Rucaparib in Men With Metastatic Castration-Resistant Prostate Cancer Harboring a BRCA1 or BRCA2 Gene Alteration

PROMISE: a real-world clinical-genomic database to address knowledge gaps in prostate cancer

PURPOSE

Prostate cancer is a heterogeneous disease with variable clinical outcomes. Despite numerous recent approvals of novel therapies, castration-resistant prostate cancer remains lethal. A "real-world" clinical-genomic database is urgently needed to enhance our characterization of advanced prostate cancer and further enable precision oncology.

METHODS

The Prostate Cancer Precision Medicine Multi-Institutional Collaborative Effort (PROMISE) is a consortium whose aims are to establish a repository of de-identified clinical and genomic patient data that are linked to patient outcomes. The consortium structure includes a (1) bio-informatics committee to standardize genomic data and provide quality control, (2) biostatistics committee to independently perform statistical analyses, (3) executive committee to review and select proposals of relevant questions for the consortium to address, (4) diversity/inclusion committee to address important clinical questions pertaining to racial disparities, and (5) patient advocacy committee to understand patient perspectives to improve patients' quality of care.

RESULTS

The PROMISE consortium was formed by 16 academic institutions in early 2020 and a secure RedCap database was created. The first patient record was entered into the database in April 2020 and over 1000 records have been entered as of early 2021. Data entry is proceeding as planned with the goal to have over 2500 patient records by the end of 2021.

CONCLUSIONS

The PROMISE consortium provides a powerful clinical-genomic platform to interrogate and address data gaps that have arisen with increased genomic testing in the clinical management of prostate cancer. The dataset incorporates data from patient populations that are often underrepresented in clinical trials, generates new hypotheses to direct further research, and addresses important clinical questions that are otherwise difficult to investigate in prospective studies.

Olaparib and rucaparib for the treatment of DNA repair-deficient metastatic castration-resistant prostate cancer

INTRODUCTION

Metastatic prostate cancer is a heterogeneous disease characterized by clinical and genomic heterogeneity. Many prostate cancers harbor mutations causing DNA repair deficiency, specifically homologous recombination deficiency, sensitizing to drugs that inhibit poly ADP-ribose polymerase (PARP). PARP is an enzyme that is involved in single-stranded DNA repair and is the target of newly approved treatments for metastatic prostate cancer.

AREAS COVERED

Here, the authors' review the clinical trials leading to the recent approvals of two PARP inhibitors (PARPi), olaparib and rucaparib, specifically TOPARP-A, TOPARP-B, PROfound and TRITON-2. They also compare the different FDA approvals for both of these medications and outline the safety of this class of drugs in prostate cancer.

EXPERT OPINION

Because PARPi are particularly effective in men with somatic or germline alterations in BRCA1 and BRCA2, we recommend that all men be tested for DNA alterations with next-generation sequencing in tumor cells obtained from either tissue or blood. We also recommend that olaparib or rucaparib be considered relatively early in the treatment sequence in metastatic castration-resistant prostate cancer patients with BRCA1 or BRCA2 mutations. Other DNA alterations might also sensitize to PARPi though the response rates are lower, so other standard therapies should be prioritized first.

Real-World Performance of a Comprehensive Genomic Profiling Test Optimized for Small Tumor Samples

PURPOSE

Tissue-based comprehensive genomic profiling (CGP) is increasingly used for treatment selection in patients with advanced cancer; however, tissue availability may limit widespread implementation. Here, we established real-world CGP tissue availability and assessed CGP performance on consecutively received samples.

MATERIALS AND METHODS

We conducted a post hoc, nonprespecified analysis of 32,048 consecutive tumor tissue samples received for StrataNGS, a multiplex polymerase chain reaction (PCR)-based comprehensive genomic profiling (PCR-CGP) test, as part of an ongoing observational trial (NCT03061305). Sample characteristics and PCR-CGP performance were assessed across all tested samples, including exception samples not meeting minimum input quality control (QC) requirements (< 20% tumor content [TC], < 2 mm2 tumor surface area [TSA], DNA or RNA yield < 1 ng/µL, or specimen age > 5 years). Tests reporting ≥ 1 prioritized alteration or meeting TC and sequencing QC were considered successful. For prostate carcinoma and lung adenocarcinoma, tests reporting ≥ 1 actionable or informative alteration or meeting TC and sequencing QC were considered actionable.

RESULTS

Among 31,165 (97.2%) samples where PCR-CGP was attempted, 10.7% had < 20% TC and 59.2% were small (< 25 mm2 tumor surface area). Of 31,101 samples evaluable for input requirements, 8,089 (26.0%) were exceptions not meeting requirements. However, 94.2% of the 31,101 tested samples were successfully reported, including 80.5% of exception samples. Positive predictive value of PCR-CGP for ERBB2 amplification in exceptions and/or sequencing QC-failure breast cancer samples was 96.7%. Importantly, 84.0% of tested prostate carcinomas and 87.9% of lung adenocarcinomas yielded results informing treatment selection.

CONCLUSION

Most real-world tissue samples from patients with advanced cancer desiring CGP are limited, requiring optimized CGP approaches to produce meaningful results. An optimized PCR-CGP test, coupled with an inclusive exception testing policy, delivered reportable results for > 94% of samples, potentially expanding the proportion of CGP-testable patients and impact of biomarker-guided therapies.

Barriers and facilitators of germline genetic evaluation for prostate cancer

BACKGROUND

Genetic counseling and germline testing have an increasingly important role for patients with prostate cancer (PCa); however, recent data suggests they are underutilized. Our objective was to perform a qualitative study of the barriers and facilitators of germline genetic evaluation among physicians who manage PCa.

METHODS

We conducted semi-structured interviews with medical oncologists, radiation oncologists, and urologists from different U.S. practice settings until thematic saturation was achieved at n = 14. The interview guide was based on the Tailored Implementation in Chronic Diseases Framework to identify key determinants of practice. Interview transcripts were independently coded by ≥2 investigators using a constant comparative method.

RESULTS

The decision to perform or refer for germline genetic evaluation is affected by factors at multiple levels. Although patient factors sometimes play a role, the dominant themes in the decision to conduct germline genetic evaluation were at the physician and organizational level. Physician knowledge, coordination of care, perceptions of the guidelines, and concerns about cost were most frequently discussed as the main factors affecting utilization of germline genetic evaluation.

CONCLUSIONS

There are currently numerous barriers to implementation of germline genetic evaluation for PCa. Efforts to expand physician education, to develop tools to enhance genetics in practice, and to facilitate coordination of care surrounding genetic evaluation are important to promote guideline-concordant care.

Real-World Treatment Patterns and Overall Survival of Patients with Metastatic Castration-Resistant Prostate Cancer in the US Prior to PARP Inhibitors

Introduction

Therapeutic options for metastatic castration-resistant prostate cancer (mCRPC) patients are continuously advancing. We described mCRPC treatment patterns in the US from 2013 to 2019.

Methods

Patients with a confirmed mCRPC diagnosis and adenocarcinoma histology were included in the US Flatiron Health Electronic Health Record-derived de-identified database. Treatment patterns [including treatment per lines of therapies (LOTs), LOT sequences, and time on treatment] and overall survival (OS) have been described in mCRPC settings.

