PARP (poly ADP ribose polymerase) inhibitors such as olaparib, niraparib, rucaparib, and talazoparib have been approved by the United States Food and Drug Administration for use in breast and ovarian malignancies.73 However, their efficacy has also been studied in pancreatic and biliary tract cancers, as well as glioblastoma, lung, and prostatic cancers.143 PARP inhibitors trap PARP1 and PARP2 at DNA damage sites and prevent the recruitment of additional DNA repair proteins. The gene discussed is PARP1; the disease is biliary tract cancer.