Helicobacter Pylori Genome Project (HpGP)

Overview

Helicobacter pylori is a common bacterial infection. It can lead to severe stomach problems, including stomach cancer. Researchers want to look at samples of the bacteria. These H. pylori strains will be taken from chronically infected people. They want to identify the genetic and epigenetic differences in H. pylori strains. This could help predict which people who get infected with the bacteria will get stomach cancer. This could lead to the cancer being detected earlier. It could also mean less people get stomach cancer. Objectives: To study genetic variations of H. pylori strains based on samples from chronically infected people. To identify the features of strains that might lead to severe stomach problems or stomach cancer. Eligibility: People ages 30-70 years who need an upper endoscopy or who were recently diagnosed with stomach cancer Design: Participants will be screened by the doctor who does their procedure and a study nurse. Participants who have endoscopy will have \~6 biopsies removed. These are tissue samples. They are about the size of a grain of rice. Participants will allow the study team to access reports from their stomach exam. Participants with stomach cancer will donate some of the tissue that will be removed during their clinical care. They will allow the study team to access reports of their surgery. They will also allow them to access the microscope slides of their stomach.

Helicobacter pylori, a Gram-negative bacterium associated with a spectrum of benign and malignant gastric conditions, is one of the most genetically variable pathogens. Variations in a few genes have been associated with risk of inflammation and carcinogenesis, but to date no systematic study has evaluated the entire bacterial genome. We propose a multicountry study to establish and analyze an informative international collection of H. pylori clinical isolates from residents of defined geographic areas. Molecular characterization will be conducted at the NCI/DCEG. Our hypothesis is that genetic and epigenetic variations in H. pylori strains among chronically infected individuals may affect risk of progression to gastric cancer. Findings from this study may help to characterize the differential virulence among H. pylori isolates and suggest predictive biomarkers for early diagnosis of cancer. The bacterial isolates and databases from this study will also provide a foundation for further elucidation of H. pylori pathogenesis.