Tobacco smoking,GSTP1 polymorphism, and bladder carcinoma

Fruits and vegetables intake and bladder cancer risk: a pooled analysis from 11 case-control studies in the BLadder cancer Epidemiology and Nutritional Determinants (BLEND) consortium

PURPOSE

High consumption of fruits and vegetables decrease the risk of bladder cancer (BC). The evidence of specific fruits and vegetables and the BC risk is still limited.

METHODS

Fruit and vegetable consumptions in relation to BC risk was examined by pooling individual participant data from case-control studies. Unconditional logistic regression was used to estimate study-specific odds ratio's (ORs) with 95% confidence intervals (CIs) and combined using a random-effects model for intakes of total fruits, total vegetables, and subgroups of fruits and vegetables.

RESULTS

A total of 11 case-control studies were included, comprising 5637 BC cases and 10,504 controls. Overall, participants with the highest intakes versus the lowest intakes of fruits in total (OR 0.79; 95% CI 0.68-0.91), citrus fruits (OR 0.81; 95% CI 0.65-0.98), pome fruits (OR 0.76; 95% CI 0.65-0.87), and tropical fruits (OR 0.84; 95% CI 0.73-0.94) reduced the BC risk. Greater consumption of vegetables in total, and specifically shoot vegetables, was associated with decreased BC risk (OR 0.82; 95% CI 0.68-0.96 and OR 0.87; 95% CI 0.78-0.96, respectively). Substantial heterogeneity was observed for the associations between citrus fruits and total vegetables and BC risk.

CONCLUSION

This comprehensive study provides compelling evidence that the consumption of fruits overall, citrus fruits, pome fruits and tropical fruits reduce the BC risk. Besides, evidence was found for an inverse association between total vegetables and shoot vegetables intake.

A data mining approach to investigate food groups related to incidence of bladder cancer in the BLadder cancer Epidemiology and Nutritional Determinants International Study

At present, analysis of diet and bladder cancer (BC) is mostly based on the intake of individual foods. The examination of food combinations provides a scope to deal with the complexity and unpredictability of the diet and aims to overcome the limitations of the study of nutrients and foods in isolation. This article aims to demonstrate the usability of supervised data mining methods to extract the food groups related to BC. In order to derive key food groups associated with BC risk, we applied the data mining technique C5.0 with 10-fold cross-validation in the BLadder cancer Epidemiology and Nutritional Determinants study, including data from eighteen case-control and one nested case-cohort study, compromising 8320 BC cases out of 31 551 participants. Dietary data, on the eleven main food groups of the Eurocode 2 Core classification codebook, and relevant non-diet data (i.e. sex, age and smoking status) were available. Primarily, five key food groups were extracted; in order of importance, beverages (non-milk); grains and grain products; vegetables and vegetable products; fats, oils and their products; meats and meat products were associated with BC risk. Since these food groups are corresponded with previously proposed BC-related dietary factors, data mining seems to be a promising technique in the field of nutritional epidemiology and deserves further examination.

Impact of alcohol consumption on the risk of developing bladder cancer: a systematic review and meta-analysis

BACKGROUND

Epidemiologic studies that investigated alcohol consumption in relation to the risk of bladder cancer (BCa) have demonstrated inconsistent results. We conducted a systematic review and meta-analysis of the literature to investigate the association of alcohol including different types of alcoholic beverages consumption with the risk of BCa.

MATERIALS AND METHODS

A systematic search of Web of Science, Medline/PubMed and Cochrane library was performed in May 2018. Studies were considered eligible if they assessed the risk of BCa due to alcohol consumption (moderate or heavy dose) and different types of alcoholic beverages (moderate or heavy dose) in multivariable analysis in the general population (all genders, males or females) or compared with a control group of individuals without BCa.

STUDY DESIGN

observational cohorts or case-control.

RESULTS

Sixteen studies were included in this meta-analysis. Moderate and heavy alcohol consumption did not increase the risk of BCa in the entire population. Sub-group and sensitivity analyses revealed that heavy alcohol consumption increased significantly the risk of BCa in the Japanese population, RR 1.31 (95% CI 1.08-1.58, P < 0.01) in the multivariable analysis, and in males RR of 1.50 (95% CI 1.18-1.92, P < 0.01), with no significant statistical heterogeneity. Moreover, heavy consumption of spirits drinks increased the risk of BCa in males, RR 1.42 (95% CI 1.15-1.75, P < 0.01).

CONCLUSION

In this meta-analysis, moderate and heavy alcohol consumption did not increase the risk of bladder cancer significantly. However, heavy consumption of alcohol might increase the risk of BCa in males and in some specific populations.

The association between coffee consumption and bladder cancer in the bladder cancer epidemiology and nutritional determinants (BLEND) international pooled study

Background

Inconsistent results for coffee consumption and bladder cancer (BC) risk have been shown in epidemiological studies. This research aims to increase the understanding of the association between coffee consumption and BC risk by bringing together worldwide case–control studies on this topic.

Methods

Data were collected from 13 case–control comprising of 5,911 cases and 16,172 controls. Pooled multivariate odds ratios (ORs), with corresponding 95% confidence intervals (CIs), were obtained using multilevel logistic regression models. Furthermore, linear dose–response relationships were examined using fractional polynomial models.

Results

No association of BC risk was observed with coffee consumption among smokers. However, after adjustment for age, gender, and smoking, the risk was significantly increased for never smokers (ever vs. never coffee consumers: OR_model2 1.30, 95% CI 1.06–1.59; heavy (> 4 cups/day) coffee consumers vs. never coffee consumers: OR_model2 1.52, 95% CI 1.18–1.97, p trend = 0.23). In addition, dose–response analyses, in both the overall population and among never smokers, also showed a significant increased BC risk for coffee consumption of more than four cups per day. Among smokers, a significant increased BC risk was shown only after consumption of more than six cups per day.

