Compare with the gastric cavity without cancerous transformation in atrophic gastritis, analyze the microbiota and metabolomics changes in intestinal type of gastric cancer under the background of atrophic gastritis, and explore the relevant mechanisms.

This study adopts a prospective cohort study. The expected recruitment time for all participants is 6 months, and all cases are cases who would receive magnifying endoscopy examination. The extent of atrophy and the presence of early gastric cancer are determined under magnifying endoscopy. Cases are chose into the gastric cancer group and atrophic gastritis group in a 1:1 ratio. There are 16 cases of intestinal type of gastric cancer under the background of atrophic gastritis, and 16 cases of atrophic gastritis without gastric cancer matched according to gender, age, and degree of gastric atrophy, totaling 32 cases. Analyze the characteristics of early gastric cancer under endoscopy, investigate the changes in microbiota and metabolomics of intestinal type of gastric cancer under the background of atrophic gastritis, and explore the relevant mechanisms.

Inclusion Criteria:

• •Intestinal type of gastric cancer or atrophic gastritis

  • Underwent Endoscopic submucosal dissection（ESD）

Exclusion Criteria:

• • have simultaneously other cancer

  • have severe systemic inflammatory disease ,serious illness such as diabetes, chronic lung diseases

We underwent magnifying staining endoscopy examination in our hospital and diagnosed cases of atrophic gastritis with or without gastric cancer under endoscopy.