Glutathione S-transferase M1 Gene Research Articles

Analysis of glutathione S-transferase M1 and glutathione S-transferase T1 gene polymorphisms suggests age-related relationships in a northern Italian population

The present work attempts to determine the distribution of GSTM1 and GSTT1 genotype and allele frequencies in a sample of northern Italian population, and to examine the age-related association of these polymorphisms. The frequencies of the deleted GSTM1 and GSTT1 genotypes were 0.357 and 0.169, respectively. GSTT1 null-genotype frequency found in this work further confirms data obtained in previous studies of Italian populations, while for GSTM1 deletion our sample showed a significantly lower-frequency value with respect to other Italian and European populations, with exception of the Greek. No significant differences occurred between men and women in the frequency of each gene, which could suggest that, in the studied sample, there were no sex differences in susceptibility to diseases and in detoxifying enzymes such as GSTs. In order to analyze the relationship between GSTT1 and GSTM1 gene polymorphisms and age, the sample was subdivided into four age groups: 1-30 years (n = 101); 31-50 years (n = 160); 51-79 years (n = 144) and 80-100 years (n = 58). This age-related analysis showed a decreasing gradient of GSTs null genotypes between younger and older groups, with the 80-100 age group showing a significantly lower frequency of GSTT1 null, GSTM1 null and GSTT1/GSTM1 double null genotypes with respect to the younger group.

Glutathione S-transferase and Microsomal Epoxide Hydrolase Gene Polymorphisms and Risk of Chronic Obstructive Pulmonary Disease in Slovak Population

To determine the risk of chronic obstructive pulmonary disease (COPD) associated with polymorphisms in the glutathione S-transferase (GST) M1, GST T1, and microsomal epoxide hydrolase (EPHX1) genes in a cohort of Slovak population. Two hundred and seventeen patients with the diagnosis of COPD and 160 control subjects were enrolled in the study. Blood samples were collected from all subjects and the DNA from peripheral blood lymphocytes was used for subsequent genotyping assays, using polymerase chain reaction and restriction fragment-length polymorphism methods. In an unadjusted model, an increased risk for COPD was observed in subjects with EPHX1 His113-His113 genotype (odds ratio [OR], 2.32; 95% confidence interval [CI], 1.20-4.69; P=0.008), compared with the carriers of the Tyr113 allele. However, after the adjustments for age, sex, and smoking status, the risk was not significant (adjusted OR, 1.79; 95% CI, 0.91-3.53; P=0.093). In a combined analysis of gene polymorphisms, the genotype combination EPHX1 His113-His113/GSTM1 null significantly increased the risk of COPD in both, unadjusted (OR, 5.08; 95% CI, 1.70-20.43; P=0.001) and adjusted model (OR, 4.87; 95% CI, 1.57-15.13; P=0.006). Although none of the tested gene polymorphisms was significantly related to an increased risk of COPD alone, our results suggest that the homozygous exon 3 mutant variant of EPHX1 gene in the combination with GSTM1 null genotype is a significant predictor of increased susceptibility to COPD in the Slovak population. The findings of the present study emphasize the importance of detoxifying and antioxidant pathways in the pathogenesis of COPD.

Polymorphisms in glutathione S-transferase M1 and T1 (GSTM1 and GSTT1) genes in the indigenous and the nonresident population of the Kemerovo region

GSTM1 and GSTT1 gene polymorphisms were studied in Shorians, Teleuts, and Caucasians of the Kemerovo region. It has been shown that distribution of homozygous deletions in the examined groups is significantly heterogeneous. The frequency of deletion genotypes and combinations of deletion in these genes was lower in Shorians and, Teleuts than in Caucasians.

Effect of dietary allyl isothiocyanate from Brassica vegetables on serum glutathione S‐transferase‐α concentration

Allyl isothiocyanate (AITC) is a possible anticancer agent derived from foods including brown mustard and green cabbage. In a crossover study, 12 men and 34 women participated in 3 treatment phases, which consisted of an 11‐day basal diet supplemented as follows: 1) 11.4 mg AITC, 2) 100 g pureed cabbage + 30 g brown mustard (CM), 3) unsupplemented control. Subjects were selected by genotype for glutathione S‐transferase (GST) M1 and DNA repair enzyme gene XPD. Blood samples were collected on day 1 (baseline) and day 11, and outcome measures included COMET, 8‐oxo‐dG, F2‐isoprostanes, IL6, VEGF, GST activity, and GST‐α concentration. The mustard AITC content unexpectedly decreased over time. The response of log GST‐α concentration to treatment was proportional to baseline values, but the magnitude of the response was higher for subjects on the AITC treatment. Consumption of the CM treatment resulted in increased log GST‐α concentration independent of baseline value. Evaluation of other outcome measures and the effect of genotype on treatment response is underway. Funded by USDA/ARS and NIH/NCI.

