The use of trastuzumab for injection can be considered for gastric impression cell carcinoma. It is recommended that patients first need to undergo HER2 gene test to clarify the tumor-causing gene, and if the test result is positive, they can be treated with trastuzumab injection, which is a commonly used drug for cancer. Trastuzumab for injection is a recombinant DNA-derived humanized monoclonal antibody that can selectively act on the cellular site of growth factor receptor-2, or HER2, and is commonly used clinically for metastatic cancers with HER2 overexpression. However, targeted therapy is generally applicable to the treatment of advanced gastric cancer, and is generally not needed in the early and intermediate stages. Side effects of trastuzumab for injection include diarrhea, constipation, and dyspepsia, and it is contraindicated for those who are allergic to trastuzumab or other ingredients. In addition, the treatment of targeted drugs has certain risks, which requires patients to stay in regular hospitals and use drugs under the guidance of professional doctors, and do not take drugs on their own.