Germline Mutations In DNA Repair Genes Research Articles

Prevalence of DNA-Repair Gene Mutations in Mexican Men with Prostate Cancer

Introduction and objectiveMexico reported 26,742 new cases of prostate cancer in 2020. Different risk factors have been identified in the pathogenesis of prostate cancer. Among them, genetic factors and alterations or mutations in specific genes have been described in different ethnic groups worldwide. The aim of our study is to report the prevalence of germline DNA-repair gene mutations in Mexican patients with prostate cancer. Material and methodWe performed germline genetic testing in 50 patients with localized prostate cancer and 50 patients with metastatic prostate cancer. Demographic, clinical, and histopathological data were collected. ResultsThirty-seven germline mutations were identified in 32 patients. The most commonly affected genes were ATM in 6%, followed by FANCA (5%), and ATR (4%). BRCA2 mutations were identified in 3%. The frequency of mutations was higher in the metastatic group. Discussion and ConclusionThe results of our study show different mutations from those reported in different populations or regions. The use of PARP inhibitors is indicated in patients with germline mutations, specifically BRCA2, showing improvement in overall survival and progression free survival. To our knowledge, this is the first study reporting the prevalence of mutations in DNA-repair genes in Mexican patients with prostate cancer.

Prevalencia de mutaciones en genes de reparación en hombres mexicanos con cáncer de próstata

Introduction and objectiveMexico reported 26,742 new cases of prostate cancer in 2020. Different risk factors have been identified in the pathogenesis of prostate cancer. Among them, genetic factors and alterations or mutations in specific genes have been described in different ethnic groups worldwide. The aim of our study is to report the prevalence of germline DNA-repair gene mutations in Mexican patients with prostate cancer. Material and methodWe performed germline genetic testing in 50 patients with localized prostate cancer and 50 patients with metastatic prostate cancer. Demographic, clinical, and histopathological data were collected. ResultsThirty-seven germline mutations were identified in 32 patients. The most commonly affected genes were ATM in 6%, followed by FANCA (5%), and ATR (4%). BRCA2 mutations were identified in 3%. The frequency of mutations was higher in the metastatic group. Discussion and ConclusionThe results of our study show different mutations from those reported in different populations or regions. The use of PARP inhibitors is indicated in patients with germline mutations, specifically BRCA2, showing improvement in overall survival and progression free survival. To our knowledge, this is the first study reporting the prevalence of mutations in DNA-repair genes in Mexican patients with prostate cancer.

TRIUMPH: Phase II trial of rucaparib monotherapy in patients with metastatic hormone-sensitive prostate cancer harboring germline DNA repair gene mutations.

190 Background: Androgen deprivation therapy (ADT) is the backbone of treatment for patients (pts) with metastatic prostate cancer (PCa), but many pts find this difficult to tolerate. Treatment with non-castrating regimens may avoid or delay the toxicities of hormonal therapy. The activity of PARP inhibitors (PARPi) in pts with homologous recombination DNA-repair (HRD) mutations (muts) and metastatic castration-resistant PCa has been established. We hypothesized here that the benefit of ARPi can be maintained in the absence of ADT in a biomarker-selected (HRD mutated) population with PCa. We designed a Phase 2 study in men with hormone-naïve, metastatic PCa who harbored a germline HRD mut treated with rucaparib monotherapy (without ADT). Methods: This was a multi-center, single arm Phase 2 study (NCT03413995) in men with asymptomatic hormone-sensitive metastatic PCa who received rucaparib 600mg by mouth daily. During consenting, pts were informed and had to opt out of ADT-based therapy. Pts must have had a germline mutation in an HRD gene on clinical-grade testing. The primary endpoint was confirmed PSA50 response rate. Key secondary endpoints included safety, objective response rate (ORR), and radiographic progression-free survival (rPFS). The trial was designed to detect a 25% absolute increase in PSA50 response from a null of 50%. Results: 12 pts were enrolled, 7 with BRCA1/2 and 5 with CHEK2 muts. The confirmed PSA50 response rate to rucaparib was 41.7% (N=5/12, 95% CI: 19.3-68.1%), which did not meet the pre-specified efficacy boundary to enroll additional patients to 2nd stage. In pts with measurable disease, the ORR was 60% (N=3/5, all with BRCA2). Median rPFS on rucaparib was 10.3 months (95% CI: 4.0 mo - NR). At the time of the interim analysis, 3 pts remained on study. The majority of adverse events (AE) were Grade ≤2 and expected. Translational studies are ongoing. Conclusions: Rucaparib can induce clinical responses in a biomarker-selected PCa population without concurrent ADT. However, the pre-specified threshold of PSA50 response was not met. Although durable responses were observed in a subset of pts, PARPi without ADT in metastatic hormone sensitive PCa will not be pursued. Clinical trial information: NCT03413995 . [Table: see text]

