Genetic susceptibility to lung cancer with special emphasis on CYP1A1 and GSTM1: a study on host factors in relation to age at onset, gender and histological cancer types

Association between the combined effects of GSTM1 present/null and CYP1A1 MspI polymorphisms with lung cancer risk: an updated meta-analysis

Background: Many studies have been performed to explore the combined effects of glutathione-S-transferase M1 (GSTM1) present/null and cytochrome P4501A1 (CYP1A1) MspI polymorphisms with lung cancer (LC) risk, but the results are contradictory. Two previous meta-analyses have been reported on the issue in 2011 and 2014. However, several new articles since then have been published. In addition, their meta-analyses did not valuate the credibility of significantly positive results.

Objectives: We performed an updated meta-analysis to solve the controversy following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

Methods: False-positive report probability (FPRP), Bayesian false discovery probability (BFDP), and the Venice criteria were used to verify the credibility of meta-analyses.

Results: Twenty-three publications including 5734 LC cases and 7066 controls met the inclusion criteria in the present study. A significantly increased risk of LC was found in overall analysis, Asians and Indians. However, all positive results were considered as ‘less-credible’ when we used the Venice criteria, FPRP, and BFDP test to assess the credibility of the positive results.

Conclusion: These positive findings should be interpreted with caution and results indicate that significant associations may be less-credible, there are no significantly increased LC risk between the combined effects of GSTM1 present/null and CYP1A1 MspI polymorphisms.

Glutathione S-transferase θ1 polymorphism contributes to lung cancer susceptibility: A meta-analysis of 26 case-control studies

The GSTT1 gene encodes a key enzyme involved in the metabolism of xenobiotics and its polymorphisms have been associated with individual susceptibility to various malignancies. Numerous molecular epidemiological studies have been performed to investigate the association between GSTT1 gene polymorphisms and lung cancer susceptibility; however, the results of previous studies were inconsistent. Therefore, the aim of the present study was to conduct a meta-analysis in order to derive a more precise estimation of the association in the East Asian populations. The meta-analysis included 7,415 lung cancer cases and 6,084 controls from 26 published studies in East Asia, which were selected from the PubMed and China National Knowledge Infrastructure databases, up to March 20, 2014. Using crude odds ratios (ORs) with 95% confidence intervals (CIs), a statistically significant association was identified between the GSTT1 null genotype and lung cancer in the East Asian populations (OR=1.17; 95% CI, 1.09–1.25; P_{heterogeneity}=0.003). Furthermore, subgroup analyses revealed that the lung cancer risk in smokers carrying the GSTT1 null genotype was significantly increased compared with non-smokers (OR=1.71; 95% CI, 1.04–2.81; P_{heterogeneity}=0.002). Thus, the GSTT1 null genotype may increase the risk of lung cancer among the East Asian populations.

Combined effects of CYP1A1 MspI and GSTM1 genetic polymorphisms on risk of lung cancer: an updated meta-analysis

Genetic polymorphisms of cytochrome P450 1A1 (CYP1A1) and glutathione S-transferase M1 (GSTM1) genes might contribute to the variability in individual susceptibility to lung cancer, but the reported results from individual studies are not always consistent. We therefore conducted a meta-analysis to systematically estimate the associations between polymorphisms of these two genes and risk of lung cancer. Twenty-one studies with 8,926 subjects were finally enrolled into this study. Meta-analysis was performed by RevMan 5.2. Odds ratio (OR) and its 95 % confidence interval (CI) were calculated to evaluate the susceptibility to lung cancer. Compared with the wild-type homozygous genotype, significantly elevated risk of lung cancer were associated with variant CYP1A1 MspI (m1/m2 + m2/m2 vs. m1/m1: OR = 1.27, 95 % CI = 1.12-1.43, P < 0.001) and deletion of GSTM1 (null vs. present: OR = 1.26, 95 % CI = 1.13-1.40, P < 0.001). Both the two genetic polymorphisms were independently associated with the risk of lung cancer. The pooled OR of lung cancer for population with both CYP1A1 MspI and GSTM1 mutations (MspI m1/m2 or m2/m2 and GSTM1 null) was 1.62 (95 % CI 1.27-2.07, P < 0.001) when compared with those without any of the above mutations, which is higher than single genetic polymorphism. In the stratified analysis, significantly higher risks of lung cancer associated with above genetic polymorphisms were found only in Asian population. This meta-analysis suggests that the CYP1A1 MspI and GSTM1 polymorphisms correlate with increased lung cancer susceptibility independently, and that there is an interaction between the two genes. However, the associations vary in different ethnic populations.

CYP1A1 gene polymorphisms and smoking status as modifier factors for lung cancer risk

OBJECTIVE

Lung cancer remains the most prevalent malignancy worldwide. Susceptibility to lung cancer has been shown to be modulated by inheritance of polymorphic genes. Several metabolic enzymes are currently under investigation for their possible role in lung cancer susceptibility, including members of the cytochrome P450 (CYP) superfamily. The aim of this work was to identify the correlation between CYP1A1 m1 and m2 polymorphisms and lung cancer risk and figure its interactions with smoking as genetic modifiers in the etiology of lung cancer in the Egyptian population.

MATERIALS AND METHODS

One hundred and ten patients with lung cancer and one hundred and ten controls were enrolled in the study. CYP1A1 m1 and m2 polymorphisms were determined using polymerase chain reaction restriction fragment length polymorphism.

RESULTS

Subjects carrying TC and CC genotypes of CYP1A1 m1 and AG and GG genotypes of CYP1A1 m2 were significantly more likely to develop lung cancer especially squamous cell carcinoma. The proportion of lung cancer attributable to the interaction of smoking and CYP1A1 m1 and CYP1A1 m2 polymorphisms was 32% and 52% respectively.

