Multigene germline testing usefulness instead of BRCA1/2 single screening in triple negative breast cancer cases

Triple negative breast cancer is considered as the worst aggressive subtype with poor prognosis. Recent studies suggest a hereditary component is involved in TNBC development, especially in young patients. However, genetic spectrum remains unclear. Our purpose was to evaluate the usefulness of multigene panel testing in triple negative patients compared to overall breast cancer cases as well as contributing to elucidate which genes are most implicated in triple negative subtype development. Two breast cancer cohorts, comprising 100 triple negative breast cancer patients and 100 patients with other breast cancer subtypes, were analyzed by Next-Generation Sequencing using an On-Demand panel which included 35 predisposition cancer genes associated with inherited cancer susceptibility. The percentage of germline pathogenic variant carriers was higher in the triple negative cohort. ATM, PALB2, BRIP1 and TP53 were the most non-BRCA mutated genes. Moreover, triple negative breast cancer patients without family history related who were identified as carriers were diagnosed at significantly earlier age. As conclusion, our study reinforces the usefulness of multigene panel testing in breast cancer cases but specifically in those with triple negative subtype regardless family history.