GSTM1, GSTT1, and GSTP1 polymorphism and lung cancer risk in relation to tobacco smoking

Association of GSTM1, GSTT1, and GSTP1 Ile105Val polymorphisms with risk of age-related macular degeneration: a meta-analysis

BACKGROUND

This study determined to evaluate the association between glutathione S-transferase (GST) polymorphisms, namely, GSTM1 (rs1183423000, presence/absence), GSTT1 (rs1601993659, presence/absence), and GSTP1 Ile105Val (rs1695, A>G) polymorphisms, and AMD risk.

METHODS

We searched PubMed, Embase, and Web of Science databases from January 2000 to June 2021. The odds ratio (OR) and 95% confidence interval (95% CI) were used as effect sizes. Heterogeneity was assessed using the heterogeneity metric I².

RESULTS

Five relevant studies involving 875 patients with AMD and 966 healthy controls were included in this meta-analysis, four studies concerning GSTM1 null polymorphism, four studies regarding GSTT1 null polymorphism, and four studies on GSTP1 Ile105Val polymorphism. The GSTM1 null polymorphism, GSTT1 null polymorphism and GSTP1 Ile105Val polymorphism were not significantly associated with AMD risk (OR 1.13, 95% CI 0.73-1.75, p = 0.59; OR 1.05, 95% CI 0.81-1.36, p = 0.69; OR 1.20, 95% CI 0.97-1.47, p = 0.09, respectively). There was no association between the combined GSTM1 null genotype and GSTT1 null genotype and AMD risk (OR 1.16, 95% CI 0.42-3.17, p = 0.77). Subgroup analyses revealed that the GSTM1 null genotype was associated with an increased risk of AMD in the Turkish population (OR 1.67, 95% CI 1.13-2.47, p = 0.01) and the GSTM1 null genotype was associated with a decreased incidence of non-exudative AMD (OR 0.72, 95% CI 0.52-0.99, p = 0.01). There was no obvious risk of publication bias found.

CONCLUSIONS

This meta-analysis indicated that there were no significant associations between GSTM1, GSTT1, and GSTP1 Ile105Val polymorphisms and AMD risk.

Comparative frequency distribution of glutathione S-transferase mu (GSTM1) and theta (GSTT1) allelic forms in Himachal Pradesh population

Background

Glutathione S-transferases (GSTs) are a class of important Phase II detoxification enzymes that catalyze the conjugation of glutathione and xenobiotic compounds (environmental carcinogens, pollutants and drugs) to protect against oxidative stress. GSTT1 and GSTM1 genetic polymorphisms have been extensively studied, and null genotypes or homozygous deletions have been reported in various populations. Previous studies have suggested that those who are homozygous null at the GSTM1 or GSTT1 loci are more susceptible and have a higher risk of cancers linked to environmental pollutants and drug-induced toxicity. Our study focused on GSTM1 and GSTT1 null allele frequency in the Doon population of Himachal Pradesh (India) with a comparison across other Inter and Intra-Indian ethnic groups to predict variation in the possible susceptible status.

Material and methods

Genomic DNA samples were extracted from 297 healthy unrelated individuals by a ReliaPrep™ Blood gDNA Miniprep kit (Promega, USA), and genotyped for allelic variation in GSTM1 and GSTT1 genotypes by multiplex polymerase chain reaction. Fisher's exact test was applied using SPSS.20 to analyze the genotypic distribution of GSTM1 and GSTT1 null alleles in male and female of Doon region (Solan) Himachal Pradesh.

Results

In our study, the frequency distribution of the homozygous null genotypes of GSTM1, GSTT1 individually as well as combined was found as 33.3%, 32% and 9%, respectively. Upon gender-wise comparison, a non-significant distribution (p > 0.05) for null genotypes of GSTM1 (32.8% and 35.4%, OR-0.77, 95% CI 0.42–1.41), GSTT1 (33.2% and 27.7%, OR-1.12, 95% CI 0.63–2.0) individually and combined GSTM1 and GSTT1 (10.8% and 3.7%, OR-0.31, 95% CI 0.07–1.42) were observed in studied population.

Conclusions

In our studied population, the frequency of GSTM1 null genotypes was found deviated from Inter- and Intra-Indian ethnic groups. However, the frequency of homozygous null type of GSTT1 was not significantly different, when compared to previous Indian studies, comparison with global ethnic groups showed deviation. Thus, our study has highlighted possible susceptibility risk to various xenobiotics in the Doon population of Himachal Pradesh, India.

Up-regulation of GSTT1 in serous ovarian cancer associated with resistance to TAXOL / carboplatin

Serous ovarian cancer (SOC) is the most common women cancer and the leading cause of cancer-related mortality among the gynaecological malignancies. Although effective chemotherapeutics combined with surgery are developed for the treatment, the five-year survival rate is unsatisfactory due to chemoresistance. To overcome this shortcoming of chemotherapy, we established taxol and carboplatin resistant SOC cell lines for the understandings of the molecular and cellular mechanisms of chemoresistance. Here, we found that these chemoresistant cell lines showed less viability and proliferation, due to more cells arrested at G0/G1 phase. Glutathione-S-transferases-theta1 (GSTT1) was significantly upregulated in these chemoresistant cells, along with other chemoresistant genes. Meanwhile, GSTT1 expression was also significantly upregulated in the SOC patient tissues after taxol treatment, indicating this upregulation was physiologically relevant to chemotherapy. Further, suppression of GSTT1 expression by shRNA in SOC cell lines led to more sensitivity to drug treatment, through increasing divided cells and promoting cell death. Moreover, the expression of DNA topoisomerase 1 (Topo I) was in synergy with that of GSTT1 in the chemoresistant cells, and GSTT1 can bind to Topo I in vitro, which suggested GSTT1 could function through DNA repair mechanism during chemoresistance. In summary, our data imply that GSTT1 may be a potential biomarker or indicator of drug resistance in serous ovarian cancer.

Multiple genome pattern analysis and signature gene identification for the Caucasian lung adenocarcinoma patients with different tobacco exposure patterns

Background

When considering therapies for lung adenocarcinoma (LUAD) patients, the carcinogenic mechanisms of smokers are believed to differ from those who have never smoked. The rising trend in the proportion of nonsmokers in LUAD urgently requires the understanding of such differences at a molecular level for the development of precision medicine.

Methods

Three independent LUAD tumor sample sets—TCGA, SPORE and EDRN—were used. Genome patterns of expression (GE), copy number variation (CNV) and methylation (ME) were reviewed to discover the differences between them for both smokers and nonsmokers. Tobacco-related signature genes distinguishing these two groups of LUAD were identified using the GE, ME and CNV values of the whole genome. To do this, a novel iterative multi-step selection method based on the partial least squares (PLS) algorithm was proposed to overcome the high variable dimension and high noise inherent in the data. This method can thoroughly evaluate the importance of genes according to their statistical differences, biological functions and contributions to the tobacco exposure classification model. The kernel partial least squares (KPLS) method was used to further optimize the accuracies of the classification models.

Results

Forty-three, forty-eight and seventy-five genes were identified as GE, ME and CNV signatures, respectively, to distinguish smokers from nonsmokers. Using only the gene expression values of these 43 GE signature genes, ME values of the 48 ME signature genes or copy numbers of the 75 CNV signature genes, the accuracies of TCGA training and SPORE/EDRN independent validation datasets all exceed 76%. More importantly, the focal amplicon in Telomerase Reverse Transcriptase in nonsmokers, the broad deletion in ChrY in male nonsmokers and the greater amplification of MDM2 in female nonsmokers may explain why nonsmokers of both genders tend to suffer LUAD. These pattern analysis results may have clear biological interpretation in the molecular mechanism of tumorigenesis. Meanwhile, the identified signature genes may serve as potential drug targets for the precision medicine of LUAD.

Glutathione S-transferase pi 1 variant and squamous cell carcinoma susceptibility: a meta-analysis of 52 case-control studies

Background

There are several meta-analyses on the genetic relationship between the rs1695 polymorphism within the GSTP1 (glutathione S-transferase pi 1) gene and the risk of different SCC (squamous cell carcinoma) diseases, such as ESCC (oesophageal SCC), HNSCC (head and neck SCC), LSCC (lung SCC), and SSCC (skin SCC). Nevertheless, no unified conclusions have been drawn.

