Infecção por Helicobacter pylori e câncer gástrico: freqüência de cepas patogênicas cagA e vacA em pacientes com câncer gástrico

Abstract

Background: The rates of Helicobacter pylori infection are very high worldwide, but only a minority of infected patients develop gastric carcinoma. This might be related, among several factors, to the colonization of the human stomach by pathogenic Helicobacter pylori strains. Objective: To investigate the distribution of cagA and vacA genotypes of Helicobacter pylori in paraffin-embedded gastric samples from patients with gastric cancer. Material and methods: Paraffin-embedded samples from 42 patients with gastric cancer were histologically examined and evaluated by PCR for H. pylori cagA and vacA (s and m regions) genotypes. Results: Histological analysis allowed direct visualization of H. pylori in 85.7% of cases and PCR for urease C gene detected H. pylori in 95% of cases. The presence of cagA gene was detected in 23 (54.7%) patients with gastric cancer. The s1 allele from vacA gene was found in samples from 24 (57.1%) patients and the m1 allele in 26 (61.9 %). The s1m1 genotype was detected in 24 (57.1%) patients with gastric cancer. The s2 allele was found in samples from four patients (9.5%) and the m2 allele in three (7.1%) patients. The distribution of H. pylori genotypes was similar in both intestinal and diffuse types of gastric carcinoma. Conclusion: Our results confirm the relevance of the pathogenic cagA and vacA H. pylori genotypes for significant organic lesions, such as gastric cancer, suggesting a possible role for H. pylori in the pathogenesis of gastric carcinoma. Helicobacter pylori Gastric cancer cagA vacA J Bras Patol Med Lab • v. 42 • n. 1 • p. 25-30 • fevereiro 2006 ARTIgO ORIgINAL ORIgInal papER Primeira submissão em 29/09/05 Última submissão em 21/12/05 Aceito para publicação em 11/01/06

Occurrence of Helicobacter pyloriand Epstein-Barr virus infection in endoscopic and gastric cancer patients from Northern Brazil

“…The prevalence of HP in gastric tumors varies with the country being analyzed [ 39 ]. In Brazil, a previous study detected this bacteria in 85.7% of gastric tumor samples [ 40 ], which is similar to the frequency observed in our study (88%). In addition, we observed that the frequency of HP was 1.5-times greater in GC samples than in juvenile gastritis samples, and almost ninety times higher than in normal gastric mucosa, highlighting a strong association between HP and the process of gastric carcinogenesis.…”

Evaluation of the Pattern of EPIYA Motifs in the Helicobacter pylori cagA Gene of Patients with Gastritis and Gastric Adenocarcinoma from the Brazilian Amazon Region

“…CagA has been associated with increased gastric inflammation characterized by high-grade leukocyte infiltration, which is a long-term risk factor for carcinogenesis since the intense oxidative process triggered by the disintegration of cells in the gastric mucosa releases potentially mutagenic substances [ 26 , 27 ]. Some studies suggest that the number of EPIYA-C repeats is not associated with proinflammatory cytokine production but rather increases the binding to SHP-2, with consequent morphological changes in the cell that induce mucosal damage [ 25 , 28 ].…”

Molecular Epidemiology of Helicobacter pylori in Brazilian Patients with Early Gastric Cancer and a Review to Understand the Prognosis of the Disease

“…After DNA extraction, PCR for ureaseC [92], vacA (s and m) [93,94,95], cagA [96], cagT [97] and dupA (jhp0917 and jhp0918) [49] genes were performed. Primers pairs for all the genes as well as the length of the fragments are described in Table 1.…”