BRCA1 and ovarian cancer: Epigenetic silencing of BRCA1 or RAD51C is a mechanism of homologous recombination deficiency in up to 5–30% of breast and ovarian cancers, with silencing of all BRCA copies (homozygous methylation) associated with improved PFS in response to rucaparib compared to BRCA1/2-intact cases [16].