PARP1 and ovarian cancer: However, given that ovarian cancer cells often exhibit BRCAness (due to defects in homologous recombination) [46], [80], a phenotype that renders cells exquisitely sensitive to PARP inhibitors [81], it remained an unanswered question whether PARP inhibitors would also sensitize to FdUrd in colon cancer cells, which do not have defects in homologous recombination.