2014-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/702062Background: Helicobacter pylori is believed to be the most important pathogen of gastric cancer. However, recent new sequencing-based methods, rather than culture-based methods, have found a broader variety of stomach microbiota in addition to H. pylori. The roles of these non-H. pylori bacteria in the gastric carcinogenesis remain unclear. Aims: 1. Systematically compare the stomach microbiome of patients with normal stomach, intestinal metaplasia, and gastric cancer 2. Examine the interactions between host and environmental factors, H. pylori and other non-H. pylori microbiome and patients’ clinical characteristics 3. Investigate how H. pylori and other non-H. pylori bacteria impact on cell biology of gastric cancer cells and explore the potential signaling pathways involved Study subjects and methods: Stomach microbiome study: 1. Collecting gastric tissue specimens from patients with normal stomach, with intestinal metaplasia, and those with gastric cancer 2. The collected gastric tissue specimens will be tested by pyrosequencing of 16s rRNA amplicons targeting the V1-V3 regions 3. The data of the pyrosequencing will be analyzed with alpha-diversity, phyla and genera distribution, clustering analysis, heatmap analysis, principle coordinate analysis, etc. 4. Examine H. pylori genotyping and culture H. pylori from the collected gastric tissue specimens for further in vitro study Host and environmental factor study: 1. Standardized questionnaire to survey host factors, including patients’ demographic data, previous comorbidities, and family history 2. Standardized questionnaire to survey environmental factors, such as PPI and antibiotics use, probiotics consumption, and diet preference 3. Examine the interactions between host and environmental factors, H. pylori and other non-H. pylori microbiome and patients’ clinical characteristics In vitro studies: 1. Establish functional analysis model in gastric caner cell culture system 2. Investigate how H. pylori and other non-H. pylori bacteria impact the cell biology of gastric cancer cells 3. Explore the potential signaling pathways involved in the above cell biology induced by H. pylori and other non-H. pylori bacteria Expected contributions: This project will provide valuable results for scientists who are interested to explore the stomach microbiome and its relationship with H. pylori, other host and environmental factors. It also provides physicians a new approach to understand gastric carcinogenesis. For patients, these observations may be useful for developing chemoprevention by modulating stomach microbiome.gastric cancerintestinal metaplasiaHelicobacter pylorimicrobiomesignal transduction