Prognostic Value of Germline DNA Repair Gene Mutations in De Novo Metastatic and Castration-Sensitive Prostate Cancer

Homologous Recombination Repair Deficiency in Metastatic Prostate Cancer: New Therapeutic Opportunities

More than 20% of metastatic prostate cancer carries genomic defects involving DNA damage repair pathways, mainly in homologous recombination repair-related genes. The recent approval of olaparib has paved the way to precision medicine for the treatment of metastatic prostate cancer with PARP inhibitors in this subset of patients, especially in the case of BRCA1 or BRCA2 pathogenic/likely pathogenic variants. In face of this new therapeutic opportunity, many issues remain unsolved. This narrative review aims to describe the relationship between homologous recombination repair deficiency and prostate cancer, the techniques used to determine homologous recombination repair status in prostate cancer, the crosstalk between homologous recombination repair and the androgen receptor pathway, the current evidence on PARP inhibitors activity in metastatic prostate cancer also in homologous recombination repair-proficient tumors, as well as emerging mechanisms of resistance to PARP inhibitors. The possibility of combination therapies including a PARP inhibitor is an attractive option, and more robust data are awaited from ongoing phase II and phase III trials outlined in this manuscript.

Mismatch repair gene germline mutations in patients with prostate cancer

OBJECTIVES

To investigate the prevalence of pathogenic germline mutations of mismatch repair (MMR) genes in prostate cancer patients and its relationship with clinicopathological characteristics.

METHODS

Germline sequencing data of 855 prostate cancer patients admitted in Fudan University Shanghai Cancer Center from 2018 to 2022 were retrospectively analyzed. The pathogenicity of mutations was assessed according to the American College of Medical Genetics and Genomics (ACMG) standard guideline, Clinvar and Intervar databases. The clinicopathological characteristics and responses to castration treatment were compared among patients with MMR gene mutation (MMR+ group), patients with DNA damage repair (DDR) gene germline pathogenic mutation without MMR gene (DDR+MMR－ group) and patients without DDR gene germline pathogenic mutation (DDR－ group).

RESULTS

Thirteen (1.52%) MMR+ patients were identified in 855 prostate cancer patients, including 1 case with MLH1 gene mutation, 6 cases with MSH2 gene mutation, 4 cases with MSH6 gene mutation and 2 cases with PMS2 gene mutation. 105 (11.9%) patients were identified as DDR gene positive (except MMR gene), and 737 (86.2%) patients were DDR gene negative. Compared with DDR－ group, MMR+ group had lower age of onset (P<0.05) and initial prostate-specific antigen (PSA) (P<0.01), while no significant differences were found between the two groups in Gleason score and TMN staging (both P>0.05). The median time to castration resistance was 8 months (95%CI: 6 months-not achieved), 16 months (95%CI: 12-32 months) and 24 months (95%CI: 21-27 months) for MMR+ group, DDR+MMR－ group and DDR－ group, respectively. The time to castration resistance in MMR+ group was significantly shorter than that in DDR+MMR－ group and DDR－ group (both P<0.01), while there was no significant difference between DDR+MMR－ group and DDR－ group (P>0.05).

CONCLUSIONS

MMR gene mutation testing is recommended for prostate cancer patients with early onset, low initial PSA, metastasis or early resistance to castration therapy.

Characteristics of BRCA2 Mutated Prostate Cancer at Presentation

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

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

Objective

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

Materials and methods

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

Results

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

Conclusion

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

DNA damage repair gene germline profiling for metastatic prostate cancer patients of different ancestries

BACKGROUND

Germline and somatic mutations in DNA damage repair genes (DDRg) are now recognized as new biomarkers for the management of metastatic prostate cancers (mPC). We evaluate the frequency of germline DDRg mutations among French mPC patients of European and African ancestries.

METHODS

Targeted next-generation sequencing of 21 DDRg was performed on germline DNA from 557 mPC patients, including 15.1% of cases with an African origin.

RESULTS

Forty-seven germline mutations in 11 DDR genes were identified in 46 patients of the total cohort (8.3%). BRCA2 (4.1%) and ATM (2.0%) were the most frequently mutated genes. There was no difference in DDRg mutation frequency between mPC patients of European ancestry and those of African origin. Germline mutations of BRCA2 were associated with a positive family history of breast cancer (p = 0.02). The mean age at metastatic stage (59.7 vs. 67.0; p = 0.0003) and the mean age at death (65.2 vs. 73.9; p = 0.0003) were significantly earlier for carriers of BRCA2 mutation than for non-carriers. Moreover, the Cox model showed that BRCA2 positive status was statistically associated with poorer survival (hazard ratio: 0.29; 95% confidence interval 0.18-0.48; p < 0.0001).