Awareness of genetic risk for prostate cancer (PCa) in men from families with germline mutations in DNA-repair genes.

328 Background: Although one of the most important risk factors for prostate cancer (PCa) is a family history of the disease, there is a poor awareness of genetic risk. The aim of the current study is to investigate the awareness of genetic risk for PCa in men belonging to female families with germline variants in DNA-repair genes (DRGs). Methods: Data were extracted by a prospective observational study designed to select men with germline pathogenic variants (PVs) and offer them a dedicated PCa screening. The selection of probands was performed by genetic counseling and testing of male grade I relatives of female patients with a PVs. Male candidates were identified after reviewing the genealogical trees of all women who had received the diagnosis of breast and/or ovarian cancer and tested positive for a PVs. All the probands, 35-69 yrs old, who resulted positive for PVs were offered to participate to a specific PCa screening based on annually digital rectal examination (DRE), detection of PHI, which is a blood test including total PSA, free PSA, free/total PSA and -2proPSA, and multiparametric MRI. The primary outcome was the “willing to be tested”, defined as a proxy for male awareness of PCa risk. The secondary endpoint was the acceptance rate to be screened. Results: We reviewed the genealogical trees of breast/ovarian cancer female patients from January 2017 to December 2021 and we identified, over 1256 families, 139 positive cases for PVs in DRGs. Among 139 families, we identified 378 “healthy” 35-69 yrs old men, who were offered a genetic counseling, and if they agree a genetic testing. Overall 117/378 (31%) healthy males declared to be interested to be tested. Out of the 51 new tests (66 men already tested out of the study), we found 30 (58.8%) positive men. All the new positive tested men accepted to attend the PCa screening. Living in Northern Italy, having at least one child and higher (degree) level of education were the strongest predictors of willing for testing (p<0.01). Conclusions: Our data reveals a limited will to be tested, but all men tested positive for PVs accepted to participate to the PCa screening. These findings strongly support the urgent need to implement awareness of genetic risk for PCa.

P015 - A dedicated screening for early detection of Prostate cancer (Pca) in men with germline mutations in DNA-Repair Genes (DRG)

P015 - A dedicated screening for early detection of Prostate cancer (Pca) in men with germline mutations in DNA-Repair Genes (DRG)

SC142 - A dedicated screening for early detection of prostate cancer in men with germline mutations in DNA-repair genes

SC142 - A dedicated screening for early detection of prostate cancer in men with germline mutations in DNA-repair genes

SC99 - Male awareness of prostate cancer risk remains poor in families with germline mutations in dna-repair genes

SC99 - Male awareness of prostate cancer risk remains poor in families with germline mutations in dna-repair genes

