The study flow chart of case recruitment to screen
infection. In total, 389 family relatives (GCF) from 195 non-cardiac gastric cancer (GCA) index patients, including different familial relations, were enrolled. Blood sampling for DNA extraction and H. pylori screening with the urea breath test (UBT) were performed in all 389 GCF. There were also 143 of 173 duodenal ulcer patients to receive blood sampling and H. pylori screening. The differences in single nucleotide polymorphisms (SNPs) were compared between the DNA of 195 GCA children and 143 duodenal ulcer controls. Of the 88 H. pylori-infected children of GCA, 56 received endoscopy and topographical biopsies to assess whether the corpus predominant gastritis index (CGI), atrophy (AT), spasmolytic polypeptide expressing metaplasia (SPEM) and intestinal metaplasia (IM) correlated to the SNPs of ITGA5, ITGB1, IL-10, COX-2, RUNX3, and TFF2 identified from the comparison between the children of GCA and the duodenal ulcer controls.