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Ustun Yilmaz S, Agaoglu NB, Manto K, Muftuoglu M, Özbek U. Cosmic Whirl: Navigating the Comet Trail in DNA: H2AX Phosphorylation and the Enigma of Uncertain Significance Variants. Genes (Basel) 2024; 15:724. [PMID: 38927659 PMCID: PMC11202575 DOI: 10.3390/genes15060724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/15/2024] [Accepted: 05/23/2024] [Indexed: 06/28/2024] Open
Abstract
Pathogenic variations in the BRCA2 gene have been detected with the development of next-generation sequencing (NGS)-based hereditary cancer panel testing technology. It also reveals an increasing number of variants of uncertain significance (VUSs). Well-established functional tests are crucial to accurately reclassifying VUSs for effective diagnosis and treatment. We retrospectively analyzed the multi-gene cancer panel results of 922 individuals and performed in silico analysis following ClinVar classification. Then, we selected five breast cancer-diagnosed patients' missense BRCA2 VUSs (T1011R, T1104P/M1168K, R2027K, G2044A, and D2819) for reclassification. The effects of VUSs on BRCA2 function were analyzed using comet and H2AX phosphorylation (γH2AX) assays before and after the treatment of peripheral blood mononuclear cells (PBMCs) of subjects with the double-strand break (DSB) agent doxorubicin (Dox). Before and after Dox-induction, the amount of DNA in the comet tails was similar in VUS carriers; however, notable variations in γH2AX were observed, and according to combined computational and functional analyses, we reclassified T1001R as VUS-intermediate, T1104P/M1168K and D2819V as VUS (+), and R2027K and G2044A as likely benign. These findings highlight the importance of the variability of VUSs in response to DNA damage before and after Dox-induction and suggest that further investigation is needed to understand the underlying mechanisms.
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Affiliation(s)
- Sevdican Ustun Yilmaz
- Department of Medical Biotechnology, Institute of Health Sciences, Acibadem Mehmet Ali Aydinlar University, 34752 Istanbul, Türkiye; (S.U.Y.); (M.M.)
| | - Nihat Bugra Agaoglu
- Department of Medical Genetics, Umraniye Training and Research Hospital, University of Health Sciences, 34764 Istanbul, Türkiye;
- IKF-The Frankfurt Institute of Clinical Cancer Research, 60488 Frankfurt am Main, Germany
| | - Karin Manto
- Department of Genome Studies, Institute of Health Sciences, Acibadem Mehmet Ali Aydinlar University, 34752 Istanbul, Türkiye;
| | - Meltem Muftuoglu
- Department of Medical Biotechnology, Institute of Health Sciences, Acibadem Mehmet Ali Aydinlar University, 34752 Istanbul, Türkiye; (S.U.Y.); (M.M.)
- Department of Molecular Biology and Genetics, Faculty of Engineering and Natural Sciences, Acibadem Mehmet Ali Aydinlar University, 34752 Istanbul, Türkiye
| | - Ugur Özbek
- Department of Medical Biotechnology, Institute of Health Sciences, Acibadem Mehmet Ali Aydinlar University, 34752 Istanbul, Türkiye; (S.U.Y.); (M.M.)
