Based on the detection technology of methylation sites in feces, combined or not combined with Helicobacter pylori gastric cancer susceptibility gene detection, an early diagnosis and detection system for gastric cancer is established, and the clinical diagnostic value of the detection system is evaluated. In addition, the study observed the association between different loci and post-treatment recurrence, metastasis, or long-term survival rate through long-term follow-up of gastric cancer patients; Follow up with individuals with benign diseases such as gastritis and healthy individuals, compare cases of gastric cancer, and compare their sample data during follow-up with controls who did not have the disease.

Inclusion Criteria:

1. Age ≥ 18 years old, male or female not limited.
2. Within 90 days, the gastroscopy and/or pathological results confirm the absence of gastric cancer.
3. Patients must be able to fully understand the informed consent form and be able to personally sign it.

Exclusion Criteria:

1. Severe heart, liver, kidney dysfunction, or mental illness.
2. History of malignant tumors in the upper gastrointestinal tract.
3. Pregnant women.
4. Those with unclear pathology.
5. Those with unsatisfactory sample retention (such as insufficient sample size).

Subjects for this clinical study were obtained from inpatients and outpatient follow-up patients attending the sub-center. Subjects will be identified by the investigator based on subject entry criteria and informed of the contents of the informed consent form. Subjects will have their feces collected at the time of clinic visit or at the time of physical examination and will be tested for fecal methylated DNA and H. pylori gastric cancer susceptibility genes.