Glutathione S-transferase Mu 1 Polymorphisms Research Articles

Study on the association of Glutathione S-transferase Mu 1 (GSTM1) gene polymorphism with acute decompensated heart failure with reduced ejection fraction

The most frequent cause of hospitalization in adults over 65 in Western nations is acute decompensation of heart failure (ADHF). Due to the high death rate, it places a heavy load on healthcare systems as well as people. The present study’s objective was to ascertain the connection between polymorphisms in the Glutathione S-transferase Mu 1 (GSTM1) gene and heart-failure-reduced ejection fraction (HFrEF) patients. Sixty patients with a mean age of 25–94 were taken from both genders after the clinical diagnosis by a specialist to cases who were referred to the Ibn Al-Baitar Specialized Center for Cardiac Surgery and Ramadi Teaching Hospital, and thirty apparently healthy people were taken as a control. Blood and serum containing EDTA were drawn from sick and healthy people to extract DNA for multiplex PCR detection of the GSTM1 polymorphism. The GSTM1 genotype was found in 23 (38.33%) and the null gene in 37 (61.66%) of the 60 ADHF patients. Of 30 healthy people, 8 (26.66%) had the GSTM1 gene and 22 (73.33%) had the null gene. According to the present study, the etiology of acute decompensated heart failure (ADHF) and the antioxidant null gene (GSTM1) are related. The present study has been achieved to determine the relationship between the presence of the antioxidant gene (GSTM1) and the incidence of ADHF with reduced ejection fraction for research and therapeutic purposes, which opens new spaces in the treatment of the mentioned condition.

GSTM1 Deletion Compensated in mRNA Expression and 4T1 Viability After Editing Using CRISPR/Cas9 Single and Double gRNA

BACKGROUND: Glutathione S-transferase Mu-1 (GSTM1) is known to undergo polymorphism and plays role in drug metabolism including Paclitaxel (PTX), the first-line chemotherapy for breast cancer. However, the effect of GSTM1 polymorphism against chemotherapy in breast cancer is limited and unexplored. This study was conducted to explore the effects of single and double guide (gRNA) on the GSTM1 knocked out (KO) and its effect on the response of PTX in the 4T1 cell line.METHODS: The preparatory stage was done by culturing and electroporating 4T1 cells using Ribonucleoprotein of clustered regularly interspaced short palindromic repeats (CRISPR)/Caspase 9 (Cas9). KO validation was examined by quantitative reverse transcription polymerase chain reaction (qRT-PCR), Sanger sequencing, and ICE analysis. The 4T1 viability was examined by MTT Assay.RESULTS: The number of base pairs of GSTM1 after being engineered by single or double gRNA was 86 bases. The DNA quantity of GSTM1 engineered by gRNA was more than using double gRNAs. The mRNA expression of GSTM1 engineered by single gRNA was lower than using double gRNAs. IC50 values of PTX between wildtype and KO were not significantly different, in the range of 30 µM.CONCLUSION: The base-pair length of GSTM1 exon 4 that is knocked out with single and double gRNA have the same number of base pairs. The quantity of GSTM1 DNA and mRNA expression are contrary between single gRNA and double gRNA, and IC50 PTX values in the 4T1 cell line of the control group with single or double gRNA knocked out do not differ markedly. PTX efficiency as chemotherapy is not disturbed in the GSTM1 deletion genetic profile.KEYWORDS: GSTM1, gRNA, Paclitaxel, CRISPR, breast cancer

Air pollution associated acute respiratory inflammation and modification by GSTM1 and GSTT1 gene polymorphisms: a panel study of healthy undergraduates