Conclusion

This research suggests that positive associations between coffee consumption and BC among never smokers but not smokers.

Modeling the Complex Exposure History of Smoking in Predicting Bladder Cancer: A Pooled Analysis of 15 Case-Control Studies

BACKGROUND

Few studies have modeled smoking histories by combining smoking intensity and duration to show what profile of smoking behavior is associated with highest risk of bladder cancer. This study aims to provide insight into the association between smoking exposure history and bladder cancer risk by modeling both smoking intensity and duration in a pooled analysis.

METHODS

We used data from 15 case-control studies included in the bladder cancer epidemiology and nutritional determinants study, including a total of 6,874 cases and 17,727 controls. To jointly interpret the effects of intensity and duration of smoking, we modeled excess odds ratios per pack-year by intensity continuously to estimate the risk difference between smokers with long duration/low intensity and short duration/high intensity.

RESULTS

The pattern observed from the pooled excess odds ratios model indicated that for a fixed number of pack-years, smoking for a longer duration at lower intensity was more deleterious for bladder cancer risk than smoking more cigarettes/day for a shorter duration. We observed similar patterns within individual study samples.

CONCLUSIONS

This pooled analysis shows that long duration/low intensity smoking is associated with a greater increase in bladder cancer risk than short duration/high intensity smoking within equal pack-year categories, thus confirming studies in other smoking-related cancers and demonstrating that reducing exposure history to a single metric such as pack-years was too restrictive.

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Te increase in the prevalence of arterial hypertension (AH) in populations, ineffective treatment, the need for risk stratifcation, prevention, early diagnosis and successful treatment, actualize genomic studies to develop a personalized therapeutic approach to AH. Te review investigates the possible genetically determined mechanisms of the development of hypertension and endothelial dysfunction caused by polymorphism of the genes of endothelial nitric oxide synthase (eNOS) and enzymes of phases I and II of the xenobiotics detoxifcation system. Te probable interaction of both systems under the influence of harmful environmental factors, including tobacco smoking, and in the gestational period is discussed. It is proposed to study AH candidate genes in the xenobiotics detoxifcation system, the carriage of different variants of which can determine the sensitivity or resistance to antihypertensive pharmacotherapy, which can be useful for developing of the personalized tactics of managing patients with AH.

Detection of CYP1A1 and GSTP1 gene polymorphisms in bladder cancer patients in a Turkish population using a polymerase chain reaction-restriction fragment length polymorphism method

Objective

Understanding genetic polymorphisms might facilitate the analysis of differences between individuals in their susceptibility to developing cancers as a result of environmental carcinogens. Skin, lung, colon and bladder cancers emerge from biological defects in GSTM1, GSTT1 and GSTP1 gene expressions. In this study, we aimed to investigate whether there was an association between CYP1A1 and GSTP1 gene polymorphisms and bladder cancer in a Turkish population.

Material and methods

Blood samples were collected from 120 individuals (60 patients with bladder cancer and 60 healthy individuals), and their DNAs were isolated. A polymerase chain reaction-restriction fragment length polymorphism (PCR - RFLP) method was used to detect the frequencies of CYP1A1 NM_000499.3: c.*1189T > C and GSTP1 NM_000852.3: c.313A > G polymorphisms in bladder cancer patients.

Results

The frequency of the CYP1A1: c.*1189 TC genotype and C allele were significantly different between bladder cancer patients and healthy individuals (p=0.001 and p=0.005, respectively). However, there was no significant difference for the GSTP1: c.313 AG genotype or G allele between both study groups (p=0.699 and p=0.360, respectively).

Conclusion

A polymorphic site of the CYP1A1 gene might be involved in the development of bladder cancer. However, the investigated GSTP1 polymorphic site did not represent an important risk factor for the development of bladder cancer in a Turkish population.

The relationship between GSTA1, GSTM1, GSTP1, and GSTT1 genetic polymorphisms and bladder cancer susceptibility: A meta-analysis

BACKGROUND

Previous studies have investigated the relationship between GSTA1, GSTM1, GSTP1, and GSTT1 polymorphisms and bladder cancer (BCa) susceptibility, respectively, but the results remain inconsistent. So, we conducted this meta-analysis including 79 case-control studies to explore such relationships.

METHODS

We searched PubMed, EMBASE, Cochrane library, Web of Science, and CNKI for relevant available studies. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were implemented to evaluate the intensity of associations. Publication bias was estimated using Begg funnel plots and Egger regression test. To assess the stability of the results, we used sensitivity analysis with the method of calculating the results again by omitting 1 single study each time. Between-study heterogeneity was tested using the I statistic.

RESULTS

No significant association between GSTA1 polymorphism and BCa susceptibility (OR = 1.05, 95% CI 0.83-1.33) was noted. Besides, meaningful association between individuals who carried the GSTM1 null genotype and increased BCa risk was detected (OR = 1.39, 95%CI 1.28-1.51). When stratified by ethnicity, significant difference was found in both Caucasian (OR = 1.39, 95% CI 1.23-1.58) and Asian populations (OR = 1.45, 95% CI 1.31-1.61). Moreover, in the subgroup analysis by source of controls (SOC), the results were significant in both hospital-based control groups (OR = 1.49, 95% CI 1.35-1.64) and population-based control groups (OR = 1.21, 95% CI = 1.07-1.37). Additionally, the analysis revealed no significant association between GSTP1 polymorphism and BCa risk (OR = 1.07, 95% CI 0.96-1.20). What is more, significant associations between GSTT1 polymorphism and BCa susceptibility were discovered (OR = 1.11, 95% CI 1.00-1.22). In the subgroup analysis by ethnicity, significant associations between GSTT1 null genotype and BCa risk were observed only in Caucasians (OR = 1.25, 95% CI 1.09-1.44). Furthermore, when stratified by SOC, no obvious relationship was found between the GSTT1 null genotype polymorphism with hospital-based population (OR = 1.11, 95% CI 0.97-1.28) or population-based population (OR = 1.10, 95% CI 0.96-1.27).

