A glutathione transferase in human leukocytes as a marker for the susceptibility to lung cancer

Distinct COPD subtypes in former smokers revealed by gene network perturbation analysis

BACKGROUND

Chronic obstructive pulmonary disease (COPD) varies significantly in symptomatic and physiologic presentation. Identifying disease subtypes from molecular data, collected from easily accessible blood samples, can help stratify patients and guide disease management and treatment.

METHODS

Blood gene expression measured by RNA-sequencing in the COPDGene Study was analyzed using a network perturbation analysis method. Each COPD sample was compared against a learned reference gene network to determine the part that is deregulated. Gene deregulation values were used to cluster the disease samples.

RESULTS

The discovery set included 617 former smokers from COPDGene. Four distinct gene network subtypes are identified with significant differences in symptoms, exercise capacity and mortality. These clusters do not necessarily correspond with the levels of lung function impairment and are independently validated in two external cohorts: 769 former smokers from COPDGene and 431 former smokers in the Multi-Ethnic Study of Atherosclerosis (MESA). Additionally, we identify several genes that are significantly deregulated across these subtypes, including DSP and GSTM1, which have been previously associated with COPD through genome-wide association study (GWAS).

CONCLUSIONS

The identified subtypes differ in mortality and in their clinical and functional characteristics, underlining the need for multi-dimensional assessment potentially supplemented by selected markers of gene expression. The subtypes were consistent across cohorts and could be used for new patient stratification and disease prognosis.

Proteome analysis identified proteins associated with mitochondrial function and inflammation activation crucially regulating the pathogenesis of fatty liver disease

Background

Fatty liver disease prevalently occurs in commercial postpartum dairies, resulting in a worldwide high culling rate because of their subsequent limitations of production and reproduction performance.

Results

Fatty liver-specific proteome and acetylome analysis revealed that energy metabolism suppression closely associated with mitochondrial dysfunction and inflammation activation were shown to be remarkable biological processes underlying the development of fatty liver disease, furthermore, acetylation modification of proteins could be one of the main means to modulate these processes. Twenty pivotal genetic factors/genes that differentially expressing and being acetylation modified in liver were identified and proposed to regulate the pathogenesis of fatty liver dairies. These proteins were confirmed to be differentially expressing in individual liver tissue, eight of which being validated via immunohistochemistry assay.

Conclusions

This study provided a comprehensive proteome and acetylome profile of fatty liver of dairy cows, and revealed potential important biological processes and essential regulators in the pathogenesis of fatty liver disease. Expectantly, understanding the molecular mechanisms of the pathogenesis of fatty liver disease in dairies, as an animal model of non-alcoholic fatty liver disease (NAFLD) in human beings, which is a clinico-pathologically defined process associated with metabolic syndrome, could inspire and facilitate the development of efficacious therapeutic drugs on NAFLD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07950-2.

Risk of Colorectal Carcinoma May Predispose to the Genetic Variants of the GST, CYP450, and TP53 Genes Among Nonsmokers in the Saudi Community

PURPOSE

Colorectal carcinoma (CRC) represents a considerable public health burden in Saudi Arabia. Several candidate genes and genetic variants have been associated with morbidity and mortality among patients with CRC. We explored whether allelic variants of the GSTM1, GSTT1, CYP450 (rs4646903 and rs1048943), and TP53 (rs1042522) genes predisposed nonsmoking Saudi individuals to increased risk for CRC.

PATIENTS AND METHODS

DNA from buccal cells of 158 participants (80 with CRC and 78 healthy controls) were analyzed for five SNPs using conventional PCR and TaqMan genotyping assays. The SNPStats software was utilized to choose the best interactive inheritance mode for selected SNPs (https://www.snpstats.net).

RESULTS

The mean age of diagnosis was 62.4±13.5 years (range, 40-83 years), with those aged 71-80 years and those aged 40-50 years accounting for the most diagnoses (35.7% and 28.6% of diagnosis, respectively). The GSTM1 and TP53 rs1042522 SNPs were associated with CRC (OR= 3.7; P< 0.0001, and OR= 1.6; P= 0.033, respectively). A plausible contribution to CRC was observed for the GSTM1 and TP53 rs1042522 SNPs (x ² _Yates= 14.7; P= 0.00013, and x ² _Yates= 11.2; P= 0.0008, respectively), while the GSTT1 null variant did not affect risk. Heterozygosity in the CYP450 (rs4646903 and rs1048943 SNPs) was associated with a significant risk for CRC. The GSTM1/GSTT1 and CYP450 rs4646903/rs1048943 SNP pairs were in linkage disequilibrium, and the associations were statistically significant (P= 0.01 and P= 4.6x10^‒7, respectively).

CONCLUSION

The GSTM1 and TP53 rs1042522 variants can increase the development of CRC in Saudi nonsmokers. Even the presence of one copy of a variant allele in the CYP1A1 gene can predispose CRC risk. Additional studies should also examine other SNP combinations with lifestyle factors that may help prevent, rather than facilitate, colorectal tumorigenesis.

Comparative liver metabolic enzyme activity of cytochrome P450 and glutathione-S-transferase in crocodile (Crocodylus siamensis) and livestock

This study aimed to compare the metabolism of detoxification liver enzymes activity of CYP1A2, CYP2E1, the GST enzymes activity for class pi, mu, alfa, and the universal GST between crocodile and livestock, plus the relationship of these two enzyme activities in the crocodile. Interestingly, the CYP1A2 and CYP2E1 were existent in the freshwater crocodile livers microsomal enzyme activities, and these two enzymes could be determined in both pig and chicken. Also, the universal GST, alpha, mu, and pi class of phase II were presented in the crocodile liver cytosolic fractions, and these three enzymes could also be found in pig and chicken. The kinetic activity (Vmax/Km ratio) of GST activity towards CDNB was higher in the crocodile than chicken, and pig; 80.02, 57.80 and 45.25 ml/min/mg protein, respectively. The Vmax/Km ratio GST activity towards t-PBO was highest in crocodile. In contrast, the GST activity towards EA was highest in pig, chicken and crocodile in this order. However, the Vmax/Km ratio GST activity towards CHP was very low in all species. The crocodile liver microsome fraction could metabolites AFB1 to AFM1, suggesting that the CYP1A2 activity was actively presented. The kinetic enzyme activity of crocodile liver towards CDNB revealed the highest velocity compared with other livestock species; this indicates that crocodile liver enzyme activities were very active for the detoxification function towards all xenobiotic, especially for GST activity, towards carcinogenic agent when compared with other livestock.

