Objective   To assess the role of GSTM1 gene as a biomarker for lung cancer susceptibility by detecting genetic polymorphisms of GSTM1 in lung cancer patients and their first degree relatives.

  Methods   Acase-control study based on family and hospital was carried out and gentic polymorphisms of GSTM1 were determined by the multi differential poly merase chain reaction(MDPCR)method.

  Results   Rates of the GSTM1 null genotype were found 71.43% (45/63), 74.19% (46/62), 53.33% (16/30)and 51.06% (24/47)among lung cancer patients, first degree relatives of lung cancer patients, benign pulmonary disease patients and health checked up persons, respectively.The prevalence rate of GSTM1 null genotype in the lung cancer group and their relatives were significantly higher than that of the health checked up group(P=0.03, 0.01, respectively).Compared with health checked up group, OR in lung cancer group was 2.40(95% CI=1.09~5.29)and in the relatives group was 2.76(95% CI=1.23~6.17).The relatives group had a significantyly higher frequency of GSTM1 null genotype than that of the hospital group(P=0.047, OR=2.51, 95% CI=1.01~6.24).Stratified analysis in lung cancer patients and the controls showed a significant interaction of smoking and GSTM1 null genotype in lung cancer risk.

  Conclusion   GSTM1 played a biomarker role in lung cancer susceptibility.