scholarly journals Novel candidates of pathogenic variants of the BRCA1 and BRCA2 genes from a dataset of 3,552 Japanese whole genomes (3.5KJPNv2)

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0236907
Author(s):  
Hideki Tokunaga ◽  
Keita Iida ◽  
Atsushi Hozawa ◽  
Soichi Ogishima ◽  
Yoh Watanabe ◽  
...  
Keyword(s):  
Prospective Cohort ◽  
Cancer Syndrome ◽  
Brca1 And Brca2 ◽  
Cancer History ◽  
Genome Data ◽  
Pathogenic Variants ◽  
Uncertain Significance ◽  
Prospective Cohorts ◽  
Personalized Health ◽  
Personalized Health Care

Identification of the population frequencies of definitely pathogenic germline variants in two major hereditary breast and ovarian cancer syndrome (HBOC) genes, BRCA1/2, is essential to estimate the number of HBOC patients. In addition, the identification of moderately penetrant HBOC gene variants that contribute to increasing the risk of breast and ovarian cancers in a population is critical to establish personalized health care. A prospective cohort subjected to genome analysis can provide both sets of information. Computational scoring and prospective cohort studies may help to identify such likely pathogenic variants in the general population. We annotated the variants in the BRCA1 and BRCA2 genes from a dataset of 3,552 whole-genome sequences obtained from members of a prospective cohorts with genome data in the Tohoku Medical Megabank Project (TMM) with InterVar software. Computational impact scores (CADD_phred and Eigen_raw) and minor allele frequencies (MAFs) of pathogenic (P) and likely pathogenic (LP) variants in ClinVar were used for filtration criteria. Familial predispositions to cancers among the 35,000 TMM genome cohort participants were analyzed to verify the identified pathogenicity. Seven potentially pathogenic variants were newly identified. The sisters of carriers of these moderately deleterious variants and definite P and LP variants among members of the TMM prospective cohort showed a statistically significant preponderance for cancer onset, from the self-reported cancer history. Filtering by computational scoring and MAF is useful to identify potentially pathogenic variants in BRCA genes in the Japanese population. These results should help to follow up the carriers of variants of uncertain significance in the HBOC genes in the longitudinal prospective cohort study.

scholarly journals Novel candidates of pathogenic variants of the BRCA1 and BRCA2 genes in a 3,552 Japanese whole-genome sequence dataset (3.5KJPNv2)

2020 ◽  
Author(s):  
Hideki Tokunaga ◽  
Keita Iida ◽  
Atsushi Hozawa ◽  
Soichi Ogishima ◽  
Yoh Watanabe ◽  
...  
Keyword(s):  
Prospective Cohort ◽  
Clinical Evidence ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Cancer Syndrome ◽  
Brca1 And Brca2 ◽  
Cancer History ◽  
Pathogenic Variants ◽  
Uncertain Significance

AbstractIdentification of pathogenic germline variants yet no clinical evidence in BRCA genes has become important in patient care of hereditary breast and ovarian cancer syndrome (HBOC). Computational scoring and prospective cohort studies may help to identify such pathogenic variants. We annotated the variants in the BRCA1 and BRCA2 genes from a dataset of 3,552 whole-genome sequences obtained from members of the genome cohorts by Tohoku Medical Megabank Project (TMM) with the InterVar software. Computational impact scores (CADD_phred and Eigen_raw) and minor allele frequencies (MAF) of pathogenic (P) and likely pathogenic (LP) variants in ClinVar are used for filtration criteria. Familial predispositions in cancers among the 35,000 TMM genome cohort participants are analyzed to verify the pathogenicity. Seven potentially pathogenic variants were newly identified. Carriers of these potential pathogenic variants and definite P and LP variants among participants of the TMM prospective cohort show a statistically significant preponderance in cancer onset in sisters in the self-reported cancer history. Filtering by computational scoring and MAF is useful to identify potential pathogenic variants in BRCA genes for Japanese population. These results will be helpful to follow up the carriers of variants of uncertain significance in the HBOC genes.

scholarly journals Beyond BRCA1 and BRCA2: Deleterious Variants in DNA Repair Pathway Genes in Italian Families with Breast/Ovarian and Pancreatic Cancers