CONCLUSION

This study suggested that GSTM1 null genotype and GSTT1 null genotype might be related to higher BCa risk, respectively. However, no associations were observed between GSTA1 or GSTP1 polymorphisms and BCa susceptibility.

International pooled study on diet and bladder cancer: the bladder cancer, epidemiology and nutritional determinants (BLEND) study: design and baseline characteristics

Background

In 2012, more than 400,000 urinary bladder cancer cases occurred worldwide, making it the 7^th most common type of cancer. Although many previous studies focused on the relationship between diet and bladder cancer, the evidence related to specific food items or nutrients that could be involved in the development of bladder cancer remains inconclusive. Dietary components can either be, or be activated into, potential carcinogens through metabolism, or act to prevent carcinogen damage.

Methods/design

The BLadder cancer, Epidemiology and Nutritional Determinants (BLEND) study was set up with the purpose of collecting individual patient data from observational studies on diet and bladder cancer. In total, data from 11,261 bladder cancer cases and 675,532 non-cases from 18 case–control and 6 cohort studies from all over the world were included with the aim to investigate the association between individual food items, nutrients and dietary patterns and risk of developing bladder cancer.

Discussion

The substantial number of cases included in this study will enable us to provide evidence with large statistical power, for dietary recommendations on the prevention of bladder cancer.

Quantified relations between exposure to tobacco smoking and bladder cancer risk: a meta-analysis of 89 observational studies

BACKGROUND

Smoking is a major risk factor for bladder cancer (BC). This meta-analysis updates previous reviews on smoking characteristics and BC risk, and provides a more quantitative estimation of the dose-response relationship between smoking characteristics and BC risk.

METHODS

In total, 89 studies comprising data from 57 145 BC cases were included and summary odds ratios (SORs) were calculated. Dose-response meta-analyses modelled relationships between smoking intensity, duration, pack-years and cessation and BC risk. Sources of heterogeneity were explored and sensitivity analyses were conducted to test the robustness of findings.

RESULTS

Current smokers (SOR = 3.14, 95% CI = 2.53-3.75) and former smokers(SOR = 1.83, 95% CI = 1.52-2.14) had an increased risk of BC compared with never smokers. Age at first exposure was negatively associated with BC risk. BC risk increased gradually by smoking duration and a risk plateau at smoking 15 cigarettes a day and 50 pack-years was observed. Smoking cessation is most beneficial from 20 years before diagnosis. The population-attributable risk of BC for smokers has decreased from 50% to 43% in men and from 35% to 26% in women from Europe since estimated in 2000. Results were homogeneous between sources of heterogeneity, except for lower risk estimates found in studies of Asian populations.

CONCLUSIONS

Active smokers are at an increased risk of BC. Dose-response meta-analyses showed a BC risk plateau for smoking intensity and indicate that even after long-term smoking cessation, an elevated risk of bladder cancer remains.

Polymorphisms of NRF2 and NRF2 target genes in urinary bladder cancer patients

PURPOSE

NRF2 transcription factor is involved in modulation of various antioxidant and metabolic genes and, therefore, may modulate anti-carcinogenic potential. Association between polymorphisms of NRF2 and five NRF2-regulated genes and urinary bladder cancer (BC) risk was analyzed.

METHODS

The study group included 244 BC patients, while the control group comprised 365 individuals with no evidence of malignancy. Genotyping of GSTM1 (deletion), GSTT1 (deletion), GSTA1 -69C/T (rs3957357), GSTP1 Ile105Val (rs1695), SOD2 Ala16Val (rs4880) and NRF2 -617C/A (rs6721961) in blood genomic DNA was performed by means of real-time PCR assays. The associations between gene polymorphism and BC risk were computed by logistic regression.

RESULTS

The frequency of GSTA1, GSTP1, SOD2 and NRF2 genotypes did not differ in both groups. A significantly higher BC risk was associated with GSTM1 null genotype after adjusting to age, sex and smoking habit (OR 1.85, 95 % CI 1.30-2.62; P = 0.001). GSTT1 null (OR 0.50, 95 % CI 0.31-0.81; P = 0.005) and GSTP1 Val105Val (OR 0.52, 95 % CI 0.27-0.98; P = 0.04) genotypes were associated with reduced BC risk separately or in combination (OR 0.24, 95 % CI 0.11-0.51; P < 0.0001) (P heterogeneity = 0.01). Combined GSTT1 null and SOD2 with at least one 16Val allele among never smokers encompass reduced BC risk (OR 0.14, 95 % CI 0.03-0.63; P = 0.01) (P heterogeneity = 0.04).

CONCLUSIONS

This study supports hypothesis that GSTM1 null genotype may be a moderate BC risk factor. The gene-gene and gene-environment interactions associated with combined GSTP1/GSTT1 and combined GSTT1/SOD2 genetic polymorphisms along with cigarette smoking habit may play a significant role in BC risk modulation.

Are bladder neoplasms more aggresive in patients with a smoking-related second malignancy?