Glutathione S-Transferase M1 (GSTM1) Polymorphisms and Lung Cancer: A Literature-based Systematic HuGE Review and Meta-Analysis

Multiple genes have been studied for potential associations with lung cancer. The gene most frequently associated with increased risk has been glutathione S-transferase M1 (GSTM1). The glutathione S-transferase enzyme family is known to catalyze detoxification of electrophilic compounds, including carcinogens, therapeutic drugs, environmental toxins, and products of oxidative stress. In this review, the authors summarize the available evidence associating lung cancer with the GSTM1 gene. They describe results from an updated meta-analysis of 98 published genetic association studies investigating the relation between the GSTM1 null variant and lung cancer risk including 19,638 lung cancer cases and 25,266 controls (counting cases and controls in each study only once). All studies considered, the GSTM1 null variant was associated with an increased risk of lung cancer (odds ratio (OR) = 1.22, 95% confidence interval (CI): 1.14, 1.30), but no increase in risk was seen (OR = 1.01, 95% CI: 0.91, 1.12) when only the five largest studies (>500 cases each) were considered. Furthermore, while GSTM1 null status conferred a significantly increased risk of lung cancer to East Asians (OR = 1.38, 95% CI: 1.24, 1.55), such a genotype did not confer increased risk to Caucasians. More data regarding the predictive value of GSTM1 genetic testing are needed before population-based testing may be reasonably considered.

Polymorphisms of GSTM1 and CYP1A1 genes and their genetic susceptibility to prostate cancer in Chinese men

Variation in prostate cancer incidence between different racial groups has been well documented, for which genetic polymorphisms are hypothesized to be an explanation. We evaluated the association between polymorphisms in the cytochrome P-450 CYP1A1 (CYP1A1) and glutathione S-transferase M1 (GSTM1) genes and genetic susceptibility to prostate cancer in Chinese men. Two hundred and eight prostate cancer patients and 230 age matched controls were enrolled in this study. All DNA samples from peripheral blood lymphocytes were genotyped for common genetic polymorphisms of the CYP1A1 and GSTM1 genes using the oligonucleotide microarray (DNA chip) technique and the polymorphism results confirmed by sequencing. The different polymorphisms in prostate cancer patients were also analyzed according to age at diagnosis, prostate specific antigen level, cancer stage and grade (Gleason score). The prevalence of the GSTM1 (0/0) genotype was significantly higher in prostate cancer patients (58.2%) than in controls (41.7%, P<0.05). Further analysis demonstrated that the prostate cancer patients with a GSTM1 (0/0) genotype were younger than those with the GSTM1 (+/+) genotype (P=0.024). No significant differences in the frequency distributions of CYP1A1 polymorphisms were observed between prostate cancer patients and controls. GSTM1 (0/0) gene polymorphism may be linked to prostate cancer risk and early age of onset in Chinese.

Association of GSTM1 and GSTT1 gene polymorphisms with coronary artery disease in relation to tobacco smoking

Recent studies suggest that the common variant in the glutathione S-transferase (GST) M1 (GSTM1) and T1 (GSTT1) gene is associated with the risk of smoking-related coronary artery disease (CAD). Intra-ethnic as well as inter-ethnic differences are known to impact the frequencies of GST gene polymorphisms, thus influencing its interactive effect with tobacco smoking on CAD risk. The aim of the present study was to evaluate the interaction of the genetic polymorphisms of GSTM1 and GSTT1 with cigarette smoking and the risk of CAD in a Chinese population. We conducted a study with 277 CAD patients and 277 controls matched by age and sex to examine the prevalence of GSTM1 and GSTT1 polymorphism in CAD. We found that homozygous deletion of GSTM1 had a frequency of 32.1% among patients with CAD and 21.3% among those without CAD (p=0.004). The frequency of the GSTT1(null) genotype was 27.8% among the patients with CAD and 19.1% among CAD-free subjects (p=0.016). Patients who smoked having both the wild-type genotypes of GSTM1 and GSTT1 were protected from developing coronary heart disease (p<0.001). Moreover, smokers with combined GSTM1(null)GSTT1(null) genotypes had a significantly higher number of stenosed vessels than those with the positive genotype (p=0.02). Our results suggest that GST polymorphisms may be a susceptibility factor to smoking-related CAD in the Chinese population.