Results

Of 5213 patients (mean age: 72.6 years), 4374 (83.9%) were treated with ≥ 1 LOT post-mCRPC diagnosis (among those with ≥ 1 LOT, 55.3%, 29.5%, 14.7%, and 6.7% had ≥ 2, 3, 4, and 5 LOTs, respectively). In first line (1L), the main treatment class was next-generation hormonal agents (NHA; 62.5% of patients with ≥ 1 LOT), while the shortest and longest time on 1L were observed for chemotherapy (median 2.8 months) and NHA (median 5.1 months), respectively. The most common LOT sequences were NHA → NHA (29.4% of patients with ≥ 2 LOTs) and NHA → NHA → chemotherapy (16.7% of patients with ≥ 3 LOTs). In Kaplan–Meier analyses, the median OS was 19.4, 14.6, and 11.1 months post-1L, 2L, and 3L start, respectively. Patients who moved rapidly through LOTs had an increased risk of death.

Conclusions

NHA were widely used as 1L therapy in mCRPC patients from 2013 to 2019, but time on 1L NHA treatment was on average < 6 months. While NHA → NHA was the most observed 1L → 2L LOT sequence, a plethora of other LOT sequences were observed. OS was poor, highlighting an unmet need for life-prolonging treatments.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01823-6.

On the application of 3d metals for C-H activation toward bioactive compounds: The key step for the synthesis of silver bullets

Several valuable biologically active molecules can be obtained through C-H activation processes. However, the use of expensive and not readily accessible catalysts complicates the process of pharmacological application of these compounds. A plausible way to overcome this issue is developing and using cheaper, more accessible, and equally effective catalysts. First-row transition (3d) metals have shown to be important catalysts in this matter. This review summarizes the use of 3d metal catalysts in C-H activation processes to obtain potentially (or proved) biologically active compounds.

The Future of Parallel Tumor and Germline Genetic Testing: Is There a Role for All Patients With Cancer?

Under the traditional paradigm of genetic testing in cancer, the role of germline testing was to assess for the inherited risk of cancer, whereas the role of tumor testing was to determine therapeutic selection. Parallel tumor-normal genetic testing uses simultaneous genetic testing of the tumor and normal tissue to identify mutations and allows their classification as either germline or somatic. The increasing adoption of parallel testing has revealed a greater number of germline findings in patients who otherwise would not have met clinical criteria for testing. This result has widespread implications for the screening and further testing of at-risk relatives and for gene discovery. It has also revealed the importance of germline testing in therapeutic actionability. Herein, we describe the pros and cons of tumor-only versus parallel tumor-normal testing and summarize the data on the prevalence of incidental actionable germline findings. Because germline testing in patients with cancer continues to expand, it is imperative that systems be in place for the proper interpretation, dissemination, and counseling for patients and at-risk relatives. We also review new therapeutic approvals with germline indications and highlight the increasing importance of germline testing in selecting therapies. Because recommendations for universal genetic testing are increasing in multiple cancer types and the number of approved therapies with germline indications is also increasing, a gradual transition toward parallel tumor-normal genetic testing in all patients with cancer is foreseeable.

Mutations in TP53 or DNA damage repair genes define poor prognostic subgroups in primary prostate cancer

BACKGROUND

Mutations in DNA damage repair genes, in particular genes involved in homology-directed repair, define a subgroup of men with prostate cancer with a more unfavorable prognosis but a therapeutic vulnerability to PARP inhibition. In current practice, mutational testing of prostate cancer patients is commonly done late i.e., when the tumor is castration resistant. In addition, most sequencing panels do not include TP53, one of the most crucial tumor suppressor genes in human cancer. In this proof-of-concept study, we sought to extend the clinical use of these molecular markers by exploring the early prognostic impact of mutations in TP53 and DNA damage repair genes in men with primary, nonmetastatic prostate cancer undergoing radical prostatectomy (RPX).

METHODS

Tumor specimens from a cohort of 68 RPX patients with intermediate (n = 11, 16.2%) or high-risk (n = 57, 83.8%) disease were analyzed by targeted next generation sequencing using a 37 DNA damage repair and checkpoint gene panel including TP53. Sequencing results were correlated to clinicopathologic variables as well as PSA persistence or time to PSA failure. In addition, the distribution of TP53 and DNA damage repair gene mutations was analyzed in three large publicly available datasets (TCGA, MSKCC and SU2C).

RESULTS

Of 68 primary prostate cancers analyzed, 23 (33.8%) were found to harbor a mutation in either TP53 (n = 12, 17.6%) or a DNA damage repair gene (n = 11, 16.2%). The vast majority of these mutations (22 of 23, 95.7%) were detected in primary tumors from patients with high-risk features. These mutations were mutually exclusive in our cohort and additional data mining suggests an enrichment of DNA damage repair gene mutations in TP53 wild-type tumors. Mutations in either TP53 or a DNA damage repair gene were associated with a significantly worse prognosis after RPX. Importantly, the presence of TP53/DNA damage repair gene mutations was an independent risk factor for PSA failure or PSA persistence in multivariate Cox regression models.

CONCLUSION

TP53 or DNA damage repair gene mutations are frequently detected in primary prostate cancer with high-risk features and define a subgroup of patients with an increased risk for PSA failure or persistence after RPX. The significant adverse impact of these alterations on patient prognosis may be exploited to identify men with prostate cancer who may benefit from a more intensified treatment.

Lutetium-177 Labelled PSMA Targeted Therapy in Advanced Prostate Cancer: Current Status and Future Perspectives

Patients suffering from metastatic castration-resistant prostate cancer (mCRPC) have a poor prognosis. As a further treatment option ¹⁷⁷Lutetium (Lu) prostate-specific membrane antigen (PSMA) radioligand therapy gained a significant interest of many investigators. Several publications showed great response and prolonged survival with limited adverse events. However, to this point, it still remains unclear which patients benefit the most from ¹⁷⁷Lu-PSMA therapy, and how to improve the treatment regimen to achieve best outcome while minimizing potential adverse events. The efficacy for mCRPC patients is a given fact, and with the newly published results of the VISION trial its approval is only a matter of time. Recently, investigators started to focus on treating prostate cancer patients in earlier disease stages and in combination with other compounds. This review gives a brief overview of the current state and the future perspectives of ¹⁷⁷Lu labelled PSMA radioligand therapy.

PARP-inhibitors in epithelial ovarian cancer: Actual positioning and future expectations

Poly-(ADP)-ribose polymerase inhibitors (PARPi) are a class of oral anticancer drugs first developed as "synthetically lethal" in cancers harboring BRCA1/BRCA2 inactivating mutations. In high-grade serous or endometrioid ovarian cancers (HGOC), PARPi demonstrated benefit as maintenance therapy in relapsing BRCA-mutated and non-mutated tumors. Recently, they extended their indications to frontline maintenance therapy. This review summarizes the current place of PARPi (i) as maintenance or single agent in recurrent disease and (ii) frontline maintenance with different settings. We reviewed the course of biomarker identification, the challenge of overcoming resistance to PARPi and future combinations with targeted therapies, including anti-angiogenic, immune checkpoint inhibitors and DNA damage response inhibitors.

25-year perspective on prostate cancer: Conquering frontiers and understanding tumor biology

Major changes in the field of prostate cancer over the last 25 years include the implementation of prostate specific antigen screening and the recognition that BRCA confers hereditary risk of prostate cancer. Quality of life and survivorship have driven risk stratification for localized prostate cancer, facilitated by molecular signatures and leading to increased acceptance of active surveillance as a mainstream treatment option. Advances in technology have improved efficacy and reduced toxicity in both radical prostatectomy and radiation therapy for localized prostate cancer. Improved understanding of the androgen receptor has yielded substantially more effective therapies. Future growth areas include personalized treatment based on genomic and genetic information, theranostics radiopharmaceuticals, and more aggressive treatment of metastatic disease to include focal therapy. Multidisciplinary management between specialized urologists, radiation oncologists, and medical oncologists remains central to maximizing patient outcomes.

