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Yu Z, Coorens THH, Uddin MM, Ardlie KG, Lennon N, Natarajan P. Genetic variation across and within individuals. Nat Rev Genet 2024:10.1038/s41576-024-00709-x. [PMID: 38548833 DOI: 10.1038/s41576-024-00709-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2024] [Indexed: 04/12/2024]
Abstract
Germline variation and somatic mutation are intricately connected and together shape human traits and disease risks. Germline variants are present from conception, but they vary between individuals and accumulate over generations. By contrast, somatic mutations accumulate throughout life in a mosaic manner within an individual due to intrinsic and extrinsic sources of mutations and selection pressures acting on cells. Recent advancements, such as improved detection methods and increased resources for association studies, have drastically expanded our ability to investigate germline and somatic genetic variation and compare underlying mutational processes. A better understanding of the similarities and differences in the types, rates and patterns of germline and somatic variants, as well as their interplay, will help elucidate the mechanisms underlying their distinct yet interlinked roles in human health and biology.
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Affiliation(s)
- Zhi Yu
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Cardiovascular Research Center and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | | | - Md Mesbah Uddin
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Cardiovascular Research Center and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | | | - Niall Lennon
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Pradeep Natarajan
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Cardiovascular Research Center and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA.
- Department of Medicine, Harvard Medical School, Boston, MA, USA.
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2
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Meijer TG, Martens JWM, Prager-van der Smissen WJC, Verkaik NS, Beaufort CM, van Herk S, Robert-Finestra T, Hoogenboezem RM, Ruigrok-Ritstier K, Paul MW, Gribnau J, Bindels EMJ, Kanaar R, Jager A, van Gent DC, Hollestelle A. Functional Homologous Recombination (HR) Screening Shows the Majority of BRCA1/2-Mutant Breast and Ovarian Cancer Cell Lines Are HR-Proficient. Cancers (Basel) 2024; 16:741. [PMID: 38398132 PMCID: PMC10887177 DOI: 10.3390/cancers16040741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 01/30/2024] [Accepted: 02/08/2024] [Indexed: 02/25/2024] Open
Abstract
Tumors with a pathogenic BRCA1/2 mutation are homologous recombination (HR)-deficient (HRD) and consequently sensitive to platinum-based chemotherapy and Poly-[ADP-Ribose]-Polymerase inhibitors (PARPi). We hypothesized that functional HR status better reflects real-time HR status than BRCA1/2 mutation status. Therefore, we determined the functional HR status of 53 breast cancer (BC) and 38 ovarian cancer (OC) cell lines by measuring the formation of RAD51 foci after irradiation. Discrepancies between functional HR and BRCA1/2 mutation status were investigated using exome sequencing, methylation and gene expression data from 50 HR-related genes. A pathogenic BRCA1/2 mutation was found in 10/53 (18.9%) of BC and 7/38 (18.4%) of OC cell lines. Among BRCA1/2-mutant cell lines, 14/17 (82.4%) were HR-proficient (HRP), while 1/74 (1.4%) wild-type cell lines was HRD. For most (80%) cell lines, we explained the discrepancy between functional HR and BRCA1/2 mutation status. Importantly, 12/14 (85.7%) BRCA1/2-mutant HRP cell lines were explained by mechanisms directly acting on BRCA1/2. Finally, functional HR status was strongly associated with COSMIC single base substitution signature 3, but not BRCA1/2 mutation status. Thus, the majority of BRCA1/2-mutant cell lines do not represent a suitable model for HRD. Moreover, exclusively determining BRCA1/2 mutation status may not suffice for platinum-based chemotherapy or PARPi patient selection.
