Human glutathione S-transferase P1 polymorphisms: relationship to lung tissue enzyme activity and population frequency distribution

Prevalence and persistence of chromosomal damage and susceptible genotypes of metabolic and DNA repair genes in Chinese vinyl chloride-exposed workers

Vinyl chloride (VC) was classified as a group 1 carcinogen by IARC in 1987. Although the relationship between VC exposure and liver cancer has been established, the mechanism of VC-related carcinogenesis remains largely unknown. Previous epidemiological studies have shown that VC exposure is associated with increased genotoxicity in humans. To explore chromosomal damage and its progression, and their association to genetic susceptibility, we investigated 402 workers exposed to VC, a 77 VC-exposed cohort and 141 unexposed subjects. We measured the frequencies of cytokinesis-block micronucleus (CBMN) to reflect chromosomal damage and conducted genotyping for six xenobiotic metabolisms and five DNA repair genes' polymorphism. Data indicate that 95% of the control workers had CBMN frequencies </=3 per thousand, whereas VC-exposed workers had the 3.73-fold increase compared with the controls. Among the cohort workers who were followed from 2004 to 2007, the mean CBMN frequency was higher in 2007 than in 2004 with ratio of 2.08. Multiple Poisson regression analysis showed that mean CBMN frequencies were significantly elevated for the intermediate and high exposure groups than the low. Exposed workers with CYP2E1 or XRCC1 variance showed a higher CBMN frequency than their wild-type homozygous counterparts, so did workers with GSTP1 or ALDH2 genotype. This study provides evidence that cumulative exposure dose of VC and common genetic variants in genes relevant to detoxification of carcinogens are the major factors that modulate CBMN induction in VC-exposed workers.

Modulation of cellular redox state underlies antagonism between oxaliplatin and cetuximab in human colorectal cancer cell lines

BACKGROUND AND PURPOSE

Oxaliplatin is the first platinum-based compound effective in the treatment of colorectal cancer. Oxaliplatin combined with cetuximab for metastatic colorectal cancer is under evaluation. The preliminary results seem controversial, particularly for the use of cetuximab in K-Ras mutated patients. K-Ras mutation is known to affect redox homeostasis. Here we evaluated how the efficacy of oxaliplatin alone or combined with cetuximab varied according to the Ras mutation and redox status in a panel of colorectal tumour cell lines.

EXPERIMENTAL APPROACH

Viability was evaluated by methylthiazoletetrazolium assay, reactive oxygen species production by DCFDA and lucigenin on HT29-D4, Caco-2, SW480 and SW620 cell lines.

KEY RESULTS

Combination of oxaliplatin and cetuximab was less cytotoxic than oxaliplatin alone in colorectal cells harbouring wild-type Ras and membrane expression of receptors for epidermal growth factor receptor (EGFR), such as HT29-D4 and Caco-2 cells. In contrast, cetuximab did not affect oxaliplatin efficiency in cells harbouring K-Ras(V12) mutation, irrespective of membrane EGFR expression (SW620 and SW480 cells). Transfection of HT29-D4 with K-Ras(V12) decreased oxaliplatin IC(50) and impaired cetuximab sensitivity, without affecting expression of membrane EGFR compared with HT29-D4 control. Oxaliplatin efficacy relies on endogenous production of H(2)O(2). Cetuximab inhibits H(2)O(2) production inhibiting the EGFR/Nox1 NADPH oxidase pathway. Oxaliplatin efficacy was impaired by short hairpin RNA for Nox1 and by catalase (H(2)O(2) scavenger).

CONCLUSIONS AND IMPLICATIONS

Cetuximab limited oxaliplatin efficiency by affecting the redox status of cancer cells through Nox1. Such combined therapy might be improved by controlling H(2)O(2) elimination.

Prenatal acetaminophen exposure and risk of wheeze at age 5 years in an urban low-income cohort

BACKGROUND

Acetaminophen has been associated with asthma and is in part metabolised via the glutathione pathway. Inner-city minority children have high asthma morbidity and a relatively high frequency of a minor allele variant in the glutathione S transferase Pi gene (GSTP1). We hypothesised that prenatal acetaminophen exposure would predict wheeze at age 5 years in an inner-city minority cohort and examined whether this association was modified by common polymorphisms in genes related to the glutathione pathway.

METHODS

An ongoing population-based birth cohort study of Dominican Republic and African-American children in New York prospectively assessed the use of analgesics during pregnancy and current wheeze at age 5 years in 301 children. Genotyping was conducted for GST polymorphisms. Binomial regression was used to adjust for potential confounders including postnatal acetaminophen use.

RESULTS

34% of mothers reported acetaminophen use during pregnancy and 27% of children had current wheeze at 5 years. Prenatal exposure to acetaminophen predicted current wheeze (multivariate relative risk 1.71; 95% CI 1.20 to 2.42; p=0.003), and the risk increased monotonically with increasing number of days of prenatal acetaminophen exposure (p trend <0.001). 68% of children had at least one copy of the GSTP1 minor allele (Val). The risk of wheeze was modified by GSTP1 (additive interaction p=0.009) and was observed only among children with the GSTP1 minor allele.

CONCLUSIONS

Prenatal exposure to acetaminophen predicted wheeze at age 5 years in an inner-city minority cohort. The risk was modified by a functional polymorphism in GSTP1, suggesting a mechanism involving the glutathione pathway.

Prenatal acetaminophen exposure and risk of wheeze at age 5 years in an urban low-income cohort

BACKGROUND

Acetaminophen has been associated with asthma and is in part metabolised via the glutathione pathway. Inner-city minority children have high asthma morbidity and a relatively high frequency of a minor allele variant in the glutathione S transferase Pi gene (GSTP1). We hypothesised that prenatal acetaminophen exposure would predict wheeze at age 5 years in an inner-city minority cohort and examined whether this association was modified by common polymorphisms in genes related to the glutathione pathway.

METHODS

An ongoing population-based birth cohort study of Dominican Republic and African-American children in New York prospectively assessed the use of analgesics during pregnancy and current wheeze at age 5 years in 301 children. Genotyping was conducted for GST polymorphisms. Binomial regression was used to adjust for potential confounders including postnatal acetaminophen use.

RESULTS

34% of mothers reported acetaminophen use during pregnancy and 27% of children had current wheeze at 5 years. Prenatal exposure to acetaminophen predicted current wheeze (multivariate relative risk 1.71; 95% CI 1.20 to 2.42; p=0.003), and the risk increased monotonically with increasing number of days of prenatal acetaminophen exposure (p trend <0.001). 68% of children had at least one copy of the GSTP1 minor allele (Val). The risk of wheeze was modified by GSTP1 (additive interaction p=0.009) and was observed only among children with the GSTP1 minor allele.

CONCLUSIONS

Prenatal exposure to acetaminophen predicted wheeze at age 5 years in an inner-city minority cohort. The risk was modified by a functional polymorphism in GSTP1, suggesting a mechanism involving the glutathione pathway.