BACKGROUND

Relationships between smoking and bladder neoplasms, one of the common malignancies, are well-known. Different smoking-related malignancies may occur together. In this study, we evaluated the stage and grade of bladder neoplasms in patients also featuring lung or larynx cancer.

MATERIALS AND METHODS

From January 2006 to February 2012, patients who underwent surgery for bladder neoplasms in our clinic were screened retrospectively. In the evaluation, 5 patients had larynx cancer and 20 patients have lung cancer in addition, all having been smoking for a long time. The bladder tumor stage and grade were investigated in these 25 cases.

RESULTS

Mean age of patients was 66.8 (49-78). In the evaulation, all of 5 patients who had larnyx cancer also had high grade urothelial cancer. One had T2 urothelial, and 3 T1 urothelial cancer. In the same way, all of the 20 patients with lung cancer also have high grade urothelial cancer, three T2, and 13 T1. Bladder cancer stage and grade were determined to be significantly increased in patients with concomitant bladder and lung or larynx cancer.

CONCLUSIONS

In the patients who have smoking releated second malignancy, bladder cancer prognosis appears more aggressive. We now need a larger series and multi-center studies for understanding relevant pathophysiology.

GSTA1, GSTM1, GSTP1, and GSTT1 polymorphisms and susceptibility to smoking-related bladder cancer: a case-control study

OBJECTIVES

Glutathione S-transferases (GSTs) are a family of enzymes involved in detoxification. Genes encoding for GSTA1, GSTM1, GSTP1, and GSTT1 proteins are polymorphic, which can result in complete or partial loss of enzyme activity. Previous studies have associated polymorphisms of GSTA1, GSTM1, and GSTP1 genes with a higher risk of bladder cancer, but this is still controversial. Potential role of GSTA1 polymorphism in susceptibility to bladder cancer in Whites is lacking. We examined association between GSTA1, GSTM1, GSTP1, and GSTT1 gene variants and bladder cancer risk and evaluated whether they were modified by smoking.

MATERIALS AND METHODS

A hospital-based case-control study recruited 201 incidence cases and 122 age-matched controls. Deletion polymorphism of GSTM1 and GSTT1 was identified by polymerase chain reaction method. Single nucleotide polymorphism of GSTA1 and GSTP1 was identified by restriction fragment length polymorphism method. Uniconditional multivariate logistic regression was applied to model association between genetic polymorphisms and bladder cancer risk, as well as effect modification by smoking.

RESULTS

No significant difference was observed in the distributions of GSTM1, GSTT1, GSTA1, and GSTP1 gene variants between patients and controls. None of the examined polymorphisms was significantly associated with bladder cancer risk independently. The results of gene-smoking interaction analyses indicated a significant combined effect of smoking and all common GST polymorphisms tested (P for trend = 0.001). However, the most significant effect on bladder cancer risk was observed in smokers carrying lower activity GSTA1-AB/BB and GSTM-null genotype (OR = 3.5, P < 0.05) compared with GSTA1-AA and GSTM1-active non-smokers. Overall, the risk observed did not significantly differ with respect to quantity of cigarettes smoked. However, heavy smokers with GSTM1-null genotype had 2 times higher risk of bladder cancer than GSTM1-null light smokers (OR = 4.8 vs. OR = 2.0) when GSTM1-active non-smokers served as reference group. Smokers carrying both GSTM1-null and GSTA1-AB + BB genotypes exhibited the highest risk of bladder cancer (OR = 2.00, P = 0.123).

CONCLUSIONS

Null or low-activity genotypes of the GSTA1, GSTM1, GSTT1, and GSTP1 did not contribute independently towards the risk of bladder cancer in our patients. However, in association with smoking, both low activity GSTA1 and GSTM1-null genotype increase individual susceptibility to bladder cancer.

GSTP1 gene Ile105Val polymorphism causes an elevated risk for bladder carcinogenesis in smokers

BACKGROUND

The glutathione S transferase (GST) family of enzymes plays a vital role in the phase II biotransformation of environmental carcinogens, pollutants, drugs and other xenobiotics. GSTs are polymorphic and polymorphisms in GST genes have been associated with cancer susceptibility and prognosis. GSTP1 is associated with risk of various cancers including bladder cancer. A case control study was conducted to determine the genotype distribution of GSTP1 A>G SNP, to elucidate the possible role of this SNP as a risk factor in urinary bladder cancer (UBC) development and to examine its correlation with clinico-pathologic variables inUBC cases.

MATERIALS AND METHODS

Using the polymerase chain reaction-restriction fragment length polymorphism (PCR- RFLP) approach, we tested the genotype distribution of 180 bladder cancer patients in comparison with 210 cancer-free controls from the same geographical region with matched frequency in age and gender.

RESULTS

We did not observe significant genotype differences between the control and bladder cancer patients overall with an odds ratio (OR)=1.23 (p>0.05). The rare allele (AG+GG) was found to be present more in cases (28.3%) than in controls (24%), though the association was not significant (p<0.05). However, a significant risk of more than 2-fold was found for the variant allele (AG+GG) with smokers in cases as compared to controls (p>0.05).

CONCLUSIONS

Thus, it is evident from our study that GSTP1 SNP is not implicated overall in bladder cancer, but that the rare, valine-related allele is connected with higher susceptibility to bladder cancer in smokers and also males.

