The purpose of this study is to determine whether detection of pepsinogen Ⅰand Ⅱ combined with Helicobacter pylori antibody, so-called ABC method , is fit on gastric cancer screening in community of Wuxi City.

Gastric cancer is the third largest cause of cancer related deaths in China with about 350 ,000 gastric cancer-related deaths by gastric cancer in 2012. The studies from Japan and Korea have found gastric cancer screening, especially of the mass population, reduces mortality from gastric cancer, but the data is seldom in China. The ways include radiographic and endoscopic screening, although those methods were shown to reduce gastric cancer mortality, and was recommended as gold standard for population-based screening by Japan and Korea, but many problems have been pointed out: A serious drawback is low uptake of the target population; fear for radiation exposure(0.6 mSv), swallowing unpleasantness due to the use of barium meal, accidental fall during the examination and constipation, causing rare but more serious complications such as intestinal obstruction or diverticulitis after examination may account for the reasons for this low uptake, endoscopic screening is labor-intensive, more costly per examination as complete disinfection of the scope is mandatory, and requires a large number of well-trained experienced endoscopists.

Serological method, so-called ABC method , has been useful as gastric cancer preliminary screening in some areas, such as China, Japan and Korea. The major reasons are attributed to its simplicity, safety (radiation-free, discomfort free), and cost-efficiency. The ABC method is a blood test to stratify the risk of gastric cancer using the combination of H. pylori antibody and pepsinogen I and II, that was documented by large-scale studies in Japan. But the data was short in China, especially in the community.

Inclusion Criteria:

Age 40-70 years old, men and women are not limited, and there are one of the following:

1. Hp infected.
2. Previously suffering from chronic atrophic gastritis, gastric ulcer, gastric polyps, hypertrophic gastritis, pernicious anemia and other precancerous diseases of the stomach.
3. First degree relatives of patients with gastric cancer.
4. Other risk factors for gastric cancer. (high salt, salted diet, smoking, heavy drinking, etc.)

Exclusion Criteria:

1. Severe heart, liver, kidney, dysfunction or mental disorders
2. History of gastric surgery (including surgery, minimally invasive EMR, ESD)
3. Use of PPI, acid preparation, stomach protecting agent in the first two weeks
4. The researchers considered inappropriate participants.
5. Informed consent cannot be attained