FS102 is an Fc fragment antigen-binding protein targeting HER2, with a dissociation constant (KD) of 0.8 nM. FS102 promotes the degradation of HER2, activates Caspase3/7, disrupts cell membrane integrity, and induces apoptosis in tumor cells. FS102 shows potential for research in breast cancer, gastric cancer, and colorectal cancer.