Polymorphism of xenobiotic metabolizing gene and susceptibility of epithelial ovarian cancer with reference to organochlorine pesticides exposure

The transformation of ovarian surface epithelial cells, stromal cells, sex cord, or germ cells initiates ovarian malignancy. Epithelial ovarian cancer (EOC) is clinically silent with vague, non-specific symptomatology and is generally diagnosed at an advanced stage, resulting in a high mortality rate. The known main etiological factors are: age at menarche and menopause (early menarche or late menopause), use of oral contraception (estrogen and/or progesterone), family history, genetic factors, inflammation, occupational and environmental exposure. The study is intended to assess the association between blood organochlorine pesticide (OCP) levels and polymorphic status of phase I and phase II metabolizing enzymes (CYP1A1, GSTM1, and GSTT1) in the pathogenesis of epithelial ovarian cancer. The study included 200 subjects in total, of which 100 were epithelial ovarian cancer cases and 100 were controls. Estimation of blood organochlorine pesticide levels was carried out using gas chromatography and significantly high levels of beta-hexachlorocyclohexane (β-HCH), endosulfan-I, endosulfan-II, dichlorodiphenyltrichloroethane (pʹpʹ-DDT), dichlorodiphenyldichloroethylene (pʹpʹ-DDE) were observed in cases as compared to controls ( P-value = 0.029, 0.042, 0.044, 0.039 and 0.037 respectively). For studying the polymorphism of CYP1A1, GSTM1/T1, PCR-RFLP, AS-PCR and multiplexing were performed and the frequency of null deletion of GSTM1/T1 was significantly higher in epithelial ovarian cancer cases. Regression model testing was also performed to check the interactive effect of organochlorine pesticide levels and polymorphic variant of genes keeping CA-125 as the dependent variable and observed a statistically significant role of genotypic/environmental interaction in epithelial ovarian cancer cases in the North Indian population.

Impact statement

Among pervasive environmental toxins, OCPs are one of the largest and most hazardous classes of contaminants in use around the world. Because these compounds possess the estrogen mimicking properties, the accumulation of these compounds in the human body may be a risk for several hormone-dependent diseases. EOC is hormonally dependent cancer and the mortality rate due to this disease is increasingly prevalent, and it has become imperative to explore the role of OCPs in the disease pathogenesis. The present study highlights the significant association of high OCPs level in the disease pathogenesis. It is also observed that the polymorphism in xenobiotic metabolism enzymes alters the predisposition of OCPs. The synergistic effect of gene polymorphism (CYP1A1, GSTM1, and GSTT1) and non-occupational exposure to OCPs was also assessed considering CA125 level as dependent variable with the risk of EOC and concluded that there exist a potential role of genotypic/environmental interaction in the etiology of EOC.

Lung cancer susceptibility from GSTM1 deletion and air pollution with smoking status: a meta-prediction of worldwide populations

Glutathione S transferase mu 1 (GSTM1) gene has been associated with lung cancer (LC) risk, for GSTM1 enzyme playing a vital role in detoxification pathway and protective against toxic insults. The major objective of this study was to investigate GSTM1 deletion pattern and its association with LC in the world’s population by using meta-prediction techniques. The secondary objective was to examine the effects of air pollution, smoking status, and other factors for gene-environment interactions with GSTM1 deletion and LC risk. We completed a comprehensive search to yield a total of 170 studies (40,296 cases and 48,346 controls) published from 1999 to 2017 for meta-analyses. The results revealed that GSTM1 deletion type was associated with increased risk of LC, while GSTM1 present type provided protective effect for all populations combined worldwide. Subgroup analysis on the rank order of risks from highest to lowest, among racial–ethnic groups, were Chinese, South East Asian, other North Asian, European, and finally American. Additional predictive analyses presented that air pollution played a significant role with increased risks of GSTM1 deletion and LC susceptibility, and the risks increased for smokers with higher levels of air pollution. Based on the findings of meta-predictive analysis, increased air pollution levels and smoking status presented additive effects to the LC risk susceptibilities and GSTM1 gene polymorphisms, for gene-environment interactions. Future studies are needed to examine gene-environment interactions for GSTM1 interacting with environmental factors and dietary interventions to mitigate the toxic effects, for LC prevention.

CYP2E1 and GSTM1 gene polymorphisms, environmental factors, and the susceptibility to lung cancer

OBJECTIVE

To investigate the relationships between the CYP2E1 RsaI polymorphism, GSTM1 polymorphism, and the susceptibility to lung cancer, along with the interactions between environmental factors and these genes.

METHODS

A case-control study was carried out to explore the independent effect of gene polymorphisms on risk of lung cancer, and the combined effects of gene loci. The stratification analysis of age, sex, smoking, and drinking combined with positive loci was also analyzed, and any interaction was identified.

RESULTS

The logistic regression analysis showed that there were statistical relationships between the CYP2E1 RsaI TT genotype and lung cancer, GSTM1 (-) and lung cancer. The combined effect's analysis of these 2 loci showed that, with an increase in the number of risk alleles, the risk of lung cancer also increased (supposing 0 risk allele as the reference group). Subjects carrying 3 risk alleles had the highest risk of developing lung cancer with an adjusted OR = 10.38 (95% CI 2.10-51.35). Stratified analysis showed that, in women, nonsmoking subjects, or nondrinking subjects, the combined effects could increase the risk of lung cancer; no heterogeneity was found between these layers except sex. The interaction analysis showed that, supposing the male, GSTM1 (+) genotype as the reference, the female, GSTM1 (-) genotype had a significantly increased risk of lung cancer (OR = 2.17 [1.01-4.70]); when the non-smoking, GSTM1 (+) genotype subjects was the reference group, smoking, GSTM1 (+) genotype subjects and smoking, GSTM1 (-) genotype subjects had significantly higher risk of lung cancer (OR = 2.00 [1.01-3.96], OR = 2.89 [1.28-6.54]).

CONCLUSION

CYP2E1 RsaI TT genotype was a protective factor against the development of lung cancer, while GSTM1 (-) genotype was a risk factor for lung cancer. Increases in the number of the risk alleles also increased lung cancer risk. GSTM1 (-) genotype, sex, and smoking status might interact in the incidence of lung cancer.

Predictive assessment in pharmacogenetics of Glutathione S-transferases genes on efficacy of platinum-based chemotherapy in non-small cell lung cancer patients

The influences of glutathione s-transferase P1, M1, and T1 variants on the efficacy of platinum-based chemotherapy in non-small cell lung cancer (NSCLC) patients were inconsistent in previous studies. Our meta-analysis enrolled 31 publications including 5712 patients and provided more convincing and reliable conclusions. Results showed that GSTP1 IIe105Val IIe/Val and Val/Val Asian patients were more likely to have better response rates compared to IIe/IIe patients (odds ratio (OR) = 1.592, 95% confidence intervals (CIs), 1.087-2.332, P = 0.017). The Asian patients bearing the favorable GSTM1 null genotype were more likely to have better response rates to platinum-based chemotherapy compared to those patients with the unfavorable GSTM1 present genotype (OR = 1.493 (1.192-1.870), P < 0.001). Caucasian lung cancer patients bearing GSTT1 null genotype might be more closely associated with shorter survival time and higher risks of death than the GSTT1 present patients (hazard ratio (HR) = 1.423, CI = 1.084-1.869, P = 0.011). Our meta-analysis suggested that the GSTP1 IIe105Val, GSTM1 and GSTT1 null variants might be predictive factors for the efficacy of platinum-based chemotherapy to NSCLC patients. The use of GSTP1 IIe105Val, GSTM1 and GSTT1 null polymorphisms as predictive factors of efficacy of personalized platinum-based chemotherapy to NSCLC patients requires further verification with multi-center, multi-ethnic and large-sample-size pharmacogenetic studies.