CONCLUSION

Our results revealed that CYP1A1 m1 and m2 polymorphisms contribute to smoking related lung cancer risk in the Egyptian population.

CYP1A1 exon7 polymorphism is associated with lung cancer risk among the female population and among smokers: a meta-analysis

The genetic polymorphism of the CYP1A1 exon7 (rs1048943) gene is thought to have a significant effect on lung cancer risk, but the results are inconsistent. To assess this relationship more precisely, a meta-analysis was performed. Ultimately, 45 case-control studies, involving 19,689 subjects were included. A significantly increased lung cancer risk was associated with two exon7 genotype variants (for Val/Val vs Ile/Ile: odds ratio [OR] = 1.23, 95% confidence interval [CI] = 1.10-1.43; for (Ile/Val + Val/Val) vs Ile/Ile: OR = 1.16, 95% CI = 1.08-1.24) in the overall population. In the stratified analysis by ethnicity, gender, and smoking status, a significant association was found in Asians, Caucasians, and the female population, not the male population. Additionally, a significant association was found in the smoker population, not in the nonsmoker population. This meta-analysis suggests that the exon7 polymorphisms of CYP1A1 correlate with increased lung cancer susceptibility and there is an interaction between CYP1A1 exon7 polymorphisms and smoking, but these associations vary in different genders of the case and control populations.

CYP1A1 Ile462Val polymorphism contributes to lung cancer susceptibility among lung squamous carcinoma and smokers: a meta-analysis

Many studies have examined the association between the CYP1A1 Ile462Val gene polymorphisms and lung cancer risk in various populations, but their results have been inconsistent. To assess this relationship more precisely, a meta-analysis was performed. Ultimately, 43 case-control studies, comprising 19,228 subjects were included. A significantly elevated lung cancer risk was associated with 2 Ile462Val genotype variants (for Val/Val vs Ile/Ile: OR = 1.22, 95% CI = 1.08-1.40; for (Ile/Val +Val/Val) vs Ile/Ile: OR = 1.15, 95% CI = 1.07-1.23) in overall population. In the stratified analysis, a significant association was found in Asians, Caucasians and lung SCC, not lung AC and lung SCLC. Additionally, a significant association was found in smoker population and not found in non-smoker populations. This meta-analysis suggests that the Ile462Val polymorphisms of CYP1A1 correlate with increased lung cancer susceptibility in Asian and Caucasian populations and there is an interaction with smoking status, but these associations vary in different histological types of lung caner.

Cigarette smoke and adverse health effects: An overview of research trends and future needs

A large volume of data has accumulated on the issues of tobacco and health worldwide. The relationship between tobacco use and health stems initially from clinical observations about lung cancer, the first disease definitively linked to tobacco use. Almost 35 years ago, the Office of the Surgeon General of the United States Health Service reviewed over 7000 research papers on the topic of smoking and health, and publicly recognized the role of smoking in various diseases, including lung cancer. Since then, numerous studies have been published that substantiate the strong association of tobacco use with a variety of adverse human health effects, most prominently with cancer and cardiovascular diseases. Cigarette smoking is regarded as a major risk factor in the development of lung cancer, which is the main cause of cancer deaths in men and women in the United States and the world. Major advances have been made by applying modern genetic technologies to examine the relationship between exposure to tobacco smoke and the development of diseases in human populations. The present review summarizes the major research areas of the past decade, important advances, future research needs and federal funding trends.

CYP1A1 MspI and exon7 gene polymorphisms and lung cancer risk: an updated meta-analysis and review

BACKGROUND

Many studies have examined the association between the CYP1A1 MspI and exon 7 gene polymorphisms and lung cancer risk in various populations, but their results have been inconsistent.

METHODS

To assess this relationship more precisely, a meta-analysis and review were performed. The PubMed, Embase, Web of Science, and CNKI database was searched for case-control studies published up to June 2010. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated.

RESULTS

Ultimately, 64 studies, comprising 18,397 subjects from 49 case-control studies of the MspI genotype and 18,518 patients from 40 case-control studies of the exon 7 genotype, were included. A significantly elevated lung cancer risk was associated with 2 MspI genotype variants (for type C vs. Type A: OR = 1.26, 95% CI = 1.12-1.42; for types B and C combined vs. Type A: OR = 1.20, 95% CI = 1.13-1.28) in overall population. In the stratified analysis, a significant association was found in Asians, Caucasians, lung SCC, lung AC and Male population, not in mixed population, lung SCLC and female population. However, inconsistent results were observed for CYP1A1 exon7 in our meta-analysis, two variants of the exon 7 polymorphism were associated with a significantly higher risk for lung cancer (for Val/Val vs. Ile/Ile: OR = 1.24, 95% CI = 1.09-1.42; for (Ile/Val +Val/Val) vs. Ile/Ile: OR = 1.15, 95% CI = 1.07-1.24) in overall population. In the stratified analysis, a significant assocation was found in Asians, Caucasians, lung SCC and Female population, not in mixed population, lung AD, lung SCLC and Male population. Additionally, a significant association was found in smoker population and not found in non-smoker populations for CYP1A1 MspI and exon7 gene.

CONCLUSIONS

This meta-analysis suggests that the MspI and exon 7 polymorphisms of CYP1A1 correlate with increased lung cancer susceptibility and there is an interaction between two genotypes of CYP1A1 polymorphism and smoking, but these associations vary in different ethnic populations, histological types of lung cancer and gender of case and control population.