2020 ◽  
Vol 9 (9) ◽  
pp. 3003
Author(s):  
Aldo Germani ◽  
Simona Petrucci ◽  
Laura De Marchis ◽  
Fabio Libi ◽  
Camilla Savio ◽  
...  
Keyword(s):  
Therapeutic Approaches ◽  
Brca1 And Brca2 ◽  
Pathogenic Variants ◽  
Pancreatic Cancers ◽  
Damage Repair ◽  
High Incidence ◽  
Uncertain Significance ◽  
Generation Sequencing ◽  
Index Cases ◽  
Multigene Panel

The 5–10% of breast/ovarian cancers (BC and OC) are inherited, and germline pathogenic (P) variants in DNA damage repair (DDR) genes BRCA1 and BRCA2 explain only 10–20% of these cases. Currently, new DDR genes have been related to BC/OC and to pancreatic (PC) cancers, but the prevalence of P variants remains to be explored. The purpose of this study was to investigate the spectrum and the prevalence of pathogenic variants in DDR pathway genes other than BRCA1/2 and to correlate the genotype with the clinical phenotype. A cohort of 113 non-BRCA patients was analyzed by next-generation sequencing using a multigene panel of the 25 DDR pathways genes related to BC, OC, and PC. We found 43 unique variants in 18 of 25 analyzed genes, 14 classified as P/likely pathogenic (LP) and 28 as variants of uncertain significance (VUS). Deleterious variants were identified in 14% of index cases, whereas a VUS was identified in 20% of the probands. We observed a high incidence of deleterious variants in the CHEK2 gene, and a new pathogenic variant was detected in the RECQL gene. These results supported the clinical utility of multigene panel to increase the detection of P/LP carriers and to identify new actionable pathogenic gene variants useful for preventive and therapeutic approaches.

Reclassification of BRCA1 and BRCA2 variants of uncertain significance: a multifactorial analysis of multicentre prospective cohort

2018 ◽  
Vol 55 (12) ◽  
pp. 794-802 ◽  
Author(s):  
Jee-Soo Lee ◽  
Sohee Oh ◽  
Sue Kyung Park ◽  
Min-Hyuk Lee ◽  
Jong Won Lee ◽  
...  
Keyword(s):  
Breast Cancer ◽  
External Validation ◽  
Brca1 And Brca2 ◽  
Clinical Genetic ◽  
Validation Data ◽  
Data Set ◽  
Variants Of Uncertain Significance ◽  
Pathogenic Variants ◽  
Uncertain Significance ◽  
Highly Correlated

BackgroundBRCA1 and BRCA2 (BRCA1/2) variants classified ambiguously as variants of uncertain significance (VUS) are a major challenge for clinical genetic testing in breast cancer; their relevance to the cancer risk is unclear and the association with the response to specific BRCA1/2-targeted agents is uncertain. To minimise the proportion of VUS in BRCA1/2, we performed the multifactorial likelihood analysis and validated this method using an independent cohort of patients with breast cancer.MethodsWe used a data set of 2115 patients with breast cancer from the nationwide multicentre prospective Korean Hereditary Breast Cancer study. In total, 83 BRCA1/2 VUSs (BRCA1, n=26; BRCA2, n=57) were analysed. The multifactorial probability was estimated by combining the prior probability with the overall likelihood ratio derived from co-occurrence of each VUS with pathogenic variants, personal and family history, and tumour characteristics. The classification was compared with the interpretation according to the American College of Medical Genetics and Genomics–Association for Molecular Pathology (ACMG/AMP) guidelines. An external validation was conducted using independent data set of 810 patients.ResultsWe were able to redefine 38 VUSs (BRCA1, n=10; BRCA2, n=28). The revised classification was highly correlated with the ACMG/AMP guideline-based interpretation (BRCA1, p for trend=0.015; BRCA2, p=0.001). Our approach reduced the proportion of VUS from 19% (154/810) to 8.9% (72/810) in the retrospective validation data set.ConclusionThe classification in this study would minimise the ‘uncertainty’ in clinical interpretation, and this validated multifactorial model can be used for the reliable annotation of BRCA1/2 VUSs.

scholarly journals Non-BRCA1/2 Variants Detected in a High-Risk Chilean Cohort With a History of Breast and/or Ovarian Cancer

2019 ◽  
pp. 1-14 ◽  
Author(s):  
Christina Adaniel ◽  
Francisca Salinas ◽  
Juan Manuel Donaire ◽  
Maria Eugenia Bravo ◽  
Octavio Peralta ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Genetic Testing ◽  
High Risk ◽  
Genetic Predisposition ◽  
Cancer Syndrome ◽  
Breast And Ovarian Cancer ◽  
Brca1 And Brca2 ◽  
Pathogenic Variants ◽  
Cancer Program ◽  
Genetic Test Results