Methods

Herein, an updated meta-analysis was performed to evaluate the probable impact of GSTP1 rs1695 on the susceptibility to different SCC diseases under six genetic models (allele, carrier, homozygote, heterozygote, dominant, and recessive). Three online databases, namely, PubMed, WOS (Web of Science), and Embase (Excerpta Medica Database), were searched.

Results

Initially, we obtained a total of 497 articles. Based on our selection criteria, we eventually included 52 case-control studies (9763 cases/15,028 controls) from 47 eligible articles. As shown in the pooling analysis, there was no difference in the risk of overall SCC disease between cases and controls [allele, P_a (P value of association test) = 0.601; carrier, P_a = 0.587; homozygote, P_a = 0.689; heterozygote, P_a = 0.167; dominant, P_a = 0.289; dominant, P_a = 0.548]. Similar results were obtained after stratification by race (Asian/Caucasian), genotyping, control source, and disease type (ESCC/HNSCC/LSCC/SSCC) (all P_a > 0.05).

Conclusion

The rs1695 polymorphism within the GSTP1 gene is not associated with the risk of overall SCC or a specific SCC type, including ESCC, HNSCC, LSCC, and SSCC.

Associations between prenatal lead exposure and birth outcomes: Modification by sex and GSTM1/GSTT1 polymorphism

Maternal lead exposure is associated with poor birth outcomes. However, modifying effects of polymorphism in glutathione S-transferases (GST) gene and infant sex remain unexplored. Our aim was to evaluate whether associations between prenatal lead and birth outcomes differed by maternal GST genes and infant sex. Prospective data of 782 mother-child pairs from Mothers and Children's Environmental Health (MOCEH) study were used. The genotyping of GST-mu 1 (GSTM1) and theta-1 (GSTT1) polymorphisms was carried out using polymerase chain reaction. Multivariable linear regression was used to examine whether the association between blood lead (BPb) level and birth outcomes (birthweight, length, and head circumference) varied by maternal GST genes and sex. We did not find a statistically significant association between prenatal BPb levels and birth outcomes; in stratified analyses, the association between higher BPb level during early pregnancy and lower birthweight (β=-224 per square root increase in BPb; 95% confidence interval (CI): -426, -21; false discovery rate p=0.036) was significant in males of mothers with GSTM1 null. Results were similar for head circumference model (β=-0.78 per square root increase in BPb; 95% CI: -1.69, 0.14, p=0.095), but the level of significance was borderline. Head circumference model showed a significant three-way interaction among BPb during early pregnancy, GSTM1, and sex (p=0.046). For combined analysis with GSTM1 and GSTT1, GSTM1 null and GSTT1 present group showed a significant inverse association of BPb with birthweight and head circumference in males. Our findings of the most evident effects of BPb on the reduced birthweight and head circumference in male born to the mother with GSTM1 null may suggest a biological interaction among lead, GST genes and sex in detoxification process during fetal development.

Relationship of SNP rs2645429 in Farnesyl-Diphosphate Farnesyltransferase 1 Gene Promoter with Susceptibility to Lung Cancer

Background and Purpose

The mevalonate pathway is one of the major metabolic pathways that use acetyl-CoA to produce sterols and isoprenoids. These compounds can be effective in the growth and development of tumors. One of the enzymes involved in the mevalonate pathway is FDFT1. Different variants of this gene are involved in the risk of suffering various diseases. The present study examined the relationship between FDFT1 rs2645429 polymorphism and the risk of nonsmall cell lung cancer (NSCLC) in a population from southern Iran.

Method

The genotypes of rs2645429 polymorphism of FDFT1 gene were examined in 95 samples: 34 patients with NSCLC and 61 healthy individuals by RFLP method.

Results

The results of this study indicated that C allele of this polymorphism was effectively associated with the risk of NSCLC in the Iranian population (p value = 0.023; OR = 2.71; 95% CI = 1.12–6.59) and CC genotype has significant relation with susceptibility to NSCLC (p value = 0.029; OR = 3.02; 95% CI = 1.09–8.39). This polymorphism is located in the promoter region FDFT1 gene, and CC genotype may increase the activity of this promoter. This study also found a significant relationship between C allele and metastatic status. C allele was more common in NSCLC patients. (p = 0.04).

Conclusion

C allele of FDFT1 rs2645429 polymorphism gene can be a risk factor for NSCLC, whereas T allele probably has a low protective role.

Genetic Determinants of 1,3-Butadiene Metabolism and Detoxification in Three Populations of Smokers with Different Risks of Lung Cancer

Background: 1,3-Butadiene (BD) is an important carcinogen in tobacco smoke that undergoes metabolic activation to DNA-reactive epoxides. These species can be detoxified via glutathione conjugation and excreted in urine as the corresponding N-acetylcysteine conjugates. We hypothesize that single nucleotide polymorphisms (SNPs) in BD-metabolizing genes may change the balance of BD bioactivation and detoxification in White, Japanese American, and African American smokers, potentially contributing to ethnic differences in lung cancer risk.Methods: We measured the levels of BD metabolites, 1- and 2-(N-acetyl-L-cysteine-S-yl)-1-hydroxybut-3-ene (MHBMA) and N-acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (DHBMA), in urine samples from a total of 1,072 White, Japanese American, and African American smokers and adjusted these values for body mass index, age, batch, and total nicotine equivalents. We also conducted a genome-wide association study to identify genetic determinants of BD metabolism.Results: We found that mean urinary MHBMA concentrations differed significantly by ethnicity (P = 4.0 × 10-25). African Americans excreted the highest levels of MHBMA followed by Whites and Japanese Americans. MHBMA levels were affected by GSTT1 gene copy number (P < 0.0001); conditional on GSTT1, no other polymorphisms showed a significant association. Urinary DHBMA levels also differed between ethnic groups (P = 3.3 × 10-4), but were not affected by GSTT1 copy number (P = 0.226).Conclusions:GSTT1 gene deletion has a strong effect on urinary MHBMA levels, and therefore BD metabolism, in smokers.Impact: Our results show that the order of MHBMA levels among ethnic groups is consistent with their respective lung cancer risk and can be partially explained by GSTT1 genotype. Cancer Epidemiol Biomarkers Prev; 26(7); 1034-42. ©2017 AACR.

GSTM1 polymorphism is related to risks of nasopharyngeal cancer and laryngeal cancer: a meta-analysis

Background

Accumulating data have reported that GSTM1 polymorphism may be related to nasopharyngeal cancer (NPC) and laryngeal cancer (LC). This meta-analysis was performed to investigate the relationship between GSTM1 polymorphism and risks of NPC and LC.

Methods

Pubmed, Embase, and China National Knowledge Infrastructure (CNKI) databases were searched for potential articles. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the relationship of GSTM1 polymorphism with the risks of NPC and LC. I²>50% or P<0.05 indicates significant heterogeneity. When heterogeneity existed, the random-effects model was used to pool data, otherwise, the fixed-effects model was adopted. Publication bias was detected by Begg’s funnel plot and Egger’s regression. Quality of each study was evaluated by Newcastle-Ottawa Scale.

Results

Thirty-two eligible articles were included. Pooled outcome suggested the significant relationship of GSTM1 null genotype with increased risk of LC (OR =1.28, 95% CI =1.05–1.54). Compared with hospital-based (HB) population, GSTM1 null genotype was also related to increased risk of LC (OR =1.38, 95% CI =1.06–1.80). Positive relationship of GSTM1 null genotype with enhanced risk of NPC was observed (OR =1.43, 95% CI =1.26–1.63). A similar trend was also observed in the subgroup analysis by source of control (population-based [PB]: OR =1.39, 95% CI =1.18–1.63; HB: OR =1.52, 95% CI =1.22–1.89).

Conclusion

GSTM1 null genotype is related to increased risk of NPC and LC.

