Genomic Characterization of Prostatic Ductal Adenocarcinoma Identifies a High Prevalence of DNA Repair Gene Mutations

Molecular Pathology of Prostate Cancer

Molecular profiling studies have shed new light on the complex biology of prostate cancer. Genomic studies have highlighted that structural rearrangements are among the most common recurrent alterations. In addition, both germline and somatic mutations in DNA repair genes are enriched in patients with advanced disease. Primary prostate cancer has long been known to be multifocal, but recent studies demonstrate that a large fraction of prostate cancer shows evidence of multiclonality, suggesting that genetically distinct, independently arising tumor clones coexist. Metastatic prostate cancer shows a high level of morphologic and molecular diversity, which is associated with resistance to systemic therapies. The resulting high level of intratumoral heterogeneity has important implications for diagnosis and poses major challenges for the implementation of molecular studies. Here we provide a concise review of the molecular pathology of prostate cancer, highlight clinically relevant alterations, and discuss opportunities for molecular testing.

Role of N6‑methyladenosine in the pathogenesis, diagnosis and treatment of prostate cancer (Review)

Prostate cancer (PCa) affects males of all racial and ethnic groups, and leads to higher rates of mortality in those belonging to a lower socioeconomic status due to the late detection of the disease. PCa affects middle‑aged males between the ages of 45 and 60 years, and is the highest cause of cancer‑associated mortality in Western countries. As the most abundant and common mRNA modification in higher eukaryotes, N6‑methyladenosine (m6A) is widely distributed in mammalian cells and influences various aspects of mRNA metabolism. Recent studies have found that abnormal expression levels of various m6A regulators significantly affect the development and progression of various types of cancer, including PCa. The present review discusses the influence of m6A regulatory factors on the pathogenesis and progression of PCa through mRNA modification based on the current state of research on m6A methylation modification in PCa. It is considered that the treatment of PCa with micro‑molecular drugs that target the epigenetics of the m6A regulator to correct abnormal m6A modifications is a direction for future research into current diagnostic and therapeutic approaches for PCa.

Ductal Adenocarcinoma of the Prostate with Novel Genetic Alterations Characterized by Next-Generation Sequencing

Ductal adenocarcinoma of the prostate (DAP) is an uncommon variant of prostate cancer associated with aggressive disease and poor outcome. It presents most frequently as a mixed tumor combined with acinar adenocarcinoma. Although the histopathological features of DAP are well known, its genomic characteristics are still evolving, prompting the suggestion that all DAP would benefit from molecular analysis with the purpose of improving tumor recognition, genetic classification, and, ultimately, personalized therapy. Herein, we report a case of DAP with novel genetic alterations (BCOR P1153S, ERG M219I, KDR A750E, POLE S1896P, and RAD21 T461del).

Molecular Mechanisms of Prostate Cancer Development in the Precision Medicine Era: A Comprehensive Review

The progression of prostate cancer (PCa) relies on the activation of the androgen receptor (AR) by androgens. Despite efforts to block this pathway through androgen deprivation therapy, resistance can occur through several mechanisms, including the abnormal activation of AR, resulting in castration-resistant PCa following the introduction of treatment. Mutations, amplifications, and splicing variants in AR-related genes have garnered attention in this regard. Furthermore, recent large-scale next-generation sequencing analysis has revealed the critical roles of AR and AR-related genes, as well as the DNA repair, PI3K, and cell cycle pathways, in the onset and progression of PCa. Moreover, research on epigenomics and microRNA has increasingly become popular; however, it has not translated into the development of effective therapeutic strategies. Additionally, treatments targeting homologous recombination repair mutations and the PI3K/Akt pathway have been developed and are increasingly accessible, and multiple clinical trials have investigated the efficacy of immune checkpoint inhibitors. In this comprehensive review, we outline the status of PCa research in genomics and briefly explore potential future developments in the field of epigenetic modifications and microRNAs.

How to Integrate Prostate Cancer Biomarkers in Urology Clinical Practice: An Update

Nowadays, the management of prostate cancer has become more and more challenging due to the increasing number of available treatment options, therapeutic agents, and our understanding of its carcinogenesis and disease progression. Moreover, currently available risk stratification systems used to facilitate clinical decision-making have limitations, particularly in providing a personalized and patient-centered management strategy. Although prognosis and prostate cancer-specific survival have improved in recent years, the heterogenous behavior of the disease among patients included in the same risk prognostic group negatively impacts not only our clinical decision-making but also oncological outcomes, irrespective of the treatment strategy. Several biomarkers, along with available tests, have been developed to help clinicians in difficult decision-making scenarios and guide management strategies. In this review article, we focus on the scientific evidence that supports the clinical use of several biomarkers considered by professional urological societies (and included in uro-oncological guidelines) in the diagnosis process and specific difficult management strategies for clinically localized or advanced prostate cancer.

Clinicopathological and molecular analysis of microsatellite instability in prostate cancer: a multi-institutional study in China

Background

Microsatellite instability (MSI), or mismatch repair-deficiency (dMMR), is rare in prostate cancers (PCas). The histological and molecular features of PCas with MSI/dMMR are incompletely described. Thus, we sought to identify the characteristics of PCas with MSI/dMMR.

