H. pylori Infection and Virulence Factors cagA and vacA (s and m Regions) in Gastric Adenocarcinoma from Pará State, Brazil

Abstract

H. pylori shows a great variability in genes associated with virulence, which may influence properties related to gastric adenocarcinoma initiation and progression. Among them, cagA and vacA show a strong positive association with the disease. Therefore, a cross-sectional study was carried out with 281 samples of gastric adenocarcinoma, collected at a cancer reference center in the Brazilian Amazon. Detection of H. pylori was proceeded by PCR of the ureA and 16S genes. Positive samples were subjected to the cagA detection and vacA typing. The bacteria were observed in 32.03% of the samples. Positivity for H. pylori was associated with advanced age (p = 0.0093) and metastases (p = 0.0073). Among the positive cases, 80% (72/90) had the cagA gene. For the “s” position of the vacA gene, 98.8% (83/84) of the bacteria had genotype s1 and 1.2% (1/84) were genotyped as s2. For the “m” position, the results were: 63.6% (56/88) with m1 genotype, 2.3% (2/88) genotyped as m2 and 34.1% (30/88) m1/m2. Virulence factors did not impact an increase in the association with age or metastases. In conclusion, H. pylori infection is associated with malignant phenotype cases of gastric adenocarcinoma, involving metastases. The virulence factors related to the cagA and vacA genes showed a high prevalence in the Brazilian Amazon.

Differential Expression of α-Enolase in Clinical Gastric Tissues and Cultured Normal/Cancer Cells in Response to Helicobacter pylori Infection and cagA Transfection

“…The H. pylori cytotoxin-associated gene A ( cagA ) is a pathogenic virulence factor, positive in 60~70% of H. pylori strains [ 6 , 7 ]. The patients infected with H. pylori cagA + strains are at higher risk for gastric cancer than the cagA - controls [ 8 ].…”