CONCLUSION

We showed that, in France, BRCA2 and ATM are the main predisposing DDR genes in mPC patients, with a particular aggressiveness for BRCA2 leading to early metastatic stage and death.

Genomic Profiling of Prostate Cancer: An Updated Review

Understanding the genomic profiling of prostate cancer is crucial, owing to the emergence of precision medicine to guide therapeutic approaches. Over the last decade, integrative genomic profiling of prostate tumors has provided insights that improve the understanding and treatment of the disease. Minimally invasive liquid biopsy procedures have emerged to investigate cancer-related molecules with the advantage of detecting heterogeneity as well as acquired resistance in cancer. The metastatic castration-resistant prostate cancer (mCRPC) tumors have a highly complex genomic landscape compared to primary prostate tumors; a number of mCRPC harbor clinically actionable molecular alterations, including DNA damage repair (e.g., BRCA1/2 and ATM) and PTEN/phosphoinositide 3-kinase signaling. Heterogeneity in the genomic landscape of prostate cancer has become apparent and genomic alterations of TP53, RB1, AR, and cell cycle pathway are associated with poor clinical outcomes in patients. Prostate cancer with mutant SPOP shows a distinct pattern of genomic alterations, associating with better clinical outcomes. Several genomic profiling tests, which can be used in the clinic, are approved by the U.S. Food and Drug Administration, including MSK-IMPACT, FoundationOne CDx, and FoundationOne Liquid CDx. Here, we review emerging evidence for genomic profiling of prostate cancer, especially focusing on associations between genomic alteration and clinical outcome, liquid biopsy, and actionable molecular alterations.

Rucaparib and olaparib for the treatment of prostate cancer: A clinician's guide to choice of therapy

OBJECTIVE

This review will provide an overview of the use rucaparib and olaparib in patients with metastatic castration resistant prostate cancer (mCRPC) with the goal to assist the clinician's decision-making process when considering these agents for an individual patient.

DATA SOURCES

Searches were conducted in PubMed, relevant meeting abstracts, clinicaltrials.gov, and United States Food and Drug Administration (FDA) documents to identify literature published through July 1, 2021, related to use of rucaparib and olaparib for treatment of prostate cancer.

DATA SUMMARY

In May 2020, the FDA approved rucaparib and olaparib for treatment of mCRPC that is homologous recombination repair (HRR)-deficient. Both agents are approved for previously-treated patients, but there are notable differences in strength of evidence, outcomes studied, required HRR alteration, and required prior therapies. In patients who qualify for therapy, additional factors that may help guide choice of PARP inhibitor include baseline organ function, drug interaction potential, toxicity profiles, and financial factors.

CONCLUSIONS

Rucaparib and olaparib have the potential to improve outcomes for patients with HRR-deficient mCRPC. Differences in strength of evidence and patient- and drug-specific characteristics will assist the clinician when choosing between agents.

Response prediction biomarkers and drug combinations of PARP inhibitors in prostate cancer

PARP inhibitors are a group of inhibitors targeting poly(ADP-ribose) polymerases (PARP1 or PARP2) involved in DNA repair and transcriptional regulation, which may induce synthetic lethality in BRCAness tumors. Systematic analyzes of genomic sequencing in prostate cancer show that ~10%-19% of patients with primary prostate cancer have inactivated DNA repair genes, with a notably higher proportion of 23%-27% in patients with metastatic castration-resistant prostate cancer (mCRPC). These characteristic genomic alterations confer possible vulnerability to PARP inhibitors in patients with mCRPC who benefit only modestly from other therapies. However, only a small proportion of patients with mCRPC shows sensitivity to PARP inhibitors, and these sensitive patients cannot be fully identified by existing response prediction biomarkers. In this review, we provide an overview of the potential response prediction biomarkers and synergistic combinations studied in the preclinical and clinical stages, which may expand the population of patients with prostate cancer who may benefit from PARP inhibitors.

Comprehensive analysis of DNA damage repair deficiency in 10,284 pan-cancer study

Background

Disruption of the DNA damage repair (DDR) gene is related to cancer progression, treatment selection, and is subjected to radiation and targeted therapies with limited success. This paper conducted a comprehensive analysis to explore the distribution of DDR mutations in Chinese pan-cancer patients.