Methods and results

We analyzed 1,141 primary treatment-naive PCas by MMR-related protein immunohistochemistry (MLH1, PMS2, MSH2, and MSH6). We identified eight cases exhibiting MSI/dMMR (0.7%, 8/1141). Of these, six tumors had both MSH2 and MSH6 protein loss, one had both MLH1 and PMS2 protein loss, and one had only MSH6 loss. Histologically, MSI/dMMR-PCas frequently demonstrated high histological grade (Grade Group 4 or 5), ductal/intraductal histology (6/8 cases), pleomorphic giant-cell features (4/8 cases), and conspicuous tumor lymphocytic infiltration (8/8 cases). Polymerase chain reaction-based analysis of seven MSI/dMMR tumors revealed two MSI-H tumors with loss of both MSH2 and MSH6 proteins. Subsequently, the seven cases underwent next-generation sequencing (NGS) analysis with a highly validated targeted panel; four were MSI. All cases had a high tumor mutation burden (median: 45.3 mutations/Mb). Overall, the MSI/dMMR-PCas showed a high frequency of DNA damage-repair pathway gene changes, including five with pathogenic somatic or germline MMR gene mutations. Activating mutations in the MAPK pathway, PI3K pathway, and WNT/β-catenin pathway were common. TMPRSS2::ERG rearrangement was identified in one case (1/7, 14.3%).

Conclusions

Several pathological features are associated with MSI/dMMR in PCas. Identification of these features may help to select patients for genetic screening. As MSI/dMMR-PCas are enriched for actionable mutations, patients should be offered NGS to guide standard-of-care treatment.

Mutational spectrum of DNA damage and mismatch repair genes in prostate cancer

Over the past few years, a number of studies have revealed that a significant number of men with prostate cancer had genetic defects in the DNA damage repair gene response and mismatch repair genes. Certain of these modifications, notably gene alterations known as homologous recombination (HRR) genes; PALB2, CHEK2 BRCA1, BRCA2, ATM, and genes for DNA mismatch repair (MMR); MLH1, MSH2, MSH6, and PMS2 are connected to a higher risk of prostate cancer and more severe types of the disease. The DNA damage repair (DDR) is essential for constructing and diversifying the antigen receptor genes required for T and B cell development. But this DDR imbalance results in stress on DNA replication and transcription, accumulation of mutations, and even cell death, which compromises tissue homeostasis. Due to these impacts of DDR anomalies, tumor immunity may be impacted, which may encourage the growth of tumors, the release of inflammatory cytokines, and aberrant immune reactions. In a similar vein, people who have altered MMR gene may benefit greatly from immunotherapy. Therefore, for these treatments, mutational genetic testing is indicated. Mismatch repair gene (MMR) defects are also more prevalent than previously thought, especially in patients with metastatic disease, high Gleason scores, and diverse histologies. This review summarizes the current information on the mutation spectrum and clinical significance of DDR mechanisms, such as HRR and MMR abnormalities in prostate cancer, and explains how patient management is evolving as a result of this understanding.

Comparison of Survival Outcomes and Risk Factors Between Ductal Carcinoma of the Prostate and Acinar Adenocarcinoma of the Prostate: A Population-based Propensity Score-matching Study

Background

Ductal carcinoma of the prostate (DCP) is a rare type of prostate cancer (PCa) with a higher degree of infiltration and worse prognosis than acinar adenocarcinoma of the prostate (ACP). Previous reports comparing DCP and ACP have not been very reliable and involved small sample sizes.

Objective

To assess differences in mortality between ACP and DCP in a large-scale study.

Design setting and participants

Data were downloaded from the Surveillance, Epidemiology, and End Results database in June 2022. Data for 823 939 patients diagnosed with PCa from 2004 to 2019 were examined, excluding cases with survival data missing or pathological types other than DCP and ACP.

Outcome measurements and statistical analysis

Prognostic and risk factors for DCP were analyzed by generating a propensity score-matched cohort of DCP and ACP cases (1:5). Adjusted Cox models were constructed to determine hazard ratios (HRs) with 95% confidence intervals (CIs) for cancer-specific mortality (CSM) and overall mortality (OM).

Results and limitations

A total of 822 607 cases (99.8%) has ACP and 1332 (0.2%) had DCP. In comparison to ACP, age at diagnosis was significantly lower for DCP (≤66 yr: 38.0% vs 50.7%; p < 0.001) and a higher proportion of DCP patients distant metastases (13.7% vs 5.1%; p < 0.001). In comparison to the ACP group, significantly higher proportions of the DCP group underwent surgery (66.1% vs 38.1%; p < 0.001), radiotherapy (13.7% vs 3.1%; p < 0.001), or systemic therapy (18.2% vs 3.3%; p < 0.001). However, the median overall survival time was significantly shorter for DCP patients (44.0 vs 73.0 mo; p < 0.001). DCP patients also had higher risk of CSM (HR 2.07, 95% CI 1.68-2.56; p < 0.001) and OM (HR 2.73 95% CI 2.42-3.08; p < 0.001) after propensity score matching to adjust for the influence of baseline variables. Subgroup analysis showed that DCP patients who had surgical treatment had better CSM than those without surgery, while DCP patients with regional and lower stage had better OM than those with distant stage (both p < 0.05 for interaction).

Conclusions

The risk of CSM and OM is significantly higher for DCP than for ACP. Earlier detection (lower stage) and surgical treatment are beneficial factors for DCP prognosis.

Patient summary

We studied survival rates for two different types of prostate cancer. We found that survival is worse for the rarer ductal carcinoma of the prostate (DCP) than for the more common acinar adenocarcinoma of the prostate. Both early diagnosis when the cancer is at a lower stage and surgical treatment are beneficial for survival in patients with DCP.