Glutathione S-transferase P1 gene polymorphism and bladder cancer susceptibility: an updated analysis

Studies investigating the association between glutathione S-transferase P1 (GSTP1) gene polymorphism and bladder cancer (BC) risk have reported conflicting results. In order to clarify the effect of GSTP1 polymorphism on the BC susceptibility, we conducted an updated system review of published epidemiology studies to provide more precise evidence. We performed a systematic search of PubMed, EMBASE, and China National Knowledge Infrastructure (CNKI). 20 studies with 4,428 BC cases and 5,457 controls were identified. The combined analyses based on all studies showed that there was a significant difference in the genotype distribution in GSTP1(A313G) polymorphism between BC cases and controls not only in Asians (GG vs. AA + AG, OR = 1.59, 95 % CI = 1.01-2.51) but also in Caucasians (GG vs. AA + AG, OR = 1.51, 95 % CI = 1.11-2.06). Upon stratification for smoking status, we observed no statistically significant difference in genotype distribution of GSTP1 in ever-smokers. Combination of the high-risk genotypes (GSTM1 null + GSTT1 null + GSTP1 313 A/G or G/G) demonstrated further increase in the BC risk (OR = 6.64, 95 %CI = 3.63-12.16). This meta-analysis suggests that GSTP1 313 G/G polymorphism is a strong predisposing risk factor for BC.

Single nucleotide polymorphisms of 8 inflammation-related genes and their associations with smoking-related cancers

Tobacco smoke and its metabolites are carcinogens that increase tissue oxidative stress and induce target tissue inflammation. We hypothesized that genetic variation of inflammatory pathway genes plays a role in tobacco-related carcinogenesis and is modified by tobacco smoking. We evaluated the association of 12 single nucleotide polymorphisms of 8 inflammation-related genes with tobacco-related cancers (lung, oropharynx, larynx, esophagus, stomach, liver, bladder, and kidney) using 3 case-control studies from: Los Angeles (population-based; 611 lung and 553 upper aero-digestive tract cancer cases and 1,040 controls), Taixing, China (population-based; 218 esophagus, 206 stomach, 204 liver cancer cases, and 415 controls), and Memorial Sloan-Kettering Cancer Center (hospital-based; 227 bladder cancer cases and 211 controls). After adjusting for age, education, ethnicity, gender, and tobacco smoking, IL10 rs1800871 was inversely associated with oropharyngeal cancer (CT+TT vs. CC adjusted odds ratio [aOR]: 0.69, 95% confidence interval [CI]: 0.50-0.95), and was positively associated with lung cancer among never smokers (TT vs. CT+CC aOR: 2.5, 95% CI: 1.3-5.1) and inversely with oropharyngeal cancer among ever smokers (CT+TT vs. CC aOR: 0.63, 95% CI: 0.41-0.95). Among all pooled never smokers (588 cases and 816 controls), TNF rs1799964 was inversely associated with smoking-related cancer (CC vs. CT+TT aOR: 0.36, 95% CI: 0.17-0.77). Bayesian correction for multiple comparisons suggests that chance is unlikely to explain our findings (although epigenetic mechanisms may be in effect), which support our hypotheses, suggesting that IL10 rs1800871 is a susceptibility marker for oropharyngeal and lung cancers, and that TNF rs1799964 is associated with smoking-related cancers among never smokers.

Associations between NBS1 polymorphisms, haplotypes and smoking-related cancers

Constituents of tobacco smoke can cause DNA double-strand breaks (DSBs), leading to tumorigenesis. The NBS1 gene product is a vital component in DSB detection and repair, thus genetic variations may influence cancer development. We examined the associations between NBS1 polymorphisms and haplotypes and newly incident smoking-related cancers in three case-control studies (Los Angeles: 611 lung and 601 upper aero-digestive tract (UADT) cancer cases and 1040 controls; Memorial Sloan-Kettering Cancer Center: 227 bladder cancer cases and 211 controls and Taixing, China: 218 esophagus, 206 stomach, 204 liver cancer cases and 415 controls). rs1061302 was associated with cancers of the lung [adjusted odds ratio (OR(adj)) = 1.6, 95% confidence interval (CI): 1.2, 2.4], larynx (OR(adj) = 0.56, 95% CI: 0.32, 0.97) and liver (OR(adj) = 1.7, 95% CI: 1.0, 2.9). Additionally, positive associations were found for rs709816 with bladder cancer (OR(adj) = 4.2, 95% CI: 1.4, 12) and rs1063054 with lung cancer (OR(adj) = 1.6, 95% CI: 1.0, 2.3). Some associations in lung and stomach cancers varied with smoking status. CAC haplotype was positively associated with smoking-related cancers: lung (OR(adj) = 1.7, 95% CI: 1.1, 2.9) and UADT (OR(adj) = 2.0, 95% CI: 1.1, 3.7), specifically, oropharynx (OR(adj) = 2.1, 95% CI: 1.0, 4.2) and larynx (OR(adj) = 4.8, 95% CI: 1.7, 14). Bayesian false-discovery probabilities were calculated to assess Type I error. It appears that NBS1 polymorphisms and haplotypes may be associated with smoking-related cancers and that these associations may differ by smoking status. Our findings also suggest that single-nucleotide polymorphisms located in the binding region of the MRE-RAD50-NBS1 complex or microRNA targeted pathways may influence tumor development. These hypotheses should be further examined in functional studies.

Glutathione S-transferases: an overview in cancer research

IMPORTANCE OF THE FIELD

The Glutathione S-transferases (GSTs) have advanced beyond the classic view of their role in metabolism and are encouraging scientists to assess new approaches to cancer risk characterization and chemotherapy resistance and are opening up exciting possibilities in drug discovery.