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Affiliation(s)
- Titia G Meijer
- Department of Molecular Genetics, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
- Department of Pathology, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
- Oncode Institute, 3521 AL Utrecht, The Netherlands
| | - John W M Martens
- Department of Medical Oncology, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Wendy J C Prager-van der Smissen
- Department of Medical Oncology, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Nicole S Verkaik
- Department of Molecular Genetics, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
- Oncode Institute, 3521 AL Utrecht, The Netherlands
| | - Corine M Beaufort
- Department of Medical Oncology, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Stanley van Herk
- Oncode Institute, 3521 AL Utrecht, The Netherlands
- Department of Hematology, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Teresa Robert-Finestra
- Oncode Institute, 3521 AL Utrecht, The Netherlands
- Department of Developmental Biology, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Remco M Hoogenboezem
- Department of Hematology, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Kirsten Ruigrok-Ritstier
- Department of Medical Oncology, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Maarten W Paul
- Department of Molecular Genetics, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
- Oncode Institute, 3521 AL Utrecht, The Netherlands
| | - Joost Gribnau
- Oncode Institute, 3521 AL Utrecht, The Netherlands
- Department of Developmental Biology, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Eric M J Bindels
- Department of Hematology, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Roland Kanaar
- Department of Molecular Genetics, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
- Oncode Institute, 3521 AL Utrecht, The Netherlands
| | - Agnes Jager
- Department of Medical Oncology, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Dik C van Gent
- Department of Molecular Genetics, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
- Oncode Institute, 3521 AL Utrecht, The Netherlands
| | - Antoinette Hollestelle
- Department of Medical Oncology, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands
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3
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Brown TJ, Yablonovitch A, Till JE, Yen J, Kiedrowski LA, Hood R, O'Hara MH, Teitelbaum U, Karasic TB, Schneider C, Carpenter EL, Nathanson K, Domchek SM, Reiss KA. The Clinical Implications of Reversions in Patients with Advanced Pancreatic Cancer and Pathogenic Variants in BRCA1, BRCA2, or PALB2 after Progression on Rucaparib. Clin Cancer Res 2023; 29:5207-5216. [PMID: 37486343 PMCID: PMC10806928 DOI: 10.1158/1078-0432.ccr-23-1467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/13/2023] [Accepted: 07/20/2023] [Indexed: 07/25/2023]
Abstract
PURPOSE PARP inhibitors (PARPi) provide an effective maintenance option for patients with BRCA- or PALB2-mutated pancreatic cancer. However, mechanisms of PARPi resistance and optimal post-PARPi therapeutic strategies are poorly characterized. EXPERIMENTAL DESIGN We collected paired cell-free DNA samples and post-PARPi clinical data on 42 patients with advanced, platinum-sensitive pancreatic cancer who were treated with maintenance rucaparib on NCT03140670, of whom 32 developed progressive disease. RESULTS Peripherally detected, acquired BRCA or PALB2 reversion variants were uncommon (5/30; 16.6%) in patients who progressed on rucaparib. Reversions were significantly associated with rapid resistance to PARPi treatment (median PFS, 3.7 vs. 12.5 months; P = 0.001) and poor overall survival (median OS, 6.2 vs. 23.0 months; P < 0.0001). All patients with reversions received rechallenge with platinum-based chemotherapy following PARPi progression and experienced faster progression on this therapy than those without reversion variants (real-world time-to-treatment discontinuation, 2.4 vs. 5.8 months; P = 0.004). Of the patients who progressed on PARPi and received further chemotherapy, the OS from initiation of second-line therapy was significantly lower in those with reversion variants than in those without (5.5 vs. 12.0 months, P = 0.002). Finally, high levels of tumor shedding were independently associated with poor outcomes in patients who received rucaparib. CONCLUSIONS Acquired reversion variants were uncommon but detrimental in a population of patients with advanced BRCA- or PALB2-related pancreatic ductal adenocarcinoma who received maintenance rucaparib. Reversion variants led to rapid progression on PARPi, rapid failure of subsequent platinum-based treatment, and poor OS of patients. The identification of such variants in the blood may have both predictive and prognostic value. See related commentary by Tsang and Gallinger, p. 5005.
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Affiliation(s)
- Timothy J Brown
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
- Penn Center for Cancer Care Innovation, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Jacob E Till
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | | | - Ryan Hood
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Mark H O'Hara
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ursina Teitelbaum
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Thomas B Karasic
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Charles Schneider
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Erica L Carpenter
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Katherine Nathanson
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Susan M Domchek
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kim A Reiss
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
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Keane F, Bajwa R, Selenica P, Park W, Roehrl MH, Reis-Filho JS, Mandelker D, O'Reilly EM. Dramatic, durable response to therapy in gBRCA2-mutated pancreas neuroendocrine carcinoma: opportunity and challenge. NPJ Precis Oncol 2023; 7:40. [PMID: 37087482 PMCID: PMC10122663 DOI: 10.1038/s41698-023-00376-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 03/30/2023] [Indexed: 04/24/2023] Open
Abstract
Poorly differentiated pancreatic neuroendocrine tumors (PDNEC), are a subtype of pancreatic cancer encompassing both small cell and large cell neuroendocrine carcinoma subtypes, and are characterized as distinct in terms of biology and prognosis compared to the more common pancreatic adenocarcinoma. Until recently, there has been a paucity of data on the genomic features of this cancer type. We describe a male patient diagnosed with PDNEC and extensive metastatic disease in the liver at diagnosis. Genomic analysis demonstrated a germline pathogenic variant in BRCA2 with somatic loss-of-heterozygosity of the BRCA2 wild-type allele. Following a favorable response to platinum-based chemotherapy (and the addition of immunotherapy), the patient received maintenance therapy with olaparib, which resulted in a further reduction on follow-up imaging (Fig. 1). After seventeen months of systemic control with olaparib, the patient developed symptomatic central nervous system metastases, which harboured a BRCA2 reversion mutation. No other sites of disease progression were observed. Herein, we report an exceptional outcome through the incorporation of a personalized management approach for a patient with a pancreatic PDNEC, guided by comprehensive genomic sequencing.
