Environmental dietary
carcinogens and genetic polymorphisms in metabolic
enzymes have been reported to be the risk factors for
gastric cancer. This study was undertaken to investigate the effects of the diet, the N-
acetyltransferase (
NAT) 2 acetylation status and their interaction on
gastric cancer risk. The study population consisted of 471
gastric cancer patients and 471 age- and sex-matched control subjects. NAT2 genotypes were identified using single-
nucleotide primer extension reaction methods. Thirty-one alleles related to 12 polymorphism sites were assayed in this study. Significantly increased odds ratios were observed in former smokers (OR = 2.39, 95% CI = 1.57-3.62), heavy drinkers (OR = 1.28, 95% CI = 1.06-1.55) and individuals who eat well-done meat (OR = 1.24, 95% CI = 1.09-1.41). The odds ratios (95% CI) for high intake of kimchi, stews and soybean
paste were 3.27 (2.44-4.37), 1.96 (1.50-2.58) and 1.63 (1.24-2.14), respectively. The NAT2 genotype alone was not associated with
gastric cancer risk. A significant gene-environment interaction was observed between
environmental carcinogens and NAT2 genotypes. The odds ratios for kimchi, stews and soybean
paste were higher in slow/intermediate acetylators than in rapid acetylators. The odds ratios for slow/intermediate acetylators were 2.28 (95% CI: 1.29-4.04) for light smokers and 3.42 (95% CI: 2.06-5.68) for well-done meat intake. The NAT2 acetylator genotype may be an important modifier of the effects of environmental factors on
gastric cancer risk.