ERBB2 and melanoma: The conjugation to cell-penetrating peptides, such as tumor-targeting adaptor folic acid, has allowed for enhanced cellular uptake and elevated PTT effects [32]; conjugation to cell-targeting molecules, such as anti-HER2 and melanoma-associated antigen antibodies, allows for selective killing and uptake via melanoma cells [33,36]; conjugation to other antitumor therapies, such as betulin, has resulted in increased growth inhibition and the proliferation of melanoma cells in vitro [29].