Characteristics of BRCA2 Mutated Prostate Cancer at Presentation

Genetic alterations of DNA repair genes, particularly BRCA2 in patients with prostate cancer, are associated with aggressive behavior of the disease. It has reached consensus that somatic and germline tests are necessary when treating advanced prostate cancer patients. Yet, it is unclear whether the mutations are associated with any presenting clinical features. We assessed the incidences and characteristics of BRCA2 mutated cancers by targeted sequencing in 126 sets of advanced prostate cancer tissue sequencing data. At the time of diagnosis, cT3/4, N1 and M1 stages were 107 (85%), 54 (43%) and 35 (28%) samples, respectively. BRCA2 alterations of clinical significance by AMP/ASCO/CAP criteria were found in 19 of 126 samples (15.1%). The BRCA2 mutated cancer did not differ in the distributions of TNM stage, Gleason grade group or histological subtype compared to BRCA2 wild-type cancers. Yet, they had higher tumor mutation burden, and higher frequency of ATM and BRCA1 mutations (44% vs. 10%, p = 0.002 and 21% vs. 4%, p = 0.018, respectively). Of the metastatic subgroup (M1, n = 34), mean PSA was significantly lower in BRCA2 mutated cancers than wild-type (p = 0.018). In the non-metastatic subgroup (M0, n = 64), PSA was not significantly different (p = 0.425). A similar trend was noted in multiple metastatic prostate cancer public datasets. We conclude that BRCA2 mutated metastatic prostate cancers may present in an advanced stage with relatively low PSA.

Prognostic Role of DNA Damage Response Genes Mutations and their Association With the Sensitivity of Olaparib in Prostate Cancer Patients

Objective

Evidence shows that gene mutation is a significant proportion of genetic factors associated with prostate cancer. The DNA damage response (DDR) is a signal cascade network that aims to maintain genomic integrity in cells. This comprehensive study was performed to determine the link between different DNA damage response gene mutations and prostate cancer.

Materials and methods

A systematic literature search was performed using PubMed, Web of Science, and Embase. Papers published up to February 1, 2022 were retrieved. The DDR gene mutations associated with prostate cancer were identified by referring to relevant research and review articles. Data of prostate cancer patients from multiple PCa cohorts were obtained from cBioPortal. The OR or HR and 95% CIs were calculated using both fixed-effects models (FEMs) and random-effects models (REMs).

Results

Seventy-four studies were included in this research, and the frequency of 13 DDR genes was examined. Through the analysis of 33 articles that focused on the risk estimates of DDR genes between normal people and PCa patients, DDR genes were found to be more common in prostate cancer patients (OR = 3.6293 95% CI [2.4992; 5.2705]). Also, patients in the mutated group had a worse OS and DFS outcome than those in the unmutated group (P < .05). Of the 13 DDR genes, the frequency of 9 DDR genes in prostate cancer was less than 1%, and despite differences in race, BRCA2 was the potential gene with the highest frequency (REM Frequency = .0400, 95% CI .0324 - .0541). The findings suggest that mutations in genes such as ATR, BLM, and MLH1 in PCa patients may increase the sensitivity of Olaparib, a PARP inhibitor.

Conclusion

These results demonstrate that mutation in any DDR pathway results in a poor prognosis for PCa patients. Furthermore, mutations in ATR, BLM, and MLH1 or the expression of POLR2L, PMS1, FANCE, and other genes significantly influence Olaparib sensitivity, which may be underlying therapeutic targets in the future.

Genetic Testing and Its Clinical Application in Prostate Cancer Management: Consensus Statements from the Hong Kong Urological Association and Hong Kong Society of Uro-Oncology

Background

In recent years, indications for genetic testing in prostate cancer (PC) have expanded from patients with a family history of prostate and/or related cancers to those with advanced castration-resistant disease, and even to early PC patients for determination of the appropriateness of active surveillance. The current consensus aims to provide guidance to urologists, oncologists and pathologists working with Asian PC patients on who and what to test for in selected populations.

Methods

A joint consensus panel from the Hong Kong Urological Association and Hong Kong Society of Uro-Oncology was convened over a series of 5 physical and virtual meetings. A background literature search on genetic testing in PC was performed in PubMed, ClinicalKey, EBSCOHost, Ovid and ProQuest, and three working subgroups were formed to review and present the relevant evidence. Meeting agendas adopted a modified Delphi approach to ensure that discussions proceed in a structured, iterative and balanced manner, which was followed by an anonymous voting on candidate statements. Of 5 available answer options, a consensus statement was accepted if ≥ 75% of the panelists chose “Accept Completely” (Option A) or “Accept with Some Reservation” (Option B).

Results

The consensus was structured into three parts: indications for testing, testing methods, and therapeutic implications. A list of 35 candidate statements were developed, of which 31 were accepted. The statements addressed questions on the application of PC genetic testing data and guidelines to Asian patients, including patient selection for germline testing, selection of gene panel and tissue sample, provision of genetic counseling, and use of novel systemic treatments in metastatic castration-resistant PC patients.

Conclusion

This consensus provides guidance to urologists, oncologists and pathologists working with Asian patients on indications for genetic testing, testing methods and technical considerations, and associated therapeutic implications.

Cribriform Patterned Lesions in the Prostate Gland with Emphasis on Differential Diagnosis and Clinical Significance

Simple Summary

A cribriform structure is defined as a continuous proliferation of cells with intermingled lumina. Various entities may have a cribriform morphology within the prostate gland, ranging from normal, to benign, to borderline and even to malignant lesions. This review summarizes the morphologic features of entities that have a cribriform morphology within the prostate gland, with an emphasis on their differential diagnosis, molecular profile and clinical significance. The basic aim is to assist the pathologist with challenging and controversial cases and inform the clinician on the clinical implications of cribriform morphology.

Abstract

Cribriform glandular formations are characterized by a continuous proliferation of cells with intermingled lumina and can constitute a major or minor part of physiologic (normal central zone glands), benign (clear cell cribriform hyperplasia and basal cell hyperplasia), premalignant (high-grade prostatic intraepithelial neoplasia), borderline (atypical intraductal cribriform proliferation) or clearly malignant (intraductal, acinar, ductal and basal cell carcinoma) lesions. Each displays a different clinical course and variability in clinical management and prognosis. The aim of this review is to summarize the current knowledge regarding the morphological features, differential diagnosis, molecular profile and clinical significance of the cribriform-patterned entities of the prostate gland. Areas of controversy regarding their management, i.e., the grading of Intaductal Carcinoma, will also be discussed. Understanding the distinct nature of each cribriform lesion leads to the correct diagnosis and ensures accuracy in clinical decision-making, prognosis prediction and personalized risk stratification of patients.