Genetic polymorphism of metabolic enzymes modifies the risk of chronic solvent-induced encephalopathy

In the present study, we investigate whether genetic polymorphism in enzymes involved in the metabolism of organic solvents influences susceptibility to chronic solvent encephalopathy (CSE), which is one of the major effects of long-term exposure to organic solvents. Polymorphisms in the genes encoding CYP1A1, CYP2E1, EPHX1, GSTM1, GSTT1 and GSTP1 enzymes were determined in a group of male CSE patients ( N = 97) and controls ( N = 214). The selection of the patients was based on a standard diagnostic protocol, including interviews, neuropsychological tests and questionnaires directed to somatic, cognitive and mood symptoms and exposure, in combination with well-defined decision rules. As controls, healthy workers of similar socio-economic background, without memory problems and with no known exposure to organic solvents, were included in the study. Comparing patients and controls, higher frequencies of the variant *5B allele of the CYP2E1 gene (OR: 5.8; 95% CI: 1.8-18.8) and of the variant GSTP1*C allele (OR: 0.40; 95% CI: 0.17-0.94) were found. Homozygous carriers of the exon 4 EPHX1 Arg139 variant allele had a lower risk (OR:0.25; 95% CI: 0.06-1.13).

The present study indicates that genetic polymorphism of CYP2E1, EPHX1 and GSTP1 modify the risk of developing CSE.

Association of CYP1A1, GSTM1 and GSTT1 gene polymorphisms with risk of non-small cell lung cancer in Andhra Pradesh region of South India

BACKGROUND

Lung cancer is one of the most preventable causes of death globally both in developed and developing countries. Although it is well established that smokers develop lung cancer, there are some smokers who are free from the disease risk. The predisposition to lung cancer is attributed to genetic polymorphisms in xenobiotic metabolizing genes. Reports on assessment of xenobiotic metabolizing genes like Cytochrome P 450 1A1 (CYP1A1), Glutathione -S -transferase M1 (GSTM1) and T1 (GSTT1) polymorphisms from India are meagre, and reports from Andhra Pradesh are lacking.

METHODS AND RESULTS

Assessment of polymorphisms in CYP1A1, GSTM1 and GSTT1 in NSCLC patients and healthy individuals specific to population of Andhra Pradesh, a South Indian state was attempted by multiplex PCR and RFLP, and this is the first study which tried to correlate oxidative stress with the polymorphisms in xenobiotic metabolizing genes. Results showed that CYP1A1 m1 'CC' genotype was significantly associated with lung cancer susceptibility with a 2.3-fold risk, CYP1A1 m2 'AG' gene polymorphisms with 8.8-fold risk and GSTT1 (-/-) genotype demonstrated a twofold risk of disease susceptibility.

CONCLUSIONS

A combined role of genetic polymorphisms and smoking status can be attributed for the cause of lung cancer. Further, the association between oxidative stress and genetic polymorphisms showed a correlation between GSTT1 and super oxide dismutase activity; CYP1A1 m1, m2 and GSTT1 with glutathione peroxidase activity; CYP1A1 m1 and GSTM1 with melondialdehyde levels; and CYP1A1 m1 and GSTT1 with 8-oxo-7,8-dihydro-2'-deoxyguanosine. A higher risk of lung cancer seems to be associated with combined gene polymorphisms of phase I and phase II enzymes than that ascribed to single gene polymorphism.

Association of the p53 or GSTM1 polymorphism with the risk of nasopharyngeal carcinoma: A meta-analysis

p53 and glutathione S-transferase M1 (GSTM1) are the most popular suppressor genes. Several previous studies demonstrated positive associations of these gene polymorphisms with numerous cancer types, including hepatocellular cancer, while the association between p53/GSTM1 polymorphisms and the nasopharyngeal carcinoma (NPC) risk was inconsistent and underpowered. However, no studies investigating the combinational effect of these two genes on NPC risk were performed. To confirm the effects of p53 and GSTM1 polymorphisms on the risk of NPC, a meta-analysis of all the available previous studies associating p53 and GSTM1 with the risk of NPC was performed. A comprehensive search of PubMed, Web of Science and SD database until November 2014 was performed to identify the relevant studies. The data were extracted by two independent authors and pooled odds ratio (OR) with 95% confidence interval (CI) was calculated. Meta-regression and subgroup analyses were performed to identify the source of heterogeneity. Finally, five studies with 1,419 cases and 1,707 controls were included for the p53 polymorphism and three studies with 837 cases and 1,299 controls were included for the GSTM1 polymorphism. Regarding p53, a significantly increased NPC risk was observed in the overall population (C vs. G, OR, 1.245; 95% CI, 1.045-1.483; P=0.014; additive models: CC vs. GG, OR, 1.579; 95% CI, 1.100-2.265; P=0.013 and CG vs. GG, OR, 1.230; 95% CI, 1.039-1.456; P=0.016; dominant model, OR, 1.321; 95% CI, 1.127-1.549; P=0.001; recessive model, OR, 1.429; 95% CI, 1.017-2.009; P=0.040). Concerning GSTM1, a significantly increased NPC risk was observed in the overall population (null versus non-null, OR, 1.282; 95% CI, 1.075-1.530; P=0.006). In the subgroup analyses stratified by the source of controls, a significant association of p53 with NPC risk was also demonstrated, while no association with GSTM1 was observed. Therefore, the p53 G72C polymorphism may have a susceptible role in the carcinogenesis of NPC, while genetic deletion of GSTM1 may contribute to increased susceptibility to NPC. Further large and well-designed studies are required to confirm this association.

Genetic polymorphisms in GSTM1, GSTT1 and GSTP1 genes and risk of lung cancer in a North Indian population

BACKGROUND

A number of studies done so far in different populations have shown that polymorphisms within the GST genes play an important role in determining individual susceptibility to lung cancer; however, data obtained so far have been contradictory within the same or different populations. Few studies have focused on the combinatorial effect of the GST genes on susceptibility to lung cancer and also for different histological subtypes. Our aim is to investigate the roles of GSTM1, GSTT1, and GSTP1 polymorphisms as genetic modifiers of risk for lung cancer and histological subtypes using a larger sample size in a North Indian population.

METHODS

In total 540 subjects (270 lung cancer cases and 270 controls) were evaluated for the GST polymorphism. Genotyping for the GSTM1, GSTT1 and GSTP1 gene was done by using a multiplex PCR and PCR-RFLP method.

RESULTS

GSTM1 null genotype was found to be associated with lung cancer (OR=1.65, 95%CI: 116-2.3, P=0.005) and this risk was higher in cases of adenocarcinoma (ADCC). GSTT1 and GSTP1 did not show any significant association with lung cancer; however, when stratified for histological subtypes a significant association was observed for ADCC and small-cell lung cancer (SCLC) for both GSTT1 null and variant GSTP1 genotypes. The combined 'at risk' genotypes of null GSTM1 and GSTT1 genes were found to be associated with lung cancer risk, and this risk was higher in cases of ADCC (OR=4.09, 95%CI: 110-10.2, P=0.002). There is a twofold increased risk for lung cancer with the null GSTM1 and wild-type GSTP1 genotypes (P=0.0004); similarly, a fourfold increased risk was observed with the null GSTT1 and wild-type GSTP1 genotypes (P=0.0001).

CONCLUSIONS

The deficient GST genotypes seem thus to be important risk modifiers for lung cancer and related histological subtypes, especially in combination.

Glutathione S-Transferase Gene Polymorphisms: Modulator of Genetic Damage in Gasoline Pump Workers

This study investigated genetic damage in gasoline pump workers using the cytokinesis blocked micronucleus (CBMN) assay. Blood and urine samples were collected from 50 gasoline pump workers and 50 control participants matched with respect to age and other confounding factors except for exposure to benzene through gasoline vapors. To determine the benzene exposure, phenol was analyzed in urinary samples of exposed and control participants. Urinary mean phenol level was found to be significantly high (P < 0.05) in exposed workers. The CBMN frequency was found to be significantly higher in gasoline pump workers (6.70 ± 1.78) when compared to control individuals (2.20 ± 0.63; P < 0.05). We also investigated influence of polymorphisms of GSTM1, GSTT1, and GSTP1 genes on CBMN frequency. The individuals having GSTM1 and GSTT1 null genotypes had significantly higher frequency of CBMN (P < 0.05). Our study indicates that chronic and long-term exposure of gasoline vapors can increase genotoxic risk in gasoline pump workers.

