Aflatoxin B1 (AFB1) is a potent hepatocarcinogen in experimental animals and a hazard to human health in several parts of the world. Implementation of rational intervention plans requires understanding of aspects of the roles of individual chemical steps involved in its disposition. AFB1 is activated to AFB1 exo-8,9-epoxide primarily by cytochrome P450 (P450) enzymes, particularly P450 3A4. However, P450 3A4 and other P450s also oxidize AFB1 to less dangerous products. The exo-epoxide is unstable in H2O (t1/2 1 s at 25 degreesC, k=0.6 s-1) and the diol product undergoes base-catalyzed rearrangement to a dialdehyde that reacts with protein lysine residues. AFB1 exo-8, 9-epoxide reacts with DNA to give adducts in high yield (>98%). This interaction is characterized by a Kd of approximately 1.4 mM, intercalation between base pairs, and rapid reaction with the guanyl N7 atom (k approximately 40 s-1). A proton field on the periphery of DNA is postulated to catalyze hydrolysis and also conjugation. Rat and especially human epoxide hydrolase show very little rate acceleration of hydrolysis of AFB1 exo- or endo-8,9-epoxide. However, glutathione transferases (GSTs) can catalyze AFB1 exo-8,9-epoxide conjugation. Kinetic analysis indicates a range of ratios of kcat/Kd varying from 10 to 1700 s-1 M-1, with the polymorphic GST M1-1 having the highest activity of the human GSTs. Studies with human hepatocytes indicate a major role for GST M1-1 in AFB1 conjugation and that the model chemoprotective agent oltipraz can act by both inducing GSTs and inhibiting P450s.

OBJECTIVE

Glutathione S-transferases (GSTs) are involved in the detoxification of many potential carcinogens and appear to play a critical role in the protection from the effects of carcinogens. The contribution of glutathione S-transferases M1 and T1 genotypes to susceptibility to the risk of gastric cancer and their interaction with cigarette smoking are still unclear. The aim of this study was to determine whether there was any relationship between genetic polymorphisms of GSTT1 and GSTT1 and gastric cancer.

METHODS

A population based case-control study was carried out in a high-risk area, Changle County, Fujian Province, China. The epidemiological data were collected by a standard questionnaire and blood samples were obtained from 95 incidence gastric cancer cases and 94 healthy controls. A polymerase chain reaction method was used to detect the presence or absence of the GSTT1 and GSTT1 genes in genomic DNA. Logistic regression model was employed in the data analysis.

RESULTS

An increase in risk for gastric cancer was found among carriers of GSTT1 null genotype. The adjusted odds ratio (OR) was 2.63 95% Confidence Interval (95% CI) 1.17-5.88, after controlling for age, gender, cigarette smoking, alcohol drinking, and fish sauce intake. The frequency of GSTT1 null genotype in cancer cases (43.16%) was not significantly different from that in controls (50.00%). However, the risk for gastric cancer in those with GSTT1 null and GSTT1 non-null genotype was significantly higher than in those with both GSTT1 and GSTT1 non-null genotype (OR = 2.77, 95% CI 1.15-6.77). Compared with those subjects who never smoked and had normal GSTT1 genotype, ORs were 1.60 (95% CI:0.62-4.19) for never smokers with GSTT1 null type, 2.33 (95% CI 0.88-6.28) for smokers with normal GSTT1, and 8.06 (95% CI 2.83-23.67) for smokers with GSTT1 null type.

CONCLUSIONS

GSTT1 gene polymorphisms may be associated with genetic susceptibility of stomach cancer and may modulate tobacco-related carcinogenesis of gastric cancer.

The isothiocyanate sulforaphane (SF) is thought to be a potential chemoprotective agent. Its effects on Phase I and Phase II enzymes of carcinogen metabolism in primary cultures of rat and human hepatocytes have been investigated. Northern blot analyses of rat hepatocytes showed a dose-dependent induction of mRNAs for rat glutathione S-transferases (rGSTs) A1/A2 and P1 but not M1. This was associated with enhanced levels of not only rGSTA1, A2, A4, A5, and P1 but also of rGSTs M1 and M2. On the other hand, the enzyme activities in rat hepatocytes associated with cytochromes P-450 (CYPs) 1A1 and 2B1/2, namely ethoxyresorufin-O-deethylase and pentoxyresorufin-O-dealkylase, respectively, were decreased in a dose-dependent manner. In SF-treated human hepatocytes, hGSTA1/2 but not hGSTM1 mRNAs were induced, and the expression of CYP1A2 was unaffected, whereas the expression of CYP3A4, the major CYP in human liver, was markedly decreased at both mRNA and activity levels. These observations demonstrate that in intact human and rat hepatocytes, SF may both induce a number of GSTs and cause enzyme inhibition of some but not all CYPs and, in the case of CYP3A4, inhibit both its enzyme activity and its expression.

