PARP1 and cancer: Decreased PARP1 activity is explained by the ability of the complexes to bind the zinc‐finger motif of PARP1, ejecting zinc and inactivating the enzyme in the process (Figure 12b).[151, 152] Although [Au(phen)Cl2]Cl, [Au(bipy)Cl2]Cl and derivatives display greater PARP1 inhibitory effects than olaparib and exhibit cytotoxicity in several cancer cell lines,[153] their specificity towards BRCA‐deficient cancer cells or ability to synergise with DNA‐damaging agents or ionising radiation is unknown at present.