In 1965, Lauren divided gastric cancer into two main types according to pathology: intestinal type and diffuse type. munoz and his colleagues made extensive observations on the distribution of both types of gastric cancer in Colombia, Herzegovina, Israel, Poland, Hungary and the United States and found that the intestinal type was predominant in areas with high incidence of gastric cancer, mostly in men and in the older age groups. In contrast, the diffuse type predominated in the low incidence area, and this type was common in the lower age groups. Subsequently, correa et al. examined the relationship between this pathological typing and immigration, comparing Japanese residents of miyagi with Japanese immigrants in Hawaii, and found that the incidence of diffuse gastric cancer was similar in Japanese from both areas, while the incidence of intestinal gastric cancer was different, with the latter being significantly lower than the former. It was suggested that the decrease in gastric cancer incidence among Japanese immigrants was mainly due to the decrease in the incidence of intestinal type gastric cancer. munoz and aswall analyzed different types of gastric cancer in Norway during three periods and showed that intestinal type gastric cancer decreased rapidly over time, while diffuse type decreased slowly. A similar study conducted by hanai et al. in Japan yielded the same results. It has been hypothesized that intestinal gastric cancer is closely related to environmental factors. In China, it has also been reported that intestinal type gastric cancer tends to occur in high incidence areas and diffuse type tends to occur in low incidence areas. However, there are also reports that the incidence rates of both types of gastric cancer in high and low incidence areas are similar. Intestinal gastric cancer is often associated with atrophic gastritis and epithelial hyperplasia of gastric mucosa, and its development is related to environmental factors. Diffuse gastric cancer is usually not accompanied by atrophic gastritis and gastric mucosal epithelial metaplasia, and is more closely related to genetic factors. Intestinal type gastric cancer originates from intestinal metaplasia mucosa, generally has obvious glandular structure, tumor cells are columnar or rectangular, brush border can be seen, tumor cells secrete acidic mucus material, similar to the structure of intestinal cancer; often accompanied by atrophic gastritis and intestinal metaplasia, mostly seen in elderly men, longer course, higher incidence and better prognosis. Diffuse gastric cancer originates from the intrinsic mucosa of the stomach, with poorly differentiated cells that grow diffusely and lack cellular junctions, and generally do not form glandular ducts; many low-differentiated adenocarcinomas and indolent cell carcinomas belong to this type; it is mostly seen in young women, prone to lymph node metastasis and distant metastasis, and has a poor prognosis. While the incidence of diffuse gastric cancer showed a decreasing trend in the same population, the incidence of diffuse gastric cancer increased from 0.3/100,000 in 1978 to 1.8/100,000 in 2000, with the most pronounced increase in indolent cell carcinoma. The Lauren typing reflects not only the biological behavior of the tumor, but also its etiology, pathogenesis and epidemiological features. Lauren typing is concise and effective, and is often used in Western countries. However, 10% to 20% of cases have features of both intestinal and diffuse types, which are difficult to be classified into either one of them, thus called mixed type.