The effect of genetic polymorphisms for glutathione S-transferase ( GST) M1, GSTT1, GSTP1-1( GSTP1), cytochrome P450 2E1 ( CYP2E1) and aldehyde dehydrogenase 2 ( ALDH2) on the risk of hepatocellular carcinoma (HCC) was observed in 78 Japanese patients with HCC and 138 non-cancer hospital controls. We found a positive association between cumulative amounts of alcohol consumption >>/=600,000 ml in a lifetime) and the risk of HCC (OR=4.52, 95% CI 2.39-8.55). However, cigarette smoking was not significantly related to the risk of HCC (OR=1.23, 95% CI 0.57-2.68). The allelic frequencies of GSTM1, GSTT1, GSTP1, CYP2E1and ALDH2of HCC patients were not significantly different from those of controls when odds ratios were only adjusted for age and gender except for any 2 alleles of ALDH2in drinkers (OR=2.53, 95% CI 1.21-5.31). However, the frequency of any C2 alleles of CYP2E1and any 2 alleles of ALDH2were significantly higher than those of controls (OR=5.77, 95% CI 1.24-27.39, OR=9.77, 95% CI 1.63-58.60) when covariates including viremia were selected by using stepwise logistic regression analysis. We conclude that habitual alcohol drinking is likely to lead to an increased risk of HCC, and any C2alleles of CYP2E1as well as any two alleles of ALDH2were also associated with an increased risk of HCC.

Both genetic and environmental factors are involved in the development of cancer. Oral cavity cancer has been reported to be epidemiologically associated with tobacco and alcohol consumption. We examined genetic polymorphisms of the glutathione-S-transferase (GST) M1/T1, cytochrome P-450 (CYP) 1A1/2E1 and aldehyde dehydrogenase 2 (ALDH2) genes in 92 Japanese patients with oral cavity cancer and 147 unrelated non-cancer Japanese controls. There was a significant association between cigarette smoking and cancer risk but no significant association between alcohol consumption and cancer risk. The frequency of the GSTM1 null genotype was significantly higher in cancers (58.7%) compared with controls (46. 3%). However, there were no significant differences between controls and patients with oral cavity cancer in the polymorphisms of the GSTT1, CYP1A1, CYP2E1 and ALDH2 genes. From statistical evaluation on various combinations of genotypes, we did not observe any gene combinations associated with cancer risk. There were also no genetic polymorphisms associated with increased risk of oral cavity cancer among smokers and drinkers. These results imply that the GSTM1 null genotype has a weak correlation, but another 4 genetic polymorphisms are unlikely to be associated, with oral cavity cancer among Japanese.

The macrophage, one of the several key immune cell types, is believed to be involved in tumorigenesis. However, the mechanism of macrophages promoting tumor progression is largely unknown.

The differentially secreted proteins of M1 and M2 macrophages were analyzed by mass spectrometry. We performed GST pull-down assay for the identification of cell-membrane receptors that interact with chitinase 3-like protein 1 (CHI3L1) protein. The mouse model was used to validate the function of CHI3L1 in cancer metastasis in vivo. Protein phosphorylation and gene expression were performed to study the signaling pathway activation of cancer cells after CHI3L1 treatment.

M2 macrophage-secreted CHI3L1 promoted the metastasis of gastric and breast cancer cells in vitro and in vivo. The CHI3L1 protein functioned by interacting with interleukin-13 receptor α2 chain (IL-13Rα2) molecules on the plasma membranes of cancer cells. Activation of IL-13Rα2 by CHI3L1 triggered the activation of the mitogen-activated protein kinase signaling pathway, leading to the upregulated expression of matrix metalloproteinase genes, which promoted tumor metastasis. The results of this study indicated that the level of CHI3L1 protein in the sera of patients with gastric or breast cancer was significantly elevated compared with those of healthy donors.

Our study revealed a novel aspect of macrophages with respect to cancer metastasis and showed that CHI3L1 could be a marker of metastatic gastric and breast cancer in patients.

