Helicobacter pylori cagE, cagG, and cagM can be a prognostic marker for intestinal and diffuse gastric cancer.

ABSTRACT

It is known that Helicobacter pylori is the main cause of peptic ulceration and gastric cancer. However, there is a lack of information on whether H. pylori strains may differ in gastric cancer histological subtypes. This study aimed to investigate different H. pylori strains considering six cag Pathogenicity Island - cagPAI genes (cagA, cagE, cagG, cagM, cagT, and virb11), and vacuolating cytotoxin - vacA alleles, and their relation to gastric cancer histologic subtypes. For this purpose, tumor samples from 285 patients with gastric carcinoma were used. H. pylori infection and genotypes were determined by polymerase chain reaction (PCR). H. pylori was detected in 93.9% of gastric tumors. For comparative analyzes between histopathological subtypes considering H. pylori cagPAI genes the strains were grouped according to the vacA s1/s2 alleles. In the vacAs1 group, the strains cagA(-)cagE(+), cagA(+)cagE(+)cagG(+), cagA(+)cagM(+), or only cagE(+) strains were more frequent in the intestinal subtype (P = .009; P = .024; P = .046, respectively). In contrast, cagM(+)cagG(+)cagA(-) and cagE(-) were associated with diffuse tumors (P = .036), highlighting the presence of cagE in the development of intestinal tumors, and the presence of cagG and absence of cagE in diffuse tumors. Furthermore, WEKA software and Decision Tree (CART) analyses confirmed these findings, in which cagE presence was associated with intestinal tumors, and cagE absence and cagG(+) with diffuse tumors. In conclusion our results showed that vacAs1 (cagG + cagM) strains, mainly cagG positive with cagE absence, were relevant in the studied population for the diffuse outcome, while the presence of cagE was relevant for the intestinal outcome. These findings suggest the relevance of these H. pylori genes as potential markers for gastric cancer histological outcomes.