To elucidate the reasons underlying the association between PD-L1 expression and olaparib efficacy in gBRCA mutation subgroups and why the trend disappeared in the HRD-positive subgroup, we reviewed the demographics (Additional file 2: Tables S5, S6), pathology and extent of disease (Additional file 2: Tables S7, S8), and previously received anti-tumour therapies and responses (Additional file 2: Tables S9, S10) of PD-L1-positive and PD-L1-negative patients in gBRCA mutation and HRD subgroups. This evidence concerns the gene CD274 and neoplasm.