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Affiliation(s)
- Fergus Keane
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- David M. Rubenstein Center for Pancreatic Cancer Research, New York, NY, USA
| | - Raazi Bajwa
- David M. Rubenstein Center for Pancreatic Cancer Research, New York, NY, USA
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Pier Selenica
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Wungki Park
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- David M. Rubenstein Center for Pancreatic Cancer Research, New York, NY, USA
- Department of Medicine, Weill Cornell Medical College, New York, NY, USA
- Parker Institute for Cancer Immunotherapy, San Francisco, CA, USA
| | - Michael H Roehrl
- David M. Rubenstein Center for Pancreatic Cancer Research, New York, NY, USA
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jorge S Reis-Filho
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Diana Mandelker
- David M. Rubenstein Center for Pancreatic Cancer Research, New York, NY, USA
- Parker Institute for Cancer Immunotherapy, San Francisco, CA, USA
- Diagnostic Molecular Genetics Laboratory, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Eileen M O'Reilly
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- David M. Rubenstein Center for Pancreatic Cancer Research, New York, NY, USA.
- Department of Medicine, Weill Cornell Medical College, New York, NY, USA.
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5
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Analysis of matched primary and recurrent BRCA1/2 mutation-associated tumors identifies recurrence-specific drivers. Nat Commun 2022; 13:6728. [PMID: 36344544 PMCID: PMC9640723 DOI: 10.1038/s41467-022-34523-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 10/27/2022] [Indexed: 11/09/2022] Open
Abstract
Recurrence is a major cause of death among BRCA1/2 mutation carriers with breast (BrCa) and ovarian cancers (OvCa). Herein we perform multi-omic sequencing on 67 paired primary and recurrent BrCa and OvCa from 27 BRCA1/2 mutation carriers to identify potential recurrence-specific drivers. PARP1 amplifications are identified in recurrences (False Discovery Rate q = 0.05), and PARP1 is significantly overexpressed across primary BrCa and recurrent BrCa and OvCa, independent of amplification status. RNA sequencing analysis finds two BRCA2 isoforms, BRCA2-201/Long and BRCA2-001/Short, respectively predicted to be sensitive and insensitive to nonsense-mediated decay. BRCA2-001/Short is expressed more frequently in recurrences and associated with reduced overall survival in breast cancer (87 vs. 121 months; Hazard Ratio = 2.5 [1.18-5.5]). Loss of heterozygosity (LOH) status is discordant in 25% of patient's primary and recurrent tumors, with switching between both LOH and lack of LOH found. Our study reveals multiple potential drivers of recurrent disease in BRCA1/2 mutation-associated cancer, improving our understanding of tumor evolution and suggesting potential biomarkers.
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Gallardo-Rincón D, Montes-Servín E, Alamilla-García G, Montes-Servín E, Bahena-González A, Cetina-Pérez L, Morales Vásquez F, Cano-Blanco C, Coronel-Martínez J, González-Ibarra E, Espinosa-Romero R, María Alvarez-Gómez R, Pedroza-Torres A, Castro-Eguiluz D. Clinical Benefits of Olaparib in Mexican Ovarian Cancer Patients With Founder Mutation BRCA1-Del ex9-12. Front Genet 2022; 13:863956. [PMID: 35734436 PMCID: PMC9207274 DOI: 10.3389/fgene.2022.863956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 05/02/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Ovarian cancer (OC) is gynecologic cancer with the highest mortality rate. It is estimated that 13–17% of ovarian cancers are due to heritable mutations in BRCA1 and BRCA2. The BRCA1 (BRCA1-Del ex9-12) Mexican founder mutation is responsible for 28–35% of the cases with ovarian cancer. The aim was to describe the PFS of OC patients treated with olaparib, emphasizing patients carrying the Mexican founder mutation (BRCA1-Del ex9-12). Methods: In this observational study, of 107 patients with BRCAm, 35 patients were treated with olaparib from November 2016 to May 2021 at the Ovarian Cancer Program (COE) of Mexico; patient information was extracted from electronic medical records. Results: Of 311 patients, 107 (34.4%) were with BRCAm; 71.9% (77/107) were with BRCA1, of which 27.3% (21/77) were with BRCA1-Del ex9-12, and 28.1% (30/107) were with BRCA2 mutations. Only 35 patients received olaparib treatment, and the median follow-up was 12.87 months. The PFS of BRCA1-Del ex9-12 was NR (non-reach); however, 73% of the patients received the treatment at 36 vs. 11.59 months (95% CI; 10.43–12.75) in patients with other BRCAm (p = 0.008). Almost 50% of patients required dose reduction due to toxicity; the most frequent adverse events were hematological in 76.5% and gastrointestinal in 4%. Conclusion: Mexican OC BRCA1-Del ex9-12 patients treated with olaparib had a significant increase in PFS regardless of the line of treatment compared to other mutations in BRCA.
