TNF Gene Polymorphisms and Helicobacter Pylori Infection in Gastric Carcinogenesis in Chinese Population

BACKGROUND AND AIMS Helicobacter pylori (H. pylori) is a major cause of chronic gastritis and peptic ulcer disease, and a definite carcinogen for gastric adenocarcinoma. However, the underlying pathogenic mechanisms have not been fully understood although the interactions between environmental, bacterial, and multiple genetic components are likely to be involved. Tumor necrosis factor (TNF) is a key cytokine involved in H. pylori-induced gastric inflammation. The present study aimed to determine the di-allelic polymorphisms of TNF gene and their association with H. pylori infection and gastroduodenal diseases in Chinese population of Han nationality. METHODS Two hundred and ten patients with gastroduodenal diseases (73 chronic gastritis, 78 duodenal ulcer, and 59 noncardia gastric cancer) and 264 healthy controls were genotyped by the PCR-RFLP method for TNF-α 308, lymphotoxin-α (LT-α) NcoI, and AspHI gene polymorphisms. H. pylori infection status was determined by a validated serological test. RESULTS H. pylori infection was detected in 90.5% of 210 patients and 62.1% of 264 healthy controls (p < 0.0001; odds ratio [OR]= 5.793; 95%CI: 3.431–9.780). Frequency of LT-αNcoI A/G genotype in patients with noncardia gastric cancer with H. pylori infection was significantly higher than that in H. pylori-positive healthy controls (64.0% vs 46.0%; p = 0.0297; OR = 2.026; 95%CI: 1.080–3.803). There were no other associations between TNF-α 308, LT-αNcoI, and AspHI gene polymorphisms and H. pylori infection in gastroduodenal diseases. CONCLUSIONS LT-αNcoI A/G heterozygous genotype was associated with H. pylori infection in patients with noncardia gastric cancer in Chinese Han population.