Association Between the CYP1B1 Polymorphisms and Lung Cancer Risk: A Meta-Analysis

The previously published data on the association between the cytochrome P450 1B1 Leu432Val, Asn453Ser, and Ala119Ser polymorphisms and lung cancer risk have remained controversial. Hence, we performed a meta-analysis to investigate the association between cytochrome P450 1B1 Leu432Val, Asn453Ser, and Ala119Ser polymorphisms and lung cancer risk under different inheritance models. A total of 22 studies were identified, including 2881 cases and 3653 controls for Leu432Val polymorphism (from 13 studies), 3009 cases and 3887 controls for Asn453Ser polymorphism (from 5 studies), and 1301 cases and 2045 controls for Ala119Ser polymorphism (from 4 studies). Overall, significant association was observed between cytochrome P450 1B1 Leu432Val polymorphism and lung cancer risk (dominant model: odds ratio = 1.29, 95% confidence interval = 1.08-1.53; recessive model: odds ratio = 1.21, 95% confidence interval = 1.05-1.39; additive model: odds ratio = 1.43, 95% confidence interval = 1.21-1.69) when all the eligible studies were pooled into the meta-analysis. In the further stratified and sensitivity analyses, significantly increased lung cancer risk was also observed in caucasians and smokers. No significant association was observed between cytochrome P450 1B1Asn453Ser and Ala119Ser polymorphisms and lung cancer risk in overall analysis. In summary, this meta-analysis suggests that cytochrome P450 1B1Leu432Val polymorphism is associated with increased lung cancer risk in caucasians and smokers.

Glutathione-S-transferase (GSTM1, GSTT1) null phenotypes and risk of lung cancer in a Korean population

PURPOSE

The aim of this study was to evaluate any association of GSTM1 and GSTT1 null genotypes with the risk of lung cancer in a South Korean population.

METHODS

We conducted a large-scale, population-based case-control study including 3,933 lung cancer cases and 1,699 controls. Genotypes of GSTM1 and GSTT1 were determined using real-time polymerase chain reaction.

RESULTS

In logistic regression analysis adjusted for age and smoking, we did not find any association between GSTM1 or GSTT1 and LC risk in women. However, in men, the GSTM1 and GSTTI null genotypes were borderline associated with risk (OR=1.18, 95% CI=0.99-1.41 for GSTM1, OR=1.18, 95% CI=0.99-1.41 for GSTT1), and combined GSTM1 and GSTT1 null genotypes conferred an increased risk for LC in men (OR=1.39, 95% CI=1.08-1.78). The OR for the GSTT1 null genotype was greater in subjects aged 55 years old or younger (OR=1.45, 95% CI=1.09-1.92 for men; OR=1.36, 95% CI=0.97-1.90 for women), than in those over age 55 (OR=1.03, 95% CI=0.83-1.27 for men; OR=0.86, 95% CI=0.66-1.12 for women) in both genders (p for interaction <0.05).

CONCLUSIONS

In the Korean population, the GSTM1 and GSTT1 null genotypes are risk factors for LC in men; the GSTT1 null genotype has a more prominent effect on LC risk in younger people (age 55 years and under) than in older individuals.

Genetic polymorphisms in glutathione-S-transferases are associated with anxiety and mood disorders in nicotine dependence

Background

Nicotine dependence is associated with an increased risk of mood and anxiety disorders and suicide. The primary hypothesis of this study was to identify whether the polymorphisms of two glutathione-S-transferase enzymes (GSTM1 and GSTT1 genes) predict an increased risk of mood and anxiety disorders in smokers with nicotine dependence.

Materials and methods

Smokers were recruited at the Centre of Treatment for Smokers. The instruments were a sociodemographic questionnaire, Fagerström Test for Nicotine Dependence, diagnoses of mood disorder and nicotine dependence according to DSM-IV (SCID-IV), and the Alcohol, Smoking and Substance Involvement Screening Test. Anxiety disorder was assessed based on the treatment report. Laboratory assessment included glutathione-S-transferases M1 (GSTM1) and T1 (GSTT1), which were detected by a multiplex-PCR protocol.

Results

Compared with individuals who had both GSTM1 and GSTT1 genes, a higher frequency of at least one deletion of the GSTM1 and GSTT1 genes was identified in anxious smokers [odds ratio (OR)=2.21, 95% confidence interval (CI)=1.05–4.65, P=0.034], but there was no association with bipolar and unipolar depression (P=0.943). Compared with nonanxious smokers, anxious smokers had a greater risk for mood disorders (OR=4.67; 95% CI=2.24–9.92, P<0.001), lung disease (OR=6.78, 95% CI=1.95–23.58, P<0.003), and suicide attempts (OR=17.01, 95% CI=2.23–129.91, P<0.006).

Conclusion

This study suggests that at least one deletion of the GSTM1 and GSTT1 genes represents a risk factor for anxious smokers. These two genes may modify the capacity for the detoxification potential against oxidative stress.

Association of glutathione S-transferase P1 gene polymorphism with the risk of small-cell carcinoma of lung cancer

The conclusions of the published reports on the relationship between glutathione S-transferase P1 (GSTP1) gene polymorphism and the risk of small-cell carcinoma of lung cancer are still debated. GSTP1 is one of the important mutant sites reported at present. This meta-analysis was performed to evaluate the association between GSTP1 and the risk of small-cell carcinoma of lung cancer. The association investigations were identified from PubMed and Cochrane Library, and eligible studies were included and synthesized using meta-analysis method. Ten reports were included into this meta-analysis for the association of GSTP1 A/G gene polymorphism and small-cell carcinoma of lung cancer. The G allele and GG genotype were not associated with the susceptibility of risk of small-cell carcinoma in overall populations, East-Asians and Turkish population. However, there was an association between GG genotype with the risk of small-cell carcinoma in Caucasians. In conclusion, GG genotype was associated with the risk of small-cell carcinoma in Caucasian patients with lung cancer. However, GSTP1 A/G gene polymorphism is not associated with the susceptibility of small-cell carcinoma in overall populations, East-Asians and Turkish population.

HapMap-based study on the association between MPO and GSTP1 gene polymorphisms and lung cancer susceptibility in Chinese Han population

AIM

Myeloperoxidase (MPO) and glutathione S-transferase pi 1 (GSTP1) are important carcinogen-metabolizing enzymes. The aim of this study was to investigate the association between the common polymorphisms of MPO and GSTP1 genes and lung cancer risk in Chinese Han population.

METHODS

A total of 266 subjects with lung cancer and 307 controls without personal history of the disease were recruited in this case control study. The tagSNPs approach was used to assess the common polymorphisms of MOP and GSTP1 genes and lung cancer risk according to the disequilibrium information from the HapMap project. The tagSNP rs7208693 was selected as the polymorphism site for MPO, while the haplotype-tagging SNPs rs1695, rs4891, rs762803 and rs749174 were selected as the polymorphism sites for GSTP1. The gene polymorphisms were confirmed using real-time PCR, cloning and sequencing.

RESULTS

The four GSTP1 haplotype-tagging SNPs rs1695, rs4891, rs762803 and rs749174, but not the MPO tagSNP rs7208693, exhibited an association with lung cancer susceptibility in smokers in the overall population and in the studied subgroups. When Phase 2 software was used to reconstruct the haplotype for GSTP1, the haplotype CACA (rs749174+rs1695 + rs762803+rs4891) exhibited an increased risk of lung cancer among smokers (adjust odds ratio 1.53; 95%CI 1.04-2.25, P=0.033). Furthermore, diplotype analyses demonstrated that the significant association between the risk haplotype and lung cancer. The risk haplotypes co-segregated with one or more biologically functional polymorphisms and corresponded to a recessive inheritance model.

CONCLUSION

The common polymorphisms of the GSTP1 gene may be the candidates for SNP markers for lung cancer susceptibility in Chinese Han population.

GSTP1 Ile105Val polymorphism is associated with lung cancer risk among Asian population and smokers: an updated meta-analysis

Many studies have examined the association between the GSTP1 Ile105Val (rs 1695) gene polymorphism and lung cancer risk in various populations, but their results have been inconsistent. To assess this relationship more precisely, a meta-analysis was performed. The PubMed and CNKI database was searched for case-control studies published up to July 2012. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. Ultimately, 42 studies, comprising 12,304 lung cancer cases and 15,729 controls were included. Overall, for G allele carriers (GA + GG) versus homozygote AA, the pooled OR was 1.05 (95% CI 0.99-1.10 P = 0.092 for heterogeneity), for GG versus AA the pooled OR was 1.04 (95% CI 0.96-1.12 P = 0.084 for heterogeneity). In the stratified analysis by ethnicity, gender, histological types of lung cancer and smoking status, a significant association was found in Asians and smokers, not in Caucasian or mixed population, Male, Female population, lung AC, SCC, SCLC or non-smokers. Publication bias was found by using the funnel plot and Egger's test. Overall, there is no evidence showing a significant correlation between GSTP1 Ile105Val gene polymorphism and lung cancer risk in overall population, however stratified analysis by ethnicity, histology, gender and smoking status, it correlate with increased lung cancer susceptibility among Asians and smokers.