Polymorphisms of glutathione S-transferase Mu 1, glutathione S-transferase theta 1 and glutathione S-transferase Pi 1 genes in Hodgkin's lymphoma susceptibility and progression

We tested in this study whether the polymorphisms of the glutathione S-transferase Mu1 (GSTM1), glutathione S-transferase Theta 1 (GSTT1) and glutathione S-transferase Pi 1 (GSTP1), involved in metabolism of chemical agents, cell proliferation and cell survival, alter the risk for Hodgkin lymphoma (HL). Genomic DNA from 110 consecutive patients with HL and 226 controls was analysed by polymerase chain reaction and restriction digestion for the polymorphism analyses. Similar frequencies of the GSTM1 and GSTT1 genotypes were seen in patients and controls. In contrast, the frequency of the GSTP1 wild genotype (59.1%versus 36.3%, P = 0.004) was higher in patients than in controls. Individuals with the wild genotype had a 2.68 (95%CI: 1.38-5.21)-fold increased risk for the disease than others. An excess of the GSTP1 wild genotype was also observed in patients with tumors of stages III + IV when compared with those with tumors of stages I + II (39.1%versus 20.0%, P = 0.03). These results suggest that the wild allele of the GSTP1 gene is linked to an increased risk and high aggressiveness of the HL in our cases but they should be confirmed by further studies with larger cohorts of patients and controls.

Glutathione S-transferase polymorphisms and survival in African-American and white colorectal cancer patients

BACKGROUND

Glutathione S-transferase (GST) enzymes are involved in electrophile detoxification. The authors investigated the association between GST genotype and survival in a racially diverse, population-based cohort of colorectal cancer (CRC) patients followed for a median of 9.6 years.

METHODS

Interviews were conducted with 315 African-American and White CRC patients in Connecticut, 1987-1991. Tumor tissue (n=197) was later retrieved from hospital of diagnosis and assayed using multiplex PCR (GSTM1 and GSTT1) and PCR and RFLP analysis (GSTP1). Cox proportional hazards models provided adjusted hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

Individuals with Ile/Val or Val/Val GSTP1 genotypes had a decreased risk of death (multivariate adjusted HR=0.72, 95% CI: 0.48, 1.09) relative to those with wild type (Ile/Ile). Among those who received chemotherapy, this benefit was more pronounced (HR=0.35, 95% CI: 0.16, 0.79); the interaction of reduced function GSTP1 genotype and chemotherapy was significant (P=0.05). GSTM1 and GSTT1 genotype were not associated with survival. GSTM1, GSTT1, and GSTP1 genotype did not vary by race and did not contribute significantly to the survival disadvantage observed in African-Americans.

CONCLUSIONS

In summary, GSTP1 genotype may play a role in CRC survival in African-Americans and Whites, particularly among those who receive chemotherapy.

The glutathione-S-transferase gene polymorphisms (Gstt1, Gstm1, and Gstp1) in patients with non-allergic nasal polyposis

There is an ongoing dilemma about the pathogenesis of nasal polyp (NP). The etiology of NP is multifactorial. Reactive oxygen species and oxidative stress are also suggested to be among the possible factors in NP development. Glutathione-S-transferase (GST) is one of the important detoxifying enzymes. It is not known whether GST plays any role in NP development. We aimed to investigate the relationship between GST subgroup (GSTT1, GSTM1, and GSTP1) polymorphisms, and NP development. Seventy-five patients with NP with or without asthma (NP with asthma: 22, NP without asthma: 53) were used as a study group. As much as 167 healthy individuals were involved as the control group. NP diagnosis was made by nasal endoscopy and paranasal sinus computed tomography (CT). NP was defined as the presence of endoscopically visible bilateral polyps originated from the middle meatus to the nasal cavity and affecting more than one paranasal sinus confirmed by CT. Blood was collected in EDTA-containing tubes and DNA was extracted from the leukocytes. The genotyping of polymorphisms of GSTT1, GSTM1, and GSTP1 were done using real time polymerase chain reaction. Chi-square (chi(2)) and Fisher's (F) exact tests were used for statistical evaluation. A 2-fold increased risk of NP could be found in individuals with the GSTT1 null genotype (OR = 2.03, 95% CI = 1.03-4.011). The distribution of GSTM1 null genotypes was not significantly different between the NP patients and controls and there was also no significance between the GSTP1 genotypes and NP. In conclusion, GST gene polymorphisms may be important in pathogenesis of NP. Additional studies which include larger study groups in different geographic localizations may be more useful to evaluate association with GST polymorphism and NP.

Glutathione S-transferase P1 Ile105Val polymorphism and colorectal cancer risk: a meta-analysis and HuGE review

Colorectal cancer is the third most common form of cancer and the fourth most frequent cause of cancer deaths worldwide. Its development is influenced by both environmental and genetic factors. The glutathione S-transferase P1 gene (GSTP1) is a particularly attractive candidate for colorectal cancer susceptibility because it codes the enzyme involved in the metabolism of environmental carcinogens such as polycyclic aromatic hydrocarbons (PAHs). However, epidemiologic findings have been inconsistent. To investigate a putative association of GSTP1 Ile105Val polymorphism with the risk of colorectal cancer, we performed a meta-analysis and HuGE review of 16 published case-control studies (involving a total of 4386 colorectal cancer patients and 7127 controls). We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. Overall, the comparison of Val versus Ile allele showed no differential susceptibility to colorectal cancer (OR=0.98, 95% CI: 0.92-1.04). A protective effect was found in recessive, with an OR of 0.86 (95% CI: 0.76-0.98). Whereas no significant association was observed in either dominant or codominant model. In stratified subgroup analysis, no effect of Val allele was seen in subjects of Caucasian and Asian descent, and in healthy and hospital controls. In conclusion, the meta-analysis suggests that the GSTP1 Ile105Val polymorphism is unlikely to increase considerably the risk of sporadic colorectal cancer, and it should be confirmed in further studies.

Genetic polymorphisms of glutathione S-transferase genes GSTP1, GSTM1, and GSTT1 and risk of esophageal and gastric cardia cancers

Glutathione S-transferase (GST) enzymes are known to metabolize tobacco-related carcinogens. Previous studies on the association of functional polymorphisms of GST genes with esophageal squamous cell carcinoma have yielded conflicting but overall null results. A few studies of esophageal adenocarcinoma were likewise conflicting, but the scarcity of data is striking. We aimed to study associations of the GSTM1 and GSTT1 null deletion polymorphisms as well as the GSTP1 Ile105Val polymorphism with risks for esophageal and gastric cardia cancers. DNA was prepared from 96 and 79 cases of esophageal adenocarcinoma and squamous cell carcinoma, respectively, 126 cardia cancer cases, and 471 population-based controls. Pyrosequencing typed the GSTP1 Ile105Val polymorphism, while multiplex PCR detected GSTM1 and GSTT1 deletions. Logistic regression modeling estimated odds ratios (ORs) with 95% confidence intervals (CIs). None of the studied polymorphisms were related to the risk of esophageal adenocarcinoma, but the variant GSTP1 Val(105) allele was associated with an increased risk of esophageal squamous cell carcinoma (OR = 1.7; 95% CI 1.0-2.9) and tended to be weakly, positively linked to cardia cancer (OR = 1.4; 95% CI 0.9-2.1). Finally, we performed a meta-analysis and found that GSTP1 polymorphism seems to be associated with the risk of esophageal squamous cell carcinoma among Caucasian population (OR = 1.4; 95% CI 1.0-2.2; p value for heterogeneity test 0.34).

