies for patients with prostate cancer previously treated with definitive radical prostatectomy or radiation therapy. EVIDENCE ACQUISITION: We performed a systematic review of studies published from January 2010 to December 2021 in MEDLINE, EMBASE, or ClinicalTrials.gov according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Quality was assessed using the Grades of Recommendation, Assessment, Development and Evaluation methodology. The potential regional burdens of recurrent prostate cancer were estimated by analyzing various regional registry data. EVIDENCE SYNTHESIS: A total of 40 studies met the inclusion criteria and an additional landmark study published after the query was included in this review. Patients with metastatic recurrent disease derive benefit from the addition of androgen receptor signaling inhibitors to androgen deprivation therapy, while docetaxel should be reserved for patients with a high-volume metastatic burden by conventional imaging. Patients with biochemical-only recurrent disease benefit from continuous or intermittent androgen deprivation therapy if they possess high-risk features such as short prostate-specific antigen doubling time or high serum prostate-specific antigen. Current limitations to the published literature include no consideration of contemporary positron emission tomography imaging for evaluating metastatic recurrence or burden and few quality of life assessments. CONCLUSIONS: This systematic review summarizes the findings and recommendations for first-line systemic therapy for patients with recurrent prostate cancer following local therapy. PATIENT SUMMARY: We performed a systematic evaluation and summary of all studies published within the past decade on the topic of medications used to treat prostate cancer after it has recurred following radiation therapy or surgery. This review can be used to inform guidelines for prostate cancer management.

Association of B7-H3 expression with racial ancestry, immune cell density, and androgen receptor activation in prostate cancer.

BACKGROUND: B7 homolog 3 (B7-H3) is an immunomodulatory molecule that is highly expressed in prostate cancer (PCa) and belongs to the B7 superfamily, which includes PD-L1. Immunotherapies (antibodies, antibody-drug conjugates, and chimeric antigen receptor T cells) targeting B7-H3 are currently in clinical trials; therefore, elucidating the molecular and immune microenvironment correlates of B7-H3 expression may help to guide trial design and interpretation. The authors tested the interconnected hypotheses that B7-H3 expression is associated with genetic racial ancestry, immune cell composition, and androgen receptor signaling in PCa. METHODS: An automated, clinical-grade immunohistochemistry assay was developed by to digitally quantify B7-H3 protein expression across 2 racially diverse cohorts of primary PCa (1 with previously reported transcriptomic data) and pretreatment and posttreatment PCa tissues from a trial of intensive neoadjuvant hormonal therapy. RESULTS: B7-H3 protein expression was significantly lower in self-identified Black patients and was inversely correlated with the percentage African ancestry. This association with race was independent of the significant association of B7-H3 protein expression with ERG/ETS and PTEN status. B7-H3 messenger RNA expression, but not B7-H3 protein expression, was significantly correlated with regulatory (FOXP3-positive) T-cell density. Finally, androgen receptor activity scores were significantly correlated with B7-H3 messenger RNA expression, and neoadjuvant intensive hormonal therapy was associated with a significant decrease in B7-H3 protein expression. CONCLUSIONS: The current data underscore the importance of studying racially and molecularly diverse PCa cohorts in the immunotherapy era. This study is among the first to use genetic ancestry markers to add to the emerging evidence that PCa in men of African ancestry may have a distinct biology associated with B7-H3 expression. LAY SUMMARY: B7-H3 is an immunomodulatory molecule that is highly expressed in prostate cancer and is under investigation in clinical trials. The authors determined that B7-H3 protein expression is inversely correlated with an individual's proportion of African ancestry. The results demonstrate that B7-H3 messenger RNA expression is correlated with the density of tumor T-regulatory cells. Finally, in the first paired analysis of B7-H3 protein expression before and after neoadjuvant intensive hormone therapy, the authors determined that hormone therapy is associated with a decrease in B7-H3 protein levels, suggesting that androgen signaling may positively regulate B7-H3 expression. These results may help to guide the design of future clinical trials and to develop biomarkers of response in such trials.