Genetic susceptibility to the development of chronic obstructive pulmonary disease (COPD) might depend on variation in the activities of enzymes that detoxify cigarette smoke products, such as microsomal epoxide hydrolase (mEPHX) and glutathione S-transferase (GST). It was investigated whether polymorphisms in these genes had any association with susceptibility to COPD and COPD severity. The genotypes of 184 patients with COPD and 212 control subjects were determined by polymerase chain reaction followed by restriction fragment length polymorphism analysis of the mEPHX, GSTM1, GSTT1 and GSTP1 genes. All subjects were smokers or exsmokers. The proportion of GSTM1-null genotypes was significantly higher in patients with COPD than in control subjects (61.4 versus 42.5%). No differences were observed in the frequency of polymorphic genotypes for mEPHX, GSTT1 and GSTP1. During combined analysis of genetic polymorphisms for mEPHX, GSTM1 and GSTP1, it was found that there are strong indicators for susceptibility to COPD (genotype combination with at least one mutant mEPHX exon-3 allele (histidine 113), GSTM1 null and homozygous for the GSTPI isoleucine 105 allele). The frequencies of homozygous mutant alleles of mEPHX exon 3 and the GSTMI-null genotype were significantly higher in patients with severe COPD (forced expiratory volume in one second of <35% of the predicted value). It is proposed that the combination of genetic variants including at least one mutant microsomal epoxide hydrolase exon-3 allele and glutathione S-transferase M1-null and homozygous isoleucine 105 glutathione S-transferase P1 genotypes are significant indicators of susceptibility to chronic obstructive pulmonary disease in the Taiwanese population. In addition, the homozygous variant of microsomal epoxide hydrolase exon 3 and the glutathione S-transferase M1-null genotype are independent risk factors for developing severe chronic obstructive pulmonary disease.

Both genetic and environmental factors are involved in the development of cancer; some phase I and II enzymes involved in the metabolism of carcinogens are polymorphic in genotypes. This case-control study focused on the interactions between oral cancer risk factors and genetic polymorphisms of cytochrome P-450 (CYP) 2E1 and glutathione S-transferase (GST) M1 and GSTT1. A total of 41 male oral cancer cases was recruited from National Taiwan University Hospital, and 123 healthy controls frequency-matched on ethnicity, sex, and age were recruited from residents living in Taipei City and Taipei County. History of cigarette smoking, alcohol drinking, and betel quid chewing was obtained through a standardized questionnaire interview, and genotypes of CYP2E1, GSTM1, and GSTT1 were determined by PCR. Cigarette smoking, alcohol drinking, and betel quid chewing were significantly associated with the risk of oral cancer in a dose-response relationship. All betel quid chewers smoked cigarettes in both the case and control groups. In the multiple logistic regression analysis, those who had null genotypes of GSTM1 and/or GSTT1 had an increased oral cancer risk compared with those who had non-null genotypes of both GSTM1 and GSTT1, showing a multivariate-adjusted odds ratio (OR) of 4.6 with a 95% confidence interval (CI) of 0.9-23.7 (P = 0.08). The CYP2E1 c1/c2 and c2/c2 genotypes were associated with a significantly increased oral cancer risk compared with the c1/c1 genotype among those who did not chew betel quid (OR, 4.7; 95% CI, 1.1-20.2), but not among betel quid chewers. Habitual alcohol drinking was associated with a significantly increased oral cancer risk, showing an OR of 3.0 (95% CI, 1.1-8.8). These results implied that there are gene-gene and gene-environment interactions in the development of oral cancer.

The chemoprotective effect of cruciferous vegetables is due to their high glucosinolate content and the capacity of glucosinolate metabolites, such as isothiocyanates (ITC) and indoles, to modulate biotransformation enzyme systems (e.g., cytochromes P450 and conjugating enzymes). Data from molecular epidemiologic studies suggest that genetic and associated functional variations in biotransformation enzymes, particularly glutathione S-transferase (GST)M1 and GSTT1, which metabolize ITC, alter cancer risk in response to cruciferous vegetable exposure. Moreover, genetic polymorphisms in receptors and transcription factors that interact with these compounds may further contribute to variation in response to cruciferous vegetable intake. This review outlines the metabolism and mechanisms of action of cruciferous vegetable constituents, discusses the recent human studies testing effects of cruciferous vegetables on biotransformation systems and summarizes the epidemiologic and experimental evidence for an effect of genetic polymorphisms in these enzymes on response to cruciferous vegetable intake. Taken together, genetic differences in biotransformation enzymes and the factors that regulate them, as well as variation in glucosinolate content of cruciferous vegetables and the methods used to prepare these foods underscore the multiple layers of complexity that affect the study of gene-diet interactions and cancer risk in humans.