- Department of Genome Studies, Institute of Health Sciences, Acibadem Mehmet Ali Aydinlar University, 34752 Istanbul, Türkiye;
- Izmir Biomedicine and Genome Center (IBG), 35340 Izmir, Türkiye
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2
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Jimenez-Sainz J, Jensen RB. Imprecise Medicine: BRCA2 Variants of Uncertain Significance (VUS), the Challenges and Benefits to Integrate a Functional Assay Workflow with Clinical Decision Rules. Genes (Basel) 2021; 12:genes12050780. [PMID: 34065235 PMCID: PMC8161351 DOI: 10.3390/genes12050780] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 12/20/2022] Open
Abstract
Pathological mutations in homology-directed repair (HDR) genes impact both future cancer risk and therapeutic options for patients. HDR is a high-fidelity DNA repair pathway for resolving DNA double-strand breaks throughout the genome. BRCA2 is an essential protein that mediates the loading of RAD51 onto resected DNA breaks, a key step in HDR. Germline mutations in BRCA2 are associated with an increased risk for breast, ovarian, prostate, and pancreatic cancer. Clinical findings of germline or somatic BRCA2 mutations in tumors suggest treatment with platinum agents or PARP inhibitors. However, when genetic analysis reveals a variant of uncertain significance (VUS) in the BRCA2 gene, precision medicine-based decisions become complex. VUS are genetic changes with unknown pathological impact. Current statistics indicate that between 10–20% of BRCA sequencing results are VUS, and of these, more than 50% are missense mutations. Functional assays to determine the pathological outcome of VUS are urgently needed to provide clinical guidance regarding cancer risk and treatment options. In this review, we provide a brief overview of BRCA2 functions in HDR, describe how BRCA2 VUS are currently assessed in the clinic, and how genetic and biochemical functional assays could be integrated into the clinical decision process. We suggest a multi-step workflow composed of robust and accurate functional assays to correctly evaluate the potential pathogenic or benign nature of BRCA2 VUS. Success in this precision medicine endeavor will offer actionable information to patients and their physicians.
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Affiliation(s)
- Judit Jimenez-Sainz
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Correspondence: (J.J.-S.); (R.B.J.); Tel.:+1-203-737-6456 (R.B.J.)
| | - Ryan B. Jensen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA
- Correspondence: (J.J.-S.); (R.B.J.); Tel.:+1-203-737-6456 (R.B.J.)
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3
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Sullivan T, Thirthagiri E, Chong CE, Stauffer S, Reid S, Southon E, Hassan T, Ravichandran A, Wijaya E, Lim J, Taib NAM, Fadzli F, Yip CH, Hartman M, Li J, van Dam RM, North SL, Das R, Easton DF, Biswas K, Teo SH, Sharan SK. Epidemiological and ES cell-based functional evaluation of BRCA2 variants identified in families with breast cancer. Hum Mutat 2021; 42:200-212. [PMID: 33314489 PMCID: PMC7919386 DOI: 10.1002/humu.24154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 09/29/2020] [Accepted: 11/28/2020] [Indexed: 01/06/2023]
Abstract
The discovery of high-risk breast cancer susceptibility genes, such as Breast cancer associated gene 1 (BRCA1) and Breast cancer associated gene 2 (BRCA2) has led to accurate identification of individuals for risk management and targeted therapy. The rapid decline in sequencing costs has tremendously increased the number of individuals who are undergoing genetic testing world-wide. However, given the significant differences in population-specific variants, interpreting the results of these tests can be challenging especially for novel genetic variants in understudied populations. Here we report the characterization of novel variants in the Malaysian and Singaporean population that consist of different ethnic groups (Malays, Chinese, Indian, and other indigenous groups). We have evaluated the functional significance of 14 BRCA2 variants of uncertain clinical significance by using multiple in silico prediction tools and examined their frequency in a cohort of 7840 breast cancer cases and 7928 healthy controls. In addition, we have used a mouse embryonic stem cell (mESC)-based functional assay to assess the impact of these variants on BRCA2 function. We found these variants to be functionally indistinguishable from wild-type BRCA2. These variants could fully rescue the lethality of Brca2-null mESCs and exhibited no sensitivity to six different DNA damaging agents including a poly ADP ribose polymerase inhibitor. Our findings strongly suggest that all 14 evaluated variants are functionally neutral. Our findings should be valuable in risk assessment of individuals carrying these variants.