[Gender-associated differences of lung cancer and mechanism]

肺癌是全球发病率、死亡率最高、治疗效果差的恶性肿瘤。肺癌在流行病学、病理类型、疗效和预后、甚至发病机制等多方面均表现出明显性别差异。对这些差异的深入剖析能更好地认识男女性别肺癌各自的特点，为肺癌防治采用不同的性别化措施提供新线索和思路；而对导致性别差异的具体机制进行深入研究，有助于阐明肺癌的发病机制。

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

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

CYP1A1, GSTM1 and GSTT1 polymorphisms and lung cancer: a pooled analysis of gene–gene interactions

Gene-environment interactions have been extensively studied in lung cancer. It is likely that several genetic polymorphisms cooperate in increasing the individual risk. Therefore, the study of gene-gene interactions might be important to identify high-susceptibility subgroups. GSEC is an initiative aimed at collecting available data sets on metabolic polymorphisms and the risks of cancer at several sites and performing pooled analyses of the original data. Authors of published papers have provided original data sets. The present paper refers to gene-gene interactions in lung cancer and considers three polymorphisms in three metabolic genes: CYP1A1, GSTM1 and GSTT1. The present analyses compare the gene gene interactions of the CYP1A1*2A, GSTM1 and GSTT1 polymorphisms from studies on lung cancer conducted in Europe and the USA between 1991 and 2000. Only Caucasians have been included. The data set includes 1466 cases and 1488 controls. The only clear-cut association was found with CYP1A1*2A. This association remained unchanged after stratification by polymorphisms in other genes (with an odds ratio [OR] of approximately 2.5), except when interaction with GSTM1 was considered. When the OR for CYP1A1*2A was stratified according to the GSTM1 genotype, the OR was increased only among the subjects who had the null (homozygous deletion) GSTM1 genotype (OR = 2.8, 95% CI = 0.9-8.4). The odds ratio for the interactive term (CYP1A1*2A by GSTM1) in logistic regression was 2.7 (95% CI = 0.5-15.3). An association between lung cancer and the homozygous CYP1A1*2A genotype is confirmed. An apparent and biologically plausible interaction is suggested between this genotype and GSTM1.

Molecular epidemiology to better predict lung cancer risk

Although it is clear that smoking causes lung cancer, it is not known why some smokers develop the disease while others do not. Little is also known regarding risk factors for lung cancer among never-smokers, particularly women, or why women with lung cancer are more likely to have a family history of cancer, to be diagnosed at a young age, or to have adenocarcinoma. The application of molecular epidemiology to the study of lung cancer risk might facilitate elucidation of these questions. In this review, the molecular epidemiology of lung cancer is discussed, with an emphasis on studies of genetic variability in metabolic pathways as a means for determining susceptibility. Work that has assessed intermediate markers of risk, such as DNA adducts, is also presented, as are studies of tumor tissue alterations, such as mutations and DNA methylation, in relation to risk of lung cancer. Finally, approaches to evaluating factors that might explain the differing epidemiology of lung cancer between men and women are also presented. It is likely that, by incorporating biomarkers of susceptibility, exposure, and effect, molecular epidemiologic approaches might better define factors that explain some of the variability in lung cancer risk.

Green tea consumption is associated with decreased DNA damage among GSTM1-positive smokers regardless of their hOGG1 genotype

The levels of tobacco-related DNA adducts in human tissues reflect a dynamic process that is dependent on the intensity and time of exposure to tobacco smoke, the metabolic balance between activation of detoxification mechanisms, and the removal of adducts by DNA repair and/or cell turnover. Urinary 8-hydroxydeoxyguanosine (8-OHdG) is probably 1 of the most abundant DNA lesions formed during oxidative stress and is proposed as a sensitive biomarker of the overall oxidative DNA damage and repair. We performed this study to determine whether there were differences in increased oxidative stress susceptibility to smoking within the combined GSTM1 and hOGG1 genotypes and the impact of green tea drinking on this. We completed a Phase II randomized, controlled, 3-arm tea intervention trial to study the effect of high consumption of decaffeinated green or black tea or water on urinary 8-OHdG among heavy smokers and to evaluate the roles of GSTM1 and hOGG1 genotypes as effect modifiers. Assessment of urinary 8-OHdG after adjustment for baseline measurements and other potential confounders revealed a significant effect of green tea consumption (P = 0.001). The change from baseline was significant in all GSTM1-positive smokers regardless of their hOGG1 genotype. Our data show that consumption of 4 cups (960 mL) of tea/d is a feasible and safe approach and was associated with a significant decrease in urinary 8-OHdG among green tea consumers. Our finding also suggests that green tea intervention might be effective in decreasing DNA damage in the subgroup of smokers who are GSTM1 positive regardless of their hOGG1 genotype.

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

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

Miniaturization of primary porcine urinary bladder epithelial cell cultures and application for gene expression studies after exposure to benzo[a]pyrene

Benzo[a]pyrene (BaP) is an environmental pollutant used as a key marker substance for polycyclic aromatic hydrocarbons (PAHs). PAHs are believed to play a prominent role in the development of bladder cancer. A test system based on primary porcine urinary bladder epithelial cells (PUBEC) has been utilized as an in vitro model for urinary bladder epithelium. Recently in PUBEC cultures derived from pools of several bladders potent induction of CYP1A1 was detected after BaP treatment. Results from a modified approach using miniaturized PUBEC cultures for the analysis of individual bladder specimens with regard to cell growth and to BaP-mediated induction of CYP1A1 mRNA expression are presented herein. Two types of responses, low and high CYP1A1 induction among individual bladder specimens from eight donor animals, were detected. All of these tissue samples expressed the wild-type genotype of CYP1A1.