An association study of sodium-lithium countertransport activity with glutathione S transferase (GST) T1 and GST M1 null polymorphisms in Greek dyslipidaemic patients and controls

Previous genomic linkage studies have produced evidence linking sodium-lithium countertransport activity (Na/Li CT) with various chromosomal regions including loci harbouring glutathione S transferase (GST) genes. The aim of this study was to examine the putative association of erythrocyte Na/Li CT activity with GST T1 and M1 gene null polymorphisms. Na/Li CT activity was determined in erythrocytes isolated from 85 individuals, using a standard assay procedure employing atomic absorption spectroscopy. Genotyping of the GST T1 and GST M1 null polymorphisms was accomplished with a multiplex PCR method. A general linear model using age, sex, smoking, dyslipidaemia and hypertension as covariates was used to examine the association of Na/Li CT activity with the GST T1 and GST M1 genotypes. Individuals with the GST T1 null genotype displayed marginally significantly (p=0.049) lower values of Na/Li CT activity compared to those harbouring at least one copy of the GST T1 gene. The significance of this association was eliminated following adjustment for covariates (p=0.150), but survived as a trend when the sample was limited to normotensive and normolipidaemic individuals (p=0.070). No association was detected between the GST M1 null polymorphism and Na/Li CT activity. The suggestive association of the GST T1 null polymorphism with erythrocyte Na/Li CT activity is in line with previously published data from genetic linkage and biochemical analyses and may be of potential prognostic value as regards the behaviour of the countertransport and the development of related pathologies under conditions of oxidative insult.

Impact of Glutathione S-Transferase M1 and T1 Gene Polymorphisms on the Smoking-Related Coronary Artery Disease

Glutathione S-transferase (GST) plays a key role in the detoxification of xenobiotic atherogen generated by smoking. To analyze the effect of GSTM1/T1 gene polymorphisms on the development of smoking-related coronary artery disease (CAD), 775 Korean patients who underwent coronary angiography were enrolled. The subjects were classified by luminal diameter stenosis into group A (>50%), B (20-50%), or C (<20%). GSTM1 and GSTT1 gene polymorphisms were analyzed using multiplex polymerase chain reaction (PCR) for GSTM1/T1 genes and CYP1A1 gene for internal control. Of 775 subjects, 403 patients belonged to group A. They had higher risk factors for CAD than group B (N=260) and group C (N=112). The genotype frequencies of null GSTM1 and GSTT1 showed no significant differences among 3 groups. Considering the effect of GSTM1 gene polymorphisms on the smoking-related CAD, smokers with GSTM1 null genotype had more increased risk for CAD than non-smoker with GSTM1 positive genotype (odds ratios [OR], 2.07, confidence interval [CI], 1.06-4.07). Also the effect of GSTT1 gene polymorphism on smoking-related CAD showed the same tendency as GSTM1 gene (OR, 2.00, CI, 1.05-3.84). This effect of GSTM1/T1 null genotype on smoking-related CAD was augmented when both gene polymorphisms were considered simultaneously (OR, 2.76, CI, 1.17-6.52). We concluded that GSTM1/T1 null genotype contributed to the pathogenesis of smoking-related CAD to some degree.

Glutathione S-Transferase Gene Polymorphism and Heart Iron Overload in Thalassemia Major.

