Glutathione S-transferase M1 and T1 genetic polymorphisms, alcohol consumption and breast cancer risk

Association of glutathione S-transferase 1 (GSTP1) polymorphisms with Breast Cancer susceptibility

Hereditary and environmental variables have a role in the development of breast cancer. This study aimed to examine the links between genetic Variations in the GSTP1 gene and Predisposition to breast cancer in an Iraqi population. The research included 40 Iraqi female breast cancer patients and 20 healthy volunteers. GSTP1-1695 A/G gene polymorphisms were investigated using polymerase chain reaction in Real-time (RT-PCR). The results showed the GSTP1 frequency of the wild GG genotypes was showed significantly (P<0.01) higher in healthy women in comparison with Breast cancer women (GG, 80% vs. 32.5%, respectively; furthermore, heterozygous AG genotypes were significantly higher in Breast cancer women in comparison with healthy women 42.5% vs. 20%, respectively at (P<0.01). While the mutant AA genotype (25%) in patient women appeared significantly (P<0.01) higher compared to healthy women (0.0%). Finally, we discovered a connection between GSTP1 polymorphisms and a higher chance of developing breast cancer in an Iraqi female population sample. Keywords: glutathione S-transferase1, breast cancer, polymorphism.

Evaluation of molecular markers GSTM1 and GSTT1 and clinical factors in breast cancer: case-control study and literature review

The study was conducted to evaluate the frequency of polymorphisms in GSTM1 and GSTT1 genes in patients with breast cancer compared with individuals without history of cancer, and the association of these polymorphisms with clinical/epidemiological parameters.There were evaluated 752 women (219 patients and 533 controls). Molecular analysis was performed by the Polymerase Chain Reaction (PCR). Statistical analysis was used multiple logistic regression and descriptive statistics.Age ≥50 years (OR =3.22, 95% CI =2.30 - 4.51, p <0.001) and alcohol consumption (OR =1.60, 95% CI =1.13 - 2.27, p = 0.008) were associated to the development of breast cancer, while smoking and null genotypes GSTM1 and GSTT1 presented no association. GSTM1 and GSTT1 polymorphisms presented no relationship with the clinical and histopathological parameters or molecular subtypes of breast cancer. Ninety-two percent of tumors were invasive ductal, 66% were grade II, 65% were larger than 2 cm, the stages II (35.3%) and III (31.2%) were the most prevalent, and 47.7% were molecular subtype luminal B.Individuals aged ≥50 years and alcohol consumers have more chance to developing breast cancer. GSTM1 and GSTT1 polymorphisms are not associated to the risk of breast cancer.

Impact of xenobiotic-metabolizing gene polymorphisms on breast cancer risk in South Indian women

BACKGROUND

Functional variants of the xenobiotic-metabolizing genes (XMG) might modulate breast cancer (BC) risk by altering the rate of metabolism and clearance of myriad types of potent carcinogens from the breast tissue. Despite mounting evidence on the role of XMG variants on BC risk, the current knowledge regarding their influence on BC development is still fragmentary.

METHODS

The present study examined the candidate genetic variants in CYP1A1, NQO1, GST-T1, GST-M1, and GST-P1 in 1002 subjects (502 BC patients and 500 disease-free women). PCR-RFLP was employed to genotype the mono-nucleotide variation in CYP1A1, NQO1, and GST-P1, and allele-specific PCR was used to detect the deletion polymorphism in GST-T1 and GST-M1 genes.

RESULTS

Regarding CYP1A1-M1 polymorphism, the heterozygous TC and mutant CC genotype conferred 1.47-fold (95% CI 1.13-1.91, p = 0.004) and 1.84-fold (95% CI 1.17-2.91, p = 0.009) elevated risk of BC. GST-T1 null genotype was associated with increased BC risk (OR 1.47; 95% CI 1.02-2.11, p = 0.037). For the NQO1 C609T variant, the mutant T allele was associated with BC risk with an odds ratio of 1.22 (95% CI 1.02-1.48, p = 0.034). Combinatorial analysis indicated that the presence of NQO1*2 (CT), CYP1A1-M1 (CC), and GST-P1 rs1695 (AG) genotypes conferred 16.7-fold elevated risk of BC (95% CI 3.65-76.85; p < 0.001). Moreover, GST-M1 null genotype was associated with the development of larger primary breast tumors.

CONCLUSION

Xenobiotic-metabolizing gene polymorphisms may play a crucial role in mammary carcinogenesis in South Indian women.

Role of GSTM1 and GSTT1 genotypes in differentiated thyroid cancer and interaction with lifestyle factors: Results from case-control studies in France and New Caledonia

Background

GSTM1 and GSTT1 are involved in detoxification of xenobiotics, products of oxidative stress and in steroid hormones metabolism. We investigated whether GSTM1 and GSTT1 gene deletion was associated with DTC risk and explored interaction with non-genetic risk factors of DTC.

Methods

The study included 661 DTC cases and 736 controls from two case-control studies conducted in France and New Caledonia. Odds ratios (OR) and their confidence interval (CI) for DTC associated with GST genotypes, alcohol drinking, tobacco smoking, body mass index and hormonal factors were calculated using logistic regression models.

Results

Results are presented for Europeans and Melanesians combined, as no heterogeneity between groups was detected. We found that DTC risk increased with obesity and decrease with alcohol drinking. After stratification by gene deletion status, the OR for obesity was 5.75, (95%CI 2.25–14.7) among individuals with GSTT1 and GSTM1-deleted genotype, and 1.26, (95%CI 0.89–1.77) in carriers of both genes (p-interaction = 0.02). The OR for drinking ≥1 glass/week was 0.33 (95%CI 0.15–0.74) in GSTT1-null individuals while it was 1.01 (95%CI 0.67–1.52) in non-null carriers of the gene (p-interaction = 0.01). No interaction between GST genotypes and other non-genetic risk factors was detected.

