ABSTRACT
Objective To estimate the relative risk for lung cancer associated with genetic polymorphism of T6235C mutation in 3' non-coding region (Msp Ⅰ) of cytochrome P450 1A1 (CYP1A1) and glntathione S-transferase M1 (GSTM1) in the Mongolian population in Inner Mongolian Region of China. Methods Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and multiplex PCR methods were used to analyze blood samples obtained from 263 case subjects and 263 control subjects to determine their genotypes for CYP1A1 and GSTM1.Control subjects were matched with case subjects by ethnic background, age and gender. Results The frequencies of the variant CYP1A1 genotypes (CYP1A1C) and GSTM1-null in lung cancer groups were higher than those in control groups (38.4% vs. 28. 5% and 57.8% vs. 48.0%). The individuals who corried with CYP1A1C genotype had a significantly higher risk of lung cancer (OR=1.56, 95% CI=1.08 to 2.25, P=0.016) than those who carried with non-variation CYP1A1 genotype. The ones who carried with GSTM1-null genotype also had a significantly higher risk of lung cancer (OR=1.49, 95% CI=1.06 to 2.10, P=0.023) than these who carried with GSTM1-present genotype.When combination of polymorphisms of CYP1A1 and GSTM1 genotypes was analyzed, the risk of lung cancer for combination of CYP1A1C and GSTM1-null genotypes was increased significantly (OR=2.084, 95e CI=1.27 to 3.42, P=0.003). Susceptibility to lung cancer was related to smoking (OR=2.10, 95% CI=1.48 to 2.98, P=0.000). Considering smoking status, the risk of lung cancer for combination of smoking and CYP1A1C genotype was remarkably increased (OR=2.76, 950/0 CI=1.74 to 4. 37, P=0.000). It was the same case with combination of smoking and GSTM1-null genotype (OR=4. 38, 95% CI=2.35 to 8.15, P=0.000). Conclusion The polymorphisms of CYP1A1C genotype and GSTM1-null are the risk factors of lung cancer in the Mongolian population in Inner Mongolia Region of China. Smoking is also related to susceptibility to lung cancer. There may be a synergetic interaction between CYP1A1C and GSTM1-null in the elevated susceptibility of lung cancer. Smoking may have a synergetic interaction with CYP1A1C and GSTM1-null in the elevated susceptibility of lung cancer.