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Affiliation(s)
- Teresa Sullivan
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Eswary Thirthagiri
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.,Servier, Kuala Lumpur, Malaysia.,Cancer Research Malaysia, Subang Jaya, Selangor, Malaysia
| | - Chan-Eng Chong
- Cancer Research Malaysia, Subang Jaya, Selangor, Malaysia
| | - Stacey Stauffer
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Susan Reid
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Eileen Southon
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Tiara Hassan
- Cancer Research Malaysia, Subang Jaya, Selangor, Malaysia
| | - Aravind Ravichandran
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India.,SASTRA University, Thirumalaisamudram, Thanjavur, Tamil Nadu, India
| | | | - Joanna Lim
- Cancer Research Malaysia, Subang Jaya, Selangor, Malaysia
| | - Nur Aishah Mohd Taib
- Breast Cancer Research Unit, UM Cancer Research Institute, University of Malaya Medical Center, Kuala Lumpur, Malaysia
| | - Farhana Fadzli
- Breast Cancer Research Unit, UM Cancer Research Institute, University of Malaya Medical Center, Kuala Lumpur, Malaysia
| | | | - Mikael Hartman
- Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore.,Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore
| | - Jingmei Li
- Genome Institute of Singapore, Human Genetics, Singapore, Singapore.,Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore
| | - Rob M van Dam
- Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore
| | - Susan L North
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Ranabir Das
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India
| | - Douglas F Easton
- Centre for Cancer Genetic Epidemiology, University of Cambridge, Cambridge, UK
| | - Kajal Biswas
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Soo-Hwang Teo
- Cancer Research Malaysia, Subang Jaya, Selangor, Malaysia.,Breast Cancer Research Unit, UM Cancer Research Institute, University of Malaya Medical Center, Kuala Lumpur, Malaysia
| | - Shyam K Sharan
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
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Mansouri M, Derkaoui T, Bakkach J, Loudiyi A, Ghailani Nourouti N, Barakat A, Villarreal JM, Bringas CC, Bennani Mechita M. Screening of BRCA1 and BRCA2 germline mutations in unselected triple‐negative breast cancer patients: A series from north of Morocco. PRECISION MEDICAL SCIENCES 2020. [DOI: 10.1002/prm2.12009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Mohammed Mansouri
- Laboratory of Biomedical Genomics and Oncogenetics, Faculty of Sciences and Techniques of TangierAbdelmalek Essaâdi University Tetouan Morocco
- Oncology Clinic Al Amal of Tangier Tangier Morocco
| | - Touria Derkaoui
- Laboratory of Biomedical Genomics and Oncogenetics, Faculty of Sciences and Techniques of TangierAbdelmalek Essaâdi University Tetouan Morocco
| | - Joaira Bakkach
- Laboratory of Biomedical Genomics and Oncogenetics, Faculty of Sciences and Techniques of TangierAbdelmalek Essaâdi University Tetouan Morocco
| | - Ali Loudiyi
- Oncology Clinic Al Amal of Tangier Tangier Morocco
| | - Naima Ghailani Nourouti
- Laboratory of Biomedical Genomics and Oncogenetics, Faculty of Sciences and Techniques of TangierAbdelmalek Essaâdi University Tetouan Morocco
| | - Amina Barakat
- Laboratory of Biomedical Genomics and Oncogenetics, Faculty of Sciences and Techniques of TangierAbdelmalek Essaâdi University Tetouan Morocco
| | | | | | - Mohcine Bennani Mechita
- Laboratory of Biomedical Genomics and Oncogenetics, Faculty of Sciences and Techniques of TangierAbdelmalek Essaâdi University Tetouan Morocco
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Consolidated BRCA1/2 Variant Interpretation by MH BRCA Correlates with Predicted PARP Inhibitor Efficacy Association by MH Guide. Int J Mol Sci 2020; 21:ijms21113895. [PMID: 32486089 PMCID: PMC7312854 DOI: 10.3390/ijms21113895] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/20/2020] [Accepted: 05/29/2020] [Indexed: 12/26/2022] Open
Abstract
BRCA1/2 variants are prognostic biomarkers for hereditary breast and/or ovarian cancer (HBOC) syndrome and predictive biomarkers for PARP inhibition. In this study, we benchmarked the classification of BRCA1/2 variants from patients with HBOC-related cancer using MH BRCA, a novel computational technology that combines the ACMG guidelines with expert-curated variant annotations. Evaluation of BRCA1/2 variants (n = 1040) taken from four HBOC studies showed strong concordance within the pathogenic (98.1%) subset. Comparison of MH BRCA’s ACMG classification to ClinVar submitter content from ENIGMA, the international consortium of investigators on the clinical significance of BRCA1/2 variants, the ARUP laboratories, a clinical testing lab of the University of UTAH, and the German Cancer Consortium showed 99.98% concordance (4975 out of 4976 variants) in the pathogenic subset. In our patient cohort, refinement of patients with variants of unknown significance reduced the uncertainty of cancer-predisposing syndromes by 64.7% and identified three cases with potential family risk to HBOC due to a likely pathogenic variant BRCA1 p.V1653L (NM_007294.3:c.4957G > T; rs80357261). To assess whether classification results predict PARP inhibitor efficacy, contextualization with functional impact information on DNA repair activity were performed, using MH Guide. We found a strong correlation between treatment efficacy association and MH BRCA classifications. Importantly, low efficacy to PARP inhibition was predicted in 3.95% of pathogenic variants from four examined HBOC studies and our patient cohort, indicating the clinical relevance of the consolidated variant interpretation.
