Helicobacter pylori strain and the pattern of gastritis among first-degree relatives of patients with gastric carcinoma.

Background. Relatives of gastric cancer patients have an increased risk of gastric cancer, possibly related to genetically-related strains of Helicobacter pylori or a common environment. Methods. The pattern of gastritis and H. pylori from gastric cancer patients and their first-degree relatives were compared using detailed DNA fingerprints and vacA, cagA, and iceA genotyping. Results. Sixteen index cases from Korea, the US, or Colombia and their 38 first-degree relatives (brothers, sisters, sons and daughters) were studied. No definite, or consistent, relationship between the pattern of gastritis and the relatedness of the H. pylori strain was observed (i.e. relatives could have an identical or a totally different pattern of gastritis regardless if they were infected with identical or highly similar organisms). For example, three elderly siblings of an index case with atrophic pangastritis had identical H. pylori isolates and environments in childhood and yet two had antral predominant nonatrophic gastritis, which is typically associated with duodenal ulcer instead of gastric cancer. Conclusions. The results of this study are not consistent with the hypothesis that specific virulence factors or similar H. pylori strains correlate with a specific histologic pattern or outcome even among those sharing the same environment in childhood.