Heart is the target lethal organ for iron accumulation in thalassemia major. Currently, magnetic resonance imaging (MRI) is the only non-invasive method with the potential to assess myocardial iron. MRI T2* has proven to be a fast, simple, robust and clinically useful tool for the assessment of cardiac iron load. In chelated patients, myocardial iron is usually inversely related to compliance with chelation while there is no meaningful correlation with liver iron and serum ferritin concentration measured at the time of T2* assessment. However, in a subset of patients, myocardial iron overload occurs despite an history of good compliance with chelation therapy, suggesting the possible role of genetic factors. Several gene polymorhisms including apolipoprotein epsylon and HLA haplotypes have been described as protective or predisposing factors for cardiac iron dysfunction. Wu et al. (2006) analyzed polymorphisms of two endogenous antioxidant enzymes, glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1). They found that the GSTM1 null (deleted) genotype was associated with a decreased signal intensity ratio on MRI, suggesting that genetic variations of the GSTM1 enzyme are associated with cardiac iron deposition. The aim of the current study was to evaluate if the GSTM1 null genotype is a predisposing factor for myocardial iron overload in thalassemia major patients on chelation treatment with desferrioxamine with low body iron load as assessed by serum ferritin levels. Allelic distribution of wild and null GSTM1 genotype was assessed in 24 patients with thalassemia major in whom the severe myocardial iron overload (T2* <10 msec) was unexpected based on low body iron load (mean of lifelong serum ferritin determinations 1360 ± 268 ng/ml), and in 26 thalassemia patients in whom the myocardial iron overload was expected based on high body iron load (mean of lifelong serum ferritin determinations 4724 ± 1530 ng/ml). Twenty-six healthy subjects were analyzed as controls. We found that the GSTM1 null genotype was more frequent in thalassemia patients with unexpected myocardial iron load (p=0.02) than in patients with expected myocardial iron load (Table 1). The presence of the GSTM1 null genotype can therefore explain in part the development of severe myocardial iron overload in thalassemia major patients who have been adequately chelated since their first years of life. Based on the inhibition of the cardiac ryanodine receptor calcium channels by members of the glutathione transferase structural family, and given the little difference in permeability among divalent cations in those channels, we hypothesized that the deletion of GSTM1 is associated with increased entry of iron into the myocites, in patients with thalassemia major. Further studies are needed to understand the mechanisms that underlie the association between GSTM1 gene polymorphisms and predisposition to myocardial iron overload.Table 1Allelic distribution of wild and null GSTM1 genotype in beta thalassemia patients with expected and unexpected heart iron overload, and in 26 healthy controlsGSTM1 wildGSTM1 wildGSTM1 nullGSTM1 nulln%n%A. Thalassemic patients with expected heart iron overload1765.4934.6B. Thalassemic patients with unexpected heart iron overload833.31661.5C. Healthy controls1661.51038.4χ2 test : A vs C p>0.05; A vs B p=0.02; B vs C p=0.04

CYP1A1 and GSTM1 polymorphisms and lung cancer risk in Chinese populations: A meta-analysis

Genetic polymorphisms of cytochrome p450 (CYP1A1) and glutathione S-transferase M1 (GSTM1) genes are thought to have significant effects on the metabolism of environmental carcinogens and thus on cancer risk, but the reported results are not always consistent. In this meta-analysis, we assessed reported studies of associations between polymorphisms of these two genes and risk of lung cancer in Chinese populations. Through a systematic literature search for publications between 1989 and 2006, we summarized the data from 46 studies on polymorphisms of MspI and exon7-Val of CYP1A1 and GSTM1 and lung cancer risk in Chinese populations, and found that compared with the wild-type homozygous genotype (type A), lung cancer risk for the combined variant genotypes (types B and C) was 1.34-fold (95% confidence interval [CI]=1.08-1.67) (Z=2.64, P=0.008); the risk for the combined variant genotypes (Ile/Val and Val/Val) of CYP1A1 exon7 was 1.61-fold (95% CI=1.24-2.08) (Z=3.62, P<0.001), compared with the Ile/Ile genotype; and that the risk for the GSTM1 null genotype was 1.54-fold (95% CI=1.31-1.80) (Z=5.32, P<0.001), compared with the GSTM1 present genotype. Therefore, in 46 published studies in Chinese populations, we found evidence of an association between the CYP1A1 variant and GSTM1 null genotypes and increased risk of lung cancer.

Possible aggravating impact of polychlorinated biphenyls, phthalate esters and glutathione s-transferase m1 gene null polymorphism in south indian women with endometriosis

Expression of compound metabolic enzymes is determined by polymorphism and may predispose the development of diseases aggravated by environmental factors. Glutathione S-transferase M1 (GSTM1) is an important phase II enzyme involved in the detoxification of many environmental carcinogens. GSTM1 status has been extensively studied as a risk factor for endometriosis, although inconsistent associations have been observed. To re-examine this controversy we designed a case-control study to determine the possible association between polychlorinated biphenyls (PCBs), phthalate esters (PEs) and GSTM1 null (∗0/∗0) mutation in the etiology of endometriosis.

