Helicobacter pylori vacA s1m1 genotype but not cagA or babA2 increase the risk of ulcer and gastric cancer in patients from Southern Mexico

The , and genotypes of are associated with gastric pathology. The objectives were to determine the frequency of infection and distribution of the , and genotypes of in patients with gastric ulcer, chronic gastritis and gastric cancer, and to evaluate the association of virulent genotypes with diagnosis. We studied 921 patients with symptoms of dyspepsia or with presumptive diagnosis of gastric cancer. The DNA of and the , and genes was detected by PCR in total DNA from gastric biopsies. The association of and of its , and genotypes with diagnosis was determined by calculating the odds ratio (OR). Chronic gastritis was confirmed in 767 patients, gastric ulcer in 115 and cancer in 39. The prevalence of was 47.8, 49.6 and 61.5% in those groups, respectively. was more frequent in the surrounding tissue (69.2%) than in the tumor (53.8%). The genotype predominated in the three groups (45.2, 61.4 and 83.3%, respectively). was associated with cancer (OR = 2.08; 95% CI 1.05-4.13; = 0.035) but not with ulcer (OR = 1.07; 95% CI 0.71-1.61; = 0.728). The genotype was associated with ulcer and cancer (OR = 2.02; 95% CI 1.12-3.62; = 0.019 and OR = 6.58; 95% CI 2.15-20.08; = 0.001, respectively). was associated with gastric cancer, and was not associated with the diagnosis. In population from Southern Mexico, and the genotype were associated with gastric cancer and the / +/ + strains predominated in tumor and adjacent tissue.