Biomarkers of air pollution exposure--a study of policemen in Prague

The effect of exposure to organic compounds adsorbed onto respirable air particles (<2.5microm) on DNA adducts in lymphocytes was studied in a group of non-smoking policemen (N=109, aged 35+/-0.9 years) working in the downtown area of Prague and spending >8h daily outdoors. Personal exposure to carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) adsorbed on respirable particles was monitored in each subject for 48h before biological sampling. DNA adducts were analyzed by a (32)P-postlabelling assay, and total DNA adduct levels and B[a]P-like spots were determined. Further biomarkers included cotinine levels in urine to control for exposure to tobacco smoke, plasma levels of vitamins A, E and C and polymorphisms of metabolic genotypes (GSTM1, GSTP1, GSTT1, CYP 1A1-Msp I and Ile/Val, MTHFR, MS), DNA repair genotypes (XRCC1, hOGG1 and XPD exons 6 and 23) and the p53 gene (p53 Msp I and BstU I). All the biomarkers of exposure and effect were analyzed repeatedly during a period of one year at 2-3 month intervals (January, March, June, September 2004) to cover periods with high (winter) and low (summer) levels of air pollution. The highest personal exposure to c-PAHs was found in January (8.1+/-8.8ng/m(3)), while the other three sampling periods exhibited 3-4-fold lower c-PAH exposure. The total DNA adducts were only slightly elevated in January (2.08+/-1.60) compared to March (1.66+/-0.65), June (1.96+/-1.73) and September (1.77+/-1.77). B[a]P-like DNA adducts, however, were significantly higher in January than in the March and June sampling periods (0.26+/-0.14 vs. 0.19+/-0.12 and 0.22+/-0.13, respectively; p<0.0001 and p=0.017) indicating that c-PAH exposure probably plays a crucial role in DNA adduct formation in lymphocytes. No effect of individual metabololic or DNA repair genotypes on DNA adduct levels was observed. However, the combination of two genotypes encoding enzymes metabolizing c-PAHs - CYP 1A1 and GSTM1 - was associated with the levels of total and B[a]P-like DNA adducts under conditions of increased exposure to c-PAHs. Our study suggests that DNA adducts in the lymphocytes of subjects exposed to increased c-PAH levels are an appropriate biomarker of a biologically effective dose, directly indicating whether or not the extent of exposure to these compounds is related to an increased mutagenic and carcinogenic risk.

Polymorphism of selected enzymes involved in detoxification and biotransformation in relation to lung cancer

Available data indicate that there are significant differences in individual susceptibility to lung cancer within the human population. It is believed to be underlie by inherited genetic predispositions related to the genetic polymorphism of several enzymes involved in the detoxification and xenobiotic metabolism. In this review, we collect and discuss the evidence reported up to date on the association between lung cancer and genetic polymorphism of cytochromes P450, N-acetyltransferase, glutathione S-transferases, microsomal epoxide hydrolase, NAD(P)H:quinone oxidoreductase, myeloperoxidase and glutathione peroxidase. All these genes might appear to be candidates for lung cancer susceptibility genes, nevertheless, the present state of the art still offers only a limited explanation of the link between such polymorphisms and increased risk of lung cancer.

Cigarette smoke condensate induces cytochromes P450 and aldo-keto reductases in oral cancer cells

Our objective is to identify molecular factors which contribute to the increased risk of smokers for oral squamous cell carcinoma (OSCC). In the present study, we investigated the effects of cigarette smoke condensate (CSC) on gene expression profiles in different human oral cell phenotypes: normal epidermal keratinocytes (NHEK), oral dysplasia cell lines (Leuk1 and Leuk2), and a primary oral carcinoma cell line (101A). We determined differential gene expression patterns in CSC-exposed versus non-exposed cells using high-density microarray RNA expression profiling and validation by quantitative real-time RT-PCR. A set of 35 genes was specifically up- or down-regulated following CSC treatment (25microg/ml for 24h) by at least 2-fold in any one cell type. Notably, five genes of the cytochrome P450 (CYP1A1, CYP1B1) and aldo-keto reductase (AKR1C1, AKR1C3, AKR1B10) families were highly increased in expression, some of them 15- to 30-fold. The timing and extent of induction for these genes differed among the four cell phenotypes. A potential biological interaction network for the CSC response in oral cells was derived from these data, proposing novel putative response pathways. These CSC-responsive genes presumably participate in the prevention or repair of carcinogen-induced DNA damage in tobacco-related oral carcinogenesis, and may potentially be exploited for determining the severity of exposure and for correcting mutagenic damage in exposed tissues of the oral cavity.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Relationship between genotype and enzyme activity of glutathione S-transferases M1 and P1 in Chinese

Glutathione S-transferases (GSTs) are the major detoxifying Phase II enzyme for eliminating electrophilic compounds. Mutations in GSTM1, GSTP1 and GSTT1 in Caucasian and GSTA1 in Chinese have been found to reduce enzyme activity. However, data on the impact of common genetic polymorphisms of GSTM1 and GSTP1 on enzyme activity in Chinese is lacking. This study aimed to investigate the effect of common GSTP1 and GSTM1 polymorphisms on erythrocyte GST activity in healthy Chinese (n = 196). GSTM1 null mutation (GSTM1*0) was analyzed by a PCR-Multiplex procedure, whereas GSTP1 313A-->G polymorphism (resulting in Ile105Val at codon 105) was analyzed by PCR-restriction fragment length polymorphism (RFLP) analysis. Erythrocyte GST activity was measured using 1-chloro-2,4-dinitro-bezene (CDNB) as the model substrate. The frequency of GSTM1 null genotype was 54.3% and the frequency of GSTP1-Ile/Ile, -Ile/Val, and -Val/Val genotype was 60.7%, 35.2% and 4.1%, respectively, with a frequency of 21.7% for the 105 valine allele. Age, gender and smoking did not significantly affect the erythrocyte GST activities. The mean erythrocyte GST enzyme activity for GSTP1*-Ile/Val genotype group (3.53 +/- 0.63U/gHb) was significantly lower than that for subjects with GSTP1-Ile/Ile genotype (4.25 +/- 1.07U/gHb, P = 0.004), while subjects with the GSTP1-Val/Val genotype had the lowest enzyme activity (2.44 +/- 0.67U/gHb). In addition, the GST activity in carriers of GSTM1*0/GSTP1-Ile/Ile was significantly higher than that of subjects inherited GSTM1*0/GSTP1-Ile/Val or GSTM1*0/GSTP1-Val/Val. However, there is no association between GSTM1 null mutation and reduced enzyme activity. GSTP1 codon 105 mutation led to reduced erythrocyte GST activity in Chinese. A combined GSTP1 and GSTM1 null mutations also resulted in significantly reduced GST activity. Further studies are needed to explore the clinical implications of GSTM1 and GSTP1 polymorphisms.

