| Objective:Epidemiological investigation was performed to study the co-effects of NQO1, XRCC1 genetic polymorphism, environmental exposure, and their interactions on the gastric cancer at Chuzhou region in Anhui province of PRC. Present research provides possible etiological concern on gastric cancer and promote further study interest.Methods:Individual epidemiological protocol was consisted with case-control study under the 1:1 subjects matched in local hospitals. The cases with the gastric cancer have been validated through histopathology .We studied 112 cases and 112 controls matched by gender, age, nationality and inhabited zone .Questionnaire were used to gathered individual information and the major environmental exposure data .Serum was obtained from 4-5 ml vein blood, following a simple salting out protocol to extract genomic DNA .Using the PCR-RFLP assay, we identified the genotype of NQO1 and XRCC1. Odds ratio (OR) which included the interaction risk factors between the gene and environmental exposure were determined using conditional logistic regression. Estimate of 95% confidence intervals (95%CI) was made. All analysis was performed with the SPSS Version 11.0(CDC, USA).Results1. After the simple and multi-variable statistical analysis ,we found some major risk factors from the environmental exposure; a lager increase in risk for daily smoking with the gastric cancer(p=0.001,OR=4.170,OR95%CI=1.514-11.491); baked food intake showing strong association with gastric cancer(p=0.001,OR=11.379,OR 95%CI=1.668-77.672); and a significant positive association was indicated between the pesticide utilization every year in local zone with the cancer(p=0.001,OR=9.494,OR 95%CI=1.289-69.920). However,association was showed between exposure and the cancer for the fresh vegetables intake(p=0.000.OR=0.094,OR95%CI=0.022-0.405), suggesting the vegetables was the protective factor for the gastric cancer.2. The distribution of genotype was significantly different in cases versus controls. The genotype frequency of NQO1 CC, CT , and TT was 42.0%,25.0%,and 33.0% in gastric cancer group respectively ,but which was 50.9%,31.3%,and 17.8% in controls respectively. Large increases in susceptibility found among whose genotype was NQO1 TT(p=0.02,OR=2.261,OR95T%CI=1.136-4.500). The different genotype of XRCC1, including AA, AG, and GG, showed no association with gastric caner when the frequency was calculated statistically.3. Interactions between genes and related exposure factors showed different effects on gastric caner. Significant positive-interaction was observed between NQO1 TT genotype and alcohol drinking (γ>1, OR=3.142, 95%=1.068~9.241), souse intake (γ>1, OR=10.191, 95%=1.778~58.398) which appeared to act in a super-multiplicative model. But the interaction of NQO1 TT genotype and mildewed rice intake (γ<1, OR=4.302, 95%=1.126~16.427) was significantly negative. Risk of the gastric cancer increased with the decreasing of fruit intake, fresh vegetables consumption, tea drinking. There was also obvious relationship between XRCC1 GG genotype and mildewed rice intake (γ>1, OR=4.800, 95%=1.329~17.333), baked food intake (γ>1, OR=6.000, 95%=1.082~33.274) showed significant positive-interaction and a sub- multiplicative model. ConclusionThe present study indicated that individual smoking, alcohol drinking, baked food intake increased the risk of gastric cancer, but more fresh vegetables consumption regulated down the incidence of gastric caner. After the genetic polymorphism investigation, the susceptibility to gastric cancer was regulated up by NQO1 TT genotype .Co-effects on gastric cancer were also found between the NQO1, XRCC1 and different environmental exposures. In general, incidence of the gastric cancer in Chuzhou could be effectively deceased when individuals taking the well-performed behaviors and valid dietary pattern. In addition, NQO1 TT genotype could be suggested as a index in early gastric cancer diagnosis. |
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