Association between susceptibility to advanced stage endometriosis and the genetic polymorphisms of aryl hydrocarbon receptor repressor and glutathione-S-transferase T1 genes

This study was performed to determine whether genetic polymorphisms of aryl hydrocarbon receptor repressor (AhRR), glutathione-S-transferase M1 (GSTM1) and glutathione-S-transferase T1 (GSTT1) are associated with susceptibility to advanced stage endometriosis in a Korean population. This study comprised 316 women with advanced stage endometriosis and 256 control women without endometriosis. Genotyping of the AhRR codon 185 was performed by real-time polymerase chain reaction (PCR) analysis. GSTM1 and GSTT1 genotyping for gene deletions were carried out by multiplex PCR analysis. G allele frequency at codon 185 of AhRR was increased in patients with endometriosis (P=0.047), and there was a trend for an association of C/G+G/G genotypes with risk of endometriosis (P=0.06). The proportion of null mutation at GSTT1 also tended to increase (P=0.06) in patients with endometriosis, whereas there was no difference in the genotype distribution of GSTM1 genes. Analyzing AhRR and GSTT1 together, we found that patients with high-risk genotypes at both loci have increased risk of endometriosis, compared with patients without high-risk genotypes (P=0.015). These findings suggest that the AhRR codon 185 and GSTT1 polymorphisms are associated with the risk of advanced stage endometriosis.

Glutathione-S-transferase M1 and T1 Genetic Polymorphisms and the Risk of Cataract Development: A Study in the Turkish Population

In this study, we aimed to determine the effects of genetic polymorphisms of glutathione-S-transferase M1 (GSTM1) and glutathione-S-transferase T1 (GSTT1) on risk of developing different subtypes of age-related cataract in the Turkish population. Using a multiplex polymerase chain reaction (PCR), GSTM1 and GSTT1 gene polymorphisms were analyzed in 195 patients with age-related cataract (75 patients with cortical, 53 with nuclear, 37 with posterior subcapsular, and 30 with mixed type) and in 136 patients of an otherwise healthy control group of similar age. GSTM1 null genotype had a significant association with the development of cataract in female subjects (p < 0.0029; OR, 2.98; 95% CI, 1.41–6.34). This relationship in female subjects was only in nuclear and mixed types cataract cases (p < 0.002; OR, 4.58; 95% CI, 1.67–12.78 and p < 0.03, respectively). There was also a statistically significant association between the combination of GSTM1-null and GSTT1-positive genotypes and the risk of cataract development in female subjects (p = 0.01; OR = 2.87; 95% CI = 1.25–6.69). Stratification by the subtypes revealed that this association was only in nuclear type cataract (p = 0.001; OR, 3.92; 95% CI, 1.34–11.71). GSTM1-null genotype or combination of the GSTM1-null and GSTT1-positive genotypes in females may be associated with increased risk of cataract development in the Turkish population.

Glutathione S-transferase M1 and GST T1 genetic polymorphisms and Raynaud’s phenomenon in French vinyl chloride monomer-exposed workers

Occupational vinyl chloride monomer (VCM) exposure can induce Raynaud's phenomenon (RP). However, not all VCM workers developed RP, which suggests an underlying genetic susceptibility. Genetic polymorphisms of glutathione S-transferases (GSTs), involved in VCM metabolism, have been shown to influence certain VCM-related health effects. We have conducted a case-control study of 58 subjects with RP along with 247 subjects without RP, from a population of 305 French workers exposed or formerly exposed to VCM, to assess any association between GST M1 and GST T1 gene polymorphisms, either separately or in combination, and the presence of RP. None of the GST M1 or GST T1 genotypes were significantly associated with the presence of RP among studied VCM workers. A combination of positive genotypes for both GST M1 and GST T1 was significantly associated with RP presence, compared to the other combinations of genotypes (OR=2.1, 95% CI=1.1-3.8). OR adjusted for age, smoking status, alcohol consumption and history of treated hypertension did not reach significance (OR=2.0, 95% CI=0.9-5.2). None of the GST M1 and GST T1 genotypes seem to contribute separately to the presence of RP, suggesting that they are not, when taken alone, a major determinant of interindividual variability for VCM-induced PR. However, the combination of both positive GST M1 and GST T1 genotypes appears to contribute slightly to susceptibility to RP in VCM-exposed subjects. Nevertheless, our study-the first to examine the role of a genetic component in the occurrence of RP secondary to occupational exposure to a chemical-corroborates the previous considerations that interaction between the genetic constitution and environmental factors is of importance in determining the health-adverse effects of VCM exposure.