Genotype and Phenotype of Glutathione-S-Transferase in Patients with Head and Neck Carcinoma

OBJECTIVE: Association of glutathione-S-transferase M1 (GSTM1) polymorphisms and cancer has been demonstrated. Possible underlying mechanisms and genotype-phenotype correlations are not adequately investigated. The aim of this study was to investigate the influence of the GSTM1-null-genotype on the level of GSTM enzyme concentration and on the enzyme activity of GST in patients with head and neck cancer (HNC).

METHODS: We investigated in 83 patients and 91 healthy controls the GSTM1 polymorphisms, GSTM1 protein concentration, GSTM1 protein in tumor tissues, and total GST enzyme activity.

RESULTS: Total GST enzyme activity was significantly lower in patients with HNC (208 ± 9 μmol/min1) than in controls (264 ± 11 μmol/min1, P < 0.0001) but did not depend on GSTM1-genotype ( P = 0.1). GSTM protein concentration in null-genotype patients (3.6 ± 2.5 μg/mL, mean ± SE) was significantly lower than in GSTM1 allele carriers (26.7 ± 9.6 μg/ml, P < 0.0001); GSTM protein expression did not depend on GSTM1-genotype ( P > 0.5).

CONCLUSION: GST enzyme activity in patients with HNC is suppressed, indicating impaired detoxification capacity of tobacco-smoke-related carcinogens. This suppression is not correlated with the GSTM1-genotype. (Otolaryngol Head Neck Surg 2004;130:718-25.)

Association of CYP1A1 and GSTM1 Polymorphisms With Oral Cancer Susceptibility: A Meta-Analysis

Our meta-analysis was aimed to evaluate the association of CYP1A1 and glutathione-S-transferase M1 (GSTM1) polymorphisms with oral cancer susceptibility.The related articles were searched in PubMed, Embase, and CNKI databases. Fifty eligible studies were included in our meta-analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the relationship of CYP1A1 (rs4646903 and rs1048943) and GSTM1 polymorphisms with oral cancer risk. A random-effects model or fixed-effects model was employed depending on the heterogeneity.In overall analysis, CYP1A1 rs4646903 polymorphism was associated with the risk of oral cancer (CC vs TT: OR 1.65, 95% CI 1.33-2.05; CC vs TC+TT: OR 1.77, 95% CI 1.48-2.11; C vs T: OR 1.17, 95% CI 1.07-1.28), whereas rs1048943 showed no obvious association with oral cancer susceptibility. Moreover, subgroup analysis by ethnicity demonstrated that rs4646903 and rs1048943 both related with increased risk of oral cancer in Asians. Moreover, the analysis based on source of control suggested that rs4646903 could increase the risk for oral cancer in both population- and hospital-based populations, whereas no remarkable relationship of rs1048943 with oral cancer susceptibility was observed. For GSTM1 gene, null genotype appeared to be a risk factor for oral cancer (null vs present: OR 1.23, 95% CI 1.12-1.34), which was also proved in the subgroup analysis.The results demonstrated that CYP1A1 rs4646903 and null genotype of GSTM1 polymorphisms might serve as risk factors for oral cancer.

Blood antioxidant status in coal dust induced respiratory disorders: a longitudinal evaluation of multiple biomarkers

To investigate the involvement of oxidative stress in coaldust induced respiratory disorders, red blood cell and serum antioxidants in 66 coal miners were related to 5-year changes in coal workers' pneumoconiosis (CW P), chronic bronchitis, and lung function decrease (n = 40). Reduced (GSH) and oxidized (GSSG) glutathione concentrations, glutathione peroxidase (Gpx), glutathione-S-transferase (GST), superoxide dismutase (SOD), and catalase activities were measured in erythrocytes and vitamin A, vitamin E and iron were determined in serum. Changes in CWP were determined by chest radiography, chronic bronchitis was determined from a validated questionnaire and lung function decline was calculated by linear regression for a 10 year interval before blood sampling. SOD activity was increased in miners with progression of CWP (2308±156 vs 1703±155 U g(-1) Hb, p < 0.05), and GSH was reduced in those with chronic bronchitis at follow-up (3.53±0.16 vs 4.0±0.09 mmol g(-1) Hb, p < 0.01). Stepwise discriminant analysis showed that for both pneumoconiotic and non-pneumoconiotic respiratory disease in this cohort, increased enzymatic antioxidants (i.e. Gpx, Catalase, SOD) were high risk factors, while increased 'nonenzym atic' antioxidants (i.e. vitamin E, GSH) indicated reduced risk. GST activity showed discriminative power in two ways, i.e. decreased activity in those at risk for CWP, but increased in those with rapid decline in FEV1. We conclude that the multiple marker approach applied here shows the relevance of interpretation of total 'antioxidant status' versus single antioxidant measurements in health screening of individuals at risk for respiratory impairments.

Glutathione S-transferase polymorphisms (GSTM1, GSTT1 and GSTP1) and their susceptibility to renal cell carcinoma: an evidence-based meta-analysis

Background

The association of the three Glutathione S-transferases (GSTs) polymorphisms (GSTM1, GSTT1 and GSTP1) genotypes with their individual susceptibilities to renal cell carcinoma (RCC) has not been well established. We performed a quantitative meta-analysis to assess the possible associations between the GSTM1, GSTT1 and GSTP1 genotypes and their individual susceptibilities to renal cell carcinoma.

Methods

We systematically searched the PubMed, CNKI and Embase databases to identify the relevant studies. Finally, 11 eligible studies were selected. The pooled odds ratios (ORs) with their 95% confidence intervals (CIs) were used to assess the association between the GSTs polymorphisms and the risk of RCC. Multiple subgroup analyses and quality assessment of the included studies were performed based on the available information.

Results

None of the GSTs polymorphisms had a significant association with the RCC risk. Similar results were found in the subgroup analyses, except for the GSTs polymorphisms in the situations described below. The GSTM1 and GSTT1 active genotypes in subjects exposed to pesticides (GSTM1: OR = 3.44; 95% CI, 2.04–5.80; GSTT1: OR = 2.84; 95% CI, 1.75–4.60), most of the GSTs genotypes in Asian populations (GSTT1: OR = 2.39, 95% CI = 1.63–3.51; GSTP1: Dominant model: OR = 1.50, 95% CI = 1.14–1.99; Additive model: OR = 1.39, 95% CI = 1.12–1.73; AG vs. AA: OR = 1.47, 95% CI = 1.10–1.97; GG vs. AA: OR = 1.82, 95% CI = 1.07–3.09) and the dual null genotype of GSTT1-GSTP1 (OR = 2.84, 95% CI = 1.75–4.60) showed positive associations with the RCC risk.

Conclusion

Our present study provides evidence that the GSTM1, GSTT1 and GSTP1 polymorphisms are not associated with the development of RCC. However, more case-control studies are needed for further confirmation.