Methods

A total of 10,284 consecutive cases were analyzed in 24 cancer types [non-small cell lung cancer (NSCLC) 29.0%, liver 12.0%, colorectum 10.7%, etc.]. Tumor tissue samples were subjected to next generation sequencing (NGS) using a 381 gene panel incorporating 100 microsatellite loci. The association of deleterious somatic DDR mutation (del-sDDR^mut) with tumor mutational burden (TMB), microsatellite instability (MSI), programmed cell death-ligand 1 (PD-L1) expression of pan-cancers was evaluated. Genomic and clinical data from public cohorts of immunotherapy were analyzed to demonstrate the association between del-sDDR^mut and clinical survival.

Results

Del-sDDR^mut were found in 802 (7.6%) of all cases, and were most common in cancers of the endometrium, prostate, bladder, etc. cancer with a higher TMB also had a higher prevalence of mutations in DDR pathways. The results of the ridge regression analysis showed that 20 DDR genes were significantly associated with TMB [false discovery rate (FDR) <0.01]. A total of 8,899 patients had both TMB and MSI-data in pan-cancers. Seventy-four percent of patients with MSI-high (MSI-H) were accompanied by del-sDDR^mut/TMB-high (TMB-H). The largest proportion of patients with microsatellite stability (MSS) with DDR mutations were classified as TMB-H. The top 6 tumors (NSCLC, melanoma, esophagus, head and neck, thyroid, and mediastinal) had the highest prevalence of PD-L1 ≥1%, and DDR mutations were significantly associated with a higher percent of PD-L1 positive (P<0.05). Furthermore, in the immune cohort analysis of NSCLC, patients with del-sDDR^mut significantly improved median progression-free survival (mPFS) and median overall survival (mOS) compared to wild-type DDR patients (P=0.002 and P=0.043), with higher TMB observed (P<0.001).

Conclusions

This study explored the association of DDR mutations with TMB, MSI-H, and PD-L1 expression, and revealed that patients with DDR mutations have a significantly improve prognosis than wild-type patients on immunotherapy.

Inherited Mutations in Chinese Men With Prostate Cancer

BACKGROUND

Although China accounts for 7.8% of worldwide new prostate cancer (PCa) cases and 14.5% of new deaths according to GLOBOCAN 2020, the risk of PCa associated with germline mutations is poorly defined, hampered in part by lack of nationwide evidence. Here, we sequenced 19 PCa predisposition genes in 1,836 Chinese patients with PCa and estimated disease risk associated with inherited mutations.

PATIENTS AND METHODS

Patients were recruited from 4 tertiary cancer centers (n=1,160) and a commercial laboratory (n=676). Germline DNA was sequenced using a multigene panel, and pathogenic/likely pathogenic (P/LP) mutation frequencies in patients with PCa were compared with populations from the gnomAD (Genome Aggregation Database) and ChinaMAP (China Metabolic Analytics Project) databases. Clinical characteristics and progression-free survival were assessed by mutation status.

RESULTS

Of 1,160 patients from hospitals, 89.7% had Gleason scores ≥8, and 65.6% had metastases. P/LP mutations were identified in 8.49% of Chinese patients with PCa. Association with PCa risk was significant for mutations in ATM (odds ratio [OR], 5.9; 95% CI, 3.1-11.1), BRCA2 (OR, 15.3; 95% CI, 10.0-23.2), MSH2 (OR, 15.8; 95% CI, 4.2-59.6), and PALB2 (OR, 5.9; 95% CI, 2.7-13.2). Compared with those without mutations, patients with mutations in ATM, BRCA2, MSH2, or PALB2 showed a poor outcome with treatment using androgen deprivation therapy and abiraterone (hazard ratio, 2.19 [95% CI, 1.34-3.58] and 2.47 [95% CI, 1.23-4.96], respectively) but similar benefit from docetaxel.

CONCLUSIONS

The present multicenter study confirmed that a significant proportion of Chinese patients with PCa had inherited mutations and identified predisposition genes in this underreported ethnicity. These data provide empirical evidence for precision prevention and prognostic estimation in Chinese patients with PCa.

Current and Emerging Therapies for Metastatic Castration-Resistant Prostate Cancer (mCRPC)

Metastatic castration-resistant prostate cancer (mCRPC) encompasses a heterogeneous wide range of molecular tumor behavior and a high risk of progression. Early detection and treatment are therefore crucial in these patients. Treatment has improved drastically in recent years and many novel therapeutic agents are currently under investigation. However, due to the rapidly changing therapeutic landscape in mCRPC, it is difficult for clinicians to keep up to date with the latest innovations in this area. In the present narrative review, we discuss the current and emerging therapies for mCRPC as well as the clinical and molecular factors that can help predict which patients are most likely to benefit from these novel agents.

