GFP-Fragment Reassembly Screens for the Functional Characterization of Variants of Uncertain Significance in Protein Interaction Domains of the <i>BRCA1</i> and <i>BRCA2</i> Genes

Genetic testing for <i>BRCA1</i> and <i>BRCA2</i> genes has led to the identification of many unique variants of uncertain significance (VUS). Multifactorial likelihood models that predict the odds ratio for VUS in favor or against cancer causality, have been developed, but t...

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Bibliographic Details
Main Authors: Laura Caleca, Mara Colombo, Thomas van Overeem Hansen, Conxi Lázaro, Siranoush Manoukian, Michael T. Parsons, Amanda B. Spurdle, Paolo Radice
Format: Article
Language:English
Published: MDPI AG 2019-01-01
Series:Cancers
Subjects:
Online Access:https://www.mdpi.com/2072-6694/11/2/151
Description
Summary:Genetic testing for <i>BRCA1</i> and <i>BRCA2</i> genes has led to the identification of many unique variants of uncertain significance (VUS). Multifactorial likelihood models that predict the odds ratio for VUS in favor or against cancer causality, have been developed, but their use is conditioned by the amount of necessary data, which are difficult to obtain if a variant is rare. As an alternative, variants mapping to the coding regions can be examined using in vitro functional assays. BRCA1 and BRCA2 proteins promote genome protection by interacting with different proteins. In this study, we assessed the functional effect of two sets of variants in <i>BRCA</i> genes by exploiting the green fluorescent protein (GFP)-reassembly in vitro assay, which was set-up to test the BRCA1/BARD1, BRCA1/UbcH5a, and BRCA2/DSS1 interactions. Based on the findings observed for the validation panels of previously classified variants, BRCA1/UbcH5a and BRCA2/DSS1 binding assays showed 100% sensitivity and specificity in identifying pathogenic and non-pathogenic variants. While the actual efficiency of these assays in assessing the clinical significance of BRCA VUS has to be verified using larger validation panels, our results suggest that the GFP-reassembly assay is a robust method to identify variants affecting normal protein functioning and contributes to the classification of VUS.
ISSN:2072-6694