AREAS COVERED IN THIS REVIEW

In this review, the most recent knowledge about the impact of GST genetic polymorphisms in human's cancer susceptibility, ethnic differences in the effects of risk factors and the rise of the GSTs as important targets for drug development are presented. In this context, the ethnic distribution of GST alleles in different populations, which is an important concept that is being incorporated in epidemiologic studies of cancer risk and environmental exposure, was also evaluated. We present up-to-date information about the new generation of GST-activated cytotoxic prodrugs based on GST overexpression in tumor-acquired drug resistance and the newest results of clinical trials.

WHAT THE READER WILL GAIN

A critical approach of the major advances in research of GST, underlining the new advances of GST genes polymorphisms in cancer susceptibility and target for therapeutic intervention.

TAKE HOME MESSAGE

Although polygenic factors are involved in increased risk of cancer, the interindividual GST variability plays a central role in reduce cells exposure to carcinogens.

Interaction between glutathione-S-transferase polymorphisms, smoking habit, and HPV infection in cervical cancer risk

PURPOSE

Human papillomavirus (HPV) infection is considered the major cause of cervical cancer (CC), but a number of infected women do not develop invasive lesions, suggesting the role of genetic susceptibility and environmental co-factors for cancer outbreak. The aim of this study was to investigate whether some GST polymorphisms could influence the risk to develop CC, either by themselves or in combination with smoking habit, in a cohort of high-risk HPV (HR-HPV) infected Italian women.

METHODS

The study population comprises 192 Italian women including 81 HR-HPV infected women bearing cervical lesions and 111 healthy controls. The cases include: 26 low-grade squamous intraepithelial lesions (LSILs), 30 high-grade-SIL, and 25 CCs, while controls were all negative for HPV. DNA was extracted from peripheral blood samples or cytobrush and individuals were genotyped for GSTM1, GSTT1, and GSTP1 polymorphisms using PCR and PCR/RFLP techniques.

RESULTS

On studying the association of GSTs gene polymorphisms with cervical cancer lesions, the combination of GSTM1 null, GSTT1 null and GSTP1 AA genotypes, independently on smoking habit, seems to be related to a 5.7-fold increased risk of developing CLs with a considerable statistical significance (P = 0.0091).

CONCLUSIONS

We suggest that the investigation of multiple gene polymorphisms, versus single genes, could contribute to a better understanding of the effect of susceptibility genes on cancer risk.

Genetic variation in the prostate stem cell antigen gene PSCA confers susceptibility to urinary bladder cancer

We conducted a genome-wide association study on 969 bladder cancer cases and 957 controls from Texas. For fast-track validation, we evaluated 60 SNPs in three additional US populations and validated the top SNP in nine European populations. A missense variant (rs2294008) in the PSCA gene showed consistent association with bladder cancer in US and European populations. Combining all subjects (6,667 cases, 39,590 controls), the overall P-value was 2.14 x 10(-10) and the allelic odds ratio was 1.15 (95% confidence interval 1.10-1.20). rs2294008 alters the start codon and is predicted to cause truncation of nine amino acids from the N-terminal signal sequence of the primary PSCA translation product. In vitro reporter gene assay showed that the variant allele significantly reduced promoter activity. Resequencing of the PSCA genomic region showed that rs2294008 is the only common missense SNP in PSCA. Our data identify rs2294008 as a new bladder cancer susceptibility locus.

Polymorphisms in DNA repair genes, smoking, and bladder cancer risk: findings from the international consortium of bladder cancer

Tobacco smoking is the most important and well-established bladder cancer risk factor and a rich source of chemical carcinogens and reactive oxygen species that can induce damage to DNA in urothelial cells. Therefore, common variation in DNA repair genes might modify bladder cancer risk. In this study, we present results from meta-analyses and pooled analyses conducted as part of the International Consortium of Bladder Cancer. We included data on 10 single nucleotide polymorphisms corresponding to seven DNA repair genes from 13 studies. Pooled analyses and meta-analyses included 5,282 cases and 5,954 controls of non-Latino white origin. We found evidence for weak but consistent associations with ERCC2 D312N [rs1799793; per-allele odds ratio (OR), 1.10; 95% confidence interval (95% CI), 1.01-1.19; P = 0.021], NBN E185Q (rs1805794; per-allele OR, 1.09; 95% CI, 1.01-1.18; P = 0.028), and XPC A499V (rs2228000; per-allele OR, 1.10; 95% CI, 1.00-1.21; P = 0.044). The association with NBN E185Q was limited to ever smokers (interaction P = 0.002) and was strongest for the highest levels of smoking dose and smoking duration. Overall, our study provides the strongest evidence to date for a role of common variants in DNA repair genes in bladder carcinogenesis.

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.

Associations between variants of the 8q24 chromosome and nine smoking-related cancer sites

Recent genome-wide association studies identified key single nucleotide polymorphisms (SNPs) in the 8q24 region to be associated with prostate cancer. 8q24 SNPs have also been associated with colorectal cancer, suggesting that this region may not be specifically associated to just prostate cancer. To date, the association between these polymorphisms and tobacco smoking-related cancer sites remains unknown. Using epidemiologic data and biological samples previously collected in three case-control studies from U.S. and Chinese populations, we selected and genotyped one SNP from each of the three previously determined "regions" within the 8q24 loci, rs1447295 (region 1), rs16901979 (region 2), and rs6983267 (region 3), and examined their association with cancers of the lung, oropharynx, nasopharynx, larynx, esophagus, stomach, liver, bladder, and kidney. We observed noteworthy associations between rs6983267 and upper aerodigestive tract cancers [adjusted odds ratio (ORadj), 1.69; 95% confidence interval (95% CI), 1.28-2.24], particularly in oropharynx (ORadj, 1.80; 95% CI, 1.30-2.49) and larynx (ORadj, 2.04; 95% CI, 1.12-3.72). We also observed a suggestive association between rs6983267 and liver cancer (ORadj, 1.51; 95% CI, 0.99-2.31). When we stratified our analysis by smoking status, rs6983267 was positively associated with lung cancer among ever-smokers (ORadj, 1.45; 95% CI, 1.05-2.00) and inversely associated with bladder cancer among ever-smokers (ORadj, 0.35; 95% CI, 0.14-0.83). Associations were observed between rs16901979 and upper aerodigestive tract cancer among never-smokers and between rs1447295 and liver cancer among ever-smokers. Our results suggest variants of the 8q24 chromosome may play an important role in smoking-related cancer development. Functional and large epidemiologic studies should be conducted to further investigate the association of 8q24 SNPs with smoking-related cancers.

