Vw. Setiawan et al., GSTT1 and GSTM1 null genotypes and the risk of gastric cancer: A case-control study in a Chinese population, CANC EPID B, 9(1), 2000, pp. 73-80
Glutathione S-tranferase (GST) enzymes are involved in detoxification of ma
ny potentially carcinogenic compounds. The homozygous deletions or null gen
otypes of GSTT1 (theta class) and GSTM1 (mu class) genes may be associated
with an increased risk of cancer. Few studies have evaluated the relationsh
ip between GSTT1, GSTM1 and the risk of gastric cancer, as well as the pote
ntial interactions between these genetic markers and other risk factors of
gastric cancer in the Chinese population. We conducted a case-control study
with 143 cases with gastric cancer, 166 chronic gastritis (CG) cases and 4
33 cancer-free population controls from Yangzhong County, China, The epidem
iological data were collected by a standard questionnaire for all of the su
bjects, and blood samples were obtained from 91 gastric cancer cases, 146 C
G cases, and 429 controls. GSTT1 and GSTM1 genotypes were assayed by the PC
R method, and Helicobacter pylori infection was measured by the ELISA metho
d. Using logistic regression model in SAS, we assessed the independent effe
cts of GSTT1 and GSTM1 null genotypes on the risk of gastric cancer and the
ir potential interactions with other factors, The prevalence of GSTM1 null
genotype was 48% in gastric cancer cases, 60% in CG patients, and 51% in co
ntrols, The prevalence of GSTT1 null genotype was 54% in gastric cancer cas
es, 48% in CG patients, and 46% in controls. After controlling for age, gen
der, education, pack-years of smoking, alcohol drinking, body mass index, H
, pylori infection, and fruit and salt intake, the adjusted odds ratio (OR)
for GSTT1 and gastric cancer was 2.50 (95% confidence interval (CI), 1.01-
6.22). When gastric cancer cases were compared with CG patients, the adjust
ed OR for GSTT1 was 2.33 (95% CI, 0.75-7.25). However, GSTT1 null genotype
was not associated with the risk of CG when using population controls. No o
bvious association was found between GSTM1 and the risk of both gastric can
cer and CG, Our results suggest that GSTT1 null genotype may be associated
with an increased risk of gastric cancer in a Chinese population.