| Gastric cancer (GC) is one of the most common tumors in many countries in the world, and its high fatality rate seriously imperil the health of people. Although GC is declining in frequency in the world, its incidence rate still maintain a high level in China, Japan and Latin American areas. In China, GC is the leading cause of cancer death, and its etiology is intricate. Many studies have suggested that environmental and genetic factors may play important roles. So, it is urgent to find out GC etiology and take effective prevention measures. To reach this target, a population-based molecular epidemiological study on GC was conducted in the two high-risk areas of Jintan and Huai'an county of Jiangsu Province.Part I A Study on the Relationship between theGenetic Polymorphism of Interleukin-1 β andSusceptibility to Gastric CancerIt was reported that interleukin-lB gene polymorphisms were suspected of enhancing production of interleukin-1 β which associated with an increased risk of both hypochlorhydria induced by H.polyri and gastric cancer. Thus, we used PCR-based RFLP analysis to explore the genotype frequencies of polymorphisms in the interleukin-lB (IL-1B) gene promoter region -31, -511 and +3954 loci in gastric cancer cases and cancer-free controls, and evaluate the association between polymorphisms of IL-1B genes and host susceptibility to gastric cancer.1. The distribution of genotypes of IL-1B in cases and controlsThe wild-type homozygote CC genotype frequencies of IL-1B-31 loci were 21.8% and 27.9%, respectively, in cases and controls, and the mutant-type homozygote TT genotype frequencies were 29.6% and 23.3%, respectively. The risk for GC in those with - 3ITT genotype was significantly higher than those with -3ICC genotype, with an adjusted OR of 1.75 (OR=1.75 95%CI=1.08-2.85).The wild-type homozygote TT genotype frequencies of IL-1B-511 loci were 18.2% and 24.9%, respectively, in cases and controls. Compared to TT genotype, individuals with -511CT and -51 ICC genotypes have a borderline significantly increased risk of gastric cancer (OR=1.46, 95%Cl=0.94-2.25 for -511CT and OR=1.63, 95%CI=0.98-2.73 for -51 ICC, respectively).We only found two genotypes of +3954CC and +3954CT of 1L-1B+3954 loci. The genotype frequencies of+3954CT were 5.3% and 2.6%, respectively, in cases and controls. Because of the limited sample size, we didn't find significant differences between +3954 loci polymorphisms and risk of gastric cancer( OR=1.93, 95%CI=0.77-4.85 ).2 A stratified analysis between IL-1B gene polymorphisms and risk factors on GCIn a stratified analysis, significant differences were observed in terms of the associations between IL-1B-31 and -511 loci genotypes and gastric cancer risk for male, individuals with H.polyri infection and without history of GC3. Comparison of IL-1B gene polymorphism in different racesThe genotype frequencies of IL-1B-31 were discrepant in different researches and races. The frequencies of CC genotype were 75.7% in highest, 18.3% in lowest, 27.9% in our study, which were consistent with the results from Japan and Taiwan.There also existed significant difference among races in IL-1B-511 gene polymorphisms. The frequencies of T allele were about 35% in Europeans and 45%-50% in Asian populations.The genotype frequencies of IL-1B+3954 in Asian populations had great difference with Europeans especially TT genotype, which didn't been found in our study. The frequency of CT genotype was lower than 10% and the CC genotype was the dominant one.4.The analysis of Linkage disequilibrium and HaplotypeThe results showed that there lied strong Linkage disequilibrium between IL-1B-31 and IL-1B-511, and individuals with three and four haplotype risk genotypes could increase 65% ( OR=1.65 , 95%CI=1.01-2.70 ) risk of getting gastric cancer.Part n A Study on the Relationship between the GeneticPolymorphism of Interleukin-1 Receptor Antagonistand Susceptibility to Gastric CancerInflammation is one of the most important gastric physiologi...
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