Five glutathione s-transferase gene variants in 23,452 cases of lung cancer and 30,397 controls: meta-analysis of 130 studies

BACKGROUND

Glutathione S-transferases (GSTs) are known to abolish or reduce the activities of intracellular enzymes that help detoxify environmental carcinogens, such as those found in tobacco smoke. It has been suggested that polymorphisms in the GST genes are risk factors for lung cancer, but a large number of studies have reported apparently conflicting results.

METHODS AND FINDINGS

Literature-based meta-analysis was supplemented by tabular data from investigators of all relevant studies of five GST polymorphisms (GSTM1 null, GSTT1 null, I105V, and A114V polymorphisms in the GSTP1 genes, and GSTM3 intron 6 polymorphism) available before August, 2005, with investigation of potential sources of heterogeneity. Included in the present meta-analysis were 130 studies, involving a total of 23,452 lung cancer cases and 30,397 controls. In a combined analysis, the relative risks for lung cancer of the GSTM1 null and GSTT1 null polymorphisms were 1.18 (95% confidence interval [CI]: 1.14-1.23) and 1.09 (95% CI: 1.02-1.16), respectively, but in the larger studies they were only 1.04 (95% CI: 0.95-1.14) and 0.99 (95% CI: 0.86-1.11), respectively. In addition to size of study, ethnic background was a significant source of heterogeneity among studies of the GSTM1 null genotype, with possibly weaker associations in studies of individuals of European continental ancestry. Combined analyses of studies of the 105V, 114V, and GSTM3*B variants showed no significant overall associations with lung cancer, yielding per-allele relative risks of 1.04 (95% CI: 0.99-1.09), 1.15 (95% CI: 0.95-1.39), and 1.05 (95% CI: 0.89-1.23), respectively.

CONCLUSIONS

The risk of lung cancer is not strongly associated with the I105V and A114V polymorphisms in the GSTP1 gene or with GSTM3 intron 6 polymorphism. Given the non-significant associations in the larger studies, the relevance of the weakly positive overall associations with the GSTM1 null and the GSTT1 null polymorphisms is uncertain. As lung cancer has important environmental causes, understanding any genetic contribution to it in general populations will require the conduct of particularly large and comprehensive studies.

Infection of human papillomavirus type 18 and p53 codon 72 polymorphism in lung cancer patients from India

STUDY OBJECTIVES

Infection with specific high-risk HPV types 16 and 18 and polymorphism of p53 codon 72 has been strongly associated with the genesis of various neoplasms in humans, but such study in lung cancer is limited and the results are controversial. In India, the role of these two factors has been strongly implicated in cervical and other cancers, but the occurrence of HPV or p53 codon 72 polymorphism has not been examined in lung cancer, which is the most common cause of cancer-related death in India.

DESIGN AND PATIENTS

A total of 40 tumor biopsy specimens from advanced lung cancer patients and blood samples from 40 matching control subjects were obtained for the analysis of high-risk HPV types 16 and 18 infection and p53 codon 72 polymorphism by polymerase chain reaction.

RESULTS

Only HPV type 18 was detected in 5% (2 of 40 lung cancer patients), but no other HPV could be detected. A significantly increased frequency of Arg/Arg homozygotes was observed in patients with advanced lung cancer when compared to that of control subjects (p = 0.004; odds ratio, 5.13; 95% confidence interval, 1.59 to 17.26). However, no significant correlation could be made between p53 polymorphism and different clinical stages, except for advanced stage IV patients, who showed a higher proportion of Arg/Pro heterozygous genotype.

CONCLUSIONS

HPV detected in a small proportion of lung cancer patients in India demonstrated an exclusive prevalence of HPV type 18, and there was a significantly higher frequency of p53 Arg/Arg genotype when compared to that of control subjects. Observation of a shorter duration of symptoms (< or = 4 months) in as many as 78% (seven of nine stage IV patients) with Arg/Pro genotype may be an indication that lung cancer patients with the heterozygous p53 genotype are more susceptible to early progression.

Metabolic gene polymorphisms and lung cancer risk in non-smokers. An update of the GSEC study

BACKGROUND

Since genetic factors may play an important role in lung cancer development at low dose carcinogen exposure, non-smokers are a good model to study genetic susceptibility and its interaction with environmental factors.

MATERIALS AND METHODS

We evaluated the role of the metabolic gene polymorphisms CYP1A1MspI, CYP1A1Ile462Val, GSTM1, and GSTT1 in non-smoker lung cancer patients from the International Collaborative Study on Genetic Susceptibility to Environmental Carcinogens (GSEC). Non-smokers (defined as subjects who never smoked on a regular basis) were selected from the GSEC database. We pooled the raw data from 21 case-control studies for a total of 2764 Caucasians (555 cases and 2209 controls) and 383 Asians (113 cases and 270 controls). Tests of heterogeneity and of inclusion bias were performed.

RESULTS

A significant association between lung cancer and CYP1A1Ile462Val polymorphism was observed in Caucasians (adjusted OR=2.04, 95% CI 1.17-3.54). GSTT1 deletion seems to be a risk factor for lung cancer in Caucasian non smokers only when the analysis was restricted to studies including healthy controls (adjusted OR=1.66, 95% CI 1.12-2.46). A protective effect on lung cancer was observed with the combination of CYP1A1 wild type, GSTM1 null, and GSTT1 non-null genotypes. None of the analysed polymorphisms were associated with lung cancer in Asian non-smokers.

