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Early indicators of metastatic cancer response to therapy are important for evaluating new drugs and stopping ineffective treatment. The RECIST guidelines based on repeat cancer imaging are widely adopted in clinical trials, are used to identify active regimens that may change practice, and contribute to regulatory approvals. However, these criteria do not provide insight before 6 to 12 weeks of treatment and typically require that patients have measurable disease. Recent data suggest that measuring on-treatment changes in the amount or proportion of ctDNA in peripheral blood plasma may accurately identify responding and nonresponding cancers at earlier time points. Over the past year, the RECIST working group has evaluated current evidence for plasma ctDNA kinetics as a treatment response biomarker in metastatic cancers and early endpoint in clinical trials to identify areas of focus for future research and validation. Here, we outline the requirement for large standardized trial datasets, greater scrutiny of optimal ctDNA collection time points and assay thresholds, and consideration of regulatory body guidelines and patient opinions. In particular, clinically meaningful changes in plasma ctDNA abundance are likely to differ by cancer type and therapy class and must be assessed before ctDNA can be considered a potential pan-cancer response evaluation biomarker. Despite the need for additional data, minimally invasive on-treatment ctDNA measurements hold promise to build upon existing response assessments such as RECIST and offer opportunities for developing novel early endpoints for modern clinical trials., (©2024 American Association for Cancer Research.)

Purpose: Programmed death-ligand 1 (PD-L1) is overexpressed by dendritic cells in patients with metastatic castration-resistant prostate cancer (mCRPC) progressing on androgen receptor pathway inhibitors. We tested whether checkpoint blockade could enhance antitumor activity in mCRPC., Methods: In a multicenter open-label non-comparative randomized phase II study, patients with mCRPC treated with £ 1 prior cytotoxic chemotherapy, with measurable disease and progression on abiraterone and/or enzalutamide were randomized to durvalumab (D) 1500mg IV Q4 weeks ± 4 doses of tremelimumab (T) 75mg IV. The primary endpoint was objective response (OR) by iRECIST using a Simon 2-stage design. Correlative testing included PD-L1/CD8 immunohistochemistry on baseline tumour biopsies and deep targeted sequencing of plasma cell-free DNA., Results: 52 patients were enrolled. Median age was 70 years (range, 50-83 years) and 52% had prior taxane therapy for mCRPC. In stage 1, 13 patients were randomized to D with no OR observed. D+T advanced to stage 2 with 39 patients enrolled (receiving a median 3 cycles, range 1-53). D+T related adverse events (AEs) were mainly £ grade 2 but led to discontinuation in 7 patients . There were seven OR (19.4% [95% confidence interval: 8.2-36.0%]; intention to treat (ITT) 17.9% [95% confidence interval: 7.5-33.5%]). Five responding tumours were PD-L1 positive and two exhibited DNA damage repair defects. Responses were observed without high tumour mutational burden or other genomic indices of immunotherapy sensitivity., Conclusion: D+T is active in mCRPC but patient selection remains a challenge. Further studies to develop predictive biomarkers are warranted.

Bladder cancer (BCa) poses a significant health challenge, particularly affecting men with higher incidence and mortality rates. Addressing the need for improved predictive models in BCa treatment, this study introduces an innovative 3D in vitro patient-derived bladder cancer tumor model, utilizing decellularized pig bladders as scaffolds. Traditional 2D cell cultures, insufficient in replicating tumor microenvironments, have driven the development of sophisticated 3D models. The study successfully achieved pig bladder decellularization through multiple cycles of immersion in salt solutions, resulting in notable macroscopic and histological changes. This process confirmed the removal of cellular components while preserving the native extracellular matrix (ECM). Quantitative analysis demonstrated the efficacy of decellularization, with a remarkable reduction in DNA concentration, signifying the removal of over 95% of cellular material. In the development of the in vitro bladder cancer model, muscle invasive bladder cancer patients' cells were cultured within decellularized pig bladders, yielding a three-dimensional cancer model. Optimal results were attained using an air-liquid interface technique, with cells injected directly into the scaffold at three distinct time points. Histological evaluations showcased characteristics resembling in vivo tumors derived from bladder cancer patients' cells. To demonstrate the 3D cancer model's effectiveness as a drug screening platform, the study treated it with Cisplatin (Cis), Gemcitabine (Gem), and a combination of both drugs. Comprehensive cell viability assays and histological analyses illustrated changes in cell survival and proliferation. The model exhibited promising correlations with clinical outcomes, boasting an 83.3% reliability rate in predicting treatment responses. Comparison with traditional 2D cultures and spheroids underscored the 3D model's superiority in reliability, with an 83.3% predictive capacity compared to 50% for spheroids and 33.3% for 2D culture. Acknowledging limitations, such as the absence of immune and stromal components, the study suggests avenues for future improvements. In conclusion, this innovative 3D bladder cancer model, combining decellularization and patient-derived cells, marks a significant advancement in preclinical drug testing. Its potential for predicting treatment outcomes and capturing patient-specific responses opens new avenues for personalized medicine in bladder cancer therapeutics. Future refinements and validations with larger patient cohorts hold promise for revolutionizing BCa research and treatment strategies., (© 2024. The Author(s).)

Purpose: Indolent prostate cancer (PCa) is prevalent in the intended use population (adults age 50-79 years) for blood-based multicancer early detection (MCED) tests. We examined the detectability of PCa by a clinically validated, targeted methylation-based MCED test., Methods: Detectability by Gleason grade group (GG), clinical stage, association of detection status with tumor methylated fraction (TMeF), and overall survival (OS) were assessed in substudy 3 of Circulating Cell-Free Genome Atlas (CCGA; ClinicalTrials.gov identifier: NCT02889978) and PATHFINDER (ClinicalTrials.gov identifier: NCT04241796) studies., Results: Test sensitivity for PCa in substudy 3 of CCGA was 11.2% (47/420). The test detected 0 (0%) of 58 low-grade (GG1), 3 (1.9%) of 157 favorable intermediate-grade (GG2), 4 (5.1%) of 78 unfavorable intermediate-grade (GG3), and 36 (31.9%) of 113 high-grade (GG4 and 5) cancers and 3 (3.2%) of 95 stage I, 11 (4.7%) of 235 stage II, 7 (14.9%) of 47 stage III, and 22 (81.5%) of 27 stage IV cases. The median TMeF was higher for detected than nondetected cases (2,106.0 parts per million [PPM]; IQR, 349.8-24,376.3 v 24.4 PPM; IQR, 17.8-38.5; P < .05). Nondetected cases had better OS ( P < .05; hazard ratio [HR], 0.263 [95% CI, 0.104 to 0.533]) and detected cases had similar survival ( P = .2; HR, 0.672 [95% CI, 0.323 to 1.21]) compared with SEER adjusted for age, GG, and stage. Performance was similar in PATHFINDER, with no detected GG1/2 (0/13) or stage I/II (0/16) cases., Conclusion: This MCED test preferentially detects high-grade, clinically significant PCa. Use in population-based screening programs in addition to standard-of-care screening is unlikely to exacerbate overdiagnosis of indolent PCa.

The impact of variations in the three-dimensional structure of the genome has been recognized, but solid cancer tissue studies are limited. Here, we performed integrated deep Hi-C sequencing with matched whole-genome sequencing, whole-genome bisulfite sequencing, 5-hydroxymethylcytosine (5hmC) sequencing and RNA sequencing across a cohort of 80 biopsy samples from patients with metastatic castration-resistant prostate cancer. Dramatic differences were present in gene expression, 5-methylcytosine/5hmC methylation and in structural variation versus mutation rate between A and B (open and closed) chromatin compartments. A subset of tumors exhibited depleted regional chromatin contacts at the AR locus, linked to extrachromosomal circular DNA (ecDNA) and worse response to AR signaling inhibitors. We also identified topological subtypes associated with stark differences in methylation structure, gene expression and prognosis. Our data suggested that DNA interactions may predispose to structural variant formation, exemplified by the recurrent TMPRSS2-ERG fusion. This comprehensive integrated sequencing effort represents a unique clinical tumor resource., (© 2024. The Author(s).)

Context: Prostate cancer is a molecularly heterogeneous disease that is amenable to diagnostic testing to identify patients potentially eligible for personalised treatments inform familial risk and provide relevant information about potential prognosis. Several guidelines support the integration of genomic testing in a shared decision-making framework so that both health care professionals (HCPs) and patients are involved in determining the best treatment approach., Objective: To review current guidelines on molecular diagnostic testing for homologous recombination repair (HRR) gene alterations in patients with metastatic prostate cancer, with the aim of providing practical considerations for effective guideline implementation and establishment of an appropriate pathway for molecular diagnostic testing., Evidence Acquisition: We undertook a nonsystematic narrative review of the literature using PubMed to identify current guidelines and recommendations on molecular diagnostic testing for BRCA and/or homologous recombination repair gene alterations (HRRm) in patients with prostate cancer. In addition, selected articles that included BRCA/HRRm testing in clinical trials in metastatic castration-resistant prostate cancer and real-world evidence were also evaluated. Websites for relevant societies were reviewed for molecular diagnostic guidelines not published on PubMed., Evidence Synthesis: Our review of guidelines published by several international societies that include molecular testing in prostate cancer identified variations in molecular testing approaches. The review of testing approaches used in clinical trials and real-world settings also highlighted several aspects that require improvement. Therefore, we compiled practical guidance for establishing an appropriate BRCA/HRR mutation testing pathway., Conclusions: While there are several challenges to molecular testing and interpretation of test results that require enhancement, a multidisciplinary team approach will empower HCPs and their institutions to improve on or initiate their own molecular testing pathways. This in turn will lead to improvements in management strategies for patients with metastatic prostate cancer, for whom better treatment outcomes is a significant unmet need., Patient Summary: Establishing a molecular testing pathway in clinical practice for patients with metastatic castration-resistant prostate cancer will lead to fairer and more equal access to personalised treatments. This should lead to better outcomes, particularly for patients whose disease has spread to other areas of the body., (Copyright © 2023 European Association of Urology. Published by Elsevier B.V. All rights reserved.)