Genetic polymorphisms of metabolic enzymes CYP1A1, CYP2D6, GSTM1 and GSTT1 and leukemia susceptibility

The genetic polymorphisms of biotransformation phase I enzymes, cytochrome P450 (CYP1A1 and CYP2D6), and phase II enzymes, glutathione S-transferase (GSTM1 and GSTT1), were analyzed in 204 healthy persons and 348 leukemia patients, who suffered from also acute lymphoblastic leukemia (ALL), acute nonlymphoblastic leukemia (ANLL) chronic myelogenous leukemia (CML), from the Han ethnic group in Changsha City of Hunan Province of China. Our results showed that the frequencies of polymorphisms of CYP1A1, CYP2D6 and GSTT1 among the groups including acute lymphoblastic leukemia, ANLL, chronic myelogenous leukemia and healthy control have no significant differences. The variation of GSTM1-null genotype alone correlated with the development of ANLL. The combined genotypes of GSTM1-null with GSTT1-null, or GSTM1-null with CYP1A1 heterozygous mutant, or GSTM1-null with CYP1A1 heterozygous mutant and CYP2D6 heterozygous mutant, or GSTM1-null with CYP1A1 heterozygous mutant, CYP2D6 heterozygous mutant and GSTT1-null were found in individuals with high risk of ANLL. All these findings suggest that GSTM1-null genotype alone or in coordination with the relevant genotypes of other metabolic enzymes might be susceptibility factors in the etiology of ANLL.

Association of CDH1 single nucleotide polymorphisms with susceptibility to esophageal squamous cell carcinomas and gastric cardia carcinomas

E-cadherin (CDH1) is a tumor suppressor involved in epithelial cell-cell interactions. Single nucleotide polymorphisms (SNP) in the CDH1 gene, -160C/A and -347G/GA in the 5'-promoter region and +54C/T in the 3'-untranslated region (UTR) have been shown to be associated with tumor development and progression via modifying transcriptional activity, mRNA stability or protein expression. To investigate the influence of CDH1 SNP on susceptibility to esophageal squamous cell carcinomas (ESCC) and gastric cardia adenocarcinomas (GCA), a case-control study was conducted among 333 ESCC patients, 239 GCA patients and 343 controls from a northern Chinese population. CDH1 polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis. The results showed that; (i) genotypes with the +54C allele (C/C or C/T) significantly increased the risk of developing both ESCC and GCA compared to the +54T/T genotype (age and gender adjusted odds ratio [OR] = 1.45 and 2.28, 95% confidence interval [CI] = 1.06-1.99 and 1.58-3.30, respectively), and this association was significant only among non-smokers (OR = 1.68 and 2.64, 95% CI = 1.01-2.80 and 1.43-4.87 for ESCC and GCA, respectively), and individuals without a family history of upper gastrointestinal cancer (OR = 2.63 and 2.97, 95% CI = 1.36-5.10 and 95% CI = 1.32-6.68 for ESCC and GCA, respectively); (ii) compared with the -347G/G genotype, the -347GA and GA/GA genotypes significantly increased the risk of developing GCA (OR = 1.45, 95 % CI = 1.03-2.04); (iii) there was a significant association of CDH1-160C/-347G/+54C and -160C/-347GA/+54C haplotypes with the development of GCA, compared with the -160C/-347G/+54T haplotype (OR = 1.80 and 2.21, 95% CI = 1.33-2.44 and 1.43-3.42, respectively); and (iv) the influence of CDH1 SNP on the depth of tumor invasion and lymphatic metastasis in ESCC and GCA patients was not observed in this study. The present study indicates that CDH1 polymorphisms might modify susceptibility to ESCC and/or GCA.

Hypermethylation of cell-free serum DNA indicates worse outcome in patients with bladder cancer

PURPOSE

CpG island hypermethylation is a frequent event in bladder carcinogenesis and progression. We investigated the diagnostic and prognostic value of hypermethylation in cell-free serum DNA of patients with bladder cancer.

MATERIALS AND METHODS

The study cohort consisted of 45 patients with bladder cancer undergoing cystectomy and 45 with histologically confirmed benign prostatic hyperplasia serving as controls. Hypermethylation at APC, DAPK, GSTP1, PTGS2, TIG1 and Reprimo was analyzed using real-time polymerase chain reaction following methylation sensitive restriction endonuclease treatment.

RESULTS

Hypermethylation at the APC and GSTP1 promoter was detected in 59% of cases, whereas TIG1 (32%), PTGS2 (24%) and DAPK (2%) were less frequently hypermethylated. In the benign prostatic hyperplasia group 3 patients also harbored methylated GSTP1 DNA, whereas none of the other gene sites was methylated. Hypermethylation at APC, GSTP1 or TIG1 distinguished patients with bladder cancer and controls most accurately with 80% sensitivity and 93% specificity. Hypermethylation significantly correlated with prognostic unfavorable clinicopathological parameters, including APC with pT stage, GSTP1, or GSTP1 or TIG1 with multifocal bladder cancer and APC, or APC or TIG1 with surgical margin positivity. Bladder cancer specific mortality was significantly increased in patients with APC hypermethylation.

