title: [Genotyping of Helicobacter pylori virulence factors vacA and cagA in individuals from two regions in Colombia with opposing risk for gastric cancer].
abstract: BACKGROUND
  The overall prevalence of Helicobacter pylori infection is high in Colombia; however, in the country´s Andean region, gastric cancer rates far surpass those in coastal areas. Helicobacter pylori genotypes cagA positive and vacA s1 and m1 are associated with an increased risk of gastric cancer.
  
  
  OBJECTIVE
  To compare the distribution of H. pylori genotypes associated with virulence in two regions in Colombia with opposing risk for gastric cancer.
  
  
  METHODS
  Four hundred and one gastric antral biopsies were obtained and analyzed from 401 individuals diagnosed with non-atrophic gastritis, atrophic gastritis and intestinal metaplasia: 256 came from the high-risk area cities of Tunja and Bogotá, and 145 from the low-risk area cities of Barranquilla, Santa Marta and Cartagena. Genotyping of virulence genes vacA and cagA was performed by PCR.
  
  
  RESULTS
  No difference was observed in the frequency of H. pylori infection between the two areas (77.3% vs 77.9 %, p=non significant, ns). The presence of cagA was higher in the low-risk area (77.9% vs. 69.2 %, p=ns). The vacA s1 allele was also more prevalent in the low-risk area (61.8 % vs 72.0 %, p=ns). The vacA m1 allele was more prevalent in the high-risk area (57.2 % vs 42.8 %, p=ns). The cagA positive s1m1 combination was also more frequent in the low-risk area (48.9% vs 38.9%, p=ns).
  
  
  CONCLUSIONS
  The differences in the risk of gastric cancer in these two geographic areas cannot be explained by differences in the prevalence of infection by H. pylori or by differences in the virulence of circulating strains.
authors.affiliation: Grupo de Investigación en Cáncer y Agentes Infecciosos, Instituto Nacional de Cancerología, Bogotá, D.C, Colombia.
authors.forename: Esperanza
authors.initials: E
authors.lastname: Trujillo
authors.affiliation: Grupo de Investigación Epidemiológica del Cáncer, Instituto Nacional de Cancerología, Bogotá, D.C, Colombia.
authors.forename: Teresa
authors.initials: T
authors.lastname: Martínez
authors.affiliation: Grupo de Investigación en Cáncer y Agentes Infecciosos, Instituto Nacional de Cancerología, Bogotá, D.C, Colombia.
authors.forename: María Mercedes
authors.initials: MM
authors.lastname: Bravo
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D000942:Antigens, Bacterial / Q000235:genetics*; D001284:Atrophy; D001426:Bacterial Proteins / Q000235:genetics*; D001706:Biopsy; D003105:Colombia / Q000453:epidemiology; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D005756:Gastritis / Q000453:epidemiology / Q000382:microbiology* / Q000473:pathology; D005787:Gene Frequency; D005798:Genes, Bacterial; D005838:Genotype; D016481:Helicobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D006801:Humans; D015994:Incidence; D008297:Male; D008679:Metaplasia; D008875:Middle Aged; D012306:Risk; D013270:Stomach / Q000382:microbiology / Q000473:pathology; D013274:Stomach Neoplasms / Q000453:epidemiology* / Q000382:microbiology; D014774:Virulence / Q000235:genetics
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori