CDK12-Altered Prostate Cancer: Clinical Features and Therapeutic Outcomes to Standard Systemic Therapies, Poly (ADP-Ribose) Polymerase Inhibitors, and PD-1 Inhibitors

DNA Damage Repair Pathways in Prostate Cancer: A Narrative Review of Molecular Mechanisms, Emerging Biomarkers and Therapeutic Targets in Precision Oncology

Prostate cancer (PCa) has a distinct molecular signature, including characteristic chromosomal translocations, gene deletions and defective DNA damage repair mechanisms. One crucial pathway involved is homologous recombination deficiency (HRD) and it is found in almost 20% of metastatic castrate-resistant PCa (mCRPC). Inherited/germline mutations are associated with a hereditary predisposition to early PCa development and aggressive behavior. BRCA2, ATM and CHECK2 are the most frequently HRD-mutated genes. BRCA2-mutated tumors have unfavorable clinical and pathological characteristics, such as intraductal carcinoma. PARP inhibitors, due to the induction of synthetic lethality, have been therapeutically approved for mCRPC with HRD alterations. Mutations are detected in metastatic tissue, while a liquid biopsy is utilized during follow-up, recognizing acquired resistance mechanisms. The mismatch repair (MMR) pathway is another DNA repair mechanism implicated in carcinogenesis, although only 5% of metastatic PCa is affected. It is associated with aggressive disease. PD-1 inhibitors have been used in MMR-deficient tumors; thus, the MMR status should be tested in all metastatic PCa cases. A surrogate marker of defective DNA repair mechanisms is the tumor mutational burden. PDL-1 expression and intratumoral lymphocytes have ambivalent predictive value. Few experimental molecules have been so far proposed as potential biomarkers. Future research may further elucidate the role of DNA damage pathways in PCa, revealing new therapeutic targets and predictive biomarkers.

Recent Research Advances in Double-Strand Break and Mismatch Repair Defects in Prostate Cancer and Potential Clinical Applications

Prostate cancer remains a leading cause of cancer-related death in men worldwide. Recent research advances have emphasized the critical roles of mismatch repair (MMR) and double-strand break (DSB) in prostate cancer development and progression. Here, we provide a comprehensive review of the molecular mechanisms underlying DSB and MMR defects in prostate cancer, as well as their clinical implications. Furthermore, we discuss the promising therapeutic potential of immune checkpoint inhibitors and PARP inhibitors in targeting these defects, particularly in the context of personalized medicine and further perspectives. Recent clinical trials have demonstrated the efficacy of these novel treatments, including Food and Drugs Association (FDA) drug approvals, offering hope for improved patient outcomes. Overall, this review emphasizes the importance of understanding the interplay between MMR and DSB defects in prostate cancer to develop innovative and effective therapeutic strategies for patients.

Management of patients with advanced prostate cancer-metastatic and/or castration-resistant prostate cancer: Report of the Advanced Prostate Cancer Consensus Conference (APCCC) 2022

BACKGROUND

Innovations in imaging and molecular characterisation together with novel treatment options have improved outcomes in advanced prostate cancer. However, we still lack high-level evidence in many areas relevant to making management decisions in daily clinical practise. The 2022 Advanced Prostate Cancer Consensus Conference (APCCC 2022) addressed some questions in these areas to supplement guidelines that mostly are based on level 1 evidence.

OBJECTIVE

To present the voting results of the APCCC 2022.

DESIGN, SETTING, AND PARTICIPANTS

The experts voted on controversial questions where high-level evidence is mostly lacking: locally advanced prostate cancer; biochemical recurrence after local treatment; metastatic hormone-sensitive, non-metastatic, and metastatic castration-resistant prostate cancer; oligometastatic prostate cancer; and managing side effects of hormonal therapy. A panel of 105 international prostate cancer experts voted on the consensus questions.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The panel voted on 198 pre-defined questions, which were developed by 117 voting and non-voting panel members prior to the conference following a modified Delphi process. A total of 116 questions on metastatic and/or castration-resistant prostate cancer are discussed in this manuscript. In 2022, the voting was done by a web-based survey because of COVID-19 restrictions.

RESULTS AND LIMITATIONS

The voting reflects the expert opinion of these panellists and did not incorporate a standard literature review or formal meta-analysis. The answer options for the consensus questions received varying degrees of support from panellists, as reflected in this article and the detailed voting results are reported in the supplementary material. We report here on topics in metastatic, hormone-sensitive prostate cancer (mHSPC), non-metastatic, castration-resistant prostate cancer (nmCRPC), metastatic castration-resistant prostate cancer (mCRPC), and oligometastatic and oligoprogressive prostate cancer.

CONCLUSIONS

These voting results in four specific areas from a panel of experts in advanced prostate cancer can help clinicians and patients navigate controversial areas of management for which high-level evidence is scant or conflicting and can help research funders and policy makers identify information gaps and consider what areas to explore further. However, diagnostic and treatment decisions always have to be individualised based on patient characteristics, including the extent and location of disease, prior treatment(s), co-morbidities, patient preferences, and treatment recommendations and should also incorporate current and emerging clinical evidence and logistic and economic factors. Enrolment in clinical trials is strongly encouraged. Importantly, APCCC 2022 once again identified important gaps where there is non-consensus and that merit evaluation in specifically designed trials.

PATIENT SUMMARY

The Advanced Prostate Cancer Consensus Conference (APCCC) provides a forum to discuss and debate current diagnostic and treatment options for patients with advanced prostate cancer. The conference aims to share the knowledge of international experts in prostate cancer with healthcare providers worldwide. At each APCCC, an expert panel votes on pre-defined questions that target the most clinically relevant areas of advanced prostate cancer treatment for which there are gaps in knowledge. The results of the voting provide a practical guide to help clinicians discuss therapeutic options with patients and their relatives as part of shared and multidisciplinary decision-making. This report focuses on the advanced setting, covering metastatic hormone-sensitive prostate cancer and both non-metastatic and metastatic castration-resistant prostate cancer.

TWITTER SUMMARY

Report of the results of APCCC 2022 for the following topics: mHSPC, nmCRPC, mCRPC, and oligometastatic prostate cancer.

TAKE-HOME MESSAGE

At APCCC 2022, clinically important questions in the management of advanced prostate cancer management were identified and discussed, and experts voted on pre-defined consensus questions. The report of the results for metastatic and/or castration-resistant prostate cancer is summarised here.

Comparison of circulating tumor DNA between African American and Caucasian patients with metastatic castrate-resistant prostate cancer post-abiraterone and/or enzalutamide

BACKGROUND

African American men are much more likely than Caucasian men to be diagnosed with and to die of prostate cancer. Genetic differences likely play a role. The cBioPortal database reveals that African American men with prostate cancer have higher rates of CDK12 somatic mutations compared to Caucasian men. However, this does not account for prior prostate cancer treatments, which are particularly important in the castrate-resistant setting. We aimed to compare somatic mutations based on circulating tumor DNA (ctDNA) in metastatic castration-resistant prostate cancer (mCRPC) between African American and Caucasian men after exposure to abiraterone and/or enzalutamide.

METHODS

This single-institution retrospective study characterizes the somatic mutations detected on ctDNA for African American and Caucasian men with mCRPC who had progressed after abiraterone and/or enzalutamide from 2015 through 2022. We evaluated the gene mutations and types of mutations in this mCRPC cohort.

RESULTS

There were 50 African American and 200 Caucasian men with CRPC with available ctDNA data. African American men were younger at the time of diagnosis (p = 0.008) and development of castration resistance (p = 0.006). African American men were more likely than Caucasian men to have pathogenic/likely pathogenic (P/LP) mutations in CDK12 (12% vs. 1.5%; p = 0.003) and copy number amplifications and P/LP mutations in KIT (8.0% vs. 1.5%; p = 0.031). African American men were also significantly more likely to have frameshift mutations (28% vs. 14%; p = 0.035).

CONCLUSIONS

Compared to Caucasian men, African American men with mCRPC after exposure to abiraterone and/or enzalutamide had a higher incidence of somatic CDK12 P/LP mutations and KIT amplifications and P/LP mutations based on ctDNA. African American men also had more frameshift mutations. We hypothesize that these findings have potential implications for tumor immunogenicity.

Black Patients with Metastatic Castrate-Resistant Prostate Cancer Have a Shorter Time Interval Between PSA and Clinical Progression on Novel Hormonal Therapies plus Avelumab

BACKGROUND

Black men are at higher risk for prostate cancer death. Previous studies showed a benefit of different therapies, including immune-based therapy, for Black men with metastatic prostate cancer. We sought to explore the efficacy of the PD-L1 inhibitor avelumab in Black men with metastatic castrate-resistant prostate cancer (mCRPC) progressing after abiraterone or enzalutamide.

METHODS

This pilot phase II study enrolled self-identified Black patients who developed mCRPC on next-generation hormonal therapies (NHTs) abiraterone acetate or enzalutamide (NCT03770455). Enrolled patients received avelumab 10mg/kg IV every 2 weeks while remaining on the same NHTs. The primary endpoint of our study was ≥ 50% reduction in prostate specific antigen (PSA) at ≥8 weeks.

RESULTS

A total of eight patients were enrolled. The median duration on NHTs prior to enrollment was 364 days (95% CI, 260.9-467.1). The median time to initiate avelumab was 8 days (3-14). With a median follow-up of 196 days, no patients achieved the primary endpoint. The median time to PSA progression was 35 days (95 CI%, 0-94.8) and the median time to radiographic and/or clinical progression was 44 days (95 CI%, 0-118.5). The study was closed prematurely due to safety concerns related to the rapid clinical progression observed in the patients enrolled on study.

CONCLUSION

In conclusion, the addition of avelumab to NHT did not demonstrate clinical activity in Black men with new mCRPC. The unexpected short interval between PSA and radiographic and/or clinical progression observed in this study has potential clinical implications.ClinicalTrials.gov Identifier: NCT03770455 (IND number 139559).

A review of treatments targeting DNA-repair gene defects in metastatic castration resistant prostate cancer

Prostate cancer is the most common cancer in men. About 6% of those diagnosed will develop metastatic disease. Unfortunately, metastatic prostate cancer is fatal. Prostate cancer can be castration sensitive or castration resistant. Many treatments have been shown to improve progression free survival and overall survival in metastatic castration resistant prostate cancer (mCRPC). In recent years, studies have been exploring targeting mutations in the DNA Damage Repair (DDR) response that may amplify oncogenes. In this paper, we aim to discuss DDR, new approved targeted therapies, and the most recent clinical trials in the setting of metastatic CRPC.

Genetic profiling of hormone-sensitive and castration-resistant prostate cancers and identification of genetic mutations prone to castration-resistant prostate cancer

BACKGROUND

Genetic profiling of patients with prostate cancer could potentially identify mutations prone to castration-resistant prostate cancer (CRPC). Here, we aimed to identify the differences in genetic profiles of patients with hormone-sensitive prostate cancer (HSPC) and CRPC and stratify HSPC patients to identify mutations associated with CRPC progression.

METHODS

A total of 103 samples were collected, including 62 DNA samples from the tumor tissues of 59 HSPC patients and 41 cell-free DNA (cfDNA) samples from prostate cancer patients at different cancer stages. Targeted sequence was conducted on both the tissue DNA and cfDNA. The associations between mutations and clinical outcomes (CRPC-free time) were analyzed using χ2 test, logistic regression analysis, Kaplan-Meier analysis, and Cox regression analysis.

RESULTS

By comparing to that of cfDNA sequencing, the results from DNA sequencing of 1-needle (80%) and mixed 12-needle (77.8%) biopsies are highly comparable. FOXA1 (30.5%), CDK12 (23.7%), and TP53 (22.0%) were the top 3 most frequently mutated genes in HSPC patients; 50.8% (30/59) and 44.1% (26/59) HSPC patients had mutations in DDR and HRR pathway, respectively. Mutations in AR and APC as well as the members involved in the regulation of stem cell pluripotency and EMT pathway were often observed in CRPC samples. We established a panel of four genetic mutations (MSH2, CDK12, TP53, and RB1) to predict the risk of CRPC early progression with concordance index = 0.609 and the area under curve of the ROC curve as 0.838.

CONCLUSIONS

In this study, we demonstrated that the cfDNA can be used in genetic profiling in prostate cancer and our newly established panel is capable of predicting which mHSPC patient has a high risk of early CRPC progression.

Prognostic value of genomic mutations in metastatic prostate cancer

Metastatic prostate cancer (mPC) has a poor prognosis, and new treatment strategies are currently being offered for patients in clinical practice, but mPC is still incurable. A considerable proportion of patients with mPC harbor homologous recombination repair (HRR) mutations, which may be more sensitive to poly (ADP-ribose) polymerase inhibitors (PARPis). We retrospectively included genomic and clinical data from 147 patients with mPC from a single clinical center, with a total of 102 circulating tumor DNA (ctDNA) samples and 60 tissue samples. The frequency of genomic mutations was analyzed and compared with that in Western cohorts. Cox analysis was used to assess progression-free survival (PFS) and prognostic factors related to prostate-specific antigen (PSA) after standard systemic therapy for mPC. The most frequently mutated gene in the HRR pathway was CDK12 (18.3%), followed by ATM (13.7%) and BRCA2 (13.0%). The remaining common ones were TP53 (31.3%), PTEN (12.2%), and PIK3CA (11.5%). The frequency of BRCA2 mutation was close to that of the SU2C-PCF cohort (13.3%), but the frequency of CDK12, ATM, and PIK3CA mutations was significantly higher than that in the SU2C-PCF cohort: 4.7%, 7.3%, and 5.3%, respectively. CDK12 mutation were less responsive to androgen receptor signaling inhibitors (ARSIs), docetaxel, and PARPi. BRCA2 mutation helps predict PARPi efficacy. Additionally, androgen receptor (AR)-amplified patients do not respond well to ARSIs, and PTEN mutation are associated with poorer docetaxel response. These findings support the genetic profiling of patients with mPC after diagnosis to guide treatment stratification to customize personalized treatment.

Prognostic and clinicopathological value of CDK12 mutation in prostate cancer: a meta-analysis

BACKGROUND

Cyclin-dependent kinase 12 (CDK12) mutation has been shown to be associated with the prognosis and clinicopathological characteristics of various tumors. The aim of this meta-analysis was to investigate the role of mutations in prostate cancer (PCa).

RESEARCH DESIGN AND METHODS

PubMed/Medline, EMBASE, Cochrane Library, and Web of Science database were searched for relevant articles. Meta-analysis was performed by using RevMan5.3 software, and the quality of the included literature was evaluated according to the Newcastle-Ottawa scale (NOS).

RESULTS

A total of 13 studies comprising 5182 participants were enrolled in this meta-analysis. The frequency of CDK12 mutation in PCa was 7.26%. CDK12 mutation was significantly correlated with poor OS/PFS and had a shorter time to progress to CRPC. CDK12 mutant was associated with high-grade Gleason scores, while no relationships were found among CDK12 mutant, age, and the PSA level at diagnosis.

CONCLUSION

This meta-analysis indicates that patients with CDK12 mutation have poor prognosis in PCa. CDK12 may be used as a biomarker for molecular subtype and a potential therapeutic target of PCa.

Transcription-associated cyclin-dependent kinase 12 (CDK12) as a potential target for cancer therapy

Cyclin-dependent kinase 12 (CDK12), a transcription-related cyclin dependent kinase (CDK), plays a momentous part in multitudinous biological functions, such as replication, transcription initiation to elongation and termination, precursor mRNA (pre-mRNA) splicing, intron polyadenylation (IPA), and translation. CDK12 can act as a tumour suppressor or oncogene in disparate cellular environments, and its dysregulation likely provokes tumorigenesis. A comprehensive understanding of CDK12 will tremendously facilitate the exploitation of novel tactics for the treatment and precaution of cancer. Currently, CDK12 inhibitors are nonspecific and nonselective, which profoundly hinders the pharmacological target validation and drug exploitation process. Herein, we summarize the newly comprehension of the biological functions of CDK12 with a focus on recently emerged advancements of CDK12-associated therapeutic approaches in cancers.

Molecular Genetics of Prostate Cancer and Role of Genomic Testing

Prostate cancer (PCa) is characterized by profound genomic heterogeneity. Recent advances in personalized treatment entail an increasing need of genomic profiling. For localized PCa, gene expression assays can support clinical decisions regarding active surveillance and adjuvant treatment. In metastatic PCa, homologous recombination deficiency, microsatellite instability-high (MSI-H), and CDK12 deficiency constitute main actionable alterations. Alterations in DNA repair genes confer variable sensitivities to poly(ADP-ribose)polymerase inhibitors, and the use of genomic instability assays as predictive biomarker is still incipient. MSI can be assessed by immunohistochemistry To date there is a lack of consensus as to testing standards.