Intraductal Carcinoma of the Prostate as a Cause of Prostate Cancer Metastasis: A Molecular Portrait

Simple Summary

Most men with prostate cancer will live as long as those who do not have prostate cancer. However, some men will die early of their disease due to a particular type of prostate cancer associated with recurrence and metastasis: intraductal carcinoma of the prostate. In this review, we discuss the associations between intraductal carcinoma of the prostate and metastasis, and the contemporary knowledge about the molecular alterations of intraductal carcinoma of the prostate.

Abstract

Intraductal carcinoma of the prostate (IDC-P) is one of the most aggressive types of prostate cancer (PCa). IDC-P is identified in approximately 20% of PCa patients and is associated with recurrence, metastasis, and PCa-specific death. The main feature of this histological variant is the colonization of benign glands by PCa cells. Although IDC-P is a well-recognized independent parameter for metastasis, mechanisms by which IDC-P cells can spread and colonize other tissues are not fully known. In this review, we discuss the molecular portraits of IDC-P determined by immunohistochemistry and genomic approaches and highlight the areas in which more research is needed.

Prostate Pathology: What is New in the 2022 WHO Classification of Urinary and Male Genital Tumors?

In 2022, after a six-year interval, the International Agency for Research on Cancer (IARC) has published the 5th edition of the WHO Classification of Urinary and Male Genital Tumors, which provides a comprehensive update on tumor classification of the genitourinary system. This review article focuses on prostate carcinoma and underscores changes in the prostate chapter as well as those made across the entire series of the 5th edition of WHO Blue Books. Although no major alterations were made to this chapter, some of the most notable updates include restructure of contents and introduction of a new format; standardization of mitotic counts, genomic nomenclatures, and units of length; refined definition for the terms "variant", "subtype", and "histologic pattern"; reclassification of prostatic intraepithelial neoplasia (PIN)-like adenocarcinoma as a subtype of prostatic acinar adenocarcinoma; and recognition of treatment-related neuroendocrine prostatic carcinoma as a distinct tumor type. Evolving and unsettled issues related to grading of intraductal carcinoma of the prostate and reporting of tertiary Gleason pattern, the definition and prognostic significance of cribriform growth pattern, and molecular pathology of prostate cancer will also be covered in this review.

BRCA Mutations in Prostate Cancer: Assessment, Implications and Treatment Considerations

Prostate cancer ranks fifth in cancer-related mortality in men worldwide. DNA damage is implicated in cancer and DNA damage response (DDR) pathways are in place against this to maintain genomic stability. Impaired DDR pathways play a role in prostate carcinogenesis and germline or somatic mutations in DDR genes have been found in both primary and metastatic prostate cancer. Among these, BRCA mutations have been found to be especially clinically relevant with a role for germline or somatic testing. Prostate cancer with DDR defects may be sensitive to poly(ADP-ribose) polymerase (PARP) inhibitors which target proteins in a process called PARylation. Initially they were used to target BRCA-mutated tumor cells in a process of synthetic lethality. However, recent studies have found potential for PARP inhibitors in a variety of other genetic settings. In this review, we explore the mechanisms of DNA repair, potential for genomic analysis of prostate cancer and therapeutics of PARP inhibitors along with their safety profile.

The 2019 Genitourinary Pathology Society (GUPS) White Paper on Contemporary Grading of Prostate Cancer

CONTEXT.—

Controversies and uncertainty persist in prostate cancer grading.

OBJECTIVE.—

To update grading recommendations.

DATA SOURCES.—

Critical review of the literature along with pathology and clinician surveys.

CONCLUSIONS.—

Percent Gleason pattern 4 (%GP4) is as follows: (1) report %GP4 in needle biopsy with Grade Groups (GrGp) 2 and 3, and in needle biopsy on other parts (jars) of lower grade in cases with at least 1 part showing Gleason score (GS) 4 + 4 = 8; and (2) report %GP4: less than 5% or less than 10% and 10% increments thereafter. Tertiary grade patterns are as follows: (1) replace "tertiary grade pattern" in radical prostatectomy (RP) with "minor tertiary pattern 5 (TP5)," and only use in RP with GrGp 2 or 3 with less than 5% Gleason pattern 5; and (2) minor TP5 is noted along with the GS, with the GrGp based on the GS. Global score and magnetic resonance imaging (MRI)-targeted biopsies are as follows: (1) when multiple undesignated cores are taken from a single MRI-targeted lesion, an overall grade for that lesion is given as if all the involved cores were one long core; and (2) if providing a global score, when different scores are found in the standard and the MRI-targeted biopsy, give a single global score (factoring both the systematic standard and the MRI-targeted positive cores). Grade Groups are as follows: (1) Grade Groups (GrGp) is the terminology adopted by major world organizations; and (2) retain GS 3 + 5 = 8 in GrGp 4. Cribriform carcinoma is as follows: (1) report the presence or absence of cribriform glands in biopsy and RP with Gleason pattern 4 carcinoma. Intraductal carcinoma (IDC-P) is as follows: (1) report IDC-P in biopsy and RP; (2) use criteria based on dense cribriform glands (>50% of the gland is composed of epithelium relative to luminal spaces) and/or solid nests and/or marked pleomorphism/necrosis; (3) it is not necessary to perform basal cell immunostains on biopsy and RP to identify IDC-P if the results would not change the overall (highest) GS/GrGp part per case; (4) do not include IDC-P in determining the final GS/GrGp on biopsy and/or RP; and (5) "atypical intraductal proliferation (AIP)" is preferred for an intraductal proliferation of prostatic secretory cells which shows a greater degree of architectural complexity and/or cytological atypia than typical high-grade prostatic intraepithelial neoplasia, yet falling short of the strict diagnostic threshold for IDC-P. Molecular testing is as follows: (1) Ki67 is not ready for routine clinical use; (2) additional studies of active surveillance cohorts are needed to establish the utility of PTEN in this setting; and (3) dedicated studies of RNA-based assays in active surveillance populations are needed to substantiate the utility of these expensive tests in this setting. Artificial intelligence and novel grading schema are as follows: (1) incorporating reactive stromal grade, percent GP4, minor tertiary GP5, and cribriform/intraductal carcinoma are not ready for adoption in current practice.