PD11-07 AWARENESS OF RISK OF PROSTATE CANCER (PCA) REMAINS POOR IN FAMILIES WITH GERMLINE MUTATIONS IN DNA-REPAIR GENES

You have accessJournal of UrologyCME1 May 2022PD11-07 AWARENESS OF RISK OF PROSTATE CANCER (PCA) REMAINS POOR IN FAMILIES WITH GERMLINE MUTATIONS IN DNA-REPAIR GENES Giuseppe Chiarelli, Rodolfo Hurle, Paolo Casale, Alberto Saita, Giovanni Lughezzani, Vittorio Fasulo, Alessio Benetti, Giorgio Guazzoni, Massimo Lazzeri, NicolòMaria Buffi, Monica Zuradelli, and Massimo Lazzeri Giuseppe ChiarelliGiuseppe Chiarelli More articles by this author , Rodolfo HurleRodolfo Hurle More articles by this author , Paolo CasalePaolo Casale More articles by this author , Alberto SaitaAlberto Saita More articles by this author , Giovanni LughezzaniGiovanni Lughezzani More articles by this author , Vittorio FasuloVittorio Fasulo More articles by this author , Alessio BenettiAlessio Benetti More articles by this author , Giorgio GuazzoniGiorgio Guazzoni More articles by this author , Massimo LazzeriMassimo Lazzeri More articles by this author , NicolòMaria BuffiNicolòMaria Buffi More articles by this author , Monica ZuradelliMonica Zuradelli More articles by this author , and Massimo LazzeriMassimo Lazzeri More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002537.07AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: About 5-10% of PCa correlate with an inherited susceptibility. Germline mutations in DNA-repair genes (DRG) were found in approximately 5% of localized PCa and in 12% of metastatic castration-resistant PCa. As DRG mutations correlate with PCa aggressiveness there is an urgent need to test individuals suspected to be carriers who most benefit from early diagnosis and personalized therapies. The aim of the present study is to investigate the awareness of risk of PCa in families with germline mutations in DRG. METHODS: This is a prospective, monocentric study of families with DRG mutations. Those families ere selected from all families of women with breast and/or ovarian cancer treated in the last 5 years at the Breast Unit of our tertiary University Hospital. To test the awareness of risk of PCa we used the ratio between the number of families (where at least one man was present, who was offered the test for mutation detection) and probands who were really tested. Willingness to be tested was stratified according demographic, educational status and geographical residence. Healthy men with DRG mutations were offered a dedicated annual PCa screening consisting of digital rectal examination (DRE), blood test for Prostate Health Index (PHI) and multiparametric MRI with software assisted target biopsy plus systematic biopsy in suspected cases. RESULTS: Reviewing the genealogical trees of all breast/ovarian cancer patients who attended our Genetic Counselling Clinic from January 2016 to May 2021, we identified, over 1083 families, 132 positive ones for mutations in DRG. Over 132 families, we found that all the male members of 62 rejected to be tested. The original parent branch of mutation was unknown in 24 families and limited the interest in male relatives. In 9 families no male relatives were present; in 5 families, all men were already tested negative; probands were missed in 8. Finally, we selected 29 families (25%) with at least one male relative willing to be tested. We identified 59 men with a DRG mutation, of whom 27 met the inclusion criteria for screening and started it. Living in Northern Italy, higher educational levels, being married, the presence of offspring and at least one first-degree relative affected with cancer correlated with a higher willingness to be tested (p <0.05). No correlation between age at genetic counselling and test acceptance was found. CONCLUSIONS: Our analysis showed that only 25% of men with a high-risk of developing PCa accepted a genetic profiling, limiting their access to a dedicated PCa screening. This observation strongly supports the urgent need to implement awareness of genetic risk for PCa within male population. Source of Funding: This work was supported by AIRC (Associazione Italiana Ricerca sul Cancro), grant number IG 2020 ID 25027 © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e192 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Giuseppe Chiarelli More articles by this author Rodolfo Hurle More articles by this author Paolo Casale More articles by this author Alberto Saita More articles by this author Giovanni Lughezzani More articles by this author Vittorio Fasulo More articles by this author Alessio Benetti More articles by this author Giorgio Guazzoni More articles by this author Massimo Lazzeri More articles by this author NicolòMaria Buffi More articles by this author Monica Zuradelli More articles by this author Massimo Lazzeri More articles by this author Expand All Advertisement PDF DownloadLoading ...

