PROS1 and cancer: Gold nanoparticles can deliver drugs to intracellular spaces to highly enhance the efficacy against tumor cells,98 for instance, high efficacy of PEGylated gold nanorods (PEG‐GNRs) on reversing MDR cancer cells has been identified.99 For another example, the platinum (IV) prodrugs conjugated GNRs can evade the deactivation of overexpressed detoxification proteins including metallothionein and GSH in A549R cells, and for restoration of the drug sensitivity in cisplatin‐resistant cancer cells.