Treatment outcomes of anti-HER2 therapy in 11 patients with unresectable metastatic GC was evaluated.<h4>Results</h4>ERBB2 AMP (≥ 2.5-fold change) was detected by the targeted tumour sequencing test in 15 patients (9.9%), and HER2 positivity (IHC 3 + or IHC 2+/FISH positive) was detected in 21 patients (13.8%). The gene discussed is ERBB2; the disease is neoplasm.