Inflammatory bowel disease induces inflammatory and pre-neoplastic changes in the prostate.

BACKGROUND: Inflammatory bowel disease (IBD) has been implicated as a risk factor for prostate cancer, however, the mechanism of how IBD leads to prostate tumorigenesis is not known. Here, we investigated whether chronic intestinal inflammation leads to pro-inflammatory changes associated with tumorigenesis in the prostate. METHODS: Using clinical samples of men with IBD who underwent prostatectomy, we analyzed whether prostate tumors had differences in lymphocyte infiltrate compared to non-IBD controls. In a mouse model of chemically-induced intestinal inflammation, we investigated whether chronic intestinal inflammation could be transferred to the wild-type mouse prostate. In addition, mouse prostates were evaluated for activation of pro-oncogenic signaling and genomic instability. RESULTS: A higher proportion of men with IBD had T and B lymphocyte infiltration within prostate tumors. Mice with chronic colitis showed significant increases in prostatic CD45 + leukocyte infiltration and elevation of three pro-inflammatory cytokines-TIMP-1, CCL5, and CXCL1 and activation of AKT and NF-kB signaling pathways. Lastly, mice with chronic colitis had greater prostatic oxidative stress/DNA damage, and prostate epithelial cells had undergone cell cycle arrest. CONCLUSIONS: These data suggest chronic intestinal inflammation is associated with an inflammatory-rich, pro-tumorigenic prostatic phenotype which may explain how gut inflammation fosters prostate cancer development in men with IBD.

A transcriptomic model for homologous recombination deficiency in prostate cancer.

BACKGROUND: Tumors with mutations associated with homologous recombination deficiency (HRD) are uncommon in prostate cancer (PCa) and variably responsive to PARP inhibition. To better identify tumors with HRD, we developed a transcriptomic signature for HRD in PCa (HRD-P). METHODS: By using an established mutational signature, we created and validated HRD-P in six independent PCa cohorts (primary PCa, n = 8224; metastatic castration-resistant PCa [mCRPC], n = 328). Molecular and clinical features were compared between HRD-P+ tumors and those with single HR-gene mutations. RESULTS: HRD-P+ tumors were more common than tumors with single HR-gene mutations in primary (201/491, 41% vs 32/491 6.5%) and mCRPC (126/328, 38% vs 82/328, 25%) cases, and HRD-P+ was more predictive of genomic instability suggestive of HRD. HRD-P+ was associated with a shorter time to recurrence following surgery and shorter overall survival in men with mCRPC. In a prospective trial of mCRPC treated with olaparib (n = 10), all three men with HRD-P+ experienced prolonged (>330 days) PSA progression-free survival. CONCLUSION: These results suggest transcriptomics can identify more patients that harbor phenotypic HRD than single HR-gene mutations and support further exploration of transcriptionally defined HRD tumors perhaps in conjunction with genomic markers for therapeutic application.

It's all in the name: Does nomenclature for indolent prostate cancer impact management and anxiety?

BACKGROUND: Despite consensus guidelines, many men with low-grade prostate cancer are not managed with active surveillance. Patient perception of the nomenclature used to describe low-grade prostate cancers may partly explain this discrepancy. METHODS: A randomized online survey was administered to men without a history of prostate cancer, presenting a hypothetical clinical scenario in which they are given a new diagnosis of low-grade prostate cancer. The authors determined whether diagnosis nomenclature was associated with management preference and diagnosis-related anxiety using ratings given on a scale from 1 to 100, adjusting for participant characteristics through multivariable linear regression. RESULTS: The survey was completed by 718 men. Compared with Gleason 6 out of 10 prostate cancer, the term grade group 1 out of 5 prostate cancer was associated with lower preference for immediate treatment versus active surveillance (ß = -9.3; 95% CI, -14.4, -4.2; P < .001), lower diagnosis-related anxiety (ß = -8.3; 95% CI, -12.8, -3.8; P < .001), and lower perceived disease severity (ß = -12.3; 95% CI, -16.5, -8.1; P < .001) at the time of initial diagnosis. Differences decreased as participants received more disease-specific education. Indolent lesion of epithelial origin, a suggested alternative term for indolent tumors, was not associated with differences in anxiety or preference for active surveillance. CONCLUSIONS: Within a hypothetical clinical scenario, nomenclature for low-grade prostate cancer affects initial perception of the disease and may alter subsequent decision making, including preference for active surveillance. Disease-specific education reduces the differential impact of nomenclature use, reaffirming the importance of comprehensive counseling and clear communication between the clinician and patient.