Conclusion

GSTM1 and GSTT1 genotypes may modulate the DTC risk associated with BMI and alcohol consumption.

Association Of GSTM1, GSTT1 And GSTP1 Polymorphisms With Breast Cancer Among Jordanian Women

Purpose

Genetic predisposition to disease has become one of the most investigated risk factors in recent years, and breast cancer (BC) is no exception. In this study, we investigated specific genetic variants of three candidate genes belonging to the glutathione-S-transferase superfamily that have been implicated in increased risk of cancers.

Materials and methods

This case-control study comprised 241 Jordanian women who were diagnosed with BC in addition to 219 matched controls. Gel electrophoresis of PCR products was used to visualize and genotype both the GSTM1 and GSTT1 genes, while PCR-RFLP was employed to genotype the rs1695 of the GSTP1 gene.

Results

Our findings did not reveal any correlation between the investigated polymorphisms of GST genes and BC risk among Jordanian women. Otherwise, the combination of GSTM1 entire gene deletion and (GG) genotype of GSTP1 polymorphism (rs1695) was significantly associated with BC with p-value <0.05 (i.e. p-value was not significant after correcting for multiple comparison).

Conclusion

We suggest that the interaction between GSTM1 polymorphism and rs1695 of GSTP1 may influence BC development and progression among Jordanian women. More epidemiological studies are needed to provide a baseline for the underlying role of GSTs polymorphisms in tumorigenesis.

Association of GSTM1, GSTT1, GSTM3, and GSTP1 Genes Polymorphisms with Susceptibility to Osteosarcoma: a Case- Control Study and Meta-Analysis

Background: Some studies have investigated the association of GSTM1, GSTT1, GSTM3, and GSTP1 polymorphisms with susceptibility to osteosarcoma; however, these studies results are inconsistent and inconclusive. In order to drive a more precise estimation, the present case-control study and meta-analysis was performed to investigate association of GSTM1, GSTT1, GSTM3, and GSTP1 polymorphisms with osteosarcoma. Methods: Eligible articles were identified by a search of several electronic databases for the period up to May 5, 2018. Odds ratios were pooled using either fixed-effects or random effects models. Results: Finally, a total of 24 case-control studies with 2,405 osteosarcoma cases and 3,293 controls were included in the present meta-analysis. Overall, significantly increased osteosarcoma risk was found when all studies were pooled into the meta-analysis of GSTT1 (Null vs. Present: OR= 1.247 95% CI 1.020-1.524, P= 0.031) and GSTP1 polymorphism (B vs. A: OR= 8.899 95% CI 2.722-29.094, P≤0.001). In the stratified, significantly increased osteosarcoma risk was observed for GSTT1 polymorphism among Asians (Null vs. Present: OR= 1.300 95% CI 1.034-1.635, P= 0.025), but not among Caucasians. Conclusions: This meta-analysis demonstrated that GSTP1 and GSTT1 null genotype are associated with the risk of osteosarcoma. Future large welldesigned epidemiological studies are warranted to validate our results.

Combined effects of GSTM1 and GSTT1 polymorphisms on breast cancer risk: A MOOSE-compliant meta-analysis and false-positive report probabilities test

Many molecular epidemiology studies have reported an association between the combined effects of glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) polymorphisms on breast cancer risk. However, the results have been controversial.A meta-analysis was performed to clarify this issue.Meta-analysis of observational studies in epidemiology guidelines was used. Pooled the crude odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model or fixed-effects model. Several subgroup analyses were conducted by ethnicity, source of control, matching, and menopausal status. In addition, we also performed sensitivity analysis and publication bias. Moreover, a false-positive report probability (FPRP) test was applied to assess positive results.A significantly increased breast cancer risk was observed in overall population (GSTM1 null/GSTT1 present [- +] vs GSTM1 present/GSTT1 present [+ +]: OR = 1.19, 95% CI: 1.03-1.36, GSTM1 null/GSTT1 null [- -] vs + +: OR = 1.63, 95% CI: 1.29-2.06, (- +) + GSTM1 present/GSTT1 null (+ -) vs + +: OR = 1.17, 95% CI: 1.05-1.31, (- +) + (+ -) + (- -) vs + +: OR = 1.27, 95% CI: 1.12-1.44, and - - vs (- +) + (+ -) + (+ +): OR = 1.39, 95% CI: 1.17-1.66) and several subgroup analyses, such as Caucasians, Indians, postmenopausal women, and so on. However, positive results were only considered noteworthy in overall population (- - vs + +: FPRP = 0.150 and (- +) + (+ -) + (- -) vs + +: FPRP = 0.162). Moreover, no significant association was observed when we used the trim and fill method to adjust the pooled data from all populations. Further, none of positive results of sensitivity analysis were considered noteworthy (FPRP >0.2).These positive findings should be interpreted with caution and indicate that an increased breast cancer risk may most likely result from false-positive results, rather than from true associations or biological factors on the combined effects of GSTM1 and GSTT1. Future studies should be based on sample sizes well-powered and attention needs to be paid to study design to further identify this issue.

Female breast cancer and alcohol consumption: a review of the literature

CONTEXT

Consumption of alcoholic beverages is one of the single most important known and modifiable risk factor for human cancer. Among women, breast cancer is the most common cancer worldwide and the leading cause of cancer-related mortality. Consumption of alcoholic beverages is causally associated with female breast cancer and the association shows a linear dose-response relationship. The role of heavy drinking has been long recognized and even a moderate intake is associated with an increased risk for breast cancer. The present review is an update of the current evidence on the association between alcohol consumption and breast cancer risk. The aim is to gain further insight into this association and to improve our current understanding of the effects of the major modifying factors.

EVIDENCE ACQUISITION

Epidemiologic and experimental studies published since the most recent International Agency for Research on Cancer (IARC) Monograph on alcoholic beverages were identified in PubMed using a combination of keywords such as alcohol, breast cancer, polymorphisms, menopausal status.