PURPOSE Little is known about the genetic predisposition to breast and ovarian cancer among the Chilean population, in particular genetic predisposition beyond BRCA1 and BRCA2 mutations. In the current study, we aim to describe the germline variants detected in individuals who were referred to a hereditary cancer program in Santiago, Chile. METHODS Data were retrospectively collected from the registry of the High-Risk Breast and Ovarian Cancer Program at Clínica Las Condes, Santiago, Chile. Data captured included index case diagnosis, ancestry, family history, and genetic test results. RESULTS Three hundred fifteen individuals underwent genetic testing during the study period. The frequency of germline pathogenic and likely pathogenic variants in a breast or ovarian cancer predisposition gene was 20.3%. Of those patients who underwent testing with a panel of both high- and moderate-penetrance genes, 10.5% were found to have pathogenic or likely pathogenic variants in non- BRCA1/2 genes. CONCLUSION Testing for non- BRCA1 and -2 mutations may be clinically relevant for individuals who are suspected to have a hereditary breast or ovarian cancer syndrome in Chile. Comprehensive genetic testing of individuals who are at high risk is necessary to further characterize the genetic susceptibility to cancer in Chile.

scholarly journals Interpretation of BRCA2 Splicing Variants: A Case Series of Challenging Variant Interpretations and the Importance of Functional RNA Analysis

2021 ◽  
Author(s):  
Paola Nix ◽  
Erin Mundt ◽  
Bradford Coffee ◽  
Elizabeth Goossen ◽  
Bryan M. Warf ◽  
...  
Keyword(s):  
Rna Splicing ◽  
Case Series ◽  
Cancer History ◽  
Rna Analysis ◽  
Pathogenic Variants ◽  
Conflicting Evidence ◽  
Increased Risk ◽  
Splicing Variants ◽  
Uncertain Significance ◽  
In Silico Models

AbstractA substantial proportion of pathogenic variants associated with an increased risk of hereditary cancer are sequence variants affecting RNA splicing. The classification of these variants can be complex when both non-functional and functional transcripts are produced from the variant allele. We present four BRCA2 splice site variants with complex variant interpretations (BRCA2 c.68-3T>G, c.68-2A>G, c.425G>T, c.8331+2T>C). Evidence supporting a pathogenic classification is available for each variant, including in silico models, absence in population databases, and published functional data. However, comprehensive RNA analysis showed that some functional transcript may be produced by each variant. BRCA2 c.68-3T>G results in a partial splice defect. For BRCA2 c.68-2A>G and c.425G>T, aberrant splicing was shown to produce a potentially functional, in-frame transcript. BRCA2 c.8331+2T>C may utilize a functional GC donor in place of the wild-type GT donor. The severity of cancer history for carriers of these variants was also assessed using a history weighting algorithm and was not consistent with pathogenic controls (carriers of known pathogenic variants in BRCA2). Due to the conflicting evidence, our laboratory classifies these BRCA2 variants as variants of uncertain significance. This highlights the importance of evaluating new and existing evidence to ensure accurate variant classification and appropriate patient care.

scholarly journals The Genetic Analyses of French Canadians of Quebec Facilitate the Characterization of New Cancer Predisposing Genes Implicated in Hereditary Breast and/or Ovarian Cancer Syndrome Families

Cancers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 3406
Author(s):  
Caitlin T. Fierheller ◽  
Wejdan M. Alenezi ◽  
Patricia N. Tonin
Keyword(s):  
Ovarian Cancer ◽  
Genetic Architecture ◽  
French Canadian ◽  
Cancer Syndrome ◽  
French Canadians ◽  
Brca1 And Brca2 ◽  
Genetic Analyses ◽  
Pathogenic Variants ◽  
Predisposing Genes

