Recently, to target poly(ADP-ribose) polymerase 1 (PARP1), researchers used E3 ubiquitin ligase murine double minute 2 (MDM2) ligand nutlin-3 derivative and PARP1 ligand niraparib derivative as a PROTAC, resulting in PARP1 degradation and apoptosis of human breast cancer cells MDA-MB-231 [35]. The gene discussed is PARP1; the disease is breast cancer.