High-Throughput Functional Evaluation ofBRCA2Variants of Unknown Significance

ABSTRACT Numerous nontruncating missense variants of the BRCA2 gene have been identified, but there is a lack of convincing evidence, such as familial data, demonstrating their clinical relevance and they thus remain unactionable. To assess the pathogenicity of variants of unknown significance (VUSs) within BRCA2 , we developed a novel method, the MANO-B method, for high-throughput functional evaluation utilizing BRCA2 -deficient cells and poly(ADP-ribose) polymerase (PARP) inhibitors. The estimated sensitivity and specificity of this assay compared to those of the International Agency for Research on Cancer (IARC) classification system were 95% and 95%, respectively. We classified the pathogenicity of 186 BRCA2 VUSs with our original computational pipeline, resulting in the classification of 126 mutations as “neutral/likely neutral”, 23 as “intermediate”, and 37 as “deleterious/likely deleterious”. We further invented a simplified, on-demand annotation system, the Accurate BRCA Companion Diagnostic (ABCD) test, as a companion diagnostic for PARP inhibitors in patients with unknown BRCA2 VUSs. The ABCD test classification was reproducible and consistent with that of a large-scale MANO-B method.