EVIDENCE SYNTHESIS

Cumulative lifetime consumption, drinking frequency, drinking patterns and timing of exposure each modulate the association between alcohol consumption and breast cancer. Hormonal status, genetic polymorphisms, and nutritional factors may interact with ethanol metabolism and further influence breast cancer risk.

CONCLUSIONS

Better standardization among experimental and epidemiologic designs in assessing alcohol intake and timing of exposure may improve our understanding of the heterogeneity observed across studies, possibly allowing the quantification of the effects of occasional heavy drinking and the identification of a window of higher susceptibility to breast cancer development.

Further studies on the potential contribution of acetaldehyde accumulation and oxidative stress in rat mammary tissue in the alcohol drinking promotion of breast cancer

There is available evidence supporting a positive association between alcohol intake and risk of breast cancer. However, there is limited information regarding possible mechanisms for this effect. Past studies from our laboratory suggest that acetaldehyde accumulation in mammary tissue after alcohol intake may be of particular relevance and that cytosolic and microsomal in situ bioactivation of ethanol to acetaldehyde and free radicals and the resulting stimulation of oxidative stress could be a significant early event related to tumor promotion. In the present studies repetitive alcohol drinking for 28 days was found to produce significant decreases in the mammary tissue content of GSH and alpha tocopherol and in glutathione S-transferase or glutathione reductase activities. In contrast, glutathione peroxidase activity was slightly increased. Malondialdehyde determinations did not show the occurrence of lipid peroxidation while the xylenol orange procedure gave positive results. The mammary microsomal metabolism of ethanol to acetaldehyde was not induced after an acute dose of ethanol or acetone able to induce the activity of its liver counterpart. The cytosolic pathway of alcohol metabolism instead was significantly enhanced by these two treatments. No increased generation of comet images was found either in mammary tissue or in liver under the experimental conditions tested. Results suggest that, while acetaldehyde accumulation in mammary tissue could be a critical event resulting from increasing production of acetaldehyde in situ plus an additional amount of it arriving via blood, other factors such as poor handling of the accumulated acetaldehyde could be also relevant.

Inhibition of rat mammary microsomal oxidation of ethanol to acetaldehyde by plant polyphenols

We previously reported that the microsomal fraction from rat mammary tissue is able to oxidize ethanol to acetaldehyde, a mutagenic-carcinogenic metabolite, depending on the presence of NADPH and oxygen but not inhibited by carbon monoxide or other cytochrome P450 inhibitors. The process was strongly inhibited by diphenyleneiodonium, a known inhibitor of NADPH oxidase, and by nordihydroguaiaretic acid, an inhibitor of lipoxygenases. This led us to suggest that both enzymes could be involved. With the purpose of identifying natural compounds present in food with the ability to decrease the production of acetaldehyde in mammary tissue, in the present studies, several plant polyphenols having inhibitory effects on lipoxygenases and of antioxidant nature were tested as potential inhibitors of the rat mammary tissue microsomal pathway of ethanol oxidation. We included in the present screening study 32 polyphenols having ready availability and that were also tested against the rat mammary tissue cytosolic metabolism of ethanol to acetaldehyde. Several polyphenols were also able to inhibit the microsomal ethanol oxidation at concentrations as low was 10-50 μM. The results of these screening experiments suggest the potential of several plant polyphenols to prevent in vivo production and accumulation of acetaldehyde in mammary tissue.

GSTT1 and GSTP1 polymorphisms and breast cancer risk: a meta-analysis

Cytosolic glutathione S-transferase comprises multiple isoenzymes; studies have principally examined mu-1 (GSTM1: null/present), theta-1 (GSTT1: null/present) and pi-1 (GSTP1 Ile105Val) gene polymorphisms concerning breast cancer risk. Regarding GSTT1 and GSTP1 polymorphisms, studies remain controversial and no recent meta-analysis has appeared. This meta-analysis aims to examine whether GSTT1 and GSTP1 polymorphisms are associated with breast cancer risk. Separate analyses were performed on Chinese and non-Chinese populations, in an attempt to investigate race-specific effects. Eligible articles were identified by a search of MEDLINE bibliographic database for the period up to August 2009. Regarding GSTT1 null/present genotype, 41 case-control studies were eligible (16,589 breast cancer cases and 19,995 controls); 30 case-control studies were eligible for GSTP1 Ile105Val (16,908 cases and 20,016 controls). Pooled odds ratios (ORs) were appropriately derived from fixed-effects or random-effects models. At the overall analysis, the null GSTT1 genotype was associated with elevated breast cancer risk (pooled OR = 1.114, 95% CI: 1.035-1.199, random effects). However, the association seemed confined to non-Chinese populations (33 studies, pooled OR = 1.128, 95% CI: 1.042-1.221, random effects), given that the association was not significant in the subset of Chinese studies (eight studies, pooled OR = 1.061, 95% CI: 0.875-1.286, random effects). Regarding GSTP1 Ile105Val, no statistically significant associations were detected in non-Chinese populations (25 studies). On the other hand, the GG genotype was associated with increased breast cancer risk in Chinese populations (five studies, pooled OR = 1.297, 95% CI: 1.023-1.645, fixed effects); accordingly, the recessive model yielded statistically significant results (pooled OR = 1.273, 95% CI: 1.006-1.610, fixed effects). In conclusion, polymorphisms of both GSTT1 and GSTP1 genes seem associated with elevated breast cancer risk in a race-specific manner. Given the small number of Chinese studies, the finding on GSTP1 Ile105Val merits further investigation.

Do single nucleotide polymorphisms in xenobiotic metabolizing genes determine breast cancer susceptibility and treatment outcomes?

