Higher gastric mucin secretion and lower gastric acid output in first-degree relatives of gastric cancer patients

Background: Patients infected by Helicobacter pylori who have first-degree relatives with gastric cancer have an 8-fold increased risk of developing gastric cancer themselves. Mucins are high-molecular-weight glycoproteins that play a cardinal role in the protective mechanism of the gastric epithelium. Aim: To study gastric acid and mucin secretion in dyspeptic patients with and without a family history of gastric cancer and H. pylori infection. Materials and Methods: Twenty-six dyspeptic patients underwent esophago-gastro-duodenoscopy, gastric biopsies, and acid and mucin secretory tests. The sample was divided by family history of gastric cancer and H. pylori status. Results: Patients who were infected by H. pylori had a significantly higher degree of inflammation than those who were not. H. pylori-positive patients with a positive family history had a lower basal and maximal gastric acid output than infected patients with no family history and noninfected controls, and a higher basal and maximal mucin output than infected patients with no family history. MUC5AC was the major mucin species expressed in gastric juice. Conclusions: In patients with relatives with gastric cancer, H. pylori infection is associated with a more severe inflammatory reaction consisting of decreased gastric acid secretion and increased mucin secretion.