Epidemiological evidence has linked air pollution with adverse respiratory outcomes, but the mechanisms underlying susceptibility to air pollution remain unclear. This study aimed to investigate the role of glutathione S-transferase (GST) polymorphism in the association between air pollution and lung function levels. A total of 75 healthy young volunteers aged 18–20 years old were recruited for six follow-up visits and examinations. Spirometry was conducted to obtain lung function parameters such as forced vital capacity (FVC), and forced expiratory volume in 1 s (FEV1). Nasal fluid concentrations of interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and 8-epi-prostaglandin F2α (8-epi-PGF2a) were measured using ELISA kits. Linear mixed-effect models were used to evaluate the association of air pollutants with respiratory outcomes. Additionally, polymorphisms of glutathione S-transferase mu 1 (GSTM1) and glutathione S-transferase theta 1 (GSTT1) were estimated to explore its role in the association between air pollutants and lung function. We found that short-term exposure to atmospheric particulates such as PM2.5 and PM10 can cause an increase in nasal biomarkers of inflammation, oxidative stress, and lung function, while air gaseous pollutant exposure is linked with decreased lung function, except for CO. Stratification analyses showed that an increase in nasal inflammatory cytokines caused by exposure to atmospheric particulates is more obvious in subjects with GSTM1-sufficient (GSTM1+) than GSTM1-null (GSTM1−), while elevated lung function levels due to air particles are more significant in subjects with the genotype of GSTM1− when compared to GSTM1+. As for air gaseous pollutants, decreased lung function levels caused by O3, SO2, and NO2 exposure is more manifest in subjects with the genotype of GSTM1− compared to GSTM1+. Taken together, short-term exposure to air pollutants is associated with alterations in nasal biomarkers and lung function levels in young healthy adults, and susceptible genotypes play an important mediation role in the association between exposure to air pollutants and inflammation, oxidative stress, and lung function levels.

Genetic Polymorphisms of GSTM1 and GPX1 Genes and Smoking Susceptibility in the Saudi Population.

Glutathione-S-transferase Mu1 (GSTM1) and glutathione peroxidase 1 (GPX1) are known antioxidant enzymes that help protect cells from the oxidative damage that occurs from smoking. This study explored the correlation between GSTM1 and GPX1 levels between a group of smokers with the GSTM1 and GPX1 genes in the Saudi population and a control group and investigated the genetic risk factors in the group of smokers. The control and smokers' group (n = 50; aged 22.3 ± 3.1 years; BMI 24.6 ± 5.9 kg/m2) were genotyped using quantitative polymerase chain reaction (qPCR). In comparison with the control group, the smokers' group displayed a different genotype disruption of GSTM1 and GPX1. Carriers of the homozygous (TT) genotype of GSTM1 had more than a twofold (OR = 2.71, 95% CI = 0.10-70.79, P = 1.000) smoking risk than the carriers of the heterozygous (CT) genotype. Those with the GPX1 gene showed no risk in the control and smokers' groups. Smokers with the TT/GG combination (homozygous for GPX1 and normal for GPX1) were identified as high risk (OR = 2.58, 95% CI = 0.096-69.341). The main outcomes showed no significant association between genetic polymorphism of the GSTM1 and GPX1 genes and cigarette smoking in the Saudi Arabian population. However, the results showed a slight decrease in the number of GSTM1 and GPX1 gene modifications among smokers.

An updated analysis on the association of GSTM1 polymorphism and smoking exposure with the increased risk of coronary heart disease.

ObjectiveTo undertake a meta-analysis to investigate if there is an association between the glutathione S-transferase mu 1 (GSTM1) gene polymorphism, coronary artery disease (CAD) susceptibility and smoking.MethodsElectronic databases, including PubMed®, Web of Science and Embase®, were searched for relevant case–control studies. Data were extracted and the odds ratio (OR) was calculated and appropriate statistical methods were used for the meta-analysis.ResultsThe analysis included eight studies with a total of 1880 cases with CAD and 1758 control subjects. The results of this meta-analysis demonstrated that there is no association between the GSTM1 null and CAD (OR 1.24, 95% confidence interval [CI] 1.00, 1.55). An increased risk of CAD was observed in the smoking population with the GSTM1 null genotype (OR 1.48, 95% CI 1.02, 2.15). Subgroup analyses of geographical region, genotyping method and publication language category demonstrated potential relationships among gene polymorphism, smoking and CAD.ConclusionsBased on the current literature, the GSTM1 null genotype was associated to CAD in the smoking population. The interaction between smoking and GSTM1 polymorphism may contribute to the susceptibility of CAD.

