So far, numerous PARP1 inhibitors have been experimentally utilized for BRCA1/2-deficient cancer treatment, such as 3-aminobenzamide (3-AB), 1,5-dihydroxyisoquinoline (ISQ), 8-hydroxy-2-methylquinazolinone (NU1025) or 1-(4-dimethylaminomethyl-phenyl)-8,9-dihydro-7H-2,7,9a-benzo[cd]azulen-6-one (AG14361) (224). This evidence concerns the gene PARP1 and cancer.