Synthetic Lethality in Cancer Therapeutics: The Next Generation

Synthetic lethality (SL) provides a conceptual framework for tackling targets that are not classically "druggable," including loss-of-function mutations in tumor suppressor genes required for carcinogenesis. Recent technological advances have led to an inflection point in our understanding of genetic interaction networks and ability to identify a wide array of novel SL drug targets. Here, we review concepts and lessons emerging from first-generation trials aimed at testing SL drugs, discuss how the nature of the targeted lesion can influence therapeutic outcomes, and highlight the need to develop clinical biomarkers distinct from those based on the paradigms developed to target activated oncogenes. SIGNIFICANCE: SL offers an approach for the targeting of loss of function of tumor suppressor and DNA repair genes, as well as of amplification and/or overexpression of genes that cannot be targeted directly. A next generation of tumor-specific alterations targetable through SL has emerged from high-throughput CRISPR technology, heralding not only new opportunities for drug development, but also important challenges in the development of optimal predictive biomarkers.

Technical and biological constraints on ctDNA-based genotyping

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.

Pentz R. Prostate Cancer: Community Education and Disparities in Diagnosis and Treatment

Prostate cancer remains the leading diagnosed cancer and the second leading cause of death among American men. Despite improvements in screening modalities, diagnostics, and treatment, disparities exist among Black men in this country. The primary objective of this systematic review is to describe the reported disparities in screening, diagnostics, and treatments as well as efforts to alleviate these disparities through community and educational outreach efforts. Critical review took place of retrospective, prospective, and socially descriptive data of English language publications in the PubMed database. Despite more advanced presentation, lower rates of screening and diagnostic procedures, and low rates of trial inclusion, subanalyses have shown that various modalities of therapy are quite effective in Black populations. Moreover, patients treated on prospective clinical trials and within equal-access care environments have shown similar outcomes regardless of race. Additional prospective studies and enhanced participation in screening, diagnostic and genetic testing, clinical trials, and community-based educational endeavors are important to ensure equitable progress in prostate cancer for all patients. IMPLICATIONS FOR PRACTICE: Notable progress has been made with therapeutic advances for prostate cancer, but racial disparities continue to exist. Differing rates in screening and utility in diagnostic procedures play a role in these disparities. Black patients often present with more advanced disease, higher prostate-specific antigen, and other adverse factors, but outcomes can be attenuated in trials or in equal-access care environments. Recent data have shown that multiple modalities of therapy are quite effective in Black populations. Novel and bold hypotheses to increase inclusion in clinical trial, enhance decentralized trial efforts, and enact successful models of patient navigation and community partnership are vital to ensure continued progress in prostate cancer disparities.

Prostate Cancer Biomarkers: From diagnosis to prognosis and precision-guided therapeutics

Prostate cancer (PCa) is one of the most commonly diagnosed malignancies and among the leading causes of cancer-related death worldwide. It is a highly heterogeneous disease, ranging from remarkably slow progression or inertia to highly aggressive and fatal disease. As therapeutic decision-making, clinical trial design and outcome highly depend on the appropriate stratification of patients to risk groups, it is imperative to differentiate between benign versus more aggressive states. The incorporation of clinically valuable prognostic and predictive biomarkers is also potentially amenable in this process, in the timely prevention of metastatic disease and in the decision for therapy selection. This review summarizes the progress that has so far been made in the identification of the genomic events that can be used for the classification, prediction and prognostication of PCa, and as major targets for clinical intervention. We include an extensive list of emerging biomarkers for which there is enough preclinical evidence to suggest that they may constitute crucial targets for achieving significant advances in the management of the disease. Finally, we highlight the main challenges that are associated with the identification of clinically significant PCa biomarkers and recommend possible ways to overcome such limitations.

Basic Science and Molecular Genetics of Prostate Cancer Aggressiveness

Androgen receptor function, tumor cell plasticity, loss of tumor suppressors, and defects in DNA repair genes affect aggressive features of prostate cancer. Prostate cancer development, progression, and aggressive behavior are often attributable to function of the androgen receptor. Tumor cell plasticity, neuroendocrine features, and loss of tumor suppressors lend aggressive behavior to prostate cancer cells. DNA repair defects have ramifications for prostate cancer cell behavior.

High-Throughput Imaging Assay for Drug Screening of 3D Prostate Cancer Organoids

New treatments are required for advanced prostate cancer; however, there are fewer preclinical models of prostate cancer than other common tumor types to test candidate therapeutics. One opportunity to increase the scope of preclinical studies is to grow tissue from patient-derived xenografts (PDXs) as organoid cultures. Here we report a scalable pipeline for automated seeding, treatment and an analysis of the drug responses of prostate cancer organoids. We established organoid cultures from 5 PDXs with diverse phenotypes of prostate cancer, including castrate-sensitive and castrate-resistant disease, as well as adenocarcinoma and neuroendocrine pathology. We robotically embedded organoids in Matrigel in 384-well plates and monitored growth via brightfield microscopy before treatment with poly ADP-ribose polymerase inhibitors or a compound library. Independent readouts including metabolic activity and live-cell imaging–based features provided robust measures of organoid growth and complementary ways of assessing drug efficacy. Single organoid analyses enabled in-depth assessment of morphological differences between patients and within organoid populations and revealed that larger organoids had more striking changes in morphology and composition after drug treatment. By increasing the scale and scope of organoid experiments, this automated assay complements other patient-derived models and will expedite preclinical testing of new treatments for prostate cancer.

Genetically Informed Prostate Cancer Screening

Prostate cancer represents a significant health care burden in the United States due to its incidence, treatment-related morbidity, and cancer-specific mortality. The burden begins with prostate-specific antigen screening, which has been subject to controversy due to concerns of overdiagnosis and overtreatment. Advancements in molecular oncology have provided evidence for the inherited predisposition to prostate cancer, which could improve individualized, risk-adapted approaches to screening and mitigate the harms of routine screening. This review presents the current evidence for the genetic basis of prostate cancer and novel genetically informed, risk-adapted screening strategies for prostate cancer.

Recent Development and Future Prospects of Molecular Targeted Therapy in Prostate Cancer

Prostate cancer (PC) is a rapidly increasing ailment worldwide. The previous decade has observed a rapid advancement in PC therapies that was evident from the number of FDA approvals during this phase. Androgen deprivation therapies (ADT) have traditionally remained a mainstay for the management of PCs, but the past decade has experienced the emergence of newer classes of drugs that can be used with or without the administration of ADT. FDA approved poly (ADP-ribose) polymerase inhibitors (PARPi), such as olaparib and rucaparib, after successful clinical trials against gene-mutated metastatic castration-resistant prostate cancer. Furthermore, drugs like apalutamide, darolutamide, and enzalutamide with an androgen-targeted mechanism of action have manifested superior results in non-metastatic castration-resistant prostate cancer (nmCRPC), metastatic castration-sensitive prostate cancer (mCSPC), and metastatic castration-resistant prostate cancer (mCRPC), respectively, with or without previously administered docetaxel. Relugolix, an oral gonadotropin-releasing hormone antagonist, and a combination of abiraterone acetate plus prednisone were also approved by FDA after a successful trial in advanced PC and mCRPC, respectively. This review aims to analyze the FDA-approved agents in PC during the last decade and provide a summary of their clinical trials. It also presents an overview of the ongoing progress of prospective molecules still under trial.

