title: Implementation of next-generation sequencing for molecular diagnosis of hereditary breast and ovarian cancer highlights its genetic heterogeneity.
abstract: Molecular diagnosis of hereditary breast and ovarian cancer (HBOC) by standard methodologies has been limited to the BRCA1 and BRCA2 genes. With the recent development of new sequencing methodologies, the speed and efficiency of DNA testing have dramatically improved. The aim of this work was to validate the use of next-generation sequencing (NGS) for the detection of BRCA1/BRCA2 point mutations in a diagnostic setting and to study the role of other genes associated with HBOC in Portuguese families. A cohort of 94 high-risk families was included in the study, and they were initially screened for the two common founder mutations with variant-specific methods. Fourteen index patients were shown to carry the Portuguese founder mutation BRCA2 c.156_157insAlu, and the remaining 80 were analyzed in parallel by Sanger sequencing for the BRCA1/BRCA2 genes and by NGS for a panel of 17 genes that have been described as involved in predisposition to breast and/or ovarian cancer. A total of 506 variants in the BRCA1/BRCA2 genes were detected by both methodologies, with a 100 % concordance between them. This strategy allowed the detection of a total of 39 deleterious mutations in the 94 index patients, namely 10 in BRCA1 (25.6 %), 21 in BRCA2 (53.8 %), four in PALB2 (10.3 %), two in ATM (5.1 %), one in CHEK2 (2.6 %), and one in TP53 (2.6 %), with 20.5 % of the deleterious mutations being found in genes other than BRCA1/BRCA2. These results demonstrate the efficiency of NGS for the detection of BRCA1/BRCA2 point mutations and highlight the genetic heterogeneity of HBOC.
authors.affiliation: Cancer Genetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Rua Dr. António Bernardino de Almeida, 4200-072, Porto, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Pinto
authors.affiliation: Cancer Genetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Rua Dr. António Bernardino de Almeida, 4200-072, Porto, Portugal.
authors.forename: Paula
authors.initials: P
authors.lastname: Paulo
authors.affiliation: Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Santos
authors.affiliation: Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.
authors.forename: Patrícia
authors.initials: P
authors.lastname: Rocha
authors.affiliation: Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.
authors.forename: Carla
authors.initials: C
authors.lastname: Pinto
authors.affiliation: Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Veiga
authors.affiliation: Cancer Genetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Rua Dr. António Bernardino de Almeida, 4200-072, Porto, Portugal.
authors.forename: Manuela
authors.initials: M
authors.lastname: Pinheiro
authors.affiliation: Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Peixoto
authors.affiliation: Cancer Genetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Rua Dr. António Bernardino de Almeida, 4200-072, Porto, Portugal. manuel.teixeira@ipoporto.min-saude.pt.|Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal. manuel.teixeira@ipoporto.min-saude.pt.|Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal. manuel.teixeira@ipoporto.min-saude.pt.
authors.forename: Manuel R
authors.initials: MR
authors.lastname: Teixeira
mesh_terms: D000328:Adult; D064007:Ataxia Telangiectasia Mutated Proteins / Q000235:genetics; D019313:BRCA1 Protein / Q000235:genetics*; D024682:BRCA2 Protein / Q000235:genetics*; D064447:Checkpoint Kinase 2 / Q000235:genetics; D000076164:Fanconi Anemia Complementation Group N Protein / Q000235:genetics; D005260:Female; D018740:Genetic Heterogeneity; D020022:Genetic Predisposition to Disease; D061325:Hereditary Breast and Ovarian Cancer Syndrome / Q000175:diagnosis* / Q000235:genetics; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods*; D006801:Humans; D008875:Middle Aged; D017354:Point Mutation; D011174:Portugal; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA / Q000379:methods*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
chemical_list: D019313:BRCA1 Protein; C492913:BRCA1 protein, human; D024682:BRCA2 Protein; C551750:BRCA2 protein, human; D000076164:Fanconi Anemia Complementation Group N Protein; C512790:PALB2 protein, human; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D064447:Checkpoint Kinase 2; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C578634:CHEK2 protein, human
keywords: BRCA1; BRCA2; HBOC; Next-generation sequencing; Targeted sequencing