• provide archive tumor tissue samples or accept fresh tumor tissue biopsy(Sample requirements are: formalin-fixed and paraffin-embedded wax blocks of tumor tissue or at least 20 unstained tumor specimen slides).

• assessed by the surgery can be removed, histology/confirmed HER2 positive cytology and the integration of a stomach esophagus carcinoma.

‣ CT2-4CN any C M0 or T any CN +M0, AJCC/UICC TNM staging of gastric cancer (8th edition).

⁃ The HER2 receptor protein status was assessed by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) using the following methods.Tumors with an IHC 3+ score are considered HER2-positive.Patients with immunohistochemical 2+ tumors were given FISH tests to determine FISH positive samples.

⁃ Abdominal computed tomography (CT), abdominal, pelvic, and/or echo-endoscopy were performed 2 weeks before surgery to assess resectability.

• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 or 2.

• have no received no any anti-tumor treatment, including surgery, chemotherapy, targeted therapy, immune therapy.

• Adequate organ function (No blood transfusion or hematopoietic stimulating factor therapy was received within 14 days. Absolute neutrophil count (ANC) ≥1.5×109/L Platelet count ≥75×109/L Hemoglobin ≥80 g/L. Serum total bilirubin ≤1.5×ULN. total bilirubin must be \<3×ULN) Prothrombin time/international normalized ratio (PT/INR) ≤1.5×ULN and activated partial thromboplastin time (aPTT) ≤1.5×ULN.Aspartate transaminase (AST) and alanine aminotransferase (ALT) ≤3×ULN. For subjects with liver metastases, AST and ALT must be ≤5×ULN for subjects with liver metastases. Creatinine clearance rate (Ccr) ≥50ml/min（according to the Cockcroft-Gault formula）. Urine protein qualitative≤1+ ;Or urinary protein qualitative ≥2+, 24 hours urinary protein \< 1g)