Resumo

SILVA, M. R. et al. Identificação dos polimorfismos dos genes IL1B, IL1RN e TNFA na gastrite crónica associada à infecção por Helicobacter pylori e no carcinoma gástrico. J Port Gastrenterol. [online]. 2008, vol.15, n.1, pp.8-14. ISSN 0872-8178.

In chronic gastritis the alleles IL1B -511T, IL1RN +2018C and the haplotype TNFA -308A/-238A are associated with high levels of the respective cytokine production. The referred polymorphisms may also induce a high production of pro-inflammatory cytokines leading to a constant and severe inflammatory response and subsequently, gastric mucosa atrophy, hypochloridria and finally gastric carcinoma as a consequence of genetic alterations in epithelial cells after metaplastic and dysplastic phenomena. The presence of those polymorphisms representing the proinflammatory cytokines IL-1ß, IL-1RN and TNF-α were analysed in cases of chronic gastritis and gastric carcinoma. The polymorphisms IL1B -511C>T, IL1RN +2018T>C and TNFA -308G>A and -208G>A were analysed by ARMSPCR in 47 biopsies: 36 cases of gastric carcinoma, 11 cases of chronic gastritis associated with Helicobacter pylori were  studied; 39 blood samples of healthy individuals were also analysed with the Cytokine Box Typing Kit (Genebox R&D, Coimbra, Portugal). An association between the IL-1RN +2018 CC genotype and gastric carcinoma was observed (p=0.0002), while the genotype IL-1RN +2018 TT (p=0.01) was associated with disease absence. The genotypes IL-1RN +2018 CC (p=0.01), TNFA -308 AA (p=0.05) and TNFA -238 AA (p=0.0001) were demonstrated in cases of chronic gastritis and the TNFA - 308 GG and TNFA -238 GG genotypes, low producers, were associated with gastritis resistance. In this study TNFA and IL1RN polymorphisms were associated with chronic gastritis due to Helicobacter pylori infection and were also present in patients with gastric carcinoma. Therefore, if these results are confirmed those polymorphisms may be used as a biological marker of individual susceptibility in the development of gastric carcinoma in chronic gastritis.

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