Precision Medicine in Oncology: A Review of Multi-Tumor Actionable Molecular Targets with an Emphasis on Non-Small Cell Lung Cancer

Precision medicine is essential for the modern care of a patient with cancer. Comprehensive molecular profiling of the tumor itself is necessary to determine the presence or absence of certain targetable abnormalities or biomarkers. In particular, lung cancer is a disease for which targetable genomic alterations will soon guide therapy in the majority of cases. In this comprehensive review of solid tumor-based biomarkers, we describe the genomic alterations for which targeted agents have been approved by the United States Food and Drug Administration (FDA). While focusing on alterations leading to approvals in a tumor-agnostic fashion (MSI-h, TMB-h, NTRK) and on those alterations with approvals in multiple malignancies (BRAF, ERBB2, RET, BRCA, PD-L1), we also describe several biomarkers or indications that are likely to lead to an approved drug in the near future (e.g., KRAS G12C, PD-L1 amplification, HER2 overexpression in colon cancer, HER2 mutations in lung cancer). Finally, we detail the current landscape of additional actionable alterations (EGFR, ALK, ROS1, MET) in lung cancer, a biomarker-rich malignancy that has greatly benefitted from the precision oncology revolution.

Concordance of DNA Repair Gene Mutations in Paired Primary Prostate Cancer Samples and Metastatic Tissue or Cell-Free DNA

IMPORTANCE

DNA damage repair (DDR) gene mutations represent actionable alterations that can guide precision medicine strategies for advanced prostate cancer. However, acquisition of contemporary tissue samples for molecular testing can be a barrier to deploying precision medicine approaches. We hypothesized that most DDR alterations represent truncal events in prostate cancer and that primary tissue would faithfully reflect mutations found in cell-free circulating tumor DNA (ctDNA) and/or metastatic tissue.

OBJECTIVE

To assess concordance in DDR gene alterations between primary prostate cancer and metastases or ctDNA specimens.

DESIGN, SETTING, AND PARTICIPANTS

Patients were included if a DDR pathway mutation was detected in metastatic tissue or ctDNA and primary tissue sequencing was available for comparison. Sequencing data from 3 cohorts were analyzed: (1) FoundationOne, (2) University of Washington clinical cases (University of Washington-OncoPlex or Stand Up to Cancer-Prostate Cancer Foundation International Dream Team sequencing pipelines), and (3) University of Washington rapid autopsy series. Only pathogenic somatic mutations were included, and more than 30 days between primary tumor tissue and ctDNA and/or metastatic tissue acquisition was required. Clonal hematopoiesis of indeterminate potential (CHIP) and germline events were adjudicated by an expert molecular pathologist and excluded.

MAIN OUTCOMES AND MEASURES

The DDR gene alterations detected in primary prostate tissue matched with metastatic tissue and/or ctDNA findings.

RESULTS

A total of 72 men with known DDR alterations were included in the analysis, and primary samples with paired ctDNA and/or metastatic tissue were sequenced. After excluding patients with ctDNA where only CHIP and/or germline events (n = 21) were observed, 51 patients remained and were included in the final analysis. The median (range) time from acquisition of primary tissue to acquisition of ctDNA or tumor tissue was 55 (5-193) months. Concordance in DDR gene mutation status across samples was 84% (95% CI, 71%-92%). Rates of concordance between metastatic-primary and ctDNA-primary pairs were similar when patients with CHIP events were excluded. Multiclonal BRCA2 reversion mutations associated with resistance to PARP inhibitors and platinum chemotherapy were detected in ctDNA from 2 patients.

CONCLUSIONS AND RELEVANCE

In this genetic association study of 3 patient cohorts, primary prostate tissue accurately reflected the mutational status of actionable DDR genes in metastatic tissue, consistent with DDR alterations being truncal in most patients. After excluding likely CHIP events, ctDNA profiling accurately captured these DDR mutations while also detecting reversion alterations that may suggest resistance mechanisms.

Homologous recombination deficiency (HRD) score in germline BRCA2- versus ATM-altered prostate cancer

The homologous recombination deficiency (HRD) score integrates three DNA-based measures of genomic instability, and has been understudied in prostate cancer. Given the recent FDA approval of two PARP inhibitors for prostate cancer, HRD score analysis could help to refine treatment selection. We assessed HRD score (defined as the sum of loss-of-heterozygosity, telomeric allelic imbalance, and large-scale state transitions) in three cohorts of primary prostate cancer, including a Johns Hopkins University (JHU) cohort with germline mutations in BRCA2, ATM, or CHEK2 (n = 64), the TCGA cohort (n = 391), and the PROGENE cohort (n = 102). In the JHU cohort, tumors with germline BRCA2 mutations had higher HRD scores (median = 27) than those with germline ATM or CHEK2 mutations (median = 16.5 [p = 0.029] and 9 [p < 0.001], respectively). For TCGA tumors without underlying HR pathway mutations, the median HRD score was 11, significantly lower than ovarian carcinoma lacking BRCA1/2 mutations (median = 28). In the absence of HR gene mutations, the median HRD score was unexpectedly higher among prostate cancers with TP53 mutations versus those without (17 vs. 11; p = 0.015); this finding was confirmed in the PROGENE cohort (24 vs. 16; p = 0.001). Finally, among eight BRCA2-altered patients who received olaparib, progression-free survival trended longer in those with HRD scores above versus below the median (14.9 vs. 9.9 months). We conclude that HRD scores are low in primary prostate cancer and higher in cases with germline BRCA2 or somatic TP53 mutations. Germline BRCA2-altered cases have significantly higher HRD scores than germline ATM-altered or CHEK2-altered cases, consistent with the lower efficacy of PARP inhibitors among the latter.

Beyond the Androgen Receptor: The Sequence, the Mutants, and New Avengers in the Treatment of Castrate-Resistant Metastatic Prostate Cancer

Targeting the androgen receptor by depriving testosterone with gonadotropin-releasing hormone agonists or antagonists, or surgical castration, has been the backbone of metastatic prostate cancer treatment. Although most prostate cancers initially respond to androgen deprivation, metastatic castration-resistant prostate cancer evolves into a heterogeneous disease with diverse drivers of progression and mechanisms of therapeutic resistance. Development of castrate resistance phenotype is associated with lethality despite the recent noteworthy strides gained via increase in therapeutic options. Identification of novel therapeutics to further improve survival and achieve durable responses in metastatic castration-resistant prostate cancer is a clinical necessity. In this review, we outline the existing avengers for treatment of metastatic castration-resistant prostate cancer by clinical presentation, placing into context the clinical state of the patient, such as burden of disease and symptoms. Doing so might aid in the ability to optimize the sequence of agents and allow for maximal exposure to life-prolonging therapeutics. Realizing the limitations of the androgen signaling inhibition, we explore the androgen-indifferent prostate cancer: the mutants. Classically, these subtypes have been associated with variant histology, but androgen-indifferent prostate cancer features are now frequently observed in association with heterogeneous morphologies, including double-negative prostate cancers, lacking both androgen receptor and neuroendocrine features, or clinicopathologic criteria, such as the aggressive variant prostate cancer criteria. The framework of new avengers against metastatic castration-resistant prostate cancer based on mechanism, including DNA repair, immune checkpoint inhibition, PTEN/PI3K/AKT pathway, prostate-specific membrane antigen targets, bispecific T-cell engagers, and radionuclide therapies, is summarized in this review.

