In this proposal the investigators aim to develop a commercial kit to be used in primary screening and non-invasive triage for early detection of gastric cancer. This kit will be cost-effective and more accessible to the general population. In addition, the investigators would like to expand our current patent already submitted to INAPI (National Institute for Intellectual Property) and propose royalties to biomedical diagnostic companies for the use of our product at international level.

Gastric cancer is the first cause of death in Chile and the second worldwide. Currently, no screening methods are available for early detection of gastric cancer at population level. The only available test is serum levels of pepsinogen I/II for gastric atrophy, a precursor lesion only for intestinal type with low risk to progress to gastric cancer. The investigators' previous work, supported by FONDECYT (National Council for Research and Technology) and FONIS (National Council for Research and Development of Human Health) both from the Government of Chile led us to discover a potential biomarker for early detection of gastric cancer, Reprimo, a tumor suppressor gene related to p53 in the arrest of G2-M of the cell cycle (Clin Cancer Res. 2008;14:6264-9). Here, the investigators propose to evaluate plasmatic detection of Reprimo in conjunction with gastric atrophy markers and H.pylori detection to establish a novel screening and triage strategy for early detection of gastric cancer. The aims are i) to determine sensitivity and specificity for Reprimo in the detection of gastric cancer in a high-risk population evaluated by upper gastrointestinal endoscopy (1,000 males, 30-74 y.o. low income, symptomatic or asymptomatic) and ii) to characterize at clinical, pathological and molecular level cases of gastric cancer identified and non-identified by direct detection of Reprimo along with atrophy, H.pylori and clinical markers. With this information, the investigators will develop an algorithm for screening and triage evaluating predictive values of plasmatic detection of Reprimo versus atrophy & H.pylori detection and clinical data in a general population (3,000 male/female, 40-70 y.o.) from a high-risk area for gastric cancer in Chile. In this step the investigators will evaluate also acceptability, efficacy and efficiency of the proposed algorithm. In this proposal the investigators aim to develop a commercial kit to be used in primary screening and non-invasive triage for early detection of gastric cancer. This kit will be cost-effective and more accessible to the general population. In addition, the investigators would like to expand the investigators' current patent already submitted to INAPI and propose royalties to biomedical diagnostic companies for the use of the investigators' product at international level.

Inclusion Criteria:

• Male or Female
• Age 40-70 y.o.

Exclusion Criteria:

• Gastric Cancer
• Dyspepsia
• Bleeding disorders

3000 population base study from rural area in south of Chile. This is area has one of the highest incidence of gastric cancer in the world (35/100.000).