PARP1 and ovarian cancer: PARP inhibitor‐resistant human pancreatic cancer cell lines were found to express new BRCA2 isoforms by an intragenic deletion of the c.6174delT frameshift mutation, which restored the open reading frame (ORF) of the BRCA2 gene and thus the ability to repair DSBs by HR repair.86, 87 The in vitro selection of a BRCA2‐mutated ovarian cancer cell line, which was sensitive to both platinum and PARP inhibition, by a cisplatin/PARP inhibitor combination led to the recovery of BRCA2 function induced by secondary BRCA2 mutation.