The gwLOH biomarker separated samples in the evaluation set with BRCA1/2 biallelic loss from samples with no evidence of mutations in BRCA1/2 or a subset of HRR genes with 100% sensitivity and 96.3% specificity in breast and with 92.1% sensitivity and 100% specificity in ovarian cancer (Fig. 2B). This evidence concerns the gene BRCA1 and ovarian cancer.