First case of ductal adenocarcinoma of the prostate with MAP3K1 homozygous deletion

INTRODUCTION

Ductal adenocarcinoma of the prostate is a rare prostate cancer variant and associated with higher stage and greater risk of mortality. Optimal systemic therapy for metastatic ductal adenocarcinoma is not known.

CASE PRESENTATION

A 67-year-old man presented with ductal adenocarcinoma of the prostate accompanied by multiple lung metastases and advanced bone metastases. We performed channel transurethral resection of the prostate and confirmed the diagnosis of ductal adenocarcinoma of the prostate. DNA sequencing identified a TP53 somatic point mutation (p.Gly245Ser) as the pathogenic variant. Furthermore, a homozygous deletion was observed in mitogen-activated protein kinase kinase kinase 1. The patient received enzalutamide but deceased 5 months after presenting to our institution.

CONCLUSION

To our knowledge, this is the first report of ductal adenocarcinoma of the prostate with a mitogen-activated protein kinase kinase kinase 1 homozygous deletion. Accumulation of whole-exome sequencing data is expected to inform future advances in therapy development.

Genomic and phenotypic heterogeneity in prostate cancer

From a clinical, morphological and molecular perspective, prostate cancer is a heterogeneous disease. Primary prostate cancers are often multifocal, having topographically and morphologically distinct tumour foci. Sequencing studies have revealed that individual tumour foci can arise as clonally distinct lesions with no shared driver gene alterations. This finding demonstrates that multiple genomically and phenotypically distinct primary prostate cancers can be present in an individual patient. Lethal metastatic prostate cancer seems to arise from a single clone in the primary tumour but can exhibit subclonal heterogeneity at the genomic, epigenetic and phenotypic levels. Collectively, this complex heterogeneous constellation of molecular alterations poses obstacles for the diagnosis and treatment of prostate cancer. However, advances in our understanding of intra-tumoural heterogeneity and the development of novel technologies will allow us to navigate these challenges, refine approaches for translational research and ultimately improve patient care.

Refining Immuno-Oncology Approaches in Metastatic Prostate Cancer: Transcending Current Limitations

OPINION STATEMENT

Due to its immunosuppressive tumor microenvironment, prostate cancer has historically been difficult to treat with immuno-oncology approaches. Other than pembrolizumab, which is now regulatory-approved for all microsatellite instability (MSI)-high and tumor mutational burden (TMB)-high advanced solid tumors, sipuleucel-T is the only immunotherapeutic agent approved by the US Food and Drug Administration (FDA) for prostate cancer. However, sipuleucel-T efficacy is optimal for select patients with indolent metastatic castration-resistant prostate cancer. Although manipulation of immune regulation by blocking immune checkpoints has led to substantial benefit in many cancers, experience with single-agent CTLA-4 and PD-1 or PD-L1 antibodies has shown limited effect for the majority of patients with prostate cancer, especially when administered as monotherapy. Combination therapies are now being attempted, in addition to enrichment strategies employing patient clinicopathologic and biologic characteristics that may heighten responses to immuno-oncology treatment, such as PD-L1 expression, TMB, MSI status, and alterations in CDK12. More work is needed to overcome the immune-exclusive barriers in prostate cancer, such as relatively low TMB, increased activity of myeloid-derived suppressor cells (MDSCs) and regulatory T cells, and defects in major histocompatibility complex (MHC) class I expression and interferon (IFN)-1 signaling. A promising approach and the likely next step in immuno-oncology for prostate cancer involves forced direction to markers expressed by prostate cancer tumor cells, such as prostate-specific membrane antigen (PSMA), that bypass the typical requirements for MHC class I interaction. The future will incorporate bispecific antibodies and chimeric antigen receptor (CAR)-T cells, potentially targeted towards phenotypic markers identified by next-generation PET imaging as part of the next wave of "precision medicine" in prostate cancer. Ultimately, we believe that the immune-exclusive prostate cancer tumor microenvironment can be overcome, and that patient outcomes can be enhanced through these more refined immuno-oncology approaches.

[Molecular pathology of urogenital tumors : Recommendations from the 2019 International Society of Urological Pathology (ISUP) Consensus Conference]

Das zunehmende Verständnis molekularer Grundlagen von Tumoren sowie der Fortschritt in der Diversifizierung der onkologischen Therapien versprechen individualisierte Therapieoptionen, welche bislang jedoch nur ansatzweise in die Therapieplanung von urologischen Tumoren eingegangen sind. Daher hat die Internationale Gesellschaft für Urologische Pathologie (ISUP) im März 2019 eine Konsenskonferenz zur Erarbeitung evidenzbasierter Handlungsempfehlungen zur molekularpathologischen Diagnostik beim Urothelkarzinom, Nierenzellkarzinom, Prostatakarzinom, Peniskarzinom und testikulären Keimzelltumoren durchgeführt. Die auf dieser Konsenskonferenz erarbeiteten Empfehlungen sind kürzlich in 5 separaten Manuskripten veröffentlich worden und werden in der vorliegenden Arbeit zusammengefasst.