Association of CYP1A1, GSTM1 and GSTT1 gene polymorphisms with risk of prostate cancer in Algerian population

BackgroundProstate cancer is the most common cancer in the world, and its etiology involves the interaction of genetic and environmental factors. Interindividual differences observed in the metabolism of xenobiotics may be due to polymorphisms of genes encoding the detoxification enzymes. This genetic variability seems to be associated with differences in susceptibility to certain types of cancers, including prostate cancer. Our study has been made in order to investigate a possible genetic predisposition to prostate cancer in an Algerian population, through the analysis of genetic polymorphisms of three enzymes metabolizing xenobiotics namely cytochrome P450 (CYP) 1A1, glutathione S-transferase mu 1 (GSTM1) and GST theta 1 (GSTT1).MethodsThe current case–control study included 101 prostate cancer patients and 101 healthy controls. Genotyping of CYP1A1 T3801C polymorphisms and GSTM1/GSTT-null was made, respectively, by PCR-RFLP and multiplex PCR.ResultsNo significantly positive associations were found for the CYP1A1 T3801C [p = 0.71, OR = 1.23 (0.56–2.72)] and GSTM1-null [p = 0.26, OR = 1.37 (0.76–2.4)] polymorphisms and prostate cancer susceptibility. However, we detect a highly significant association between GSTT1-null genotype [p = 0.03, OR = 2.03 (1.06–3.99)], GSTM1/GSTT1-double null genotype [p = 0.027, OR = 2.6; CI (1.07–6.5)] and prostate cancer risk. Furthermore, no statistically significant differences between the studied polymorphisms and tumor parameters (the Gleason score and clinical stages of aggressiveness) at diagnosis of PCa.ConclusionsThe risk of developing prostate cancer in Algeria does not appear to be associated with CYP1A1 T3801C genotypes and GSTM1-null, but GSTT1-null and GSTM1/GSTT1-double null genotypes increased the risk of prostate cancer.

GSTM1 and GSTT1 Null Genotype Polymorphisms and Susceptibility to Arsenic Poisoning: a Meta-analysis.

The value of the glutathione S-transferase (GST) null genotype in patients with arsenic poisoning has been recognized, but the conclusions of previous studies remain inconsistent. The objective of this study was to evaluate the relationship between GST mu 1 (GSTM1) and GST theta 1 (GSTT1) null genotype polymorphisms and susceptibility to arsenic poisoning. PubMed, Medline, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), WanFang, and WeiPu databases were systematically searched for publications up to March 31, 2020. The quality of the studies was assessed using the Newcastle-Ottawa Quality Assessment Scale. The pooled odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated to estimate the relationship between GSTM1 and GSTT1 null genotype polymorphisms and arsenic poisoning. The meta-analysis was conducted using STATA 14.0 software. Nine articles with 3324 subjects were included in the meta-analysis. A significantly negative correlation was observed between the GSTM1 null genotype and susceptibility to arsenic poisoning (OR = 0.731; 95% CI: 0.536-0.999; P = 0.049; I2 = 70.5%). There was no significant correlation between the GSTT1 null genotype (OR = 1.009; 95% CI: 0.856-1.189; P = 0.915, I2 = 36.8%) and GSTM1-GSTT1 double null genotype (OR = 1.105; 95% CI: 0.670-1.822; P = 0.695; I2 = 64.7%) and the risk of arsenic poisoning. Egger's and Begg's tests indicated no publishing bias. Compared with controls, individuals with the GSTM1 null genotype were less susceptible to arsenic poisoning. The GSTT1 single null genotype and GSTM1-GSTT1 dual-null genotype were not associated with the risk of arsenic poisoning. The GSTM1 single null genotype may have potential as a genotoxic biomarker to identify individuals who are not prone to arsenic poisoning, and as a reference for guiding the prevention of arsenic poisoning.

GSTM1 and GSTT1 genetic polymorphisms and their association with antituberculosis drug-induced liver injury.

