GRP and prostate cancer: Another example of functionalizing AuNPs via thiol groups of cysteine was provided by Torres–Garcia et al., who evaluated the in vitro potential of 99mTc-labeled and 177Lu-labeled AuNPs conjugated to Tat(49–57)-Lys3-bombesin peptides (99mTc/177Lu-AuNP-Tat-BN) as a plasmonic photothermal therapy and targeted radiotherapy system in PC3 prostate cancer cells [14].