Used in research and development for targeted cancer therapies, particularly in breast and gastric cancers overexpressing HER2. Serves as an antigen for antibody screening and characterization during the development of monoclonal antibodies like trastuzumab and pertuzumab. Employed in immunoassay development, including ELISA and flow cytometry, to detect anti-HER2 antibodies or evaluate binding affinity of therapeutic candidates. Supports structural and functional studies to understand HER2 signaling mechanisms. The His tag facilitates easy purification and detection, making it valuable in protein-protein interaction studies and diagnostic applications.