Association of GSTT1 gene polymorphisms with the risk of prostate cancer: an updating meta-analysis

It has been demonstrated that the glutathione S-transferase (GST) superfamily helps remove carcinogens from the body and thus might be associated with prostate cancer risk. In recent years, GSTT1 polymorphism has been extensively studied as a potential prostate cancer risk factor; however, the results are inconsistent. To investigate the association between GSTT1 and prostate cancer, we conducted a meta-analysis of 33 studies with 6,697 prostate patients and 7,643 controls. For GSTM1 null versus present genotype, the random effects odds ratio was 0.98 (95 % confidence interval (CI) 0.83-1.16) based on a wide population. Subgroup analyses in the different ethnic groups and different controls were performed. The OR was 1.01 (95 % CI 0.86-1.19) in Caucasians, 1.01 (95 % CI 0.70-1.47) in Asians, and 0.77 (95 % CI 0.42-1.42) in Africans. The OR was 0.98 (95 % CI 0.82-1.16) in non-benign prostate hyperplasia (BPH) controls and 1.09 (95 % CI 0.66-1.79) in BPH controls. In conclusion, our present meta-analysis demonstrates that there is no association between GSTT1 polymorphism and prostate cancer, even in the sub-analysis concerning different races and control sources. The direction of further research should focus not only on the simple relationship of GSTT1 and prostate cancer but also on gene-environment interaction and distinctions of different GSTs.

Glutathione transferases, regulators of cellular metabolism and physiology

BACKGROUND

The cytosolic glutathione transferases (GSTs) comprise a super family of proteins that can be categorized into multiple classes with a mixture of highly specific and overlapping functions.

SCOPE OF REVIEW

The review covers the genetics, structure and function of the human cytosolic GSTs with particular attention to their emerging roles in cellular metabolism.

MAJOR CONCLUSIONS

All the catalytically active GSTs contribute to the glutathione conjugation or glutathione dependant-biotransformation of xenobiotics and many catalyze glutathione peroxidase or thiol transferase reactions. GSTs also catalyze glutathione dependent isomerization reactions required for the synthesis of several prostaglandins and steroid hormones and the catabolism of tyrosine. An increasing body of work has implicated several GSTs in the regulation of cell signaling pathways mediated by stress-activated kinases like Jun N-terminal kinase. In addition, some members of the cytosolic GST family have been shown to form ion channels in intracellular membranes and to modulate ryanodine receptor Ca(2+) channels in skeletal and cardiac muscle.

GENERAL SIGNIFICANCE

In addition to their well established roles in the conjugation and biotransformation of xenobiotics, GSTs have emerged as significant regulators of pathways determining cell proliferation and survival and as regulators of ryanodine receptors that are essential for muscle function. This article is part of a Special Issue entitled Cellular functions of glutathione.

Expression patterns of carcinogen detoxifying genes (CYP1A1, GSTP1 & GSTT1) in HNC patients

Carcinogen detoxifying genes may be involved in pathogenesis of head and neck cancer (HNC). CYP1A1 is phase I enzyme that converts carcinogens into water soluble compounds which are easily excreted from body. GSTs constitute phase II detoxification enzymes that recognize these highly electrophilic compounds and detoxify them. Abnormal expression of these genes can potentially lead to cancer initiation. In present study, we analyzed protein expression of these genes in a total of 192 HNC patients and noncancerous healthy control serum samples screened for GSTs specific activity by ELISA. Furthermore, expression of these molecules was also determined in 49 HNC tissues/ adjacent control tissue by immunohistochemistry with specific antibodies. Mean serum GSTs specific activity was found to be 7.7 (+11.5)U/L in HNC patients and 11.4 (+7.5)U/L in controls. Significant decrease (P < 0.05) in GSTs specific activity was observed in HNC patients compared with controls (P < 0.001). Data for immunohistochemistry showed that CYP1A1 and GSTT1 was down expressed whereas GSTP1 was over expressed in HNC tissues compared with adjacent normal control tissues. Results of immunohistochemistry revealed 63 % HNC tissues had weak, 27 % moderate and 10 % strong staining for CYP1A1. For GSTT1, 27 % HNC tissues had no staining, 49 % weak staining, 16 % moderate and 8 % strong staining. Similarly for GSTP1, percentages for weak, moderate and strong staining were 6 %, 12 % and 82 % respectively. These reduced proteins observed in cancer patients highlight a potential breach on DNA repair mechanism when compared with control. Thus altered expression of these detoxifying molecules may collectively contribute to HNC development in Pakistani population.

Association between GSTM1 gene polymorphism in Iranian patients with endometriosis

Endometriosis is defined as a condition in which tissue histologically similar to the endometrium is found outside the uterine cavity. It develops mostly in women of reproductive age. Endometriosis shows a drastically elevated frequency in industrial areas. GSTM1 gene encodes a major detoxification phase enzyme that helps detoxify various xenobiotics. Deficiency in GSTM1 activity is caused by homozygous deletion of GSTM1 and leads to various biological consequences. There are significant interethnic differences in GSTM1 allele frequencies. In this study, the relationship between GSTM1 genotypes and endometriosis in an Iranian population was investigated. The study included 120 patients and 200 healthy volunteers. Genomic DNA was prepared from peripheral blood leukocytes. Genotypes and allele frequencies were determined in patients and healthy controls using polymerase chain reaction (PCR). The GSTM1 null genotype was significantly associated with the increased risk of endometriosis (OR=3.75, 95% confidence interval (CI)=2.42-6.45, P<0.0001). The prevalence of GSTM1-null genotype in the patient group was 72.5%, compared to 40% in the control group. The proportion of GSTM1A/B genotype was higher in controls as compared to cases (20% vs. 2.5%). This study suggests that GSTM1 null genotype is associated with higher risk of endometriosis; these observations, however, requiring further confirmation in a larger multi-ethnic study.

Smoking, the xenobiotic pathway, and clubfoot

BACKGROUND

Isolated clubfoot is a common orthopedic birth defect that affects approximately 135,000 newborns worldwide. It is characterized by ankle equinus, hindfoot varus, and forefoot adductus. Although numerous studies suggest a multifactorial etiology, the specific genetic and environmental components have yet to be delineated. Maternal smoking during pregnancy is the only common environmental factor consistently shown to increase the risk for clubfoot. Moreover, a positive family history of clubfoot, in conjunction with maternal smoking, increases the risk 20-fold. These findings suggest that genetic variation in smoking metabolism (xenobiotic) genes may increase susceptibility to clubfoot. Based on this reasoning, we interrogated eight candidate genes from the xenobiotic metabolism.

METHODS

Twenty-two single-nucleotide polymorphisms and two null alleles in these genes (CYP1A1, CYP1A2, CYP1B1, CYP2A6, EPHX1, NAT2, GSTM1, and GSTT1) were genotyped in a dataset composed of non-Hispanic white and Hispanic multiplex and simplex families.

RESULTS

Only rs1048943/CYP1A1 had significantly altered transmission in the aggregate and multiplex non-Hispanic white datasets (p = 0.003 and p = 0.009, respectively). Perturbation of CYP1A1 can cause an increase in harmful, adduct-forming metabolic intermediates. A significant interaction between EPHX1 and NAT2 was also found (p = 0.007). Importantly, for CYP1A2, significant maternal (p = 0.03; relative risk [RR] = 1.24; 95% confidence interval [CI], 1.04-1.44) and fetal (p = 0.01; RR = 1.33; 95% CI, 1.13-1.54) genotypic effects were identified, suggesting that both maternal and fetal genotypes can negatively impact limb development. No association was found between maternal smoking status and variation in xenobiotic metabolism genes.

