Effect of the Genetic Polymorphism of N-acetyltransferase 2 and Diet on the Carcinogenesis of Gastric Cancer in Koreans

ABSTRACT

PURPOSE: According to the recent studies on the carcinogenic factors of gastric cancer in Koreans, dietary factors, such as stew, roasted fish, and fish boiled in soy with spices, salted foods, as well as smoking, might be risk factors of gastric cancer. N-acetyltransferase 2 (NAT2) is an enzyme that plays a role in the reduction of the toxicity of various carcinogens. There is a possibility that the genetic polymorphism of NAT2 might change a subject's susceptibility to gastric cancer. The aim of this study was to examine the effects of diet, the genetic polymorphism of NAT2 and their interaction on the risk of gastric cancer in Koreans. METHODS: The subjects of this case-control study were 214 gastric cancer patients, and 214 controls, who were admitted at the Chungbuk National or Eulji University Hospitals. Each subject was directly interview, by an experienced interviewer, with a structured questionnaire. A NAT2 genetic polymorphism analysis was performed, with a PCR-RFLP technique, and the data analyzed using the PC-SAS software package. RESULTS: Increased intakes of makkoli, soybean paste stew, kimchi and ggakdugi, soy milk, chicken boiled with rice and boiled chicken were all associated with an increased risk of gastric cancer, whereas those of fermented soybean stew, Welsh onion or leek, onions, peaches, chestnuts or gingko nuts, fatsia shoots, raw fish, salted seafood and laver were all associated with a decreased risk of gastric cancer. The odds ratio (95% confidence interval) for gastric cancer for the rapid acetylators was 1.64 (1.12, 2.41), which was statistically significant. With respect to the rapid acetylators, makkoli, kimchi and soy milk were significant risk factors, and Welsh onion/leek and onions were protective factors for gastric cancer. Whereas, soybean paste stew was a risk factor of gastric cancer with the slow or intermediate acetylators. CONCLUSION: These results suggest the genotype of a rapid acetylation is a risk factor of gastric cancer, and the effects of diet on the risk of gastric cancer vary according to the genotype of the NAT2 enzyme.