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Affiliation(s)
- Dolores Gallardo-Rincón
- Ovarian and Endometrial Cancer Program (COE), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Department of Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- *Correspondence: Dolores Gallardo-Rincón,
| | - Edgar Montes-Servín
- Ovarian and Endometrial Cancer Program (COE), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Gabriela Alamilla-García
- Ovarian and Endometrial Cancer Program (COE), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Department of Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Elizabeth Montes-Servín
- Ovarian and Endometrial Cancer Program (COE), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Antonio Bahena-González
- Ovarian and Endometrial Cancer Program (COE), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Department of Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Lucely Cetina-Pérez
- Department of Clinical Research and Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Cervical Cancer Program (Micaela), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Flavia Morales Vásquez
- Department of Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Claudia Cano-Blanco
- Department of Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Jaime Coronel-Martínez
- Department of Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Ernesto González-Ibarra
- Ovarian and Endometrial Cancer Program (COE), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Raquel Espinosa-Romero
- Ovarian and Endometrial Cancer Program (COE), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Department of Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Rosa María Alvarez-Gómez
- Department of Clinical Research and Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Hereditary Cancer Clinic, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Abraham Pedroza-Torres
- Hereditary Cancer Clinic, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Catedrático CONACYT, Instituto Nacional de Cancerología, Mexico City, Mexico
| | - Denisse Castro-Eguiluz
- Cervical Cancer Program (Micaela), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Catedrático CONACYT, Instituto Nacional de Cancerología, Mexico City, Mexico
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Sorrells S, McKinnon KE, McBratney A, Sumey C. Longitudinal and multi-tissue molecular diagnostics track somatic BRCA2 reversion mutations that correct the open reading frame of germline alteration upon clinical relapse. NPJ Genom Med 2021; 6:17. [PMID: 33619265 PMCID: PMC7900170 DOI: 10.1038/s41525-021-00181-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 01/12/2021] [Indexed: 12/28/2022] Open
Abstract
BRCA-mutant cancers often develop therapeutic resistance through several mechanisms. Here, we report a case of pathogenic germline BRCA2-driven breast cancer monitored for disease progression and acquired resistance using longitudinal multi-tissue genomic testing. Briefly, genomic testing was performed throughout the course of disease on tumor tissue from multiple sites, circulating tumor DNA from blood plasma, and matched normal tissue. Genomic analyses identified actionable variants for targeted therapies, as well as emerging resistance mutations over time. Two unique BRCA2 somatic alterations (p.N255fs and p.D252fs) were identified upon resistance to PARP inhibitor and platinum treatment, respectively. Both alterations restored the open reading frame of the original germline alteration, likely accounting for acquired resistance. This case exemplifies the evolution of multiple subclonal BRCA reversion alterations over time and demonstrates the value of longitudinal multi-tissue genomic testing for monitoring disease progression, predicting measures of response, and evaluating treatment outcomes in oncology patients.
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Khalique S, Pettitt SJ, Kelly G, Tunariu N, Natrajan R, Banerjee S, Lord CJ. Longitudinal analysis of a secondary BRCA2 mutation using digital droplet PCR. J Pathol Clin Res 2020; 6:3-11. [PMID: 31577852 PMCID: PMC6966703 DOI: 10.1002/cjp2.146] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/13/2019] [Accepted: 09/16/2019] [Indexed: 01/31/2023]
Abstract
Development of resistance to platinum and poly(ADP-ribose) polymerase inhibitors via secondary BRCA gene mutations that restore functional homologous recombination has been observed in a number of cancer types. Here we report a case of somatic BRCA2 mutation in a patient with high grade serous ovarian carcinoma. A secondary mutation predicted to restore the BRCA2 open reading frame was detected at low frequency (2.3%) in whole exome sequencing of a peritoneal biopsy at disease progression after treatment that included carboplatin and olaparib. We used digital droplet PCR (ddPCR) to verify the presence and frequency of this mutation in the biopsy sample at progression and also used this approach to assess the presence of the secondary mutation in preceding biopsies at diagnosis and first relapse. We found no evidence for the secondary mutation being present prior to the final progression biopsy, suggesting that this mutation was acquired late in the course of treatment. ddPCR provides a sensitive and specific technique to investigate the presence of low frequency mutations in a time series of biopsies.