CONCLUSION

Together, these results suggest that xenobiotic metabolism genes are unlikely to play a major role in clubfoot; however, perturbation of this pathway may still play a contributory role.

The role and frequency of glutathione s-transferase P1 polymorphism in Iranian patients affected with reflux esophagitis

Reflux esophagitis is a common complication of the gastroesophageal reflux disease. Glutathione s-transferases (GSTs) have important role in the protection of cells from the products of oxidative stress. GSTP1*B allele has a correlation with susceptibility to several diseases. In this case-control study, the role and frequency of GSTP1 polymorphism was evaluated in Iranian patients with erosive reflux esophagitis. Seventy patients with erosive reflux esophagitis and 75 normal individuals were enrolled in this study. The grade of esophagitis was determined via endoscopy. DNA was extracted from venous blood of each subject using the salting out method. GSTP1 genetic polymorphisms were detected using the polymerase chain reaction restriction fragment length polymorphism method. There was a significant difference in GSTP1 genotype frequency between patients and normal groups (P= 0.006). Also, in the patient group, the grade B of esophagitis was significantly associated with variant GSTP1 genotype (P= 0.028). The rate of throat pain symptom was higher in the no-variant group (P < 0.036). The GSTP1*B allele frequency in Iranian normal groups is similar to Orientals. Reflux esophagitis are more commonly found in variant (*B/*B and *A/*B) GSTP1 genotypes. In addition, GSTP1 polymorphism is correlated with a higher grade of esophagitis.

N-Acetyl-cysteine against noise-induced temporary threshold shift in male workers

Previous animal studies showed protective effects of antioxidant medicines against noise-induced hearing loss (NIHL). It is unclear whether antioxidants would protect humans from NIHL. We conducted a study to determine whether N-Acetyl-cysteine (NAC) protected men against noise-induced temporary threshold shift (TTS), and whether subgroups with genetic polymorphisms of glutathione S-transferase (GST) T1 and M1 responded to NAC differently. In this prospective, double-blind, crossover study, 53 male workers were randomly assigned to receive either NAC (1200 mg/day, 14 days) during the first period and placebo during the second period, or placebo during the first period and NAC during the second period. Dosing periods were separated by a washout period of 2 weeks. The hearing threshold changes were determined before and after each dosing period. Pre-shift hearing threshold for high frequencies was 19.1 dB. Daily exposure to noise ranged from 88.4 to 89.4 dB. The noise levels of different frequencies ranged from 80.0 to 89.4 dB with a peak-value at 4 kHz. NAC significantly reduced TTS (p = 0.03). When the participants were grouped by GST M1/T1 genotypes, the NAC effect was only significant among workers with null genotypes in both GSTM1 and GSTT1 (p = 0.004). NAC may prevent noise-induced TTS among occupationally noise-exposed men. The protective effect of NAC was more prominent in subjects with both GSTM1-null and GSTT1-null genotypes. (clinicaltrials.gov Identifier: NCT00552786).

Frequency distribution of GSTM1 and GSTT1 null allele in Pakistani population and risk of disease incidence

Glutathione-S-transferases, GSTM1 and GSTT1 play a significant role in detoxification and bioactivation of a broad range of xenobiotic compounds known to be mutagenic and/or carcinogenic. Deletion polymorphisms of these glutathione transferases (GSTM1 and GSTT1) predispose individuals to environmental carcinogenic compounds. Although a number of studies have shown the relationship between GSTM1 and/or GSTT1 deletion polymorphism and different cancers, these findings cannot be extrapolated to other populations due to intra- and inter-ethnic variability. In order to assess the impact of differential ethnicity on the occurrence of different cancers in local population due to GSTM1, or GSTT1 deletion polymorphism, 111 healthy male and female individuals of different age groups from Southern Punjab, Pakistan were genotyped using a multiplex polymerase chain reaction. From the results it is obvious that null alleles of GSTM1 and GSTT1 genes were found in 45% and 23% individuals, respectively. In 5% of individuals' simultaneous deletion of both GSTM1 and GSTT1 genes were observed. Frequency of GSTM1 null allele is in concordance with those documented for Chinese, Caucasians, Mongolian, and Japanese populations. However, a significantly higher frequency for GSTT1 null was reported in Chinese and Japanese population as compared to Pakistani population. It is the first ever report on frequency of GSTM1 and GSTT1 null allele in Pakistani population which demonstrate the impact of ethnicity and provide basis for future epidemiological and clinical studies.

Interactions between Glutathione-S-Transferase M1, T1 and P1 polymorphisms and smoking, and increased susceptibility to esophageal squamous cell carcinoma

BACKGROUND

A complex of genetic and environmental factors is involved in carcinogenesis of the esophageal squamous cell carcinoma (ESCC). Glutathione-S-Transferases (GSTs) are phase-II enzymes playing role in detoxification of carcinogen electrophiles. Genetic polymorphisms of GSTM1, GSTT1 and GSTP1 in association with some environmental factors and their impact on esophageal cancer susceptibility were assessed in the Iranian population.

METHODS

Genomic DNA of peripheral blood leukocytes from 148 confirmed esophageal cancer cases and 137 healthy individuals as control group was assayed for restriction fragment length polymorphisms in the GSTP1 loci by PCR amplification followed by digestion with Alw26I. Deletion of the GSTM1 and GSTT1 genes was detected by multiplex PCR. A data-mining method based on decision trees was applied to produce a predictive model of interactions between genotypes.

RESULTS

Smoking was independently associated with ESCC (p<0.05, OR: 2.286, 95% CI=1.311-3.983). Smoking along with GSTP1 Val/Val genotype was associated to ESCC (p<0.001, OR: 3.886, 95% CI=1.830-8.251), while non-smokers with GSTP1 Val/Val were significantly more frequent in non-cancerous group. (p=0.007, OR: 0.507, 95% CI=0.309-0.830).

CONCLUSIONS

Data-mining methods are useful tools to map out a scheme for predicting complex relations and combinations of different genotypes. Genotyping analysis of GSTP1 together with assessment of smoking seems to be important in determining the risk of ESCC in the Iranian population.

Association analysis of TNFR2, VDR, A2M, GSTT1, GSTM1, and ACE genes with rheumatoid arthritis in South Asians and Caucasians of East Midlands in the United Kingdom

Genetic associations of TNFR2, VDR (Bsm I and Fok I), A2M, GSTT(1), GSTM(1) and ACE in South Asian and Caucasian patients with rheumatoid arthritis (RA) were assessed in this study. DNA samples from South Asians (134 cases, 149 controls) and Caucasians (137 cases, 150 controls) from the East Midlands of the United Kingdom were genotyped for seven polymorphisms. All cases were rheumatoid-factor positive. Significant genetic associations were observed with TNFR2 R-R (OR = 3.16, CI 1.20-9.26, P < 0.05), A2M 1-1 (OR = 2.09, CI 1.21-3.64, P < 0.05) and GST T(1)null (OR = 1.97, CI 1.07-3.68, P < 0.05) among Caucasian patients. In South Asians, VDR Bsm I B-B genotype (OR = 2.08, CI 1.23-3.52, P < 0.05), A2M 2-2 genotype (OR = 3.99, CI 1.19-17.18, P < 0.05), and GST T(1)null genotype (OR = 2.81, CI 1.40-5.77, P < 0.002) genotypes were associated with RA. In the majority of cases, recessive and multiplicative modes of inheritance explained the observed associations. This study demonstrates that ethnicity affects the genetic associations in RA.

