Paclitaxel (Albumin-bound) Combined With Oxaliplatin and S-1 Conversion Therapy for Gastric Adenocarcinoma

Inclusion Criteria: * Age of 18-75 years; male or female. * Karnofsky Performance Status Score ≥70. * Histological diagnosis of gastric adenocarcinoma, HER2 expression negative. * The initial unresectable locally advanced or potentially resectable metastatic gastric adenocarcinoma, potentially resectable factor includes a single liver metastases, localized abdominal para-aortic lymph node (16a1 / b2) metastasis or positive abdominal free cancer cells. * Physical condition and organ function allow for larger abdominal surgery. * Subject baseline blood routine and blood biochemistry indexes meet the following criteria: hemoglobin(HB) ≥90 g/L; absolute neutrophil count(ANC) ≥1.5×109 /L; platelet count(PLT) ≥100×109 /L; alanine glutamate transaminase (ALT) and glutamate transaminase (AST) ≤2.5 x upper limit of normal range (ULN); total bilirubin (TBIL)≤1.5 x upper limit of normal range (ULN); Creatinine(Cr)≤1.5 x upper limit of normal range(ULN); Serum albumin≥30g/L. * Echocardiographic scan confirmed left ventricular ejection fraction (LVEF) ≥ 50%. * No serious accompanying disease lead to a survival period of \<5 years. * Agree and be able to follow the protocol during the study period. * Written informed consent was provided prior to the study screening and the patient was informed that the study could be withdrawn at any time during the study without any loss. Exclusion Criteria: * For the treatment of the gastric cancer, patients who have received cytotoxic chemotherapy, radiotherapy or immunotherapy, except corticosteroids. * Pregnancy or breastfeeding woman. * Women of childbearing age who had a positive pregnancy test at baseline or who did not undergo a pregnancy test. Menopausal women must be stopped for at least 12 months to ensure that no pregnancy is possible. * Men and women who have sex (with fertility probability) are reluctant to contraception during the study. * Patients with ascites and positive abdominal free cancer cells. * There are other history of malignant disease in the last 5 years, except for cured skin cancer and cervical carcinoma in situ. * Those with a history of epilepsy, central nervous system disease, or mental disorder may be judged by the investigator that their clinical severity may hinder the signing of informed consent or affect the patient's oral medication compliance. * Clinically severe (active) heart disease, such as symptomatic coronary heart disease, New York Heart Association (NYHA) class II or more severe congestive heart failure or severe drug-affected arrhythmias, or there is a history of myocardial infarction in the last 12 months. * Upper gastrointestinal stagnation or abnormal physiological function or malabsorption syndrome may affect the absorption of S-1. * It is known to have peripheral neuropathy ≥ NCI CTC AE grade 2. However, only the deep sputum reflex (DTR) disappears and the patient does not have to be excluded. * Organ transplantation requires immunosuppressive therapy. * Severe uncontrolled recurrent infections, or other serious uncontrolled concomitant diseases. * Moderate or severe renal impairment \[creatinine clearance equal to or lower than 50ml/min (calculated according to Cockcroft and Gault equations), or serum creatinine \> upper normal limit (ULN). * Those suffering from dihydropyrimidine dehydrogenase (DPD) deficiency are known. * Those who are allergic to taxanes or any research ingredients. * Those who received research medications or preparations/treatments (ie, participated in other trials) within 4 weeks prior to enrollment.