Competing Interests: Scott Delacroix, Jared Foster, Francesca Khani, Joseph Liao, Abdul Tawab-Amiri Pamela West, Alex Wyatt: No conflicts. David McConkey: Editorial Board member of this journal, but was not involved in the peer-review process nor had access to any information regarding its peer-review. Grants and contracts – Department of Defense, Mark Foundation, Commonwealth Foundation. Brian Baumann: Consulting fees – Boston Scientific, Varian, Novartis, Blue Earth; leadership or fiduciary role – Board of Directors, National Association for Proton Therapy. Stephanie Cooper Greenberg: Patient advocate, Johns Hopkins Greenberg Bladder Cancer Institute and NCI’s Bladder Cancer Task Force. David DeGraff: Editorial Board member of this journal, but was not involved in the peer-review process nor had access to any information regarding its peer-review Grants and contracts – Bristol Myers Squibb, Department of Defense; receipt of material – Astra-Zeneca. Jason Efstathiou: Editorial Board member of this journal, but was not involved in the peer-review process nor had access to any information regarding its peer-review Consulting fees – Blue Earth Diagnostics, Boston Scientific, AstraZeneca, Genentech, Astellas/Pfizer, Lantheus; payment or honoraria – IBA, Elekta, UpToDate; advisory boards – Merck, Roivant Pharma, Myovant Sciences, Janssen, Bayer Healthcare, Progenics Pharmaceuticals, Pfizer, Astellas, Gilead, Lantheus, Blue Earth Diagnostics, Angiodynamics; committee leadership – Vice-Chair, GU Committee, NRG; Board member (unpaid) – Massachusetts Prostate Cancer Coalition (MPCC) American College of Radiation Oncology (ACRO), Radiation Oncology Institute (ROI). Susan Groshen: Financial support from NCI/GUSC for attending a 2-day workshop that led to the CTPM. Edward Kadel: Patent, “PD-L1 PROMOTER METHYLATION IN CANCER”; stock or stock options, 89bio, Apple, Amazon, Alphabet, Eli Lilly & Co, Inspire Medical Systems, Merck & Co, Roche, SPDR S&P Biotech ETF, Teladoc; employee of Genentech/Roche. William Kim: Editorial Board member of this journal, but was not involved in the peer-review process nor had access to any information regarding its peer-review. Grants or contracts – NIH R01-CA241810, Merck; consulting fees – Focal Medical (spouse); advisory board – OncoRev; stock or stock options – Abbvie, Amgen, Apellis, BeiGene, BMS, Lilly, ImmunityBio, Moderna, Natera, NovoNordisk, Revolution Medicines, Tango Therapeutics, Zentalis; other financial or non-financial interests – Focal Medical, ownership interest (spouse). Seth Lerner: Co-Editor-in-Chief of this journal, but was not involved in the peer-review process nor had access to any information regarding its peer-review. Advisory board – FerGene, Pfizer. BMS, Incyte; consultant – Vaxiion, Verity, Protara, C2i Genomics, Ferring, Aura Bioscience, Surge Therapeutics; clinical trials – Genentech (SWOG), Vaxiion, Endo, FKD, JBL (SWOG), Merck (Alliance), Aura Bioscience, Surge Therapeutics, QED Therapeutics; honoraria – UroToday, co-editor bladder cancer section UpToDate, Grand Rounds Urology; compensated editorial responsibilities – IOS Press. Trevor Levin: Grants or contracts – NCI SBIR 5R44CA200174-05; patents issued or pending – WO/2017/056451, WO/2020/023630, WO/2020/243587, WO/2022/216865A1; leadership or fiduciary role – Convergent Genomics (Executive and Board roles); stock or stock options – Convergent Genomics. Matthew Milowski: Editorial Board member of this journal, but was not involved in the peer-review process nor had access to any information regarding its peer-review. Consulting: Loxo/Lilly; payments or honoraria, Medscape, Research to Practice; other financial or non-financial interests: Co-Editor in Chief, Clinical Genitourinary Cancer, Elsevier. Joshua Meeks: grants or contracts, VA, NIH, Department of Defense; consulting fees, Merck, AstraZeneca, Incyte, Janssen, BMS, UroGen, Prokarium, Imvax, Pfizer, Seagen/Astellas, Ferring; payments, Olympus, AUA, UroToday, OncLive; advisory boards, Astra-Zeneca, Medscape. David Miyamoto: grant support from NIH and the Radiation Oncology Institute. Kent Mouw: consulting fees, EMD Serono, Pfizer, UroGen, Riva Therapeutics. Eugene Pietzak: participation in a Data Safety Monitoring Committee or Advisory Board, QED Pharmaceuticals, Merck, Janssen, Urogen; society leadership, Chair of the Program Committtee, 2024 BCAN Think Tank. David Solit: consulting fees from Pfizer, Fog Pharma, PaigeAI, BridgeBio, Scorpion Therapeutics, FORE Therapeutics, Function Oncology, Pyramid, and Elsie Biotechnologies, Inc.; participation on a Data Safety Monitoring Board for Rain Therapeutics; stock or stock options from Scorpion Therapeutics, FORE Therapeutics, Function Oncology, Pyramid, Elsie Biotechnologies, Inc. Debashish Sundi: grants or contracts from Janssen, consulting fees from Janssen. Sara Wobker: royalties – Wolters Kluwer; honoraria – College of American Pathologists, American Society of Clinical Pathology, USCAP; travel reimbursement – Kidney Cancer Society. Andrea Apolo: Editorial Board member of this journal, but was not involved in the peer-review process nor had access to any information regarding its peer-review. Peter Black: Editorial Board member of this journal, but was not involved in the peer-review process nor had access to any information regarding its peer-review. Consulting fees – AbbVie, AstraZeneca, Astellas, Bayer, BMS, Combat, EMD-Serono, Ferring, Janssen, Merck, Nonagen, Nanobot, NanOlogy, Pfizer, Photocure, Prokarium, Sumitomo, TerSera, Tolmar, Verity; payments – Janssen, TerSera, Bayer, Pfizer; patents issued or pending – Veracyte.

Clinical genomic testing of patient germline, tumor tissue, or plasma cell-free DNA can enable a personalized approach to cancer management and treatment. In prostate cancer (PCa), broad genotyping tests are now widely used to identify germline and/or somatic alterations in BRCA2 and other DNA damage repair genes. Alterations in these genes can confer cancer sensitivity to poly (ADP-ribose) polymerase inhibitors, are linked with poor prognosis, and can have potential hereditary cancer implications for family members. However, there is huge variability in genomic tests and reporting standards, meaning that for successful implementation of testing in clinical practice, end users must carefully select the most appropriate test for a given patient and critically interpret the results. In this white paper, we outline key pre- and post-test considerations for choosing a genomic test and evaluating reported variants, specifically for patients with advanced PCa. Test choice must be based on clinical context and disease state, availability and suitability of tumor tissue, and the genes and regions that are covered by the test. We describe strategies to recognize false positives or negatives in test results, including frameworks to assess low tumor fraction, subclonal alterations, clonal hematopoiesis, and pathogenic versus nonpathogenic variants. We assume that improved understanding among health care professionals and researchers of the nuances associated with genomic testing will ultimately lead to optimal patient care and clinical decision making.

No consensus strategies exist for prognosticating metastatic castration-resistant prostate cancer (mCRPC). Circulating tumor DNA fraction (ctDNA%) is increasingly reported by commercial and laboratory tests but its utility for risk stratification is unclear. Here, we intersect ctDNA%, treatment outcomes, and clinical characteristics across 738 plasma samples from 491 male mCRPC patients from two randomized multicentre phase II trials and a prospective province-wide blood biobanking program. ctDNA% correlates with serum and radiographic metrics of disease burden and is highest in patients with liver metastases. ctDNA% strongly predicts overall survival, progression-free survival, and treatment response independent of therapeutic context and outperformed established prognostic clinical factors. Recognizing that ctDNA-based biomarker genotyping is limited by low ctDNA% in some patients, we leverage the relationship between clinical prognostic factors and ctDNA% to develop a clinically-interpretable machine-learning tool that predicts whether a patient has sufficient ctDNA% for informative ctDNA genotyping (available online: https://www.ctDNA.org ). Our results affirm ctDNA% as an actionable tool for patient risk stratification and provide a practical framework for optimized biomarker testing., (© 2024. The Author(s).)

