Association between diversity in the Src homology 2 domain--containing tyrosine phosphatase binding site of Helicobacter pylori CagA protein and gastric atrophy and cancer

J Infect Dis. 2004 Mar 1;189(5):820-7. doi: 10.1086/381782. Epub 2004 Feb 2.


We investigated the relationship between the diversity of Helicobacter pylori CagA protein and clinical outcome. The cagA gene was sequenced in 115 clinical isolates. The binding affinity of CagA to Src homology 2 domain-containing tyrosine phosphatase (SHP-2) was examined by in vitro infection. Two major CagA subtypes were observed--the East Asian and the Western type. The grades of inflammation, activity of gastritis, and atrophy were significantly higher in patients with gastritis infected with the East Asian CagA-positive strain than in patients with gastritis infected with cagA-negative or Western CagA-positive strains. All strains isolated from patients with gastric cancer were East Asian CagA positive. East Asian CagA exhibited stronger SHP-2-binding activity than did Western CagA. These findings suggest that infection with East Asian CagA-positive H. pylori is associated with atrophic gastritis and gastric cancer and that persistent active inflammation induced by the East Asian CagA-positive strain may play a role in the pathogenesis of disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antigens, Bacterial / metabolism*
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Binding Sites
  • Conserved Sequence
  • DNA Primers
  • Gastric Mucosa / pathology*
  • Gastritis / microbiology
  • Gastritis / pathology
  • Genetic Variation
  • Helicobacter pylori / genetics*
  • Helicobacter pylori / isolation & purification
  • Humans
  • Molecular Sequence Data
  • Protein Tyrosine Phosphatases / metabolism*
  • Sequence Alignment
  • Stomach / pathology*
  • Stomach Neoplasms / microbiology
  • Stomach Neoplasms / pathology*
  • src Homology Domains


  • Antigens, Bacterial
  • Bacterial Proteins
  • DNA Primers
  • cagA protein, Helicobacter pylori
  • Protein Tyrosine Phosphatases