Differential expression of biomarkers in men and women

Lung cancer is one of the most common cancers in the world. While historically, more men than women have died from lung cancer as a result of higher numbers of male smokers, the sex mortality ratio is now showing signs of narrowing. Tumors in women with lung cancer may be slightly different to those in men with lung cancer. This review focuses on biomarkers differentially expressed between female and male patients with lung cancer. There is variation in gene expression between men and women in some genes that encode carcinogen-metabolizing enzymes (CYP1A1, GSTM). Gastrin-releasing peptide (GRP), a bombesin-like peptide, is present in two actively transcribed alleles in women compared with men. Higher prevalence of infection with oncogenic variants human papilloma viruses (HPVs) HPV16 and HPV18 has been suggested in women. A higher frequency of G to T transversion was found in the p53 gene in lung tumors of women. KRAS mutation was found to be more frequent in women with resected non-small cell lung cancer (NSCLC) than in men with resected NSCLC. Epidermal growth factor receptor (EGFR) mutation is more frequently found in lung tumors from women, but the confounding effect of tobacco exposure may explain this difference. Lower levels of ERCC1 and BRCA1 have been reported in women with NSCLC. Lung tumors from women are more likely to express estrogen receptors than those from men. An in silico analysis of transcriptome datasets from lung cancer patients demonstrated that only seven genes (in at least two studies) had significantly different expression patterns in male versus female patients. All of these genes are localized on the sex chromosomes: one on chromosome X and six on chromosome Y. Many areas remain under debate and there are still significant gaps in our understanding, particularly how sex-linked factors relate to lung cancer risk, and to biological and clinical behaviors. Future research into lung cancer needs to address these gender differences more specifically.

Environmental factors promoting bladder cancer

PURPOSE OF REVIEW

To understand the molecular mechanisms of bladder carcinogenesis in relation to environmental carcinogens in order to provide a given population with a preventive value of bladder cancer.

RECENT FINDINGS

Cigarette smoking, aromatic amines contained in dyes, chronic inflammation due to infection such as schistosomiasis, anticancer drugs, drug abuse of analgesic, and radiation are considered as well known risk factors of bladder cancer. Several environmental factors are supposed to be involved in carcinogenesis, cancer progression, and patient's prognosis in bladder cancer. On the basis of the results of recent genetic studies in relation to bladder carcinogenesis, several genetic polymorphisms of detoxification or DNA repair such as N-acetyltransferase 2, glutathione S-transferases, and human 8-oxoguanine DNA glycosylase 1 give us important information in relation to environmental risk factors and ethnic differences for predicting the prognosis of patients with bladder cancer.

SUMMARY

Prevention of environmental carcinogens is important from the viewpoint of the social and clinical problems since elucidation of the correlation between epidemiologic and genetic phenomenon enable us to improve the life expectancy and quality of life of bladder cancer patients.

Investigation of glutathione S-transferase M1 and T1 deletions in lung cancer

Glutathione S-transferases (GSTs) M1 and T1 are known to be polymorphic in humans. Both polymorphisms are due to gene deletions which are responsible for the existence of null genotypes. Previous studies have suggested that GST genotypes may play a role in determining susceptibility to a number of unrelated cancers, including lung cancer. The GSTM1 and GSTT1 polymorphisms were determined by PCR-based analysis in 75 lung cancer patients and 55 controls. The unconditional logistic regression analysis was used to calculate ORs and 95% CI. The frequencies of GSTM1 and GSTT1 null genotypes were 37.3 and 22.7% in lung cancer patients and 27.3 and 16.4% in controls, respectively. When analyzed by histology the GSTM1 null genotype was more prevalent in squamous-cell carcinoma and adenocarcinoma patients. Whereas, GSTT1 null genotype frequency was lower in small-cell lung cancer patients than controls. But these differences were not statistically significant. According to smoking status, null genotype for both gene are associated with an increase in risk for lung cancer. Our results suggest that GSTM1 and GSTT1 polymorphisms may play a role in the development of lung cancer for some histological subtypes and modifies the risk of smoking-related lung cancer.

Genetic polymorphism of glutathione S-transferase M1 and T1 in Delhi population of Northern India

Glutathione S-transferases (GSTs), protect cells from reactive chemical intermediates and oxidative stress. Among different classes of GSTs, GSTM1 (Mu) and GSTT1 (theta) are found to be genetically deleted. Present study was intended to genotype homozygous null distribution of GSTM1 and GSTT1 in healthy individuals of Delhi, located in Northern India. Out of 309 healthy individuals included in this study, we have found genetic deletion in 21% and 27.4%, GSTM1 and GSTT1 genes, respectively. A small proportion (0.7%) population showed deletion of both the genes. The prevalence of the GSTM1(*)0/0 and GSTT1(*)0/0 genotypes varied within India compared to communities in Chinese, Japanese, Korean and Caucasian.

Abnormal liver function associated with occupational exposure to dimethylformamide and glutathioneS-transferase polymorphisms

Dimethylformaide (DMF) is a major solvent predominately used in synthetic leather and resin production. Many human and animal studies have linked the cause of hepatoxicity to DMF. Previously, the authors demonstrated the significant dose-response relationship between abnormal liver function tests and DMF exposure and the interaction with hepatitis B virus (HBV) infection in Taiwanese workers. Because the toxic effect of various chemicals can be modified by metabolic traits, the study also investigated the influence of the glutathione S-transferases (GSTM1 and GSTT1) on the toxic effect of DMF. The average DMF exposure concentration was 23.87 ppm (range 5.2-86.6 ppm) in the high-exposure (>/=5 ppm) group and 2.41 ppm (range 0.9-4.3 ppm) in the low-exposure (<5 ppm) group. There were 13 of 44 (29.6%) abnormal liver function tests (elevations of either glutamate oxaloacetate transaminase (GOT) or glutamate pyruvate transaminase (GPT)) among the high DMF exposure workers, two of 22 (9.1%) abnormal liver function tests among the low DMF exposure workers. Chronic liver disease as determined by ultrasonography was present in seven of 44 (15.9%) high DMF exposure workers, and 0 of 22 (0%) low DMF exposure workers. There were 11 of 34 (32.4%) abnormal liver function tests among the GSTT1 null genotype workers, and four of 32 (12.5%) abnormal liver function tests among the GSTT1-positive genotype workers. Compared with the low DMF exposure workers, the adjusted odds ratio and 95% confidence intervals for abnormal liver function tests was 6.78 (0.94-48.7) for the high DMF exposure workers. Compared with the GSTT1-positive genotype workers, the adjusted odds ratio and 95% confidence intervals for abnormal liver function tests was 4.41 (1.15-16.9) for the GSTT1 null genotype workers. Compared with the low DMF group with GSTT1-positive genotype workers, the odds ratio (adjusted for HBV status) of abnormal liver function test was 12.38, 95% CI=(1.04-146.9) for the high DMF group with GSTT1 null genotype workers. This study indicates that abnormal liver function and chronic liver disease are associated with DMF exposure, and there are more than multiplicative interaction effects on abnormal liver function tests between the DMF exposure and the GSTT1 genotype.