Glutathione-S-transferase genotypes influence prognosis in follicular non-Hodgkin's Lymphoma

Polymorphisms in detoxification enzymes of the glutathione S-transferase (GST) family have been associated with risk and prognosis of several cancer types. We studied deletions of GSTM1 and GSTT1, and the GSTP1 Ile(105)Val polymorphism in 89 patients with follicular lymphoma (FL). Patients with a GSTM1 or GSTT1 deletion had a significantly worse event-free survival, when compared with patients with undeleted genotype (p = 0.03 and p = 0.03, respectively). Outcome was even worse in patients with a double negative genotype, in comparison with patients with only one GST deletion or normal genotype (p = 0.01). In the multivariate analysis, the GSTM1/GSTT1 genotype tended to have a prognostic significance independent from the Follicular Lymphoma International Prognostic Index (FLIPI) score. In particular, GSTM1/T1 deletions identified patients with negative prognosis in the low (<3) FLIPI score group (p = 0.01). Larger prospective studies including homogeneously treated patients will be needed to confirm these results.

MRP2 and GSTP1 polymorphisms and chemotherapy response in advanced non-small cell lung cancer

PURPOSE

The level of drug metabolism and drug transport is correlated with the sensitivity of cancer cells towards platinum-based chemotherapy. We hypothesize that genetic polymorphisms in metabolising enzymes gene GSTP1 (glutathione S-transferase P1), and MRP2 (multidrug resistance-associated protein 2) (ABCC2), which result in inter-individual differences in metabolism and drug disposition, may predict clinical response to platinum agents in advanced non-small cell lung cancer (NSCLC) patients.

METHODS

Totally 113 patients with advanced NSCLC were routinely treated with platinum-based chemotherapy, and clinical response was evaluated after four cycles. MRP2 C-24T (-24C>T), MRP2 Val417Ile (1249G>A), MRP2 Ile1324Ile (3972C>T), and GSTP1 Ile105Val (342A>G) genotype were determined by gene-chip method (a 3-D (three dimensions) polyacrylamide gel-based DNA microarray method) using DNA samples isolated from peripheral blood collected before treatment. Pearson Chi-square test and Fisher's exact test were performed to measure the differences of the chemotherapeutic efficacy among variant genotype. The odds ratios and 95% confidence intervals were computed by logistic regression.

RESULTS

The C-->T change of MRP2 C-24T and the A-->G change of GSTP1 Ile105Val polymorphism significantly increased platinum-based chemotherapy response.

CONCLUSION

The polymorphic status of MRP2 C-24T and GSTP1 Ile105Val might be the predictive markers for the treatment response of advanced NSCLC patients. The DNA microarray-based method is accurate, high throughput and inexpensive, suitable for single-nucleotide polymorphism genotyping in a large number of individuals.

Pharmacogenetics of fluoropyrimidine and cisplatin. A future application to gastric cancer treatment

Chemotherapy plays an important role in the treatment of gastric cancer both in adjuvant or advanced settings. Recent randomized trials in Japan have proved that S-1, a novel fluoropyrimidine derivative, and cisplatin are the most promising agents. However, both the efficacy and toxicity of a given regimen vary widely among patients due to the inherited variability of genes that involve drug anabolism and catabolism. A narrow therapeutic index of antitumor agents, i.e. a given regimen being too toxic and/or less effective to some segment of patients, prevents the overall improvement of treatment outcomes. Pharmacogenetics, a research field elucidating genetic polymorphism in drug metabolizing enzymes, may contribute to identifying patients who benefit from chemotherapy or who will experience life-threatening toxicity. There are several crucial enzymes identified involving anabolism and the catabolism of fluoropyrimidine and cisplatin, including dihydropyrimidine dehydrogenase, thymidylate synthase, orotate phosphoribosyl transferase, glutathione S transferase, and excision repair cross complementary group. Various polymorphisms and ethnic variabilities of these genes have been elucidated. This review highlights variations within biological functions, detection systems, and possible clinical applications of these enzymatic polymorphisms. This knowledge provides a tool to determine an optimum regimen according to the patient's drug metabolizing characteristics. This stance will contribute to establishing individualized therapies for gastric cancer, which offers superior efficacy with a minimal chance of severe toxicity.

Pharmacokinetics and pharmacogenomics in gastric cancer chemotherapy

Despite extensive efforts, treatment of gastric cancer by chemotherapy, the globally accepted standard, is yet undetermined, and uncertainty remains regarding the optimal regimen. Recent introduction of active "new generation agents" offers hope for improving patient outcomes. Current chemotherapeutic trials provided several regimens that may become a possible standard treatment, including docetaxel/cisplatin/5-FU (TCF) and cisplatin/S-1 for advanced and metastatic cancer and S-1 monotherapy in the adjuvant setting. Along with the development of novel active regimens, individual optimization of cancer chemotherapy has been attempted in order to reduce toxicity and enhance tumor response. Unlike the rare and limited contribution of pharmacokinetic studies, pharmacogenomic studies are increasing the potential to realize the therapeutics against gastric cancer. Despite the limited data, pharmacogenomics in gastric cancer have provided a number of putative biomarkers for the prediction of tumor response to chemotherapies and of toxicity.

In utero smoke exposure, glutathione S-transferase P1 haplotypes, and respiratory illness-related absence among schoolchildren

BACKGROUND

The GSTP1 Ile105Val variant and secondhand tobacco smoke exposure have been independently associated with acute respiratory illness; however, susceptibility to in utero and secondhand tobacco smoke has yet to be examined in relation to variation across the GSTP1 locus.

OBJECTIVE

The purpose of this work was to determine whether variation across the GSTP1 locus is associated with respiratory illness-related school absences and to determine whether this relationship varies by in utero and secondhand tobacco smoke exposure.

METHODS

Tobacco smoke exposure status, incident respiratory-related school absence records, and DNA samples was ascertained for 1132 Hispanic and non-Hispanic white elementary school children as part of the Children's Health Study.

RESULTS

Four GSTP1 single-nucleotide polymorphisms were selected that accounted for 93% of the variation across the locus. Individual single-nucleotide polymorphism analyses showed a protective effect for the minor alleles in single-nucleotide polymorphisms 1 (rs6591255), 3 (GSTP1 Ile105Val: rs1695), and 4 (rs749174) for respiratory illness. The haplotype, which includes a minor allele for single-nucleotide polymorphisms 1, 3, and 4 (h1011), was associated with a decreased risk of respiratory illness. The protective effect of GSTP1 variants was lost among individuals exposed to in utero and secondhand tobacco smoke.

CONCLUSIONS

A common GSTP1 haplotype, which includes the functional Ile105Val polymorphism, was associated with respiratory-related school absences. The protection afforded by this haplotype was lost in children exposed to involuntary tobacco smoke. The paradigm of loss of genetic protection among those exposed to tobacco smoke has clinical and public health implications that warrant broader consideration in research and practice.

