Used in targeted cancer therapy, particularly for HER2-positive breast and gastric cancers. Binds specifically to the HER2 receptor, inhibiting cell proliferation and promoting immune-mediated destruction of cancer cells. Employed in diagnostic assays to detect HER2 overexpression and guide treatment decisions. Serves as a reference standard in the development of biosimilars and new anti-HER2 therapeutics. Also utilized in research settings to study HER2 signaling pathways and evaluate drug efficacy.