Antituberculosis (anti-TB) drugs are the most common cause of drug-induced liver injury (DILI). There are numerous studies revealing the associations between the polymorphisms of pharmacogenes and the risk of anti-TB DILI (ATDILI). In the present study, relevant studies regarding the pharmacogenes associated with ATDILI were systematically searched in PubMed and Scopus. A total of 24 genes associated with ATDILI were reported on and the top five reported genes in terms of frequency were revealed to be N-acetyltransferase 2, cytochrome P450 family 2 subfamily E member 1, glutathione S-transferases [glutathione S-transferase mu 1 (GSTM1) and glutathione S-transferase theta 1 (GSTT1)] and solute carrier organic anion transporter family member 1B1. As ATDILI may be the result of direct and indirect interactions, the encoded proteins were further analysed using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) to observe the protein-protein interactions and the associations amongst these proteins. The results suggested that only GSTT1 and GSTM1 were central proteins associated with all the other analysed proteins. Therefore, the association between GSTT1 or GSTM1 and the risk of developing ATDILI were further analysed. The results revealed that a GSTM1 deletion genotype was significantly associated with risk of ATDILI [odds ratio (OR), 1.28; 95% confidence interval (CI), 1.08-1.51; P=0.004], whereas the GSTT1 deletion genotype and GSTM1/GSTT1 dual-deletion genotype were not significantly associated with risk of ATDILI. Subgroup analysis based on ethnicity was performed and the results demonstrated a significant association between GSTM1 and ATDILI in South Asian individuals (OR, 1.48; 95% CI, 1.12-1.95; P=0.005), which has not been reported previously, to the best of our knowledge. In conclusion, GSTM1 was associated with ATDILI in South Asian individuals.

POLYMORPHIC DELETIONS OF GLUTATHIONE S-TRANSFERASES M1, T1 AND BLADDER CANCER RISK IN ALGERIAN POPULATION

Objective: Glutathione S-transferase mu 1 (GSTM1) and GST theta 1 (GSTT1) genes are two xenobiotic metabolizing genes in Phase II of the detoxification process. The polymorphisms of GSTM1, GSTT1 genes, and smoking are involved in many cancers such as bladder cancer. Our aim was to assess the role of smoking status and GSTM1 and GSTT1 null genotypes in bladder cancer development in Algerian population.Methods: The current case–control study included 175 bladder cancer patients and 188 controls matched for age, gender, and ethnic origin. The GSTM1 and GSTT1 genotypes were determined by multiplex polymerase chain reaction using blood genomic DNA. Possible associations of stage and grade with the obtained genotypes were also tested.Results: A significant associations were observed between bladder cancer risk and tobacco smoke (p value: p=1.21E-08), GSTM1 null genotype (p=0.018), GSTT1 null genotype (p=0.009), and GSTM1/GSTT1-double null genotype (p=0.001). The combined effect of smoking and testing deletions increased the risk of bladder cancer and the most important risk was observed among smokers carrying GSTM1/GSTT1-double null genotype (p=1.09E-05). No significant association was shown between stage and grade of bladder cancer and the testing genotypes.Conclusion: This study indicated that smoking, GSTM1 null, GSTT1 null, and GSTM1/GSTT1-double null genotypes individually represent a risk factor for bladder cancer in Algerian population. The interaction smoking gene increased the risk considerably. In fact, it is suggested that patients with cigarette smoking habit and combined GSTM1 and T1 genes deletion might be at increased risk of bladder cancer.

Evaluation of genetic polymorphisms in glutathione S-Transferase theta1, glutathione S-Transferase mu1, and glutathione S-Transferase mu3 in oral leukoplakia and oral squamous cell carcinoma with deleterious habits using polymerase chain reaction

Context:Oral squamous cell carcinoma (OSCC) is the sixth most common cancer in the world. As per previous studies, most patients who develop oral cancer are elderly males who are heavy users of tobacco and alcohol; however, the incidence is increasing in younger individuals and in those who neither smoke nor drink. Many of the genes that code for the detoxification enzymes are polymorphic with abnormal activity profiles.Aims and Objectives:The aim of this study was to evaluate the risk of development of oral leukoplakia (OLP) and OSCC in glutathione S-transferase polymorphisms genes in the east coast of Andhra Pradesh population with tobacco consumption habit and habit-free controls using polymerase chain reaction (PCR-restriction fragment length polymorphism).Materials and Methods:This study included 15 patients each with histologically proven epithelial dysplasia and OSCC and compared with age- and gender-related controls with no tobacco habits in any form. A volume of 2 ml of blood sample was collected into presterilized vials containing ethylenediaminetetracetic acid from each individual under aseptic conditions. DNA extraction was done from whole blood, and PCR was performed. Statistical analysis was performed using Chi-square test and odds ratio (OR) and 95% confidence intervals (CIs).Results:The results are suggestive that glutathione S-transferase mu1 (GSTM1) null was associated with increased risk of OLP (OR = 5.5, 95% CI = 1.14–26.41, P = 0.021) and OSCC (OR = 11, 95% CI = 1.99–60.5, P = 0.021). Glutathione S-transferase theta1 (GSTT1) null genotype was associated with increased risk of OLP (OR = 2.154, 95% CI = 0.74–26.672, P > 0.99) and OSCC (OR = 2.154, 95% CI = 0.74–26.672, P > 0.99). The glutathione S-transferase mu3 (GSTM3) AB + BB genotypes appear to be risk factors for OSCC (OR = 1.31, 95% CI = 0.31–5.58, P = 0.7) although statistically insignificant.Conclusion:Hence to conclude, because of small sample size in the present study, statistically insignificant results were found and this study failed to observe the relationship between GSTM3 and GSTT1 polymorphism and risk of developing OSCC and positive relationship was observed with GSTM1 polymorphism and risk of developing OSCC.