A0353 - Awareness of risk of prostate cancer (PCa) remains poor in families with germline mutations in DNA-repair genes

A0353 - Awareness of risk of prostate cancer (PCa) remains poor in families with germline mutations in DNA-repair genes

Abstract 2500: The Forkhead-like protein Dach1 governs sensitivity to WEE1 kinase and PARP inhibitors

Abstract Molecular analysis of all cancer types in the cancer genome atlas (TCGA) demonstrated that multiple pathways may be disrupted within a given tumor including PCa. Prostate cancer (PCa), the second leading cause of death in American men, includes distinct genetic subtypes with distinct therapeutic vulnerabilities. Substratification of PCa into genetic subtypes, forms the basis of rational therapy for PCa. Known genetic drivers to PCa include deletions of target genes (PTEN and NKX3.1 deletions), rearrangements/fusions of multiple genes (including TMPRSS2 and the oncogenic ETS transcription factor, ERG) and genetic predisposing factors (including germline DNA-repair gene mutations). An increasingly common finding in PCa are defects in DNA repair. The Drosophila Dac gene was initially cloned as dominant inhibitor of Elipse. The human homologue, DACH1, encodes a winged helix/Forkhead DNA-binding protein that binds in chromatin to FOXM1 sites. Herein, reduced expression of DACH1 is shown in PCa, correlating with DACH1 promoter methylation. Homozygous deletion of DACH1 occurred in up to 18% of human PCa, associated with increased AR activity, increased somatic copy-number alteration and poor prognosis. DACH1 increased DNA repair, as shown in comet assays, enhancing nonhomologous end joining (NHEJ) while reducing homology directed repair (HDR) in DNA repair reporter assays. Laser wounding showed DACH1 was recruited to sites of DNA damage, augmenting the recruitment of Ku70/Ku80. In Dach1 deletion cells reduced expression of Dach1 was associated with resistance to inhibitors of Poly-(ADP)-ribose polymerase (PARP) and enhanced sensitivity to inhibitors of WEE1 kinase and DNA-PK. The abundance of DACH1 in prostate cancer may define a subclass of prostate cancer warranting selective therapies. Citation Format: Zhiping Li, Xuanmao Jiao, A. Gordon Robertson, Anthony W. Ashton, Andrew Kossenkov, Hao Chen, Lai Yee Phoon, Li Lan, Richard G. Pestell. The Forkhead-like protein Dach1 governs sensitivity to WEE1 kinase and PARP inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2500.

Genetics of prostate cancer and its utility in treatment and screening.

Prostate cancer heritability is attributed to a combination of rare, moderate to highly penetrant genetic variants as well as commonly occurring variants conferring modest risks [single nucleotide polymorphisms (SNPs)]. Some of the former type of variants (e.g., BRCA2 mutations) predispose particularly to aggressive prostate cancer and confer poorer prognoses compared to men who do not carry mutations. Molecularly targeted treatments such as PARP inhibitors have improved outcomes in men carrying somatic and/or germline DNA repair gene mutations. Ongoing clinical trials are exploring other molecular targeted approaches based on prostate cancer somatic alterations. Genome wide association studies have identified >250 loci that associate with prostate cancer risk. Multi-ancestry analyses have identified shared as well as population specific risk SNPs. Prostate cancer risk SNPs can be used to estimate a polygenic risk score (PRS) to determine an individual's genetic risk of prostate cancer. The odds ratio of prostate cancer development in men whose PRS lies in the top 1% of the risk profile ranges from 9 to 11. Ongoing studies are investigating the utility of a prostate cancer PRS to target population screening to those at highest risk. With the advent of personalized medicine and development of DNA sequencing technologies, access to clinical genetic testing is increasing, and oncology guidelines from bodies such as NCCN and ESMO have been updated to provide criteria for germline testing of "at risk" healthy men as well as those with prostate cancer. Both germline and somatic prostate cancer research have significantly evolved in the past decade and will lead to further development of precision medicine approaches to prostate cancer treatment as well as potentially developing precision population screening models.