Background: The phase 3 CALGB 90203 (Alliance) trial evaluated neoadjuvant chemohormonal therapy for high-risk localized prostate cancer before radical prostatectomy. We dissected the molecular features of post-treated tumors with long-term clinical outcomes to explore mechanisms of response and resistance to chemohormonal therapy., Methods: We evaluated 471 radical prostatectomy tumors, including 294 samples from 166 patients treated with 6 cycles of docetaxel plus androgen deprivation therapy before radical prostatectomy and 177 samples from 97 patients in the control arm (radical prostatectomy alone). Targeted DNA sequencing and RNA expression of tumor foci and adjacent noncancer regions were analyzed in conjunction with pathologic changes and clinical outcomes., Results: Tumor fraction estimated from DNA sequencing was significantly lower in post-treated tumor tissues after chemohormonal therapy compared with controls. Higher tumor fraction after chemohormonal therapy was associated with aggressive pathologic features and poor outcomes, including prostate-specific antigen-progression-free survival. SPOP alterations were infrequently detected after chemohormonal therapy, while TP53 alterations were enriched and associated with shorter overall survival. Residual tumor fraction after chemohormonal therapy was linked to higher expression of androgen receptor-regulated genes, cell cycle genes, and neuroendocrine genes, suggesting persistent populations of active prostate cancer cells. Supervised clustering of post-treated high-tumor-fraction tissues identified a group of patients with elevated cell cycle-related gene expression and poor clinical outcomes., Conclusions: Distinct recurrent prostate cancer genomic and transcriptomic features are observed after exposure to docetaxel and androgen deprivation therapy. Tumor fraction assessed by DNA sequencing quantifies pathologic response and could be a useful trial endpoint or prognostic biomarker. TP53 alterations and high cell cycle transcriptomic activity are linked to aggressive residual disease, despite potent chemohormonal therapy., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

De novo metastatic prostate cancer is highly aggressive, but the paucity of routinely collected tissue has hindered genomic stratification and precision oncology. Here, we leveraged a rare study of surgical intervention in 43 de novo metastatic prostate cancers to assess somatic genotypes across 607 synchronous primary and metastatic tissue regions plus circulating tumor DNA. Intra-prostate heterogeneity was pervasive and impacted clinically relevant genes, resulting in discordant genotypes between select primary restricted regions and synchronous metastases. Additional complexity was driven by polyclonal metastatic seeding from phylogenetically related primary populations. When simulating clinical practice relying on a single tissue region, genomic heterogeneity plus variable tumor fraction across samples caused inaccurate genotyping of dominant disease; however, pooling extracted DNA from multiple biopsy cores before sequencing can rescue misassigned somatic genotypes. Our results define the relationship between synchronous treatment-sensitive primary and metastatic lesions in men with de novo metastatic prostate cancer and provide a framework for implementing genomics-guided patient management., (© 2024. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Background: CC-115, a dual mTORC1/2 and DNA-PK inhibitor, has promising antitumour activity when combined with androgen receptor (AR) inhibition in pre-clinical models., Methods: Phase 1b multicentre trial evaluating enzalutamide with escalating doses of CC-115 in AR inhibitor-naive mCRPC patients (n = 41). Primary endpoints were safety and RP2D. Secondary endpoints included PSA response, time-to-PSA progression, and radiographic progression., Results: Common adverse effects included rash (31.7% Grades 1-2 (Gr); 31.7% Gr 3), pruritis (43.9% Gr 1-2), diarrhoea (37% Gr 1-2), and hypertension (17% Gr 1-2; 9.8% Gr 3). CC-115 RP2D was 5 mg twice a day. In 40 evaluable patients, 80% achieved ≥50% reduction in PSA (PSA50), and 58% achieved ≥90% reduction in PSA (PSA90) by 12 weeks. Median time-to-PSA progression was 14.7 months and median rPFS was 22.1 months. Stratification by PI3K alterations demonstrated a non-statistically significant trend towards improved PSA50 response (PSA50 of 94% vs. 67%, p = 0.08). Exploratory pre-clinical analysis suggested CC-115 inhibited mTOR pathway strongly, but may be insufficient to inhibit DNA-PK at RP2D., Conclusions: The combination of enzalutamide and CC-115 was well tolerated. A non-statistically significant trend towards improved PSA response was observed in patients harbouring PI3K pathway alterations, suggesting potential predictive biomarkers of response to a PI3K/AKT/mTOR pathway inhibitor., Clinical Trial Registration: ClinicalTrials.gov identifier: NCT02833883., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: The isolation of cell-free DNA (cfDNA) from the bloodstream can be used to detect and analyze somatic alterations in circulating tumor DNA (ctDNA), and multiple cfDNA-targeted sequencing panels are now commercially available for Food and Drug Administration (FDA)-approved biomarker indications to guide treatment. More recently, cfDNA fragmentation patterns have emerged as a tool to infer epigenomic and transcriptomic information. However, most of these analyses used whole-genome sequencing, which is insufficient to identify FDA-approved biomarker indications in a cost-effective manner., Patients and Methods: We used machine learning models of fragmentation patterns at the first coding exon in standard targeted cancer gene cfDNA sequencing panels to distinguish between cancer and non-cancer patients, as well as the specific tumor type and subtype. We assessed this approach in two independent cohorts: a published cohort from GRAIL (breast, lung, and prostate cancers, non-cancer, n = 198) and an institutional cohort from the University of Wisconsin (UW; breast, lung, prostate, bladder cancers, n = 320). Each cohort was split 70%/30% into training and validation sets., Results: In the UW cohort, training cross-validated accuracy was 82.1%, and accuracy in the independent validation cohort was 86.6% despite a median ctDNA fraction of only 0.06. In the GRAIL cohort, to assess how this approach performs in very low ctDNA fractions, training and independent validation were split based on ctDNA fraction. Training cross-validated accuracy was 80.6%, and accuracy in the independent validation cohort was 76.3%. In the validation cohort where the ctDNA fractions were all <0.05 and as low as 0.0003, the cancer versus non-cancer area under the curve was 0.99., Conclusions: To our knowledge, this is the first study to demonstrate that sequencing from targeted cfDNA panels can be utilized to analyze fragmentation patterns to classify cancer types, dramatically expanding the potential capabilities of existing clinically used panels at minimal additional cost., Competing Interests: Disclosure KTH has a family member who is an employee of Epic Systems. MLB has a family member who is an employee of Luminex. SGZ reports unrelated patents licensed to Veracyte, and that a family member is an employee of Artera and holds stock in Exact Sciences. KTH, SGZ, and the University of Wisconsin have filed a provisional patent on the work herein. SMD reports consulting relationships with BMS, Oncternal therapeutics, Janssen R&D/J&J and a grant from Pfizer/Astellas/Medivation (the grant was submitted to Medivation, ultimately funded by Astellas and then moved to Pfizer). FYF reports personal fees from Janssen Oncology, Bayer, PFS Genomics, Myovant Sciences, Roivant Sciences, Astellas Pharma, Foundation Medicine, Varian, Bristol Myers Squibb (BMS), Exact Sciences, BlueStar Genomics, Novartis, and Tempus; other support from Serimmune and Artera outside the submitted work. Integrated DNA Technologies (IDT, Coralville, IA) assisted in a pilot project to assess the performance characteristics of the UW panel before purchase, but played no role in this study. All other authors have declared no conflicts of interest. Data Sharing Raw sequencing data from the GRAIL dataset are available at the European Genome Archive (Dataset ID EGAD00001005302). Our institutional protocol does not allow unrestricted public access to the raw sequencing data. Therefore, data sharing requests must be submitted to the University of Wisconsin-Madison for approval. For samples from the two clinical trials (NCT03090165, NCT03725761), these trials are still ongoing, and data sharing requests must be submitted to the trial organizers., (Published by Elsevier Ltd.)

Systemic targeted therapy in prostate cancer is primarily focused on ablating androgen signaling. Androgen deprivation therapy and second-generation androgen receptor (AR)-targeted therapy selectively favor the development of treatment-resistant subtypes of metastatic castration-resistant prostate cancer (mCRPC), defined by AR and neuroendocrine (NE) markers. Molecular drivers of double-negative (AR-/NE-) mCRPC are poorly defined. In this study, we comprehensively characterized treatment-emergent mCRPC by integrating matched RNA sequencing, whole-genome sequencing, and whole-genome bisulfite sequencing from 210 tumors. AR-/NE- tumors were clinically and molecularly distinct from other mCRPC subtypes, with the shortest survival, amplification of the chromatin remodeler CHD7, and PTEN loss. Methylation changes in CHD7 candidate enhancers were linked to elevated CHD7 expression in AR-/NE+ tumors. Genome-wide methylation analysis nominated Krüppel-like factor 5 (KLF5) as a driver of the AR-/NE- phenotype, and KLF5 activity was linked to RB1 loss. These observations reveal the aggressiveness of AR-/NE- mCRPC and could facilitate the identification of therapeutic targets in this highly aggressive disease., Significance: Comprehensive characterization of the five subtypes of metastatic castration-resistant prostate cancer identified transcription factors that drive each subtype and showed that the double-negative subtype has the worst prognosis., (©2023 The Authors; Published by the American Association for Cancer Research.)