How I Treat Metastatic Hormone-Sensitive Prostate Cancer?

Androgen deprivation therapy (ADT) combined with docetaxel or antiandrogens (abiraterone, enzalutamide, or apalutamide) improved the outcomes in men with metastatic hormone-sensitive prostate cancer (mHSPC). When multiple options are available, the dilemma remains how to choose among these options. Similarly, issues of bone health, long-term side effects of therapies, and hereditary risk need to be discussed for comprehensive care. In the present article, we reviewed the relevant evidence for the treatment of mHSPC. ADT alone is not the current standard of care for most patients. In these times of plenty and price crisis, it is imperative to find the best option for treating these patients.

TPX2 Enhanced the Activation of the HGF/ETS-1 Pathway and Increased the Invasion of Endocrine-Independent Prostate Carcinoma Cells

The prognosis for endocrine-independent prostate carcinoma is still poor due to its highly metastatic feature. In the present work, TPX2 (the targeting protein for Xklp2), which is known as a micro-tubulin interacted protein, was identified as a novel coactivator of ETS-1, a transcription factor that plays a central role in mediating the metastasis of human malignancies. TPX2 enhanced the transcription factor activation of ETS-1 and increased the expression of ETS-1's downstream metastasis-related genes, such as mmp3 or mmp9, induced by HGF (hepatocyte growth factor), a typical agonist of the HGF/c-MET/ETS-1 pathway. The protein-interaction between TPX2 and ETS-1 was examined using immunoprecipitation (IP). TPX2 enhanced the accumulation of ETS-1 in the nuclear and the recruitment of its binding element (EST binding site, EBS) located in the promoter region of its downstream gene, mmp9. Moreover, TPX2 enhanced the in vitro or in vivo invasion of a typical endocrine-independent prostate carcinoma cell line, PC-3. Therefore, TPX2 enhanced the activation of the HGF/ETS-1 pathway to enhance the invasion of endocrine-independent prostate carcinoma cells and thus it would be a promising target for prostate carcinoma treatment.

Circulating Tumor DNA Testing for Homology Recombination Repair Genes in Prostate Cancer: From the Lab to the Clinic

Approximately 23% of metastatic castration-resistant prostate cancers (mCRPC) harbor deleterious aberrations in DNA repair genes. Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) therapy has shown improvements in overall survival in patients with mCRPC who harbor somatic and/or germline alterations of homology recombination repair (HRR) genes. Peripheral blood samples are typically used for the germline mutation analysis test using the DNA extracted from peripheral blood leucocytes. Somatic alterations can be assessed by extracting DNA from a tumor tissue sample or using circulating tumor DNA (ctDNA) extracted from a plasma sample. Each of these genetic tests has its own benefits and limitations. The main advantages compared to the tissue test are that liquid biopsy is a non-invasive and easily repeatable test with the value of better representing tumor heterogeneity than primary biopsy and of capturing changes and/or resistance mutations in the genetic tumor profile during disease progression. Furthermore, ctDNA can inform about mutation status and guide treatment options in patients with mCRPC. Clinical validation and test implementation into routine clinical practice are currently very limited. In this review, we discuss the state of the art of the ctDNA test in prostate cancer compared to blood and tissue testing. We also illustrate the ctDNA testing workflow, the available techniques for ctDNA extraction, sequencing, and analysis, describing advantages and limits of each techniques.

A Case-Based Clinical Approach to the Investigation, Management and Screening of Families with BRCA2 Related Prostate Cancer

BRCA2 is the most commonly implicated DNA damage repair gene associated with inherited prostate cancer. BRCA2 deficient prostate cancer typically presents at a younger age, is more poorly differentiated, and is associated with worse survival outcomes than non-BRCA2 associated prostate cancer. Despite these unfavourable prognostic implications, poly-ADP ribose polymerase inhibitors and platinum-based chemotherapy have been identified as potent targeted therapeutic agents towards BRCA1/2 deficient cancer cells. This review article explores the literature surrounding BRCA2-related prostate cancer through a familial clinical scenario. The investigation, diagnosis and management of BRCA2 deficient prostate cancer will be explored, alongside the implications of the identification of a germline pathogenic BRCA2 variant within a family, cascade screening and prostate cancer surveillance in unaffected male BRCA2 carriers. A greater understanding of the molecular pathogenesis of DNA damage repair gene deficient prostate cancer, coupled with new treatment paradigms and widened access to both somatic and germline genetic analysis for prostate cancer patients and their families will hopefully enable the robust implementation of high quality evidence-based clinical pathways for both the management and identification of BRCA2 deficient prostate cancer and improved screening, early detection and prevention strategies for individuals at increased genetic risk of prostate cancer.

BRCA Germline Mutations in Prostate Cancer: The Future Is Tailored

Prostate cancer (PCa) is the second most common neoplasm in men and the fifth leading cause of death worldwide [...].

The role of PARP inhibitors in BRCA mutated pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) accounts for about 3% of all cancers in the United States and about 7% of all cancer deaths. Despite the lower prevalence relative to other solid tumors, it is one of the leading causes of cancer-related death in the US. PDAC is highly resistant to chemotherapy as well as radiation therapy. Current standard-of-care chemotherapeutic regimens provide transient disease control but eventually tumors develop chemoresistance. Tumors that are deficient in DNA damage repair mechanisms such as BRCA mutants respond better to platinum-based chemotherapies. However, these tumor cells can utilize the poly adenosine diphosphate (ADP)-ribose polymerase (PARP) as a salvage DNA repair pathway to prolong survival. Hence, in the presence of BRCA mutations, the inhibition of the PARP pathway can lead to tumor cell death. This provides the rationale for using PARP inhibitors in patients with BRCA mutated PDAC. The phase III POLO trial showed a near doubling of progression-free survival (PFS) compared with placebo in advanced PDAC when a PARP inhibitor, olaparib, was used as maintenance therapy. As a result, the US Food and Drug Administration (FDA) approved olaparib as a maintenance treatment for germline BRCA mutated advanced PDAC that has not progressed on platinum-based chemotherapy. The success of olaparib in treating advanced PDAC opened the new field for utilizing PARP inhibitors in patients with DNA damage repair (DDR) gene defects. Currently, many clinical trials with various PARP inhibitors are ongoing either as monotherapy or in combination with other agents. In addition to germline/somatic BRCA mutations, some trials are enrolling patients with defects in other DDR genes such as ATM, PALB2, and CHEK2. With many ongoing PARP inhibitor trials, it is hopeful that the management of PDAC will continuously evolve and eventually lead to improved patient outcomes.

Germline Genetics of Prostate Cancer: Prevalence of Risk Variants and Clinical Implications for Disease Management

Prostate cancer has entered into the era of precision medicine with the recent approvals of targeted therapeutics (olaparib and rucaparib). The presence of germline mutations has important hereditary cancer implications for patients with prostate cancer, and germline testing is increasingly important in cancer screening, risk assessment, and the overall treatment and management of the disease. In this review, we discuss germline variants associated with inherited predisposition, prostate cancer risk and outcomes. We review recommendations for germline testing, available testing platforms, genetic counseling as well as discuss the therapeutic implications of germline variants relevant to prostate cancer treatments. Understanding the role of germline (heritable) mutations that affect prostate cancer biology and risk as well as the subsequent effect of these alterations on potential therapies is critical as the treatment paradigm shifts towards precision medicine. Furthermore, enhancing patient education tactics and healthcare system infrastructure is essential for the utilization of relevant predictive biomarkers and the improvement of clinical outcomes of patients with prostate cancer or at high risk of developing the disease.

Real-world genetic testing patterns in metastatic castration-resistant prostate cancer

Aim: To assess the patterns of genetic testing for homologous recombination repair mutations in patients with metastatic castration-resistant prostate cancer (mCRPC) pre-PARP inhibitors approval. Patients & methods: mCRPC patients were selected in an oncology electronic medical records database. Patterns and predictors of testing for ATM, BRCA1/2, CDK12, PALB2 and FANCA gene alterations were assessed. Results: Of 5213 mCRPC patients, 674 (13%) had a documented genetic test. The number of tested patients increased from 1 in 2013 to 313 in 2018 (out of 3161 and 3010 clinically active patients, respectively). Receiving care in an academic oncology center (versus a community-based center) strongly predicted genetic testing (hazard ratio = 2.41). Conclusion: The use of and access to genetic testing pre-PARP inhibitor approval was suboptimal.

Genomic Correlates of DNA Damage in Breast Cancer Subtypes

Simple Summary

Breast cancer (BC) is the most common invasive tumor in women and the second leading cause of cancer-related death. Therefore, identification of druggable targets to improve current therapies and overcome resistance is a major goal. In this work, we performed an in silico analysis of transcriptomic datasets in breast cancer, and focused on those involved in DNA damage, as were clearly upregulated using gene set enrichment analyses (GSEA), particular the following pathways: ATM/ATR, BARD1 and Fanconi Anemia. BHLHE40, RFWD2, BRIP1, PRKDC, NBN, RNF8, FANCD2, RAD1, BLM, DCLRE1C, UBE2T, CSTF1, MCM7, RFC4, YWHAB, YWHAZ, CDC6, CCNE1, and FANCI genes were amplified/overexpressed in BC, and correlated with detrimental prognosis. Finally, we selected the best transcriptomic signature of genes within this function that associated with clinical outcome to identify functional genomic correlates of outcome.

Abstract

Among the described druggable vulnerabilities, acting on the DNA repair mechanism has gained momentum, with the approval of PARP inhibitors in several indications, including breast cancer. However, beyond the mere presence of BRCA1/BRCA2 mutations, the identification of additional biomarkers that would help to select tumors with an extreme dependence on DNA repair machinery would help to stratify therapeutic decisions. Gene set enrichment analyses (GSEA) using public datasets evaluating expression values between normal breast tissue and breast cancer identified a set of upregulated genes. Genes included in different pathways, such as ATM/ATR, BARD1, and Fanconi Anemia, which are involved in the DNA damage response, were selected and confirmed using molecular alterations data contained at cBioportal. Nineteen genes from these gene sets were identified to be amplified and upregulated in breast cancer but only five of them NBN, PRKDC, RFWD2, UBE2T, and YWHAZ meet criteria in all breast cancer molecular subtypes. Correlation of the selected genes with prognosis (relapse free survival, RFS, and overall survival, OS) was performed using the KM Plotter Online Tool. In last place, we selected the best signature of genes within this process whose upregulation can be indicative of a more aggressive phenotype and linked with worse outcome. In summary, we identify genomic correlates within DNA damage pathway associated with prognosis in breast cancer.

Plasma Cell-Free DNA Profiling of PTEN-PI3K-AKT Pathway Aberrations in Metastatic Castration-Resistant Prostate Cancer

Tumor tissue from metastatic castration-resistant prostate cancer (mCRPC) harbors frequent copy number variations (CNVs) in the PTEN-PI3K-AKT pathway. However, identifying CNVs in plasma cell-free DNA (cfDNA) has proven to be challenging. With emerging data supporting Akt inhibition in PTEN-deficient mCRPC, we profiled PTEN-PI3K-AKT pathway aberrations in patients with mCRPC using a novel cfDNA assay optimized for CNV detection.

METHODS

A next-generation sequencing-based cfDNA assay was used to profile 231 patients with mCRPC from two independent cohorts (Australian, n = 78; United States, n = 153). PTEN-PI3K-AKT pathway genomic aberrations were correlated with clinical outcomes, including progression-free survival and overall survival (OS).

RESULTS

PTEN loss and PIK3CA gain were detected in 37% (85 of 231) and 17% (39 of 231) of patients, respectively. Poorer outcomes were observed in patients with PTEN-PI3K-AKT pathway aberrations, including those with dual PTEN loss and PIK3CA gain (hazard ratio 2.3, 95% CI 1.2 to 4.4). Cumulative CNV burden in the PTEN-PI3K-AKT and androgen receptor (AR) pathways was associated with significantly worse clinical outcomes (0 v 1 v ≥ 2 CNVs in Australian cohort: median OS 33.5 v 17.2 v 9.7 months, P < .001; 0 v 1 v ≥ 2 CNVs in US cohort: median OS 35.5 v 14.3 v 9.2 months, P < .001). Notably, 21% (31 of 146) of PTEN-neutral patients harbored alternative PTEN-PI3K-AKT pathway aberrations.

CONCLUSION

PTEN-PI3K-AKT pathway CNVs were readily detected using our cfDNA assay, with the prevalence of PTEN loss comparable with tissue-based studies. Additional PTEN-PI3K-AKT pathway aberrations were found in one fifth of PTEN-neutral cases. Concurrent CNVs in the PTEN-PI3K-AKT and AR pathways portended poor survival, and identifying this high-risk patient subset for dual AR/Akt inhibition may optimize precision treatment with Akt inhibitors in mCRPC.

Prostate cancer and PARP inhibitors: progress and challenges

Despite survival improvements achieved over the last two decades, prostate cancer remains lethal at the metastatic castration-resistant stage (mCRPC) and new therapeutic approaches are needed. Germinal and/or somatic alterations of DNA-damage response pathway genes are found in a substantial number of patients with advanced prostate cancers, mainly of poor prognosis. Such alterations induce a dependency for single strand break reparation through the poly(adenosine diphosphate-ribose) polymerase (PARP) system, providing the rationale to develop PARP inhibitors. In solid tumors, the first demonstration of an improvement in overall survival was provided by olaparib in patients with mCRPC harboring homologous recombination repair deficiencies. Although this represents a major milestone, a number of issues relating to PARP inhibitors remain. This timely review synthesizes and discusses the rationale and development of PARP inhibitors, biomarker-based approaches associated and the future challenges related to their prescription as well as patient pathways.

Olaparib for the treatment of metastatic prostate cancer

Recent innovations in the treatment of metastatic prostate cancer have improved patient outcomes. Nonetheless, this disease remains fatal and additional treatment approaches are needed. Greater understanding of the molecular landscape of metastatic prostate cancer has revealed recurrent alterations in key pathways amenable to therapeutic targeting. One such pathway is DNA repair, particularly alterations in genes directly or indirectly associated with homologous recombination repair found in up to one-quarter of patients with metastatic castrate-resistant prostate cancer (mCRPC). Olaparib, an inhibitor of poly-ADP-ribose polymerase, has recently gained approval for the treatment of mCRPC harboring alterations in homologous recombination repair genes. This review will provide a summary of evidence regarding PARP inhibition in the treatment of mCRPC, with a specific focus on olaparib.