A PRC2-independent function for EZH2 in regulating rRNA 2'-O methylation and IRES-dependent translation.

Dysregulated translation is a common feature of cancer. Uncovering its governing factors and underlying mechanism are important for cancer therapy. Here, we report that enhancer of zeste homologue 2 (EZH2), previously known as a transcription repressor and lysine methyltransferase, can directly interact with fibrillarin (FBL) to exert its role in translational regulation. We demonstrate that EZH2 enhances rRNA 2'-O methylation via its direct interaction with FBL. Mechanistically, EZH2 strengthens the FBL-NOP56 interaction and facilitates the assembly of box C/D small nucleolar ribonucleoprotein. Strikingly, EZH2 deficiency impairs the translation process globally and reduces internal ribosome entry site (IRES)-dependent translation initiation in cancer cells. Our findings reveal a previously unrecognized role of EZH2 in cancer-related translational regulation.

Efficacy and Adverse Events of Docetaxel for Metastatic, Hormone-sensitive Prostate Cancer Among Elderly Men: A Post Hoc Analysis of the CHAARTED Trial.

BACKGROUND: Combination therapy with docetaxel and androgen deprivation therapy (ADT) prolongs overall survival (OS) in men with metastatic hormone-sensitive prostate cancer. We assessed the benefits and adverse effects of docetaxel and ADT in relation to advancing age. METHODS: We performed a post hoc analysis of the CHAARTED trial comparing docetaxel and ADT vs. ADT alone (n = 773). Patients were stratified in age groups <60, 60-70, and >70 years old. Multivariable-adjusted progression-free survival (PFS) and OS were assessed using Kaplan-Meier curves and compared using multivariable Cox regressions with calculated interaction terms between age group and treatment arm. In the combination arm, the incidence of ≥1 adverse event (grade ≥3) and the number of adverse events per patient were compared for each age group using multivariable logistic and linear regressions, respectively. RESULTS: After adjusting for clinical variables, docetaxel's effect did not vary by age group for PFS and OS. There was no significant difference in the odds ratio of ≥1 adverse event (P > .1 for age groups 60-70 and >70 years old compared with <60 years old). However, men age >70 years old experienced +0.37 more adverse events per patient compared with men age <60 years old (95% CI, 0.11-0.64; P = .006). CONCLUSIONS: PFS and OS were similar across age groups for the combination of docetaxel and ADT compared with ADT. Older men experienced a modest increase in adverse events per patient, highlighting the importance of balancing treatment benefits and adverse effects in this age group.

Cause of death during prostate cancer survivorship: A contemporary, US population-based analysis.

BACKGROUND: More than 3.6 million men in the United States harbor a diagnosis of prostate cancer (PCa). The authors sought to provide in-depth analyses of the causes of death for contemporary survivors. METHODS: The authors performed a population-based cohort study in the United States (2000-2016) to assess causes of death for men diagnosed with PCa stratified by demographics and tumor stage. Using general population data, they calculated standardized mortality ratios (SMRs) as observed-to-expected death ratios. RESULTS: In total, 752,092 men with PCa, including 200,302 who died (27%), were assessed. A total of 29,048 men with local/regional disease (17%) died of PCa, whereas more than 4-fold men died of other causes (n = 143,719 [83%]). SMRs for death from noncancer causes (0.77; 95% confidence interval [CI], 0.77-0.78) suggested that these men were less likely than the general population to die of most other causes. The most common noncancer cause of death was cardiac-related (23%; SMR, 0.76; 95% CI, 0.75-0.77). Among men with distant PCa, 90% of deaths occurred within 5 years of diagnosis. Although deaths due to PCa composed the majority of deaths (74%), SMRs suggested that men with distant PCa were at heightened risk for death from most other noncancer causes (1.50; 95% CI, 1.46-1.54) and, in particular, for cardiac-related death (SMR, 1.48; 95% CI, 1.41-1.54) and suicide (SMR, 2.32; 95% CI, 1.78-2.96). Further analyses demonstrated that causes of death varied by patient demographics. CONCLUSIONS: Causes of death during PCa survivorship vary by patient and tumor characteristics. These data provide valuable information regarding health care prioritization during PCa survivorship. LAY SUMMARY: Men with early-stage prostate cancer are 4-fold more likely to die of other causes, whereas those with advanced prostate cancer are at increased risk for several causes not related to prostate cancer in comparison with the general population. These findings can help guide physicians taking care of men with a diagnosis of prostate cancer.

