Used in targeted cancer therapy, particularly for HER2-positive breast and gastric cancers. Binds specifically to the HER2 receptor on cancer cells, blocking signaling pathways that drive tumor growth and promoting immune-mediated destruction of the cells. Employed in diagnostic assays to confirm HER2 overexpression, guiding treatment decisions. Also utilized in research settings to study HER2 receptor function and evaluate new therapeutic strategies. Its high specificity makes it valuable in immunohistochemistry, flow cytometry, and as a reference standard in antibody development.