1128 - Prognostic value of germline DNA repair gene mutations in de novo metastatic and treatment-naïve prostate cancer

1128 - Prognostic value of germline DNA repair gene mutations in de novo metastatic and treatment-naïve prostate cancer

Germline DNA repair gene mutations in Taiwan prostate cancer patients.

e13640 Background: Genetic testing for inherited mutations in DNA-repair genes such as BRCA1, BRCA2, ATM, PALP2, FANCA has been proposed for high-risk and metastatic prostate cancer patients for personalized therapy and management. Although the prevalence of germline DNA-repair gene mutations among Caucasian populations are known, the frequency of such mutations in Taiwan prostate cancer patients has not been established. In this study, we performed next-generation sequencing (NGS) analysis of BRCA1, BRCA2, ATM, PALP2, and FANCA in 49 prostate cancer patients stratified according to the NCCN risk criteria using blood sample collected from a single hospital center. Methods: 4ml whole blood samples are collected in EDTA tube from prostate cancer patients of low-intermediate, high to very high, regional, and metastatic risks. The samples are subjected to buffy coat fractionation, genomic DNA extraction, library preparation, full-exon NGS, and comparative analysis with all known germline variants. We identified and correlated the frequency of germline DNA-repair gene mutations with patient’s age at diagnosis, Gleason grades, initial PSA, family history of prostate cancer, and NCCN risk. Results: A total of 49 blood samples were tested and analyzed for BRCA1, BRCA2, ATM, PALP2, and FANCA mutations. Among all cases, 6.1% (3/49, 95% confidence interval [CI]: - 0.6%-12.8%) carried pathogenic mutations: 2.0% (1/49) in BRCA1, 2.0% (1/49) in BRCA2, and 2.0% (1/49) in ATM. They were compatible with previously reported mutations and no new germline variants were detected. These mutations were associated with initial PSA and NCCN risk; all identified mutations belonged to Gleason grade 5 and high to very high risk subgroups. No clinical association was observed with patient’s age of diagnosis and family history. Conclusions: In this single hospital center study, we observed a modest incidence of DNA-repair gene mutations in the Taiwan prostate cancer cohort. Germline DNA-repair gene mutations were observed in high risk prostate cancer patients with the highest Gleason grade. Frequencies of the mutations did not differ significantly according to age at diagnosis or family history of prostate cancer. These results were similar to the reported findings in the Caucasian populations. Our findings confirmed the necessity of genetic testing in Taiwan prostate cancer patients. [Table: see text]

Germline mutations in DNA repair genes in a large series of unselected Chinese prostate cancer patients.

e17523 Background: Germline DNA repair gene (DRG) mutations has emerged as a potential determinant of cancer risk and therapeutic response in PCa. Despite substantial advances in delineating the germline mutation in DRGs among Caucasian population, the prevalence of mutations in DRGs are largely unknown among a large series of unselected prostate cancer patients in Chinese population. Methods: We enrolled 1003 prostate cancer patients from three different hospitals in China, unselected for family history of cancer or age at diagnosis. All patients received germline genetic testing using a clinician-selected multi-gene panel. The 18 DNA repair genes and HOXB13, which has established or emerging potential clinical actionability in PCa, were analyzed in our study. Results: A total of 94 (9.7%) deleterious germline mutations were identified among the 1003 unselected prostate cancer patients. Of these, 5.6% patients carried a BRCA1 or BRCA2 mutations (5.2% in BRCA2 and 0.4% in BRCA1), 3.6% patients carried other DRG mutations (including 10 genes) and 0.5% patients carried HOXB13 mutations. Besides, variants with uncertain significance (VUS) were found in approximately 45% patients. We also divided 633 metastatic PCa patients into 542 de novo metastastic PCa and 91 recurrent metastastic PCa and found mutation frequencies did not differ between these two groups (9.0% vs 11.6%, p = 0.6). Patients with younger age of onset or family history of cancers were more likely to harbour germline mutations in DRGs. However, the rate of germline mutations were still at a high level for patients more than 70 years old (6.7%) and patients without family history of cancers (7.5%). There is no statistically significant difference in the mutation frequencies between patients with metastasis and without metastasis (7.5% vs 9.2%, p = 0.4), which may be because 85% patients without metastasis in our cohort were in high to very high risk group or have lymph node metastasis. Conclusions: To our knowledge, our study reported the largested series of Chinese PCa patients who received germline genetic testing. Our study provided a rationality for germline genetic testing criteria from high risk to metastastic PCa regardless of family history considering the high proportion. In addition, we recommended a multigene panel covering 13 genes ( ATM, BRCA1, BRCA2, CHEK2, FANCA, HOXB13, MSH2, MSH6, NBN, PALB2, RAD51C, RAD51D, TP53) in China. Nevertheless, the high prevalence of VUS (45%) in Chinese PCa patients warrant further efforts.