Associations Among Glutathione S-Transferase T1, M1, and P1 Polymorphisms and the Risk of Oral Leukoplakia.

The potential association between glutathione S-transferase (GST) M1, T1, P1 polymorphisms and the risk of oral leukoplakia (OLK) has been extensively studied. However, the results of previous studies have been contradictory. In an effort to resolve these different findings we performed a meta-analysis. Eligible articles were identified by a search of PubMed, the China National Knowledge Infrastructure (CNKI), MEDLINE, EMBASE, and the Web of Science databases through December 1, 2015. Crude odds ratios (ORs) with 95% confidence intervals were used to evaluate the risk of OLK by tobacco use, ethnicity, and OLK subtype. A total of 3122 cases and 6037 controls were included in the meta-analysis. The results indicated that the glutathione S-transferase Mu1 (GSTM1) and glutathione S-transferase T1 (GSTT1) null polymorphisms increase the risk of OLK (OR = 1.838, 95% CI = 1.582-2.134 and OR = 1.337, 95% CI = 1.132-1.579, respectively), especially in the groups with tobacco use (OR = 2.478, 95% CI = 2.032-3.020 and OR = 2.034, 95% CI = 1.486-2.783, respectively). Conversely the glutathione S-transferase P1 (GSTP1) polymorphism did not demonstrate a significant relationship with OLK risk (OR = 1.139, 95% CI = 0.900-1.442). The GSTM1 and GSTT1 null polymorphisms were identified as being significantly associated with an increased risk of OLK within the German and Indian populations: German subgroup (GSTM1: OR = 11.555, 95% CI = 7.465-17.884), Indian subgroup (GSTM1: OR = 1.333, 95% CI = 1.084-1.638; GSTT1: OR = 1.332, 95% CI = 1.057-1.679). Our findings provide evidence that the GSTT1 and GSTM1 null polymorphisms may be risk factors of OLK, especially for persons who use tobacco, whereas the GSTP1 polymorphism does not contribute to the development of OLK. Thus, detection of GSTT1 and GSTM1 null polymorphisms may be promising biomarkers for the OLK susceptibility.

Genotypes of GSTM1 and GSTT1: Useful determinants for clinical outcome of bladder cancer in Pakistani population

BackgroundIncidence of bladder cancer has increased rapidly worldwide in the past few years. Environmental as well as genetic factors are involved in the etiology of bladder cancer. Glutathione S transferase mu 1 (GSTM1) and glutathione S transferase theta 1 (GSTT1) genes are two xenobiotic metabolizing genes in phase II of detoxification process. AimThe current study was aimed to find out the association of different environmental factors and GSTM1 and GSTT1 gene polymorphisms with susceptibility to bladder cancer in Pakistani population. MethodBladder cancer cases (236) and control blood samples (270) were screened using phenol chloroform method of DNA extraction followed by multiplex PCR. ResultsWith respect to age; bladder cancer was more prevalent in age >60years and low grade tumors were more frequent than high grade tumors. Smokers had a significantly higher incidence rate of cancer; also family history of cancer was found to be strongly associated (P<0.05) with bladder cancer. Commonly reported symptoms by the patients of bladder cancer were hematuria, lower urinary tract symptoms (LUTS) and flank pain. A larger number of patients had undergone surgery, chemotherapy and radiotherapy. Similarly GSTM1 (OR 2.24; CI 1.5–3.2; P=0.0001) and GSTT1 (OR 2.9; CI 1.4–6.1; P=0.002) gene deletion showed a highly significant association with bladder cancer. Simultaneous deletions of both GSTM1 and GSTT1 genes also showed highly significant association (OR 5.3; CI 2.1–13.1; P=0.0001) with cancer risk. No association was found when both of the two genes deletion was compared with bladder cancer among smokers. ConclusionThis study suggests that GSTM1 and GSTT1 gene polymorphisms may be associated with increased susceptibility toward bladder cancer in Pakistani population.