Im Rahmen der Konferenzvorbereitung wurde eine umfassende Umfrage zur derzeitigen Praxis molekularer Testungen bei urogenitalen Tumoren unter den Mitgliedern der ISUP durchgeführt. Auf der Konferenz wurden die Ergebnisse und die entsprechenden Hintergrundinformationen durch 5 Arbeitsgruppen präsentiert und Handlungsempfehlungen für die Diagnostik erarbeitet. Eine Übereinstimmung von 66 % der Konferenzteilnehmer wurde als Konsens definiert.

Report From the International Society of Urological Pathology (ISUP) Consultation Conference on Molecular Pathology of Urogenital Cancers. I. Molecular Biomarkers in Prostate Cancer

The combined clinical and molecular heterogeneity of prostate cancer necessitates the use of prognostic, predictive, and diagnostic biomarkers to assist the clinician with treatment selection. The pathologist plays a critical role in guiding molecular biomarker testing in prostate cancer and requires a thorough knowledge of the current testing options. In the setting of clinically localized prostate cancer, prognostic biomarkers such as Ki-67 labeling, PTEN loss or mRNA-based genomic signatures can be useful to help determine whether definitive therapy is required. In the setting of advanced disease, predictive biomarkers, such as the presence of DNA repair deficiency mediated by BRCA2 loss or mismatch repair gene defects, may suggest the utility of poly-ADP ribosylase inhibition or immune checkpoint blockade. Finally, androgen receptor-related biomarkers or diagnostic biomarkers indicating the presence of small cell neuroendocrine prostate cancer may help guide the use of androgen receptor signaling inhibitors and chemotherapy. In this review, we examine the current evidence for several prognostic, predictive and diagnostic tissue-based molecular biomarkers in prostate cancer management. For each assay, we summarize a recent survey of the International Society of Urology Pathology (ISUP) members on current testing practices and include recommendations for testing that emerged from the ISUP Working Group on Molecular Pathology of Prostate Cancer and the 2019 Consultation Conference on Molecular Pathology of Urogenital Cancers.

Impact of mutations in homologous recombination repair genes on treatment outcomes for metastatic castration resistant prostate cancer

INTRODUCTION

A significant proportion of patients with metastatic castration-resistant prostate cancer (mCRPC) harbor mutations in homologous recombination (HR) repair genes, with some of these mutations associating with increased tumor susceptibility to poly(ADP-ribose) polymerase (PARP) inhibitors and platinum-based chemotherapy. While mutations in some HR repair genes (e.g., BRCA1/2) have been associated with a more aggressive clinical course, prior studies correlating HR mutational status with treatment response to androgen receptor (AR) signaling inhibitors (ARSIs) or taxane-based chemotherapy have yielded conflicting results.

METHODS

We conducted a single-center retrospective analysis to assess clinical outcomes to conventional, regulatory-approved therapies in mCRPC patients with somatic (monoallelic and biallelic) and/or germline HR repair mutations compared to patients without alterations as determined by clinical-grade next-generation sequencing assays. The primary endpoint was PSA30/PSA50 response, defined as ≥30%/≥50% prostate-specific antigen (PSA) reduction from baseline. Secondary endpoints of PSA progression-free survival (pPFS) and clinical/radiographic progression-free survival (crPFS) were estimated using Kaplan-Meier methods.

RESULTS

A total of 90 consecutively selected patients were included in this analysis, of which 33 (37%) were identified to have HR repair gene mutations. Age, race, Gleason score, prior surgery, and receipt of prior radiation therapy were comparable between carriers and non-carriers. There was no evidence that PSA30/PSA50 differed by HR gene mutational status. Median pPFS and crPFS ranged 3-14 months across treatment modalities, but there was no evidence either differed by HR gene mutational status (all p>0.05). There was also no difference in outcomes between those with BRCA2 or PALB2 mutations (n = 17) compared to those without HR repair mutations.

CONCLUSION

HR gene mutational status was associated with comparable clinical outcomes following treatment with ARSIs or taxane-based chemotherapy. Additional prospective studies are needed to confirm these findings.

PIN-like ductal carcinoma of the prostate has frequent activating RAS/RAF mutations

AIMS

Prostatic intraepithelial neoplasia-like (PIN-like) ductal carcinoma is a rare tumour characterised by often cystically dilated glands architecturally resembling high-grade PIN, but lacking basal cells. These tumours are frequently accompanied by grade group 1 acinar cancer and behave relatively indolently. In contrast, conventional ductal adenocarcinoma of the prostate is an aggressive variant comparable to grade group 4 acinar cancer. Here, we used targeted next-generation sequencing to molecularly profile PIN-like ductal carcinoma cases at radical prostatectomy.

METHODS AND RESULTS

Five PIN-like ductal carcinoma samples at radical prostatectomy with sufficient tumour tissue available were analysed for genomic alterations by targeted next-generation sequencing using the Johns Hopkins University (JHU) solid tumour panel. DNA was captured using SureSelect for 640 genes and sequenced on the Illumina HiSeq platform. Three of five (60%) of the PIN-like ductal carcinomas showed activating mutations in the RAS/RAF pathways, which are extraordinarily rare in conventional primary prostate carcinoma (<3% of cases), including an activating hot-spot BRAF mutation (p.K601E), an activating hot-spot mutation in HRAS (p.Q61K) and an in-frame activating deletion in BRAF (p.T488_Q493delinsK). An additional two cases lacked BRAF or HRAS mutations, but harboured in-frame insertions of uncertain significance in MAP2K4 and MAP3K6. One case had sufficient acinar tumour for sequencing, and showed a similar molecular profile as the concurrent PIN-like ductal carcinoma, suggesting a clonal relationship between the two components.

