Olaparib as the most representative of PARP1 inhibitors interferes with BER pathway and subsequently leads to the accumulation of unrepaired SSBs, which provoke collapsed replication forks in S phase, formatting the deleterious DSB.27 In the cells with defective HR, the DSB resulted from Olaparib can be either repaired by more error‐prone DNA repair mechanisms such as NHEJ or remain unrepaired, leading to synthetic lethality.28, 29 It has been approved as an anticancer drug for treatment in ovarian and BRCA mutated cancers. Here, PARP1 is linked to cancer.