Delineation of molecular characteristics in pediatric PFA ependymoma involving rare osseous and pulmonary metastases: A case report and literature review

Ependymoma is the third most common pediatric primary brain tumor, with its most aggressive subtype being posterior fossa group A (PFA). Extraneural metastasis of pediatric PFA ependymoma is rare. Herein, we present a case of a 9-year-old girl with PFA ependymoma characterized by a lack of trimethylation of histone H3 at lysine 27 and elevated chromosome X open reading frame 67 expression. Despite multiple surgeries and radiotherapies, the patient had a rapid recurrence and developed osseous and pulmonary metastases, which may be attributed to the homozygous deletion of cyclin-dependent kinase (CDK) inhibitor 2A/B and CDK12 mutation. Importantly, the CDK12 mutation observed in the patient may be indicative of the need for further work-up to consider chemotherapy rather than administering poly (adenosine diphosphate-ribose) polymerase inhibitors. Taken together, this is the first report of pediatric PFA ependymoma with extraneural metastases, wherein we clarified the diagnostic procedures of this newly identified PFA ependymoma and provided new cues to study the invasiveness of this disease and treatment selection for such patients.

Characteristics of homologous recombination repair pathway genes mutation in ovarian cancers

Background

Few studies have investigated the characteristics of non-BRCA homologous recombination repair (HRR) pathway somatic mutations, and the impact of these mutations on efficacy of treatment in ovarian cancer patients is not clear. Therefore, we conducted this study to analyze the frequency and spectrum of somatic mutations in HRR pathway genes in patients with ovarian cancer and to examine the relationships between somatic mutations in HRR pathway genes and their effects on the efficacy of platinum-based chemotherapy.

Methods

We performed targeted sequencing of 688 genes related to the occurrence, development, treatment, and prognosis of solid tumors. Somatic mutations were identified by paired analysis of tumor tissue and germline DNA in blood cells.

Results

A total of 38 patients with ovarian cancer were included in the study, and 35 (92.1%) patients were diagnosed with high-grade serous carcinoma. All patients exhibited somatic mutations in the tumor tissue samples. The commonly mutated genes were TP53 (73.7%), BRCA2 (55.3%), NF1 (52.6%), BRCA1 (47.4%), and CDH1 (47.4%). Overall, 71.1% of the patients exhibited mutation in at least one HRR pathway gene. The most frequently altered HRR genes were BRCA2 (55.3%), followed by BRCA1 (47.4%), ATM (44.7%), BARD1 (42.1%), and CHEK1 (36.8%). The median progression-free survival (PFS) in patients with HRR pathway mutation was 36.0 months compared with 13.6 months in patients with no HRR pathway mutation (hazard ratio [HR], 0.25; 95% confidence interval [CI], 0.08-0.77; p = 0.016). Patients harboring BRCA1/2 and/or CDK12 mutations displayed a longer PFS (median, 36.0 months) compared with patients with no BRCA1/2 or CDK12 mutation (median, 13.6 months; HR, 0.21; 95% CI, 0.07-0.61; p = 0.004). In multivariate analysis Cox proportional hazards models, after adjustment for tumor stage at diagnosis and histology of initial diagnosis, patients with HRR pathway mutation had a longer PFS than patients with HRR wild-type genes (p = 0.006).

Conclusions

HRR pathway somatic mutations are common in Chinese patients with ovarian cancer. HRR pathway somatic mutations were associated with improved sensitivity to platinum-based chemotherapy. Large-scale prospective studies are needed to verify our findings.

Prostate cancer treatment - China's perspective

Prostate cancer (PCa) incidence and mortality have rapidly increased in China. Notably, unique epidemiological characteristics of PCa are found in the Chinese PCa population, including a low but rising incidence and an inferior but improving disease prognosis. Consequently, the current treatment landscape of PCa in China demonstrates distinct features. Establishing a more thorough understanding of the characteristics of Chinese patients may help provide novel insights into potential treatment strategies for PCa patients. Herein, we review the epidemiological status and differences in treatment modalities of Chinese PCa patients. In addition, we discuss the underlying socioeconomic and biological factors that contribute to such diversity and further propose directions for future efforts in optimizing the PCa treatment in China.

Applications for open access normalized synthesis in metastatic prostate cancer trials

Recent metastatic castration-resistant prostate cancer (mCRPC) clinical trials have integrated homologous recombination and DNA repair deficiency (HRD/DRD) biomarkers into eligibility criteria and secondary objectives. These trials led to the approval of some PARP inhibitors for mCRPC with HRD/DRD indications. Unfortunately, biomarker-trial outcome data is only discovered by reviewing publications, a process that is error-prone, time-consuming, and laborious. While prostate cancer researchers have written systematic evidence reviews (SERs) on this topic, given the time involved from the last search to publication, an SER is often outdated even before publication. The difficulty in reusing previous review data has resulted in multiple reviews of the same trials. Thus, it will be useful to create a normalized evidence base from recently published/presented biomarker-trial outcome data that one can quickly update. We present a new approach to semi-automating normalized, open-access data tables from published clinical trials of metastatic prostate cancer using a data curation and SER platform. Clinicaltrials.gov and Pubmed.gov were used to collect mCRPC clinical trial publications with HRD/DRD biomarkers. We extracted data from 13 publications covering ten trials that started before 22nd Apr 2021. We extracted 585 hazard ratios, response rates, duration metrics, and 543 adverse events. Across 334 patients, we also extracted 8,180 patient-level survival and biomarker values. Data tables were populated with survival metrics, raw patient data, eligibility criteria, adverse events, and timelines. A repeated strong association between HRD and improved PARP inhibitor response was observed. Several use cases for the extracted data are demonstrated via analyses of trial methods, comparison of treatment hazard ratios, and association of treatments with adverse events. Machine learning models are also built on combined and normalized patient data to demonstrate automated discovery of therapy/biomarker relationships. Overall, we demonstrate the value of systematically extracted and normalized data. We have also made our code open-source with simple instructions on updating the analyses as new data becomes available, which anyone can use even with limited programming knowledge. Finally, while we present a novel method of SER for mCRPC trials, one can also implement such semi-automated methods in other clinical trial domains to advance precision medicine.

Boosting the Immune Response—Combining Local and Immune Therapy for Prostate Cancer Treatment

Due to its slow progression and susceptibility to radical forms of treatment, low-grade PC is associated with high overall survival (OS). With the clinical progression of PC, the therapy is becoming more complex. The immunosuppressive tumor microenvironment (TME) makes PC a difficult target for most immunotherapeutics. Its general immune resistance is established by e.g., immune evasion through Treg cells, synthesis of immunosuppressive mediators, and the defective expression of surface neoantigens. The success of sipuleucel-T in clinical trials initiated several other clinical studies that specifically target the immune escape of tumors and eliminate the immunosuppressive properties of the TME. In the settings of PC treatment, this can be commonly achieved with radiation therapy (RT). In addition, focal therapies usually applied for localized PC, such as high-intensity focused ultrasound (HIFU) therapy, cryotherapy, photodynamic therapy (PDT), and irreversible electroporation (IRE) were shown to boost the anti-cancer response. Nevertheless, the present guidelines restrict their application to the context of a clinical trial or a prospective cohort study. This review explains how RT and focal therapies enhance the immune response. We also provide data supporting the combination of RT and focal treatments with immune therapies.