Purpose: Androgen receptor pathway inhibitors (ARPI) are standard of care for treatment-naïve metastatic castration-resistant prostate cancer (mCRPC), but rapid resistance is common. Early identification of resistance will improve management strategies. We investigated whether changes in circulating tumor DNA (ctDNA) fraction during ARPI treatment are linked with mCRPC clinical outcomes., Experimental Design: Plasma cell-free DNA was collected from 81 patients with mCRPC at baseline and after 4 weeks of first-line ARPI treatment during two prospective multicenter observational studies (NCT02426333; NCT02471469). ctDNA fraction was calculated from somatic mutations in targeted sequencing and genome copy-number profiles. Samples were classified into detected versus undetected ctDNA. Outcome measurements were progression-free survival (PFS) and overall survival (OS). Nondurable treatment response was defined as PFS ≤6 months., Results: ctDNA was detected in 48/81 (59%) baseline and 29/81 (36%) 4-week samples. ctDNA fraction for samples with detected ctDNA was lower at 4 weeks versus baseline (median 5.0% versus 14.5%, P = 0.017). PFS and OS were shortest for patients with persistent ctDNA at 4 weeks (univariate HR, 4.79; 95% CI, 2.62-8.77 and univariate HR, 5.49; 95% CI, 2.76-10.91, respectively), independent of clinical prognostic factors. For patients exhibiting change from detected to undetected ctDNA by 4 weeks, there was no significant PFS difference versus patients with baseline undetected ctDNA. ctDNA change had a positive predictive value of 88% and negative predictive value of 92% for identifying nondurable responses., Conclusions: Early changes in ctDNA fraction are strongly linked to duration of first-line ARPI treatment benefit and survival in mCRPC and may inform early therapy switches or treatment intensification. See related commentary by Sartor, p. 2745., (©2023 American Association for Cancer Research.)

Competing Interests: Conflicts of interest The authors declare no conflicts of interest relating to this manuscript, as per the seminar article structure. The manuscript is an extended summary of an online seminar and therefore reflects presentations of already published work and details of already established clinical trials.

Significant progress has been made in genetic and genomic testing for prostate cancer across the disease spectrum. Molecular profiling is increasingly relevant for routine clinical management, fueled in part by advancements in testing technology and integration of biomarkers into clinical trials. In metastatic prostate cancer, defects in DNA damage response genes are now established predictors of benefit to US Food and Drug Administration-approved poly (ADP-ribose) polymerase inhibitors and immune checkpoint inhibitors, and trials are actively investigating these and other targeted treatment strategies in earlier disease states. Excitingly, opportunities for molecularly informed management beyond DNA damage response genes are also maturing. Germline genetic variants (eg, BRCA2 or MSH2/6 ) and polygenic germline risk scores are being investigated to inform cancer screening and active surveillance in at-risk carriers. RNA expression tests have recently gained traction in localized prostate cancer, enabling patient risk stratification and tailored treatment intensification via radiotherapy and/or androgen deprivation therapy for localized or salvage treatment. Finally, emerging minimally invasive circulating tumor DNA technology promises to enhance biomarker testing in advanced disease pending additional methodological and clinical validation. Collectively, genetic and genomic tests are rapidly becoming indispensable tools for informing the optimal clinical management of prostate cancer.

Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear receptor central in the regulation of key cellular processes including cell metabolism, tissue differentiation, and regulation of the immune system. PPARγ is required for normal differentiation of the urothelium and is thought to be an essential driver of the luminal subtype of bladder cancer. However, the molecular components that regulate PPARG gene expression in bladder cancer remain unclear. Here, we developed an endogenous PPARG reporter system in luminal bladder cancer cells and performed genome-wide CRISPR knockout screening to identify bona fide regulators of PPARG gene expression. Functional validation of the dataset confirmed GATA3, SPT6, and the cohesin complex components SMC1A, and RAD21, as permissive upstream positive regulators of PPARG gene expression in luminal bladder cancer. In summary, this work provides a resource and biological insights to aid our understanding of PPARG regulation in bladder cancer., Competing Interests: The authors declare no competing interests., (Crown Copyright © 2023.)

Specific classes of DNA damage repair (DDR) defect can drive sensitivity to emerging therapies for metastatic prostate cancer. However, biomarker approaches based on DDR gene sequencing do not accurately predict DDR deficiency or treatment benefit. Somatic alteration signatures may identify DDR deficiency but historically require whole-genome sequencing of tumour tissue. We assembled whole-exome sequencing data for 155 high ctDNA fraction plasma cell-free DNA and matched leukocyte DNA samples from patients with metastatic prostate or bladder cancer. Labels for DDR gene alterations were established using deep targeted sequencing. Per sample mutation and copy number features were used to train XGBoost ensemble models. Naive somatic features and trinucleotide signatures were associated with specific DDR gene alterations but insufficient to resolve each class. Conversely, XGBoost-derived models showed strong performance including an area under the curve of 0.99, 0.99 and 1.00 for identifying BRCA2, CDK12, and mismatch repair deficiency in metastatic prostate cancer. Our machine learning approach re-classified several samples exhibiting genomic features inconsistent with original labels, identified a metastatic bladder cancer sample with a homozygous BRCA2 copy loss, and outperformed an existing exome-based classifier for BRCA2 deficiency. We present DARC Sign (DnA Repair Classification SIGNatures); a public machine learning tool leveraging clinically-practical liquid biopsy specimens for simultaneously identifying multiple types of metastatic prostate cancer DDR deficiencies. We posit that it will be useful for understanding differential responses to DDR-directed therapies in ongoing clinical trials and may ultimately enable prospective identification of prostate cancers with phenotypic evidence of DDR deficiency., (© 2023. The Author(s).)

Background: High-risk non-muscle-invasive bladder cancer (NMIBC) is treated with bacillus Calmette-Guérin (BCG), but relapse is common. Improvement of patient outcomes requires better understanding of links between BCG resistance and genomic driver alterations., Objective: To validate the prognostic impact of common genomic alterations in NMIBC pretreatment and define somatic changes present in post-BCG relapses., Design, Setting, and Participants: We retrieved tumour tissues and outcomes for 90 patients with BCG-naive NMIBC initiating BCG monotherapy. Post-BCG tissue was available from 34 patients. All tissues underwent targeted sequencing of tumour and matched normal., Outcome Measurements and Statistical Analysis: Associations between clinical outcomes and genomics were determined using Cox proportional hazard models., Results and Limitations: Of the patients, 58% were relapse free at data cut-off, 24% had NMIBC recurrence, and 18% experienced muscle-invasive progression. The risk of relapse was associated with ARID1A mutation (hazard ratio [HR] = 2.00; p = 0.04) and CCNE1 amplification (HR = 2.61; p = 0.02). Pre- and post-BCG tumours shared truncal driver alterations, with mutations in TERT and chromatin remodelling genes particularly conserved. However, shifts in somatic profiles were common and clinically relevant alterations in FGFR3, PIK3CA, TSC1, and TP53 were temporally variable, despite apparent clonal prevalence at one time point. Limitations include the difficulty of resolving the relative impact of BCG therapy versus surgery on genomics at relapse and biopsy bias., Conclusions: Somatic hypermutation and alterations in CCNE1 and ARID1A should be incorporated into future models predicting NMIBC BCG outcomes. Changes in tumour genomics over time highlight the importance of recent biopsy when considering targeted therapies, and suggest that relapse after BCG is due to persisting and evolving precursor populations., Patient Summary: Changes in key cancer genes can predict bladder cancer relapse after treatment with bacillus Calmette-Guérin. Relapses after treatment can be driven by large-scale genetic changes within the cancer. These genetic changes help us understand how superficial bladder cancer can progress to be treatment resistant., (Copyright © 2021 European Association of Urology. Published by Elsevier B.V. All rights reserved.)

Plasma circulating tumor DNA (ctDNA) represents short fragments of tumor-derived DNA released into the bloodstream primarily from cancer cells undergoing apoptosis. In metastatic castration-resistant prostate cancer (mCRPC), characterizing genomic alterations in ctDNA identifies mutations, copy number alterations, and structural rearrangements with predictive and prognostic biomarker utility. These associations with clinical outcomes have resulted in ctDNA increasingly incorporated into routine clinical care. In this review, we summarize current and emerging applications for ctDNA analysis in metastatic prostate cancer, including outcome prediction, treatment selection, and characterization of treatment resistance. We also discuss potential pitfalls with interpreting ctDNA findings, namely false negatives arising from low tumor content and optimal assay design, including correction for clonal hematopoiesis of indeterminate potential and germline variants. Understanding the influence of these limitations on interpretation of ctDNA results is necessary to overcome barriers to clinical implementation. Nevertheless, as assay availability and technology continue to improve, recognizing both opportunities and shortcomings of ctDNA analysis will retain relevance with informing the implementation of precision-oncology initiatives for metastatic prostate cancer., Competing Interests: EMK reports consulting roles with Astellas Pharma, Janssen and Ipsen; honoraria from Astellas Pharma, Janssen, Ipsen and Research Review, and research funding from AstraZeneca (institutional), Merck (institutional) and Astellas Pharma (institutional). AWW reports commercial research grants from Janssen and ESSA Pharma, and honoraria from AstraZeneca, Astellas, Janssen, and Merck. KNC reports grants and personal fees from Astellas, AstraZeneca, Janssen, Merck, Novartis, Pfizer, Point Biopharma, Roche, and Sanofi. The handling editor AA declared a past co-authorship with the author KNC., (Copyright © 2022 Kwan, Wyatt and Chi.)