Homologous recombination repair gene mutations in Chinese localized and locally advanced prostate cancer patients

BACKGROUND

Homologous recombination repair gene (HRR) mutations have been proven to be effective biomarkers for PARP inhibitor therapy for metastatic castration resistant prostate cancer. However, the frequency of HRR mutations in patients with localized and locally advanced prostate cancer is still unclear. This study investigated the profile of HRR gene mutations in Chinese localized and locally advanced prostate cancer patients.

MATERIALS AND METHODS

74 patients with localized and locally advanced prostate cancer patients in Beijing Chaoyang Hospital between May 2018 and September 2019 were retrospectively included. Matched prostate cancer and histologically normal tissues were subjected to next-generation sequencing. Pathogenic alterations of 19 HRR genes were examined.

RESULTS

Ten deleterious and suspected deleterious mutations (4 germline and 6 somatic mutations) were detected in 9 of 74 (12.16 %) patients, occurred in seven HRR-related genes, including CDK12, NBN, ATM, ATR, BRCA2, PALB2 and RAD51C. The mutation frequency of HRR genes in this study (12.16 %) was higher than TCGA cohort (7.29 %), and the mutation sites in 7 HRR genes detected in this cohort were different from those of TCGA data. Patients with HRR gene mutations had higher Gleason grade (≥ 3) (P = 0.03) and risk level (very-high) (P = 0.03). Postoperative prostate specific antigen level and positive surgical margin rate was not associated with HRR gene mutation status.

CONCLUSIONS

This study illustrated the mutation patterns of HRR genes in Chinese population with localized and locally advanced prostate cancer. These results provide further evidence that HRR gene mutations were more prevalent in patients with higher Gleason grade, or with very-high-risk level. Patients with these clinicopathologic characteristics may need more precise stratification through molecular detection.

Population-Based Study of Docetaxel or Abiraterone Effectiveness and Predictive Markers of Progression Free Survival in Metastatic Castration-Sensitive Prostate Cancer

BACKGROUND

Both Docetaxel (DOC) and Abiraterone (ABI) improve the survival of men with metastatic, castration sensitive prostate cancer (mCSPC). However, the outcome among mCSPC patients is highly variable, while there is a lack of predictive markers of therapeutic benefit. Furthermore, there is limited data on the comparative real-world effectiveness of adding DOC or ABI to androgen deprivation therapy (ADT).

METHODS

We conducted a retrospective analysis of 121 mCSPC patients treated at Odette Cancer Centre (Toronto, ON, Canada) between Dec 2014 and Mar 2021 (DOC n = 79, ABI n = 42). The primary endpoint studied was progression free survival (PFS), defined as the interval from start of ADT to either (i) biochemical, radiological, or symptomatic progression, (ii) start of first-line systemic therapy for castration-resistant prostate cancer (CRPC), or (iii) death, whichever occurred first. To identify independent predictive factors for PFS in the entire cohort, a Cox proportional hazard model (stepwise selection) was applied. Overall survival (OS) was among secondary endpoints.

RESULTS

After a median follow-up of 39.6 and 25.1 months in the DOC and ABI cohorts, respectively, 79.7% of men in the DOC and 40.5% in the ABI group experienced a progression event. PFS favored the ABI cohort (p = 0.0038, log-rank test), with 78.0% (95%CI 66.4-91.8%) of ABI versus 67.1% (57.5-78.3%) of DOC patients being free of progression at 12 months. In univariate analysis superior PFS was significantly related to older age at diagnosis of mCSPC, metachronous metastatic presentation, low-volume (CHAARTED), and low-risk (LATITUDE) disease, ≥90% PSA decrease at 3 months (PSA90), and PSA nadir ≤0.2 at 6 months. Age (HR = 0.955), PSA90 (HR = 0.462), and LATITUDE risk stratification (HR = 1.965) remained significantly associated with PFS in multivariable analysis. OS at 12 months was 98.7% (96.3-100%) and 92.7% (85.0-100%) in the DOC and ABI groups (p = 0.97), respectively.

CONCLUSIONS

In this real-world group of men undergoing treatment intensification with DOC or ABI for mCSPC, we did not find a significant difference in OS, but PFS was favoring ABI. Age at diagnosis of mCSPC, PSA90 at 3 months and LATITUDE risk classification are predictive factors of PFS in men with mCSPC.

