Abstract
BackgroundThe vacA, cagA and babA2 genotypes of Helicobacter pylori are associated with gastric pathology. The objectives were to determine the frequency of infection and distribution of the vacA, cagA and babA2 genotypes of H. pylori in patients with gastric ulcer, chronic gastritis and gastric cancer, and to evaluate the association of virulent genotypes with diagnosis.MethodsWe studied 921 patients with symptoms of dyspepsia or with presumptive diagnosis of gastric cancer. The DNA of H. pylori and the vacA, cagA and babA2 genes was detected by PCR in total DNA from gastric biopsies. The association of H. pylori and of its cagA, vacA and babA2 genotypes with diagnosis was determined by calculating the odds ratio (OR).ResultsChronic gastritis was confirmed in 767 patients, gastric ulcer in 115 and cancer in 39. The prevalence of H. pylori was 47.8, 49.6 and 61.5% in those groups, respectively. H. pylori was more frequent in the surrounding tissue (69.2%) than in the tumor (53.8%). The vacA s1m1 genotype predominated in the three groups (45.2, 61.4 and 83.3%, respectively). H. pylori was associated with cancer (ORadjusted = 2.08; 95% CI 1.05–4.13; p = 0.035) but not with ulcer (ORadjusted = 1.07; 95% CI 0.71–1.61; p = 0.728). The s1m1 genotype was associated with ulcer and cancer (ORadjusted = 2.02; 95% CI 1.12–3.62; p = 0.019 and ORadjusted = 6.58; 95% CI 2.15–20.08; p = 0.001, respectively). babA2 was associated with gastric cancer, and cagA was not associated with the diagnosis.ConclusionsIn population from Southern Mexico, H. pylori and the s1m1 genotype were associated with gastric cancer and the s1m1/cagA+/babA2+ strains predominated in tumor and adjacent tissue.
Highlights
The vacA, cagA and babA2 genotypes of Helicobacter pylori are associated with gastric pathology
The prevalence of H. pylori was 47.8, 49.6 and 61.5% in chronic gastritis, gastric ulcer and cancer patients, respectively and the infection with this bacterium is associated with gastric cancer
The s1 and m1 alleles of vacA are predominant in this population, and the s1m1 genotype is associated with gastric ulcer and cancer
Summary
The vacA, cagA and babA2 genotypes of Helicobacter pylori are associated with gastric pathology. The objectives were to determine the frequency of infection and distribution of the vacA, cagA and babA2 genotypes of H. pylori in patients with gastric ulcer, chronic gastritis and gastric cancer, and to evaluate the association of virulent genotypes with diagnosis. Infection with babA2-positive H. pylori has been associated with gastric ulcer, duodenal ulcer and gastric adenocarcinoma and is related to increased risk of severe disease when it coexists with the cagA gene and the vacA s1 allele. The association of BabA2 with severe gastric disease is controversial, but it is known that the interaction between BabA2 and L eb activates the production of pro-inflammatory cytokines (CCL5, IL-8) and other molecules related to precancerous lesions (CDX2, MUC2) [1, 2, 15,16,17,18]. The frequency of babA2-positive H. pylori ranges from 21.7 to 82.3% in Latin American countries [10, 19, 20]
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