GSTM1 gene polymorphism and the risk of colorectal cancer in a Saudi Arabian population.

The enzyme glutathione S-transferase Mu 1 (GSTM1) is encoded by the GSTM1 gene. Polymorphisms in GSTM1 affect the detoxifying function of the enzyme variants. This forms the basis of the debate about the impact of the GSTM1 null/present genotype on colorectal carcinoma risk. We tested the potential influence of GSTM1 polymorphisms on the development of colorectal cancer. DNA extracted from 83 samples taken from patients that were previously diagnosed as having colorectal carcinoma and from 35 control subjects who did not have colorectal carcinoma were amplified. GSTM1 genotypes were determined by DNA sequencing. The current study revealed that the majority (69/83, 83%) of colorectal cancer cases harbored the null genotype (GSTM1*0/*0), and the remaining 14 (17%) cases harbored either the GSTM1wt/wt or the GSTM1wt/*0 genotype. In contrast, among the control cases, 23 (65%) had the null genotype (GSTM1*0/*0) and 12 (35%) had either the GSTM1wt/wt or the GSTM1wt/*0 genotype. The current report emphasizes the impact of the GSTM1 null genotype on the increased risk of colorectal carcinoma in Saudi Arabia.

Relevance of GSTM1, GSTT1 and GSTP1 Gene Polymorphism to Breast Cancer Susceptibility in Mizoram Population, Northeast India.

The enzymes encoded by glutathione S-transferase mu 1 (GSTM1) and theta 1 (GSTT1) genes are involved in the metabolism of wide range of carcinogens that are ubiquitous in the environment. Homozygous deletions of the GSTM1 and GSTT1 genes are commonly found and result in lack of enzyme activity. This study was undertaken to evaluate the association between GSTM1, GSTT1 and GSTP1 gene polymorphism and breast cancer risk in Mizoram population. Odd ratio (OR) and 95% confidence interval (CI) from conditional logistic regression model were used to estimate the association between genetic polymorphism and breast cancer risk. The GSTM1 and GSTT1 null genotypes were associated with an increased risk of breast cancer [OR = 10.80 (95% CI 1.16-100.43)]. The risk of breast cancer associated with the GSTT1 null genotype was observed to be low among postmenopausal women. When considered together, GSTM1 and GSTT1 genotypes were found to be associated with an increased risk of breast cancer. The relationship between GSTM1 and GSTT1 gene deletions and breast cancer risk was substantially altered by consumption of Smoked Meat/Vegetable. In the present study, GSTP1Ile105Val (rs1695) polymorphism was related to breast cancer susceptibility or phenotype. Our data provides evidence for substantially increased risk of breast cancer associated with GSTM1 and/or GSTT1 homozygous gene deletions in Mizoram population.

GSTM1 and GSTM5 Genetic Polymorphisms and Expression in Age-Related Macular Degeneration

ABSTRACTPurpose: Previously, two cytosolic antioxidant enzymes, Glutathione S-transferase Mu 1 (GSTM1) and Mu 5 (GSTM5), were reduced in retinas with age-related macular degeneration (AMD). This study compared genomic copy number variations (gCNV) of these two antioxidant enzymes in AMD versus controls.Methods: Genomic copy number (gCN) assays were performed using Taqman Gene Copy Number Assays (Applied Biosystems, Darmstadt, Germany) in technical quadruplicate for both GSTM1 and GSTM5. Peripheral leukocyte RNA levels were compared with controls in technical triplicates. Statistical comparisons were performed in SAS v9.2 (SAS Institute Inc., Cary, NC).Results: A large percentage of patients in both AMD and age-matched control groups had no copies of GSTM1 (0/0). The mean gCN of GSTM1 was 1.40 (range 0–4) and 1.61 (range 0–5) for AMD and control, respectively (p = 0.29). A greater percentage of control patients had > 3 gCNs of GSTM1 compared with AMD, respectively (15.3% versus 3.0%, p = 0.004). The gCN of GSTM5 was 2 in all samples except one control sample. The relative quantification of GSTM1 and GSTM5 mRNA from peripheral blood leukocytes in patients showed significant differences in relative expression in AMD versus control (p < 0.05). Peripheral blood leukocyte mRNA and gCN were not significantly correlated (p = 0.27).Conclusion: Since high copy numbers of GSTM1 are found more frequently in controls than in AMD, it is possible that high copy number leads to increased retinal antioxidant defense. Genomic polymorphisms of GSTM1 and GSTM5 do not significantly affect the peripheral blood leukocyte mRNA levels.