Glutathione-S-transferase P protects against endothelial dysfunction induced by exposure to tobacco smoke

Exposure to tobacco smoke impairs endothelium-dependent arterial dilation. Reactive constituents of cigarette smoke are metabolized and detoxified by glutathione-S-transferases (GSTs). Although polymorphisms in GST genes are associated with the risk of cancer in smokers, the role of these enzymes in regulating the cardiovascular effects of smoking has not been studied. The P isoform of GST (GSTP), which catalyzes the conjugation of electrophilic molecules in cigarette smoke such as acrolein, was expressed in high abundance in the mouse lung and aorta. Exposure to tobacco smoke for 3 days (5 h/day) decreased total plasma protein. These changes were exaggerated in GSTP(-/-) mice. Aortic rings isolated from tobacco smoke-exposed GSTP(-/-) mice showed greater attenuation of ACh-evoked relaxation than those from GSTP(+/+) mice. The lung, plasma, and aorta of mice exposed to tobacco smoke or acrolein (for 5 h) accumulated more acrolein-adducted proteins than those tissues of mice exposed to air, indicating that exposure to tobacco smoke results in the systemic delivery of acrolein. Relative to GSTP(+/+) mice, modification of some proteins by acrolein was increased in the aorta of GSTP(-/-) mice. Aortic rings prepared from GSTP(-/-) mice that inhaled acrolein (1 ppm, 5 h/day for 3 days) or those exposed to acrolein in an organ bath showed diminished ACh-induced arterial relaxation more strongly than GSTP(+/+) mice. Acrolein-induced endothelial dysfunction was prevented by pretreatment of the aorta with N-acetylcysteine. These results indicate that GSTP protects against the endothelial dysfunction induced by tobacco smoke exposure and that this protection may be related to the detoxification of acrolein or other related cigarette smoke constituents.

An updating meta-analysis of the GSTM1, GSTT1, and GSTP1 polymorphisms and prostate cancer: a HuGE review

It has been postulated that individuals with GSTM1, GSTT1 deficiency and, GSTP1 (105Ile/Val transition) have increased susceptibility to carcinogens and are more likely to develop prostate cancer. In recent years, GST status has been extensively studied as a prostate cancer risk factor; however, the results are inconsistent. To re-examine this controversy, we have undertaken an updating meta-analysis of 29 studies with GSTM1 genotyping (4,564 prostate cancer cases and 5,464 controls), 22 studies with GSTT1 genotyping (3,837 cases and 4,552 controls), and 24 studies with GSTP1 genotyping (5,301 cases and 5,621 controls). The random effects odds ratio was 1.33 [95% confidence interval (95% CI): 1.15, 1.55; I(2) = 68.9%, P for heterogeneity = 0.00] for the GSTM1 null versus present genotype and 1.05 (95% CI: 0.86, 1.27; I(2) = 68.2%, P for heterogeneity = 0.00) for the GSTT1 null versus present genotype, and 1.06 (95% CI: 0.91, 1.24; I(2) = 71.5%, P for heterogeneity = 0.00) for the GSTP1-Val versus GSTP1-Ile allele. For GSTM1 polymorphism, similar results reached in Caucasians and Asians, with exception for Africans. No association between GSTT1 or GSTP1 polymorphisms and prostate cancer risk was detected in different racial. In conclusion, the major finding of our study suggested that GSTM1 polymorphism conferred an increasing risk of prostate cancer on a wide population basis, however, no relationship was found between GSTT1 and GSTP1 status and the risk of prostate cancer.

Polymorphism in glutathione-S-transferases: a risk factor in alcoholic liver cirrhosis

In a case-control study, association of polymorphism in glutathione-S-transferases (GSTM1, GSTT1, GSTP1), involved in detoxification of reactive oxygen species (ROS), was studied with alcoholic liver cirrhosis. The study included 175 alcoholic cirrhotic patients (ACPs), 140 non-alcoholic cirrhotic patients (NACPs), visiting Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGI), Lucknow, India, 255 non-alcoholic controls and 140 alcoholic controls. The data showed an increase in risk to alcoholic cirrhosis in ACPs with GSTM1 (null) genotype when compared with non-alcoholic controls (OR: 1.7; 95% CI: 1.15-2.56) or alcoholic controls (OR: 1.7; 95% CI: 1.07-2.73). Significant increase in risk was also observed in ACPs with variant genotype of GSTP1 when compared with non-alcoholic controls (OR: 1.65; 95% CI: 1.12-2.43). A much higher risk to alcoholic liver cirrhosis was observed in patients carrying combination of null genotypes of GSTM1 and GSTT1 (OR: 2.8; 95% CI: 1.3-6.06) or variant genotype of GSTP1 and null genotype of GSTM1 (OR: 2.8; 95% CI: 1.58-4.90) or GSTT1 (OR: 2.16; 95% CI: 1.08-4.28). Likewise, greater risk for alcoholic cirrhosis was observed in patients carrying combination of GSTM1, GSTT1 (null) and variant genotype of GSTP1 (OR: 5.8; 95% CI: 2.17-15.80). Our data further showed that interaction of GSTs with variant genotype of manganese superoxide dismutase (MnSOD), which detoxifies free radicals, or cytochrome P450 2E1, which generates free radicals, resulted in several fold increase in risk to alcoholic liver cirrhosis in ACPs when compared with non-alcoholic controls thus demonstrating the role of gene-gene interactions in modulating the risk to alcoholic liver cirrhosis.

Glutathione S-transferase polymorphisms and risk of second primary malignancy after index squamous cell carcinoma of the head and neck

Glutathione S-transferases (GST) detoxify carcinogens in tobacco smoke, which plays a major role in development of not only squamous cell carcinoma of the head and neck (SCCHN) but also second primary malignancy (SPM) after index SCCHN. We hypothesized that GSTM1 null, GSTT1 null, GSTP1 Ile(105)Val, and GSTP1 Ala(114)Val polymorphisms would individually and, more likely, collectively show an association with risk of SPM after index SCCHN. One thousand three hundred seventy-six incident SCCHN patients were prospectively recruited between May 1996 and December 2006, genotyped, and followed for SPM development. One hundred ten patients (8%) developed SPM: 43 (39%) second SCCHN, 38 (35%) other tobacco-associated sites, and 29 (26%) other non-tobacco-associated sites. Patients with GSTP1 Ile(105)Val polymorphism had a statistically significant association with risk of SPM development (adjusted hazard ratio, 1.7; 95% confidence interval, 1.1-2.5). However, no statistically significant associations were observed with GSTM1, GSTT1, or GSTP1 Ala(114)Val polymorphisms. After combining risk genotypes for all four polymorphisms, rates of SPM development with 0 to 1, 2, 3, and 4 risk genotypes were 6.4%, 8.4%, 10.9%, and 15.1%, respectively, and a stepwise increase in SPM risk was observed with increasing number of risk genotypes (P = 0.004 for trend). Patients with 3 to 4 risk genotypes had a 1.7-fold increased risk for SPM compared with patients with 0 to 2 risk genotypes (hazard ratio, 1.70; 95% confidence interval, 1.2-2.5). This large prospective cohort study supports a modestly increased risk of SPM after index SCCHN with GSTP1 Ile(105)Val polymorphism and an even greater risk of SPM with multiple combined GST risk genotypes.

Association of cyclophosphamide drug-metabolizing enzyme polymorphisms and chemotherapy-related ovarian failure in breast cancer survivors

OBJECTIVE

To determine if genetic variation in chemotherapy metabolism are associated with risk of ovarian failure in breast cancer patients after adjuvant chemotherapy.