Association between glutathione S-transferase T1 null genotype and risk of lung cancer: a meta-analysis of 55 studies

The relationship between glutathione S-transferase T1 (GSTT1) gene polymorphism and the risk of lung cancer from the published reports are still conflicting. This study was conducted to evaluate the relationship between GSTT1 polymorphism and the risk of lung cancer. A comprehensive research was conducted through the databases, and 55 studies were recruited into this meta-analysis for the association of null genotype of GSTT1 with lung cancer susceptibility, consisting of 15,140 patients with lung cancer and 16,662 controls. There was a significant association between GSTT1 null genotype and lung cancer risk in the overall populations (OR = 1.138, 95% CI = 1.032-1.255, P heterogeneity = 0.000, P = 0.009). Furthermore, GSTT1 null genotype was associated with the lung cancer risk in Asians (OR = 1.469, 95% CI = 1.228-1.757, P heterogeneity = 0.000, P = 0.000). However, GSTT1 null genotype was not associated with the risk of lung cancer in Caucasians and Africans. In conclusion, GSTT1 null genotype is associated with the lung cancer in overall populations and in Asians.

A meta-analysis of the relationship between glutathione S-transferase T1 null/presence gene polymorphism and the risk of lung cancer including 31802 subjects

The relationship between glutathione S-transferase T1 (GSTT1) null/presence gene polymorphism and the risk of lung cancer from the published reports are still conflicting. This study was conducted to evaluate the relationship between GSTT1 null/presence gene polymorphism and the risk of lung cancer using meta-analysis method. The association studies were identified from PubMed, and Cochrane Library on July 1, 2012, and eligible investigations were included and synthesized using meta-analysis method. 51 reports were recruited into this meta-analysis for the association of null genotype of GSTT1 with lung cancer susceptibility, consisting of 15,140 patients with lung cancer and 16,662 controls. There was a marked association between GSTT1 null genotype and lung cancer risk in overall populations (OR = 1.15, 95 % CI 1.04-1.27, P = 0.007). Furthermore, GSTT1 null genotype was associated with the lung cancer risk in Asians (OR = 1.47, 95 % CI 1.23-1.76, P < 0.0001). However, GSTT1 null genotype was not associated with the risk of lung cancer in Caucasians, Brazilian population and Africans. In conclusion, GSTT1 null genotype is associated with the lung cancer in overall populations and in Asians.

Birth weight of Korean infants is affected by the interaction of maternal iron intake and GSTM1 polymorphism

Excessive iron consumption during pregnancy can lead to increased oxidative stress in the maternal body, which may result in adverse pregnancy outcomes. Glutathione S-transferases (GSTs) originate from a superfamily of detoxifying enzymes that play a role in reducing xenobiotic compounds and oxidative stress. The aim of this study was to determine the relationship among GST gene expression, maternal iron intake during pregnancy, and neonatal birth weight. The study participants were 1087 Korean gravidas and their newborns recruited for the Mothers and Children's Environmental Health study between 2006 and 2010. A 24-h dietary recall interview was conducted to estimate iron intake; additional intake through nutritional supplements was thoroughly investigated. Deletion polymorphisms of GSTM1 and GSTT1 were genotyped using PCR. Dietary iron consumption during pregnancy was positively associated with birth weight in pregnant women who were GSTM1-present after adjustment for the following covariates: maternal age, prepregnancy BMI, mother's education level, log-transformed urinary cotinine level, infant gender, gestational age at term, log-transformed energy intake, parity, and the use of folic acid supplements (P < 0.05). There were interactions between the GSTM1 genotype and iron intakes from animal foods (P < 0.05), diet (P < 0.05), and diet with supplements (P < 0.05). No relationship was found between maternal iron intake and birth weight for the GSTT1 polymorphism. This study demonstrates that increased iron consumption during pregnancy may improve infant birth weight for mothers who are GSTM1-present, but it might not be beneficial for mothers with the GSTM1-null genotype.

Association of glutathione S-transferase P1 gene polymorphism with the histological types of lung cancer: a meta-analysis

The conclusions of the published reports on the relationship between glutathione S-transferase P1 (GSTP1) A/G gene polymorphism and the histological types of lung cancer are still debated. GSTP1 is one of the important mutant sites reported at present. This meta-analysis was performed to evaluate the association between GSTP1 and histological types of lung cancer. The association investigations were identified from PubMed and Cochrane Library, and eligible studies were included and synthesized using meta-analysis method. Seventeen reports were included into this meta-analysis for the association of GSTP1 A/G gene polymorphism and histological types of lung cancer. The G allele and GG genotype were not associated with the susceptibility of risk of squamous cell carcinomas, adenocarcinomas, small cell carcinoma, non-small cell carcinoma or large cell carcinoma. However, in the sub-group analysis, there was an association between G allele/GG genotype with the risk of squamous cell carcinomas in East-Asians and GG genotype was associated with the risk of small cell carcinoma in Caucasians. In conclusion, GSTP1 A/G gene polymorphism is not associated with the susceptibility of squamous cell carcinomas, adenocarcinomas, small cell carcinoma, non-small cell carcinoma or large cell carcinoma.

Association of glutathione S-transferase P1 gene polymorphism with the susceptibility of lung cancer

The conclusions of the published reports on the relationship between glutathione S-transferase P1 (GSTP1) gene polymorphism and the risk of lung cancer are still debated. GSTP1 is one of the important mutant sites reported at present. This meta-analysis was performed to evaluate the association between GSTP1 and the risk of lung cancer. The association investigations were identified from PubMed and Cochrane Library, and eligible studies were included and synthesized using meta-analysis method. Forty-four reports were included into this meta-analysis for the association of GSTP1 A/G gene polymorphism and lung cancer susceptibility, consisting of 12,363 patients with lung cancer and 13,948 controls. The association between GSTPI G allele and lung cancer risk was found in this meta-analysis (OR 1.08, 95 % CI 1.02-1.15, P = 0.01). However, the GG genotype and AA genotype were not associated with the susceptibility of lung cancer. Furthermore, there was no association between GSTP1 A/G gene polymorphism and the risk of lung cancer in Caucasians, and East-Asians. In conclusion, GSTP1 G allele is associated with the lung cancer susceptibility. However, more studies on the relationship between GSTP1 A/G gene polymorphism and the risk of lung cancer should be performed in the future.

Genetic polymorphisms in CYP1A1, GSTM1, GSTP1 and GSTT1 metabolic genes and risk of lung cancer in Asturias

BACKGROUND

Metabolic genes have been associated with the function of metabolizing and detoxifying environmental carcinogens. Polymorphisms present in these genes could lead to changes in their metabolizing and detoxifying ability and thus may contribute to individual susceptibility to different types of cancer. We investigated if the individual and/or combined modifying effects of the CYP1A1 MspI T6235C, GSTM1 present/null, GSTT1 present/null and GSTP1 Ile105Val polymorphisms are related to the risk of developing lung cancer in relation to tobacco consumption and occupation in Asturias, Northern Spain.

METHODS

A hospital-based case-control study (CAPUA Study) was designed including 789 lung cancer patients and 789 control subjects matched in ethnicity, age, sex, and hospital. Genotypes were determined by PCR or PCR-RFLP. Individual and combination effects were analysed using an unconditional logistic regression adjusting for age, pack-years, family history of any cancer and occupation.

RESULTS

No statistically significant main effects were observed for the carcinogen metabolism genes in relation to lung cancer risk. In addition, the analysis did not reveal any significant gene-gene, gene-tobacco smoking or gene-occupational exposure interactions relative to lung cancer susceptibility. Lastly, no significant gene-gene combination effects were observed.

CONCLUSIONS

These results suggest that genetic polymorphisms in the CYP1A1, GSTM1, GSTT1 and GSTP1 metabolic genes were not significantly associated with lung cancer risk in the current study. The results of the analysis of gene-gene interactions of CYP1A1 MspI T6235C, GSTM1 present/null, GSTT1 present/null and GSTP1 Ile105Val polymorphisms in lung cancer risk indicate that these genes do not interact in lung cancer development.