Prospective study of fetal DNA in serum and disease activity during pregnancy in women with inflammatory arthritis

Rheumatoid arthritis (RA) usually improves during pregnancy and recurs postpartum. Fetal cells and cell-free DNA reach the maternal circulation during normal pregnancy. The present study investigated dynamic changes in levels of fetal DNA in serum from women with RA and inflammatory arthritis during and after pregnancy to test the hypothesis that the levels of circulating fetal DNA correlate with arthritis improvement. Twenty-five pregnant patients were prospectively studied. A real-time quantitative polymerase chain reaction panel targeting unshared, paternally transmitted HLA sequences, a Y chromosome-specific sequence, or an insertion sequence within the glutathione S-transferase M1 gene was used to measure cell-free fetal DNA. Results were expressed as fetal genomic equivalents per milliliter (gE/ml) of maternal serum. Physical examinations were conducted during and after pregnancy. Levels of fetal DNA in women with improvement in or remission of arthritis were higher than those in women with active disease, especially in the third trimester. Overall, an inverse relationship between serum fetal DNA levels and disease activity was observed (P < 0.001). Serum fetal DNA increased with advancing gestation, reaching median levels of 24 gE/ml (range 0-334), 61 gE/ml (range 0-689), and 199 gE/ml (range 0-2,576) in the first, second, and third trimesters, respectively, with fetal DNA clearance observed postpartum. Arthritis improvement was initially noted in the first trimester for most patients, increased further or was sustained with advancing gestation, and was active postpartum. Changes in serum fetal DNA levels correlated with arthritis improvement during pregnancy and recurrence postpartum. Immunologic mechanisms by which pregnancy might modulate RA activity are described.

Different susceptibility to peroxisome proliferator‐induced hepatocarcinogenesis in rats with polymorphic glutathione transferase genes

Although peroxisomal bifunctional enzyme (enoyl-CoA hydratase/L-3-hydroxyacyl-CoA dehydrogenase; BE) is a positive marker for peroxisome proliferation, it is completely absent or expressed very weakly in rat hepatic preneoplastic and neoplastic lesions induced by peroxisome proliferators (PP). After administration of PP for 8-15 weeks, some rats exhibit BE-negative preneoplastic foci but other rats do not. In the present study, to investigate the involvement of glutathione S-transferase (GST) M1 gene polymorphism in interindividual differences in susceptibility to PP, we developed a method to determine the genotypes of rats. We then examined whether rats with one type encoding 198Asn-199Cys (NC-type) or another encoding 198Lys-199Ser (KS-type) exhibit differences in clofibrate (CF) susceptibility. After administration of 0.3% CF for 6 weeks or more, BE-negative foci were found immunohistochemically in KS/KS-type rats, but not in NC/NC-type rats. The number of BE-negative foci in KS/KS rats was 15.3 +/- 9.0 foci/cm2 of liver section after 6 weeks of CF administration, and the values did not alter thereafter. The mean areas of BE-negative foci in KS/KS rat livers increased during the period from 6 to 60 weeks. At weeks 30 and 60, almost all BE-negative foci exhibited a clear cell phenotype, a type of preneoplastic hepatic lesion. BE-negative foci were devoid of peroxisome proliferator-activated receptor alpha, whereas surrounding tissues were positive for the receptor. These results indicate that rats that are polymorphic for the GST M1 gene exhibit different susceptibilities to CF in vivo.

