POSTER NO: 444

The relation between the loss of glutathine-sulfer-transferase gene with smoking and lung cancer

Baosen Pang
The Capital Medical University Affiliated Beijing Chaoyang Hospital, The Beijing Institute of Pulmonary Disease, 8 Baijiazhuang Road, Chaoyang District, Beijing, P.R. China

It is well known that smoking is one of the main causes of lung cancer but how the lung cancer is caused by smoking is not very clear. Glutathione S-transferase M1(GSTM1) plays an important role in detoxifying the carcinogens, such as benzo(a)pyrene in the tobacco smoke. It has been demonstrated that genetic deficiency of this isozyme occurs in approximately half of the population and may relate to an enhanced risk of lung cancer. In this study, we analyzed the deletion rate of the GSTM1 gene from 89 cases of patients with primary lung cancer by duplex polymerase chain reaction and hot start technique, and compared it with the rates of 106 newborns and 210 healthy adults. The deletion rates were 47.17%, 44.76% and 61.80% in the newborn group, the healthy adults group and the patients group, respectively. Odds ratio between the patients group and healthy adults group is 2.00. P value>0.01. Comparison of different histopathological groups was carried out also. The odds ratios of squamous and small cell carcinomas were 2.88, 3.70, respectively. The odds ratio of adenocarcinoma was only 0.87. When compared according to the degree of smoking we observed an odds ratio of 2.17 for the GSTM1 null genotype in relation to lung cancer risk among smokers, and the odds ratio among smokers of less than 40 pack-years was 2.37. All these show that the deletion of GSTM1 gene is interrelated with the incidence of the primary lung cancer, especially squamous and small cell carcinomas. This interrelation was more marked in persons with a lower lifetime smoking history.