Background

Glutathione S-transferase (GSTs) plays an important role in the detoxification of many xenobiotics involved in the etiology of cancer. In different ethnic groups, variations in null allele frequency have been observed. We have investigated GSTM1 gene polymorphisms in healthy subjects and lung cancer patients in the Turkish population and reviewed the control subjects of the studies performed in the Turkish population.

Methods

Following blood sampling from patients and controls, DNA samples were extracted from the whole blood and were amplified by using polymerase chain reaction (PCR) method in all of the 256 cases, consisting of 102 previously diagnosed with lung cancer and 154 healthy controls.

Results

The prevalence of GSTM1-null genotype in the lung cancer patients was 49%, compared to 52.6% in the control group (OR= 1.39, 95% CI= 0.70–1.90, p= 0.57). There were also no significant relationships in GSTM1 genotypes among histopathologic types of lung cancers (p> 0.05). The frequency of GSTM1 was found to be 41.2%(n= 1809) when the control subjects of the studies performed in Turkish population were reviewed.

Conclusion

We have observed that GSTM1 genotype is not an independent risk factor for lung cancer.

1. Background

Carcinoma of the lung is the most common cancer and the most frequent cause of death in the patients with cancer around the world [1]. Environmental carcinogens such as active and passive smoking, air pollution and environmental exposures have strong influences on individual factors [2]. In humans, there are several genetic polymorphisms of the enzymes involved in metabolic activation and detoxification of pulmonary carcinogens including polycyclic aromatic hydrocarbons (PAH) and aromatic amines. Interindividual differences in ability to activate and detoxify carcinogens are expected to affect the risk of developing lung cancer [3]. Polymorphisms of the genes encoding phase I and phase II xenobiotic metabolizing enzymes have been shown to be associated with susceptibility to lung cancer in a number of epidemiologic studies [4]. However, most of these studies are limited by lack of adequate statistical power. To overcome this limitation, the International Collaborative Study on Genetic Susceptibility to Environmental Carcinogens (GSEC) has begun and is on-going to pool raw data of studies on metabolic genetic polymorphisms and cancer risk [5].