The effect of onvansertib and olaparib on cell viability was tested in two human ovarian cancer cell lines: Ovcar-3 (TP53 loss, CCNE1 amplified and BRCA wt) and ES-2 (TP53 loss, BRCA wt, PALB2 mutated); in parental p53 deleted ID8 murine syngeneic cell lines (F3-BRCA1 wt- and F3-BRCA1−/−) and their corresponding olaparib-resistant cell lines (F3-OlaR and F3-BRCA1−/−OlaR), obtained in our laboratory [30]. This evidence concerns the gene BRCA1 and ovarian cancer.