Glutathione S-transferase M1 (GSTM1) polymorphisms and lung cancer: a literature-based systematic HuGE review and meta-analysis

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

Genetic polymorphisms of human cytosol glutathione S-transferases and prostate cancer

Glutathione S-transferases (GSTs) are involved in the metabolism of a wide range of carcinogenic chemicals. In humans, cytosol GSTs are divided into eight classes: alpha (GSTA), mu (GSTM), pi (GSTP), theta (GSTT), tau (GSTZ), sigma (GSTS), omicron (GSTO) and kappa (GSTK). The allelic polymorphism of these enzymes is associated with variations in enzyme activity; hence, it may affect the concentration of activated carcinogenic chemicals in the body. In addition to the metabolism of chemical carcinogens, GSTs metabolize steroid hormones, compounds in the diet and other agents potentially involved in prostate carcinogenesis. Three genetic polymorphisms of GSTs, GSTM1*0 (null), GSTT1*0 (null) and GSTP1 A313G, have been well documented. No consistent associations between GSTM1, GSTT1 or GSTP1 genotypes and prostate cancer have been observed. Recent meta-analysis reports show that these polymorphisms of GSTM1, GSTT1 and GSTP1 are unlikely to be major determinants of susceptibility to prostate cancer.

From human genetics and genomics to pharmacogenetics and pharmacogenomics: past lessons, future directions

A brief history of human genetics and genomics is provided, comparing recent progress in those fields with that in pharmacogenetics and pharmacogenomics, which are subsets of genetics and genomics, respectively. Sequencing of the entire human genome, the mapping of common haplotypes of single-nucleotide polymorphisms (SNPs), and cost-effective genotyping technologies leading to genome-wide association (GWA) studies - have combined convincingly in the past several years to demonstrate the requirements needed to separate true associations from the plethora of false positives. While research in human genetics has moved from monogenic to oligogenic to complex diseases, its pharmacogenetics branch has followed, usually a few years behind. The continuous discoveries, even today, of new surprises about our genome cause us to question reviews declaring that "personalized medicine is almost here" or that "individualized drug therapy will soon be a reality." As summarized herein, numerous reasons exist to show that an "unequivocal genotype" or even an "unequivocal phenotype" is virtually impossible to achieve in current limited-size studies of human populations. This problem (of insufficiently stringent criteria) leads to a decrease in statistical power and, consequently, equivocal interpretation of most genotype-phenotype association studies. It remains unclear whether personalized medicine or individualized drug therapy will ever be achievable by means of DNA testing alone.

Association of the diplotype configuration at the N-acetyltransferase 2 gene with adverse events with co-trimoxazole in Japanese patients with systemic lupus erythematosus

Although co-trimoxazole (trimethoprim-sulphamethoxazole) is an effective drug for prophylaxis against and treatment of Pneumocystis pneumonia, patients often experience adverse events with this combination, even at prophylactic doses. With the aim being to achieve individual optimization of co-trimoxazole therapy in patients with systemic lupus erythematosus (SLE), we investigated genetic polymorphisms in the NAT2 gene (which encodes the metabolizing enzyme of sulphamethoxazole). Of 166 patients with SLE, 54 patients who were hospitalized and who received prophylactic doses of co-trimoxazole were included in the cohort study. Adverse events occurred in 18 patients; only two experienced severe adverse events that lead to discontinuation of the drug. These two patients and three additional ones with severe adverse events (from other institutions) were added to form a cohort sample and were analyzed in a case-control study. Genotype was determined using TaqMan methods, and haplotype was inferred using the maximum-likelihood method. In the cohort study, adverse events occurred more frequently in those without the NAT2*4 haplotype (5/7 [71.4%]) than in those with at least one NAT2*4 haplotype (13/47 [27.7%]; P = 0.034; relative risk = 2.58, 95% confidence interval = 1.34-4.99). In the case-control study the proportion of patients without NAT2*4 was significantly higher among those with severe adverse events (3/5 [60%]) than those without severe adverse events (6/52 [11.5%]; P = 0.024; odds ratio = 11.5, 95% confidence interval = 1.59-73.39). We conclude that lack of NAT2*4 haplotype is associated with adverse events with co-trimoxazole in Japanese patients with SLE.

Genetic polymorphisms and esophageal cancer risk

The aim of this paper is to review and evaluate, in a comprehensive manner, the published data regarding the contribution of genetic polymorphisms to risk of esophageal cancer, including squamous cell carcinoma (SCC) and adenocarcinoma, in humans. All relevant studies available in MEDLINE and published before February 2007 were identified. Studies carried out in humans and that compared esophageal cancer patients with at least 1 standard control group were considered for analysis. One-hundred studies and 3 meta-analyses were identified. Eighty (80%) studies were conducted in Asian countries, particularly China including Taiwan (60 (60%) studies). The most intensively examined genes were those encoding carcinogen metabolic enzymes. The most widely studied gene was GSTM1 (15 studies), followed by ALDH2 (11 studies). ALDH2, MTHFR C677T, CYP1A1 Ile/Val, CYP1A1MspI, CYP2E1, GSTP1, GSTM1 and GSTT1 were examined by meta-analyses and significant relations were found between ALDH2*1*2 and the CYP1A1 Val allele and increased risk of esophageal cancer. In addition, increased risk of esophageal SCC was consistently associated with the ADH2*1*2 and the p53 codon 72 Pro/Pro genotypes. Cohort studies that simultaneously consider multiple genetic and environmental factors possibly involved in esophageal carcinogenesis are needed to ascertain not only the relative contribution of these factors to tumor development but also the contributions of their putative interactions.

Cloning, sequence analysis and identification of a nonsense mutation-mediated mRNA decay of porcine GSTM2 gene

The glutathione S-transferase mu 2 gene (GSTM2) encodes a GST functioning in the elimination of electrophilic compounds and the regulation of cell growth. In this study, the sequence of porcine GSTM2 gene that contains the complete sequence encoding a protein of 218 amino acids was cloned. The deduced amino acid sequence shared 76%, 78% and 76% identity with that of human, mouse and rat, respectively. mRNA expression analysis showed that the porcine GSTM2 gene was expressed at a high level in liver and testis, at a medium level in longissimus dorsi muscle, adipose tissue, spleen and lung, at a low level in kidney, and at a very low level in heart and embryo. A nonsense mutation (CGA-->TGA) resulted from C27T substitution in the fifth exon to produce a premature translation termination codon was identified, and it was discovered that nonsense-mediated mRNA decay might have an effect on the regulation of porcine GSTM2 gene expression. This polymorphism was analyzed in Large White, Landrace, Meishan and Qingping pig populations using the Taq I-polymerase chain reaction-restriction fragment length polymorphism method. The result showed that allele C had a higher frequency than allele T in each population.

