| Esophageal carcinoma (EC) is one of the most common tumors of human being. China is the country with highest incidence and mortality rate of EC. Research showed that risks in different place varies in western countries alcohol intake and smoking were studied deeply. As far as know environmental carcinogen exposure is regarded as the main risk factor of EC, genetic susceptibility such as metabolic enzyme activity and the action of oncogene or tumor supper oncogene, may involve in the process. Risk factors for EC in Xi'an area had been studied by serial case control studies. Environment factor such as smoking is a constant risk factor for EC. Molecular epidemiology enables us to study more closely on the process of the carcinogenesis, the interaction of exposure of environment and the susceptibility factors. Metabolic enzymes such as CYPL4J and GSTM1 involve in the activation andlor detoxification of pro-carcinogen. CYP1A1 Ile-Val polymorphism and GSTM1 deletion or not affect the enzyme ability to activate or deactivate of procarcinogen, which can be partly explained the different EC risk of the similar environment exposure, such as heavy smoking. We suppose that EC occurs only when person with the high susceptibility background and exposure of environment risk factors. So we combined traditional epidemiology and molecular epidemiology methods to carry out a hospital based case control study. All cases and controls from Tangdu hospital during Nov.1999 to April 2000 period. Cases were all confirmed by pathologic diagnosis, and controls were randomly selected with no cancer inpatients. Cases and controls were confined to be resident of Xi'an area. There are 127 cases (male 97,female 30) and 101 controls (male 78,female 23) included. There are no significant difference in age gender distribution in cases and controls. Results showed that smoking (OR=2 04. 95%Cl 115-3 60 .),alcohol drinking (OR3 .45,95%CI 1.74-6.91), family cancer history (OR=2.82,95%CI 1.31-6.17) especially EC family history (OR=3.14, 95%CI 1.28-7.94) are the risk factors. And intakes less animal protein (OR~=3.02,95%CI 1.70-5.40), intake less fresh vegetables (OR=3.54,95%CI 1.66-7.65) are also risk factors. Logistic regression analysis showed factors as profession, smoking, alcohol intake, lack of protein and vegetable intake and the genotype of CYPIAJ entered the model; factors are all risk factors except for profession. We used CYP1AJ and GSTMI as genetic susceptibility markers, the polymorphism of CYP1A I fle- Va! and GSTMI deletion or not were analysis in 127 cases and 101 controls. Blood coagulate were collected from the biochemistry lab of the hospital. Conventional method was followed to extract DNA from the peripheral blood. Metabolic enzyme polymorphisms were detected by PCR method. The distribution of CYPLAI exon 7 polymorphism( lie/lie. Va//lIe, and Va//Va!) were significant different in cases and controls( x2=1 0.6 P=0.005),GSTMJ deletion in cases and controls were also significant different( x2=4.85 P?.028). The distribution of polymorphism of CYP1AJ and GSTM1 did not show significant relations with age, gender, profession, smoking and alcohol drinking. Environmental factors, such as smoking and alcohol drinking appear interaction with CYPIAI Va//Va! genotype and GSTMldeletion genotype. In conclusion, this molecular epidemiology researches provided...
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