Nonoptical massive parallel DNA sequencing of BRCA1 and BRCA2 genes in a diagnostic setting

The introduction of the benchtop massive parallel sequencers made it possible for the majority of clinical diagnostic laboratories to gain access to this fast evolving technology. In this study, using the Ion Torrent Personal Genome Machine, we present a strategy for the molecular diagnosis of hereditary breast and ovarian cancer and respective analytical validation. The methodology relies on a multiplex PCR amplification of the BRCA1 and BRCA2 genes combined with a variant prioritization pipeline, designed to minimize the number of false-positive calls without the introduction of false-negative results. A training set of samples was used to optimize the entire process, and a second set was used to validate and independently evaluate the performance of the workflow. Performing the study in a blind manner relative to the variants in the samples and using conventional Sanger sequencing as standard, the workflow resulted in a strategy with a maximum analytical sensitivity ≥98.6% with a confidence of 95% and a specificity of 96.9%. Importantly, no true variant was missed. This study presents a comprehensive massive parallel sequencing-Sanger sequencing based strategy, which results in a high analytical sensitivity assay that provides a time- and cost-effective strategy for the identification of mutations in the BRCA1 and BRCA2 genes.