We used an isogenic pair of BRCA1-deficient (HR-deficient) UWB1.289 vs. BRCA1-proficient (HR-proficient) UWB1.289+BRCA1 ovarian cancer cells (herein referred to as “UWB” and “UWB+BRCA1”) for constructing an in vitro model of PARPi resistance. This evidence concerns the gene BRCA1 and ovarian carcinoma.