Plasma cells are enriched in localized prostate cancer in Black men and are associated with improved outcomes.

Black men die more often of prostate cancer yet, interestingly, may derive greater survival benefits from immune-based treatment with sipuleucel-T. Since no signatures of immune-responsiveness exist for prostate cancer, we explored race-based immune-profiles to identify vulnerabilities. Here we show in multiple independent cohorts comprised of over 1,300 patient samples annotated with either self-identified race or genetic ancestry, prostate tumors from Black men or men of African ancestry have increases in plasma cell infiltrate and augmented markers of NK cell activity and IgG expression. These findings are associated with improved recurrence-free survival following surgery and nominate plasma cells as drivers of prostate cancer immune-responsiveness.

Somatic HOXB13 Expression Correlates with Metastatic Progression in Men with Localized Prostate Cancer Following Radical Prostatectomy.

BACKGROUND: Homeobox B13 (HOXB13) expression regulates normal prostate development and mutations are associated with prostate cancer (PCa) formation. OBJECTIVE: To assess the role of HOXB13 mRNA expression in PCa progression following radical prostatectomy. DESIGN, SETTING, AND PARTICIPANTS: Genome-wide expression profiles were queried from two retrospective prostatectomy cohorts with follow-up data (Mayo Clinic, n=780; Johns Hopkins Medical Institute [JHMI], n=355), and a prospective genomic registry (n=5239). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Multivariable Cox regressions were used to analyze metastasis-free survival (MFS). RESULTS AND LIMITATIONS: HOXB13 expression in primary PCa increased with increasing tumor grade and with high metastatic potential based on a genomic signature. The highest quartile of HOXB13 expression was associated with worse MFS compared with the lowest quartile (Mayo Clinic: adjusted hazard ratio [AHR] 1.46, 95% confidence interval [CI] 1.03-2.06, and JHMI: AHR 1.80, 95% CI 1.02-3.19). The combinations of high HOXB13 expression and low expression of its binding partner, MEIS1 (AHR 2.03, 95% CI 1.54-2.66) or MEIS2 (AHR 1.73, 95% CI 1.33-2.26), portended worse MFS. Additionally, high HOXB13 expression in combination with low MEIS1/2 expression correlated with high expression of androgen receptor-mediated genes. The retrospective nature of this study subjects the findings to a bias due to unmeasured variables. CONCLUSIONS: Primary PCa tumors with increased HOXB13 expression have an increased propensity for metastases following prostatectomy, particularly in the setting of low MEIS1/2 expression. High androgen receptor output may account for worse outcomes for these tumors and suggests heightened sensitivity to androgen suppression. PATIENT SUMMARY: Using genomic data from a large number of prostate cancer (PCa) tumors, we found that increased expression of homeobox B13 (HOXB13), a gene related to normal prostate development, was associated with worse outcomes following surgery for PCa. A biomarker signature suggests that these tumors would be more susceptible to androgen suppression, a common treatment for PCa. Take Home Messagece:: In multiple large cohorts, prostate cancer tumors with high homeobox B13 (HOXB13) expression and low expression of its binding partner MEIS1/2 were enriched with high androgen receptor output and had an increased propensity for metastases following surgery.