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Affiliation(s)
- Saira Khalique
- Division of Molecular PathologyThe Institute of Cancer ResearchLondonUK
- The Breast Cancer Now Toby Robins Research CentreThe Institute of Cancer ResearchLondonUK
- The Royal Marsden NHS Foundation Trust and The Institute of Cancer ResearchSuttonUK
| | - Stephen J Pettitt
- The CRUK Gene Function Laboratory and Breast Cancer Now Research CentreThe Institute of Cancer ResearchLondonUK
| | - Ger Kelly
- The CRUK Gene Function Laboratory and Breast Cancer Now Research CentreThe Institute of Cancer ResearchLondonUK
| | - Nina Tunariu
- The Royal Marsden NHS Foundation Trust and The Institute of Cancer ResearchSuttonUK
| | - Rachael Natrajan
- Division of Molecular PathologyThe Institute of Cancer ResearchLondonUK
| | - Susana Banerjee
- The Royal Marsden NHS Foundation Trust and The Institute of Cancer ResearchSuttonUK
| | - Christopher J Lord
- The CRUK Gene Function Laboratory and Breast Cancer Now Research CentreThe Institute of Cancer ResearchLondonUK
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9
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Laera L, Guaragnella N, Giannattasio S, Moro L. 6-Thioguanine and Its Analogs Promote Apoptosis of Castration-Resistant Prostate Cancer Cells in a BRCA2-Dependent Manner. Cancers (Basel) 2019; 11:E945. [PMID: 31284411 PMCID: PMC6678799 DOI: 10.3390/cancers11070945] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 07/03/2019] [Indexed: 12/27/2022] Open
Abstract
Background: Mutations in the oncosuppressor gene BReast CAncer susceptibility gene 2 (BRCA2) predispose to aggressive forms of prostate cancer which show poor response to taxane-based therapy, the standard treatment for castration-resistant, aggressive prostate cancer. Herein, we addressed the question whether changes in BRCA2 expression, a potential surrogate marker for BRCA2 activity, may affect the response of castration-resistant prostate cancer cells to 6-thioguanine (6-TG), a thiopurine used in the treatment of haematological malignancies. Methods: Yeast, normal prostate cells and castration-resistant prostate cancer cells were treated with 6-TG or its analogues, in presence or absence of paclitaxel, or with olaparib, a poly-(ADP-ribose) polymerase (PARP) inhibitor currently in clinical trials for treatment of metastatic castration-resistant prostate cancer, and cell proliferation, apoptosis and androgen receptor (AR) levels were measured. Results: 6-TG inhibited cell proliferation in yeast, normal and castration-resistant prostate cancer cells but promoted apoptosis only in cancer cells. Suppression of BRCA2 expression by siRNA or shRNA increased the sensitivity to 6-TG- and olaparib-induced apoptosis but did not affect cancer cell response to taxane. Intriguingly, 6-TG reduced AR expression levels independently on BRCA2 expression. Instead, olaparib decreased AR levels only in BRCA2-knockdown prostate cancer cells. Notably, overexpression of BRCA2 resulted in resistance of castration-resistant prostate cancer cells to 6-TG-, taxane- and olaparib-based treatment but promoted sensitivity to apoptosis induced by 2-amino-6-bromopurine and 2,6-dithiopurine, two 6-TG analogues. Conclusions: Our results provide a pre-clinical rationale for the use of 6-TG in the treatment of BRCA2-deficient castration-resistant prostate cancers, and of certain 6-TG analogues for treatment of BRCA2-proficient prostate cancers.
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Affiliation(s)
- Luna Laera
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, National Research Council, Via Amendola 122/O, 70126 Bari, Italy
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy
| | - Nicoletta Guaragnella
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, National Research Council, Via Amendola 122/O, 70126 Bari, Italy
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy
| | - Sergio Giannattasio
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, National Research Council, Via Amendola 122/O, 70126 Bari, Italy
| | - Loredana Moro
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, National Research Council, Via Amendola 122/O, 70126 Bari, Italy.
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