Short-Term Outcomes of Active Surveillance for Low Risk Prostate Cancer among Men with Germline DNA Repair Gene Mutations.

Men with germline mutations in DNA repair genes have a higher risk of prostate cancer. Active surveillance is the preferred treatment modality for low risk prostate cancer. However, many fear offering this alternative to men with germline mutations. We describe the short-term oncologic outcomes of active surveillance in a population of men with a high genetic predisposition for prostate cancer. A prospective cohort of men with germline DNA repair gene mutations were diagnosed with Grade Group 1 prostate cancer. All men were offered active surveillance. Followup consisted of prostate specific antigen every 3 months, multiparametric magnetic resonance imaging and a magnetic resonance imaging-ultrasound fusion confirmatory biopsy within 1 year of diagnosis. The primary end points included treatment and progression-free survival. Eighteen carriers of DNA repair gene mutations were diagnosed with low risk prostate cancer (BRCA1 [8], BRCA2 [6], CHEK2 [2], Lynch syndrome [2]). Of these patients 15 (83%) initiated active surveillance and 3 (17%) declined. All but 1 were fully compliant with the active surveillance protocol (93%). Overall 20% (3) had upgrading at confirmatory biopsy and were treated. At a median followup of 28 months (IQR 8.5-42) 80% of patients (12) on active surveillance are free from upgrading or radical treatment. Active surveillance may be feasible among carriers diagnosed with low risk prostate cancer. If embarking on active surveillance, carriers should be very carefully monitored at a specialized clinic, optimizing patient compliance and minimizing risk. Until larger scale studies with long-term followup become available, this option should be cautiously discussed with the patient.

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

Germline DNA damage repair gene mutations (gDDRm) have been found in approximately 12% of patients with metastatic prostate cancer (mPCa). Previous studies of the clinical impact of gDDRm have mainly been in the setting of metastatic castration-resistant prostate cancer (mCRPC). This study aimed to determine the prognostic value of gDDRm in de novo metastatic and castration-sensitive prostate cancer (mCSPC). We retrospectively collected the records of 139 consecutive men with de novo mCSPC who initially received systemic therapies following guidelines. This included 128 patients who underwent genetic testing at our center and 11 patients referred to our center after being identified as gDDRm carriers. Time to mCRPC was collected. Kaplan-Meier and log-rank analysis were used to analyze the association between gDDRm and clinical outcomes. Survival outcomes were adjusted using multivariable Cox regression models. Of the 139 patients with de novo mCSPC, 28 gDDRm carriers were identified. Median time progressing to mCRPC was significantly shorter in patients carrying gDDRm than in those without mutations (8.3 vs 13.2 months; hazard ratio [HR], 2.37; p < .001). Moreover, median progression time was almost halved in BRCA2 carriers (6.3 vs. 13.2 months; HR, 3.73; p < .001). Subgroup analysis revealed that the presence of gDDRm indicated poor therapy response regardless of disease volume and prostate-specific antigen nadir within the first 7 months. Presence of gDDRm remained independently associated with increased risk of progression to mCRPC in multivariate analysis (adjusted HR, 1.98; p = .006). Our study suggested that positive gDDRm status predicted rapid progression to castration resistance in patients with de novo mCSPC. We propose identifying gDDRm status at the time of diagnosis for mCSPC patients, considering it is the first step of tailoring individualized treatment. In addition, DNA repair genes were a good therapeutic target for poly (ADP-ribose) polymerase inhibitors, and our results call for more frontline targeted therapy trials in gDDRm carriers to prolong the progression time. Results of this study suggested that positive germline DNA damage repair gene mutation (gDDRm) status predicted earlier progression to castration resistance in patients with de novo metastatic and castration-sensitive prostate cancer (mCSPC). These findings indicated the importance of intense therapy for some subgroups of mCSPC, especially for mCSPC harboring gDDRm with low-volume disease. Moreover, gDDRm was a good therapeutic target for poly (ADP-ribose) polymerase inhibitors, and these findings call for more molecular marker driven trials moving to the mTNPC setting.