CONCLUSIONS

The detection of hypermethylation in cell-free serum DNA provides valuable diagnostic and prognostic information that can still be improved by combining the results of 3 gene sites (APC, GSTP1 and TIG1). The presence of hypermethylated DNA in the serum of patients with bladder cancer is associated with a worse outcome. Our results suggest that measuring hypermethylation in the serum of patients with bladder cancer is a useful biomarker.

Short-Term Effects of Particulate Air Pollution on Male Smokers and Never-Smokers

BACKGROUND

Numerous studies have shown that ambient air pollution and smoking are both associated with increased mortality, but until now there has been little evidence as to whether the effects of these 2 factors combined are greater than the sum of their individual effects. We assessed whether smokers are subject to additional mortality risk from air pollution relative to never-smokers.

METHODS

This study included 10,833 Chinese men in Hong Kong who died at the age of 30 or above during the period 1 January to 31 December 1998. Relatives who registered for deceased persons were interviewed about the deceased's smoking history and other personal lifestyle factors about 10 years before death. Poisson regression for daily number of deaths was fitted to estimate excess risks per 10 microg/m increase in particulate matter with aerodynamic diameter <10 microm (PM10) in male smokers and never-smokers in stratified data, and additional excess risk for smokers relative to never-smokers in combined data.

RESULTS

In smokers there was a significant excess risk associated with PM10 for all natural causes and cardio-respiratory diseases for men age 30 years or older and men 65 or older. For all natural causes, greater excess risk associated with PM10 was observed for smokers relative to never-smokers: 1.9% (95% confidence interval = 0.3% to 3.6%) in men age 30 and older and 2.3% (0.4% to 4.3%) in those age 65 and older.

CONCLUSIONS

Ambient particulate air pollution is associated with greater excess mortality in male smokers compared with never-smokers.

Inducible Nitric Oxide Synthase Promoter Polymorphism, Cigarette Smoking, and Urothelial Carcinoma Risk

OBJECTIVES

Bladder carcinoma has a high inducible nitric oxide synthase (iNOS) content, and a highly polymorphic (CCTTT)n repeat in the iNOS promoter region has been identified. We explored whether this iNOS promoter polymorphism and cigarette smoking are associated with urothelial carcinoma (UC) risk.

METHODS

A total of 250 patients with pathologically confirmed UC and 250 unrelated noncancer controls were serially recruited at the Chia Yi Christian Hospital from August 2002 to May 2005. Multivariate logistic regression analysis was used to calculate the odds ratio and 95% confidence interval (CI).

RESULTS

A significantly increased UC risk was found in those who had smoked more than 30 years (odds ratio 2.4, 95% CI 1.5 to 4.2). The study subjects carrying the 12-repeat allele had a significantly increased UC risk (odds ratio 1.7, 95% CI 1.1 to 2.5). We also found the investigated polymorphism was related to clinical stage (P = 0.043). Of those who had ever smoked, those with the short/long (S/L) and long/long (L/L) genotypes (S, 9 to 11 repeats; L, 12 to 18 repeats) and the 12-repeat allele had a significantly increased UC risk of 3.5 (95% CI 1.7 to 7.3) and 4.5 (95% CI 2.2 to 8.9), respectively. Of the study subjects who had smoked longer than 30 years, those with S/L and L/L genotypes and the 12-repeat allele had significantly increased UC risks of 2.4 (95% CI 1.3 to 4.7) and 3.8 (95% CI 1.8 to 8.0), respectively.

CONCLUSIONS

These findings suggest that the polymorphic (CCTTT)n repeat in the iNOS promoter region might be involved in the development of UC, especially in those who have ever smoked.

Glutathione S-transferase gene polymorphisms and risk and survival of pancreatic cancer

BACKGROUND

Pancreatic cancer is a multifactorial disease with metastasis-prone and therapy-resistant nature. The authors hypothesized that genetic variants of glutathione S-transferase (GST) affect detoxification of carcinogens and anticancer agents in the human pancreas and, thus, the risk and survival of pancreatic cancer.

METHODS

Genotypes of GSTM1, GSTT1, and GSTP1 were determined in 352 patients with pancreatic ductal adenocarcinoma and in a control group of 315 healthy, non-Hispanic whites (frequency-matched by age and sex). Survival analysis was performed in a subset of 290 patients. Epidemiological and clinical information was obtained. A multiple unconditional logistic regression model, a Cox proportional hazards model, and log-rank tests were used for statistical analysis.

RESULTS

No significant main effects of any of 3 GST genes on the risk of pancreatic cancer were observed. Subgroup analysis showed that older individuals (aged >or=62 years) who carried the GSTP1*C ((105)Val-(114)Val) containing genotype tended to have a reduced risk compared with younger individuals who carried the non-*C genotype (for sex and pack-years of smoking, the adjusted odd ratio was 0.54; 95% confidence interval [95% CI], 0.29-1.02). In a survival analysis of 138 patients who received 5-flurorouracil, patients who carried the GSTP1*C containing genotype had a significantly longer survival than patients who carried the non-*C genotype (multivariate hazard ratio, 0.45; 95% CI, 0.22-0.94).

CONCLUSIONS

The GSTP1*C variant conferred a possible protective effect against pancreatic cancer in older individuals and a significant survival advantage in patients who received 5-florouracil. The current findings must be confirmed before further inferences can be made.