Gastric cancer originates from mucosal epithelial tissue, which is a superficial tissue, and the specific pathological characteristics are as follows: 1. Classification of pathological types: divided into adenocarcinoma, adenosquamous carcinoma, squamous carcinoma, and carcinoid carcinoma, of which adenocarcinoma pathological tissue types account for 90%, and adenocarcinoma is subanalyzed and divided into papillary adenocarcinoma, tubular adenocarcinoma, indolent cell carcinoma, and undifferentiated adenocarcinoma; 2. Early gastric cancer: occurs relatively early, and clinical manifestations are not specific, commonly ulcerative gastrointestinal Clinical manifestations, such as vague pain in the upper abdomen, belching, abdominal distension, etc.; 3. Progressive gastric cancer: combined with more obvious abdominal pain and loss of appetite, with further growth of tumor, it will manifest corresponding clinical manifestations, such as proximal cardia position, difficulty in swallowing and choking sensation when eating; distal gastric tumor near the pylorus, obvious obstructive manifestations of abdominal distension, if combined with tumor bleeding, vomiting blood or black stool symptoms.