Background: Primary mediastinal nonseminoma germ cell tumors (PMNSGCT) are a subgroup of nonseminoma germ cell tumors (GCT) with poor prognosis. In this study, PMNSGCT-specific genomic landscape was analyzed and correlated with clinical outcomes., Methods: DNA was extracted and sequenced from 28 archival tumor tissue of patients with mediastinal GCT (3 seminoma and 25 nonseminoma). Overall survival (OS) and association with gene alterations were estimated using the Kaplan-Meier and univariate Cox regression methods., Results: Three patients (11%) had a karyotype XXY, 17/28 (61%) tumor samples presented chromosome 12p amplification. Somatic mutations were detected in 19/28 (68%) samples. The most frequently mutated genes were: TP53 (13/28; 46%), KIT (5/28; 18%), and KRAS (5/28; 18%). Deleterious TP53 alterations were associated with significantly reduced overall survival (HR: 7.16; P = .012)., Conclusions: TP53 alterations are common in PMNSGCT and are associated with reduced overall survival, potentially underlying the poor sensitivity to chemotherapy observed in these patients., (© The Author(s) 2022. Published by Oxford University Press.)

Analysis of DNA methylation is a valuable tool to understand disease progression and is increasingly being used to create diagnostic and prognostic clinical biomarkers. While conversion of cytosine to 5-methylcytosine (5mC) commonly results in transcriptional repression, further conversion to 5-hydroxymethylcytosine (5hmC) is associated with transcriptional activation. Here we perform the first study integrating whole-genome 5hmC with DNA, 5mC, and transcriptome sequencing in clinical samples of benign, localized, and advanced prostate cancer. 5hmC is shown to mark activation of cancer drivers and downstream targets. Furthermore, 5hmC sequencing revealed profoundly altered cell states throughout the disease course, characterized by increased proliferation, oncogenic signaling, dedifferentiation, and lineage plasticity to neuroendocrine and gastrointestinal lineages. Finally, 5hmC sequencing of cell-free DNA from patients with metastatic disease proved useful as a prognostic biomarker able to identify an aggressive subtype of prostate cancer using the genes TOP2A and EZH2, previously only detectable by transcriptomic analysis of solid tumor biopsies. Overall, these findings reveal that 5hmC marks epigenomic activation in prostate cancer and identify hallmarks of prostate cancer progression with potential as biomarkers of aggressive disease., Significance: In prostate cancer, 5-hydroxymethylcytosine delineates oncogene activation and stage-specific cell states and can be analyzed in liquid biopsies to detect cancer phenotypes. See related article by Wu and Attard, p. 3880., (©2022 The Authors; Published by the American Association for Cancer Research.)

Metastatic prostate cancer remains a major clinical challenge and metastatic lesions are highly heterogeneous and difficult to biopsy. Liquid biopsy provides opportunities to gain insights into the underlying biology. Here, using the highly sensitive enrichment-based sequencing technology, we provide analysis of 60 and 175 plasma DNA methylomes from patients with localized and metastatic prostate cancer, respectively. We show that the cell-free DNA methylome can capture variations beyond the tumor. A global hypermethylation in metastatic samples is observed, coupled with hypomethylation in the pericentromeric regions. Hypermethylation at the promoter of a glucocorticoid receptor gene NR3C1 is associated with a decreased immune signature. The cell-free DNA methylome is reflective of clinical outcomes and can distinguish different disease types with 0.989 prediction accuracy. Finally, we show the ability of predicting copy number alterations from the data, providing opportunities for joint genetic and epigenetic analysis on limited biological samples., (© 2022. The Author(s).)

Background: Genomic alterations to the androgen receptor (AR) are common in metastatic castration-resistant prostate cancer (mCRPC). AR copy number amplifications, ligand-binding domain missense mutations, and intronic structural rearrangements can all drive resistance to approved AR pathway inhibitors and their detection via tissue or liquid biopsy is linked to clinical outcomes. With an increasingly crowded treatment landscape, there is hope that AR genomic alterations can act as prognostic and/or predictive biomarkers to guide patient management., Methods: In this review, we evaluate the current evidence for AR genomic alterations as clinical biomarkers in mCRPC, focusing on correlative studies that have used plasma circulating tumor DNA to characterize AR genotype., Results: We highlight data that demonstrates the complexity of AR genotype within individual patients, and suggest that future studies should account for cancer clonal heterogeneity and variable tumor content in liquid biopsy samples. Given the potential for cooccurrence of multiple AR genomic alterations in the same or competing subclones of a patient, it is distinctly challenging to attribute blanket clinical significance to any individual alteration. This challenge is further complicated by the varied treatment exposures in contemporary patients, and the fact that AR genotype continues to evolve in the mCRPC setting across sequential lines of systemic therapy., Conclusions: As treatment access and liquid biopsy technology continues to improve, we posit that real-time measures of AR biology are likely to play a key role in emerging precision oncology strategies for metastatic prostate cancer., (© 2022 Wiley Periodicals LLC.)

Our ability to prognosticate the clinical course of patients with cancer has historically been limited to clinical, histopathological, and radiographic features. It has long been clear however, that these data alone do not adequately capture the heterogeneity and breadth of disease trajectories experienced by patients. The advent of efficient genomic sequencing has led to a revolution in cancer care as we try to understand and personalize treatment specific to patient clinico-genomic phenotypes. Within prostate cancer, emerging evidence suggests that tumor genomics (e.g., DNA, RNA, and epigenetics) can be utilized to inform clinical decision making. In addition to providing discriminatory information about prognosis, it is likely tumor genomics also hold a key in predicting response to oncologic therapies which could be used to further tailor treatment recommendations. Herein we review select literature surrounding the use of tumor genomics within the management of prostate cancer, specifically leaning toward analytically validated and clinically tested genomic biomarkers utilized in radiotherapy and/or adjunctive therapies given with radiotherapy., (© 2022 Wiley Periodicals LLC.)

Circulating tumour DNA (ctDNA) in blood plasma is an emerging tool for clinical cancer genotyping and longitudinal disease monitoring 1 . However, owing to past emphasis on targeted and low-resolution profiling approaches, our understanding of the distinct populations that comprise bulk ctDNA is incomplete 2-12 . Here we perform deep whole-genome sequencing of serial plasma and synchronous metastases in patients with aggressive prostate cancer. We comprehensively assess all classes of genomic alterations and show that ctDNA contains multiple dominant populations, the evolutionary histories of which frequently indicate whole-genome doubling and shifts in mutational processes. Although tissue and ctDNA showed concordant clonally expanded cancer driver alterations, most individual metastases contributed only a minor share of total ctDNA. By comparing serial ctDNA before and after clinical progression on potent inhibitors of the androgen receptor (AR) pathway, we reveal population restructuring converging solely on AR augmentation as the dominant genomic driver of acquired treatment resistance. Finally, we leverage nucleosome footprints in ctDNA to infer mRNA expression in synchronously biopsied metastases, including treatment-induced changes in AR transcription factor signalling activity. Our results provide insights into cancer biology and show that liquid biopsy can be used as a tool for comprehensive multi-omic discovery., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Despite years of slow progress, muscle invasive bladder cancer (MIBC) is finally entering the era of molecularly guided targeted therapy. However, tumor heterogeneity is high in MIBC and may impact treatment response and resistance. The objective of this review is to dissect recent insights into inter- and intratumor heterogeneity (ITH) in MIBC, with emphasis on the clinical implications of this heterogeneity for biomarker-driven strategies and the development of new therapies., Methods: A nonsystematic review was performed in PubMed and EMBASE using the terms "tumor heterogeneity" and "bladder cancer.", Results: Intertumor heterogeneity, as reflected by different clinical phenotypes in different patients, has been partially explained with next generation sequencing and other molecular profiling technologies. RNA-based molecular subtyping, for example, provides a classification of MIBC into distinct categories that can be used for further molecular analysis, biomarker discovery, risk stratification, and treatment selection. Molecular subtyping and specific genomic alterations, especially in DNA damage repair genes, may help explain why some patients respond better to systemic chemotherapy and immunotherapy. Conversely, spatial and temporal ITH threaten to confound attempts to target specific molecular lesions since not all tumor cells within a patient may carry the relevant lesion. Improved understanding and management of ITH is required for the most effective use of biomarker-driven targeted therapies., Conclusion: Strategies to assess and overcome intertumor and ITH in MIBC will be critical steps toward realizing the objectives of precision oncology. Novel techniques such as analysis of circulating tumor DNA and single cell sequencing are likely to revolutionize our understanding of tumor heterogeneity., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Sequencing of cell-free DNA (cfDNA) in cancer patients' plasma offers a minimally-invasive solution to detect tumor cell genomic alterations to aid real-time clinical decision-making. The reliability of copy number detection decreases at lower cfDNA tumor fractions, limiting utility at earlier stages of the disease. To test a novel strategy for detection of allelic imbalance, we developed a prostate cancer bespoke assay, PCF&#95;SELECT, that includes an innovative sequencing panel covering ∼25 000 high minor allele frequency SNPs and tailored analytical solutions to enable allele-informed evaluation. First, we assessed it on plasma samples from 50 advanced prostate cancer patients. We then confirmed improved detection of genomic alterations in samples with <10% tumor fractions when compared against an independent assay. Finally, we applied PCF&#95;SELECT to serial plasma samples intensively collected from three patients previously characterized as harboring alterations involving DNA repair genes and consequently offered PARP inhibition. We identified more extensive pan-genome allelic imbalance than previously recognized in prostate cancer. We confirmed high sensitivity detection of BRCA2 allelic imbalance with decreasing tumor fractions resultant from treatment and identified complex ATM genomic states that may be incongruent with protein losses. Overall, we present a framework for sensitive detection of allele-specific copy number changes in cfDNA., (© The Author(s) 2022. Published by Oxford University Press on behalf of NAR Cancer.)

