Helicobacter pylori (H. pylori) is the causative agent for upper gastrointestinal diseases. The presence of the cagA, at least with one repeat of EPIYA-C, and the vacA with s1-i1 polymorphisms are likely to be associated with increased gastric cancer risk. Aim: The aim of study was to determine the genotype of cagA and vacA and their usefulness as a predictive factor in upper gastrointestinal patients in Ilam, Iran. Cytotoxin-associated gene A (cagA) is another important factor related to H. pylori infection and development of GC [7]. Upon entrance of CagA to host cells by T4SS, several repeats of Glu-Pro-Ile-TyrAla (EPIYA) motifs have been phosphorylated by Src and Abl family kinases, whereas other CagA molecules remain un-phosphorylated, host signaling pathways disrupted and lead to abnormal proliferation of gastric epithelial cells [8, 9]. In addition, phosphorylation of the tyrosines located in the EPIYA motif of cagA induces activation of a receptor tyrosine kinase (RTK) signaling cascade [7]. It has been shown that activated RTK enhances cell proliferation and invasiveness of
the cell which might eventually result in cancer development [7]. cagA is generally accepted as a member of cag PAI (pathogenicity island) which codes a T4SS [10].