BRCA1 and ovarian serous adenocarcinoma: However, our recent findings of low-level mosaic primary epimutations in the BRCA1 gene, affecting 5–9% of all females and being associated with an elevated risk of both triple-negative breast cancer and high-grade serous ovarian cancer [15, 16], focused on early-life events affecting a large fraction of the population, resulting in increased cancer risk.