OBJECTIVETo determine the interaction between indoor air pollution and mEH gene polymorphisms.

METHODSBlood samples from 222 non small cell lung cancer patients and 222 healthy people were characterized by PCR and PCR-RFLP methods. The interaction coefficients were determined through unconditional logistic regression model.

RESULTSSignificant differences in the positive rate of mEH-exon3 mutant and the heterozygote were found between case and control groups (chi(2) = 7.046, P = 0.030). But no significant difference was found in mEH-exon4 non-wild-type between groups (chi(2) = 2.674, P = 0.263). mEH-exon3 mutant (OR = 1.99; 95% CI = 1.21, 3.25) could significantly increase the risk of lung cancer. After adjusted by confounding variables, significant interactions were found between the use of coal-wall stove and the non-wild type mEH gene. The interaction coefficients were increased with the duration of exposure and quantity of coal consumed. The super multiplication models were established between non-wild type mEH gene and the exposure to soot or oil fume during cooking. The interaction coefficients were 2.75 and 7.34 respectively for exon3 and exon4. No interaction was found between non-wild type mEH gene and irritation of eye or throat during cooking.

CONCLUSIONThrough the molecular epidemiological techniques, we confirmed indoor air pollution that caused by coal burning was a noticeable lung cancer risk factor. The interaction between the polymorphisms of mEH gene and the indoor air pollution plays an important role in the carcinogenesis of lung.