Lack of association among TNF-α gene expression,-308 polymorphism (G > A) and virulence markers of Helicobacter pylori

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.