Combined effects of GSTO1 and SULT1A1 polymorphisms and cigarette smoking on urothelial carcinoma risk in a Taiwanese population

BACKGROUND/PURPOSE

Cigarette smoking is the main risk factor for urothelial carcinoma of the bladder (UCB). Glutathione S-transferase omega 1 (GSTO1) and sulfotransferase 1A1 (SULT1A1) have been reported to be associated with the metabolism of polycyclic aromatic hydrocarbons (PAHs) and aromatic amines. The aim of the present study was to investigate the combined effects of polymorphisms in GSTO1 and SULT1A1 genes and cigarette smoking on UCB risk in a Taiwanese population.

METHODS

A total of 300 patients with histopathologically confirmed UCB and 233 cancer-free controls were recruited from the Department of Urology of Tung's Taichung Metro Harbor Hospital and Taipei Medical University Hospital. A comprehensive interview was conducted to collect personal information, including demographic characteristics and cigarette smoking status. A multivariate-adjusted logistic regression was performed to estimate the risk of UCB.

RESULTS

A significantly increased risk of UCB was observed in ever smokers [odds ratio (OR) = 2.3]. The Ala/Ala genotype of the GSTO1 gene and the Arg/Arg genotype of the SULT1A1 gene were associated with a significantly increased risk of UCB, with ORs of 1.8 [95% confidence interval (CI) = 1.2-2.6] and 2.1 (95% CI = 1.6-4.5), respectively. Significantly increased UCB risks were found in heavy smokers with the Ala/Ala genotype of the GSTO1 gene (OR = 4.2) and the Arg/Arg genotype of the SULT1A1 gene (OR = 6.8). Furthermore, a significant synergistic effect in an additive model (OR = 3.5) between the GSTO1 Ala/Ala genotype and the SULT1A1 Arg/Arg genotype on UCB risk was observed.

CONCLUSION

The present study provided epidemiological evidence for a significantly increased risk of UCB in ever smokers with the Ala/Ala genotype of the GSTO1 gene and the Arg/Arg genotype of the SULT1A1 gene.

Relevance of GSTM1, GSTT1, and GSTP1 gene polymorphisms to gastric cancer susceptibility and phenotype

Human glutathione S-transferases (GSTs) are phase II metabolizing enzymes that play a key role in protecting against cancer by detoxifying numerous potentially cytotoxic/genotoxic compounds. The genes encoding the human GST isoenzymes GSTM(mu)1, GSTT(theta)1 and GSTP(pi)1 harbour polymorphisms, which have been considered important modifiers of the individual risk for environmentally induced cancers such as gastric cancer (GC). However, results are inconsistent among studies from different geographic areas and ethnic groups. Our goal was to perform a nationwide, case-control study in Spain to evaluate the relevance of several functional GST gene polymorphisms and environmental factors to GC risk and phenotype. DNA from 557 GC patients and 557 sex- and age-matched healthy controls (HC) was typed for two deletions in the GSTM1 and GSTT1 genes and two SNPs in the GSTP1 gene (rs1695 and rs1138272) using polymerase chain reaction-restriction fragment length polymorphism methods. Logistic regression analysis identified Helicobacter pylori infection with CagA strains [odds ratio (OR): 2.36; 95% confidence interval (CI): 1.78-3.15], smoking habit (OR: 2.10; 95% CI: 1.48-2.97) and family history of GC (OR: 3.2; 95% CI: 2.02-5.16) as independent risk factors for GC. No differences in the frequencies of GSTM1 or GSTT1 null genotypes were observed between cases and controls (GSTM1: 50.8% vs. 48%; GSTT1: 21.5% vs. 21%). Moreover, simultaneous carriage of both, the GSTM1 and the GSTT1 null genotypes, was almost identical in both groups (10.7% in GC vs. 10.6% in HC). In addition, no significant differences in GSTP1 Ile105Val (rs1695) and GSTP1 Val114Ala (rs1138272) genotype distribution were observed between GC patients and controls. Subgroup analysis for age, gender, Helicobacter pylori status, smoking habits, family history of GC, anatomic location and histological subtype revealed no significant association between GST variants and GC risk. Our results show that the GST polymorphisms evaluated in this study are not relevant when determining the individual susceptibility to GC or phenotype in a South-European population.

CYP2E1, GSTM1 and GSTT1 genetic polymorphisms and susceptibility to antituberculosis drug-induced hepatotoxicity: a nested case-control study

WHAT IS KNOWN AND OBJECTIVE

The pathogenic mechanism of antituberculosis drug-induced hepatotoxicity (ATDH) is thought to involve drug-metabolizing enzymes including N-acetyl transferase2 (NAT2), cytochrome P4502E1 (CYP2E1) and glutathione S-transferase (GST) M1, T1. The associations between genetic polymorphisms of those genes and ATDH have been reported but with inconsistent results. Moreover, most studies were hospital-based retrospective studies and not prospective. We aimed to investigate possible associations of CYP2E1, GSTM1 and GSTT1 genetic polymorphisms with ATDH using a more robust case-control study nested in a population-based prospective antituberculosis treatment cohort.

METHODS

A total of 4304 patients with smear-positive tuberculosis (TB) who received standard short-course chemotherapy were monitored for 6-9 months. Incidence density sampling method was adopted to select controls and 4 : 1 matched with each ATDH cases by age (± 5 years), sex, treatment history, disease severity and drug dosage. The CYP2E1, GSTM1 and GSTT1 polymorphisms were genotyped using PCR-RFLP and multiplex PCR methods. Conditional logistic regression model was used to calculate odds ratio (OR) and 95% confidence interval (CI), as well as corresponding P-values.

RESULTS AND DISCUSSION

A total of 89 ATDH cases and 356 controls were included in this study. There was no statistically significant association between CYP2E1 RsaI c1/c1 genotype or DraI C/C genotype and ATDH (OR = 0·99, 95% CI:0·62-1·59; OR = 1·13, 95% CI: 0·40-3·20, respectively) compared with CYP2E1 RsaI c1/c2 or c2/c2 genotypes or DraI D/D genotype, or between GSTM1/GSTT1 null genotypes and ATDH (OR = 1·22, 95% CI: 0·76-1·96; OR = 0·96, 95% CI: 0·60-1·52, respectively) compared with non-null genotypes.

WHAT IS NEW AND CONCLUSION

This is the first study of the involvement of CYP2E1, GSTM1 and GSTT1 genetic polymorphisms in ATDH using a nested case-control population-based prospective cohort design. We could not confirm positive associations of genetic polymorphisms of CYP2E1 RsaI, CYP2E1 DraI, GSTM1 null and GSTT1 null with ATDH reported by various groups, in our Chinese TB population.

Polymorphisms of glutathione S-transferases M1, T1, P1 and A1 genes in the Tunisian population: an intra and interethnic comparative approach

Genetic polymorphisms in glutathione S-transferases (GSTs) genes might influence the detoxification activities of the enzymes predisposing individuals to cancer risk. Owing to the presence of these genetic variants, inter-individual and ethnic differences in GSTs detoxification capacity have been observed in various populations. Therefore, the present study was performed to determine the prevalence GSTM1 0/0, GSTT1 0/0, GSTP1 Ile(105)Val, and GSTA1 A/B polymorphisms in 154 healthy individuals from South Tunisia, and to compare them with those observed in North and Centre Tunisian populations and other ethnic groups. GSTM1 and GSTT1 polymorphisms were analyzed by a Multiplex-PCR approach, whereas GSTP1 and GSTA1 polymorphisms were examined by PCR-RFLP. The frequencies of GSTM10/0 and GSTT1 0/0 genotypes were 53.9% and 27.9%, respectively. The genotype distribution of GSTP1 was 47.4% (Ile/Ile), 40.9% (Ile/Val), and 11.7% (Val/Val). For GSTA1, the genotype distribution was 24.7% (A/A), 53.9% (A/B), and 21.4% (B/B). The combined genotypes distribution of GSTM1, GSTT1, GSTP1 and GSTA1 polymorphisms showed that thirty one of the 36 possible genotypes were present in our population; eight of them have a frequency greater than 5%. To the best of our knowledge, this is the first report of GSTs polymorphisms in South Tunisian population. Our findings demonstrate the impact of ethnicity and reveal a characteristic pattern for Tunisian population. The molecular studies in these enzymes provide basis for further epidemiological investigations in the population where these functional polymorphisms alter therapeutic response and act as susceptibility markers for various clinical conditions.