The French Canadian population of the province of Quebec has been recognized for its contribution to research in medical genetics, especially in defining the role of heritable pathogenic variants in cancer predisposing genes. Multiple carriers of a limited number of pathogenic variants in BRCA1 and BRCA2, the major risk genes for hereditary breast and/or ovarian cancer syndrome families, have been identified in French Canadians, which is in stark contrast to the array of over 2000 different pathogenic variants reported in each of these genes in other populations. As not all such cancer syndrome families are explained by BRCA1 and BRCA2, newly proposed gene candidates identified in other populations have been investigated for their role in conferring risk in French Canadian cancer families. For example, multiple carriers of distinct variants were identified in PALB2 and RAD51D. The unique genetic architecture of French Canadians has been attributed to shared ancestry due to common ancestors of early settlers of this population with origins mainly from France. In this review, we discuss the merits of genetically characterizing cancer predisposing genes in French Canadians of Quebec. We focused on genes that have been implicated in hereditary breast and/or ovarian cancer syndrome families as they have been the most thoroughly characterized cancer syndromes in this population. We describe how genetic analyses of French Canadians have facilitated: (i) the classification of variants in BRCA1 and BRCA2; (ii) the identification and classification of variants in newly proposed breast and/or ovarian cancer predisposing genes; and (iii) the identification of a new breast cancer predisposing gene candidate, RECQL. The genetic architecture of French Canadians provides a unique opportunity to evaluate new candidate cancer predisposing genes regardless of the population in which they were identified.

scholarly journals Prevalence and Spectrum of Germline BRCA1 and BRCA2 Variants of Uncertain Significance in Breast/Ovarian Cancer: Mysterious Signals From the Genome

2021 ◽  
Vol 11 ◽  
Author(s):  
Daniele Fanale ◽  
Alessia Fiorino ◽  
Lorena Incorvaia ◽  
Alessandra Dimino ◽  
Clarissa Filorizzo ◽  
...  
Keyword(s):  
High Risk ◽  
Clinical Significance ◽  
Clinical Management ◽  
University Hospital ◽  
Sequencing Analysis ◽  
Brca1 And Brca2 ◽  
Variants Of Uncertain Significance ◽  
Pathogenic Variants ◽  
Risk Variants ◽  
Uncertain Significance

About 10–20% of breast/ovarian (BC/OC) cancer patients undergoing germline BRCA1/2 genetic testing have been shown to harbor Variants of Uncertain Significance (VUSs). Since little is known about the prevalence of germline BRCA1/2 VUS in Southern Italy, our study aimed at describing the spectrum of these variants detected in BC/OC patients in order to improve the identification of potentially high-risk BRCA variants helpful in patient clinical management. Eight hundred and seventy-four BC or OC patients, enrolled from October 2016 to December 2020 at the “Sicilian Regional Center for the Prevention, Diagnosis and Treatment of Rare and Heredo-Familial Tumors” of University Hospital Policlinico “P. Giaccone” of Palermo, were genetically tested for germline BRCA1/2 variants through Next-Generation Sequencing analysis. The mutational screening showed that 639 (73.1%) out of 874 patients were BRCA-w.t., whereas 67 (7.7%) were carriers of germline BRCA1/2 VUSs, and 168 (19.2%) harbored germline BRCA1/2 pathogenic/likely pathogenic variants. Our analysis revealed the presence of 59 different VUSs detected in 67 patients, 46 of which were affected by BC and 21 by OC. Twenty-one (35.6%) out of 59 variants were located on BRCA1 gene, whereas 38 (64.4%) on BRCA2. We detected six alterations in BRCA1 and two in BRCA2 with unclear interpretation of clinical significance. Familial anamnesis of a patient harboring the BRCA1-c.3367G>T suggests for this variant a potential of pathogenicity, therefore it should be carefully investigated. Understanding clinical significance of germline BRCA1/2 VUS could improve, in future, the identification of potentially high-risk variants useful for clinical management of BC or OC patients and family members.

scholarly journals GFP-Fragment Reassembly Screens for the Functional Characterization of Variants of Uncertain Significance in Protein Interaction Domains of the BRCA1 and BRCA2 Genes

Cancers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 151 ◽  
Author(s):  
Laura Caleca ◽  
Mara Colombo ◽  
Thomas van Overeem Hansen ◽  
Conxi Lázaro ◽  
Siranoush Manoukian ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Functional Characterization ◽  
Brca1 And Brca2 ◽  
Vitro Assay ◽  
Variants Of Uncertain Significance ◽  
Pathogenic Variants ◽  
Brca1 And Brca2 Genes ◽  
Uncertain Significance ◽  
Genome Protection