Pathogenic Germline DNA Repair Gene and HOXB13 Mutations in Men With Metastatic Prostate Cancer.

Germline mutations in DNA repair (DR) genes and susceptibility genes CDKN2A and HOXB13 have previously been associated with prostate cancer (PC) incidence and/or progression. However, the role and prevalence of this class of mutations in metastatic PC (mPC) are not fully understood. To evaluate the frequency of pathogenic/likely pathogenic germline variants (PVs/LPVs) in men with mPC, this study sequenced 38 DR genes, CDKN2A, and HOXB13 in a predominantly white cohort of 317 patients with mPC. A PC registry at the University of Utah was used for patient sample acquisition and retrospective clinical data collection. Deep target sequencing allowed for germline and copy number variant analyses. Validated PVs/LPVs were integrated with clinical and demographic data for statistical correlation analyses. All pathogenic variants were found in men self-reported as white, with a carrier frequency of 8.5% (DR genes, 7.3%; CDKN2A/HOXB13, 1.2%). Consistent with previous reports, mutations were most frequently identified in the breast cancer susceptibility gene BRCA2. It was also found that 50% of identified PVs/LPVs were categorized as founder mutations with European origins. Correlation analyses did not support a trend toward more advanced or earlier-onset disease in comparisons between carriers and noncarriers of deleterious DR or HOXB13 G84E mutations. These findings demonstrate a lower prevalence of germline PVs/LPVs in an unselected, predominantly white mPC cohort than previously reported, which may have implications for the design of clinical trials testing targeted therapies. Larger studies in broad and diverse populations are needed to more accurately define the prevalence of germline mutations in men with mPC.

Inherited DNA-repair gene mutations in African American men with prostate cancer.

African American men with prostate cancer are understudied relative to Caucasians with prostate cancer with regard to testing for pathogenic germline DNA repair gene mutations. Herein we evaluate these two populations in a large commercial dataset and compare the detection of pathogenic/likely pathogenic alterations in 14 well annotated DNA repair genes (BRCA2, BRCA1, PALB2, ATM, RAD51C, CHEK2, PMS2, BARD1, BRIP1, MLH1, MSH2, MSH6, NBN, and RAD51D). Overall, pathogenic or likely pathogenic alterations in these 14 DNA repair genes were less likely to be detected in African Americans as compared to Caucasians. Upon a more in-depth analysis, the risk of germline pathogenic/likely pathogenic BRCA mutations was similar between the two populations whereas there was a lower risk among African Americans for the non-BRCA mutations. No African American men were noted to have mutations in BARD1, BRIP1, MLH1, MSH2, MSH6, NBN, and RAD51D in this data set. Stage, grade, and metastatic status were not assessed in this group of patients. Larger and more detailed studies conducted in men with prostate cancer are required to confirm these findings.