SNPs in CYP1A1, CYP2A1, CYP2B6, CYP2C, CYP2D6, CYP3A, GSTM1, GSTT1, GSTP1, SULT1A1, SULT1A2, UGT, and MTHFR are associated with breast cancer susceptibility; however, lack of such associations are also reported in some populations. The contradictory findings are explained on the basis of ethnic variation among populations and due to lack of proper sample size, detailed genotype-phenotype combinations and validation of gene expression studies at protein level. In this review, SNPs in these genes that have tremendous potential in identification of susceptible individuals, development of preventive strategies, treatment outcomes and their limitations are discussed.

Polymorphism of glutathione S-transferase Omega gene: association with risk of childhood acute lymphoblastic leukemia

PURPOSE

To evaluate the association between glutathione S-transferase Omega (GSTO) genes polymorphism and the susceptibility of acute lymphoblast leukemia (ALL).

METHODS

The polymorphism of GSTO1 and GSTO2 genes were analyzed in 99 ALL patients compared with 100 healthy children by PCR-based restriction fragment length polymorphism (RFLP) analysis.

RESULTS

GSTO1*A140D polymorphism was significantly associated with susceptibility to ALL (OR = 2.24, 95% CI = 1.16-4.35, P = 0.009) whereas, GSTO2*N142D genotype was significantly interacted with high risk group of childhood ALL (OR = 5.52, 95% CI = 1.72-17.71, P = 0.004).

CONCLUSION

This study revealed gene polymorphism in glutathione S-transferase Omega class may be a risk factor to the development of acute childhood lymphoblastic leukemia.

Acetaldehyde accumulation in rat mammary tissue after an acute treatment with alcohol

Previous studies reported the presence in rat mammary tissue of a cytosolic xanthine oxidoreductase pathway for the metabolism of alcohol to acetaldehyde and hydroxyl radicals and to the microsomal biotransformation of ethanol to acetaldehyde. It was also reported that after chronic ethanol drinking stressful oxidative conditions can be observed. The present work reports that even after single doses of ethanol, given at three different levels (6.3 g kg(-1); 3.8 g kg(-1) or 0.6 g kg(-1) p.o.), acetaldehyde accumulates for prolonged periods of time in the mammary tissue to reach concentrations higher than in blood (e.g. 5.1+/-1.2 nmol g(-1) versus 0.2+/-0.1 nmol ml(-1), for 6.3 g kg(-1) dose, 6 h after intoxication). The presence in rat mammary tissue of low activities of additional enzymes able to generate acetaldehyde was established (alcohol dehydrogenase: 0.97+/-0.84 mU mg(-1) protein; CYP2E1: 1.30+/-0.12 x 10(-2) pmol 4-nitrocatechol min(-1) mg(-1) protein) and a low activity of aldehyde dehydrogenase was observed in the cytosolic, mitochondrial and microsomal fractions (0.02+/-0.04; 0.35+/-0.09 and 0.72+/-0.19 mU mg(-1) protein, respectively). After a single high dose of ethanol, an increased susceptibility to oxidative stress was observed, as evidenced by changes in the shape of t-butylhydroperoxide induced emission of chemiluminescence in mammary tissue (6.3 g kg(-1) dose; at 3 and 6 h). In summary, the results show that even after single doses of ethanol, acetaldehyde, either formed in situ or arriving via blood, tends to accumulate in mammary tissue and that this condition might decrease cell defenses against injury.

Polymorphisms in CYP1B1, GSTM1, GSTT1 and GSTP1, and susceptibility to breast cancer

Polymorphisms in the cytochrome P450 1B1 (CYP1B1) and glutathione S-transferase (GST) drug metabolic enzymes, which are responsible for metabolic activation/detoxification of estrogen and environmental carcinogens, were analyzed for their association with breast cancer risk in 541 cases and 635 controls from a North Carolina population. Each polymorphism, altering the catalytic function of their respective enzymes, was analyzed in Caucasian and African-American women. As reported in previous studies, individual polymorphisms did not significantly impact breast cancer risk in either Caucasian or African-American women. However, African-American women exhibited a trend towards a protective effect when they had at least one CYP1B1 119S allele (OR=0.53; 95% CI=0.20-1.40) and increased risk for those women harboring at least one CYP1B1 432V allele (OR=5.52; 95% CI=0.50-61.37). Stratified analyses demonstrated significant interactions in younger (age < or =60) Caucasian women with the CYP1B1 119SS genotype (OR=3.09; 95% CI=1.22-7.84) and younger African-American women with the GSTT1 null genotype (OR=4.07; 95% CI=1.12-14.80). A notable trend was also found in Caucasian women with a history of smoking and at least one valine allele at GSTP1 114 (OR=2.12; 95% CI=1.02-4.41). In Caucasian women, the combined GSTP1 105IV/VV and CYP1B1 119AA genotypes resulted in a near 2-fold increase in risk (OR=1.96; 95% CI=1.04-3.72) and the three way combination of GSTP1 105IV/VV, CYP1B1 119AS/SS and GSTT1 null genotypes resulted in an almost 4-fold increase in risk (OR=3.97; 95% CI=1.27-12.40). These results suggest the importance of estrogen/carcinogen metabolic enzymes in the etiology of breast cancer, especially in women before the age of 60, as well as preventative measures such as smoking cessation.

