Preliminary Research On Corelationship Between Genetic Polymorphisms Of CYP2E1and Susceptibility Of Gastric Cancer In Qinghai Province

Objective: Qinghai is one of the regions of highest morbidity of gastric cancer inChina, and in where both of the morbidity and the mortality of gastric cancer arethe highest level in China. The geographic position of Qinghai is very special inChina, which lies in the northeast of Tibetan Plateau, and Qinghai is also thestarting point of Qing-Tibetan Railway where the climate is the plateaucontinental weather. All sorts of different national minorities, the distinctiveenvironment, the different living circumstances and particularly custom of thepeople in Qinghai province, which provided the ideas and clues for us to researchthe pathogenesis of gastric cancer. The incident of gastric cancer has relation withenvironmental and genetic factors. It provides clues for studying the mechanismabout gastric cancer of Qinghai region population that the unique naturalenvironment, the particular living custom of high altitude natives, diet habit, anddry, low-oxygen, low pressure living surroundings in high altitude. Carcinogensleading to gastric cancer in the circumstance, like N-nitrosamine, Aflatoxins,3,4-Benzopyrene,and so on. After the carcinogens are intaked into human body, theydevelop carcinogenic effect first by the action phraseⅠand phraseⅡmetabolicenzyme in vivo. But no all one intaking above-mentioned chemical substancesuffers from gastric cancer, and individual genetic susceptibility may be the causeleading to the above difference. so, studying the corelationship between metabolicenzyme genetic polymorphism and susceptibility of gastric cancer has significantmeanings. The way that molecular epidemiology study methods are taken to try todetect the distribution feature with CYP2E1genotype RsaI and DraI of Qinghairegion population, to analysis the association between the genetic polymorphismand susceptibility of gastric cancer or not, and then clarify the probablemechanism to provide the theory base for the early examining of high incidence gastric cancer population and the prevention and treating in Qinghai province.Methods: Polymorphisms of RsaI and DraI in CYP2E1genes were determinedby polymerase chain reaction (PCR) and polymerase chain reaction-restrictionfragment length polymorphisms (PCR-RFLP) in120patients with gastric cancerand120normal controls in Chinese Qinghai subjects．The associations betweengenetic polymorphisms and susceptibility of gastric cancer in Chinese Qinghaisubjects were analyzed．Results: The results in this study showed as follows：1. The frequency ofCYP2E1RsaI genotypes(C1／C1、 C1／C2、 C2／C2)in gastric cancergroupand control group was64.17%,32.50%,3.33%and65.83%,30.00%,4.17%respectively．No significant differences in CYP2E1RsaI genotype distributionswere found between the two groups.(X~2=0.342，P=0.843)2. The frequency ofCYP2E1RsaI allele C1and C2in gastric cancer group was81.67％and18.33％. The frequency of CYP2E1RsaI allele C1and C2in control group was82.08％and17.91％.No significant differences in CYP2E1RsaI allele C1and C2distributions were found between the two groups.(X~2=0.014，P=0.906) Thefrequency of CYP2E1RsaI allele C1and C2in Qinghai population was81.88％and18.12％.3.The frequency of CYP2E1DraI genotypes(C／C、C／D、D／D)in gastric cancer group and control group was56.67％、40.00％、3.33％and49.17％、47.50％、3.33％， respectively． No significant differences inCYP2E1DraI genotype distributions were found between the two groups.(X~2=1.40，P=0.494)4.The frequency of CYP2E1DraI allele C and D in gastriccancer group was76.67％and23.33％. The frequency of CYP2E1DraI allele Cand D in control group was72.91％and27.08％. No significant differences inCYP2E1DraI allele C and D distributions were found between the two groups.(X~2=0.895，P=0.344) The frequency of CYP2E1DraI allele C and D in Qinghaipopulation was74.79％and25.21％respectively．Conclusion: There is some significant corelationship between the pathogenesis ofgastric cancer and the Genetic Polymorphisms of CYP2E1in Qinghai province.The genotype of C1/C2、C2/C2is probably one of the protective factors for themedium or poor differential adenocarcinoma, and also, both of the genotypes of C/D and D/D are maybe one of the risk factors for the good and good-mediumdifferential adenocarcinoma gastric cancer.