Camrelizumab Combined With FOLFOX Neoadjuvant Therapy for Resectable Gastric and Gastroesophageal Junctional Adenocarcinoma

Inclusion Criteria: 1. 18-73 years old; male or female 2. confirmed gastric and gastroesophageal junction adenocarcinoma by Gastroscopic biopsy histopathological examination 3. Imaging (CT/MRI) and ultrasound gastroscopy confirmed: cT ≥ T2 and / or regional lymph node positive (N +); 4. ECOG score: 0\~2 points; 5. Expected survival period ≥ 12 weeks; 6. A histological specimen can be provided for secondary testing; 7. The main organ function meets the following criteria within 7 days before treatment: Blood routine examination criteria (without blood transfusion within 14 days): Hemoglobin (HB) ≥ 90g / L; The absolute value of neutrophils (ANC) ≥ 1.5 × 109 / L; Platelet (PLT) ≥ 80 × 109 / L (2) Biochemical examinations must meet the following criteria: Total bilirubin (TBIL) ≤ 1.5 times the upper limit of normal (ULN); Alanine aminotransferase (ALT) Aspartate aminotransferase (AST) ≤ 2.5 \* ULN; serum creatinine (Cr) ≤ 1.5 \* ULN or creatinine clearance (CCr) ≥ 60ml / min; (3) Doppler ultrasound assessment: left ventricular ejection fraction (LVEF) ≥ normal low limit (50%). 8. Women of childbearing age should agree to use contraceptives (such as intrauterine devices, contraceptives or condoms) during the study period and within 6 months after the end of the study; negative serum or urine pregnancy test within 7 days prior to study enrollment and must be non-lactating patients; men should agree to patients who must use contraception during the study period and within 6 months after the end of the study period. 9. The patient volunteered to participate in the study and signed an informed consent form; Exclusion Criteria: 1. Exceeding or currently suffering from other malignant tumors within 5 years, except for cervical cancer in situ, non-melanoma skin cancer and superficial bladder tumors \[Ta (non-invasive tumor), Tis (in situ carcinoma) And T1 (tumor infiltrating basement membrane)\]; 2. Patients with a high risk of bleeding or fistula due to the apparent invasion of adjacent organs (aorta or trachea); 3. Before starting treatment， subject administrated corticosteroids (day\> 10 mg equivalent dose prednisone), or other immunosuppressive drugs for systemic treatment of a disease within 14 days . In the absence of active autoimmune disease, \>10 mg of daily prednisone equivalent dose of inhaled or topical steroid and adrenal replacement steroid doses are permitted; 4. Anyone who has received any anti-tumor treatment in the past; 5. Significantly malnourished patients. Exclusion is performed if the patient is receiving intravenous fluids or is required to be hospitalized for continuous infusion therapy. Patients with good nutrition control ≥ 28 days can be enrolled before randomization; 6. Participants who received live/attenuated vaccine within 30 days of the first treatment; 7. Unresolved toxicity due to any previous treatment above CTC AE4.0 Level 2, excluding neurotoxicity of ≤2 caused by hair loss and oxaliplatin; 8. Allergic reactions and adverse drug reactions: 1. a history of allergies to the ingredients of the study drug; 2. contraindications to any study drug (fluorouracil or oxaliplatin) in the chemotherapy regimen. 9. Patients with any severe and/or uncontrolled disease, including: 1. patients with hypertension who are not well controlled by antihypertensive drug (systolic blood pressure ≥150 mmHg, diastolic blood pressure ≥100 mmHg); 2. with grade I or higher myocardial ischemia or myocardial infarction, arrhythmia (including QTc ≥ 480ms) and ≥ grade 2 congestive heart failure (New York Heart Association (NYHA) classification); 3. Severe or uncontrolled disease or active infection (≥CTCAE grade 2 infection), which the investigator believes may increase the risk associated with study participation, study drug administration, or affect the subject's ability to receive study medication; 4. Renal failure requires hemodialysis or peritoneal dialysis; 5. a history of immunodeficiency, including HIV-positive or other acquired, congenital immunodeficiency disease, or a history of organ transplantation; 6. Patients with diabetes who have poor glycemic control (fasting blood glucose (FBG) \> 10 mmol/L); subjects with active, known or suspected autoimmune diseases. Subjects with type 1 diabetes, residual hypothyroidism caused by autoimmune thyroiditis requiring hormone replacement therapy, and skin diseases that do not require systemic treatment (such as vitiligo, psoriasis or alopecia) can be enrolled; 7. patients with seizures and requiring treatment; 8. The subject has an interstitial lung disease that is symptomatic or may interfere with the discovery or management of suspected drug-related lung toxicity; previous and current subjects with a history of pulmonary fibrosis, interstitial pneumonia, pneumoconiosis, radiation pneumonitis, drug-associated pneumonia, severe impaired lung function, etc. that may interfere with the detection and management of suspected drug-related lung toxicity; 10. Patients with gastrointestinal diseases such as intestinal obstruction (including incomplete intestinal obstruction) or those who may have caused gastrointestinal bleeding, perforation or obstruction; 11. Patients who underwent surgical treatment, incisional biopsy or significant traumatic injury within 28 days prior to enrollment; 12. In the 4 weeks prior to enrollment, patients with any bleeding event ≥ CTCAE 3 have unhealed wounds, ulcers or fractures; 13. Overactive/venous thrombosis events within 3 months, such as cerebrovascular accidents (including transient ischemic attacks), deep static Pulmonary thrombosis and pulmonary embolism; 14. Prepare or accept previous allogeneic or allogeneic bone marrow transplantation, including liver transplantation; 15. According to the investigator's judgment, there is a concomitant disease that seriously harms the patient's safety or affects the patient's completion of the study; 16. Cannot perform biopsy to provide histological specimens; 17. those who have a history of psychotropic substance abuse and are unable to quit or have a mental disorder; Prepare or accept previous allogeneic or allogeneic bone marrow transplants, including liver transplants; 18. Urine routine showed urinary protein ≥ 2+ and confirmed 24-hour urine protein quantitation \> 1.0 g; 19. Patients with brain metastases; 20. Patients who have participated in other clinical trials of anti-tumor drugs within four weeks.