Risk assessment in relatives of gastric cancer patients: hyperproliferation, genetics, and Helicobacter pylori infection.

Approximately 10% of cases of gastric cancer present with some kind of familial aggregation, but only 1-3% of gastric carcinomas arise as a result of clearly defined genetic syndromes that require genetic counselling and aggressive preventative measures. In the remaining families, no specific abnormalities, either genetic, biochemical or histological, responsible for the increased risk have been identified. However, several lines of evidence suggest that the increased cancer risk in first-degree relatives of gastric cancer probands is mostly dependent on Helicobacter pylori infection clustering.