CONCLUSIONS

PIN-like ductal carcinoma represents a molecularly unique tumour, enriched for potentially targetable oncogenic driver mutations in the RAS/RAF/MAPK pathway. This molecular profile contrasts with that of conventional ductal adenocarcinoma, which is typically enriched for pathogenic mutations in the mismatch repair (MMR) and homologous recombination (HR) DNA repair pathways.

Genomic and Clinicopathologic Characterization of ATM-deficient Prostate Cancer

PURPOSE

The ATM (ataxia telangiectasia mutated) gene is mutated in a subset of prostate cancers, and ATM mutation may confer specific therapeutic vulnerabilities, although ATM-deficient prostate cancers have not been well-characterized.

EXPERIMENTAL DESIGN

We genetically validated a clinical grade IHC assay to detect ATM protein loss and examined the frequency of ATM loss among tumors with pathogenic germline ATM mutations and genetically unselected primary prostate carcinomas using tissue microarrays (TMAs). Immunostaining results were correlated with targeted somatic genomic sequencing and clinical outcomes.

RESULTS

ATM protein loss was found in 13% (7/52) of primary Gleason pattern 5 cancers with available sequencing data and was 100% sensitive for biallelic ATM inactivation. In a separate cohort with pathogenic germline ATM mutations, 74% (14/19) had ATM protein loss of which 70% (7/10) of evaluable cases had genomic evidence of biallelic inactivation, compared with zero of four of cases with intact ATM expression. By TMA screening, ATM loss was identified in 3% (25/831) of evaluable primary tumors, more commonly in grade group 5 (17/181; 9%) compared with all other grades (8/650; 1%; P < 0.0001). Of those with available sequencing, 80% (4/5) with homogeneous ATM protein loss and 50% (6/12) with heterogeneous ATM protein loss had detectable pathogenic ATM alterations. In surgically treated patients, ATM loss was not significantly associated with clinical outcomes in random-effects Cox models after adjusting for clinicopathologic variables.

CONCLUSIONS

ATM loss is enriched among high-grade prostate cancers. Optimal evaluation of ATM status requires both genomic and IHC studies and will guide development of molecularly targeted therapies.

Implementation of Germline Testing for Prostate Cancer: Philadelphia Prostate Cancer Consensus Conference 2019

PURPOSE

Germline testing (GT) is a central feature of prostate cancer (PCA) treatment, management, and hereditary cancer assessment. Critical needs include optimized multigene testing strategies that incorporate evolving genetic data, consistency in GT indications and management, and alternate genetic evaluation models that address the rising demand for genetic services.

METHODS

A multidisciplinary consensus conference that included experts, stakeholders, and national organization leaders was convened in response to current practice challenges and to develop a genetic implementation framework. Evidence review informed questions using the modified Delphi model. The final framework included criteria with strong (> 75%) agreement (Recommend) or moderate (50% to 74%) agreement (Consider).

RESULTS

Large germline panels and somatic testing were recommended for metastatic PCA. Reflex testing-initial testing of priority genes followed by expanded testing-was suggested for multiple scenarios. Metastatic disease or family history suggestive of hereditary PCA was recommended for GT. Additional family history and pathologic criteria garnered moderate consensus. Priority genes to test for metastatic disease treatment included BRCA2, BRCA1, and mismatch repair genes, with broader testing, such as ATM, for clinical trial eligibility. BRCA2 was recommended for active surveillance discussions. Screening starting at age 40 years or 10 years before the youngest PCA diagnosis in a family was recommended for BRCA2 carriers, with consideration in HOXB13, BRCA1, ATM, and mismatch repair carriers. Collaborative (point-of-care) evaluation models between health care and genetic providers was endorsed to address the genetic counseling shortage. The genetic evaluation framework included optimal pretest informed consent, post-test discussion, cascade testing, and technology-based approaches.

CONCLUSION

This multidisciplinary, consensus-driven PCA genetic implementation framework provides novel guidance to clinicians and patients tailored to the precision era. Multiple research, education, and policy needs remain of importance.

A Japanese patient with ductal carcinoma of the prostate carrying an adenomatosis polyposis coli gene mutation: a case report

Background

Ductal carcinoma of the prostate is a histological subtype with a higher mortality than acinar adenocarcinoma. The number of cases is small and there are no treatment guidelines. We believe that this is the first report of ductal carcinoma of the prostate with an adenomatosis polyposis coli (APC) gene mutation in Japan.

Case presentation

An 85-year-old man presented with gross hematuria, and a papillary tumor in the prostatic urethra that was diagnosed as ductal carcinoma of the prostate following transurethral resection. Genetic analysis found an APC mutation with loss of heterozygosity. Immunostaining revealed focal nuclear translocation of β-catenin. APC mutations associated with loss of β-catenin degradation in the Wnt signaling pathway and result in over accumulation of β-catenin are thought to increase mortality. In this patient, β-catenin migrated into tumor cell nuclei.

Conclusion

To the best of our knowledge, this is the first report of ductal carcinoma of the prostate with an APC mutation in Japan. The development of a therapeutic Wnt inhibitor is discussed.

Non-metastatic ductal adenocarcinoma of the prostate: pattern of care from an uro-oncology multidisciplinary group

PURPOSE

To retrospectively review our 20 year experience of multidisciplinary management of non-metastatic ductal prostate cancer (dPC), a rare but aggressive histological subtype of prostate cancer whose optimal therapeutic approach is still controversial.

METHODS

Histologically confirmed dPC patients undergoing primary, curative treatment [radical prostatectomy (RP), external beam radiotherapy (EBRT), and androgen deprivation therapy (ADT)] were included, and percentage of ductal and acinar pattern within prostate samples were derived. Survival outcomes were assessed using the subdistribution hazard ratio (SHR) and Fine-and-Gray model.

