Genomic instability in non–breast or ovarian malignancies of individuals with germline pathogenic variants in BRCA1/2

Individuals with germline pathogenic variants in BRCA1 or BRCA2 are at a high risk of breast and ovarian carcinomas with BRCA1/2 deficiency and homologous recombination deficiency that can be detected by analysis of genome-wide genomic instability features such as large-scale state transitions, telomeric allelic imbalances, and genomic loss of heterozygosity. Malignancies with homologous recombination deficiency are more sensitive to platinum-based therapies and poly(ADP-ribose) polymerase inhibitors. We investigated the fraction of non-breast or ovarian malignancies that have BRCA1/2 deficiency and genomic instability features.