Missense Variants of Uncertain Significance: A Powerful Genetic Tool for Function Discovery with Clinical...

The breast cancer susceptibility gene BRCA2 encodes a multifunctional protein required for the accurate repair of DNA double-strand breaks and replicative DNA lesions. In addition, BRCA2 exhibits emerging important roles in mitosis. As a result, mutations in BRCA2 may affect chromosomal integrity in multiple ways. However, many of the BRCA2 mutations found in breast cancer patients and their families are single amino acid substitutions, sometimes unique, and their relevance in cancer risk remains difficult to assess. In this review, we focus on three recent reports that investigated variants of uncertain significance (VUS) located in the N-terminal region of BRCA2. In this framework, we make the case for how the functional evaluation of VUS can be a powerful genetic tool not only for revealing novel aspects of BRCA2 function but also for re-evaluating cancer risk. We argue that other functions beyond homologous recombination deficiency or "BRCAness" may influence cancer risk. We hope our discussion will help the reader appreciate the potential of these functional studies in the prevention and diagnostics of inherited breast and ovarian cancer. Moreover, these novel aspects in BRCA2 function might help find new therapeutic strategies.