Background:

Gastric cancer is a leading cause of cancer deaths around the world. This disease is a serious problem in places like East Asia, Central and South America, and Eastern Europe. Researchers want to study the causes of gastric cancer and its precursors. They want to reduce the number of people with stomach cancer.

Objectives:

To learn more about bacteria factors and other causes of gastric cancer. To study potential markers associated with precancerous gastric lesions (intestinal metaplasia).

Eligibility:

Adults ages 40-70 years at certain hospitals in Chile who:

Are going to have upper gastrointestinal endoscopies

OR have stomach cancer and need surgery

Design:

Participants will give gastric tissue samples.

Some participants will donate a portion of the stomach tissue that is removed as part of their clinical care.

Participants will give access to reports of their stomach exam. They will allow researchers to photograph the microscope slides of their tissue samples.

Participants will answer questions. The topics of the questions include:

Age, height, weight

Education

Habits including tobacco and alcohol

Personal and family history of disease

Reproductive history

Diet

Some participants will give blood, urine, saliva, and stool samples. Study staff will collect the blood. They will tell the participants how to collect the other samples themselves.

The burden of gastric adenocarcinoma is unevenly distributed, with several Asian and Latin American countries having particularly high incidence rates. Although chronic infection with Helicobacter pylori is the primary cause of this cancer, environmental and host cofactors modify the course of infection and determine whether infected individuals develop cancer. Due to the lack of adequate screening strategies and consequent late diagnosis, trends in mortality are similar to incidence, making this neoplasia the third leading cause of cancer death worldwide. The International Agency for Research on Cancer predicts that there will be no reduction in gastric cancer cases until at least 2030 due to population growth and aging. H. pylori-related gastric carcinogenesis is a multi-step process and mucosal lesions of intestinal metaplasia (IM) and dysplasia confer increased risk of progression. Therefore, case-control studies of these premalignant lesions may provide insights into cancer etiology and inform risk stratification. In addition, biomarkers to identify high-risk individuals are needed for early detection and curative treatment. Accordingly, we propose a 3-year study of Chilean adults undergoing upper gastrointestinal endoscopy for clinical purposes to identify 600 subjects with advanced premalignant lesions (i.e., incomplete-type IM, complete-type IM with extension to gastric corpus and dysplasia) for informative comparisons with 600 controls with non-atrophic gastritis, a benign histologic change apparent in most H. pylori infected individuals. As an additional case group, 100 individuals with newly diagnosed gastric cancer will be recruited from the same clinics. This multidisciplinary project will simultaneously evaluate bacterial, host and environmental factors towards a better understanding of gastric cancer etiology that may guide future efforts for prevention and control. We will explore risk factors that have been insufficiently studied, such as various hormones, H. pylori genomics, non- H. pylori gastric microbiota, and other parasitic infections. We will also evaluate potential noninvasive screening markers, including pepsinogens, hormones, miRNAs and DNA methylation. Results from this study may lead to improved management recommendations for individuals with advanced IM. Additionally, the resulting biobank of gastric tissue, blood, urine, saliva and stool will enable state-of-the-art molecular assays and serve as a resource for future research in this area.

• INCLUSION CRITERIA:

Two groups of symptomatic patients aged 40 to 70 years old, who are long term residents of a high gastric cancer risk area:

• Approximately 1300 patients who need upper endoscopy (examination of the lining of the stomach with a flexible tube).
• Approximately 100 patients recently diagnosed with stomach cancer who need surgery as treatment for the disease.

EXCLUSION CRITERIA:

• Pregnant women
• Children

Patients attending gastroenterology services.