Study Of Correlation Between IL-17 Gene Polymorphism And Gastric Cancer In Han Population

Objective: Purpose of this study was to detect the SNP site rs2275913, rs3748067, rs4711998 and rs763780 polymorphic loci of IL-17 gene in the susceptible population of gastric cancer and to explore the SNP distribution between gastric cancer patients and healthy control population with PCR-RFLP technique and DNA direct sequencing method, and results revealed the relationship between IL-17 gene polymorphism and gastric cancer.Methods: 86 gastric cancer patients were recruited from Hebei province people’s Hospital from 2013 to 2014 years with the Diagnose of Endoscopy and Pathology. Meanwhile, 374 subjects were collected as control group with matching gender and age. All the patients were excluded autoimmune and inflammatory diseases, such as systemic lupus erythematosus, diabetes, rheumatoid arthritis, inflammatory bowel disease, etc. And the patients with family history of gastric cancer were excluded, too. No any abnormalities were found in the blood analysis, urinalysis, feces routine and electrocardiogram in all subjects. Genomic DNA of each subject was extracted from 4ml EDTA-K2 anticoagulant blood specimen. Primers were designed with biological software Primer5.0 and compared with DNA sequence in the Gene Bank. PCR-RFLP was applied to amplify target gene fragments and analyze the DNA polymorphism of IL-17 gene. All the analyses were performed with the SPSS 19.0 statistical analysis package. The statistical indexes were all showed by mean ± standard deviation(mean ± SD).The frequency of genotype and allele were calculated with gene counting method. The frequencies of the alleles and the relationship of genotype of the study groups were analyzed by constructing Chi-square(χ2) and contingency tables followed by χ2 analysis. The relationship of IL-17 genotype SNP site polymorphisms and gastric cancer was analyzed by stepwise multiple linear regression analysis. P <0.05 for the difference was significant.Results:1 The difference of the gender, age and smoking history between the case group and the control group were not statistically significant(P>0.05), and positive rates of the history of drinking in the case group was higher than the control group, the difference has significant statistical(P<0.05).2 The serum levels of TNF-α, IL-6, Hs-CRP, IL-17 and CEA were higher in case group than those of control group. There were significant differences(P<0.05).3 In SNP site rs2275913 of IL-17, frequencies distribution of GG, GA, AA genotypes in case group were 0.5181, 0.3316 and 0.1503, the frequency of A allele was 0.3161, while frequencies distribution of GG, GA, AA genotypes in control group were 0.5428, 0.3289, 0.1283, the frequencies of A allele was 0.2928, The case group compared with control group, the frequencies of GA,AA genotype have no significant differences(χ2=0.116, P>0.05; χ2=0.870, P>0.05), the frequencies of A allele also has no statistically difference(χ2=0.814, P>0.05).4 In SNP site rs3748067 of IL-17, frequencies distribution of CC, CT, TT genotypes in case group were 0.7979, 0.1347 and 0.0674, the frequencies of T allele was 0.1347, while those in control group were 0.8636, 0.1203, 0.0161, the frequency of T allele was 0.0762, the frequencies of the TT genotype and T allele in case group were significantly higher than those in control group. There were significant differences(χ2=12.82, P<0.05; χ2=12.805, P<0.05).5 In SNP site rs4711998 of IL-17, Frequencies distribution of GG, GA, AA genotypes in case group were 0.3316, 0.4456 and 0.2228, the frequency of A allele was 0.4456, while those in control group were 0.3610, 0.4652, 0.1738, the frequency of A allele was 0.4064, The case group compared with control group, the frequencies of GA,AA genotype have no significant rs3748067 site polymorphism of IL-17 gene had close relationship with gastric cancer. The TT genotype of rs3748067 site significantly increased the risk of gastric cancer.3 The gene polymorphism distribution of SNP site rs763780 had significant difference between the case group and the control group. The rs763780 site polymorphism of IL-17 gene had close relationship with gastric cancer. The GG genotype of rs763780 site significantly increased the risk of gastric cancer. differences(χ2=0.065, P>0.05; χ2=2.636, P>0.05), the frequencies of A allele also has no statistically difference(χ2=1.462, P>0.05).6 In SNP site rs763780 of IL-17 gene, frequencies distributions of AA, AG, GG genotypes in case group were 0.7616, 0.1503 and 0.0881, and the frequency of T allele was 0.1632; while those in control group were 0.8342, 0.1444, 0.0214, and the frequency of G allele was 0.0936, the frequencies of the GG genotype and G allele in case group were significantly higher than those in control group, There were significant differences(χ2=16.534, P<0.05;χ2=16.399, P<0.05).7 Stepwise multiple linear regression analysis showed: Taken gastric cancer as dependent variable and genotype(GG=0,GA=1,AA=2), TNF-α, IL-6, Hs-CRP, IL-17, CEA, BMI in IL-17rs2275913 as independent variables to make regression analysis,none entered the equation(P>0.05). Considered gastric cancer as dependent variable and genotype(CC=0, CT=1, TT=2), TNF-α, IL-6, Hs-CRP, IL-17, CEA, BMI in IL-17rs3748067 as independent variables to make regression analysis, genotype entered the regression equation : y=0.531(genotype)+0.895(P<0.05). Taken gastric cancer as dependent variable and genotype(GG=0, GA=1, AA=2)、TNF-α, IL-6, Hs-CRP, IL-17, CEA, BMI in IL-17rs4711998 as independent variables to make regression analysis,none entered the equation(P>0.05).Consideredgastric cancer as dependent variable and(AA=0, AG=1, GG=2), TNF-α, IL-6, Hs-CRP, IL-17, CEA, BMI in IL-17rs763780 as independent variables to make regression analysis, genotype and IL-6 entered the regression equation:y=1.102(genotype)+0.635(IL-6)+3.135(P<0.05).Summary:1 The gene polymorphism distribution of SNP site rs2275913, rs4711998 in IL-17 gene had no significant difference between the case group and the control group, which suggested that the polymorphism of the two SNP sites might be not associated with the risk of gastric cancer.2 The gene polymorphism distribution of SNP site rs3748067 had significant difference between the case group and the control group. The...