Parmar et al. 65 utilized 14 characterized luciferized HGS-OC PDX models and revealed that 13 models were resistant to olaparib monotherapy, among which 4 models presenting BRCA1 mutation, and olaparib in combination with a checkpoint kinase 1 (CHK1) inhibitor prexasertib contributed to tumor inhibition in olaparib-resistant models. Here, CHEK1 is linked to neoplasm.