Objectives: This study aimed to demonstrate the tyrosine phosphorylation motif (TPM) and 3’ regionstructure of the Helicobacter pylori CagA gene as well as its SHP-2 binding activity in AGS cells and relation togastric carcinogenesis. Methods: Sixteen clinical isolate H. pylori strains from eight duodenal ulcer and eightgastric adenocarcinoma patients were studied for CagA repeat sequence EPIYA motifs, C-terminal structure,and western blot analysis of CagA protein expression, translocation, and SHP-2 binding in AGS cells. Results:Except for strain 547, all strains from the gastric adenocarcinoma patients were positive for CagA by PCRand had three EPIYA copy motifs. Western blotting showed that all strains were positive for CagA proteinexpression (100%), CagA protein translocation (100%), and SHP-2 binding (100%). CagA protein expressionwas significantly higher in the gastric adenocarcinoma patients than in the duodenal ulcer patients (P=0.0023).CagA protein translocation and SHP-2 binding in the gastric adenocarcinoma patients were higher than those inthe duodenal ulcer patients, but no significant differences were found between the two groups (P=0.59, P=0.21,respectively). Conclusions: The TPMs and 3’ region structures of the H. pylori CagA gene in the duodenal ulcerand gastric adenocarcinoma patients have no significant differences.
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