Novel Strategies for Treating Castration-Resistant Prostate Cancer

The development of castration resistance is an inevitable pathway for the vast majority of patients with advanced prostate cancer. Recently, there have been significant breakthroughs in the understanding and management options of castration-resistant prostate cancer. Three novel hormonal agents showed survival benefits in non-metastatic patients. As for metastatic disease, there was an even wider range of management options being investigated. This review summarized advances in the management of castration-resistant prostate cancer (CRPC) including emerging data on novel imaging techniques and treatment strategies.

Treatment and Patient Selection for Patients with Metastatic Castration-resistant Prostate After Progression on Docetaxel and Abiraterone/Enzalutamide: When to Play Your CARD and When to Do Your PARP

For patients with metastatic castration-resistant prostate cancer (mCRPC) progressing after an androgen receptor axis-targeted therapy and docetaxel, poly (ADP-ribose) polymerase (PARP) inhibitors and chemotherapy with cabazitaxel have shown promise. We address the trials for the two approaches and consider possible sequencing of these drugs. We suggest that only patients with a BRCA2 mutation should receive a PARP inhibitor, and docetaxel or cabazitaxel should be favored in the absence of BRCA2 alterations, provided the patient is naïve to these drugs.

Niraparib with androgen receptor-axis-targeted therapy in patients with metastatic castration-resistant prostate cancer: safety and pharmacokinetic results from a phase 1b study (BEDIVERE)

Purpose

To assess the safety and pharmacokinetics and determine the recommended phase 2 dose (RP2D) of niraparib with apalutamide or abiraterone acetate plus prednisone (AAP) in patients with metastatic castration-resistant prostate cancer (mCRPC).

Methods

BEDIVERE was a multicenter, open-label, phase 1b study of niraparib 200 or 300 mg/day with apalutamide 240 mg or AAP (abiraterone acetate 1000 mg; prednisone 10 mg). Patients with mCRPC were previously treated with ≥ 2 lines of systemic therapy, including ≥ 1 androgen receptor-axis-targeted therapy for prostate cancer.

Results

Thirty-three patients were enrolled (niraparib-apalutamide, 6; niraparib-AAP, 27). No dose-limiting toxicities (DLTs) were reported when combinations included niraparib 200 mg; five patients receiving niraparib 300 mg experienced DLTs [niraparib-apalutamide, 2/3 patients (66.7%); niraparib-AAP, 3/8 patients (37.5%)]. Although data are limited, niraparib exposures were lower when given with apalutamide compared with historical niraparib monotherapy exposures in patients with solid tumors. Because of the higher incidence of DLTs, the niraparib–apalutamide combination and niraparib 300 mg combination with AAP were not further evaluated. Niraparib 200 mg was selected as the RP2D with AAP. Of 19 patients receiving niraparib 200 mg with AAP, 12 (63.2%) had grade 3/4 treatment-emergent adverse events, the most common being thrombocytopenia (26.3%) and hypertension (21.1%). Five patients (26.3%) had adverse events leading to treatment discontinuation.

Conclusions

These results support the choice of niraparib 200 mg as the RP2D with AAP. The niraparib–AAP combination was tolerable in patients with mCRPC, with no new safety signals. An ongoing phase 3 study is further assessing this combination in patients with mCRPC.

Trial registration no.

NCT02924766 (ClinicalTrials.gov).

Supplementary Information

The online version contains supplementary material available at 10.1007/s00280-021-04249-7.

Alternative Non-Homologous End-Joining: Error-Prone DNA Repair as Cancer's Achilles' Heel

Simple Summary

Cancer onset and progression lead to a high rate of DNA damage, due to replicative and metabolic stress. To survive in this dangerous condition, cancer cells switch the DNA repair machinery from faithful systems to error-prone pathways, strongly increasing the mutational rate that, in turn, supports the disease progression and drug resistance. Although DNA repair de-regulation boosts genomic instability, it represents, at the same time, a critical cancer vulnerability that can be exploited for synthetic lethality-based therapeutic intervention. We here discuss the role of the error-prone DNA repair, named Alternative Non-Homologous End Joining (Alt-NHEJ), as inducer of genomic instability and as a potential therapeutic target. We portray different strategies to drug Alt-NHEJ and discuss future challenges for selecting patients who could benefit from Alt-NHEJ inhibition, with the aim of precision oncology.

Abstract

Error-prone DNA repair pathways promote genomic instability which leads to the onset of cancer hallmarks by progressive genetic aberrations in tumor cells. The molecular mechanisms which foster this process remain mostly undefined, and breakthrough advancements are eagerly awaited. In this context, the alternative non-homologous end joining (Alt-NHEJ) pathway is considered a leading actor. Indeed, there is experimental evidence that up-regulation of major Alt-NHEJ components, such as LIG3, PolQ, and PARP1, occurs in different tumors, where they are often associated with disease progression and drug resistance. Moreover, the Alt-NHEJ addiction of cancer cells provides a promising target to be exploited by synthetic lethality approaches for the use of DNA damage response (DDR) inhibitors and even as a sensitizer to checkpoint-inhibitors immunotherapy by increasing the mutational load. In this review, we discuss recent findings highlighting the role of Alt-NHEJ as a promoter of genomic instability and, therefore, as new cancer’s Achilles’ heel to be therapeutically exploited in precision oncology.

Association between BRCA2 alterations and intraductal and cribriform histologies in prostate cancer

BACKGROUND

Intraductal (IDC) and cribriform (CRIB) histologies in prostate cancer have been associated with germline BRCA2 (gBRCA2) mutations in small retrospective series, leading to the recommendation of genetic testing for patients with IDC in the primary tumour.

PATIENTS AND METHODS

To examine the association of gBRCA2 mutations and other tumour molecular features with IDC and/or cribriform (CRIB) histologies, we conducted a case-control study in which primary prostate tumours from 58 gBRCA2 carriers were matched (1:2) by Gleason Grade Group and specimen type to 116 non-carriers. Presence/absence of IDC and CRIB morphologies was established by two expert uropathologists blinded to gBRCA2 status. Fluorescent in-situ hybridization (FISH) and next-generation sequencing (NGS) were used to detect BRCA2 alterations, PTEN deletions and TMPRSS2-ERG fusions. Chi-squared tests were used to compare the frequency of IDC and CRIB in gBRCA2 carriers and controls and to assess associations with other variables. Logistic regression models were constructed to identify independent factors associated with both histology patterns.

RESULTS

No significant differences between gBRCA2 carriers and non-carriers were observed in the prevalence of IDC (36% gBRCA2 versus 50% non-carriers, p = 0.085) or CRIB (53% gBRCA2 versus 43% non-carriers p = 0.197) patterns. However, IDC histology was independently associated with bi-allelic BRCA2 alterations (OR 4.3, 95%CI 1.1-16.2) and PTEN homozygous loss (OR 5.2, 95%CI 2.1-13.1). CRIB morphology was also independently associated with bi-allelic BRCA2 alterations (OR 5.6, 95%CI 1.7-19.3).

CONCLUSIONS

While we found no association between gBRCA2 mutations and IDC or CRIB histologies, bi-allelic BRCA2 loss in primary prostate tumours was significantly associated with both variant morphologies, independently of other clinical-pathologic factors.

Diagnostic Strategies for Treatment Selection in Advanced Prostate Cancer

Prostate Cancer (PCa) is a leading cause of morbidity and mortality among men worldwide. For most men with PCa, their disease will follow an indolent course. However, advanced PCa is associated with poor outcomes. There has been an advent of new therapeutic options with proven efficacy for advanced PCa in the last decade which has improved survival outcomes for men with this disease. Despite this, advanced PCa continues to be associated with a high rate of death. There is a lack of strong evidence guiding the timing and sequence of these novel treatment strategies. This paper focuses on a review of the strategies for diagnostic and the current evidence available for treatment selection in advanced PCa.