Glutathione S-transferases (GSTs) are known to take part in detoxification of many potentially carcinogenic compounds. Therefore, polymorphisms of the GST genes have been considered as potentially important modifiers of individual risk of environmentally induced cancers. The association between lack of glutathione S-transferase M1 gene (GSTM1 null genotype) and susceptibility to smoking-related lung cancer has been actively studied, with contradictory results. In contrast, little is known about the more recently found polymorphisms in GSTM3, GSTP1 and GSTT1 genes with respect to individual responses to environmental exposures. In this study, we determined the genotype distribution of all these genes, and their combinations, among 208 Finnish lung cancer patients and 294 population controls. None of the genotypes studied had a statistically significant effect on lung cancer risk, when studied separately. However, a significant association was observed for concurrent lack of the GSTM1 and GSTT1 genes and susceptibility to squamous cell carcinoma. For that cell type, the risk was more than 2-fold when compared with that of individuals having other genotype combinations (OR = 2.3; 95% CI = 1.0-5.3; p = 0.05). Moreover, the risk was mostly attributable to patients with smoking history of 40 pack-years or less (OR = 2.9; 95% CI = 1.1-7.7; p = 0.03). In contrast, this genotype combination did not affect the risk for other histological types of lung cancer, and the other genotype combinations had no effects on individual susceptibility to this malignancy. The overall role of GST polymorphisms in modifying the lung cancer risk may therefore be more limited than has been so far anticipated.

BACKGROUND

Tumor necrosis factor (TNF) mediates a spectrum of airway inflammatory responses, including those to air pollutants, and is an asthma candidate gene. One TNF promoter variant (G-308A) affects expression of TNF and has been associated with inflammatory diseases; however, studies of asthma have been inconsistent. Because ozone produces oxidative stress, increased airway TNF, and inflammation, the associations of the -308 TNF polymorphism with asthma may vary by ozone exposure and variants of oxidant defense genes glutathione-S-transferase (GST) M1 and GSTP1.

OBJECTIVE

To investigate the association of TNF G-308A with asthma and wheezing and to determine whether these associations vary with ozone exposure and GSTM1 and GSTP1 genotype.

METHODS

We studied associations of TNF-308 genotype with lifetime and current wheezing and asthma among 3,699 children in the Children's Health Study. We examined differences in associations with community ozone and by GSTM1 null and GSTP1 105 Ile/Val (A105G) genotype.

RESULTS

Children with TNF-308 GG had decreased risk of asthma (odds ratio, 0.8; 95% confidence interval, 0.7-0.9) and lifetime wheezing (odds ratio, 0.8; 95% confidence interval, 0.7-0.9). The protective effects of GG genotype on wheezing outcomes were of greater magnitude in lower compared with higher ozone communities. These findings were replicated in the two cohorts of fourth-grade children recruited in 1993 and 1996. The reduction of the protective effect from the -308 GG genotype with higher ozone exposure was most marked in the GSTM1 null and GSTP1 Ile/Ile groups.

CONCLUSIONS

The TNF-308 GG genotype may have a protective role in asthma pathogenesis, depending on airway oxidative stress levels.

Tobacco use is causally associated with head and neck squamous cell cancer (HNSCC). Here, we present the results of a case-control study that investigated the effects that the genetic variants of the cytochrome (CYP)1A1, CYP1B1, glutathione-S-transferase (GST)M1, GSTT1, and GSTP1 genes have on modifying the risk of smoking-related HNSCC. Allelisms of the CYP1A1, GSTT1, GSTM1, and GSTT1 genes alone were not associated with an increased risk. CYP1B1 codon 432 polymorphism was found to be a putative susceptibility factor in smoking-related HNSCC. The frequency of CYP1B1 polymorphism was significantly higher (P < 0.001) in the group of smoking cases when compared with smoking controls. Additionally, an odds ratio (OR) of 4.53 (2.62-7.98) was discovered when investigating smoking and nonsmoking cases for the susceptible genotype CYP1B1*2/*2, when compared with the presence of the genotype wild type. In combination with polymorphic variants of the GST genes, a synergistic-effect OR was observed. The calculated OR for the combined genotype CYP1B1*2/*2 and GSTM1*2/*2 was 12.8 (4.09-49.7). The calculated OR for the combined genotype was 13.4 (2.92-97.7) for CYP1B1*2/*2 and GSTT1*2/*2, and 24.1 (9.36-70.5) for the combination of CYP1B1*2/*2 and GSTT1-expressors. The impact of the polymorphic variants of the CYP1B1 gene on HNSCC risk is reflected by the strong association with the frequency of somatic mutations of the p53 gene. Smokers with susceptible genotype CYP1B1*2/*2 were 20 times more likely to show evidence of p53 mutations than were those with CYP1B1 wild type. Combined genotype analysis of CYP1B1 and GSTM1 or GSTT1 revealed interactive effects on the occurrence of p53 gene mutations. The results of the present study indicate that polymorphic variants of CYP1B1 relate significantly to the individual susceptibility of smokers to HNSCC.