GSTM1, GSTT1 and GSTP1 gene polymorphism in polymorphous light eruption

BACKGROUND

Polymorphous light eruption (PLE) is the most common chronic and idiopathic photodermatosis. PLE is assumed to represent an immunological hypersensitivity reaction to a radiation-induced cutaneous antigen involving reactive oxygen species (ROS) on the basis of a genetic predisposition. Among others, cellular protection against ROS is provided by glutathione S-transferases (GSTs). Different variants of the GST enzymes may influence the activity and efficiency of detoxification and biotransformation of unknown UV-induced skin-antigens and other factors that may play an important role in the pathogenesis of PLE.

METHODS

In this study the relationship between isoenzymes of the GST genes GSTM1, GSTT1 and GSTP1 and possible protective or predisposing effects on PLE was examined in 29 patients and 144 controls. Diagnosis of PLE was based on the presence of characteristic clinical features.

RESULTS

No association between the functional polymorphisms of the GST gene family and PLE was found. Prevalence of certain GST isoenzymes or polymorphisms in patients with PLE did not differ from healthy controls.

CONCLUSION

Our data do not support prevalence of GST isoenzymes or polymorphisms as a protective effect against PLE. Especially a higher carrier frequency of GSTP1 Val(105) as a protective factor against PLE which has been published before could not be proved. The GST genotypes GSTM1, GSTT1 and GSTP1 (including SNPs) seem to have no relevant association with PLE.

Association between GSTM1, GSTT1, and GSTP1 polymorphisms and lung cancer risk in a Turkish population

Several studies focused on investigating genetic polymorphisms in order to estimate genetic contribution to lung cancer often showed conflicting results. In this study, we investigated the role of GSTM1, GSTT1, GSTP1 exon 5 and exon 6 polymorphisms on developing lung cancer and histological subtypes in 213 lung cancer patients and 231 controls. GSTM1 null, GSTT1 null, and GSTP1 exon 5 variant genotypes did not show a significant risk for developing lung cancer overall. Significant association was noted between GSTP1 exon 6 variant genotypes and overall lung cancer risk (OR 2.17, 95% CI 1.25-3.78; P = 0.006). These results show that GSTP1 exon 6 polymorphism might be an important factor in determining lung cancer susceptibility in a Turkish population.

Association of a deletion of GSTT2B with an altered risk of oesophageal squamous cell carcinoma in a South African population: a case-control study

Background

Polymorphisms in the Glutathione S-transferase genes are associated with altered risks in many cancers, but their role in oesophageal cancer is unclear. Recently a 37-kb deletion polymorphism of GSTT2B that reduces expression of GSTT2 has been described. We evaluated the influence of the GSTT1 and GSTT2B deletion polymorphisms, and the GSTP1 Ile105Val polymorphism (rs1695) on susceptibility to oesophageal squamous cell carcinoma (OSCC) in the Black and Mixed Ancestry populations of South Africa.

Methods and Results

The GSTT1, GSTT2B and GSTP1 variants were genotyped in 562 OSCC cases and 907 controls, and tested for association with OSCC and for interaction with smoking and alcohol consumption. Linkage disequilibrium (LD) between the deletions at GSTT1 and GSTT2B was determined, and the haplotypes tested for association with OSCC. Neither the GSTT1 deletion nor the GSTP1 Ile105Val polymorphism was associated with OSCC risk in the Black or Mixed Ancestry populations. The GSTT2B deletion was not associated with OSCC risk in the Black population, but was associated with reduced risk of OSCC in the Mixed Ancestry population (OR = 0.71; 95% CI 0.57–0.90, p = 0.004). Case-only analysis showed no interaction between the GST polymorphisms and smoking or alcohol consumption. LD between the neighboring GSTT1 and GSTT2B deletions was low in both populations (r²_Black = 0.04; r²_MxA = 0.07), thus these deletions should be assessed independently for effects on disease risk.

Conclusions

Although there was no association between the GSTT1 deletion polymorphism or the GSTP1 Ile105Val polymorphism with OSCC, our results suggest that the presence of the recently described GSTT2B deletion may have a protective effect on the risk of OSCC in the Mixed Ancestry South African population. This is the first report of the contribution of the GSTT2B deletion to cancer risk.

Lack of association between glutathione S-transferase T1 gene polymorphism and laryngeal cancer susceptibility: a meta-analysis based on 2,124 cases and 2,059 controls

Studies investigating the association between glutathione S-transferase T1 (GSTT1) gene polymorphism and laryngeal cancer susceptibility have reported conflicting results. The aim of the present study was to conduct a meta-analysis assessing the possible association of GSTT1 gene polymorphism with laryngeal cancer risk. The relevant studies were identified through a search of PubMed, Embase, ISI Web of Knowledge and Chinese National Knowledge Infrastructure until May 2011. Twelve studies were included in the present meta-analysis, which described a total of 2124 laryngeal cancer cases and 2059 controls. The overall odds ratio (OR) for GSTT1 null genotype was 1.40 (95% CI=0.90-2.16). When stratifying for race, the pooled ORs for GSTT1 null genotype were 1.07 (95% CI=0.81-1.41) in Caucasians and 5.63 (95% CI=1.00-31.83) in Asians. The pooled ORs for GSTT1 null genotype were 1.03 (95% CI=0.71-1.49) in population-based studies and 2.39 (95% CI=0.73-7.86) in hospital-based studies, stratifying for study design. This meta-analysis suggested that there was lack of association between GSTT1 gene polymorphism and laryngeal cancer risk. However, larger scale primary studies are still required to further evaluate the interaction of GSTT1 gene polymorphism with laryngeal cancer risk.

Population differences in major functional polymorphisms of pharmacokinetics/pharmacodynamics-related genes in Eastern Asians and Europeans: implications in the clinical trials for novel drug development

Drug lag, recently discussed extensively in Japan, can be divided into two phases: clinical development time and application review time. The former factor is still an important problem that might be improved by promoting multi-regional clinical trials and considering the results from other similar populations with Japanese, such as Koreans and Chinese. In this review, we compare the allelic or genotype frequencies of 30 relatively common functional alleles mainly between Eastern Asians and Europeans as well as among 3 major populations in Eastern Asian countries, Japan, Korea, and China, in 12 pharmacokinetics (PK)/pharmacodynamics (PD)-related genes; CYP2C9 (*2 and *3), CYP2C19 (*2, *3 and *17), 13 CYP2D6 haplotypes including *4, *5 and *10, CYP3A5 (*3), UGT1A1 (*28 and *6), NAT2 (*5, *6 and *7), GSTM1 and GSTT1 null genotypes, SLCO1B1 521T>C, ABCG2 421C>A, and HLA-A*31:01 and HLA-B*58:01. In this review, differences in allele frequencies (AFs) or genotype frequencies (GFs) less than 0.1 (in the cases of highest AF (GF) ≥0.1) or less than 0.05 (in the cases of lowest AF (GF) <0.1) were regarded as similar. Between Eastern Asians and Europeans, AFs (or GFs) are regarded as being different for many alleles such as CYP2C9 (*2), CYP2C19 (*2, *3 and *17), CYP2D6 (*4 and *10), CYP3A5 (*3), UGT1A1 (*28 and *6), NAT2 (*5*7), GSTT1 null and ABCG2 421C>A. Among the 3 Eastern Asian populations, however, only AFs of CYP2C19*3, CYP2D6*10, HLA-A*31:01 and HLA-B*58:01 are regarded as dissimilar. For CYP2C19*3, the total functional impact on CYP2C19 could be small if the frequencies of the two null alleles CYP2C19*2 and *3 are combined. Regarding CYP2D6*10, frequency difference over 0.1 is observed only between Japanese and Chinese (0.147). Although environmental factors should be considered for PK/PD differences, we could propose that among Japan, Korea, and China, genetic differences are very small for the analyzed common PK-related gene polymorphisms. On the other hand, AFs of the two HLA alleles important for cutaneous adverse drug reactions are diverse even among Eastern Asians and thus should be taken into account.