RESULTS

From January 1997 to December 2016, 81 non-metastatic dPC fitted selection criteria. Compared to surgery alone, SHR for progression-free survival and cancer-specific mortality were 2.8 (95% CI 0.6-13.3) and 1.3 (95% CI 0.1-16.2) for exclusive EBRT, 2.7 (95% CI 0.6-13.0) and 6.5 (95% CI 0.6-69.8) for adjuvant EBRT, 4.9 (95% CI 0.7-35.5) and 5.8 (95% CI 0.5-65.6) for salvage EBRT post-prostatectomy recurrence, and 3.2 (95% CI 0.7-14.0) and 3.9 (95% CI 0.3-44.1) for primary ADT (P = 0.558; P = 0.181), respectively. Comparing multimodal treatment and monotherapy confirmed the above trends. Local recurrence more typically occurred in pure dPC patients, mixed histology more frequently produced metastatic spread (29.6% relapse in total, P = 0.026).

CONCLUSION

Albeit some limitations affected the study, our findings support the role of local treatment to achieve better disease control and improve quality of life. Different behavior, with typical local growth in pure dPC, higher distant metastatization in the mixed form, might influence treatment response. Given its poor prognosis, we recommend multidisciplinary management of dPC.

Therapeutic targeting of the DNA damage response in prostate cancer

PURPOSE OF REVIEW

The present article highlights the most common DNA repair gene mutations, using specific examples of individual genes or gene classes, and reviews the epidemiology and treatment implications for each one [with particular emphasis on poly-ADP-ribose polymerase (PARP) inhibition and PD-1 blockade].

RECENT FINDINGS

Genetic and genomic testing have an increasingly important role in the oncology clinic. For patients with prostate cancer, germline genetic testing is now recommended for all men with high-risk and metastatic disease, and somatic multigene tumor testing is recommended for men with metastatic castration-resistant disease. The most common mutations that are present in men with advanced prostate cancer are in genes coordinating DNA repair and the DNA damage response.

SUMMARY

Although much of what is discussed currently remains investigational, it is clear that genomically-targeted treatments will become increasingly important for patients with prostate cancer in the near future and beyond.

Genetic Testing in Prostate Cancer

PURPOSE OF REVIEW

This review summarizes recent advances in prostate cancer (PCa) genetics.

RECENT FINDINGS

Upwards of 20% of metastatic castration-resistant prostate tumors (mCRPC) carry homologous recombination (HR) repair gene mutations, of which ~ 10% are germline (inherited). Another ~ 5% exhibit microsatellite instability (MSI-H) and/or mismatch repair deficiency (MMRd). Pembrolizumab is approved for tumors with MMRd, thus patients with mCRPC and MMRd are candidates for pembrolizumab. Emerging data indicate that platinum chemotherapy and poly ADP-ribose polymerase inhibitors (PARPi) are effective in PCa exhibiting HR deficiency. NCCN guidelines now recommend germline and somatic tumor testing in specific clinical scenarios due to treatment and family implications. Genetic testing in PCa patients may inform prognosis, treatment options, and have implications for family counseling. PARPi, platinum chemotherapy, and immune checkpoint inhibitors are promising targeted therapies for PCa with specific molecular features. Therapeutic advances, along with importance to relatives, are driving genetic testing in prostate cancer.

"Matching" the "Mismatch" Repair-Deficient Prostate Cancer with Immunotherapy

Mismatch repair gene mutations are uncommon in advanced prostate cancer; however, in those harboring these alterations, immune checkpoint blockade can be effective. As such, assays that can accurately identify these men are critically important. Cell-free circulating tumor DNA-based sequencing approaches appear to be one viable approach for identifying these patients.See related article by Ritch et al., p. 1114.

Genomic and clinical characterization of pulmonary-only metastatic prostate cancer: A unique molecular subtype

BACKGROUND

Isolated pulmonary involvement is uncommon in metastatic hormone-sensitive prostate cancer (mHSPC). To characterize outcomes and molecular alterations of this unique patient subset, we conducted a retrospective review of patients with hormone-naïve prostate cancer presenting with lung-only metastases.

METHODS

This was a retrospective single-institution study. Medical records of 25 patients presenting with pulmonary-only metastases before receiving androgen deprivation therapy (ADT) were analyzed. Germline and/or somatic genomic results, where available (n = 16), were documented. Tumor tissue was analyzed using clinical-grade next-generation DNA sequencing assays. Clinical endpoints included complete prostate-specific antigen (PSA) response to ADT (<0.1 ng/mL), median overall survival (OS) from time of ADT initiation, median PSA progression-free survival (PSA-PFS), and failure-free survival (FFS) at 4 years.

RESULTS

Baseline characteristics were notable for 48% of men (12 of 25) having first or second-degree relatives with prostate cancer, compared with 20% expected. Complete PSA responses to ADT were noted in 52% of men, with a median PSA-PFS of 66 months, a 4-year FFS rate of 72%, and a median OS that was not reached after 190 months. In evaluable patients, molecular drivers were enriched for mismatch repair mutations (4 of 16, 25%) and homologous-recombination deficiency mutations (4 of 16, 25%). These results are limited by the small sample size and retrospective nature of this analysis.

CONCLUSIONS

This exploratory study represents one of the largest cohorts of lung-only mHSPC patients to-date. The prevalence of actionable DNA-repair gene alterations was higher than anticipated (any DNA-repair mutation: 8 of 16, 50%). Compared to historical data, these patients appear to have exceptional and durable responses to first-line ADT. This study suggests that pulmonary-tropic mHSPC biology may be fundamentally different from nonpulmonary mHSPC.

A New Molecular Taxonomy to Predict Immune Checkpoint Inhibitor Sensitivity in Prostate Cancer

Immune checkpoint agents have not yet been approved for use in advanced prostate cancer. This commentary summarizes the challenges related to this issue, in light of a recently reported case of a patient with DNA mismatch‐repair deficient castration‐resistant prostate cancer who responded to single‐agent pembrolizumab treatment.