Chronological Liquid Biopsy Reveals the Impact of Platinum-Based Chemotherapy on a Prostate Cancer Patient’s CDK12 Mutation: A Case Report

CDK12 (Cyclin-Dependent Kinase 12)-mutated prostate cancer patients often respond badly to current therapies. Immunotherapy and platinum-based chemotherapy are recommended based on the molecular features of CDK12-mutated tumors, but the reported patient outcomes are still unsatisfying. Here we report a prostate cancer patient with CDK12 somatic mutation who received multiple therapy options, including platinum-based chemotherapy and immunotherapy. His sequential circulating tumor DNA (ctDNA) -based liquid biopsy tests showed that his original CDK12 mutation fell undetectable twice. This phenomenon was observed only when he was responding well to platinum-based chemotherapy. His responses to immunotherapy were not satisfying. This case indicates that platinum-based chemotherapy can be a good option for treating patients with CDK12 mutation. More importantly, dynamic ctDNA-based liquid biopsies to monitor patients’ CDK12 mutation status are critical in evaluating patients’ response and tolerance during platinum-based chemotherapy, therefore may lead to a better overall prognosis. In conclusion, CDK12-mutated prostate cancer patients are likely to benefit from platinum-based chemotherapy, especially with the help of dynamic ctDNA-based liquid biopsies to monitor their CDK12 mutation status.

Prostate cancer immunotherapy: a review of recent advancements with novel treatment methods and efficacy

Immunotherapy remains to be an appealing treatment option for prostate cancer with some documented promise. Prostate cancer is traditionally considered as an immunologically "cold" tumor with low tumor mutation burden, low expression of PD-L1, sparse T-cell infiltration, and a immunosuppressive tumor microenvironment (TME). Sipuleucel-T (Provenge) is the first FDA approved immunotherapeutic agent for the treatment of asymptomatic or minimally symptomatic metastatic castrate resistant prostate cancer (mCRPC); demonstrating a benefit in overall survival. However various clinical trials by immune checkpoint inhibitors (ICIs) and their combinations with other drugs have shown limited responses in mCRPC. Up to now, only a small subset of patients with mismatch repair deficiency/microsatellite instability high and CDK12 mutations can clinically benefit from ICIs and/or their combinations with other agents, such as DNA damage agents. The existence of a large heterogeneity in genomic alterations and a complex TME in prostate cancer suggests the need for identifying new immunotherapeutic targets. As well as designing personalized immunotherapy strategies based on patient-specific molecular signatures. There is also a need to adjust strategies to overcome histologic barriers such as tissue hypoxia and dense stroma. The racial differences of immunological responses between men of diverse ethnicities also merit further investigation to improve the efficacy of immunotherapy and better patient selection in prostate cancer.

Clinical implications of homologous recombination repair mutations in prostate cancer

Prostate cancer is a disease with significant interpatient genomics, with a proportion of patients presenting mutations in key homologous recombination repair (HRR) gene aberrations, particularly in late-stage disease. A better understanding of the genomic landscape of prostate cancer and the prognostic and predictive value of HRR mutations could lead to more precise care for prostate cancer patients. BRCA1/2 mutations are associated with a more aggressive disease course and higher risk of developing lethal prostate cancer, but also identify patients who could benefit from directed therapeutic strategies with PARP inhibitors. Other HRR mutations are also frequent but their prognostic and predictive value for prostate cancer patients is less clear. Moreover, a proportion of these mutations are associated with inherited germline defects, being relevant for the patients' risk of second malignancies but also to inform their relatives' risk of cancer through cascade testing. In this manuscript, we review current knowledge of the prognostic and predictive value for different HHR alterations across the different prostate cancer disease states. Additionally, we assess the challenges to implement genomic testing in clinical practice for prostate cancer patients.

Mismatch repair deficiency and clinical implications in prostate cancer

Despite recent therapeutic advances, castration-resistant prostate cancer (CRPC) remains a lethal disease and novel therapies are needed. Precision oncology provides an avenue for developing effective tailored approaches for treating malignancies based on a tumor's molecular profile. Indeed, the presence of mismatch repair deficiency (MMRd) has proven to be an important predictive biomarker for response to immune checkpoint blockade across multiple tumor types, including prostate cancer, and represents a major precision oncology success story. The mismatch repair (MMR) system is integral to maintaining genomic fidelity during cellular replication. Cancers with deficiencies in this system accumulate high numbers of mutations and express many neoantigens that may be recognized by the immune system. The checkpoint inhibitor pembrolizumab has recently been approved for all cancers that are MMR deficient, and several retrospective series have specifically shown that pembrolizumab is effective in MMRd prostate cancer. Although the prevalence of MMRd in CRPC is low (approximately 3%-5% of cases), this is an important subset of men that require a unique therapeutic approach. This review will focus on MMRd in prostate cancer, highlighting the clinical implications, role of immunotherapy, and areas of future research.

Multisite Radiotherapy Combined With Tislelizumab for Metastatic Castration-Resistant Prostate Cancer With Second-Line and Above Therapy Failure: Study Protocol for an Open-Label, Single-Arm, Phase Ib/II Study

Background

Tislelizumab combined with radiotherapy as a salvage treatment for patients with end-stage metastatic castration-resistant prostate cancer (mCRPC) is not reported. This study aimed to describe a protocol to evaluate the safety and efficacy of multisite radiotherapy combined with tislelizumab as a salvage therapy for mCRPC in patients who had at least one second-line treatment failure.

Methods

The study included patients with mCRPC who had at least one lesion suitable for radiotherapy and failed androgen deprivation therapy (ADT), followed by at least one novel second-line endocrine therapy. All patients received tislelizumab monotherapy induction therapy for two cycles, then combined with multisite radiotherapy for one cycle, followed by tislelizumab maintenance therapy, until either disease progressed or the patient developed unacceptable toxicity. Radiation methods and lesions were individually selected according to the specified protocol. Primary endpoints included safety and objective response rate. Secondary endpoints included prostate-specific antigen (PSA) response rate, disease control rate, overall survival, radiographic progression-free survival (rPFS), and biochemical progression-free survival (bPFS). Furthermore, the exploratory endpoints included the identification of the predictive biomarkers and exploration of the correlation between biomarkers and the tumor response to the combined regimen.

Discussion

This study included three treatment stages to evaluate the efficacy of immunotherapy and the combination of immunotherapy and radiotherapy for patients with mCRPC who have had at least second-line treatment failure. Additionally, radiation-related and immune-related early and late toxicities were determined, respectively. Furthermore, the study also aimed to identify the predictive biomarkers associated with immunotherapy for treating mCRPC.

Trial Registration

https://www.chictr.org.cn/showproj.aspx?proj=126359, identifier ChiCTR2100046212.

Identification of RPL15 60S Ribosomal Protein as a Novel Topotecan Target Protein That Correlates with DAMP Secretion and Antitumor Immune Activation

Damage-associated molecular patterns (DAMPs) contribute to antitumor immunity during cancer chemotherapy. We previously demonstrated that topotecan (TPT), a topoisomerase I inhibitor, induces DAMP secretion from cancer cells, which activates STING-mediated antitumor immune responses. However, how TPT induces DAMP secretion in cancer cells is yet to be elucidated. Here, we identified RPL15, a 60S ribosomal protein, as a novel TPT target and showed that TPT inhibited preribosomal subunit formation via its binding to RPL15, resulting in the induction of DAMP-mediated antitumor immune activation independent of TOP1. TPT inhibits RPL15-RPL4 interactions and decreases RPL4 stability, which is recovered by CDK12 activity. RPL15 knockdown induced DAMP secretion and increased the CTL population but decreased the regulatory T cell population in a B16-F10 murine melanoma model, which sensitized B16-F10 tumors against PD-1 blockade. Our study identified a novel TPT target protein and showed that ribosomal stress is a trigger of DAMP secretion, which contributes to antitumor immunotherapy.

Management of Patients with Advanced Prostate Cancer: Report from the Advanced Prostate Cancer Consensus Conference 2021

BACKGROUND

Innovations in treatments, imaging, and molecular characterisation in advanced prostate cancer have improved outcomes, but various areas of management still lack high-level evidence to inform clinical practice. The 2021 Advanced Prostate Cancer Consensus Conference (APCCC) addressed some of these questions to supplement guidelines that are based on level 1 evidence.

OBJECTIVE

To present the voting results from APCCC 2021.

DESIGN, SETTING, AND PARTICIPANTS

The experts identified three major areas of controversy related to management of advanced prostate cancer: newly diagnosed metastatic hormone-sensitive prostate cancer (mHSPC), the use of prostate-specific membrane antigen ligands in diagnostics and therapy, and molecular characterisation of tissue and blood. A panel of 86 international prostate cancer experts developed the programme and the consensus questions.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The panel voted publicly but anonymously on 107 pre-defined questions, which were developed by both voting and non-voting panel members prior to the conference following a modified Delphi process.

