Helicobacter pylori is a genetically diverse bacterial pathogen and its CagA gene is a major virulence
factor that plays an important role in gastroduodenal pathologies. The biological function of cagA depends on tyrosine phosphorylation within the EPIYA (Glutamate-Proline-Isoleucine-TyrosineAlanine) motifs at the C terminal region of the protein. This region may undergo polymorphism to give different types of EPIYA motifs. EPIYA motif diversity may provide a useful tool for prediction of H. pylori pathogenic activity and accurate determination of number and type of cagA EPIYA motifs could identify the virulent H. pylori.