Next, we sought to determine whether we could sensitise ovarian cancer cells to PARP inhibition by down-regulation of a key component of HR, specifically BRCA1. We chose two BRCA1 WT cell lines for this purpose, specifically OVCAR-3 with a known CCNE1 amplification frequently associated with HR proficiency [34], and A2780 that has been speculated to harbor a defect in DNA repair [35]. This evidence concerns the gene CCNE1 and ovarian cancer.