Deletion polymorphism of the GSTM1 gene in lung cancer patients from the Lake District in Turkey

20089 Background: Association of glutathione-S-transferase M1 (GSTM1) polymorphisms and cancer has been demonstrated. Especially the deletion polymorphism of GSTM1 has been related to risk for lung cancer in some studies. We thus investigated the frequency of GSTM1-null genotype in lung cancer patients and healthy individuals from the Lake District in Turkey. Methods: Cases were recruited among patients with clinically and histologically confirmed diagnosis of lung cancer patients from the Lake District. Controls were selected among the nonsmoking healthy blood donors applied to hospital in same region. DNA samples were extracted from whole blood using proteinaz K (20 mg/mL) digestion in lysis buffer (10 mM Tris-HCl, 400 mM NaCl, 2 mM EDTA, % 10 SDS). Homozygous deletion of the GSTM1 gene was determined by PCR using the primers E4F: 5′-CTGCCCTACTTGATTGATGGG-3′, E5R: 5′-CTGGATTGTAGCAGATCATGC-3′, corresponding to exons 4 and 5 of the GSTM1 gene. PCR products were analyzed by 1% agarose gel electrophoresis and UV transilluminator was then used to evaluate the product content. Individuals carrying the GSTM1 gene were identified by the presence of a 273 bp DNA fragment. Results: The study comprised 30 patients and 30 controls. The frequency of GSTM1-null genotype was found to be (n = 14) 46.7% in lung cancer patients and (n = 5) 16.6% in controls. The difference was statistically significant (Fisher’s chi square test: 4.80, P: 0.0251). Conclusion: We found an increased incidence of GSTM1-null genotype among lung cancer patients, indicating that the GSTM1 absence is associated with a slightly increased lung cancer risk in people from the Lake District in Turkey. No significant financial relationships to disclose.

The 262T>C promoter polymorphism of the catalase gene is associated with diabetic neuropathy in type 1 diabetic Russian patients

Oxidative stress plays an important role in the development of diabetic neuropathy (DN). Antioxidant enzymes reduce enhanced oxidative stress in the peripheral nerve. Genetic variations within the antioxidant genes therefore could be implicated in the pathogenesis of DN. Using a PCR-RFLP assay, a total of 216 Russian type 1 diabetic (T1D) patients with DN and 250 T1D individuals without DN have been tested to verify whether the -262T > C and 1167C > T polymorphisms of the catalase (CAT), 197Pro > Leu amino acid substitution of the glutathione peroxidase 1 (GPX1) and +/null polymorphism of the glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) genes contribute to susceptibility to DN. Association between the -262T > C polymorphism of the CAT gene and DN was shown. The -262TT genotype of the CAT gene was significantly associated with higher erythrocyte catalase activity in blood of DN patients compared to the -262CC genotype (17.8 +/- 2.7 x 104 IU/g Hb vs. 13.5 +/- 3.2 x 104 IU/g Hb, P = 0.0022). These data suggest a protective role of the -262T allele of the CAT gene against the rapid development of DN in T1D (Odds Ratio = 0.7 [95% confidence interval 0.54-0.9], P = 0.002).

Distribution of glutathione S-transferase M1, P1 and T1 genotypes in different age-groups of Finns without diagnosed cancer

Background: Xenobiotic metabolizing enzymes (XMEs) are important detoxifiers of hazardous environmental agents, and their polymorphisms may therefore modify the risk of environmentally induced cancers. Consequently, the XME polymorphisms have been extensively studied in this context during recent years. Particular attention has been given to the polymorphisms of glutathione S-transferase (GST) M1, P1 and T1 genes. Previous studies have provided abundant data indicating these polymorphisms as important modifiers of individual susceptibility to cancers of environmental origin. It can be postulated that if the at-risk genotypes of these genes were real risk factors for the environmental cancers, their prevalence would presumably decrease with age in cancer-free part of the population. Methods: We tested the hypothesis in a population based group of 2105 Finns (1051 men, 1054 women) in five age strata (27, 37, 47, 57 and 67 years of age), all without clinically diagnosed cancer. Results: For GSTM1 genotype, a significant interaction was seen between gender and age among never smokers ( p = 0.003). Currently smoking men tended to be less likely (OR 0.57, 95% CI 0.31–1.03), and currently smoking women more likely (OR 1.70, 95% CI 0.97–2.97) homozygotes for the GSTP1*B allele compared with never smokers. Moreover, the likelihood of being a concurrent carrier of the putatively protective genotypes of all of the three studied GSTs was almost three-fold (OR 2.80, 95% CI 1.10–7.12) in heavy smokers in the two oldest age-groups compared with the other genotypes. Conclusions: Our findings based on a novel study design provide support to the previous case–control studies suggesting that GST genotypes modify individual risk of environmentally-induced cancers.