Serum pepsinogen (PG) levels are considered reliable markers for progression of atrophic gastritis with a stepwise reduction in the serum PG I level or PG I/II ratio. A combination of serum PG levels and Helicobacter pylori serology are used as a biomarker strategy for detection of individuals at increased risk of gastric neoplasm based on Correa's hypothesis. The investigators aimed to uncover whether this combination method could predict the risk of gastric neoplasms and the progression of chronic atrophic gastritis after 3 years. All the participants will be followed for an expected average of 3 years.

According to the Correa's hypothesis, the combination method using serum pepsinogen levels and serum Helicobacter pylori antibody would predict the risk and cell type of gastric neoplasm. However, in endemic regions of H. pylori infection such as in East Asian countries (Korea, Japan, and China), most of the aged population are have current or had past H. pylori infection. Therefore, in this study, we are going to uncover whether the risk of gastric neoplasm is significantly higher in the atrophy(+)/H. pylori(-) group followed by atrophy(+)/H. pylori(+), atrophy(-)/H. pylori(+), and atrophy(-)/H. pylori(-) groups. In addition, we are going to investigate whether those slow-growing gastric neoplasms such as differentiated gastric cancers with Lauren's intestinal type and gastric adenoma are more commonly developed in atrophy group following the Correa's hypothesis, whereas rapid-growing gastric neoplasms such as poorly-cohesive carcinoma or undifferentiated gastric cancers with Lauren's diffuse type are more commonly developed in the subjects without atrophy. Taken as a whole, our study result will provide an evidence whether this biomarker strategy are useful for the detection of individuals at increased risk of gastric neoplasm.

Inclusion Criteria:

• Korean adults older than 18 year-old
• Subjects who agreed on serum pepsinogen tests, H. pylori serology, and upper gastrointestinal endoscopy on the same day

Exclusion Criteria:

• Subjects who had past history of gastric surgery
• Abnormal endoscopic or laboratory finding that require further treatment
• Any evidence of malignancy other than gastric neoplasm

Asymptomatic Korean adults who underwent serum PG tests, H. pylori serology, and upper gastrointestinal endoscopy on the same day at our center.