BRCA1 and BRCA2 Testing through Next Generation Sequencing in a Small Cohort of Italian Breast/Ovarian Cancer Patients: Novel Pathogenic and Unknown Clinical Significance Variants

Int J Mol Sci. 2019 Jul 12;20(14):3442. doi: 10.3390/ijms20143442.

Abstract

The aim of this report is to describe results of BRCA1 and BRCA2 Next Generation Sequencing Analysis (NGS) analysis in 132 selected Italian patients with breast/ovarian cancer. A NGS pipeline with a reliable Copy Number Variation (CNV) prediction algorithm was applied. In addition, VarSome and Priors V2.0 Software were employed for in silico analysis of novel missense variants. A total of 37 BRCA1 and BRCA2 pathogenic variants were found in 34 unrelated subjects with a frequency of positive patients of 25.7% (34/132). Twenty-four deleterious variants were detected in BRCA1 (representing the 64.9% of all identified pathogenic defects) and thirteen (35.1% of all identified pathogenic variants) in BRCA2 gene. The percentage of patients carrying a variant of unknown significance (VUS) was 7.5% (10/132). In addition, seven novel variants (five in BRCA2 and two in BRCA1 gene), never previously reported, were identified. Our approach represents a robust and easy-to-use method for full BRCA1/2 screening. However, a consistent number of our high-risk families still remained without a satisfying answer. Necessarily, further collective efforts must be directed to a definitive classification of VUSs. The future auspice is that the use of multi-gene panel and more advanced screenings, such as whole exome sequencing and/or RNA seq, in routine diagnostics increases the detection rate.

Keywords: BRCA1/2 genes; NGS; breast cancer; genetic testing; molecular diagnosis; ovarian cancer.

MeSH terms

  • Adult
  • Aged
  • Alleles
  • Amino Acid Substitution
  • Biomarkers, Tumor
  • Breast Neoplasms / diagnosis
  • Breast Neoplasms / genetics*
  • Cohort Studies
  • Computational Biology / methods
  • DNA Copy Number Variations
  • DNA Mutational Analysis
  • Female
  • Genes, BRCA1*
  • Genes, BRCA2*
  • Genetic Association Studies* / methods
  • Genetic Predisposition to Disease*
  • Genetic Testing
  • Genotype
  • Germ-Line Mutation
  • High-Throughput Nucleotide Sequencing*
  • Humans
  • Italy
  • Middle Aged
  • Ovarian Neoplasms / diagnosis
  • Ovarian Neoplasms / genetics*
  • Pedigree

Substances

  • Biomarkers, Tumor