DESIGN

Prospective cohort study.

SETTING

Comprehensive cancer center.

PATIENT(S)

Early-stage breast cancer patients who were premenopausal at cancer diagnosis and treatment.

INTERVENTION(S)

None.

MAIN OUTCOMES MEASURE(S)

Chemotherapy-related ovarian failure (CROF).

RESULT(S)

A total of 127 breast cancer subjects who were premenopausal at cancer diagnosis and underwent cyclophosphamide-based chemotherapy were genotyped for nine single-nucleotide polymorphisms (SNPs) in enzymes involved in cyclophosphamide activation (CYP3A4, CYP2B6, CYP3A5) and detoxification (GSTA1, GSTM1, GSTP1, GSTT1). Median age at chemotherapy was 43.2 years. Median follow-up after chemotherapy was 5.2 years. For the entire cohort, there was no significant association between CROF and SNPs. However, the association between CROF and SNPs was modified by age at chemotherapy. In subjects younger than 45 years old at chemotherapy, CYP3A4 *1B variants had significantly longer time to CROF than CYP3A4 *1A homozygotes in an adjusted multivariable Cox model. Age and tamoxifen use were also independently associated with CROF.

CONCLUSION(S)

A common SNP in a cyclophosphamide drug-metabolizing enzyme appears to be related to ovarian failure after cyclophosphamide-based chemotherapy in young women with breast cancer. Larger prospective studies to validate these results should be directed toward women younger than 45 years of age at chemotherapy.

Pharmacogenetic study in Hodgkin lymphomas reveals the impact of UGT1A1 polymorphisms on patient prognosis

Hodgkin lymphoma is a highly curable malignancy, but treatment outcome might be influenced by inherited gene polymorphisms determining anticancer agent metabolism. We prospectively collected peripheral blood lymphocytes from 313 patients with Hodgkin lymphomas to analyze GSTP1, GSTM1, GSTT1, UGT1A1, and CYP3A4 enzyme gene polymorphisms. All patients were treated with chemotherapy, associated with radiotherapy when they had localized disease. There was no difference for GSTP1, GSTM1, and GSTT1 as well as for UGT1A1 and CYP3A4 polymorphism distributions between Hodgkin lymphoma patients and healthy controls. Patients carrying 1 or 2 UGT1A1*28 allele had a significantly (P < .05) better freedom from progression and time to treatment failure than those homozygous for the UGT1A1 TA6/TA6 allele. Multivariate prognostic analyses showed that the UGT1A1 polymorphism was as an independent prognostic parameter for all the studied endpoints, the wild-type homozygous UGT1A1 TA6/TA6 genotype being associated with a significantly worse prognosis than genotypes with at least one UGT1A1*28 allele (overall survival; relative risk [RR] = 2.54, 95% confidence interval [CI], 1.05-6.14; P = .04; freedom from progression, RR = 2.70, 95% CI, 1.37-5.31; P = .004; time to treatment failure, RR = 2.37, 95% CI, 1.28-4.40, P = .006). UGT1A1 polymorphism on TA repeats, which are thought to determine several anticancer drugs metabolism, influence Hodgkin lymphoma patient outcome.

PAH-DNA adducts, cigarette smoking, GST polymorphisms, and breast cancer risk

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) may increase breast cancer risk, and the association may be modified by inherited differences in deactivation of PAH intermediates by glutathione S-transferases (GSTs). Few breast cancer studies have investigated the joint effects of multiple GSTs and a PAH biomarker.

OBJECTIVE

We estimated the breast cancer risk associated with multiple polymorphisms in the GST gene (GSTA1, GSTM1, GSTP1, and GSTT1) and the interaction with PAH-DNA adducts and cigarette smoking.

METHODS

We conducted unconditional logistic regression using data from a population-based sample of women (cases/controls, respectively): GST polymorphisms were genotyped using polymerase chain reaction and matrix-assisted laser desorption/ionization time-of-flight assays (n = 926 of 916), PAH-DNA adduct blood levels were measured by competitive enzyme-linked immunosorbent assay (n = 873 of 941), and smoking status was assessed by in-person questionnaires (n = 943 of 973).

RESULTS

Odds ratios for joint effects on breast cancer risk among women with at least three variant alleles were 1.56 [95% confidence interval (CI), 1.13-2.16] for detectable PAH-DNA adducts and 0.93 (95% CI, 0.56-1.56) for no detectable adducts; corresponding odds ratios for three or more variants were 1.18 (95% CI, 0.82-1.69) for ever smokers and 1.44 (95% CI, 0.97-2.14) for never smokers. Neither interaction was statistically significant (p = 0.43 and 0.62, respectively).

CONCLUSION

We found little statistical evidence that PAHs interacted with GSTT1, GSTM1, GSTP1, and GSTA1 polymorphisms to further increase breast cancer risk.

Haplotype-tagging single nucleotide polymorphisms in the GSTP1 gene promoter and susceptibility to lung cancer

BACKGROUND

Glutathione S-transferase (GST) P1 is a major phase II xenobiotic-metabolizing enzyme in the human lung. Our laboratory had previously identified nine single nucleotide polymorphisms (SNPs) in the GSTP1 gene promoter, which were then grouped into three main haplotypes (Hap1, Hap2, and Hap3) based on statistical inference. Hap3 was found to display a high expression phenotype. The main objective of the current study was to test the association between GSTP1 promoter haplotypes with the risk of lung cancer after determining the promoter haplotypes experimentally through cloning and sequencing.

METHODS

We conducted a case-control analysis of 150 subjects with lung cancer and 329 controls with no personal history of the disease. The three statistically inferred GSTP1 promoter haplotypes were confirmed experimentally through cloning and sequencing. Haplotype-tagging SNPs were selected and GSTP1 haplotypes were tested for genetic association to lung cancer using unconditional logistic regression after adjusting for confounders. Statistical interaction between GSTP1 promoter haplotypes with either cigarette smoking or dietary fruit and vegetable intake were tested using the likelihood ratio test.

RESULTS

We did not find protective effects of Hap3 against lung cancer, despite an adequately powered design for this main effect. Homozygous variants of tagSNPs -1738 T>A and -354 G>T, which tag Hap2, showed an increased (but statistically non-significant) risk of lung cancer among all subjects as well as among individuals with low fruit and vegetable intake, compared to homozygous wildtypes for these SNPs. We did not find significant interactions between Hap2 and dietary intake of fruits and vegetables.

CONCLUSIONS

Our results do not support significant main and modifying effects for GSTP1 promoter haplotypes on susceptibility to lung cancer in this population, but reinforce the protective effects of dietary intake of fruits and vegetables.

Polymorphisms of glutathione-S-transferase M1, T1, P1 and the risk of prostate cancer: a case-control study

Background

It has been suggested that polymorphisms in glutathione-S-transferases (GST) could predispose to prostate cancer through a heritable deficiency in detoxification pathways for environmental carcinogens. Yet, studies linking GST polymorphism and prostate cancer have so far failed to unambiguously establish this relation in patients. A retrospective study on healthy, unrelated subjects was conducted in order to estimate the population GST genotype frequencies in the Slovak population of men and compare our results with already published data (GSEC project-Genetic Susceptibility to Environmental Carcinogens). A further aim of the study was to evaluate polymorphisms in GST also in patients with prostate cancer in order to compare the evaluated proportions with those found in the control subjects.