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6
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High-throughput functional evaluation of BRCA2 variants of unknown significance. Nat Commun 2020; 11:2573. [PMID: 32444794 PMCID: PMC7244490 DOI: 10.1038/s41467-020-16141-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 04/17/2020] [Indexed: 12/14/2022] Open
Abstract
Numerous nontruncating missense variants of the BRCA2 gene have been identified, but there is a lack of convincing evidence, such as familial data, demonstrating their clinical relevance and they thus remain unactionable. To assess the pathogenicity of variants of unknown significance (VUSs) within BRCA2, here we develop a method, the MANO-B method, for high-throughput functional evaluation utilizing BRCA2-deficient cells and poly (ADP-ribose) polymerase (PARP) inhibitors. The estimated sensitivity and specificity of this assay compared to those of the International Agency for Research on Cancer classification system is 95% and 95% (95% confidence intervals: 77–100% and 82–99%), respectively. We classify the functional impact of 186 BRCA2 VUSs with our computational pipeline, resulting in the classification of 126 variants as normal/likely normal, 23 as intermediate, and 37 as abnormal/likely abnormal. We further describe a simplified, on-demand annotation system that could be used as a companion diagnostic for PARP inhibitors in patients with unknown BRCA2 VUSs. Many germline variants are found in the BRCA2 gene, some of which pre-dispose women to breast and ovarian cancer. Here, the authors develop a method to determine the functional significance of BRCA2 variants and show that it is comparable to the IARC system of classifying variants.
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7
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Lodovichi S, Bellè F, Cervelli T, Lorenzoni A, Maresca L, Cozzani C, Caligo MA, Galli A. Effect of BRCA1 missense variants on gene reversion in DNA double-strand break repair mutants and cell cycle-arrested cells of Saccharomyces cerevisiae. Mutagenesis 2019; 35:189-195. [DOI: 10.1093/mutage/gez043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/31/2019] [Indexed: 12/13/2022] Open
Abstract
AbstractEvaluation of the functional impact of germline BRCA1 variants that are likely to be associated to breast and ovarian cancer could help to investigate the mechanism of BRCA1 tumorigenesis. Expression of pathogenic BRCA1 missense variants increased homologous recombination (HR) and gene reversion (GR) in yeast. We thought to exploit yeast genetics to shed light on BRCA1-induced genome instability and tumorigenesis. We determined the effect on GR of several neutral and pathogenic BRCA1 variants in the yeast strain RSY6wt and its isogenic DSB repair mutants, such as mre11∆, rad50∆ and rad51∆. In the RSY6wt, four out of five pathogenic and two out of six neutral variants significantly increased GR; rad51∆ strain, the pathogenic variants C61G and A1708E induced a weak but significant increase in GR. On the other hand, in rad50∆ mutant expressing the pathogenic variants localised at the BRCT domain, a further GR increase was seen. The neutral variant N132K and the VUS A1789T induced a weak GR increase in mre11∆ mutant. Thus, BRCA1 missense variants require specific genetic functions and presumably induced GR by different mechanisms. As DNA repair is regulated by cell cycle, we determined the effect on GR of BRCA1 variants in cell cycle-arrested RSYwt cells. GR is highly BRCA1-inducible in S-phase-arrested cells as compared to G1 or G2. Sequence analysis of genomic DNA from ILV1 revertant clones showed that BRCA1-induced ilv1-92 reversion by base substitution when GR is at least 6-fold over the control. Our study demonstrated that BRCA1 may interfere with yeast DNA repair functions that are active in S-phase causing high level of GR. In addition, we confirmed here that yeast could be a reliable model to investigate the mechanism and genetic requirements of BRCA1-induced genome instability. Finally, developing yeast-based assays to characterise BRCA1 missense variants could be useful to design more precise therapies.
