[Glutathione S-transferase M1, T1 genotypes and the risk of esophageal cancer: a case-control study].

To examine the association between genetic polymorphisms of glutathione S-transferase (GST) M1 and T1 and susceptibility to esophageal cancer, a multiplex polymerase chain reaction method was used to detect the presence or absence of the GSTM1 and GSTT1 genes in genomic DNA isolated from surgically removed esophageal tissues or scraped esophageal cells from cases with cancer (n = 45), cases with severe hyperplasia (n = 45), and sex/age matched normal controls (n = 45) from a high risk area, Linxian, China. Results showed that the frequency of the GSTM1-null genotype in cancer cases (44.4%) or hyperplasia cases (44.4%) was not significantly different from that in controls (46.7%). Similarly, no statistically significant differences were observed in the frequency of GSTT1-null genotype in cancer cases (40.0%) or hyperplasia cases (37.8%) when compared with the controlled population (51.1%). However, the frequency of combined GSTM1-nonnull and GSTT1-nonnull genotypes in cases with cancer (40.0%) and cases with hyperplasia (37.8%) showed a significant increase compared to that in controls (22.2%). Persons with both GSTM1 and GSTT1 positive genotypes had 4-fold risk in developing esophageal cancer (odds ratio, OR = 4.20; 95% confidence interval, CI = 1.23-14.36) and 2.6-fold risk for hyperplasia (OR = 2.64; 95% CI = 0.84-8.30), respectively. These results suggest that combined GSTM1-nonnull and GSTT1-nonnull genotypes may act as risk factor in the development of esophageal cancer in Linxian population.