Glutathione S-transferase M1 and P1 polymorphisms and risk of breast cancer and fibrocystic breast conditions in Chinese women

Enzymes encoded by the glutathione S-tranferase mu 1 (GSTM1) and pi 1 (GSTP1) genes, which are expressed in breast tissue, catalyze the detoxification of endogenous and exogenous electrophiles. Reduced enzyme activity, due to carriage of the GSTM1 deletion or the GSTP1 Ile105Val Val allele, may therefore affect susceptibility to breast cancer and related conditions. In a case-control study of Chinese women, we examined whether these polymorphisms were associated with risk of breast cancer and fibrocystic breast conditions. Women diagnosed with breast cancer (n=615) or fibrocystic breast conditions (n=467) were compared to women without clinical breast disease (n=878). We also examined whether these associations differed by menopausal status or by presence of proliferation in the extra-tumoral epithelium among women with breast cancer and in lesions among women with fibrocystic conditions. No overall association of either GST polymorphism with risk of breast cancer or fibrocystic breast conditions was observed. There was some evidence of slightly elevated cancer risk associated with carriage of the GSTM1 null genotype and at least one GSTP1 105-Val allele (OR=1.33, 95% CI, 0.99-1.80), compared to carriage of the GSTM1 non-null and GSTP1 Ile/Ile genotypes. This relationship was stronger in women who had breast cancer with extra-tumoral tissue proliferation (OR=1.77, 95% CI, 1.03-3.04). Our results suggest that GSTM1 and GSTP1 genotypes do not individually influence susceptibility to breast cancer or fibrocystic breast conditions. The observed increased risk of breast cancer associated with joint carriage of the GSTM1 null genotype and GSTP1 105-Val allele needs confirmation in other studies.

Medical comorbidity and alcohol dependence

Alcohol dependence (AD) and, more generally, alcohol use disorders (AUDs) predispose individuals to adverse consequences that extend beyond the expected damage from alcohol-direct toxicity. Research has shown that the relationship of alcohol use to health outcomes is complex, as is the etiology of AD, and that the individual and social costs of alcohol-related problems are increasing. We review advances in alcohol science that explore the role of alcohol consumption and patterns of drinking in a range of medically comorbid conditions. Although new knowledge can assist in the development of appropriate medical management strategies, AUDs account for an important percentage of the global burden of disease and require approaches that are not uniquely focused on the identification and treatment of AD.

Lipid peroxidation, oxidative stress genes and dietary factors in breast cancer protection: a hypothesis

We have recently proposed that lipid peroxidation may be a common mechanistic pathway by which obesity and hypertension lead to increased renal cell cancer risk. During this exercise, we noted a risk factor swap between breast and kidney cancer (oophorectomy and increased parity, detrimental for kidney, beneficial for breast; high blood pressure, detrimental for kidney, beneficial for breast when it occurs during pregnancy; alcohol, beneficial for kidney, detrimental for breast, and so on). We have subsequently proposed the hypothesis that lipid peroxidation represents a protective mechanism in breast cancer, and reviewed the evidence of the role of lipid peroxidation on established hormonal and non-hormonal factors for breast cancer. Here, we review the evidence in support of lipid peroxidation playing a role in the relationships between dietary factors and breast cancer. Available evidence implicates increased lipid peroxidation products in the anti-carcinogenic effect of suspected protective factors for breast cancer, including soy, marine n-3 fatty acids, green tea, isothiocyanates, and vitamin D and calcium. We also review the epidemiological evidence supporting a modifying effect of oxidative stress genes in dietary factor-breast cancer relationships.

Intervention with polyphenol-rich fruit juices results in an elevation of glutathioneS-transferase P1 (hGSTP1) protein expression in human leucocytes of healthy volunteers

Polyphenols are probably antigenotoxic on account of their antioxidant activities and might alter phase I and II enzymes in a way that results in chemoprotection. We investigated the hypothesis that polyphenols enhance expression of glutathione S-transferases (GSTs), which increases carcinogen detoxification and thereby provides protection against oxidative stress. HGSTP1 protein expression and GST polymorphisms were determined in leucocytes obtained during an intervention study with healthy subjects consuming two fruit juices in an 8 wk trial (polyphenol-free run in phase, juice intervention phase, washout phase, second juice intervention phase, each treatment regime lasted for 2 wk). The study had originally shown that juice intervention significantly reduced oxidative DNA damage in leucocytes at week 8 (Bub, A., Watzl, B., Blockhaus, M., Briviba, K. et al., J. Nutr. Biochem. 2003, 14, 90-98). We reanalysed the levels of DNA damage based on GST genotypes. We also treated leucocytes in vitro with mixtures of polyphenols and determined cytotoxicity and expression of 96 genes related to drug metabolism. Key results with leucocytes of the intervention study were that the initial content of hGSTP1 protein was first suppressed at weeks 4 and 6. At week 8, however, hGSTP1 protein expression was significantly increased. HGSTP1 protein levels and DNA damage were inversely correlated (p = 0.005), but there was no difference for cells obtained from subjects with hGSTM1*1 and hGSTM1*0 genotypes, nor was there any difference between cells from subjects consuming the two different juices. The treatment of leucocytes with polyphenol mixtures in vitro did not result in modulated GST gene expression or total GST activity, but in an up-regulation of other biotransformation enzymes (e. g., members of the cytochrome P450 and the sulphotransferase family). In conclusion, in vitro treatment of leucocytes led to a modulated mRNA expression of selected genes, not directly related to oxidative defence systems. In vivo, however, we observed a delayed enhancement of hGSTP1, which could be associated with an initial repression of oxidative DNA damage in leucocytes from human subjects, consuming juices with high levels of polyphenols.

Is the association between cigarette smoking and breast cancer modified by genotype? A review of epidemiologic studies and meta-analysis

Epidemiologic studies have examined the association between cigarette smoking and breast cancer risk according to genotype with increasing frequency, commensurate with the growing awareness of the roles genes play in detoxifying or activating chemicals found in cigarette smoke and in preventing or repairing the damage caused by those compounds. To date, approximately 50 epidemiologic studies have examined the association between smoking and breast cancer risk according to variation in genes related to carcinogen metabolism, modulation of oxidative damage, and DNA repair. Some of the findings presented here suggest possible effect modification by genotype. In particular, 14 epidemiologic studies have tended to show positive associations with long-term smoking among NAT2 slow acetylators, especially among postmenopausal women. Summary analyses produced overall meta-relative risk (RR) estimates for smoking of 1.2 [95% confidence interval (95% CI), 1.0-1.5] for rapid acetylators and 1.5 (95% CI, 1.2-1.8) for slow acetylators. After stratification by menopausal status, the meta-RR for postmenopausal slow acetylators was 2.4 (95% CI, 1.7-3.3), whereas similar analyses for the other categories showed no association. In addition, summary analyses produced meta-RRs for smoking of 1.1 (95% CI, 0.8-1.4) when GSTM1 was present and 1.5 (95% CI, 1.1-2.1) when the gene was deleted. Overall, however, interpretation of the available literature is complicated by methodologic limitations, including small sample sizes, varying definitions of smoking, and difficulties involving single nucleotide polymorphism selection, which likely have contributed to the inconsistent findings. These methodologic issues should be addressed in future studies to help clarify the association between smoking and breast cancer.

