BRCA1 and neoplasm: Subsequently, we found that PARP1 mediates the DNA repair ability of OXA resistance cells by regulating the DNA repair pathway BER, and after the combination of PARP1 inhibitor, Olaparib, the joint effect allowed the drugs to effectively cause homologous recombination failure through impaired CDK1 and BRCA1 function, eventually leading to tumor cell apoptosis.