I. Relationship between gastric cancer and environment and diet: The incidence of gastric cancer has a certain relationship with environmental factors. The incidence rate of stomach cancer is higher in high latitude areas. The incidence rate of stomach cancer is also higher among residents living in peat soil areas than those living in sandy or clay soil areas. Residents living in coal or asbestos mining areas have a significantly higher incidence of stomach cancer. The ratio of zinc and copper content in soil is also related to the incidence rate of stomach cancer. The incidence rate of stomach cancer in the northern and southeastern coastal provinces of China is also much higher than that in the southern or southwestern provinces. Smoked, salted and fungus-contaminated foods are related to the occurrence of stomach cancer. The relationship between stomach cancer and heredity: Stomach cancer is not contagious and there is no direct evidence of heredity, but there is a phenomenon that stomach cancer gathers in a few families (non-contagious, only because the family has the same or similar living and dietary habits); stomach cancer is related to blood type; stomach cancer is related to blood type, and the incidence rate is much higher than that in the south or southwest of China. There is a certain relationship between stomach cancer and blood type: the risk of stomach cancer in people with blood type A is 20-30% higher than that of other blood types. All these indicate that heredity is related to stomach cancer. However, most scholars are cautious and think that there is not enough evidence. High-risk groups of stomach cancer: It should be said that the exact cause of stomach cancer is not very clear. However, it is known that stomach cancer is related to some benign diseases of stomach, which are what we usually call “stomach diseases”, such as gastric ulcer, atrophic gastritis, gastric polyp, residual stomach (i.e., stomach remaining after surgery for benign gastric diseases), and the stomach cancer occurring in the residual stomach is what we call residual stomach cancer. Gastric cancer is also related to some precancerous lesions of the stomach, such as anomalous hyperplasia (also known as atypical hyperplasia), intestinal hyperplasia, etc. Helicobacter pylori (Hp) infection is related to the occurrence of gastric cancer to a certain extent. Early diagnosis of gastric cancer is the key to improve the therapeutic effect of gastric cancer. However, according to the data in China, only one-fifth of the patients are diagnosed within three months after the symptoms of gastric cancer appear, and another one-fourth of the patients are diagnosed more than one year after the symptoms appear. Therefore, among the patients hospitalized for gastric cancer, only about 15% of them are stage I and II gastric cancer patients. Therefore, those who have the following conditions should be highly alert: over 0 years old with discomfort or pain in the middle and upper abdomen without obvious rhythmicity and accompanied by obvious loss of appetite and emaciation; patients with gastric ulcers, whose symptoms do not get better after strict medical treatment; patients with chronic curative gastritis accompanied by intestinal epithelial metaplasia and atypical hyperplasia, who have failed to get better after medical treatment; patients with gastric polyps >2cm as shown in X-ray; patients who are middle-aged or above, who have unexplained anemia, emaciation and fecal loss; patients who are middle-aged or above, who are in the middle and above, who are in the middle and above. Unexplained anemia, wasting and persistent positive fecal occult blood.