Prostate cancer

Prostate cancer is a complex disease that affects millions of men globally, predominantly in high human development index regions. Patients with localized disease at a low to intermediate risk of recurrence generally have a favourable outcome of 99% overall survival for 10 years if the disease is detected and treated at an early stage. Key genetic alterations include fusions of TMPRSS2 with ETS family genes, amplification of the MYC oncogene, deletion and/or mutation of PTEN and TP53 and, in advanced disease, amplification and/or mutation of the androgen receptor (AR). Prostate cancer is usually diagnosed by prostate biopsy prompted by a blood test to measure prostate-specific antigen levels and/or digital rectal examination. Treatment for localized disease includes active surveillance, radical prostatectomy or ablative radiotherapy as curative approaches. Men whose disease relapses after prostatectomy are treated with salvage radiotherapy and/or androgen deprivation therapy (ADT) for local relapse, or with ADT combined with chemotherapy or novel androgen signalling-targeted agents for systemic relapse. Advanced prostate cancer often progresses despite androgen ablation and is then considered castration-resistant and incurable. Current treatment options include AR-targeted agents, chemotherapy, radionuclides and the poly(ADP-ribose) inhibitor olaparib. Current research aims to improve prostate cancer detection, management and outcomes, including understanding the fundamental biology at all stages of the disease.

Prostate cancer

Prostate cancer is a complex disease that affects millions of men globally, predominantly in high human development index regions. Patients with localized disease at a low to intermediate risk of recurrence generally have a favourable outcome of 99% overall survival for 10 years if the disease is detected and treated at an early stage. Key genetic alterations include fusions of TMPRSS2 with ETS family genes, amplification of the MYC oncogene, deletion and/or mutation of PTEN and TP53 and, in advanced disease, amplification and/or mutation of the androgen receptor (AR). Prostate cancer is usually diagnosed by prostate biopsy prompted by a blood test to measure prostate-specific antigen levels and/or digital rectal examination. Treatment for localized disease includes active surveillance, radical prostatectomy or ablative radiotherapy as curative approaches. Men whose disease relapses after prostatectomy are treated with salvage radiotherapy and/or androgen deprivation therapy (ADT) for local relapse, or with ADT combined with chemotherapy or novel androgen signalling-targeted agents for systemic relapse. Advanced prostate cancer often progresses despite androgen ablation and is then considered castration-resistant and incurable. Current treatment options include AR-targeted agents, chemotherapy, radionuclides and the poly(ADP-ribose) inhibitor olaparib. Current research aims to improve prostate cancer detection, management and outcomes, including understanding the fundamental biology at all stages of the disease.

NCCN Guidelines Insights: Prostate Cancer, Version 1.2021

The NCCN Guidelines for Prostate Cancer address staging and risk assessment after a prostate cancer diagnosis and include management options for localized, regional, and metastatic disease. Recommendations for disease monitoring and treatment of recurrent disease are also included. The NCCN Prostate Cancer Panel meets annually to reevaluate and update their recommendations based on new clinical data and input from within NCCN Member Institutions and from external entities. This article summarizes the panel’s discussions for the 2021 update of the guidelines with regard to systemic therapy for metastatic castration-resistant prostate cancer.

Genetic aberrations in DNA repair pathways: a cornerstone of precision oncology in prostate cancer

Over the past years, several studies have demonstrated that defects in DNA damage response and repair (DDR) genes are present in a significant proportion of patients with prostate cancer. These alterations, particularly mutations in BRCA2, are known to be associated with an increased risk of developing prostate cancer and more aggressive forms of the disease. There is growing evidence that certain DDR gene aberrations confer sensitivity to poly-(ADP ribose) polymerase inhibitors and/or platinum chemotherapy, while other defects might identify cases that are more likely to benefit from immune checkpoint inhibition. The potential prognostic impact and relevance for treatment selection together with the decreasing costs and broader accessibility to next-generation sequencing have already resulted in the increased frequency of genetic profiling of prostate tumours. Remarkably, almost half of all DDR genetic defects can occur in the germline, and prostate cancer patients identified as mutation carriers, as well as their families, will require appropriate genetic counselling. In this review, we summarise the current knowledge regarding the biology and clinical implications of DDR defects in prostate cancer, and outline how this evidence is prompting a change in the treatment landscape of the disease.

Phycocyanin from Arthrospira platensis as Potential Anti-Cancer Drug: Review of In Vitro and In Vivo Studies

The application of cytostatic drugs or natural substances to inhibit cancer growth and progression is an important and evolving subject of cancer research. There has been a surge of interest in marine bioresources, particularly algae, as well as cyanobacteria and their bioactive ingredients. Dried biomass products of Arthrospira and Chlorella have been categorized as “generally recognized as safe” (GRAS) by the US Food and Drug Administration (FDA). Of particular importance is an ingredient of Arthrospira: phycocyanin, a blue-red fluorescent, water-soluble and non-toxic biliprotein pigment. It is reported to be the main active ingredient of Arthrospira and was shown to have therapeutic properties, including anti-oxidant, anti-inflammatory, immune-modulatory and anti-cancer activities. In the present review, in vitro and in vivo data on the effects of phycocyanin on various tumor cells and on cells from healthy tissues are summarized. The existing knowledge of underlying molecular mechanisms, and strategies to improve the efficiency of potential phycocyanin-based anti-cancer therapies are discussed.

Genomic Testing in Patients with Metastatic Castration-resistant Prostate Cancer: A Pragmatic Guide for Clinicians

CONTEXT

Genomic testing is becoming increasingly important in patients with advanced prostate cancer (PC) and is being incorporated in clinical practice to guide treatment.

OBJECTIVE

To review the current understanding of genomic alterations and the status of genomic testing in patients with metastatic castration-resistant PC (mCRPC), and the potential use of genomic tests in clinical practice.

EVIDENCE ACQUISITION

We reviewed recent publications (past 15 yr) from PubMed, proceedings of scientific conferences, and published guidelines. Reports on mCRPC in the following areas were selected: development, testing, and validation of techniques for identifying genomic alterations; molecular characterization; and trials of genetically targeted therapies.

EVIDENCE SYNTHESIS

mCRPC tumors harbor molecular alterations that are possible targets for treatment, and a number of therapies are in development to exploit these alterations (eg, PD-1 inhibitors, PARP inhibitors, tyrosine kinase inhibitors). Next-generation sequencing of DNA from tumor tissue can identify somatic alterations that would not be identified by germline testing. Work is ongoing to evaluate the use of less invasive somatic testing methods (eg, sequencing of cell-free circulating tumor DNA). Current international guidelines recommend germline and/or somatic testing for men with advanced and/or high-risk PC regardless of family history to identify those with homologous recombination repair gene mutations or mismatch repair defects/microsatellite instability who may be eligible for treatment with a PARP inhibitor or pembrolizumab, respectively.

CONCLUSIONS

Genomic testing for mCRPC may provide information on prognostic, predictive, and resistance biomarkers. Although the incorporation of testing into clinical practice remains challenging, routine genomic testing of men with advanced PC is recommended to guide management and treatment decisions.

PATIENT SUMMARY

Similar to many cancers, prostate cancer is caused by defects in the cancer's DNA, which are called genetic or genomic defects. New treatments targeting these defects are approved for metastatic castration-resistant prostate cancer. Specific new tests are under development to detect these potentially treatable genetic defects.