Nicotinamide adenine dinucleotide (phosphate) reduced:quinone oxidoreductase (NQO1) and glutathione S-transferase (GST) M1 are phase II enzymes important in response to oxidative stress, such as occurs during exposure to ozone. We examined the relationship between functionally significant polymorphisms in NQO1 (Pro187Ser) and GSTM1 (homozygous deletion) and asthma risk in children with high lifetime exposure to ozone. We enrolled children with asthma from the allergy referral clinic at a public pediatric hospital in Mexico City, together with their parents. We assayed for the Pro187Ser polymorphism in NQO1 using a polymerase chain reaction-restriction fragment length polymorphism assay and for the presence of GSTM1 by polymerase chain reaction among 218 case-parent triads. We did not find strong evidence of an association between NQO1 genotype alone and asthma risk. However, among subjects with homozygous deletion of GSTM1, carriers of a serine allele were at significantly reduced risk of asthma compared with Pro/Pro homozygotes (relative risk = 0.4; 95% confidence interval, 0.2-0.8). The p value for difference in relative risk for NQO1 by GSTM1 genotype = 0.013. These data are consistent with a protective effect of the NQO1 Ser allele in this population of GSTM1-null children with high ozone exposure.

OBJECTIVE

The purpose of this research was to investigate the relationship between glutathione S-transferase (GST) polymorphisms and survival, and chemotherapy-related toxicity in 278 glioma patients.

METHODS

We determined genetic variants for GSTM1, GSTT1, and GSTP1 enzymes by PCR and restriction fragment length polymorphisms. We conducted Kaplan-Meier and Cox-proportional hazard analyses to examine whether the GST polymorphisms are related to overall survival, and logistic regression analysis to explore whether the GST polymorphisms are associated with toxicity.

RESULTS

For patients with anaplastic astrocytoma, anaplastic oligodendroglioma, anaplastic oligoastrocytoma, and anaplastic ependymoma (n = 78), patients with GSTP1*A/*A-M1 null genotype survived longer than did the rest of the group (median survival "not achieved," and 41 months, respectively; P = 0.06). Among patients treated with nitrosoureas (n = 108), those with GSTP1*A/*A and GSTM1 null genotype were 5.7 times (95% confidence interval, 0.9-37.4) more likely to experience an adverse event secondary to chemotherapy, compared with the others.

CONCLUSIONS

In patients with anaplastic astrocytoma, anaplastic oligodendroglioma, and anaplastic oligoastrocytoma, combination of germ-line GSTP1*A/*A and GSTM1 null genotype confers a survival advantage. Patients with this genotype also have an increased risk of adverse events secondary to chemotherapy that primarily comprised nitrosourea alkylating agents.

BACKGROUND

Epidemiologic findings of tobacco and alcohol use in relation to gastric cancer are inconsistent. Well-designed prospective studies examining their relationship are sparse.

METHODS

The association between cigarette smoking/alcohol intake and gastric cancer risk was examined in a population-based prospective cohort of 18,244 middle-aged and older men in Shanghai, China, who were enrolled in the study during 1986-1989. After up to 20 years of follow-up, 391 incident gastric cancer cases were identified. Cox proportional hazards regression models were used to estimate hazard ratios (HR) and corresponding 95% confidence intervals (95% CI).

RESULTS

Ever smokers experienced a statistically significant increased risk of gastric cancer (HR, 1.59; 95% CI, 1.27-1.99) compared with nonsmokers after adjustment for alcohol intake and other confounders. Among nondrinkers, smokers experienced 80% increased risk of gastric cancer (HR, 1.81; 95% CI,1.36, 2.41). Conversely, heavy drinkers experienced a statistically significant increase in risk of gastric cancer (HR, 1.46; 95% CI, 1.05-2.04) among all subjects and a statistically nonsignificant 80% increased risk among never smokers. Further adjustment for Helicobacter pylori serology, serum levels of beta-carotene and vitamin C, and urinary level of total isothiocyanates in combination with glutathione S-transferase (GST) M1 and GSTT1 genotypes did not materially change the associations between smoking/alcohol consumption and gastric cancer risk.

CONCLUSIONS

These results suggest that cigarette smoking and alcohol consumption may exert independent effects on the development of gastric cancer in this high-risk population.

CONCLUSIONS

Modification of these lifestyle choices may reduce the incidence of gastric cancer.