Purpose: Pulmonary involvement is rare in metastatic hormone-sensitive prostate cancer (mHSPC) that recurs after treatment for localized disease. Guidelines recommend intensive systemic therapy, similar to patients with liver metastases, but some lung-recurrent mHSPC may have good outcomes. Genomic features of lung metastases may clarify disease aggression, but are poorly understood since lung biopsy is rarely performed. We present a comparative assessment of genomic drivers and heterogeneity in metachronous prostate tumors and lung metastases., Methods: We leveraged a prospective functional imaging study of 208 biochemically recurrent prostate cancers to identify 10 patients with lung-recurrent mHSPC. Histologic diagnosis was attained via thoracic surgery or fine-needle lung biopsy. We retrieved clinical data and performed multiregion sampling of primary tumors and metastases. Targeted and/or whole-exome sequencing was applied to 46 primary and 32 metastatic foci., Results: Unusually for mHSPC, all patients remained alive despite a median follow-up of 11.5 years. Several patients experienced long-term freedom from systemic treatment. The genomic landscape of lung-recurrent mHSPC was typical of curable prostate cancer with frequent PTEN , SPOP , and chromosome 8p alterations, and there were no deleterious TP53 and DNA damage repair gene mutations that characterize aggressive prostate cancer. Despite a long median time to recurrence (76.8 months), copy number alterations and clonal mutations were highly conserved between metastatic and primary foci, consistent with intrapatient homogeneity and limited genomic evolution., Conclusion: In this retrospective hypothesis-generating study, we observed indolent genomic etiology in selected lung-recurrent mHSPC, cautioning against grouping these patients together with liver or bone-predominant mHSPC. Although our data do not generalize to all patients with lung metastases, the results encourage prospective efforts to stratify lung-recurrent mHSPC by genomic features., Competing Interests: Nicolaas LumenResearch Funding: Bayer (Inst), Janssen (Inst)Travel, Accommodations, Expenses: Ipsen (Inst) Matti AnnalaLeadership: Fluivia OyStock and Other Ownership Interests: Fluivia Oy Alexander W. WyattThis author is a member of the JCO Precision Oncology Editorial Board. Journal policy recused the author from having any role in the peer review of this manuscript.Honoraria: Janssen, Astellas Pharma, AstraZeneca, Merck, AstraZeneca CanadaConsulting or Advisory Role: AstraZenecaResearch Funding: ESSA (Inst) Piet OstConsulting or Advisory Role: Janssen-Cilag, Bayer, Astellas Pharma, Curium Pharma, Telix Pharmaceuticals, NovartisResearch Funding: Varian Medical Systems (Inst), Bayer (Inst)Travel, Accommodations, Expenses: FerringNo other potential conflicts of interest were reported.

Context: Multiple studies have reported on the genomic characteristics of metastatic hormone-sensitive prostate cancer (mHSPC). The impact of these findings on prognostication, treatment selection, and clinical trial design remains unclear., Objective: To summarise genomic alteration prevalences in liquid and/or tissue biopsies, infer their clinical implications, and compare genomic alteration frequencies across different disease states and clinical phenotypes., Evidence Acquisition: The PubMed and Web of Knowledge databases were systematically searched up to January 2021. Quality assessment was performed using the Joanna Briggs Institute Critical Appraisal tools., Evidence Synthesis: In total, 11 studies encompassing 1682 mHSPC patients were included. High-volume disease was associated with more frequent alterations in TP53, DNA damage repair, and Wnt pathways. Tumours from patients with de novo mHSPC were enriched for alterations in TP53 and CDK12 compared with recurrent disease. Alterations in AR, TP53, cell cycle signalling, and MYC were associated with a poorer clinical outcome. A comparative analysis of gene alteration frequencies across disease states revealed a relative increase from localised to castration-resistant tumours, with noteworthy enrichment of CTNNB1 alterations in mHSPC (5%), which warrants further investigation. This study was limited by variability in methodology and definitions used among the eligible studies, including differences in sequencing methods, analytes (being either tissue or liquid), alteration calling thresholds, and target patient populations with a relative under-representation of recurrent metastatic disease., Conclusions: Several genomic alterations are associated with differential prognosis and clinical phenotypes in mHSPC. We urge that emerging data on these potential predictive biomarkers must be validated in biomarker-driven randomised controlled trials before any clinical implementation. Alignment of the assay methodology and reporting will be critical for ensuring rapid scalability., Patient Summary: We reviewed current data on genomic alterations of metastatic hormone-sensitive prostate cancer, and summarised key genomic subtypes that associate with specific clinical phenotypes and treatment outcomes., (Copyright © 2021 European Association of Urology. Published by Elsevier B.V. All rights reserved.)

Prostate cancer is a significant cause of cancer mortality. It has been well-established that certain germline pathogenic variants confer both an increased risk of being diagnosed with prostate cancer and dying of prostate cancer.1 There are exciting developments in both the availability of genetic testing and opportunities for improved treatment of patients.On August 19, 2020, the Princess Margaret Cancer Centre in Toronto, Ontario, hosted a virtual retreat, bringing together international experts in urology, medical oncology, radiation oncology, medical genetics, and translational research, as well as a patient representative. We are pleased to provide this manuscript as a review of those proceedings for Canadian clinicians.We highlighted several needs for future research and policy action based on this meeting:Increased access to funding for germline testing for the common genetic disorders associated with increased risk of prostate cancer.More research into identifying genetic factors influencing risk stratification, treatment response, and outcomes of prostate cancer within Canadian populations at higher genetic risk for prostate cancer.Added awareness about genetic risk factors among the Canadian public.Development of patient-specific and reported outcomes research in tailored care for patients at increased genetic risk of prostate cancer.Creation of multidisciplinary clinics that specialize in tailored care for patients at increased genetic risk of prostate cancer.