Alcohol dehydrogenase 3, glutathione S-transferase M1 and T1 polymorphisms, alcohol consumption and hepatocellular carcinoma (Italy)

OBJECTIVE

The aim of this study was to investigate the role of alcohol dehydrogenase type 3 (ADH3), glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) polymorphisms in modifying hepatocellular carcinoma (HCC) risk according to alcohol intake.

METHODS

A hospital-based case-control study was conducted in two areas of North Italy. Two-hundred cases hospitalized for HCC and 400 controls were recruited. Genotypes were determined using PCR and the PCR/restriction fragment length polymorphism-based method.

RESULTS

There was no association of the putative risk genotypes ADH3(1-1), GSTM1 null and GSTT1 null with HCC (odds ratio [OR], 0.8; 95% confidence interval [CI], 0.5-1.3; OR, 1.0; 95% CI, 0.6-1.5; OR, 0.8; 95% CI, 0.4-1.4, respectively). A steady increase in HCC risk with increasing alcohol intake, which did not vary according to ADH3 and GSTT1 genotypes, was observed. Nevertheless, the OR for HCC due to an alcohol intake of >100 g of ethanol per day increased in subjects with GSTM1 null genotype (OR, 8.5; 95% CI, 3.9-18.6) compared to GSTM1 non-null genotype (OR, 4.5; 95% CI, 2.0-10.0).

CONCLUSIONS

ADH3(1-1) and GSTT1 null genotypes did not modify the risk of HCC due to alcohol intake whereas an influence of GSTM1 null genotype for high ethanol consumption was suggested.

National Institute on Alcohol Abuse and Alcoholism Report on Moderate Drinking

In support of the 2005 update of the U.S. Department of Agriculture/U.S. Department of Health and Human Services Dietary Guidelines, the National Institute on Alcohol Abuse and Alcoholism was asked to assess the strength of the evidence related to health risks and potential benefits of moderate alcohol consumption, with particular focus on the areas of cardiovascular disease, breast cancer, obesity, birth defects, breastfeeding, and aging. The findings were reviewed by external researchers with extensive research backgrounds on the consequences and benefits of alcohol consumption. This report now serves as the National Institutes of Health's formal position paper on the health risks and potential benefits of moderate alcohol use.

Ethanol-induced oxidative stress and acetaldehyde formation in rat mammary tissue: potential factors involved in alcohol drinking promotion of breast cancer

Recent studies from our laboratory provided evidence that part of the carcinogenic effects of ethanol consumption might be related to its in situ metabolism at cytosolic and microsomal levels, to the mutagen acetaldehyde and to hydroxyl and 1-hydroxyethyl radicals. In this work, we report on our experiments where Sprague-Dawley female rats were exposed to the standard Lieber & De Carli diet for 28 days. We observed: the induction of the (xanthineoxidoreductase mediated) cytosolic and microsomal (lipoxygenase mediated) pathways of ethanol metabolism; promotion of oxidative stress as shown by increased formation of lipid hydroperoxides; delay in the t-butylhydroperoxide induced chemiluminiscence, and a significant decrease in protein sulfhydryls. In addition, the epithelial cells showed ultrastructural alterations consisting of markedly irregular nuclei, with frequent invaginations at the level of the nuclear envelope, condensation of chromatin around the inner nuclear membrane, and marked dilatation of the nuclear pores showing filamentous material exiting to the cytoplasm. In conclusion, the presence in mammary epithelial cells of cytosolic and microsomal pathways of ethanol bioactivation to carcinogenic and to tumorigenic metabolites might play a role in alcohol promotion of breast cancer.

Role of Lipid Peroxidation in the Epidemiology and Prevention of Breast Cancer

We have recently proposed a common mechanistic pathway by which obesity and hypertension lead to increased renal cell cancer risk. Our hypothesis posits lipid peroxidation, which is a principal mechanism in rodent renal carcinogenesis, as an intermediate step that leads to a final common pathway shared by numerous observed risks (including obesity, hypertension, smoking, oophorectomy/hysterectomy, parity, preeclampsia, diabetes, and analgesics) or protective factors (including oral contraceptive use and alcohol) for renal cell cancer [Cancer Causes Control 2002;13:287-93]. During this exercise, we have noticed how certain risk factors for renal cell carcinoma are protective for breast cancer and how certain protective factors for renal cell carcinoma increase risk for breast cancer. Parity and oophorectomy, for example, are positively associated with renal cell carcinoma but are negatively associated with breast cancer. Similarly, obesity and hypertension are positively associated with renal cell carcinoma, but obesity is negatively associated with breast cancer in premenopausal women and hypertension during pregnancy is negatively associated with breast cancer. Furthermore, alcohol intake, negatively associated with renal cell carcinoma, is also positively associated with breast cancer. We propose here the possibility that lipid peroxidation may represent a protective mechanism in breast cancer. Although this runs counter to the conventional view that lipid peroxidation is a process that is harmful and carcinogenic, we present here the chemical and biological rationale, based on epidemiologic and biochemical data, which may deserve further consideration and investigation.