Individual vulnerability to drug-induced liver injury (DILI) might result from deficiencies in the detoxification process, which determines the level of exposure to the reactive metabolite. We evaluated whether a genetically determined reduction in the ability to detoxify electrophilic compounds, such as that expected among individuals with glutathione S-transferase (GST) null genotypes, might play a role in determining the risk for DILI and its clinical expression. Genomic DNA from 154 patients (74 men, 80 women; mean age, 53 years) with a diagnosis of DILI as assessed with the Council for International Organizations of Medical Science scale and 250 sex- and age-matched healthy controls were analyzed. A multiplex polymerase chain reaction-based method was used to detect GSTM1 and GSTT1 gene deletions. Carriers of double GSTT1-M1 null genotypes had a 2.70-fold increased risk of developing DILI compared with noncarriers (odds ratio 2.70, 95% confidence interval 1.45-5.03; P = 0.003). The odds ratio for DILI patients receiving antibacterials, and NSAIDs were 3.52 (P = 0.002), and 5.61 (P = 0.001), respectively. Patients with amoxicillin-clavulanate hepatotoxicity (n = 32) had a 2.81-fold increased risk (P = 0.037). Patients classified by the combined GSTT1 and GSTM1 null genotypes did not differ with regard to the type of injury, clinical presentation, or outcome, except for the predominance of women in the combined null genotype (P < 0.001).

CONCLUSIONS

The double-null genotype for GSTT1 and GSTM1 might play a role in determining the susceptibility to develop DILI, as a general mechanism that occurs regardless of the type of drug involved, and predominantly in women.

Multiple sclerosis (MS) is a complex autoimmune disorder of the CNS with both genetic and environmental contributing factors. Clinical symptoms are broadly characterized by initial onset, and progressive debilitating neurological impairment. In this study, RNA from MS chronic active and MS acute lesions was extracted, and compared with patient matched normal white matter by fluorescent cDNA microarray hybridization analysis. This resulted in the identification of 139 genes that were differentially regulated in MS plaque tissue compared to normal tissue. Of these, 69 genes showed a common pattern of expression in the chronic active and acute plaque tissues investigated (Pvalue<0.0001, rho=0.73, by Spearman's rho analysis); while 70 transcripts were uniquely differentially expressed >> or = 1.5-fold) in either acute or chronic active tissues. These results included known markers of MS such as the myelin basic protein (MBP) and glutathione S-transferase (GST) M1, nerve growth factors, such as nerve injury-induced protein 1 (NINJ1), X-ray and excision DNA repair factors (XRCC9 and ERCC5) and X-linked genes such as the ribosomal protein, RPS4X. Primers were then designed for seven array-selected genes, including transferrin (TF), superoxide dismutase 1 (SOD1), glutathione peroxidase 1 (GPX1), GSTP1, crystallin, alpha-B (CRYAB), phosphomannomutase 1 (PMM1) and tubulin beta-5 (TBB5), and real time quantitative (Q)-PCR analysis was performed. The results of comparative Q-PCR analysis correlated significantly with those obtained by array analysis (r=0.75, Pvalue<0.01, by Pearson's bivariate correlation). Both chronic active and acute plaques shared the majority of factors identified suggesting that quantitative, rather than gross qualitative differences in gene expression pattern may define the progression from acute to chronic active plaques in MS.

This study was undertaken to examine if glutathione S-transferase (GST) M1, M3, P1, and T1 genotypes affected breast cancer risk in Finnish women. The study population consisted of 483 incident breast cancer cases and 482 healthy population controls. Genotyping analyses were performed by PCR-based methods, and odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by unconditional logistic regression adjusting for known or suspected risk factors for breast cancer. When the genes were studied separately, the only significant finding was between GSTM1 null genotype and postmenopausal breast cancer risk (OR, 1.49; 95% CI, 1.03-2.15). Conversely, when the potential combined effects of the at-risk genotypes were examined, significant associations were observed only among premenopausal women. Although only a moderate risk of breast cancer was seen for premenopausal women concurrently carrying the GSTM3*B allele containing genotypes and the GSTP1 Ile/ Ile genotype (OR, 2.07; 95% CI, 1.02-4.18), the risk rose steeply if they simultaneously lacked the GSTT1 gene (OR, 9.93, 95% CI, 1.10-90.0). A borderline significant increase in the risk of breast cancer was also seen for premenopausal women with the combination of GSTM1 null, GSTP1 Ile/Ile, and GSTT1 null genotypes (OR, 3.96; 95% CI, 0.99-15.8). Our findings support the view that GST genotypes contribute to the individual breast cancer risk, especially in certain combinations.