RESULTS AND LIMITATIONS

The voting reflected the opinions of panellists and did not incorporate a standard literature review or formal meta-analysis. The answer options for the consensus questions received varying degrees of support from panellists, as reflected in this article and the detailed voting results reported in the Supplementary material.

CONCLUSIONS

These voting results from a panel of experts in advanced prostate cancer can help clinicians and patients to navigate controversial areas of management for which high-level evidence is scant. However, diagnostic and treatment decisions should always be individualised according to patient characteristics, such as the extent and location of disease, prior treatment(s), comorbidities, patient preferences, and treatment recommendations, and should also incorporate current and emerging clinical evidence and logistic and economic constraints. Enrolment in clinical trials should be strongly encouraged. Importantly, APCCC 2021 once again identified salient questions that merit evaluation in specifically designed trials.

PATIENT SUMMARY

The Advanced Prostate Cancer Consensus Conference is a forum for discussing current diagnosis and treatment options for patients with advanced prostate cancer. An expert panel votes on predefined questions focused on the most clinically relevant areas for treatment of advanced prostate cancer for which there are gaps in knowledge. The voting results provide a practical guide to help clinicians in discussing treatment options with patients as part of shared decision-making.

Hepatoid prostatic carcinoma with adrenal metastasis and novel genetic alterations

Hepatoid carcinoma (HC) encompasses epithelial extrahepatic tumors exhibiting features of hepatocellular carcinoma (HCC) both by morphology and immunohistochemistry. Distinguishing metastatic HCC from HC may be challenging, particularly when limited material, such as a cytologic specimen, is available. HC from prostatic origin is unusual and has only rarely been characterized by cytology. Herein we present an 86-year-old male with history of castration-resistant prostate cancer developing a left adrenal gland nodule. Fine needle aspiration revealed a poorly differentiated malignant neoplasm diagnosed as metastatic hepatoid prostatic adenocarcinoma based on immunohistochemistry (positive for HepPar1, AFP, NKX3.1, PSMA, and Racemase; and negative for CK7, CK20, cytokeratin 34betaE12, p63, and Arg-1). Because prostatic carcinoma with hepatoid features is rare, and the patient had failed standard therapy, next generation sequencing was performed in an attempt to identify druggable molecular targets. Well-known prostate carcinoma-related alterations were found in three genes (CDK12, AR, and SPOP). In addition, three variants of uncertain significance (DDR2 R128C, SRC P428L, and HNRNPU K574Sfs*32) were identified, which to the best of our knowledge have not been previously reported. Our results support the power of an immunohistochemistry panel including Arg-1 and HepPar1 when HC is suspected, and highlight the value of cytology for comprehensive diagnostic evaluation.

Identification of Metabolism-Related Gene-Based Subgroup in Prostate Cancer

Prostate cancer is still the main male health problem in the world. The role of metabolism in the occurrence and development of prostate cancer is becoming more and more obvious, but it is not clear. Here we firstly identified a metabolism-related gene-based subgroup in prostate cancer. We used metabolism-related genes to divide prostate cancer patients from The Cancer Genome Atlas into different clinical benefit populations, which was verified in the International Cancer Genome Consortium. After that, we analyzed the metabolic and immunological mechanisms of clinical beneficiaries from the aspects of functional analysis of differentially expressed genes, gene set variation analysis, tumor purity, tumor microenvironment, copy number variations, single-nucleotide polymorphism, and tumor-specific neoantigens. We identified 56 significant genes for non-negative matrix factorization after survival-related univariate regression analysis and identified three subgroups. Patients in subgroup 2 had better overall survival, disease-free interval, progression-free interval, and disease-specific survival. Functional analysis indicated that differentially expressed genes in subgroup 2 were enriched in the xenobiotic metabolic process and regulation of cell development. Moreover, the metabolism and tumor purity of subgroup 2 were higher than those of subgroup 1 and subgroup 3, whereas the composition of immune cells of subgroup 2 was lower than that of subgroup 1 and subgroup 3. The expression of major immune genes, such as CCL2, CD274, CD276, CD4, CTLA4, CXCR4, IL1A, IL6, LAG3, TGFB1, TNFRSF4, TNFRSF9, and PDCD1LG2, in subgroup 2 was almost significantly lower than that in subgroup 1 and subgroup 3, which is consistent with the results of tumor purity analysis. Finally, we identified that subgroup 2 had lower copy number variations, single-nucleotide polymorphism, and neoantigen mutation. Our systematic study established a metabolism-related gene-based subgroup to predict outcomes of prostate cancer patients, which may contribute to individual prevention and treatment.

Molecular classification of hormone-sensitive and castration-resistant prostate cancer, using nonnegative matrix factorization molecular subtyping of primary and metastatic specimens

BACKGROUND

Despite the rapidly evolving therapeutic landscape, immunotherapy has demonstrated limited activity in prostate cancer. A greater understanding of the molecular landscape, particularly the expression of immune-related pathways, will inform future immunotherapeutic strategies. Consensus nonnegative matrix factorization (cNMF) is a novel model of molecular classification analyzing gene expression data, focusing on biological interpretation of metagenes and selecting meaningful clusters.

OBJECTIVE

We aimed to identify molecular subtypes of prostate cancer using cNMF and correlate these with existing biomarkers to inform future immunotherapeutic strategies.

METHODS

A cohort of archival tumor specimens from hormone-sensitive and castration-resistant disease was studied. Whole transcriptomic profiles were generated using TruSeq RNA Access technology and subjected to cNMF. Comprehensive genomic profiling was performed with the FoundationOne assay. NMF subtypes were characterized by gene expression pathways, genomic alterations and correlated with clinical data, then applied to The Cancer Genome Atlas data set.

RESULTS

We studied 164 specimens, including 52 castration-resistant and 13 paired primary/metastatic specimens. cNMF identified four distinct subtypes. NMF1 (19%) is enriched for immune-related and stromal-related pathways with transforming growth factor β (TGFβ) signature. NMF2 (36%) is associated with FOXO-mediated transcription signature and AKT signaling, NMF3 (26%) is enriched for ribosomal RNA processing, while NMF4 (19%) is enriched for cell cycle and DNA-repair pathways. The most common gene alterations included TMPRSS22 (42%), TP53 (23%), and DNA-repair genes (19%), occurring across all subtypes. NMF4 is significantly enriched for MYC and Wnt-signaling gene alterations. TMB, CD8 density, and PD-L1 expression were low overall. NMF1 and NMF4 were NMF2 was associated with superior overall survival.

CONCLUSIONS

Using cNMF, we identified four molecularly distinct subtypes which may inform treatment selection. NMF1 demonstrates the most inflammatory signature with asuppressive TGFβ signature, suggesting potential benefit with immunotherapy combination strategies targeting TGFβ and PD-(L)1. Prospective studies are required to evaluate the use of this novel model to molecularly stratify patients for optimal treatment selection.

PARP Inhibition, a New Therapeutic Avenue in Patients with Prostate Cancer

Up to 25% of patients with metastatic prostate cancer present with germline or somatic DNA damage repair alterations, some of which are associated with aggressive disease and poor outcomes. New data have brought poly(ADP-ribose) polymerase (PARP) inhibitors into sharp focus in the treatment of metastatic castrate-resistant prostate cancer (mCRPC). Olaparib improved survival after at least one new hormonal therapy (NHT) in a cohort of patients harboring BRCA1, BRCA2 or ATM mutations in the PROfound trial, while rucaparib, talazoparib and niraparib demonstrated compelling activity in phase II trials. While patients with prostate cancer and BRCA1 or BRCA2 mutations may derive greatest benefit of PARP inhibition, the magnitude of benefit seems much lower in the context of most other homologous recombination gene mutations. Several PARP inhibitors are currently developed in combination with conventional therapy, including chemotherapy, NHT, and alpha-particle emitters, at different disease stages. Herein, we review the rationale for PARP inhibition in patients with prostate cancer, discuss the impact of PARP inhibitors on outcomes, and explore underlying challenges for future developments.

Implications of DNA damage repair alterations for the management of prostate cancer

PURPOSE OF REVIEW

In this review, we summarize the prevalence of alterations in DNA damage repair (DDR) genes in prostate cancer, their clinical significance, the therapeutic strategies developed to take advantage of the impaired tumour ability to repair DNA and the diagnostic approaches available to identify patients likely to benefit from DDR-targeting agents.