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Affiliation(s)
- Samuele Lodovichi
- Yeast Genetics and Genomics, Laboratory of Functional Genetics and Genomics, Institute of Clinical Physiology, CNR, Pisa, Italy
| | - Francesca Bellè
- Yeast Genetics and Genomics, Laboratory of Functional Genetics and Genomics, Institute of Clinical Physiology, CNR, Pisa, Italy
| | - Tiziana Cervelli
- Yeast Genetics and Genomics, Laboratory of Functional Genetics and Genomics, Institute of Clinical Physiology, CNR, Pisa, Italy
| | - Alessandra Lorenzoni
- Yeast Genetics and Genomics, Laboratory of Functional Genetics and Genomics, Institute of Clinical Physiology, CNR, Pisa, Italy
| | - Luisa Maresca
- Yeast Genetics and Genomics, Laboratory of Functional Genetics and Genomics, Institute of Clinical Physiology, CNR, Pisa, Italy
- Molecular Genetics Unit, Department of Laboratory Medicine, University Hospital of Pisa, Pisa, Italy
| | - Cristina Cozzani
- Yeast Genetics and Genomics, Laboratory of Functional Genetics and Genomics, Institute of Clinical Physiology, CNR, Pisa, Italy
| | - Maria Adelaide Caligo
- Molecular Genetics Unit, Department of Laboratory Medicine, University Hospital of Pisa, Pisa, Italy
| | - Alvaro Galli
- Yeast Genetics and Genomics, Laboratory of Functional Genetics and Genomics, Institute of Clinical Physiology, CNR, Pisa, Italy
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8
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Lai KN, Ho WK, Kang IN, Kang PCE, Phuah SY, Mariapun S, Yip CH, Mohd Taib NA, Teo SH. Characterization of BRCA1 and BRCA2 variants in multi-ethnic Asian cohort from a Malaysian case-control study. BMC Cancer 2017; 17:149. [PMID: 28222693 PMCID: PMC5320733 DOI: 10.1186/s12885-017-3099-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/31/2017] [Indexed: 11/18/2022] Open
Abstract
Background Genetic testing for BRCA1 and BRCA2 has led to the accurate identification of individuals at higher risk of cancer and the development of new therapies. Approximately 10-20% of the genetic testing for BRCA1 and BRCA2 leads to the identification of variants of uncertain significance (VUS), with higher proportions in Asians. We investigated the functional significance of 7 BRCA1 and 25 BRCA2 variants in a multi-ethnic Asian cohort using a case-control approach. Methods The MassARRAY genotyping was conducted in 1,394 Chinese, 406 Malay and 310 Indian breast cancer cases and 1,071 Chinese, 167 Malay and 255 Indian healthy controls. The association of individual variant with breast cancer risk was analyzed using logistic regression model adjusted for ethnicity, age and family history. Results Our study confirmed BRCA2 p.Ile3412Val is presented in >2% of unaffected women and is likely benign, and BRCA2 p.Ala1996Thr which is predicted to be likely pathogenic by in-silico models is presented in 2% of healthy Indian women suggesting that it may not be associated with breast cancer risk. Single-variant analysis suggests that BRCA1 p.Arg762Ser may be associated with breast cancer risk (OR = 7.4; 95% CI, 0.9–62.3; p = 0.06). Conclusions Our study shows that BRCA2 p.Ile3412Val and p.Ala1996Thr are likely benign and highlights the need for population-specific studies to determine the likely functional significance of population-specific variants. Our study also suggests that BRCA1 p.Arg762Ser may be associated with increased risk of breast cancer but other methods or larger studies are required to determine a more precise estimate of breast cancer risk. Electronic supplementary material The online version of this article (doi:10.1186/s12885-017-3099-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kah Nyin Lai
- Cancer Research Malaysia, 1 Jalan SS12/1A, 47500, Subang Jaya, Selangor, Malaysia
| | - Weang Kee Ho
- Department of Applied Mathematics, Faculty of Engineering, The University of Nottingham Malaysia Campus, 43500, Semenyih, Selangor, Malaysia
