BRCA1 and ovarian cancer: ESR1 mutations (10.3%) are emerging biomarkers with therapeutic significance in predicting resistance to aromatase inhibitors and informing treatment with novel endocrine therapies, such as elacestrant.17,18 In ovarian cancer, a high genomic LOH score (≥16%), which is a genomic signature of homologous recombination repair deficiency (HRD),19 was observed in 30.7%, inactivating BRCA1/2 alterations in 13.8%, and other predictive markers combined in ~5% of samples.