Genetic Heterogeneity of Helicobacter pylori Putative Virulence Genes and Association with Clinical Outcomes, Recent Studies and Future Perspectives

Helicobacter pylori (H. pylori) plays an important role in the development of peptic and duodenal ulcerations as well as gastric cancer. Several studies have shown a strong association between specific genotypes of H. pylori and gastrointestinal tract diseases. The vacA and cagA genes, which are the putative virulence factors of the bacterium, are important determinants of H. pylori-related diseases. Polymorphisms of the signal peptide (s), middle (m), and intermediate (i) regions of the vacA gene, presence of the cagA, and genetic heterogeneity of the C-terminal motifs of CagA might result in varying clinical outcomes in H. pylori-infected patients. In this review article, the intracellular activities of VacA and CagA proteins, the genetic diversity of the coding sequences of these proteins, their association with clinical outcomes with regard to the status of H. pylori infection in Iran, and future perspectives are discussed.