DISCUSSION

Our analysis confirms previous findings that CYP1A1Ile462Val polymorphism may play a role in lung carcinogenesis in Caucasian non-smokers.

Polymorphisms of the GSTM1, GSTP1, MPO, XRCC1, and NQO1 genes in Chinese patients with non-small cell lung cancers: relationship with aberrant promoter methylation of the CDKN2A and RARB genes

An association between functional polymorphisms of genes resulting in decreased detoxification of carcinogens or DNA repair and aberrant promoter methylation is an attractive hypothesis in lung carcinogenesis. The genotypes at polymorphic sites of the glutathione S-transferase (GST) M1 (null/wildtype) and P1 (nucleotide 2627 A/G), myeloperoxidase (MPO) (nucleotide -463 G/A), X-ray repair cross-complementing group 1 (XRCC1) (nucleotides 26304 C/T; 28152 G/A), and NADPH quinine oxidoreductase (NQO1) (nucleotide 609 C/T) genes in 75 Chinese patients with non-small cell lung cancer (NSCLC) were characterized with polymerase chain reaction-restriction fragment length polymorphism. Results were correlated with aberrant methylation of the CDKN2A (alias p16(INK4A)), retinoic acid receptor beta (RARB), methylguanine-DNA methyltransferase (MGMT), and death-associated-protein (DAP) kinase genes in the tumors. In comparison with an age-matched control, none of the polymorphisms were associated with increased lung cancer risks. In male patients, however, the MPO -463 GG homozygous state was associated with CDKN2A (alias p16(INK4A)) methylation (odds ratio OR=3.63, 95% confidence interval CI=1.26-10.51), and the XRCC1 26304 T allele in the heterozygous/homozygous state was associated with methylation of CDKN2A (OR=6.13, 95% CI=1.55-24.16) and RARB (OR=7.67, 95% CI=1.62-36.18). In female patients, the GSTP1 G allele in the heterozygous/homozygous state was associated with RARB methylation (OR=18.0, 95% CI=0.76-427.29). These results showed that functional deficiencies in metabolic pathways that protect cells from carcinogen induced DNA damage might be linked to aberrant promoter methylation of the CDKN2A and RARB genes during lung carcinogenesis.

Cytochrome P-450 1A1 gene polymorphisms and risk of breast cancer: a HuGE review

Cytochrome P-450 (CYP) 1A1 plays a key role in phase I metabolism of polycyclic aromatic hydrocarbons and in estrogen metabolism. It is expressed predominantly in extrahepatic tissues, including the breast. Four CYP1A1 gene polymorphisms (3801T --> C, Ile462Val, 3205T --> C, and Thr461Asp) have been studied in relation to breast cancer. The 3801C variant is more common than the Val variant. Both variants occur more frequently in Asians than in White populations. The 3205T --> C polymorphism has been observed in African Americans only. Little data are available on the geographic/ethnic distribution of the Thr461Asp polymorphism. The functional significance of the polymorphisms is unclear. In 17 studies, no consistent association between breast cancer and CYP1A1 genotype was found. Meta-analysis found no significant risk for the genotypes 1) 3801C/C (relative risk (RR) = 0.97, 95% confidence interval (CI): 0.52, 1.80) or 3801T/C (RR = 0.91, 95% CI: 0.70, 1.19) versus 3801T/T, 2) Val/Val (RR = 1.04, 95% CI: 0.63, 1.74) or Ile/Val (RR = 0.92, 95% CI: 0.76, 1.10) versus Ile/Ile, or 3) Asp/Asp (RR = 0.95, 95% CI: 0.20, 4.49) or Thr/Asp (RR = 1.12, 95% CI: 0.87, 1.43) versus Thr/Thr. Future studies should explore possible interactions between CYP1A1 and sources of polycyclic aromatic hydrocarbons, markers of estrogen exposure, other lifestyle factors influencing hormonal levels, and other genes involved in polycyclic aromatic hydrocarbon metabolism or hormonal biosynthesis.

CYP1A1 and GSTM1 polymorphisms in relation to lung cancer risk in Chinese women

We examined CYP1A1 (I462V) and GSTM1 null polymorphisms in 200 female cases and 144 female controls selected from a population-based case-control study of lung cancer conducted in northeast China, where the rates of lung cancer among Chinese women are especially high. The CYP1A1 codon 462 point mutation in exon 7 (I462V) causes an Ile-Val substitution near the heme binding site. This mutation correlates with inducibility of aryl hydrocarbon hydrolase (AHH) activity, which activates polycyclic aromatic hydrocarbons (PAHs) in tobacco smoke and in indoor air pollution from coal-burning stoves, a risk factor for lung cancer in this study population. We found that the CYP1A1 I462V genotype (combined ile/val and val/val) was significantly associated with lung cancer risk. The odds ratio (OR) was 2.5 (95% confidence interval [CI], 1.55-4.03) after adjustment for significant risk factors such as age, ever smoking status, family history of cancer, and eye irritation when cooking. The association was more pronounced among non-smokers (OR=3.67; 95% CI, 1.85-7.28) than among smokers (OR=1.74, 95% CI, 0.85-3.54). In contrast, we did not find a significant association with the GSTM1 null genotype. In summary, our case-control study of lung cancer among women in northeast China revealed an elevated risk associated with the CYP1A1 I462V genotype, but no interaction with smoking or indoor air pollution was found.

