Used in targeted cancer therapy, particularly for HER2-positive breast and gastric cancers. Binds specifically to the HER2 receptor, blocking signaling pathways that drive tumor growth. Facilitates immune-mediated destruction of cancer cells through mechanisms like antibody-dependent cellular cytotoxicity (ADCC). Employed in diagnostic applications to detect HER2 overexpression in tumor tissues. Also serves as a reference standard in the development of biosimilars and other anti-HER2 therapeutic antibodies.