Nutrition and primary prevention of breast cancer: foods, nutrients and breast cancer risk

Worldwide, each year approximately one million women are newly diagnosed with breast cancer (BC), in Germany 65 new cases per 100,000 inhabitants are registered, yearly. The fact that incidence has been rising in parallel with economic development indicates that environmental factors might play a role in the causation of BC. Migrational data have pointed to nutrition as one of the more relevant external factors involved. Preventive dietary advice often includes a reduction of alcohol, red meat and animal fat and increasing the intake of vegetables, fruit and fibre and lately, phyto-estrogens from various sources. Clearly, the scientific basis for these recommendations appears sparse. The available prospective data from epidemiological studies and interventional trials do not support the overall hypothesis that higher fat-intakes are a relevant risk factor for BC development, more important seems the relative distribution of various fatty acids. A non-vegetarian eating habit (consumption of animal products) per se does not elevate BC risk, while consumption of broiled or deep fried meats cannot be ruled out as a risk factor in genetically susceptible individuals. It appears prudent to abstain from regular and increased alcohol consumption. This should be particularly true for pubescent girls, in whom glandular breast tissue is particularly vulnerable. In general, if alcohol is consumed on a regular basis, a sufficient supply of fresh vegetables and fruit is essential. While there is no overall protective effect of a high fruit and vegetable consumption speculation remains over possible beneficial effects of certain subcategories, especially brassica vegetables like broccoli, cauliflower and cabbage. In essence, regional differences in BC incidence are probably partially attributable to life long dietary habits. There is no need to adopt a foreign dietary plan in order to protect oneself against BC. Traditional western diets also have their beneficial ingredients that should be regular constituents in our meals. Lignans from traditionally made sourdough rye bread, linseed/flaxseed and berries are local sources of potentially canceroprotective phyto-estrogens. Furthermore, indole-3-carbinol rich cabbage species might contribute to BC protection by diet. Nevertheless, clear cut recommendations for or against single nutrients or secondary plant metabolites are not yet possible, lacking sufficient data on individual bioavailability, safety and long term outcome. BC prevention by dietary means therefore relies on an individually tailored mixed diet, rich in basic foods and traditional manufacturing and cooking methods.

Relationship among metabolizing genes, smoking and alcohol used as modifier factors on prostate cancer risk: exploring some gene-gene and gene-environment interactions

BACKGROUND

Prostate cancer (PCa) is one of the most common male cancers, but the burden of this disease shows remarkable worldwide variation. The role of susceptibility low penetrance genes and environmental factors in the etiology of (PCa) is unclear, but may involve, in some cases, multiple alleles at multiple loci and environmental factors.

STUDY OBJECTIVES

To assess whether CYP1A1, GSTM1, GSTT1 susceptibility genotypes, smoking status and alcohol consumption factors contribute to PCa risk, gene-gene and gene-environment interactions were analyzed.

DESIGN AND PARTICIPANTS

We explored interactions on a multiplicative scale conducting a population-based case-control and a case-only study on 103 incident PCa patients and 132 unrelated controls.

MAIN RESULTS

The interaction odds ratios (IOR) for PCa risk were increased in men who had both susceptibility genotypes GST (M1; T1) null and CYP1A1-M1* in a case-control and case-only design (IOR(cc): 1.11; 95% CI: 0.12-10.02; IOR(cc): 6.23; 95%, CI: 0.51-75.89; IOR(co): 2.80; 95% CI: 0.44-17.45 and IORco: 2.65; 95%, CI: 0.30-25.40). No clear evidence for interaction on a multiplicative scale between smoking status, alcohol consumption and genetic polymorphisms in PCa risk was observed.

CONCLUSIONS

Our findings suggest that the interaction between genetic polymorphisms in GST (T1; M1) and CYP1A1-M1* would play a significant role as a modifying factor on PCa risk in Chilean people. However, these preliminary exploratory results should be confirmed in a larger study.

Association of the NAD(P)H: quinone oxidoreductase C609T polymorphism and the risk of cervical cancer in Japanese subjects

OBJECTIVE

In this study, genetic polymorphisms, NQO1 C609T, GSTM1 positive/null, and GSTT1 positive/null, were examined with reference to cervical cancer risk in a population-based incident case-control study in Japanese.

METHODS

The cases comprised 131 cervical cancer patients: 87 cases with squamous cell carcinoma (SCC) and 44 with adenocarcinoma (ADC) or adenosquamous carcinoma (ADSC). Controls were sampled from 320 healthy women who underwent a health checkup.

RESULTS

The cervical cancer risk was substantially elevated with smoking for all cases, SCC cases, and ADC/ADSC cases (OR = 4.50, 95% CI = 2.48-8.17, P < 0.001; OR = 5.68, 95% CI = 2.99-10.78, P < 0.001; and OR = 2.57, 95% CI = 1.09-6.08, P = 0.032; respectively). The frequency of the NQO1 609TT genotype, reported to be associated with null enzyme activity, was higher in individuals with all cases and SCC than in the healthy controls (OR = 1.97, 95% CI = 1.06-3.66, P = 0.032; and OR = 2.42, 95% CI = 1.21-4.82, P = 0.012; respectively), but not in ADC/ADSC cases. Analysis of polymorphisms for GSTM1 and GSTT1 showed no significant differences between cervical cancer patients and controls. In stratification analysis, significant elevated risk of all cases and SCC was associated with the NQO1 609TT genotype among nonsmokers (OR = 2.15, 95% CI = 1.08-4.30, P = 0.030; and OR = 2.83, 95% CI = 1.21-6.31, P = 0.011; respectively), but not smokers. No gene-gene interaction was observed in our case subjects.

CONCLUSION

This is the first report that the NQO1 gene might be important in relation to the risk of squamous cell carcinoma of the cervix.

