To evaluate the clinical efficacy of camrelizumab, apatinib Mesylate and nab-paclitaxel combined with oxplatin and S-1 in the neoadjuvant treatment of locally advanced gastric cancer with different genotypes
Age from 18 to 75 years, all sex；
Primary gastric adenocarcinoma (papillary, tubular, mucinous, signet ring cell, or poorly differentiated) confirmed pathologically by histology or cytology；
CT/MRI,PET-CT or laparoscopic exploration were used to confirm the diagnosis of gastric cancer staging as cT2-4a and/or N+ and M0 before operation.；
measurable lesions at least should be detected by CT/MRI examination in accordance with the RECIST1.1.（CT scan of tumor lesion length≥10mm，CT scan short diameter of lymph node≥15mm，scan slice thickness 5mm）;
Previous history of chemotherapy, radiotherapy, targeted drug therapy or immunotherapy
Patients with contraindications for surgical treatment and chemotherapy or whose physical condition and organ function do not allow for major abdominal surgery；
patients with metastasis；
Having any active autoimmune diseases or a history of autoimmune diseases (such as interstitial pneumonia, uveitis, enteritis, hepatitis, pituitary inflammation, vasculitis, myocarditis, nephritis, hyperthyroidism, hypothyroidism, including but not limited to these diseases or syndromes); Patients with vitiligo or cured childhood asthma/allergies who did not need any intervention in adulthood were excluded; Autoimmune hypothyroidism treated with a stable dose of thyroid replacement hormone; Type 1 diabetes with stable doses of insulin；
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Treatment groupsSee each treatment group below.