ABSTRACT
<p><b>OBJECTIVE</b>To study the association between genetic polymorphisms of XRCC3 Thr241Met gene and susceptibility to gastric cardia and/non-cardia gastric cancer, and to investigate the combined effect between genes and surrounding environment.</p><p><b>METHODS</b>A case-control study with respective control group was conducted. Genotypes were investigated by PCR-RFLP. Unconditional logistic regression models were used to estimate odd ratios (ORs) and their 95% confidence intervals(95% CI).</p><p><b>RESULTS</b>The frequency of XRCC3 CC, CT and TT genotypes were 43.2%, 46.5% and 10.3%, respectively in cardia cancer cases and 53.2%, 40.9% and 5.8% respectively in non-cardia gastric cancer cases while 59.6%, 35.1%, 5.3%, respectively in control group. Variated genotypes (CT and TT) increased the risk of cardia cancer after adjusting for potential confounders (OR = 1.76, 95% CI: 1.07-2.90). On cardia cancer risks, there seemed combined effects between variated genotype and high rate of alcohol drinking, low intake of fresh vegetables and having chronic gastritis. Combined effects between variated genotype and smoking, having chronic gastritis were observed in non-gastric cancer group.</p><p><b>CONCLUSION</b>XRCC3 variated genotype was one of the risk factors of cardia cancer while different risks of factors might exsit between cardia and non-cardia gastric cancer.</p>