| | - In Nee Kang
- Cancer Research Malaysia, 1 Jalan SS12/1A, 47500, Subang Jaya, Selangor, Malaysia
| | - Peter Choon Eng Kang
- Cancer Research Malaysia, 1 Jalan SS12/1A, 47500, Subang Jaya, Selangor, Malaysia
| | - Sze Yee Phuah
- Cancer Research Malaysia, 1 Jalan SS12/1A, 47500, Subang Jaya, Selangor, Malaysia
| | - Shivaani Mariapun
- Cancer Research Malaysia, 1 Jalan SS12/1A, 47500, Subang Jaya, Selangor, Malaysia
| | - Cheng-Har Yip
- Subang Jaya Medical Centre, 1 Jalan SS12/1A, 47500, Subang Jaya, Selangor, Malaysia
| | - Nur Aishah Mohd Taib
- Breast Cancer Research Unit, University Malaya Cancer Research Institute, Faculty of Medicine, University Malaya Medical Centre, University Malaya, 50603, Kuala Lumpur, Malaysia.,Department of Surgery, Faculty of Medicine, University Malaya Medical Centre, 50603, Kuala Lumpur, Malaysia
| | - Soo-Hwang Teo
- Cancer Research Malaysia, 1 Jalan SS12/1A, 47500, Subang Jaya, Selangor, Malaysia. .,Breast Cancer Research Unit, University Malaya Cancer Research Institute, Faculty of Medicine, University Malaya Medical Centre, University Malaya, 50603, Kuala Lumpur, Malaysia. .,Department of Surgery, Faculty of Medicine, University Malaya Medical Centre, 50603, Kuala Lumpur, Malaysia.
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9
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San Lucas FA, Allenson K, Bernard V, Castillo J, Kim DU, Ellis K, Ehli EA, Davies GE, Petersen JL, Li D, Wolff R, Katz M, Varadhachary G, Wistuba I, Maitra A, Alvarez H. Minimally invasive genomic and transcriptomic profiling of visceral cancers by next-generation sequencing of circulating exosomes. Ann Oncol 2015; 27:635-41. [PMID: 26681674 PMCID: PMC4803451 DOI: 10.1093/annonc/mdv604] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 12/07/2015] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND The ability to perform comprehensive profiling of cancers at high resolution is essential for precision medicine. Liquid biopsies using shed exosomes provide high-quality nucleic acids to obtain molecular characterization, which may be especially useful for visceral cancers that are not amenable to routine biopsies. PATIENTS AND METHODS We isolated shed exosomes in biofluids from three patients with pancreaticobiliary cancers (two pancreatic, one ampullary). We performed comprehensive profiling of exoDNA and exoRNA by whole genome, exome and transcriptome sequencing using the Illumina HiSeq 2500 sequencer. We assessed the feasibility of calling copy number events, detecting mutational signatures and identifying potentially actionable mutations in exoDNA sequencing data, as well as expressed point mutations and gene fusions in exoRNA sequencing data. RESULTS Whole-exome sequencing resulted in 95%-99% of the target regions covered at a mean depth of 133-490×. Genome-wide copy number profiles, and high estimates of tumor fractions (ranging from 56% to 82%), suggest robust representation of the tumor DNA within the shed exosomal compartment. Multiple actionable mutations, including alterations in NOTCH1 and BRCA2, were found in patient exoDNA samples. Further, RNA sequencing of shed exosomes identified the presence of expressed fusion genes, representing an avenue for elucidation of tumor neoantigens. CONCLUSIONS We have demonstrated high-resolution profiling of the genomic and transcriptomic landscapes of visceral cancers. A wide range of cancer-derived biomarkers could be detected within the nucleic acid cargo of shed exosomes, including copy number profiles, point mutations, insertions, deletions, gene fusions and mutational signatures. Liquid biopsies using shed exosomes has the potential to be used as a clinical tool for cancer diagnosis, therapeutic stratification and treatment monitoring, precluding the need for direct tumor sampling.
