Objective: To investigate the distribution of polymorphism of glutathione S-transferase P1 (GSTP1) in different kinds gastric intestinal metaplasia (IM), and the carcinogenesis risk of different types of IM.
Methods: Peripheral blood samples were collected from 87 gastric cancer patients, 87 intestinal metaplasia patients, and 87 healthy persons as controls. Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were used to analyze the distribution of different alleles of GSTP1. Biopsy specimens of gastric mucous membrane were collected by gastroscopy. Histochemical staining for mucin was used to identify the kinds of IM.
Results: The G allele rates of the IM and gastric cancer groups were both significantly higher than that of the control group (chi2=6.921, P=0.009; chi2=28.787, P=0.000). The risk of IM of those with G allele was 1.944 times higher then that of the normal controls (95% CI: 1.177-3.209), and the risk of gastric cancer of those with G allele was 3.605 times higher (95% CI: 2.217-5.863). The G allele rate of the gastric cancer group was significantly higher than that of he IM group (chi2=7.687, P=0.006). The G allele rates of the type II and III IM were significantly higher than that of the normal controls (chi2=9.981, P=0.001; chi2=8.845, P=0.002). The risk of type II IM of the subjects with G allele was 2.747 times higher than that of the normal controls (95% CI: 1.475-5.114), and the risk of type III IM of the subjects with G allele was 3.451 times higher (95% CI: 1.556-7.657). The risks of type IIIM, type III IM, and gastric cancer of the subjects with allele G of GSTP1 gene were 2.905, 3.650, and 3.813 times higher than those of the normal controls respectively (95% CI: 1.341-6.293, 1.455-9.153 and 1.953-7.444 respectively).
Conclusion: The individuals with G allele show an increased risk of developing IM and gastric cancer, especially type II and III IM. IM patients with G allele have the genetic characteristics similar to those of gastric cancer, so they should be regarded as high-risk individuals of gastric cancer and followed up regularly.