Study On The Interaction Of Environmental And Genetic Risk Factors In Gastric Cancer

OBJECTIVE: To screen environmental and genetic risk factors to gastric cancer susceptibility in Nanjing area, estimate the attributable risk and gene-environment interaction, and provide valuable datum for the precaution of gastric cancer.METHODS: A 1:1 case-control study was carried out of 244 cases (177 males and 67 females) and controls in Nanjing area, epidemiology datum about environmental exposure was gathered in person interview. PCR-RFLP and AS-PCR technology was used to determine the genotypes of CYP2E1, GSTM1, GSTT1, NAT2, ALDH2, MTHFR, XRCC1, IL-1B and VDR. Conditional-logistic regression model were presumed to screen the environmental and genetic risk facors of gastric cancer, the adjusted attributable risk(ARc) and the summary attributable risk(sAR) and gene-environment interaction were calculated to estimate the effects of environmental and genetic risk factors on gastric cancer susceptibility. Further analysis was managed to screen the environmental and genetic risk factors in males and females.RESULTS: 5 environmental risk factors were screened out: family history of tumor (OR=3.552, 95%CI=1.687～7.479), alcohol consumption (OR=1.795, 95%CI=1.097～2.937), pickled food (OR=1.461, 95%CI=1.095～1.949), irregular diet habit (OR=1.728, 95%CI= 1.286～2.322), little fruit intake(OR=1.522, 95%CI=1.191～1.945) and the sAR were 12.37%,16.52%,21.82%,24.16% and 38.47% separately, the sAR was amount to 72.29%. The genetic risk factors associated to gastric cancer susceptibility were CYP2E1 wild genotype(OR=1.548, 95%CI=1.144～2.093), NAT2M1 mutant genotype(OR=2.204, 95%CI= 1.429～3.398), NAT2 slow acetylator(OR=2.058, 95%CI =1.082～3.915), MTHFR A1298C mutant genotype (OR=1.633, 95%CI=1.085～2.456), XRCC1 194 mutant genotype(OR=1.488, 95%CI=1.077～2.056), and the interaction of different genes was found.Combined the environmental risk factors with genetic ones, ARc of the gastric cancer risk factors were family history of tumor(11.31%), pickled food(23.85%), irregular diet habit(23.70%), little fruit intake(41.15%), CYP2E1 wild genotype(49.23%), NAT2M1 mutant genotype(18.74%), sAR was amount to 88.17%. Interaction of CYP2E1, NAT2 M1 and pickled food, irregular diet habit and little fruit intake was observed. Risk of gastric cancer increased of people who both carry CYP2E1 wild genotype and often eat pickled food, the interaction of CYP2E1 and eat pickled food showed a low exposure-gene effect(LEG); Risk of gastric cancer increased of people who both carry CYP2E1 wild genotype and had irregular diet habit, the interaction of CYP2E1 and irregular diet habit showed a high exposure-gene effect (HEG); Risk of gastric cancer increased of people who both carry...