Methods

We determined the GST genotypes in 228 healthy, unrelated subjects who attended regular prostate cancer screening between May 2005 and June 2007 and in 129 histologically verified prostate cancer patients. Analysis for the GST gene polymorphisms was performed by PCR and PCR-RFLP.

Results

We found that the GST frequencies are not significantly different from those estimated in a European multicentre study or from the results published by another group in Slovakia. Our results suggest that Val/Val genotype of GSTP1 gene could modulate the risk of prostate cancer, even if this association did not reach statistical significance. We did not observe significantly different crude rates of the GSTM1 and GSTT1 null genotypes in the men diagnosed with prostate cancer and those in the control group.

Conclusion

Understanding the contribution of GST gene polymorphisms and their interactions with other relevant factors may improve screening diagnostic assays for prostate cancer. We therefore discuss issues of study feasibility, study design, and statistical power, which should be taken into account in planning further trials.

Associations between multiple environmental exposures and Glutathione S-Transferase P1 on persistent wheezing in a birth cohort

OBJECTIVE

To determine the impact of environmental exposures (diesel exhaust particle [DEP], environmental tobacco smoke [ETS], and mold) that may contribute to oxidative stress on persistent wheezing in the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS) birth cohort and to determine how the impact of these exposures is modified by the GST-P1 Ile105Val polymorphism.

STUDY DESIGN

A land-use regression model was used to derive an estimate of each child's DEP exposure. ETS exposure was determined by questionnaire data. Each child's home was evaluated for visible mold by a trained professional. Children in the CCAAPS cohort were genotyped for the GST-P1 polymorphism (n = 570). Persistent wheezing was defined as wheezing at both 12 and 24 months.

RESULTS

High DEP exposure conferred increased risk for wheezing phenotypes but only among the Val(105) allele carriers. Infants with multiple exposures were significantly more likely to persistently wheeze despite their genotype.

CONCLUSION

There is evidence for an environmental effect of DEP among carriers of the GST-P1 Val(105) allele in the development of persistent wheezing in children. The protective effect of the GST-P1 Ile(105) genotype may be overwhelmed by multiple environmental exposures that converge on oxidative stress pathways.

Glutathione-S-transferase-P1 I105V polymorphism and response to antenatal betamethasone in the prevention of respiratory distress syndrome

PURPOSE

The aim of this pilot study was to assess the association between polymorphisms in genes that encode for proteins involved in the pharmacokinetics/pharmacodynamics of glucocorticoids and the occurrence of respiratory distress syndrome (RDS) in preterm infants born to mothers treated with a complete course of betamethasone.

METHODS

Sixty-two preterm infants were enrolled. The C1236T, G2677T, and C3435T polymorphisms in the ABCB1 gene, BclI, N363S and ER22/23EK in the NR3C1 gene, I105V in the GST-P1 gene and GST-M1 and GST-T1 deletions were analyzed, and their association with the occurrence of RDS was assessed.

RESULTS

In univariate analysis, the heterozygous and homozygous presence of the I105V variant in the GST-P1 gene seemed to confer protection against the occurrence of RDS (P = 0.032), while no association for all other polymorphisms was observed. In multivariate analysis, selection from the reference model of independent variables based on AIC (Akaike information criteria) maintained three variables in the model: gestation, C3435T, and GST-P1 genotype.

CONCLUSIONS

Polymorphisms of the GST-P1 gene may influence the effect of antenatal steroids on the newborn lung.

Association study between the genetic polymorphisms of glutathione-related enzymes and schizophrenia in a Japanese population

Several lines of evidence suggest that oxidative stress plays a role in the pathogenesis of schizophrenia, and that glutathione (GSH) plays a crucial role in antioxidant defense mechanisms. In this study, we performed association studies between GSH-related genes (GSTM1, GSTP1, GSTO1, GSTT1, GSTT2, GPX1, and GCLM) and schizophrenia in a Japanese population. The overall distributions of the genotypes and alleles of each gene were not different between schizophrenic patients and controls. Subjects with residual-type schizophrenia showed different distributions in the analysis of GSTM1 genotype and in the combination analysis of GSTs, GPX1, and GCLM genotypes although the small sample size should be considered as a limitation of this study. In addition, our findings revealed that there were large ethnic differences in the genotype distributions of those GSH-related genes. The present study suggests that GSH-related genes may not play a major role in the pathogenesis of schizophrenia in a Japanese population. However, a dysregulation of GSH metabolism may be one of the vulnerability factors contributing to the development of a certain type of schizophrenia, and it is likely that the ethnic background should be considered in further study for those GSH-related genes.

Genetic Polymorphism in Glutathione Transferases (GST): Population distribution of GSTM1, T1, and P1 conjugating activity

Glutathione transferases (GST) catalyze the conjugation of glutathione (GSH) with electrophiles, many of which may otherwise interact with protein or DNA. In select cases such as halogenated solvents, GST-mediated conjugation may lead to a more toxic or mutagenic metabolite. Polymorphisms that exert substantial effects on GST function were noted in human populations for several isozymes. This analysis focuses on three well-characterized isozymes, GSTM1, T1, and P1, in which polymorphisms were extensively studied with respect to DNA adducts and cancer in molecular epidemiologic studies. The current review and analysis focused upon how polymorphisms in these GST contributed to population variability in GST function. The first step in developing this review was to characterize the influence of genotype on phenotype (enzyme function) and the frequency of the polymorphisms across major population groups for all three GST. This information was then incorporated into Monte Carlo simulations to develop population distributions of enzyme function. These simulations were run separately for GSTM1, T1, and P1, and also for the combination of these isozymes, to assess the possibility of overlapping substrate specificity. Monte Carlo simulations indicated large interindividual variability for GSTM1 and T1 due to the presence of the null (zero activity) genotype, which is common in all populations studied. Even for GSTM1 or T1 non-null individuals, there was considerable interindividual variability with a bimodal distribution of enzyme activity evident. GSTP1 polymorphisms are associated with somewhat less variability due to the absence of null genotypes. However, in all cases simulated, the estimated variability is sufficiently large to warrant consideration of GST function distributions in assessments involving GST-mediated activation or detoxification of xenobiotics. Ideally, such assessments would involve physiologically based toxicokinetic (PBTK) modeling to assess population variability in internal dose.