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Affiliation(s)
- F A San Lucas
- Department of Translational Molecular Pathology Department of Pathology
| | - K Allenson
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston
| | - V Bernard
- Department of Pathology The University of Texas Graduate School of Biomedical Sciences at Houston, Houston
| | | | | | | | - E A Ehli
- Avera Institute for Human Genetics, Sioux Falls
| | - G E Davies
- Avera Institute for Human Genetics, Sioux Falls
| | | | - D Li
- Department of Gastrointestinal (GI) Medical Oncology
| | - R Wolff
- Department of Gastrointestinal (GI) Medical Oncology
| | - M Katz
- Department of Gastrointestinal (GI) Medical Oncology
| | | | - I Wistuba
- Department of Translational Molecular Pathology
| | - A Maitra
- Department of Translational Molecular Pathology Department of Pathology Sheikh Ahmed Pancreatic Cancer Research Center, The University of Texas MD Anderson Cancer Center, Houston, USA
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10
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Zick A, Cohen S, Hamburger T, Goldberg Y, Zvi N, Sagi M, Peretz T. A BRCA1 Frame Shift Mutation in Women of Kurdish Jewish Descent. ACTA ACUST UNITED AC 2015. [DOI: 10.2174/1874220301401010031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hereditary cancer comprises more than 10% of all breast cancer cases. In patients with a family history suggestive of a hereditary component, a mutation is often identified in the high penetrant genes BRCA1 and BRCA2. Several founder mutations have been detected in some Jewish communities, yet no BRCA1/2 founder mutation had been known in Kurdish Jews. Here, we describe the validation of a 22 hereditary cancer gene panel and a BRCA1 mutation found in 4 women from 2 unrelated Kurdish Jewish families utilizing this gene panel.
A panel spanning the coding sequences of 22 familial cancer-related genes was planned. Genomic DNA was taken to create libraries using this panel, which were then sequenced using the Ion Torrent PGM. The panel's validity in detecting mutations was tested on 25 samples with previously identified point mutations in the BRCA1, BRCA2, MLH1 and PMS2 genes; the panel did not test for large deletions or insertions. All previously identified mutations were detected. Next, a different set of 40 cancer patients of Kurdish Jewish descent diagnosed with cancer before the age of 50 years was tested. We identified the BRCA1 mutation, c.224_227delAAAG (dbSNP ID rs80357697), in 4 women from 2 unrelated Jewish Kurdish families. The probands were diagnosed with cancer at a young age and had significant family history, suggesting a founder mutation in this population. We suggest testing Kurdish Jewish women with a personal or family history of breast and/ or ovarian cancer for this mutation.
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11
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Guidugli L, Carreira A, Caputo SM, Ehlen A, Galli A, Monteiro ANA, Neuhausen SL, Hansen TVO, Couch FJ, Vreeswijk MPG. Functional assays for analysis of variants of uncertain significance in BRCA2. Hum Mutat 2013; 35:151-64. [PMID: 24323938 DOI: 10.1002/humu.22478] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 10/28/2013] [Indexed: 01/11/2023]
Abstract
Missense variants in the BRCA2 gene are routinely detected during clinical screening for pathogenic mutations in patients with a family history of breast and ovarian cancer. These subtle changes frequently remain of unknown clinical significance because of the lack of genetic information that may help establish a direct correlation with cancer predisposition. Therefore, alternative ways of predicting the pathogenicity of these variants are urgently needed. Since BRCA2 is a protein involved in important cellular mechanisms such as DNA repair, replication, and cell cycle control, functional assays have been developed that exploit these cellular activities to explore the impact of the variants on protein function. In this review, we summarize assays developed and currently utilized for studying missense variants in BRCA2. We specifically depict details of each assay, including variants of uncertain significance analyzed, and describe a validation set of (genetically) proven pathogenic and neutral missense variants to serve as a golden standard for the validation of each assay. Guidelines are proposed to enable implementation of laboratory-based methods to assess the impact of the variant on cancer risk.
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Affiliation(s)
- Lucia Guidugli
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
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Spugnesi L, Balia C, Collavoli A, Falaschi E, Quercioli V, Caligo MA, Galli A. Effect of the expression of BRCA2 on spontaneous homologous recombination and DNA damage-induced nuclear foci in Saccharomyces cerevisiae. Mutagenesis 2013; 28:187-95. [DOI: 10.1093/mutage/ges069] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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