Therefore, this research aims to investigate the impact of HER2 on proliferation, chemotherapy resistance, invasion, and tumorigenicity of GCSCs, which might shed a light on further elucidating the mechanism on how GCSCs regulate self-renewal, invasion, and tumorigenicity and show the theoretic basis of anti-tumor comprehensive therapies targeting HER2 signal pathway of GCSCs. The gene discussed is ERBB2; the disease is neoplasm.