Examination of Geographical, Clinical and Intrahost Variations in the 3' Repeat Region of CagA Gene in Helicobacter pylori

The size variation of the cytoxin-associated protein (cagA), which is dependent on the 3' repeat region (3'RR) of the cagA gene, is known to play a crucial role in the pathogenesis of Helicobacter pylori infection. The present study evaluated the relationship between the 3'RR variation and the geographic distribution, clinical manifestations, and locations of colonization in the stomach. We evaluated the 3'RR of H. pylori isolates from 78 patients with gastric cancer, peptic ulcer, and non-ulcer dyspepsia from Japan, Hong Kong, India, and the United States and assessed the variations of 3'RR according to the geographical and clinical characteristics. Sixty eight (87.2%) patients had the same 650 bp band without geographical differences. The frequency of polymorphisms in the 3'RR did not differ when compared to the clinical manifestations (P=0.868). The length of 3'RR did not differ by location of colonization. In conclusion, the 3'RR variation of cagA gene is not associated with the geographical and clinical characteristics of the patients studied.