Genetic susceptibility to tobacco-related cancer

Although cigarette smoking is the dominant risk factor for several epithelial cancers, only a small fraction of individuals with tobacco exposure develop cancer. The underlying hypothesis is that genetic factors may render certain smokers more susceptible to cancer than others. Genetic alterations in critical regulatory pathways may predispose cells to carcinogenesis. These pathways include regulation of xenobiotic metabolism; control of genomic stability, including DNA repair mechanisms, cell-cycle checkpoints, apoptosis and telomere length; and control of microenvironmental factors, such as matrix metalloproteinases, inflammation and growth factors. In addition, epigenetic events, such as promoter hypermethylation and loss of imprinting, are also involved in carcinogenesis. In this review, we will summarize recent advances in genetic susceptibility to tobacco-related cancer. Emphasizing on risk assessment, we will describe how genetic variations in the above-mentioned genetic pathways modify the tobacco-related cancer risk. In addition, we will discuss how genetic variations may assist in predicting clinical outcome, such as the natural history of cancer and treatment response. The measurements of genetic susceptibility by both genotypic and phenotypic assays are covered in the text. Finally, we present a number of current concerns that need to be addressed as the exciting field of molecular cancer epidemiology advances rapidly.

Influence of CYP1A1, GSTM1, GSTT1, and NQO1 Genotypes and Cumulative Smoking Dose on Lung Cancer Risk in a Swedish Population

The major identified risk factor for lung cancer is tobacco smoking. We identified previously the possible modifying influence of CYP1A1 and GSTM1 polymorphisms on lung cancer risk in a Swedish population. The present study, extended by several study subjects and with analyses for polymorphisms in GSTT1 and NQO1, includes 524 lung cancer cases and 530 control subjects. No evidence for an influence of genetic polymorphisms in CYP1A1, GSTM1, GSTT1, and NQO1 on lung cancer risk overall was found. In smokers, there was, however, a suggestion that the variant CYP1A1 and NQO1 genotypes may confer an increased risk for squamous cell carcinoma. In ever smokers, the homozygously deleted GSTM1 (GSTM1*O/*O) genotype was significantly associated with increased risk of small cell carcinoma (adjusted odds ratio 2.72, 95% confidence interval 1.32-5.90). The risks noted for the variant CYP1A1 genotypes and the GSTM1*O/*O genotype seemed to be restricted to light smokers. The GSTT1*O/*O genotype also appeared to be a possible risk factor in light smokers, whereas, in heavy smokers, this genotype was associated with decreased risk for lung cancer overall (odds ratio 0.36, 95% confidence interval 0.13-0.99). Due to the multiple comparisons made, we cannot exclude the possibility that some of these associations may represent chance findings.

Effect of a 4-Month Tea Intervention on Oxidative DNA Damage among Heavy Smokers

Glutathione S-transferase (GST), a member of the phase II group of xenobiotic metabolizing enzymes, has been intensively studied at the levels of phenotype and genotype. The GST mu 1 (GSTM1) and GST theta 1 (GSTT1) genes have a null-allele variant in which the entire gene is absent. The null genotype for both enzymes has been associated with many different types of tumors. The aim of this study was to determine the possible differences in increased oxidative stress susceptibility to smoking within the GSTM1 and GSTT1 genotypes and the impact of high tea drinking on this. We designed a Phase II randomized, controlled, three-arm tea intervention trial to study the effect of high consumption (4 cups/day) of decaffeinated green or black tea, or water on oxidative DNA damage, as measured by urinary 8-hydroxydeoxyguanosine (8-OHdG), among heavy smokers over a 4-month period and to evaluate the roles of GSTM1 and GSTT1 genotypes as effect modifiers. A total of 133 heavy smokers (100 females and 33 males) completed the intervention. GSTM1 and GSTT1 genotype statuses were determined with a PCR-based approach. Multiple linear regression models were used to estimate the main effects and interaction effect of green and black tea consumption on creatinine-adjusted urinary 8-OHdG, with or without adjustment for potential confounders. Finally, we studied whether the effect of treatment varied by GSTM1 and GSTT1 status of the individual. Although there were no differences in urinary 8-OHdG between the groups at baseline, the between-group 8-OHdG levels at month 4 were statistically significant for GSTM1-positive smokers (P = 0.05) and GSTT1-positive smokers (P = 0.02). GSTM1-positive and GSTT1-positive smokers consuming green tea showed a decrease in urinary 8-OHdG levels after 4 months. Assessment of urinary 8-OHdG after adjustment for baseline measurements and other potential confounders revealed significant effect for green tea consumption (P = 0.001). The change from baseline was significant in both GSTM1-positive (t = -2.99; P = 0.006) and GSTT1-positive (P = 0.004) green tea groups, but not in the GSTM1-negative (P = 0.07) or GSTT1-negative (P = 0.909) green tea groups. Decaffeinated black tea consumption had no effect on urinary 8-OHdG levels among heavy smokers. Our data show that consumption of 4 cups of tea/day is a feasible and safe approach and is associated with a significant decrease in urinary 8-OHdG among green tea consumers after 4 months of consumption. This finding also suggests that green tea intervention may be effective in the subgroup of smokers who are GSTM1 and/or GSTT1 positive.

Occupational and environmental levels of mutagenic PAHs and respirable particulate matter associated with diesel exhaust in Santiago, Chile

This work studied the mutagenic potential and polycyclic aromatic hydrocarbon (PAH) levels onto PM10 collected in diesel revision plants, in an urban area as well as in a rural area in Santiago, Chile. The PM10 average levels in diesel emission plants during working hours (there is no occupational PM10 Chilean standard) were significantly higher than the atmospheric Chilean PM10 standard and highly mutagenic and with high PAHs levels. Additionally, we evaluated the contribution of CYP1A1 and GSTM1 polymorphisms on 1-OH-pyrene urinary levels. The diesel-exposed workers carrying the CYP1A1*2A allele showed significantly higher 1-OH-P levels than the subjects from the rural area with the same genotype. The higher levels of 1-OH-P were found in individuals carrying the combined CYP1A1*2A and GSTM1 null genotype. This kind of information might be relevant to establish prevention, protection, and mitigation actions to protect public health.