Genetic testing for BRCA1 and BRCA2 genes has led to the identification of many unique variants of uncertain significance (VUS). Multifactorial likelihood models that predict the odds ratio for VUS in favor or against cancer causality, have been developed, but their use is conditioned by the amount of necessary data, which are difficult to obtain if a variant is rare. As an alternative, variants mapping to the coding regions can be examined using in vitro functional assays. BRCA1 and BRCA2 proteins promote genome protection by interacting with different proteins. In this study, we assessed the functional effect of two sets of variants in BRCA genes by exploiting the green fluorescent protein (GFP)-reassembly in vitro assay, which was set-up to test the BRCA1/BARD1, BRCA1/UbcH5a, and BRCA2/DSS1 interactions. Based on the findings observed for the validation panels of previously classified variants, BRCA1/UbcH5a and BRCA2/DSS1 binding assays showed 100% sensitivity and specificity in identifying pathogenic and non-pathogenic variants. While the actual efficiency of these assays in assessing the clinical significance of BRCA VUS has to be verified using larger validation panels, our results suggest that the GFP-reassembly assay is a robust method to identify variants affecting normal protein functioning and contributes to the classification of VUS.

scholarly journals Spectrum of Germline BRCA1 and BRCA2 Variants Identified in 2351 Ovarian and Breast Cancer Patients Referring to a Reference Cancer Hospital of Rome

Cancers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1286 ◽  
Author(s):  
Concetta Santonocito ◽  
Roberta Rizza ◽  
Ida Paris ◽  
Laura De Marchis ◽  
Carmela Paolillo ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Breast Cancer Patients ◽  
Brca1 And Brca2 ◽  
Pathogenic Variants ◽  
Uncertain Significance ◽  
In Vitro Diagnostic ◽  
Variant Frequency ◽  
Next Generation Sequencing Ngs ◽  
Generation Sequencing

Pathogenic variants (PVs) carriers in BRCA1 or BRCA2 are associated with an elevated lifetime risk of developing breast cancer (BC) and/or ovarian cancer (OC). The prevalence of BRCA1 and BRCA2 germline alterations is extremely variable among different ethnic groups. Particularly, the rate of variants in Italian BC and/or OC families is rather controversial and ranges from 8% to 37%, according to different reports. By In Vitro Diagnostic (IVD) next generation sequencing (NGS)-based pipelines, we routinely screened thousands of patients with either sporadic or cancer family history. By NGS, we identified new PVs and some variants of uncertain significance (VUS) which were also evaluated in silico using dedicated tools. We report in detail data regarding BRCA1/2 variants identified in 517 out of 2351 BC and OC patients. The aim of this study was to report the incidence and spectrum of BRCA1/2 variants observed in BC and/or OC patients, tested in at Policlinico Gemelli Foundation Hospital, the origin of which is mainly from Central and Southern Italy. This study provides an overview of the variant frequency in these geographic areas of Italy and provides data that could be used in the clinical management of patients.

scholarly journals Genome-Wide Gene Expression Analyses of BRCA1- and BRCA2-Associated Breast and Ovarian Tumours

Cancers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 3015 ◽  
Author(s):  
George A. R. Wiggins ◽  
Logan C. Walker ◽  
John F. Pearson
Keyword(s):  
Gene Expression ◽  
Genetic Testing ◽  
Expression Profiles ◽  
Pathogenic Variant ◽  
Individual Risk ◽  
Cancer Genetic ◽  
Brca1 And Brca2 ◽  
Pathogenic Variants ◽  
Uncertain Significance ◽  
The Impact

Germline pathogenic variants in BRCA1 and BRCA2 increase cumulative lifetime risk up to 75% for breast cancer and 76% for ovarian cancer. Genetic testing for BRCA1 and BRCA2 pathogenic variants has become an important part of clinical practice for cancer risk assessment and for reducing individual risk of developing cancer. Genetic testing can produce three outcomes: positive (a pathogenic variant), uninformative (no pathogenic variant) and uncertain significance (a variant of unknown clinical significance). More than one third of BRCA1 and BRCA2 variants identified have been classified as variants of uncertain significance, presenting a challenge for clinicians. To address this important clinical challenge, a number of studies have been undertaken to establish a gene expression phenotype for pathogenic BRCA1 and BRCA2 variant carriers in several diseased and normal tissues. However, the consistency of gene expression phenotypes described in studies has been poor. To determine if gene expression analysis has been a successful approach for variant classification, we describe the design and comparability of 23 published gene expression studies that have profiled cells from BRCA1 and BRCA2 pathogenic variant carriers. We show the impact of advancements in expression-based technologies, the importance of developing larger study cohorts and the necessity to better understand variables affecting gene expression profiles across different tissue types.

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