Human epidermal growth factor receptor 2 (HER2), also known as ErbB2, is a type I membrane glycoprotein and belongs to the epidermal growth factor receptor family. HER2 itself does not have a ligand binding domain, so it cannot bind to growth factors. However, it tightly binds with other ligand binding members of the epidermal growth factor receptor family to form a heterodimer, which stabilizes ligand binding and enhances downstream signaling pathways mediated by kinases, such as mitogen activated protein kinase and phosphatidylinositol-3 kinase. HER2 is highly invasive in breast cancer. Nearly 30% of breast cancer showed a significant increase in HER2 gene or overexpression of protein produced by HER2 gene. Overexpression of receptors in breast cancer is closely related to disease recurrence and poor prognosis. HER2 is of great significance in regulating signal transduction and cell growth and differentiation in development, cancer, neuromuscular nodes. The HER2 produced by our company is a gene recombinant protein derived from mammalian cells, with high purity, good immunogenicity, and high biological activity.