Next-Generation Sequencing of the BRCA1 and BRCA2 Genes for the Diagnostics of Breast and/or Ovarian Cancer

J Mol Diagn 2015, 17: 162e170

Genetic testing for hereditary breast and/or ovarian cancer mostly relies on laborious molecular tools that use Sanger sequencing to scan for mutations in the BRCA1 and BRCA2 genes. We explored a more efficient genetic screening strategy based on next-generation sequencing of the BRCA1 and BRCA2 genes in 210 hereditary breast and/or ovarian cancer patients. We first validated this approach in a cohort of 115 samples with previously known BRCA1 and BRCA2 mutations and polymorphisms. Genomic DNA was amplified using the Ion AmpliSeq BRCA1 and BRCA2 panel. The DNA Libraries were pooled, barcoded, and sequenced using an Ion Torrent Personal Genome Machine sequencer. The combination of different robust bioinformatics tools allowed detection of all previously known pathogenic mutations and polymorphisms in the 115 samples, without detecting spurious pathogenic calls. We then used the same assay in a discovery cohort of 95 uncharacterized hereditary breast and/or ovarian cancer patients for BRCA1 and BRCA2. In addition, we describe the allelic frequencies across 210 hereditary breast and/or ovarian cancer patients of 74 unique definitely and likely pathogenic and uncertain BRCA1 and BRCA2 variants, some of which have not been previously annotated in the public databases. Targeted next-generation sequencing is ready to substitute classic molecular methods to perform genetic testing on the BRCA1 and BRCA2 genes and provides a greater opportunity for more comprehensive testing of at-risk patients.

For a deeper insight, please watch Dr Daniel Trujillano, Senior Director of Bioinformatics at CENTOGENE, explaining the background and details.