RECENT FINDINGS

DDR alterations are more frequent in metastatic than in localized prostate cancer and some of them associate with aggressive disease whereas the significance of others remain unclear. The most appropriate management approach for DDR-defective prostate cancer patients is unknown. Clinical trials have demonstrated the efficacy of different poly-ADP ribose polymerase inhibitors (PARPi) to treat metastatic castration-resistant prostate cancer patients with BRCA1/2 alterations, although there may be other DDR alterations that sensitize patients to these drugs. Multiple strategies to target DDR defects are being investigated, including PARPi in combination, platinum-based chemotherapy and immunotherapy, both in earlier and late disease stages. Optimization of molecular testing is paramount for the implementation of precision oncology in prostate cancer.

SUMMARY

Certain DDR defects present in prostate cancer have prognostic and therapeutic implications whereas the significance of other DDR alterations is yet to be elucidated.

Association between pathogenic germline mutations in BRCA2 and ATM and tumor-infiltrating lymphocytes in primary prostate cancer

Pathogenic mutations in homologous recombination (HR) DNA repair genes may be associated with increased tumor mutational burden and numbers of tumor-infiltrating lymphocytes (TIL). Though HR-deficient prostate tumors have been anecdotally associated with improved responses to immunotherapy, it is unclear whether HR mutations or HR deficiency (HRD) scores predict for increased T-cell densities in this cancer. We evaluated 17 primary prostate tumors from patients with pathogenic germline BRCA2 mutations (gBRCA2) and 21 primary prostate tumors from patients with pathogenic germline ATM (gATM) mutations, which were compared to 19 control tumors lacking HR gene mutations, as well as the TCGA prostate cancer cohort. HRD score was estimated by targeted sequencing (gBRCA2 and gATM) or by SNP microarray (TCGA). Tumor-associated T-cell densities were assessed using validated automated digital image analysis of CD8 and FOXP3 immunostaining (gBRCA2 or gATM) or by methylCIBERSORT (TCGA). CD8 + and FOXP3 + T-cell densities were significantly correlated with each other in gBRCA2 and gATM cases. There was no significant difference between CD8 + or FOXP3 + TIL densities in gBRCA2 or gATM cases compared to controls. In the TCGA cohort, HRD score was associated with predicted CD8 + and FOXP3 + TILs. Associations were also seen for HRD score and TIL density among the germline-mutated cases. In contrast to mismatch repair-deficient primary prostate tumors, cancers from germline BRCA2 or ATM mutation carriers do not appear to be associated with elevated TIL density. However, measures of genomic scarring, such as HRD score, may be associated with increased tumor-infiltrating T-cells.

PARP Inhibitors as Monotherapy in Daily Practice for Advanced Prostate Cancers

Despite recent improvements in survival, metastatic castration-resistant prostate cancers (mCRPCs) remain lethal. Alterations in genes involved in the homologous recombination repair (HRR) pathway are associated with poor prognosis. Poly-ADP-ribose polymerase (PARP) inhibitors (PARPis) have demonstrated anti-tumoral effects by synthetic lethality in patients with mCRPCs harboring HRR gene alterations, in particular BRCA2. While both olaparib and rucaparib have obtained government approvals for use, the selection of eligible patients as well as the prescription of these treatments within the clinical urology community are challenging. This review proposes a brief review of the rationale and outcomes of PARPi treatment, then a pragmatic vision of PARPi use in terms of prescription and the selection of patients based on molecular screening, which can involve potential genetic counseling in the case of associated germinal alterations.

DNA-repair status should be assessed in treatment-emergent neuroendocrine prostate cancer before platinum-based therapy

OBJECTIVES

This study sought to provide contemporary data from a multi-institution with respect to DNA-repair genes (DRGs) status and its impact on effects of platinum-based chemotherapy in treatment-emergent neuroendocrine prostate cancer (t-NEPC), for which little data exist.

PATIENTS AND METHODS

All patients were retrospectively collected with eligible biopsied tissues for targeted next generation sequencing (NGS). The main outcomes were radiologic progression-free survival and overall survival according to Response Evaluation Criteria in Solid Tumors, version 1.1.

RESULTS

Among the 43 NEPC patients, 13/43 (30%) harbored homozygous deletions, deleterious mutations, or both in DRGs. Eleven patients (11/13, 85%) with DRGs aberrations had effective response, including 7 patients with BRCA1/2 defects and 2 with mismatch repair-deficient caused by MSH2 alterations. While significantly fewer responders (30%) were detected in patients without DRGs aberrations (odds ratio = 12.83, p = 0.003). Compared with patients without genomic DRGs aberrations, the hazard ratio (HR) for radiologic progression in those with DRGs defects was 0.42 (95% confidence interval [CI]: 0.19-0.93), and the HR for death was 0.65 (95% CI: 0.24-1.72). The most common adverse event of Grade 3 or 4 was anemia, as noted in 7 patients (16%).

CONCLUSION

The DRGs status is therapeutically meaningful in t-NEPC. Given the potential responses to platinum-based chemotherapy, our findings support the clinical use of NGS in t-NEPC patients to identify DRGs aberrations.

Avelumab Combined with Stereotactic Ablative Body Radiotherapy in Metastatic Castration-resistant Prostate Cancer: The Phase 2 ICE-PAC Clinical Trial

BACKGROUND

Immune checkpoint inhibitor monotherapy in metastatic castration-resistant prostate cancer (mCRPC) has produced modest results. High-dose radiotherapy may be synergistic with checkpoint inhibitors.

OBJECTIVE

To evaluate the efficacy and safety of the PD-L1 inhibitor avelumab with stereotactic ablative body radiotherapy (SABR) in mCRPC.

DESIGN, SETTING, AND PARTICIPANTS

From November 2017 to July 2019, this prospective phase 2 study enrolled 31 men with progressive mCRPC after at least one prior androgen receptor-directed therapy. Median follow-up was 18.0 mo.

INTERVENTION

Avelumab 10 mg/kg intravenously every 2 wk for 24 wk (12 cycles). A single fraction of SABR (20 Gy) was administered to one or two disease sites within 5 d before the first and second avelumab treatments.

OUTCOMES MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was the disease control rate (DCR), defined as a confirmed complete or partial response of any duration, or stable disease/non-complete response/non-progressive disease for ≥6 mo (Prostate Cancer Clinical Trials Working Group 3-modified Response Evaluation Criteria in Solid Tumours version 1.1). Secondary endpoints were the objective response rate (ORR), radiographic progression-free survival (rPFS), overall survival (OS), and safety. DCR and ORR were calculated using the Clopper-Pearson exact binomial method.

RESULTS AND LIMITATIONS

Thirty-one evaluable men were enrolled (median age 71 yr, 71% with ≥2 prior mCRPC therapy lines, 81% with >5 total metastases). The DCR was 48% (15/31; 95% confidence interval [CI] 30-67%) and ORR was 31% (five of 16; 95% CI 11-59%). The ORR in nonirradiated lesions was 33% (four of 12; 95% CI 10-65%). Median rPFS was 8.4 mo (95% CI 4.5-not reached [NR]) and median OS was 14.1 mo (95% CI 8.9-NR). Grade 3-4 treatment-related adverse events occurred in six patients (16%), with three (10%) requiring high-dose corticosteroid therapy. Plasma androgen receptor alterations were associated with lower DCR (22% vs 71%, p = 0.13; Fisher's exact test). Limitations include the small sample size and the absence of a control arm.

CONCLUSIONS

Avelumab with SABR demonstrated encouraging activity and acceptable toxicity in treatment-refractory mCRPC. This combination warrants further investigation.

PATIENT SUMMARY

In this study of men with advanced and heavily pretreated prostate cancer, combining stereotactic radiotherapy with avelumab immunotherapy was safe and resulted in nearly half of patients experiencing cancer control for 6 months or longer. Stereotactic radiotherapy may potentially improve the effectiveness of immunotherapy in prostate cancer.

Immune Checkpoint Inhibitors in Advanced Prostate Cancer: Current Data and Future Perspectives

Simple Summary

The treatment landscape of advanced prostate cancer (PCa) is constantly improving with the approval of many new therapeutic options. Immunotherapy in PCa has been investigated with disappointing results. This review aims to evaluate the potential role of immunotherapy in both castration-sensitive and castration-resistant PCa, discussing the immunobiology of PCa, the results of the current literature, and the ongoing clinical trials. Potential prognostic and/or predictive factors and future perspectives are also discussed.