The genetic polymorphisms in human glutathione S-transferases (GST) M1 and T1 have been associated with race, disease risk, and outcome of some adult cancers. Also, there are racial differences in the incidence and characteristics of childhood acute lymphoblastic leukemia (ALL). Our objectives were to compare the frequency of the null genotype for GSTM1, GSTT1, or both in children with ALL to that in healthy controls, and to determine whether GST genotype was associated with treatment outcome and prognostic factors. We studied GSTM1 and GSTT1 genotypes in somatic cell DNA from black children and white children with ALL and in 416 healthy controls, using a polymerase chain reaction technique. Ninety of 163 (55.2%) white ALL patients and 14 of 34 (41.2%) black patients were GSTM1 null, frequencies not significantly different (P = .19) than healthy controls (53.5% in whites and 27.6% in blacks), although there was a trend toward more null genotypes in black ALL patients. Twenty-three of 163 (14.1%) white ALL patients and 12 of 34 (35.3%) black ALL patients were GSTT1 null, not different (P = .34) than the frequencies in healthy controls (15.0% in whites and 24.1% in blacks). However, the frequency of the "double-null" genotype, lacking both GSTM1 and GSTT1, was higher in black patients with ALL (8 of 34 or 23.5%) than in black controls (3.9%) (P = .0005), but this was not the case in white patients with ALL (10 of 163 or 6.1%) compared to white controls (8.0%) (P = .68). In stratified analyses, the GST double-null genotype was not associated with other characteristics that might differ between whites and blacks with ALL, such as age, T-lineage immunophenotype, presenting white blood cell count, DNA index, or insurance status. The null genotype for GSTM1, GSTT1, or both was not found to be a prognostic factor for disease-free survival or probability of hematologic remission; central nervous system relapse tended to be less common in those with the GSTM1 null genotype (P = .054). The double-null genotype for GSTM1 and GSTT1 is more common among blacks but not whites with childhood ALL. These data suggest that GST genotype, coupled with unidentified additional risk factors, may play a role in risk of childhood ALL in American blacks.

Human glutathione transferases (GSTs) were shown to catalyze the reductive glutathione conjugation of aminochrome (2, 3-dihydroindole-5,6-dione). The class Mu enzyme GST M2-2 displayed the highest specific activity (148 micromol/min/mg), whereas GSTs A1-1, A2-2, M1-1, M3-3, and P1-1 had markedly lower activities (<1 micromol/min/mg). The product of the conjugation, with a UV spectrum exhibiting absorption peaks at 277 and 295 nm, was 4-S-glutathionyl-5,6-dihydroxyindoline as determined by NMR spectroscopy. In contrast to reduced forms of aminochrome (leucoaminochrome and o-semiquinone), 4-S-glutathionyl-5, 6-dihydroxyindoline was stable in the presence of molecular oxygen, superoxide radicals, and hydrogen peroxide. However, the strongly oxidizing complex of Mn3+ and pyrophosphate oxidizes 4-S-glutathionyl-5,6-dihydroxyindoline to 4-S-glutathionylaminochrome, a new quinone derivative with an absorption peak at 620 nm. GST M2-2 (and to a lower degree, GST M1-1) prevents the formation of reactive oxygen species linked to one-electron reduction of aminochrome catalyzed by NADPH-cytochrome P450 reductase. The results suggest that the reductive conjugation of aminochrome catalyzed by GSTs, in particular GST M2-2, is an important cellular antioxidant activity preventing the formation of o-semiquinone and thereby the generation of reactive oxygen species.

BACKGROUND

The glutathione S-transferases (GST) mediate exposure to various cytotoxic and genotoxic agents, including those associated with increased risk of the myelodysplastic syndromes (MDS). Both GST M1 (GSTM1) and GST theta 1 (GSTT1) genes have a "null" variant allele, in which the entire gene is absent. We tested whether the homozygous null genotype of GSTM1 and GSTT1 altered the risk for MDS.

METHODS

In a hospital-based case-control study we analysed lymphocyte or bone-marrow DNA samples from 96 patients with MDS and 201 cancer-free controls of similar age, race, and sex. We have restricted our report to the 92 white MDS patients. We analysed GSTM1 and GSTT1 genotypes by PCR.

RESULTS

The frequency of the GSTT1 null genotype was higher among MDS cases (46%) than among controls (16%). Inheritance of the GSTT1 null genotype conferred a 4.3-fold of MDS (odds ratio 4.3, 95% CI 2.5-7.4, p < 0.00001). The GSTM1 null genotype was not associated with increased risk of MDS (odds ratio 0.8, 0.5-1.3).

CONCLUSIONS

Individuals with the GSTT1 null genotype may have enhanced susceptibility to MDS. The mechanism might involve decreased detoxification of environmental or endogenous carcinogens.

