In this study, we aim to establish a prospective cohort of patients with endoscopically and histologically confirmed intestinal metaplasia, collect gastric mucosal tissue samples from this cohort, and follow the development of gastric cancer over time.

Patients visiting Seoul National University Hospital, who have previously received an incidental diagnosis of intestinal metaplasia during a prior gastroscopy examination, will be considered as potential candidates for this study. Upon obtaining their informed consent to participate, the initial endoscopy procedure will involve the collection of biopsies to ensure an accurate histological diagnosis of intestinal metaplasia. These biopsies will be taken from the antrum and body of the stomach, according to the protocol of the updated Sydney system, to pathologically diagnose the extent and severity of intestinal metaplasia. One to two pieces of tissue remaining from this diagnostic process will be retained for future analysis. Subsequently, patients will be followed up on an outpatient basis to track the development of gastric cancer through routine screening endoscopies. In cases where patients develop gastric cancer, a comparative analysis will be conducted with those who do not develop gastric cancer, to determine the differences in expression of markers in the gastric mucosal tissue that was collected during the initial endoscopy. Our ultimate aim is to identify potential biomarkers that may serve as predictive indicators for the development of gastric cancer in patients with a preexisting diagnosis of intestinal metaplasia.

Inclusion Criteria:

• Patients who visit Seoul National University Hospital
• Patients who have been visually diagnosed with intestinal metaplasia at a prior exam

Exclusion Criteria:

• Patients who have been previously diagnosed with gastric cancer or adenoma
• Patients who have previously received gastrectomy

Outpatient clinic visitors