The influence of genetic polymorphisms on population variability in six xenobiotic-metabolizing enzymes

This review provides variability statistics for polymorphic enzymes that are involved in the metabolism of xenobiotics. Six enzymes were evaluated: cytochrome P-450 (CYP) 2D6, CYP2E1, aldehyde dehydrogenase-2 (ALDH2), paraoxonase (PON1), glutathione transferases (GSTM1, GSTT1, and GSTP1), and N-acetyltransferases (NAT1 and NAT2). The polymorphisms were characterized with respect to (1) number and type of variants, (2) effects of polymorphisms on enzyme function, and (3) frequency of genotypes within specified human populations. This information was incorporated into Monte Carlo simulations to predict the population distribution and describe interindividual variability in enzyme activity. The results were assessed in terms of (1) role of these enzymes in toxicant activation and clearance, (2) molecular epidemiology evidence of health risk, and (3) comparing enzyme variability to that commonly assumed for pharmacokinetics. Overall, the Monte Carlo simulations indicated a large degree of interindividual variability in enzyme function, in some cases characterized by multimodal distributions. This study illustrates that polymorphic metabolizing systems are potentially important sources of pharmacokinetic variability, but there are a number of other factors including blood flow to liver and compensating pathways for clearance that affect how a specific polymorphism will alter internal dose and toxicity. This is best evaluated with the aid of physiologically based pharmacokinetic (PBPK) modeling. The population distribution of enzyme activity presented in this series of articles serves as inputs to such PBPK modeling analyses.

Glutathione-S-transferase pi (GSTP1) codon 105 polymorphism is not associated with oxaliplatin efficacy or toxicity in advanced colorectal cancer patients

PURPOSE

Oxaliplatin is detoxified by conjugation to glutathione via the enzyme Glutathione-S-transferase pi (GSTP1). The aim of this study is to investigate the association of GSTP1 Ile105Val genetic polymorphism with oxaliplatin efficacy and toxicity in advanced colorectal cancer (ACC) patients.

EXPERIMENTAL DESIGN

A total of 91 ACC patients received capecitabine and oxaliplatin (CAPOX) as a part of a multicentre phase-III study of the Dutch Colorectal Cancer Group. Tumour response was evaluated according to RECIST, toxicity was graded using CTC, and GSTP1 Ile105Val was determined by pyrosequencing.

RESULTS

Overall survival after CAPOX was similar for patients with the Ile/Ile (11.5 mo), Ile/Val (11.6 mo) and Val/Val (12.6 mo) genotypes (p=0.602). Likewise, there were no statistically significant differences in progression-free survival (p=0.252). Overall grades 3-4 toxicity was not related to genotype (p=0.313). There were no differences in any grade or grades 3-4 neurotoxicity amongst the patients who received > or =500 mg/m(2) of oxaliplatin (p-values of 0.376 and 0.772, respectively).

CONCLUSIONS

The results of this study indicate that the GSTP1 genotype is not predictive for progression-free survival or overall survival in ACC patients treated with CAPOX. Moreover, overall neurotoxicity and neurotoxicity in patients receiving 500 mg/m(2) of oxaliplatin was not associated with GSTP1 genotype.

Ozone exposure, antioxidant genes, and lung function in an elderly cohort: VA normative aging study

BACKGROUND

Ozone (O3) exposure is known to cause oxidative stress. This study investigated the acute effects of O(3) on lung function in the elderly, a suspected risk group. It then investigated whether genetic polymorphisms of antioxidant genes (heme oxygenase-1 (HMOX1) and glutathione S-transferase pi (GSTP1)) modified these associations.

METHODS

1100 elderly men from the Normative Aging Study were examined whose lung function (forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1)) was measured every 3 years from 1995 to 2005. The study genotyped the GSTP1 Ile105Val and Ala114Val polymorphisms and the (GT)n repeat polymorphism in the HMOX1 promoter, classifying repeats as short (n<25) or long (n> or =25). Ambient O(3) was measured continuously at locations in the Greater Boston area. Mixed linear models were used, adjusting for known confounders.

RESULTS

A 15 ppb increase in O(3) during the previous 48 h was associated with a 1.25% decrease in FEV(1) (95% CI: -1.96% to -0.54%). This estimated effect was worsened with either the presence of a long (GT)n repeat in HMOX1 (-1.38%, 95% CI: -2.11% to -0.65%) or the presence of an allele coding for Val105 in GSTP1 (-1.69%, 95% CI: -2.63% to -0.75%). A stronger estimated effect of O(3) on FEV(1) was found in subjects carrying both the GSTP1 105Val variant and the HMOX1 long (GT)n repeat (-1.94%, 95% CI: -2.89% to -0.98%). Similar associations were also found between FVC and O(3) exposure.

CONCLUSIONS

Our results suggest that O(3) has an acute effect on lung function in the elderly, and the effects may be modified by the presence of specific polymorphisms in antioxidant genes.

Relevance of glutathione S-transferase M1 and cytochrome P450 1A1 genetic polymorphisms to the development of head and neck cancers

BACKGROUND

Cytochrome P450 (CYP) and glutathione S-transferase (GST) gene variants have been intensively investigated for their implication in the development of different neoplasms.

METHODS

In the present study, we analyzed genetic polymorphisms of CYP1A1, GSTM1, GSTP1, and GSTT1 in 127 head and neck cancer patients and 151 hospital controls.

RESULTS

No significant increase in risk in patients with the GSTM1 null genotype (OR=1.52, 95% CI: 0.93-2.49) or CYP1A1 462Val alleles (OR=1.60, 95% CI: 0.73-3.52) or GSTP1 105Val alleles (OR=0.97, 95% CI: 0.59-1.58) was observed. The GSTT1 null genotype was found in 30.5% of the controls and 21.3% of the head and neck cancer patients (p=0.15). The estimated head and neck cancer risk for the combination of either CYP1A1 Ile462Val or CYP1A1 Val462Val genotype with either GSTP1 Ile105Val or Val105Val genotype (OR=2.89, 95% CI: 0.71-11.71) and for the combination of either CYP1A1 Ile462Val or CYP1A1 Val462Val genotype with GSTT1 null genotype (OR=2.62, 95% CI: 0.64-10.85) suggested the absence of the modifying effect of combined variant alleles on head and neck cancer susceptibility. The joint effect of either CYP1A1 Ile462Val or CYP1A1 Val462Val genotype with GSTM1 null genotype significantly increased the risk of head and neck cancer (OR=7.15, 95% CI: 1.49-34.32).

CONCLUSIONS

Our findings corroborate metabolic genes interactions, especially for CYP1A1 462Val alleles and GSTM1 homozygous deletion, in the development of head and neck cancer in the investigated population groups in Poland.

Association between GST genetic polymorphism and dose-related production of urinary benzene metabolite markers, trans, trans-muconic acid and S-phenylmercapturic acid

The urinary benzene metabolites, trans, trans-muconic acid (ttMA) and S-phenylmercapturic acid (SPMA), are widely used as benzene exposure biomarkers. The influence of the glutathione S-transferase (GST) genetic polymorphism on the excretion levels of urinary ttMA and/or SPMA has been investigated. The association between dose-related production of urinary benzene metabolites and benzene exposure level was also reported. However, the association between the dose-related productions of urinary benzene metabolites and GST genetic polymorphism was not described in the literature. The purpose of this study was to investigate the association between the GST genetic polymorphism and dose-related production of the two widely used biomarkers, urinary ttMA and SPMA. Seventy male workers in a chemical factory were measured for their benzene exposure levels and provided blood and urine specimens at the end of work-shift. The atmospheric benzene exposure levels of these workers were determined by passive samplers with gas chromatograph mass spectrometer. The urinary ttMA and SPMA levels were quantitated by an online dual-loop cleanup device with an electrospray ionization tandem mass spectrometer. The analyses of GST genotypes, including M(1), T(1), and P(1), were done using PCR. Mean (+/- SD) of benzene exposure levels in participants was 7.2 +/- 15 ppm. The ttMA and SPMA levels in the high benzene exposure group (> or =1 ppm) were higher than those in the low benzene exposure group (<1 ppm; P < 0.001). Among the GST genotypes investigated in this study, the results showed that only the GSTT1 genotype was related to the level and dose-related production of SPMA. Using SPMA for evaluating benzene exposure, the results suggest that the GSTT1 genetic polymorphism, especially in a comparison study between two populations with different GSTT1 genotype frequencies, should be considered. Additionally, the biological exposure index value of SPMA should be set based on the levels of subjects with GSTT1-deficient genotypes for protection of all subjects.

