ERBB2 and neoplasm: The latter provides theinteraction of the multimodal protein with tumors overexpressingtumor-associated antigen HER2 (human epidermal growth factor receptor type II).In vitro experiments in a 2D monolayer cell culture and a 3Dspheroid model have confirmed HER2-specific photo-induced cytotoxicity of thesystem without the use of an external light source; in addition, experiments inanimals with subcutaneous HER2-positive tumors have shown selectiveaccumulation of DARP-NanoLuc-SOPP3 on the tumor site.