ERBB2 and cancer: A wide variety of targeted gold, silica, polymeric and liposomal nanoparticles [379–382] functionalized with antibodies (anti-EGFR, anti-HER2), lectins [383], folate molecules [384], peptides (tripeptide Arg–Gly–Asp (RGD) [385, 386], cyclic version of RGD, CRGDKGPDC (called iRGD) [387]), aptamers [388] and mannose [389] have been designed for selective cancer cell uptake with enhanced PDT efficacies.