[Evaluation of gene expression for cag A in strains of Helicobacter pylori colonizing gastric mucosa].

Recent studies indicate that infection with H. pylori strains expressing cytotoxic proteins such as cag A or vac A is an important risk factor for the development of chronic atrophic gastritis, gastric cancer, or MALT-type lymphoma. The aims of this study were: 1) to develop an RT-PCR assay for the analysis of cag A gene expression in H. pylori present in gastric mucosa specimens obtained during gastroendoscopy; 2) to examine with this method the correlation between the presence of cag A gene and its expression. The study was performed in 82 patients (40 females and 42 males). cag A DNA was detected in gastric mucosa in 42 patients, among them in 17 out of 35 with dyspepsia, in 14 out of 25 with peptic ulcer disease, in 2 out of 10 with gastric cancer and in 8 out of 11 with a family history of gastric cancer (Tab. 1). cag A gene expression could not be confirmed in only two cases positive for cag A DNA (both patients had a family history of gastric cancer, Fig. 1). The results of this study indicate that the RT-PCR assay is a useful tool for the molecular diagnostics of H. pylori infection. Further studies are needed to explain the role of cag A gene in the pathogenesis of peptic ulcer and gastric tumors.