Assessment of cumulative evidence for the association between glutathione S-transferase polymorphisms and lung cancer: application of the Venice interim guidelines

OBJECTIVE

There is an overwhelming abundance of genetic association studies available in the literature, which can often be collectively difficult to interpret. To address this issue, the Venice interim guidelines were established for determining the credibility of the cumulative evidence. The objective of this report is to evaluate the literature on the association of common glutathione S-transferase (GST) variants (GSTM1 null, GSTT1 null and GSTP1 Ile105Val polymorphism) and lung cancer, and to assess the credibility of the associations using the newly proposed cumulative evidence guidelines.

METHODS

Information from the literature was enriched with an updated meta-analysis and a pooled analysis using data from the Genetic Susceptibility to Environmental Carcinogens database.

RESULTS

There was a significant association between GSTM1 null and lung cancer for the meta-analysis (meta odds ratio=1.17, 95% confidence interval: 1.10-1.25) and pooled analysis (adjusted odds ratio=1.10, 95% confidence interval: 1.04-1.16), although substantial heterogeneity was present. No overall association between lung cancer and GSTT1 null or GSTP1 Ile105Val was found. When the Venice criteria was applied, cumulative evidence for all associations were considered 'weak', with the exception of East Asian carriers of the G allele of GSTP1 Ile105Val, which was graded as 'moderate' evidence.

CONCLUSION

Despite the large amounts of studies, and several statistically significant summary estimates produced by meta-analyses, the application of the Venice criteria suggests extensive heterogeneity and susceptibility to bias for the studies on association of common genetic polymorphisms, such as with GST variants and lung cancer.

The expression of GST isoenzymes and p53 in non-small cell lung cancer

This study investigated the immunohistochemical staining characteristics of glutathione-S-transferase alpha, pi, mu, theta and p53 in non-small cell lung carcinoma and normal lung tissue from 50 patients. The relationships between expressions of the Glutathione-S-transferase isoenzymes and some clinicopathological features were also examined. Expression of glutathione-S-transferase pi, mu, alpha, theta and p53 was assessed by immunohistochemistry for primary lung carcinomas of 50 patients from the Sanitarium Education and Research Hospital, Ankara lung cancer collection. The relationships between expression of the glutathione-S-transferase isoenzymes, p53 in normal and tumor tissue by Student T test and the clinicopathological data were also examined by Spearman Rank tests. When the normal and tumor tissue of these cases were compared according to their staining intensity and percentage of positive staining, glutathione-S-transferase alpha, pi, mu, theta expressions in tumor cells was significantly higher than normal cells (p<0.05). There was no significant difference in the expression of p53 between normal and tumor cells (p>0.05). When the immunohistochemical results of glutathione-S-transferase isoenzymes and p53 were correlated with the clinical parameters, there were no significant associations between glutathione-S-transferases and p53 expressions and tumor stage, tumor grade and smoking status (p>0.05).

Distribution of glutathione S-transferase T1 and M1 genes polymorphisms in North East Indians: a potential report

BACKGROUND

Detoxifying glutathione S-transferase (GST) gene polymorphisms show variation in different ethnic populations. GST detoxifies and metabolizes carcinogens, including oxygen free radicals. GST polymorphisms have been associated with susceptibility to different diseases. In the current study, allelic polymorphisms of GSTM1 and GSTT1 were analyzed in three ethnic groups of North East (NE) India where a high prevalence of various cancers and other diseases such as hypertension, tuberculosis, and asthma have been reported.

METHODS

We compared the prevalence of GSTT1 and GSTM1 deletion genotypes, which were determined by multiplex polymerase chain reaction, in 422 voluntary, healthy NE Indians with those of other populations. The data was statistically analyzed.

RESULTS

The GSTT1-null genotype was found in 51%, 34.3%, and 15.7% of individuals (from Mizoram, Sikkim, and Assam regions of NE India, respectively), whereas the GSTM1-null genotype was found in 46.9%, 46%, and 35% of individuals from the same areas.

CONCLUSIONS

The NE Indians differ from the rest of the Indian population with reference to genotypic distribution of GST polymorphisms but the frequency was found to be similar to that which has been reported from China. This may explain the hypothesis of the common ancestral origin of both the NE Indians and the Chinese and a higher frequency of cancers such as gastric, esophageal, and oral cancers, which has been reported from these regions. This study establishes baseline frequency data for GST polymorphisms for future case control studies on the role these polymorphisms play with regard to diseases. The results presented here provide the first report on GST polymorphisms in the NE Indian population.

GSTM1, GSTT1, and GSTP1 polymorphism in north Indian population and its influence on the hydroquinone-induced in vitro genotoxicity

Glutathione S transferase (GST) gene polymorphism examined among north Indians and correlated with hydroquinone (HQ) genotoxicity to help in clinical prediction of susceptibility of HQ toxicity. Lymphocytes of individuals with/without GSTM1, GSTT1, and GSTP1 (ile/ile or val/val) were exposed to HQ (20, 40, or 80 microM) and examined chromosomal aberrations (CA) or cytokinesis-block micronucleus assays. Among north Indians the frequencies of GSTM1 (null), GSTT1 (null), and both null were found to be 41.1, 21.9, and 12.7%, whereas frequencies of GSTP1 with (ile/ile) or (ile/val), or (val/val) were 52, 42.1, or 5.9%, respectively. Individuals with null GSTM1, GSTT1, and GSTP1 (val/val) showed inhibition of mitotic index (MI) and significant (p < 0.01) induction of CA as compared to individuals with GSTM1, GSTT1, and GSTP1 (ile/ile). Micronucleus formation was found to be significant (p < 0.05 or 0.01) in both the genotypes. Results indicate that GSTM1, GSTT1 (null), and GSTP1 (val/val) are sensitive to HQ genotoxicity.

Glutathione S-transferases: an overview in cancer research

IMPORTANCE OF THE FIELD

The Glutathione S-transferases (GSTs) have advanced beyond the classic view of their role in metabolism and are encouraging scientists to assess new approaches to cancer risk characterization and chemotherapy resistance and are opening up exciting possibilities in drug discovery.

AREAS COVERED IN THIS REVIEW

In this review, the most recent knowledge about the impact of GST genetic polymorphisms in human's cancer susceptibility, ethnic differences in the effects of risk factors and the rise of the GSTs as important targets for drug development are presented. In this context, the ethnic distribution of GST alleles in different populations, which is an important concept that is being incorporated in epidemiologic studies of cancer risk and environmental exposure, was also evaluated. We present up-to-date information about the new generation of GST-activated cytotoxic prodrugs based on GST overexpression in tumor-acquired drug resistance and the newest results of clinical trials.

WHAT THE READER WILL GAIN

A critical approach of the major advances in research of GST, underlining the new advances of GST genes polymorphisms in cancer susceptibility and target for therapeutic intervention.

TAKE HOME MESSAGE

Although polygenic factors are involved in increased risk of cancer, the interindividual GST variability plays a central role in reduce cells exposure to carcinogens.

Interaction between GSTM1/GSTT1 polymorphism and blood mercury on birth weight

BACKGROUND

Mercury (Hg) is toxic to both the reproductive and nervous systems. In addition, glutathione S-transferases (GSTs), which conjugate glutathione to a variety of electrophilic compounds, are involved in the detoxification of Hg.

OBJECTIVE

In this study we examined the association between prenatal exposure to Hg and birth weight as well as the influence of GST polymorphisms.

METHODS

The total Hg concentration in maternal and cord blood was measured from 417 Korean women and newborns in the Mothers and Children's Environmental Health study from 2006 to 2008. Information on birth weight was collected from the patients' medical records. The genotyping of glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) polymorphisms was carried out using polymerase chain reaction. Regression analysis was performed to determine the association between the blood Hg concentration and birth weight in mothers with GSTM1 and GSTT1 polymorphisms.

RESULTS

The geometric mean levels of Hg in the maternal blood during late pregnancy and in cord blood were 3.30 microg/L and 5.53 microg/L, respectively. For mothers with the GSTT1 null genotype, elevated Hg levels in maternal blood during late pregnancy were associated with an increased risk of lower birth weight. For mothers with both GSTM1 and GSTT1 null genotype, both maternal and cord blood Hg levels were associated with lower birth weight.

CONCLUSIONS

This study suggests that the interactions of Hg with GSTM1 and GSTT1 polymorphisms play a role in reducing birth weight.