Polymorphisms of GSTM1, GSTT1, and p53 in Goiânia, Goiás.

Genetic polymorphisms are defined as changes within the DNA sequences of genes that have frequencies in the population higher than 1%. The glutathione S-transferases play an important role in the cellular detoxification systems involved in oxidative stress that can lead to accumulation of reactive oxygen species. Epidemiological studies have suggested that individuals with homozygous deletion of glutathione S-transferase mu 1 (GSTM1) and glutathione S-transferase theta 1 (GSTT1) are at higher risk of developing several types of neoplasias. The p53 protein is highly expressed in tumors and transformed cells, and the p53 is a classical tumor suppressor gene involved in regulating cell growth and development. In this study, we investigated the prevalence of polymorphisms in the p53, GSTM1, and GSTT1 genes in a population from Goiânia. We evaluated the polymorphisms of these genes in peripheral blood samples. The null or present polymorphism of GSTM1 and GSTT1 genes and Arg/Pro of the p53 gene were analyzed. Our results revealed a higher frequency of the GSTM1-null polymorphism (72.4%) than the GSTM1-present genotype (27.6%). For GSTT1, we observed higher frequency for the null genotype (65.5%) compared to the present genotype (34.5%). Analysis of p53 gene polymorphisms showed a higher frequency for the genotype Arg/Pro (66%) and a lower frequency for the Arg/Arg (23%) and Pro/Pro (11%) genotypes. It is essential to understand polymorphism frequencies in different populations and to evaluate the role of genetic polymorphisms and their effects on health.

Effect of CYP1A1 and GSTM1 genetic polymorphisms on bone tumor susceptibility.

Tumor gene polymorphisms are often associated with individual susceptibility to genetic diseases. Cytochrome P4501A1 (CYP1A1) and glutathione S-transferase mu 1 (GSTM1) gene polymorphisms are closely related to the susceptibility of the body to chemical carcinogens in the environment. Therefore, we explored the relationship between CYP1A1 and GSTM1 gene polymorphisms and susceptibility to bone tumors. Multiplex-polymerase chain reaction (PCR), allelic-specific PCR, and PCR-restriction fragment length polymorphism techniques were used to analyze CYP1A1 and GSTM1 gene polymorphisms in 52 bone tumor patients and 100 healthy subjects. The allelic variation frequency of the CYP1A1 gene at exon 7 (Ile 462 Val) in bone tumor patients was 0.462, which was significantly higher than that in the normal controls (0.223). The frequency of the absence of the GSTM1 homozygous genotype in the patients (0.65) was also markedly higher than that in the control group (0.41). Subjects with CYP1A1 Val/Val homozygous mutations and absence of the GSTM1 homozygous genotype were at markedly increased risk of developing bone tumors [ORs 4.15 (95%CI: 1.268-13.30) and 2.35 (95%CI: 1.15-4.85), respectively]. The OR for the combined effect of the CYP1A1 and GSTM1 gene polymorphisms was 8.55 (95%CI: 1.75-41.50). CYP1A1 and GSTM1 polymorphisms are genetic risk factors in patients with bone tumors, and the allelic variation of these genes increases the risk of bone tumor occurrence.

