To characterize the changes leading to Olaparib resistance in breast cancer cells, we generated Olaparib resistance in Olaparib-sensitive BRCA1 mutant MDAMB436 and BRCA2 mutant HCC1428 cells by culturing them with increasing concentrations of PARPi (51, 52) (Fig. 1A). Here, BRCA1 is linked to breast cancer.