BACKGROUND

Genetic polymorphisms of drug-metabolizing enzymes have recently been shown to affect susceptibility to chemical carcinogenesis. However, the molecular mechanisms of individual susceptibility to gastric cancer have not been fully understood. Therefore, we studied the relationship between the genetic polymorphisms of drug-metabolizing enzymes, drinking habits, histological subtypes, and p53 gene point mutations in Japanese patients with gastric cancer.

METHODS

The genotypes of cytochromes P450 ( CYP) 1A1 and 2E1, glutathione S-transferase ( GST) M1, and N-acetyltransferase ( NAT) were investigated by polymerase chain reaction (PCR), allele-specific PCR, or restriction fragment length polymorphism (RFLP) following PCR in 146 Japanese patients with gastric cancer (67 intestinal-type and 79 diffuse-type carcinomas) and 177 autopsied controls. In addition, p53 gene point mutations of exons 5 through 9 in gastric cancer tissues were determined.

RESULTS

The frequency of either being a habitual drinker or having a CYP2E1(*) 1A/(*) 1A genotype was significantly higher in patients with intestinal-type gastric cancer than in control subjects. The difference between the frequencies of habitual drinkers with the CYP2E1(*) 1A/(*) 1A genotype and non-drinkers with the CYP2E1(*) 5B allele was much more significant in the intestinal-type cancer versus the control group. Among intestinal-type cancer patients with the CYP2E1(*) 1A/(*) 1A genotype, p53 point mutations were significantly more frequent in the group of habitual drinkers than in that of non-drinkers. On the other hand, the combination of GSTM1 null and CYP2E1(*) 1A/(*) 1A genotypes increased the risk for diffuse-type gastric cancer, but had no influence on the frequency of p53 gene mutations.

CONCLUSIONS

The present study suggests that individuals with both the CYP2E1(*) 1A/(*) 1A genotype and a history of habitual drinking have an increased risk of intestinal-type gastric cancer with a high frequency of p53 gene point mutations in the gastric mucosa.

BACKGROUND

Prenatal and infant acetaminophen exposure has been associated with an increased risk of childhood asthma phenotypes. Demonstration of biologically plausible interactions between these exposures and maternal and child antioxidant gene polymorphisms would strengthen causal inference.

OBJECTIVE

To explore potential interactions between prenatal and infant acetaminophen exposure and antioxidant genotypes on childhood asthma.

METHODS

In the Avon Longitudinal Study of Parents and Children, we typed a functional nuclear erythroid 2 p45-related factor 2 (Nrf2) polymorphism and glutathione S-transferase (GST) M1, T1, and P1 polymorphisms. Effects of prenatal and infant acetaminophen exposure on asthma phenotypes at 7 years were stratified by genotype in >4000 mothers and >5000 children.

RESULTS

Risk of asthma and wheezing associated with early gestation acetaminophen exposure was increased when maternal copies of the minor T allele of Nrf2 were present (P interactions, .02 and .04, respectively). Risk of asthma associated with late gestation exposure was higher when maternal GSTT1 genotype was present rather than absent (P interaction, .006), and risk of wheezing was increased when maternal GSTM1 was present (P interaction, .04). Although acetaminophen use in infancy was associated with an increased risk of atopy, child antioxidant genotype did not modify associations between infant acetaminophen use and asthma phenotypes. However, the increased risk of asthma and wheezing associated with late gestation acetaminophen exposure in the presence of maternal GSTM1 was further enhanced when GSTM1 was also present in the child.

CONCLUSIONS

Maternal antioxidant gene polymorphisms may modify the relation between prenatal acetaminophen exposure and childhood asthma, strengthening evidence for a causal association. In contrast, relations between infant acetaminophen use and asthma and atopy were not modified by child genotype and may be confounded by pre-existing wheeze or allergy.

We investigated the role of glutathione S-transferase (GST) enzymes (M1, T1), methylenetetrahydrofolate (MTHFR) 677 and 1298, and the NAD(P)H:quinone oxidoreductase (NQO1) polymorphisms in a population-based bladder cancer case-control study in Argentina. Buccal cell DNA was obtained from 106 cases and 109 controls. The strongest evidence was for an interaction between NQO1 genotype and smoking. For ever smoking vs. never smoking the odds ratio was 8.6 (95% confidence interval (CI) 2.7-27), in the CC genotype, and 1.3 (95% CI 0.5-3.5) in the CT and TT genotypes combined. Also, elevated bladder cancer risks associated with GSTM1 and GSTT1 null genotypes were found in smokers. Having both null polymorphisms conferred the highest risks. The MTHFR 677 CT and TT polymorphisms appeared protective against bladder cancer.