Genetic polymorphisms of glutathione S-transferase Mu 1, glutathione S-transferase theta 1, and glutathione S-transferase P1 in oral squamous cell carcinoma: A case-control study in Iranian population

Background: Gene variability related to activation and detoxification of procarcinogens affects the susceptibility to oral squamous cell carcinoma (OSCC). The results of numerous studies investigating the interrelationship between polymorphisms of glutathione S- transferase enzymes are not conclusive and there are little data regarding this topic on Iranian population. Aims and Objectives: This study aimed to investigate the genetic polymorphisms in glutathione S-transferase Mu 1 (GSTM1), glutathione S-transferase theta 1 (GSTT1), and glutathione S-transferase P1 (GSTP1) and the association with the risk of OSCC in Iranian population. Materials and Methods: The genetic polymorphisms of GSTM1, GSTT1, and GSTP1 genes were investigated in 35 Iranian patients with the OSCC and 60 age-sex matched controls. GSTP1 genotyping was performed by polymerase chain reaction (PCR)-restriction fragment length polymorphism method and GSTM1 and GSTT1 genotyping was amplified with PCR using specific primers. Odds ratios (ORs) and their 95% confidence intervals (CIs) were obtained using SPSS 17 and the risk of OSCC in relation to GSTM1, GSTT1, and GSTP1 polymorphism was defined. Results: The prevalence of GSTM1 and GSTT1 null genotypes in OSCC group were significantly higher than the control group.(OR = 2.6, 95% CI = 1.04-6.5; P = 0.01 for GSTM1) (OR = 11, 95% CI = 9-31; P = 0.001 for GSTT1). The GSTP1 valine polymorphism was not significantly different between the study groups (P = 0.145). Conclusions: GSTM1 and GSTT1 null genotypes may increase the risk for OSCC development in Iranian patients.

GSTM1 and GSTT1 Null Polymorphisms and Childhood Acute Leukemia Risk: Evidence from 26 Case-Control Studies

Several molecular epidemiological studies have been conducted to examine the association between glutathione S-transferase mu-1 (GSTM1) and glutathione S-transferase theta-1 (GSTT1) null polymorphisms and childhood acute leukemia; however, the conclusions remain controversial. We performed an extensive meta-analysis on 26 published case-control studies with a total of 3252 cases and 5024 controls. Crude odds ratios (ORs) with 95% confidence interval were used to assess the strength of association between childhood acute leukemia risk and polymorphisms of GSTM1 and GSTT1. With respect to GSTM1 polymorphism, significantly increased risk of childhood acute leukemia was observed in the overall analysis (OR = 1.30; 95%CI, 1.11-1.51). Furthermore, a stratification analysis showed that the risk of GSTM1 polymorphism are associated with childhood acute leukemia in group of Asians (OR = 1.94; 95%CI, 1.53-2.46), Blacks (OR = 1.76; 95%CI, 1.07-2.91), ALL (OR = 1.33; 95%CI, 1.13-1.58), ‘< 100 cases and <100 controls’ (OR = 1.79; 95%CI, 1.21-2.64), ‘≥ 100 cases and ≥ 100 controls’ (OR = 1.25; 95%CI, 1.02-1.52), and population-based control source (OR = 1.40; 95%CI, 1.15-1.69). With respect to GSTT1 polymorphism, significant association with childhood acute leukemia risk was only found in subgroup of Asian. This meta-analysis supports that GSTM1 null polymorphism is capable of causing childhood acute leukemia susceptibility.

Association between GSTM1 polymorphism and DNA adduct concentration in the occupational workers exposed to PAHs: A meta-analysis

Increasing investigations have been conducted on the association between DNA adducts and glutathione S-transferase Mu 1 (GSTM1) null genotype in occupationally exposed population. However, the results were controversial. The objective of the present study was to perform a meta-analysis to better understand the possible association between DNA adduct levels and GSTM1 genotype in occupational exposure population. Among a total of 167 literature searched from frequently-used databases, 7 articles corresponding to the specific criteria were enrolled into the meta-analysis. There was a significant increase of DNA adduct levels in occupationally exposed workers compared with control groups (p=0.003). Additionally, DNA adduct levels among the carriers of null GSTM1 were significantly higher than those of active GSTM1 carriers in exposure workers (p=0.017). Egger's test (p=0.056) and Begg's test (p=0.368) indicated that there was no evidence of publication bias. In conclusion, workers exposed to polycyclic aromatic hydrocarbons (PAHs) were at high risk to form DNA adducts, and the occupationally exposed workers who carried null GSTM1 were more susceptible to damage from PAHs.