Used in targeted cancer therapy, particularly for HER2-positive breast and gastric cancers. Binds specifically to the HER2 receptor, inhibiting tumor cell proliferation and promoting immune-mediated destruction of cancer cells. Employed in diagnostic applications to detect HER2 expression levels in tumor tissues, guiding treatment decisions. Also utilized as a reference standard in immunoassays and biosimilar development to ensure consistency and efficacy of anti-HER2 therapeutics.