Laparoscopic Staging for Locally Advanced Gastric Cancer in Chinese Patients

Inclusion Criteria: * sign written informed consent form * age ≥ 18 years * pathologically confirmed gastric or GEJ adenocarcinoma * disease at clinical stage of locally advanced gastric cancer by CT/EUS(cT2+NanyM0) * No prior antitumor treatment is allowed, including chemotherapy, radiotherapy, immune therapy or target therapy * Adequate organ function as defined below: Hematologic ANC ≥ 1.5\*109/l Hemoglobin ≥ 9 g/dl Platelets ≥ 100\*109/l Hepatic Albumin ≥ 30g/l Serum bilirubin ≤ 1.5×ULN AST and ALT ≤ 2.5×ULN ALP ≤ 2.5×ULN TBIL ≤ 1.5×ULN Renal Serum Creatinine \< 1.5 ULN * KPS ≥ 70 * Adequate lung and heart function * Negative serum or urine pregnant test within 7 days prior to randomization for child-bearing age women * Sexually active males or females willing to practice contraception during the study until 30 days after end of study. Exclusion Criteria: * Refuse to provide blood/tissue sample； * With distant metastasis diagnosed by CT/EUS； * Sexually active males or females refuse to practice contraception during the study until 30 days after end of study. * History of organ transplantation（including autologous bone marrow transplantation and Peripheral stem cell transplantation）； * Prior long term steroid therapy (excluding short term steroid treatment which is completed prior to \> 2 weeks of study enrollment)； * Patients with central nervous system(CNS) disorder or peripheral nervous system disorder or psychiatric disease； * Concurrent severe infection； * Concur…