GSTM1 and GSTT1 polymorphisms as modifiers of age at diagnosis of hereditary nonpolyposis colorectal cancer (HNPCC) in a homogeneous cohort of individuals carrying a single predisposing mutation

The variability in phenotype that occurs for so-called 'single-gene disorders' may be because of germline alterations in numerous primary and "modifier" genes. Within HNPCC families harbouring the same primary predisposing mutation, differences exist in the site of cancer, age of onset of disease symptoms and, consequently, survival until diagnosis of disease. The current study investigated a cohort of 129 individuals, from 13 different families, who harbour the identical nonsense mutation (C1528T) in the hMLH1 gene, predisposing them primarily to Lynch I syndrome. This cohort was screened for previously described polymorphisms in the glutathione-S-transferase genes, viz. GSTT1 and GSTM1. Male null carriers for both GSTT1 and GSTM1 were approximately three times more at risk of developing cancer at an earlier age when compared to non-null males. This work, particularly because of the relatively large "homogeneous" primary mutation cohort, provides evidence that genotypic changes distinct from the primary 'HNPCC-causing' mutation, influence the survival period until diagnosis of disease. It provides an impetus for expanding the study to include a wider range of candidate modifier genes. Such work may potentially lead to the development of individualised interval screening regimens for individuals with varying modifier genotypes--an attractive option in a resource-poor country.

Genetic polymorphisms in glutathione S-transferases T1, M1 and P1 and susceptibility to reflux esophagitis

Recent studies indicate that the prevalence of reflux esophagitis (RE) in China is increasing. RE is one of the most common esophageal complications associated with gastroesophageal reflux disease (GERD) and RE-Barrett's esophagus-esophageal adenocarcinoma (EAC) sequence has been considered as an histogenesis model for EAC in Western countries. RE is only present in a subset of patients with GERD, suggesting an altered susceptibility to RE may exist in these GERD individuals. However, the genetic changes related with high susceptibility to RE is largely unknown. The polymorphisms in glutathione S-transferases (GSTs) T1, M1 and P1 have been reported with high susceptibity to esophageal cancer in Chinese people. The present case-control study was thus undertaken to characterize the genetic polymorphisms of GSTs and their correlation with susceptibility to RE. One hundred and nine patients with RE, 97 patients with nonerosive reflux disease (NERD) and 97 normal controls were recruited in this study. All the subjects were from Beijing, China, and received endoscopic examination and questionnaires for RE. Genomic DNA was extracted from the lymphocytes of peripheral blood for each subject. Genotypes of the GSTM1 and GSTT1 genes were analyzed by a multiplex PCR method. A-->G polymorphism of codon 104 of the GSTP1 gene was detected using PCR-based restriction fragment length polymorphisms (RFLP). The variant GSTP1 genotypes (*A/*Bomicron*B/*B) was found with a high frequency in the case with RE (40%), and followed by NERD (25%) and normal control (22%). The differences were statistically significant (P < 0.05). The risk for RE increased 2.42-fold [odds ratio (OR); 95% confidence interval (95% CI), 2.42 (1.22-4.80)] in the subjects with variant GSTP1 genotype. The subjects with positive variant GSTP1 genotypes and negative H. pylori infection showed increasing tendency for risk of RE [OR (95% CI), 2.67 (1.06-6.70)]. However, the subjects with GSTT1 and GSTM1 polymorphisms did not show any correlation with high risk for RE or NERD. No significant interactions were identified between the variant GSTs and cigarette smoking, or alcohol drinking and subtype of RE. The present result suggests that GSTP1 genetic polymorphism may be one of the high susceptibility factors involved in the mechanisms of RE. H. pylori infection may play a protective role against RE.

Genetic polymorphisms in CYP1A1 and GSTM1 predispose humans to PCBs/PCDFs-induced skin lesions

INTRODUCTION

Polychlorinated biphenyls (PCBs) and dibenzofurans (PCDFs) are ubiquitous persistent pollutants in humans. Whether people with different genotypes are with different susceptibility to these chemicals are unknown. In a group of people highly exposed to PCBs/PCDFs, we tested the hypothesis that genotypic polymorphisms affected susceptibility for development of skin manifestations.

METHODS

In 1979, approximately 2000 people in central Taiwan ingested cooking oil contaminated with PCBs/PCDFs. Skin disorder such as chloracne, abnormal nail, hyperkeratosis and skin allergy were found in PCBs/PCDFs exposed group. We recruited exposed and community background exposure subjects for blood testing and telephone-interview. Single nucleotide polymorphisms, AhR Arg554Lys, CYP1A1 Ile462Val, CYP1A1 T6235C, and GSTM1/T1 deletion, were determined. Occurrence of skin manifestations was compared among people with different genotypes while stratified by PCB exposure levels by logistic regression.

RESULTS

Data on exposure, medical history, and genotypes were obtained from 393 exposed and 181 background exposure groups. Skin manifestations including chloracne, allergy, abnormal nail, and hyperkeratosis were more prevalent in exposed people in a dose-related manner. Among highly exposed individuals, combined CYP1A1-MspI mutant genotype and GSTM1-null genotype were associated with increased risk of chloracne (odds ratio 2.8, 95% confidence interval 1.1-7.6). Among intermediately exposed individuals, GSTM1 null genotype was associated with skin allergy. AhR Arg554Lys genotype and GSTT1 null genotype were not related to susceptibility to skin manifestations in PCB/PCDF-exposed population.

CONCLUSION

CYP1A1 and GSTM1 genotypic polymorphisms might be related to the susceptibility to PCB/PCDF-induced skin manifestations.

Towards a lung adenocarcinoma proteome map: Studies with SP-C/c-raf transgenic mice

We report mapping of proteins of adenocarcinomas of the lung as a result of overexpression of the oncogenically activated N-terminal deletion mutant c-raf-1 BxB through usage of the human SP-C promotor. Proteins from non-transgenic controls and tumors were extracted with a lysis buffer containing 5 mol/L urea, 2 mol/L thiourea, 40 mmol/L Tris, 4% CHAPS, 100 mmol/L DTT, 0.5% BioLyte 3-10, separated by 2-DE and studied by image analysis. On average, 300-600 protein spots per gel were excised and analyzed by MALDI-TOF and -TOF/TOF MS. More than 1000 of the CBB-stained proteins were identified and traced back to 100 different gene products, including many of their isoforms. We observed significant changes in the expression of proteins involved in cellular defense or glycolysis, and this included glutathione S-transferase, peroxiredoxin 6, and alpha-enolase, among others. Proteins associated with lung tumor growth and/or metastasis, i.e., lung carbonyl reductase, differed in expression, as did tumor-associated expression of cell adhesion and membrane-bound proteins such as vinculin. This map provides valuable insight into expression of pulmonary proteins associated with lung adenocarcinomas, some of which may be of utility as diagnostic markers in clinical trials.