Circulating tumor DNA (ctDNA) enables real-time genomic profiling of cancer without the need for tissue biopsy. ctDNA-based technology is seeing rapid uptake in clinical practice due to the potential to inform patient management from diagnosis to advanced disease. In metastatic disease, ctDNA can identify somatic mutations, copy-number variants (CNVs), and structural rearrangements that are predictive of therapy response. However, the ctDNA fraction (ctDNA%) is unpredictable and confounds variant detection strategies, undermining confidence in liquid biopsy results. Assay design also influences which types of genomic alterations are identifiable. Here, we describe the relationships between ctDNA%, methodology, and sensitivity-specificity for major classes of genomic alterations in prostate cancer. We provide recommendations to navigate the technical complexities that constrain the detection of clinically relevant genomic alterations in ctDNA., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Purpose: Nearly all men with prostate cancer treated with androgen receptor (AR) signaling inhibitors (ARSIs) develop resistance via diverse mechanisms including constitutive activation of the AR pathway, driven by AR genomic structural alterations, expression of AR splice variants (AR-Vs), or loss of AR dependence and lineage plasticity termed neuroendocrine prostate cancer. Understanding these de novo acquired ARSI resistance mechanisms is critical for optimizing therapy., Materials and Methods: A novel liquid biopsy technology was used to collect mRNA from circulating tumor cells (CTCs) to measure expression of AR-Vs, AR targets, and neuroendocrine prostate cancer markers. An institutional review board-approved prospective cohort (N = 99) was used to identify patterns of gene expression. Two prospective multicenter phase II clinical trials of ARSIs for men with castration-resistant prostate cancer (ClinicalTrials.gov: NCT01942837 [enzalutamide, N = 21] and NCT02025010 [abiraterone, N = 27]) were used to further validate these findings., Results: Hierarchical clustering of CTC transcripts identified two distinct clusters. Cluster 2 (C2) exhibited increased expression of AR-regulated genes and was associated with worse overall survival (median 8.6 v 22.4 months; P < .01; hazard ratio [HR] = 3.45 [1.9 to 6.14]). In multivariable analysis, C2 was prognostic independent of other clinicopathologic variables. AR-V status was not significant when accounting for C2. Upon further validation in pooled multicenter phase II trials, C2 was associated with worse overall survival (15.2 months v not reached; P < .01; HR = 8.43 [2.74 to 25.92]), prostate-specific antigen progression-free survival (3.6 v 12 months; P < .01; HR = 4.64 [1.53 to 14.11]), and radiographic progression-free survival (2.7 v 40.6 months; P < .01; HR = 4.64 [1.82 to 17.41])., Conclusion: We demonstrate that a transcriptional profile detectable in CTCs obtained from liquid biopsies can serve as an independent prognostic marker beyond AR-V7 in patients with metastatic prostate cancer and can be used to identify the emergence of multiple ARSI resistance mechanisms. This is currently being investigated in additional prospective trials., Competing Interests: Hamid EmamekhooConsulting or Advisory Role: Exelixis, Bayer, Bristol Myers Squibb, Cardinal Health, Seattle GeneticsResearch Funding: Bristol Myers Squibb, Exelixis, Replimune, Merck, Calithera Biosciences, Roche/GenentechTravel, Accommodations, Expenses: DAVA Pharmaceuticals Rana R. McKayConsulting or Advisory Role: Janssen, Novartis, Tempus, Exelixis, Pfizer, Bristol Myers Squibb, Astellas Medivation, Dendreon, Bayer, Sanofi, Merck, Vividion Therapeutics, Calithera Biosciences, AstraZenecaResearch Funding: Pfizer, Bayer, Tempus Xiao X. WeiHonoraria: OncLiveConsulting or Advisory Role: NovartisResearch Funding: Bristol Myers SquibbTravel, Accommodations, Expenses: Corvus Pharmaceuticals Rebecca SilverResearch Funding: Bayer Michael J. MorrisConsulting or Advisory Role: Bayer, Endocyte, Advanced Accelerator Applications, ORIC Pharmaceuticals, Johnson & Johnson, Curium Pharma, AthenexResearch Funding: Bayer, Sanofi, Endocyte, Progenics, Corcept Therapeutics, Roche/Genentech, JanssenTravel, Accommodations, Expenses: Endocyte, Fujifilm Felix Y. FengConsulting or Advisory Role: Astellas, Bayer, BlueEarth Diagnostics, Celgene, EMD Serono, Genentech, Janssen, Myovant, Ryovant, Bristol Myers Squibb, Exact Sciences, Varian, Bluestar Genomics, SerimmunResearch Funding: Zenith Epigenetics Howard I. ScherConsulting or Advisory Role: Janssen, Amgen, Janssen Research & Development, Menarini Silicon Biosystems, WIRB-Copernicus Group, ESSA, Ambry Genetics/Konica Minolta, Pfizer, Bayer, Sun PharmaResearch Funding: Janssen, Illumina, Epic Sciences, Menarini Silicon Biosystems, Thermofisher Scientific BiomarkersPatents, Royalties, Other Intellectual Property: BioNTech—Intellectual Property Rights, Elucida Oncology—Intellectual Property Rights, MabVAX—Intellectual Property Rights, Y-mAbs Therapeutics Inc—Intellectual Property RightsTravel, Accommodations, Expenses: Asterias Biotherapeutics, Menarini Silicon Biosystems, Amgen, WIRB-Copernicus Group, Konica Minolta, ESSA, Prostate Cancer Foundation, Sanofi, Bayer, Phosplatin Therapeutics Dana RathkopfConsulting or Advisory Role: Janssen, Genentech, AstraZeneca, Bayer, Myovant SciencesResearch Funding: Janssen Oncology, Medivation, Celgene, Takeda, Millennium, Ferring, Novartis, Taiho Pharmaceutical, AstraZeneca, Genentech/Roche, TRACON Pharma, Bayer, Phosplatin Therapeutics Scott M. DehmConsulting or Advisory Role: Celgene, Oncternal Therapeutics, Janssen Research & DevelopmentResearch Funding: Janssen Research & Development, Medivation/AstellasPatents, Royalties, Other Intellectual Property: Royalties from licensing genome-engineered prostate cancer cell lines Toni K. ChoueiriEmployment: Dana Farber Cancer HospitalLeadership: Dana Farber Cancer Hospital, NCCN, KidneyCAN, ASCOStock and Other Ownership Interests: Pionyr, Tempest TherapeuticsHonoraria: NCCN, UpToDate, Michael J. Hennessy Associates, ASCO, Harborside Press, Analysis Group, AstraZeneca, Alexion Pharmaceuticals, Sanofi/Aventis, Bayer, Bristol Myers Squibb, Genentech/Roche, GlaxoSmithKline, Merck, Novartis, Peloton Therapeutics, Pfizer, Corvus Pharmaceuticals, Ipsen, Foundation Medicine, Eisai, PlatformQ Health, Clinical Care Options, Navinata Health, Kidney Cancer Association, Exelixis, Prometheus, Lpath, The New England Journal of Medicine, Lancet Oncology, Cerulean Pharma, Alligent, EMD Serono, HERON, Lilly, Janssen Oncology, IQvia, Aveo, NCI GU Steering CommitteeConsulting or Advisory Role: Pfizer, Bayer, Novartis, GlaxoSmithKline, Merck, Bristol Myers Squibb, Roche/Genentech, Eisai, Foundation Medicine, Cerulean Pharma, AstraZeneca, Exelixis, Prometheus, Alligent, Ipsen, Corvus Pharmaceuticals, Lpath, Alexion Pharmaceuticals, Sanofi/Aventis, Peloton Therapeutics, UpToDate, NCCN, Michael J. Hennessy Associates, Analysis Group, Kidney Cancer Association, Clinical Care Options, PlatformQ Health, Navinata Health, Harborside Press, ASCO, The New England Journal of Medicine, Lancet Oncology, EMD Serono, HERON, Lilly, ESMOResearch Funding: Pfizer, Novartis, Merck, Exelixis, TRACON Pharma, GlaxoSmithKline, Bristol Myers Squibb, AstraZeneca, Peloton Therapeutics, Roche/Genentech, Celldex, Agensys, Eisai, Takeda, Prometheus, Ipsen, Corvus Pharmaceuticals, Cerulean Pharma, Seattle Genetics/Astellas, Bayer, Foundation Medicine, Roche, Calithera Biosciences, Analysis Group, NCI, Gateway for Cancer Research, Congressionally Directed Medical Research Programs (DOD)Patents, Royalties, Other Intellectual Property: International Patent Application No. PCT/US2018/058430, titled “Biomarkers of Clinical Response and Benefit to Immune Checkpoint Inhibitor Therapy,” and International Patent Application No. PCT/US2018/12209, titled “PBRM1 Biomarkers Predictive of Anti-Immune Checkpoint Response”Travel, Accommodations, Expenses: Pfizer, Bayer, Novartis, GlaxoSmithKline, Merck, Bristol Myers Squibb, Roche/Genentech, Eisai, Foundation Medicine, Cerulean Pharma, AstraZeneca, Exelixis, Prometheus, Alligent, Ipsen, Corvus Pharmaceuticals, Lpath, Alexion Pharmaceuticals, Sanofi/Aventis, UpToDate, Peloton Therapeutics, NCCN, Michael J. Hennessy Associates, Analysis Group, Kidney Cancer Association, Clinical Care Options, PlatformQ Health, Harborside Press, Navinata Health, The New England Journal of Medicine, Lancet Oncology, EMD Serono, HERON, Lilly, ESMOOther Relationship: Medical writing and editorial assistance support might have been funded by Communications companies funded by pharmaceutical companies such as ClinicalThinking, Health Interactions, Envision Pharma Group, Fishawack Group of Companies, Parexel Susan HalabiEmployment: ASCO Andrew J. ArmstrongHonoraria: Astellas Scientific and Medical Affairs IncConsulting or Advisory Role: Bayer, Dendreon, Pfizer, Astellas Scientific and Medical Affairs Inc, Clovis Oncology, AstraZeneca, Merck, Bristol Myers SquibbResearch Funding: Dendreon, Bayer, Pfizer, Novartis, Janssen Oncology, Astellas Pharma, Gilead Sciences, Roche/Genentech, Bristol Myers Squibb, Constellation Pharmaceuticals, Merck, AstraZeneca, BeiGenePatents, Royalties, Other Intellectual Property: Circulating tumor cell novel capture technologyTravel, Accommodations, Expenses: Astellas Scientific and Medical Affairs Inc Alexander W. WyattHonoraria: Janssen, Astellas Pharma, AstraZeneca, Merck, AstraZeneca CanadaConsulting or Advisory Role: AstraZenecaResearch Funding: ESSA Mary-Ellen TaplinHonoraria: Janssen-Ortho, Clovis Oncology, Astellas Pharma, Incyte, UpToDate, Research to Practice, Pfizer, Bayer, Amgen, AstraZeneca, Progenics, Guidepoint Global, Celgene, Merck, GlaxoSmithKline, Myovant Sciences, Roivant, AbbVie, Arcus Biosciences, Constellation PharmaceuticalsConsulting or Advisory Role: Janssen-Ortho, Bayer, Guidepoint Global, Best Doctors Inc, UpToDate, Clovis Oncology, Research to Practice, Myovant Sciences, Incyte, Pfizer, AstraZeneca, Arcus VenturesResearch Funding: Janssen-Ortho, Medivation, Bayer, PfizerTravel, Accommodations, Expenses: Medivation, Janssen Oncology, Tokai Pharmaceuticals, Astellas Pharma, Incyte, Pfizer, Clovis Oncology, Bayer Shuang G. ZhaoEmployment: Exact Sciences (I)Patents, Royalties, Other Intellectual Property: Patent applications pending with Decipher Biosciences, Exact Sciences Joshua M. LangStock and Other Ownership Interests: Salus DiscoveryConsulting or Advisory Role: Sanofi, Immunomedics, Janssen, Pfizer/Astellas, 4D PharmaResearch Funding: Medivation, Agensys, GlaxoSmithKline, Immunomedics, Bristol Myers Squibb, JanssenPatents, Royalties, Other Intellectual Property: I am listed on the patent on a technology for rare cell capture and analysis. This technology has been licensed by Salus Discovery LLC although no commercial products are availableNo other potential conflicts of interest were reported.