Abstract

In the last 10 years, many new therapeutic options have been approved in advanced prostate cancer (PCa) patients, granting a more prolonged survival in patients with metastatic disease, which, nevertheless, remains incurable. The emphasis on immune checkpoint inhibitors (ICIs) has led to many trials in this setting, with disappointing results until now. Therefore, we discuss the immunobiology of PCa, presenting ongoing trials and the available clinical data, to understand if immunotherapy could represent a valid option in this disease, and which subset of patients may be more likely to benefit. Current evidence suggests that the tumor microenvironment needs a qualitative rather than quantitative evaluation, along with the genomic determinants of prostate tumor cells. The prognostic or predictive value of immunotherapy biomarkers, such as PD-L1, TMB, or dMMR/MSI-high, needs further evaluation in PCa. Monotherapy with immune checkpoint inhibitors (ICIs) has been modestly effective. In contrast, combined strategies with other standard treatments (hormonal agents, chemotherapy, PARP inhibitors, radium-223, and TKIs) have shown some results. Immunotherapy should be better investigated in biomarker-selected patients, particularly with specific pathway aberrations (e.g., AR-V7 variant, HRD, CDK12 inactivated tumors, MSI-high tumors). Lastly, we present new possible targets in PCa that could potentially modulate the tumor microenvironment and improve antitumor activity with ICIs.

Immunotherapy in Advanced Prostate Cancer-Light at the End of the Tunnel?

Immunotherapeutic treatment approaches are now an integral part of the treatment of many solid tumors. However, attempts to integrate immunotherapy into the treatment of prostate cancer have been disappointing so far. This is due to a highly immunosuppressive, "cold" tumor microenvironment, which is characterized, for example, by the absence of cytotoxic T cells, an increased number of myeloid-derived suppressor cells or regulatory T cells, a decreased number of tumor antigens, or a defect in antigen presentation. The consequence is a reduced efficacy of many established immunotherapeutic treatments such as checkpoint inhibitors. However, a growing understanding of the underlying mechanisms of tumor-immune system interactions raises hopes that immunotherapeutic strategies can be optimized in the future. The aim of this review is to provide an overview of the current status and future directions of immunotherapy development in prostate cancer. Background information on immune response and tumor microenvironment will help to better understand current therapeutic strategies under preclinical and clinical development.

Immunotherapy in Advanced Prostate Cancer: Current Knowledge and Future Directions

The advent of immunotherapy has revolutionized cancer treatment. Unfortunately, this has not been the case for metastatic castration-resistant prostate cancer (mCRPC), likely due to the heterogeneous and immune-suppressive microenvironment present in prostate cancer. The identification of molecular biomarkers that could predict response to immunotherapy represents one of the current challenges in this clinical scenario. The management of advanced castration-resistant prostate cancer is rapidly evolving and immunotherapy treatments, mostly consisting of immune checkpoint inhibitors combinations, BiTE® (bispecific T-cell engager) immune therapies, and chimeric antigen receptors (CAR) are in development with promising results. This review analyses the current evidence of immunotherapy treatments for mCRPC, evaluating past failures and promising approaches and discussing the directions for future research.

Castration-resistant prostate cancer patient presenting with whole genome doubling with CDK-12 mutation

Background

The use of whole-genome sequencing in clinical practice has revealed variable genomic characteristics across cancer types, one of which is whole-genome doubling (WGD), which describes the duplication of a complete set of chromosomes. Yet it is relatively rare in prostate cancer and no such case has ever been reported in Japanese patients.

Case presentation

A 54-year-old patient with prostatic adenocarcinoma with bone and lymph node metastases was started on androgen-deprivation therapy. As the prostate cancer turned castration-resistant, multimodal therapies including taxane- and platinum-based chemotherapy, androgen-receptor antagonist inhibitors, radiotherapy and radium-233 were introduced. Good controls of serum prostate-specific antigen (PSA) level and bone metastases were achieved for more than 13 years since after the initial treatment. During the treatment, a metastatic lymph node biopsy was performed to confirm the tumor histology, and spinal decompression surgery were performed for spinal compression due to lumber vertebral metastases. The immunohistochemical analysis identified PSA and androgen receptor positive tumor cells in both metastatic lesions, while no variable cancer cells were detected in the prostate on second biopsy. Whole-genome sequencing was performed on the biopsied metastatic lymph node in search for another possible treatment and it revealed that the tumor had WGD and CDK12 mutation. The WGD-positive tumor cells contained large and polymorphic nucleus, presumably reflecting on the ploidy abnormality of the chromosomes.

Conclusions

This report is the first case of a Japanese patient presenting with WGD, who survived more than 13 years with multimodal chemotherapies and radiotherapies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01178-z.

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.

What Do We Have to Know about PD-L1 Expression in Prostate Cancer? A Systematic Literature Review (Part 6): Correlation of PD-L1 Expression with the Status of Mismatch Repair System, BRCA, PTEN, and Other Genes

Pembrolizumab (anti-PD-1) is allowed in selected metastatic castration-resistant prostate cancer (PC) patients showing microsatellite instability/mismatch repair system deficiency (MSI-H/dMMR). BRCA1/2 loss-of-function is linked to hereditary PCs and homologous recombination DNA-repair system deficiency: poly-ADP-ribose-polymerase inhibitors can be administered to BRCA-mutated PC patients. Recently, docetaxel-refractory metastatic castration-resistant PC patients with BRCA1/2 or ATM somatic mutations had higher response rates to pembrolizumab. PTEN regulates cell cycle/proliferation/apoptosis through pathways including the AKT/mTOR, which upregulates PD-L1 expression in PC. Our systematic literature review (PRISMA guidelines) investigated the potential correlations between PD-L1 and MMR/MSI/BRCA/PTEN statuses in PC, discussing few other relevant genes. Excluding selection biases, 74/677 (11%) PCs showed dMMR/MSI; 8/67 (12%) of dMMR/MSI cases were PD-L1+. dMMR-PCs included ductal (3%) and acinar (14%) PCs (all cases tested for MSI were acinar-PCs). In total, 15/39 (39%) PCs harbored BRCA1/2 aberrations: limited data are available for PD-L1 expression in these patients. 13/137 (10%) PTEN- PCs were PD-L1+; 10/29 (35%) PD-L1+ PCs showed PTEN negativity. SPOP mutations may increase PD-L1 levels, while the potential correlation between PD-L1 and ERG expression in PC should be clarified. Further research should verify how the efficacy of PD-1 inhibitors in metastatic castration-resistant PCs is related to dMMR/MSI, DNA-damage repair genes defects, or PD-L1 expression.

OUP accepted manuscript

Background

The outcomes of metastatic hormone-sensitive prostate cancer (mHSPC) have significantly improved through treatment intensification, yet Black representation in those studies is suboptimal.

Methods

A multi-institutional, retrospective analysis of Black men with mHSPC was conducted, focusing on baseline demographics, treatment patterns, genomic profiles, clinical outcomes including prostate-specific antigen response, time to castrate-resistant prostate cancer (CRPC), and subsequent treatments.

Results

A total of 107 patients, median age 64 years, 62% with de novo metastases at diagnosis and 64% with high-volume disease, were included. Twenty-nine patients (27%) were treated with androgen deprivation therapy (ADT) with and without first generation anti-androgens, while 20%, 38% and 5% received chemotherapy, abiraterone, and enzalutamide, respectively. At time of data cut-off, 57 (54%) patients had developed CRPC, with a median time to CRPC of 25.4 months (95% CI 20.3-30.4). The median time to CRPC was 46.3 months (18.9-73.7) and 23.4 months (18.6-28.2) for patients who received ADT with or without first-generation anti-androgens and treatment intensification, respectively. The 2-year survival rate was 93.3%, and estimated median overall survival of was 74.9 months (95% CI, 68.7-81.0). Most patients (90%) underwent germline testing; the most frequent known alterations were found within the DNA repair group of genes. Somatic testing revealed pathogenic alterations of interest, notably TP53 (24%) and CDK12 (12%).

Conclusion

In our cohort, Black men with mHSPC presented with a high proportion of de novo metastases and high-volume disease. Treatment outcomes were very favorable with ADT-based regimens. The genomic landscape suggests different molecular profile relative to White patients with potential therapeutic implications.

