title: Lack of association among TNF-α gene expression, -308 polymorphism (G > A) and virulence markers of Helicobacter pylori.
abstract: BACKGROUND
  Tumor necrosis factor plays a critical role in the pathogenesis of gastric diseases such as gastric cancer, and an abnormal inflammatory response has frequently been observed in dyspeptic patients. Helicobacter pylori infection can induce a gastric mucosal inflammatory response that may be influenced by -308 (G > A) polymorphisms and gene expression of the TNF-α gene.
  
  
  METHODS
  One hundred and thirty-four gastric biopsy samples were collected from patients of both genders (61♂ and 73♀, mean age 40.3 ± 24.2 years) with gastric symptoms. The -308 (G > A) polymorphism of TNF-α was characterized using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The expression level was measured using real-time PCR, and relative quantification (RQ) was calculated using the comparative CT method (2(-ΔΔCT)).
  
  
  RESULTS
  The analysis revealed an increase in TNF-α gene expression in patients with gastritis; on the other hand, no statistical differences were observed in patients with gastric cancer. In addition, no association was found among -308 polymorphism genotypes, virulence markers, or TNF-α gene expression.
  
  
  CONCLUSIONS
  Helicobacter pylori induces a large increase in TNF-α expression in patients with gastritis, regardless of tissue inflammation, but after the tissue becomes neoplastic, the presence of bacteria did not influence expression. These results suggest that the TNF-α pathway may play an important role in the progression from gastritis to gastric cancer.
authors.affiliation: Universidade Sagrado Coração, Rua Irmã Arminda 10-50, Jardim Brasil, CEP 17011-160 Bauru, SP Brazil.
authors.forename: Luanna Munhoz
authors.initials: LM
authors.lastname: Zabaglia
authors.affiliation: Universidade Sagrado Coração, Rua Irmã Arminda 10-50, Jardim Brasil, CEP 17011-160 Bauru, SP Brazil.
authors.forename: Mariane Avante
authors.initials: MA
authors.lastname: Ferraz
authors.affiliation: Universidade Sagrado Coração, Rua Irmã Arminda 10-50, Jardim Brasil, CEP 17011-160 Bauru, SP Brazil.
authors.forename: Weendelly Nayara
authors.initials: WN
authors.lastname: Pereira
authors.affiliation: Universidade Sagrado Coração, Rua Irmã Arminda 10-50, Jardim Brasil, CEP 17011-160 Bauru, SP Brazil.
authors.forename: Wilson Aparecido
authors.initials: WA
authors.lastname: Orcini
authors.affiliation: Faculdade de Medicina de Marília, Rua Lourival Freire 240, 17519-050 Marília, SP Brazil.
authors.forename: Roger Willian
authors.initials: RW
authors.lastname: de Labio
authors.affiliation: Faculdade de Medicina de Marília, Rua Lourival Freire 240, 17519-050 Marília, SP Brazil.
authors.forename: Agostinho Caleman
authors.initials: AC
authors.lastname: Neto
authors.affiliation: Universidade Federal de São Paulo, Rua Sena Madureira, 1500, 04021-001 São Paulo, SP Brazil.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Wisnieski
authors.affiliation: Universidade Sagrado Coração, Rua Irmã Arminda 10-50, Jardim Brasil, CEP 17011-160 Bauru, SP Brazil.
authors.forename: Juliana Garcia
authors.initials: JG
authors.lastname: de Oliveira
authors.affiliation: Universidade Federal de São Paulo, Rua Sena Madureira, 1500, 04021-001 São Paulo, SP Brazil.
authors.forename: Marilia
authors.initials: M
authors.lastname: de Arruda Cardoso Smith
authors.affiliation: Universidade Sagrado Coração, Rua Irmã Arminda 10-50, Jardim Brasil, CEP 17011-160 Bauru, SP Brazil ; Faculdade de Medicina de Marília, Rua Lourival Freire 240, 17519-050 Marília, SP Brazil.
authors.forename: Spencer Luiz Marques
authors.initials: SL
authors.lastname: Payão
authors.affiliation: Universidade Sagrado Coração, Rua Irmã Arminda 10-50, Jardim Brasil, CEP 17011-160 Bauru, SP Brazil.
authors.forename: Lucas Trevizani
authors.initials: LT
authors.lastname: Rasmussen
keywords: Gastric cancer; Gene expression; H. pylori; TNF-α; cagA