Treatment Strategies for Metastatic Castration-Sensitive Prostate Cancer: From "All-Comers" to "Personalized" Approach

Standard treatment for metastatic castration-sensitive prostate cancer (mCSPC) was androgen-deprivation therapy (ADT) for >7 decades, and this was termed the “all-comers” approach. A remarkable evolution in the treatment of mCSPC has been noted in the previous several years. High-quality clinical trials have shown that the addition of docetaxel or androgen receptor pathway inhibitors, such as abiraterone acetate, enzalutamide, and apalutamide, to ADT improves the overall survival (OS) as compared to ADT alone. The first 2 trials demonstrated the benefits of docetaxel and abiraterone acetate in terms of OS in high-volume and high-risk cancer subgroups, respectively. The later trials indicated that upfront combination therapies were associated with improved OS in all patients, irrespective of tumor volume and risk category. Upfront combination therapies are becoming a standard of care for all patients with mCSPC. However, meta-analyses have failed to show that all upfront combination therapies provide significant survival benefits in all patient subgroups. In the low-volume subgroup, significance was observed only for treatment with enzalutamide and radiation to the prostate. Men with low-volume low-risk cancer who have favorable response to ADT achieve long-term survival with ADT only, and toxicities induced by combination therapies would exceed the benefit for these patients. Treatments should be tailored to each patient because mCSPC has marked diversity in its biological and clinical features. Recent advances in diagnostic and molecular technologies will provide useful prognostic and predictive biomarkers, and the treatment strategy will shift from the “for all-comers” to the “individualized” approach.

Differential treatment outcomes in BRCA1/2-, CDK12-, and ATM-mutated metastatic castration-resistant prostate cancer

BACKGROUND

DNA damage repair mutations (DDRm) are common in patients with metastatic castration-resistant prostate cancer (mCRPC). The optimal standard therapy for this population is not well described.

METHODS

A multi-institutional, retrospective study of patients with mCRPC and DDRm was conducted. Patient data, including systemic therapies and responses, were collected. The decline in prostate-specific antigen ≥ 50% from baseline (PSA50) and overall survival (OS) from the treatment start were compared by mutation and treatment type. A multivariable Cox proportional hazards model for OS was created that controlled for DDRm, first-line treatment received for mCRPC, and clinical factors.

RESULTS

The most common DDRm observed among 149 men with mCRPC were BRCA1/2 (44%), CDK12 (32%), and ATM (15%). The majority received first-line abiraterone (40%) or enzalutamide (30%). The PSA50 rate with first-line abiraterone was lower for CDK12 (52%) than BRCA1/2 (89%; P = .02). After first-line abiraterone or enzalutamide, the median OS was longest with second-line carboplatin-chemotherapy (38 months) in comparison with abiraterone or enzalutamide (33 months), docetaxel (17 months), or cabazitaxel (11 months; P = .02). PSA50 responses to carboplatin-based chemotherapy were higher for BRCA1/2 (79%) than ATM (14%; P = .02) or CDK12 (38%; P = .08). In a multivariable analysis, neither the specific DDRm type nor the first-line treatment was associated with improved OS.

CONCLUSIONS

Responses to standard therapies were generally superior in patients with BRCA1/2 mutations and inferior in patients with ATM or CDK12 mutations. The DDRm type did not independently predict OS. After progression on first-line abiraterone or enzalutamide, carboplatin-based chemotherapy was associated with the longest OS. These findings may inform treatment discussions and clinical trial design and require prospective validation.

DNA damage repair gene mutation testing and genetic counseling in men with/without prostate cancer: a systematic review

Background: Ongoing clinical trials are investigating PARP inhibitors to target the DNA damage repair (DDR) pathway in prostate cancer. DDR mutation screening will guide treatment strategy and assess eligibility for clinical trials. Materials & methods: This systematic review estimated the rate of DDR mutation testing or genetic counseling among men with or at risk of prostate cancer. Results: From 6856 records, one study fulfilled the inclusion criteria and described men undiagnosed with prostate cancer with a family history of BRCA1/2 mutation who received DDR mutation testing. Conclusion: With only one study included in this first systematic review of DDR mutation testing or genetic counseling in men with or at risk of prostate cancer, more research is warranted.

Long-Term Disease Control Using Taxane/Platinum-Based Chemotherapy in CDK12-Mutated Advanced Prostate Cancer

This letter to the editor describes a patient with metastatic prostate cancer harboring a biallelic somatic CDK12 mutation and their response to a platinum-based combination therapy.