Analysis of CDK12 alterations in a pan-cancer database

BACKGROUND

CDK12 inactivation leading to increased neoantigen burden has been hypothesized to sensitize tumors to immune checkpoint inhibition. Pan-cancer data regarding the frequency of CDK12 alterations are limited. We aimed to characterize CDK12 alterations across all cancer types through real-world clinical-grade sequencing.

METHODS

This was a single-center retrospective analysis of 4994 cancer patients who underwent tissue or blood genomic profiling, including CDK12 assessment, conducted as part of routine care from December 2012 to January 2020. Prevalence, clinical characteristics, and treatment outcomes of patients with tumors with pathogenic CDK12 alterations were described.

RESULTS

In all, 39 (0.78%, n = 39/4994) patients had pathogenic CDK12 alterations. Among CDK12-altered tumors, the most common organ site was prostate (n = 9, 23.1%) followed by colorectal (n = 5, 12.8%). Adenocarcinoma was the most common histology (n = 26, 66.7%). Median follow-up from time of diagnosis was 4.02 years. Median overall survival from time of metastasis was 4.43 years (95% CI: 3.11-5.74). Ten patients with CDK12-altered tumors received at least one immune checkpoint inhibitor-containing regimen. The majority of patients (n = 6/10, 60%) experienced an objective response. Progression-free survival for patients who had metastatic disease and received a checkpoint inhibitor-containing regimen was 1.16 years (95% CI: 0.32-2.00).

CONCLUSION

CDK12 alterations are rare events across hematologic and solid tumor malignancies. They represent a clinically distinct molecular cancer subtype which may have increased responsiveness to checkpoint inhibition. Prospective studies are warranted to investigate checkpoint inhibition in CDK12-altered tumors.

Biomarker-driven immunotherapy for precision medicine in prostate cancer

Although immunotherapy has recently revolutionized standard of care in different cancer types, prostate cancer has generally failed to show dramatic responses to immune checkpoint inhibitors. As in other tumors, the goal in prostate cancer is now to target treatments more precisely on patient's individual characteristics through precision medicine. Defects in mismatch repair, mutations in the exonuclease domain of the DNA polymerase epsilon (POLE), high tumor mutational burden and the presence of biallelic loss of CDK12 among others, are predictive biomarkers of response to immunotherapy. In the present review, we summarize the evolving landscape of immunotherapy in prostate cancer, including precision approaches and strategies to define classes of responsive patients and scale up resistance to immune checkpoint inhibitors.

Tissue- and Blood-derived Genomic Biomarkers for Metastatic Hormone-sensitive Prostate Cancer: A Systematic Review

CONTEXT

Multiple studies have reported on the genomic characteristics of metastatic hormone-sensitive prostate cancer (mHSPC). The impact of these findings on prognostication, treatment selection, and clinical trial design remains unclear.

OBJECTIVE

To summarise genomic alteration prevalences in liquid and/or tissue biopsies, infer their clinical implications, and compare genomic alteration frequencies across different disease states and clinical phenotypes.

EVIDENCE ACQUISITION

The PubMed and Web of Knowledge databases were systematically searched up to January 2021. Quality assessment was performed using the Joanna Briggs Institute Critical Appraisal tools.

EVIDENCE SYNTHESIS

In total, 11 studies encompassing 1682 mHSPC patients were included. High-volume disease was associated with more frequent alterations in TP53, DNA damage repair, and Wnt pathways. Tumours from patients with de novo mHSPC were enriched for alterations in TP53 and CDK12 compared with recurrent disease. Alterations in AR, TP53, cell cycle signalling, and MYC were associated with a poorer clinical outcome. A comparative analysis of gene alteration frequencies across disease states revealed a relative increase from localised to castration-resistant tumours, with noteworthy enrichment of CTNNB1 alterations in mHSPC (5%), which warrants further investigation. This study was limited by variability in methodology and definitions used among the eligible studies, including differences in sequencing methods, analytes (being either tissue or liquid), alteration calling thresholds, and target patient populations with a relative under-representation of recurrent metastatic disease.

CONCLUSIONS

Several genomic alterations are associated with differential prognosis and clinical phenotypes in mHSPC. We urge that emerging data on these potential predictive biomarkers must be validated in biomarker-driven randomised controlled trials before any clinical implementation. Alignment of the assay methodology and reporting will be critical for ensuring rapid scalability.

PATIENT SUMMARY

We reviewed current data on genomic alterations of metastatic hormone-sensitive prostate cancer, and summarised key genomic subtypes that associate with specific clinical phenotypes and treatment outcomes.

Predictive Genomic Biomarkers of Hormonal Therapy Versus Chemotherapy Benefit in Metastatic Castration-resistant Prostate Cancer

BACKGROUND

Biomarkers predicting second-generation novel hormonal therapy (NHT) benefit relative to taxanes are critical for optimized treatment decisions for metastatic castration-resistant prostate cancer (mCRPC) patients. These associations have not been reported simultaneously for common mCRPC genomic biomarkers.

OBJECTIVE

To evaluate predictive associations of common genomic aberrations in mCRPC using an established comprehensive genomic profiling (CGP) system.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study used data from a deidentified US-based clinicogenomic database comprising patients treated in routine clinical practice between 2011 and 2020, evaluated with Foundation Medicine CGP in tissue biopsies obtained around the time of treatment decision. The main cohort included 180 NHT and 179 taxane lines of therapy (LOTs) from 308 unique patients. The sequential cohort comprised a subset of the main cohort NHT LOTs immediately followed by taxane from 55 unique patients.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Prostate-specific antigen (PSA) response, time to next treatment (TTNT), and overall survival (OS) were assessed. Main cohort analyses were adjusted for known treatment assignment biases via inverse probability of treatment weighting (IPTW) in treatment interaction models.

RESULTS AND LIMITATIONS

In the main cohort, patients with AR amplification (ARamp) or PTEN aberrations (PTENalt) had worse relative PSA response on NHT versus taxanes compared with patients without. Patients with ARamp, PTENalt, or RB1 aberrations (RB1alt) also had worse relative TTNT and OS on NHT but not on taxanes. In multivariable models for TTNT and OS adjusted via IPTW, ARamp, PTENalt, and RB1alt were shown as poor prognostic factors overall and demonstrated significant treatment interactions, indicating reduced hazards of therapy switch and death on taxanes versus NHT. Consistent associations favoring increased benefit from subsequent taxane despite prior NHT treatment line were observed only for ARamp in the sequential cohort, in which very few patients had RB1alt for assessment.

CONCLUSIONS

ARamp status is a candidate biomarker to predict poor effectiveness of NHT relative to taxanes in mCRPC in scenarios where both options are considered.

PATIENT SUMMARY

Specific alterations in the DNA of tumors may assist in choosing between novel oral hormonal therapies and standard chemotherapy in advanced prostate cancer patients.

PARP Inhibition in Prostate Cancer With Homologous Recombination Repair Alterations

PURPOSE

With the broad use of next-generation sequencing assays, it has become clear that mutations in DNA repair genes are more commonly found than previously reported. In advanced prostate cancer patients with BRCA1/2 or ATM mutations, poly (ADP-ribose) polymerase inhibition (PARPi) causes an increased overall survival advantage compared with patients without these mutations. This review explores the advantages and limitations of PARPi treatment and its use beyond BRCA1/2-altered tumors. Furthermore, it discusses the benefits of current biomarkers and what role functional biomarkers and organoids may play in addressing the involvement of homologous recombination repair mutations in tumor development and progression.

METHODS

A systematic review was conducted in MEDLINE, National Library of Medicine, and ClinicalTrials.gov to identify studies published between January 1, 2016, and August 31, 2021. The search strategy incorporated terms for PARPi, BRCA, DNA damage, homologous recombination, organoids, patient-derived organoids, biomarker AND prostate cancer, breast cancer, ovarian cancer.

RESULTS

A total of 261 records remained after duplicate removal, 69 of which were included in the qualitative synthesis.

CONCLUSION

To improve the outcome of targeted therapy and increase sensitivity of tumor detection, patients should be repeatedly screened for DNA repair gene alterations and biomarkers. Future clinical studies should explore the use of PARPi beyond BRCA1/2 mutations and focus on finding new synthetically lethal interactions.

This review explores PARPi and its use for more than just BRCA1/2 altered tumors