Alcohol and public health

Alcoholic beverages, and the problems they engender, have been familiar fixtures in human societies since the beginning of recorded history. We review advances in alcohol science in terms of three topics: the epidemiology of alcohol's role in health and illness; the treatment of alcohol use disorders in a public health perspective; and policy research and options. Research has contributed substantially to our understanding of the relation of drinking to specific disorders, and has shown that the relation between alcohol consumption and health outcomes is complex and multidimensional. Alcohol is causally related to more than 60 different medical conditions. Overall, 4% of the global burden of disease is attributable to alcohol, which accounts for about as much death and disability globally as tobacco and hypertension. Treatment research shows that early intervention in primary care is feasible and effective, and a variety of behavioural and pharmacological interventions are available to treat alcohol dependence. This evidence suggests that treatment of alcohol-related problems should be incorporated into a public health response to alcohol problems. Additionally, evidence-based preventive measures are available at both the individual and population levels, with alcohol taxes, restrictions on alcohol availability, and drinking-driving countermeasures among the most effective policy options. Despite the scientific advances, alcohol problems continue to present a major challenge to medicine and public health, in part because population-based public health approaches have been neglected in favour of approaches oriented to the individual that tend to be more palliative than preventative.

Glutathione S-transferases M1, T1, and P1 and Breast Cancer: A Pooled Analysis

The glutathione S-transferase (GST) genes are involved in the metabolism of various carcinogens. Deletion polymorphisms in the genes GSTM1 and GSTT1 and a base transition polymorphism at codon 105 (Ile→Val) in GSTP1 were investigated in relation to breast cancer risk. Tobacco smoking and reproductive factors were examined as potential effect modifiers. Individual data from seven case-control studies were pooled within the International Collaborative Study on Genetic Susceptibility to Environmental Carcinogens. To measure the effect of GSTs on breast cancer risk, odds ratios and 95% confidence intervals were computed adjusting for study center and age. The modifying effect was investigated by stratification on variables of smoking habits and reproductive history. A total of 2,048 cases with breast cancer and 1,969 controls were analyzed. The relative odds ratio (95% confidence interval) of breast cancer was 0.98 (0.86–1.12) with the GSTM1 null, 1.11 (0.87–1.41) with the GSTT1 null, 1.01 (0.79–1.28) with GSTP1 heterozygous mutants, and 0.93 (0.62–1.38) with GSTP1 homozygous mutants. Stratification by smoking or reproductive factors did not reveal a modifying effect of these variables, nor was there any association between GSTM1 and age at diagnosis of breast cancer. This is the largest study investigating susceptibility to breast cancer due to polymorphisms in the GST genes. The results conclusively show that single gene GST polymorphisms do not confer a substantial risk of breast cancer to its carriers. Furthermore, GSTs did not interact with smoking or reproductive history to modify cancer risk.

A strategy for cancer prevention: Stimulation of the Nrf2-ARE signaling pathway

Many genes, with products involved in the protection of cells against carcinogens, oxidants, and other toxic chemicals, are under the transcriptional control of a simple DNA regulatory element [i.e., the antioxidant response element (ARE)]. One or more functional AREs have been confirmed or are believed to exist in the upstream region of many anticarcinogenic/antioxidant genes and have been shown to mediate the coordinate transcriptional up-regulation of these genes by many chemical agents [i.e., the ARE-mediated inducers]. There is strong evidence that increased expression of ARE-regulated genes inhibits cancer development. The signaling system leading to ARE activation has been partly elucidated, and nuclear factor erythroid 2–related factor 2 (Nrf2) has been identified as the key transcriptional factor that serves to transmit the inducer signal to ARE. It is now known that nuclear factor erythroid 2–related factor 2, which is normally sequestered in the cytoplasm by Kelch-like ECH-associated protein 1, dissociates from Kelch-like ECH-associated protein 1 on exposure to ARE-mediated inducers, translocates to the nucleus, complexes with other nuclear factors, and binds to ARE. Rapid and simple assays have been devised to identify chemical agents that can stimulate this signaling pathway. Moreover, many ARE-mediated inducers have been identified, and several of them have shown promising cancer preventive activity.

Genetic polymorphisms in GSTM1, GSTP1, and GSTT1 and the risk for breast cancer: results from the Shanghai Breast Cancer Study and meta-analysis

PURPOSE

We studied the relation of breast cancer to common deletion mutations in GSTM1 and GSTT1 and the functional Ile(105)Val polymorphism in GSTP1 in a large, population-based case-control study conducted in China and performed a meta-analysis to summarize the literature.

EXPERIMENTAL DESIGN

In the case-control study, a total of 1144 breast cancer cases and 1221 community controls were genotyped for GSTM1, GSTP1, and GSTT1 using PCR-based methods. Associations of genotypes and breast cancer were evaluated in logistic regression models. Meta-analysis odds ratios (ORs) were estimated using a fixed effects model.

RESULTS

In the case-control study, associations were null for GSTM1 [age-adjusted OR 0.97, 95% confidence interval (CI): 0.82-1.14] and GSTT1 (OR 0.97, 95% CI: 0.83-1.15). A significant increase in risk was observed among homozygotes for the variant Ile(105)Val polymorphism (OR 1.92, 95% CI: 1.21-3.04). No combined effects of GSTM1, GSTP1, and GSTT1 genotypes or interactions with potential effect modifiers were detected. All results were similar in pre- and postmenopausal women and for early versus advanced stage breast cancer. The meta-analysis, based predominantly on Caucasian women, supported null results for the homozygous deletion variant in GSTM1 (summary OR 1.05; combining 19 studies) and GSTT1 (summary OR 1.11; 15 studies). Meta-analysis results for the homozygous GSTP1 variant indicated no overall association (summary OR 1.04; 10 studies), although results varied significantly across studies (P = 0.009).

CONCLUSIONS

This large case-control study provides strong support for earlier studies showing no overall association of the GSTM1 and GSTT1 deletion polymorphisms with breast cancer risk. The GSTP1 variant may be relevant to breast cancer risk in Asian populations.