The relationship between Helicobacter pylori genes cagE and virB11 and gastric cancer

Summary 

Background

The association between Helicobacter pylori gene diversity and gastric cancer has been poorly reported, although it is one of the important ways to explain the gastric pathogenesis. The aim of this study was to investigate the frequency of cagE and virB11 genes in H. pylori isolated from patients with gastric cancer and to analyze the histology profiles.

Materials and methods

The presence of H. pylori and subtypes (cagE and virB11) was detected by PCR from the genomic DNA of 101 patients who had been diagnosed with gastric cancer. The cases were grouped according to the presence/absence of the genes studied and were analyzed in relation to histopathological parameters.

Results

H. pylori infection was detected in 94 out of 101 (93.1%) gastric carcinomas. The cases were categorized into the following groups: cagE+/virB11+, cagE+/virB11−, cagE−/virB11+, and cagE−/virB11−. Frequencies were: 50% (47/94) cagE+/virB11+, 3.2% (3/94) cagE+/virB11−, 10.6% (10/94) cagE−/virB11+, and 36.2% (34/94) cagE−/virB11−. Tumors in the gastric antrum were predominant. An exception was the cagE−/virB11− group, in which tumors had a tendency to be located in the gastric cardia; the majority of the cardia tumors (56% (14/25)) were in this group. Intestinal histology type was the most frequent, but the cagE+/virB11− group only had diffuse tumors. H. pylori cagE+/virB11+ occurred most frequently (except at stage III), and was present at all gastric cancer stages.

Conclusions

This study is the first to include a relevant number of gastric cancer cases with H. pylori infection, reporting the frequency and relationship of cagE and virB11 genes and the genesis of this tumor. The presence of these cag pathogenicity island genes shows that they are important factors for the pathogenesis and malignancy of gastric cancer related to H. pylori.

Keywords: Gastric cancer, Helicobacter pylori, Genotype