BACKGROUNDSome studies have supposed that glutathione S-transferases (GSTs) may be involved in detoxification of carcinogens, especially from tobacco smoke. Therefore, polymorphism of GSTs has been considered as potential protectors of individual cancer risk. The objective of this study is to investigate the relationship between genetic polymorphism of GSTT1 and inherent susceptibility to lung cancer in Han population in Sichuan, China.

METHODSA case-control study was carried out to compare the distribution frequency of GSTT1 gene polymorphism between lung cancer (n=150) and control healthy individuals (n=152) with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and to analyze the relationship between the GSTT1 gene polymorphism and smoking and the inherent susceptibility of lung cancer.

RESULTS(1) The distribution frequency of GSTT1(-) genotype was 54.7% (82/150) in lung cancer and 38.2% (58/152) in control group respectively (OR=1.681, 95%CI=1.009- 2.803 , P=0.046); (2) GSTT1(-) genotype remarkably increased the risk of squamous cell carcinoma (OR=2.969, 95%CI= 1.511 -5.834, P=0.002) and adenocarcinoma (OR=2.095, 95%CI=1.060-4.140, P= 0.033 ); (3) In smokers, GSTT1(-) genotype significantly increased the risk for lung cancer (OR=4.051, 95%CI=1.959-8.380 , P=0.000); (4) In people with GSTT1(-) genotype, smoking markedly increased the risk for lung cancer (OR=53.885, 95%CI=11.789-246.302, P=0.000); (5) In heavy smokers (≥20 packyears), GSTT1(-) genotype could remarkably increase the risk of lung cancer (OR=4.296, 95%CI=1.649-11.190, P=0.003).

CONCLUSIONS(1) People with GSTT1(-) genotype have significantly increased risk for lung cancer in Han population in Sichuan, China, especially for squamous cell carcinoma. (2) GSTT1(-) genotype interacts synergistically with smoking on lung cancer risk. The more the cigarettes smoke, the higher the risk of lung cancer increases in those people who are smokers with GSTT1(-) genotype.