Abstract 1730: DACH1 gene deletion extends portraits of human prostate cancer

Abstract Purpose of the study: This study was conducted to define the role of Dachshund in prostate cancer, through assessing human prostate cancer samples and through genetic deletion in the mouse. Prostate cancer (PCa), the second leading cause of death in American men, is a genetically heterogeneous disease, likely representing distinct genetic drivers, with terminal events caused primarily by metastasis. Substratification of PCa into genetic subtypes, forms the basis of rational therapy for PCa. A better molecular understanding of the disease is necessary in order to develop novel targeted therapies of metastatic PCa. Known genetic drivers to tumor initiation include PTEN and NKX3.1 deletions, rearrangements of the TMPRSS2 gene to the oncogenic ETS transcription factor, ERG, and genetic predisposing factors include germline DNA-repair gene mutations. The DACH1 gene, initially cloned as an inhibitor of Elipse, the hyperactive epidermal growth factor (EGFR) in Drosophila, was found to be reduced in abundance in several malignancies including breast and prostate cancer. Results: In order to determine whether the DACH1 gene is deleted or mutated in prostate cancer we interrogated the genomic sequencing analysis of over 490 patients from 5 population cohorts. Homozygous deletion of DACH1 was identified in 18% (N=61), 11% (N=136), 10% (N=492), 7% (N=103) and 3% (N=150) of prostate cancer in 5 distinct cohorts. The prevalence of DACH1 gene deep deletions was higher in the metastasis than in the primary tumors. The Transgenic Adenocarcinoma Mouse Prostate (TRAMP) transgenic, Dach1fl/fl, and Probasin-Cre, ROSA26mT/mG transgenic mice were used to generate a prostate epithelial cell specific Dach1 gene knockout mouse (Probasin-Cre-Dach1fl/fl ROSA26mT/mG-TRAMP) lines. Prostate specific deletion of the murine Dach1 gene enhanced progression of prostatic intraepithelial neoplasia (PIN), associated with increased prostate epithelial cell proliferation, epithelial mesenchymal transition (EMT), DNA damage and inflammation. Conclusions: DACH1 gene deletion may define a distinct subclass of prostate cancer that may benefit from PARP inhibitors, and platinum-based chemotherapy. Citation Format: Xuanmao Jiao, Gabriele Di Sante, Zhiping Li, Agnese Di Rocco, Min Wang, Adam Ertel, Peter A. McCue, Andrew P. South, Carlos Cordon-Cardo, Matthew P. Stokes, Marco Marra, Steven J. Jones, Andrew Kossenkov, Richard G. Pestell. DACH1 gene deletion extends portraits of human prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1730.

Germline DNA Repair Gene Mutations in Young-onset Prostate Cancer Cases in the UK: Evidence for a More Extensive Genetic Panel

BackgroundRare germline mutations in DNA repair genes are associated with prostate cancer (PCa) predisposition and prognosis. ObjectiveTo quantify the frequency of germline DNA repair gene mutations in UK PCa cases and controls, in order to more comprehensively evaluate the contribution of individual genes to overall PCa risk and likelihood of aggressive disease. Design, setting, and participantsWe sequenced 167 DNA repair and eight PCa candidate genes in a UK-based cohort of 1281 young-onset PCa cases (diagnosed at ≤60yr) and 1160 selected controls. Outcome measurements and statistical analysisGene-level SKAT-O and gene-set adaptive combination of p values (ADA) analyses were performed separately for cases versus controls, and aggressive (Gleason score ≥8, n=201) versus nonaggressive (Gleason score ≤7, n=1048) cases. Results and limitationsWe identified 233 unique protein truncating variants (PTVs) with minor allele frequency <0.5% in controls in 97 genes. The total proportion of PTV carriers was higher in cases than in controls (15% vs 12%, odds ratio [OR]=1.29, 95% confidence interval [CI] 1.01–1.64, p=0.036). Gene-level analyses selected NBN (pSKAT-O=2.4×10−4) for overall risk and XPC (pSKAT-O=1.6×10−4) for aggressive disease, both at candidate-level significance (p<3.1×10−4 and p<3.4×10−4, respectively). Gene-set analysis identified a subset of 20 genes associated with increased PCa risk (OR=3.2, 95% CI 2.1–4.8, pADA=4.1×10−3) and four genes that increased risk of aggressive disease (OR=11.2, 95% CI 4.6–27.7, pADA=5.6×10−3), three of which overlap the predisposition gene set. ConclusionsThe union of the gene-level and gene-set-level analyses identified 23 unique DNA repair genes associated with PCa predisposition or risk of aggressive disease. These findings will help facilitate the development of a PCa-specific sequencing panel with both predictive and prognostic potential. Patient summaryThis large sequencing study assessed the rate of inherited DNA repair gene mutations between prostate cancer patients and disease-free men. A panel of 23 genes was identified, which may improve risk prediction or treatment pathways in future clinical practice.