Interleukin-6 polymorphism and Helicobacter pylori infection in Brazilian adult patients with chronic gastritis.

Helicobacter pylori is recognised as the most common cause of chronic active gastritis and this bacterium is also an important pathogenic factor in peptic ulcer disease. The biological factors that influence clinical outcome in H. pylori infection have been extensively studied. In addition to immunological factors in the host, bacterial virulence determinants in H. pylori strains are likely to play a crucial role in gastric cancer development. Singlenucleotide polymorphisms at the 5' flanking region of the interleukin (IL)-6 gene promoter (G or C at -174 base) have been identified and individuals with the G allele at position -174 have been shown to produce higher levels of IL-6 than those with the C/C genotype. The mucosal levels of IL-6 were reported to be increased in H. pylori-associated gastritis. The present study was conducted to examine any relationship between inflammatory cytokine polymorphisms and the inflammatory process in mucosa infected by H. pylori. In our study we did not find any association between the C and G alleles in adult patients with chronic gastritis and inflammatory process in gastric mucosa.

Polymorphisms of the TP53 codon 72 and WRN codon 1367 in individuals from Northern Brazil with gastric adenocarcinoma.

Gastric cancer is the second most frequent type of neoplasia and also the second most common cause of death in the world. TP53 codon 72, which produces variant proteins with an arginine (Arg) or proline (Pro), has been reported to be associated with cancers of the lung, oesophagus, stomach and cervix. Werner's syndrome (WS) is a premature ageing disease caused by a mutation in the WRN gene. The WRN protein acts as a DNA helicase and as an exonuclease. WRN codon 1367 produces variant proteins with an Arg or cysteine (Cys). This polymorphism has been studied, in order to understand the clinical impact of the molecular variants in WS and in age-related disorders. In the present study, the TP53 codon 72 and the WRN codon 1367 polymorphisms were investigated in 54 gastric adenocarcinoma patients (31 diffuse-type and 25 intestinal-type) and 54 controls. DNA samples were extracted, and PCR-RFLP was utilised for genotyping TP53 codon 72 and WRN codon 1367. The allele frequencies of the TP53 polymorphism were: Arg=0.74 and Pro=0.26. The allele frequencies of the WRN polymorphism were: Cys=0.73 and Arg=0.27. The crude genotypic frequencies in gastric cancer patients were similar to those of the controls, but in the WRN codon 1367 polymorphisms the mean age tended to be higher in the Arg/Arg genotypes. There also was an association, although not statistically significant, between the presence of Helicobacter pylori and the genotypes Cys/Cys and Cys/Arg and a higher percentage of cardia cancer among the Arg/Arg genotypes, and of non-cardia cancer among genotypes Cys/Cys and Cys/Arg. These findings may be a reflection of differences in the interaction between WRN codon 1367 polymorphisms and local factors in the stomach. To our knowledge, this is the first study to examine a genetic polymorphism of the WRN gene in cancer. The precise mechanisms of action of the TP53 and WRN polymorphisms involved in the aetiopathogeny of this disease need further investigation.

Helicobacter pylori and cagA and vacA gene status in children from Brazil with chronic gastritis.

Helicobacter pylori has been shown to be strongly associated with chronic gastritis, gastric and duodenal ulceration, and is a risk factor for gastric carcinoma. Histology, urease, culture, and polymerase chain reaction have been employed as for H. pylori diagnostic methods, pre and post treatment or during follow-up of dyspeptic adult individuals referred for endoscopy. In order to obtain a more-sensitive and specific method for H. pylori detection, we evaluated gastric body and antrum biopsies of 134 consecutive Brazilian consecutive dyspeptic children aged 1-16 years by rapid urease test, histology and polymerase chain reaction using two pairs of oligonucleotides. Our results indicated that polymerase chain reaction with Southern blotting and hybridization with specific chemiluminescent probes increased the number of positive H. pylori patients by 35%. The genotyping of H. pylori strains directly from gastric biopsy using the same nucleic acid methodology revealed that there is no association of chronic gastritis in our infant patients with vacA s1 and the presence of the cagA gene. These data suggest an initial infection of children with normal mucosa and probably others factors than vacA s1 genotype or the presence of the cagA gene are associated with the onset of gastric disease. Altogether, our results reinforce the need for using more sensitive diagnostic methods in order to understand the role of H. pylori in the genesis of gastric disease in children and its progression in adults.