Purpose: In the placebo-controlled SPARTAN study, apalutamide added to androgen-deprivation therapy (ADT) improved metastasis-free survival, second progression-free survival (PFS2), and overall survival (OS) in patients with nonmetastatic castration-resistant prostate cancer (nmCRPC). Mechanisms of resistance to apalutamide in nmCRPC require evaluation., Patients and Methods: In a subset of patients from SPARTAN, aberrations were assessed at baseline and end of study treatment (EOST) using targeted next-generation sequencing or qRT-PCR. Circulating-tumor DNA (ctDNA) levels were assessed qualitatively. Select aberrations in androgen receptor (AR) and other common PC-driving genes were detected and summarized by the treatment group; genomic aberrations were summarized in ctDNA-positive samples. Association between detection of aberrations in all patients and outcomes was assessed using Cox proportional-hazards models and multivariate analysis., Results: In 247 patients, the overall prevalence of ctDNA, AR aberrations, and TP53 inactivation increased from baseline (40.6%, 13.6%, and 22.2%) to EOST (57.1%, 25.4%, and 35.0%) and was comparable between treatment groups at EOST. In patients who received subsequent androgen signaling inhibition after study treatment, detectable biomarkers at EOST were significantly associated with poor outcomes: ctDNA with PFS2 or OS (HR, 2.01 or 2.17, respectively; P < 0.0001 for both), any AR aberration with PFS2 (1.74; P = 0.024), and TP53 or BRCA2 inactivation with OS (2.06; P = 0.003; or 3.1; P < 0.0001)., Conclusions: Apalutamide plus ADT did not increase detectable AR/non-AR aberrations over ADT alone. Detectable ctDNA, AR aberrations, and TP53/BRCA2 inactivation at EOST were associated with poor outcomes in patients treated with first subsequent androgen signaling inhibitor., (©2021 American Association for Cancer Research.)

Purpose: Cross-resistance renders multiple lines of androgen receptor (AR) signaling inhibitors increasingly futile in metastatic castration-resistant prostate cancer (mCRPC). We sought to determine acquired genomic contributors to cross-resistance., Experimental Design: We collected 458 serial plasma cell-free DNA samples at baseline and progression timepoints from 202 patients with mCRPC receiving sequential AR signaling inhibitors (abiraterone and enzalutamide) in a randomized phase II clinical trial (NCT02125357). We utilized deep targeted and whole-exome sequencing to compare baseline and posttreatment somatic genomic profiles in circulating tumor DNA (ctDNA)., Results: Patient ctDNA abundance was correlated across plasma collections and independently prognostic for sequential therapy response and overall survival. Most driver alterations in established prostate cancer genes were consistently detected in ctDNA over time. However, shifts in somatic populations after treatment were identified in 53% of patients, particularly after strong treatment responses. Treatment-associated changes converged upon the AR gene, with an average 50% increase in AR copy number, changes in AR mutation frequencies, and a 2.5-fold increase in the proportion of patients carrying AR ligand binding domain truncating rearrangements., Conclusions: Our data show that the dominant AR genotype continues to evolve during sequential lines of AR inhibition and drives acquired resistance in patients with mCRPC., (©2021 American Association for Cancer Research.)

Background: Treatment of poor prognosis metastatic castration-resistant prostate cancer (mCRPC) includes taxane chemotherapy and androgen receptor pathway inhibitors (ARPI). We sought to determine optimal treatment in this setting., Patients and Methods: This multicentre, randomised, open-label, phase II trial recruited patients with ARPI-naive mCRPC and poor prognosis features (presence of liver metastases, progression to mCRPC after <12 months of androgen deprivation therapy, or ≥4 of 6 clinical criteria). Patients were randomly assigned 1 : 1 to receive cabazitaxel plus prednisone (group A) or physician's choice of enzalutamide or abiraterone plus prednisone (group B) at standard doses. Patients could cross over at progression. The primary endpoint was clinical benefit rate for first-line treatment (defined as prostate-specific antigen response ≥50%, radiographic response, or stable disease ≥12 weeks)., Results: Ninety-five patients were accrued (median follow-up 21.9 months). First-line clinical benefit rate was greater in group A versus group B (80% versus 62%, P = 0.039). Overall survival was not different between groups A and B (median 37.0 versus 15.5 months, hazard ratio (HR) = 0.58, P = 0.073) nor was time to progression (median 5.3 versus 2.8 months, HR = 0.87, P = 0.52). The most common first-line treatment-related grade ≥3 adverse events were neutropenia (cabazitaxel 32% versus ARPI 0%), diarrhoea (9% versus 0%), infection (9% versus 0%), and fatigue (7% versus 5%). Baseline circulating tumour DNA (ctDNA) fraction above the cohort median and on-treatment ctDNA increase were associated with shorter time to progression (HR = 2.38, P < 0.001; HR = 4.03, P < 0.001). Patients with >30% ctDNA fraction at baseline had markedly shorter overall survival than those with undetectable ctDNA (HR = 38.22, P < 0.001)., Conclusions: Cabazitaxel was associated with a higher clinical benefit rate in patients with ARPI-naive poor prognosis mCRPC. ctDNA abundance was prognostic independent of clinical features, and holds promise as a stratification biomarker., Competing Interests: Disclosures KNC reports honoraria and/or consulting fees from Astellas, AstraZeneca, Constellation Pharmaceuticals, Daiichi Sankyo, Janssen, Merck, Novartis, Pfizer, Point Biopharma, Roche, Sanofi, and grants and research funding from Astellas, AstraZeneca, Janssen, Merck, Novartis, Pfizer, Roche, Sanofi. AWW reports a commercial research grant from Janssen and honoraria from AstraZeneca, Astellas, Janssen, and Merck. AAA reports honoraria, consulting fees, and/or research funding from Astellas, AstraZeneca, Janssen, Novartis, Sanofi, Tolmar, Telix, Merck Serono, Bristol Myers Squibb (BMS), Ipsen, Bayer, Pfizer, Amgen, Noxopharm, Aptevo Therapeutics, Glaxo Smith Kline, MedImmune, SYNthorx, Bionomics, Merck Sharpe Dome, and Sanofi Aventis. LAW reports serving on advisory boards (with no personal financial contribution) for Pfizer, EISAI, AstraZeneca, Merck, BMS, and Ipsen, and grants from Pfizer, Merck, AstraZeneca, Roche, and BMS. BT reports grants and personal fees from Amgen, AstraZeneca, BMS, Janssen, Pfizer, MDS, Ipsen and Bayer, grants from Astellas, and personal fees from Sanofi, Tolmar, Novartis, IQVIA, and Roche. All other authors have declared no conflicts of interest., (Copyright © 2021 European Society for Medical Oncology. Published by Elsevier Ltd. All rights reserved.)

Analysis of the genomic landscape of prostate cancer has identified different molecular subgroups with relevance for novel or existing targeted therapies. The recent approvals of the poly(ADP-ribose) polymerase (PARP) inhibitors olaparib and rucaparib in the metastatic castration-resistant prostate cancer (mCRPC) setting signal the need to embed molecular diagnostics in the clinical pathway of patients with mCRPC to identify those who can benefit from targeted therapies. Best practice guidelines in overall biospecimen collection and processing for molecular analysis are widely available for several tumour types. However, there is no standard protocol for molecular diagnostic testing in prostate cancer. Here, we provide a series of recommendations on specimen handling, sample pre-analytics, laboratory workflow, and testing pathways to maximise the success rates for clinical genomic analysis in prostate cancer. Early involvement of a multidisciplinary team of pathologists, urologists, oncologists, radiologists, nurses, molecular scientists, and laboratory staff is key to enable optimal workflow for specimen selection and preservation at the time of diagnosis so that samples are available for molecular analysis when required. Given the improved outcome of patients with mCRPC and homologous recombination repair gene alterations who have been treated with PARP inhibitors, there is an urgent need to incorporate high-quality genomic testing in the routine clinical pathway of these patients., (© 2021 The Authors. The Journal of Pathology: Clinical Research published by The Pathological Society of Great Britain and Ireland & John Wiley & Sons, Ltd.)