Helicobacter pylori: seroprevalence and colorectal cancer.

BACKGROUND: Previous studies have published controversial results regarding a connection between Helicobacter pylori infection and colorectal cancer. One possible mechanism is increased gastrin secretion in subjects infected with H. pylori, insofar as gastrin is known to be a trophic factor for the colonic mucosa. OBJECTIVES: To investigate a possible role of gastrin secretion in H. pylori infection associated with colorectal cancer, and determine whether H. pylori infection is a factor in this disease. METHODS: The serum gastrin levels and the presence of H. pylori IgG antibodies were measured in 51 colorectal cancer patients and 51 control subjects. The cancer patients were also tested for carcinoembryonic antigen and CA 19-9. RESULTS: H. pylori IgG antibodies were found in the serum of 41 (80.4%) of the cancer patients compared to 32 (62.7%) of the control subjects (P = 0.05). A significant correlation was found between CA 19-9 (r = 0.3432, n = 49, P = 0.01) and seropositive H. pylori IgG antibodies in the serum of the cancer patients (odds ratio 2.43, and 95% confidence limit 0.99-5.95), but none between CEA and H. pylori IgG antibodies nor between the serum gastrin level and the presence of colorectal cancer. CONCLUSIONS: The results of this study indicate a significant association between seropositive H. pylori IgG antibodies and elevated CA 19-9 in colorectal cancer patients, but no correlation between the serum gastrin level and the presence of this cancer. H. pylori seropositivity is more prevalent in patients with colorectal cancer.