Germline reflex BRCA1/2 testing following tumor-only comprehensive genomic profiling: why, when, and how.

The majority of tumor comprehensive genomic profiling (CGP) currently does not include a matched normal control. The use of a tumor-only CGP approach needs the development of a strategy to refine germline pathogenic/likely pathogenic variants (gP/LPVs) calls, so as to limit the performance of unnecessary germline reflex tests and instead successfully identify patients who are carriers of likely gP/LPVs. Guidelines have been developed for the identification of gP/LPVs in BRCA1/2 genes on the basis of tumor-only CGP results and for the evaluation of the appropriateness of performing germline reflex BRCA1/2 testing. In this study, an algorithm to assist decision-making for germline reflex testing of BRCA1/2 variants following tumor-only CGP is proposed.