Drug related genetic polymorphisms affecting adverse reactions to methotrexate, vinblastine, doxorubicin and cisplatin in patients with urothelial cancer

PURPOSE

There is considerable interindividual diversity in the development of adverse reactions during chemotherapy for cancers. This diversity is suggested to be attributable to differences in the disposition of chemotherapeutic agents, which is modified by genetic polymorphisms. In this study we evaluated the possible association of polymorphisms of genes involved in the metabolism, detoxification and transport of the agents with adverse reactions to methotrexate, vinblastine, doxorubicin and cisplatin therapy.

MATERIALS AND METHODS

A total of 40 patients with urothelial cancer who received methotrexate, vinblastine, doxorubicin and cisplatin or high dose methotrexate, vinblastine, doxorubicin and cisplatin chemotherapy between 1996 and 2005 at Akita University Medical Center were included in this study. Four genetic polymorphisms (ABCB1, GSTP1, CYP3A5 and MTHFR) and clinical parameters were included in the analysis to determine whether there was any association with the grade of adverse reactions at the first cycle and the worst grade of each adverse reaction throughout the chemotherapy period.

RESULTS

On multivariate analysis the CYP3A5 A6986G genotype *3/*3 (OR 8.205, 95% CI 1.616-41.667, p = 0.011) and smaller number of treatment cycles (OR 0.156, 95% CI 0.037-0.659, p = 0.011) were independent factors for leukocytopenia (grade 3 or greater) throughout the period of chemotherapy. The mean white blood cell count nadir in patients with genotype *3/*3 was significantly lower than that in those with the *1 allele (1,542 +/- 903 vs 2,431 +/- 973/mm(3), p = 0.009).

CONCLUSIONS

The A6986G polymorphism of CYP3A5, which is involved in the metabolism of vinblastine and doxorubicin, might be a genetic predictor of the severity of leukocytopenia induced by chemotherapy with methotrexate, vinblastine, doxorubicin and cisplatin.

Genetic polymorphisms inGSTM1,GSTT1,GSTP1,GSTM3and the susceptibility to gallbladder cancer in North India

The glutathione S-transferase (GSTs) are polymorphic supergene family of detoxification enzymes that are involved in the metabolism of numerous potential carcinogens. Several allelic variants of polymorphic GSTs show impaired enzyme activity and are suspected to increase the susceptibility to various cancers. To find out the association of GST variants with risk of gallbladder cancer, the distribution of polymorphisms in the GST family of genes (GSTT1, GSTM1, GSTP1, and GSTM3) were studied in 106 cancer patients and 201 healthy controls. Genotypes were analysed by polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (RFLP). The frequencies of GSTM1 null and GSTM3*BB genotypes did not differ between patients and controls. The overall frequency of GSTT1 null was lower in cases as compared with controls (p=0.003, Odds ratio (OR) = 0.2, 95% confidence interval (CI), 0.1-0.6). After sex stratification, the GSTT1 null frequency was reduced only in female patients (p=0.008, OR = 0.2, 95% CI = 0.1-0.6). However, the GSTP1, ile/val genotype and the val allele were significantly higher in cases than controls (p=0.013, OR = 1.9, 95% CI = 1.1-3.1; p=0.027, OR = 1.5, 95% CI = 1.0-2.1), respectively. To study gene-gene interactions, a combined risk of gallbladder cancer due to ile/val or val/val were calculated in combination with null alleles of GSTM1 and GSTT1 or the *B allele of GSTM3, but there was no enhancement of risk. Gallstones were present in 57.5% of patients with gallbladder cancer, but there were no significant differences between allelic/genotype frequencies of the studied GST genes polymorphisms between patients with or without gallstones. To best of our knowledge, this is the first paper showing ile/val genotypes and val allele of GSTP1 to be associated with higher risk of gallbladder cancer.

Association study between polymorphisms in glutathione-related genes and methamphetamine use disorder in a Japanese population

Accumulating evidence suggests that oxidative stress plays a role in the mechanisms of action of methamphetamine (METH) in the brain. In the present study, we investigated the association between the genetic polymorphisms among glutathione (GSH)-related enzymes; glutathione S-transferases (GSTs) such as GSTT1 (Non-deletion/Null), GSTT2 (Met139Ile), GSTA1 (-69C/T), and GSTO1 (Ala140Asp); glutathione peroxidase 1 (GPX1) (Pro198Leu); and glutamate-cysteine ligase modifier (GCLM) subunit and METH use disorder in a Japanese population. Two hundred eighteen METH abusers and 233 healthy controls were enrolled in the study. There was a significant difference in GSTT1 genotype frequency between patients with METH psychosis and controls (P = 0.039, odds ratio: 1.52, 95% CI 1.03-2.24). Furthermore, the frequency (66.0%) of the GSTT1 null genotype among prolonged-type METH psychotic patients with spontaneous relapse was significantly higher (P = 0.025, odds ratio: 2.43, 95% CI 1.13-5.23) than that (44.4%) of transient-type METH psychotic patients without spontaneous relapse. However, there were no associations between the polymorphisms of other genes and METH abuse. The present study suggests that the polymorphism of the GSTT1 gene might be a genetic risk factor of the development of METH psychosis in a Japanese population.

Methylenetetrahydrofolate reductase C677T and glutathione S-transferase P1 A313G are associated with a reduced risk of preeclampsia in Maya-Mestizo women

Preeclampsia, a common complication of pregnancy, is characterized by elevated blood pressure and proteinuria developing after 20 weeks' gestational age. Susceptibility to this syndrome is believed to have a genetic component. The aim of this study was to investigate whether or not the 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T and glutathione S-transferase P1 (GSTP1) A313G polymorphisms are associated with preeclampsia in Maya-Mestizo women. A case-control study was performed, in which 125 preeclamptic patients and 274 healthy controls were genotyped for the MTHFR C677T and GSTP1 A313G polymorphisms by real-time PCR allelic discrimination. Allele and genotype frequencies were compared using the chi2 tests. The MTHFR 677T allele and the 677TT genotype were significantly more frequent in the controls, suggesting an association with a decreased risk of preeclampsia (p = 0.017 and p = 0.007, respectively). Similarly, GSTP1 313GG/GC genotypes and the G allele were more frequent in controls, showing a significant association with reduced risk of preeclampsia (p = 0.008 and p = 0.013, respectively). Our results suggest, for the first time, that the MTHFR 677T and GSTP1 313G polymorphisms confer a significantly decreased risk of developing preeclampsia in the Mexican Maya-Mestizo population.