GST genetic polymorphisms and lung adenocarcinoma susceptibility in a Chinese population

Lung adenocarcinoma (AC) has been increasing over the last several decades in many countries, including China. Some of the glutathione S-transferases (GSTs) demonstrate polymorphisms which may play a role in lung AC susceptibility. Our previous study of a Chinese population found the GSTM1 null genotype to be associated with an increased risk of lung AC, and the combination of GSTM1 null genotype and CYP2E1 wild type conferred a significantly elevated risk. Here, we extended the study to investigate the potential role of GSTT1 and GSTP1 polymorphisms in likelihood of development of lung AC, either separately or in combination. This case-control study encompassed 112 cases with lung ACs and 119 age- and gender-matched cancer-free controls from Beijing. The frequencies for the GSTM1 null genotype were 61.6 and 50.4% among cases and controls, and for the GSTT1 null genotype 47.3 and 45.4%, respectively. The distribution of the GSTP1 Ile/Ile, Ile/Val and Val/Val genotypes was 59.8, 39.3 and 0.9% in cases, and 70.6, 28.6 and 0.8% in controls, respectively. No relationship between lung AC and the GSTT1 genotype was observed in the present study, either separately or in combination with the GSTM1 or GSTP1 genotypes. Although separate GSTM1 and GSTP1 polymorphisms were not statistically related to lung AC, the combination of GSTM1 null and GSTP1 Val was significantly associated with an elevated lung AC risk (OR=2.4, 95% CI 1.1-5.1).

Genetic polymorphisms and environmental risk of lung cancer: a review

Lung cancer results from man-made and natural environmental exposures acting in concert with both genetic and acquired characteristics. Chronic inhalation of cigarette smoke is a major risk factor, and environmental tobacco exposure can cause lung cancer in life-long neversmokers. Air pollution, indoor-radon exposure, occupational exposures, dietary, physical activity, and reproductive history have been identified as independent or contributing risk factors for lung cancer. Because only a small portion of smokers develops the disease, genetic susceptibility can contribute to the risk. Developments in molecular biology have led to the discovery of biological markers that increase predisposition to lung carcinogenesis. Therefore, the high-risk genotype of an individual can be determined easily. Because of the great number of carcinogen-activating and -detoxifying enzymes, the variation in their expression, the complexity of exposures to tobacco carcinogens, and the existence of multiple alleles at loci of those enzymes results in differential susceptibilities of individuals. As lung cancer is a multifactorial disease, an improved understanding of the interplay of environmental and genetic polymorphisms at multiple loci can help identify individuals who are at increased risk for lung cancer. Hopefully, in the future we will be able to screen for lung cancer susceptibility by using specific biomarkers.

CYP1A1 polymorphism and risk of gynecological malignancy in Japan

The incidence of endometrial cancer and ovarian cancer in Japan has been increasing in recent years. Results of epidemiologic studies suggest that the onset and multiplication of these cancers are associated with estrogen. Estrogens are metabolized by cytochrome P450 1A1 (CYP1A1) and converted into catecholestrogens, which are carcinogens. CYP1A1 has several polymorphisms, the major one being T6235C transition in the non-coding 3'-flanking region (MspI polymorphism), and another being A4889G transition in exon 7 (Ile/Val polymorphism). These polymorphisms can affect the metabolites of estrogens and contribute to the susceptibility to gynecological malignancy. In this study, to determine whether CYP1A1 polymorphism plays a role in the development of gynecological malignancy in the Japanese population, we assessed the association of CYP1A1 polymorphism in Japanese patients with gynecological malignancy in comparison to that in controls. The odds ratios (ORs) of Ile/Val polymorphism were 1.16 in ovarian cancer patients and 1.70 in endometrial cancer patients. The ORs of MspI polymorphism were 1.33 in ovarian cancer patients and 0.88 in endometrial cancer patients. No significant association was found between these CYP1A1 polymorphisms and gynecological malignancy. Although the frequency of CYP1A1 polymorphism in the Japanese population is higher than that in the Caucasian population, CYP1A1 polymorphism is not related to gynecological malignancies in Japanese population.

Positive correlation between single or combined genotypes of CYP1A1 and GSTM1 in relation to prostate cancer in Chilean people

BACKGROUND

The prostate cancer is a slowly progressing disease that begins decades prior to diagnosis. It has been suggested that there might be differences in susceptibility due to genetic polymorphisms in biotransformation enzyme genes. In the present work, associations between CYP1A1(Msp1), GSTM1(-/-) polymorphisms, and prostate cancer were analyzed in a case-control study.

METHODS

Genomic DNA was isolated from peripheral blood samples, collected on EDTA. PCR-RFLP was used to determine simultaneously Msp1 and GSTM1(-/-) polymorphisms.

RESULTS

In cancer patients, frequency of m2 variant allele (0.377) and GSTM1(-/-) (0.362) showed statistically significant increases compared to the control group (0.262 and 0.227, respectively). The estimate relative risks (OR) were higher for individuals carrying combined CYP1A1 and GSTM1 rare genotypes, in relation to individuals carrying CYP1A1 or GSTM1 alone. Multivariate logistic regression analysis including confounding factors (age, digital examination, and PSA antigen) showed even higher risk for individuals carrying m2m2 genotype (OR = 3.99; 95% CI, 1.27-12.54), GST(-/-) genotype (OR = 2.75; 95% CI, 1.31-5.79), and m2m2/GST(-) genotype (OR = 16.63; 95% CI, 1.67-165.48).

CONCLUSIONS

Taken together, these findings suggest that Chilean people carrying single or combined GSTM1 and CYP1A1 polymorphisms are more susceptible to prostate cancer.

Association of GSTM1, CYP1A1 and CYP2E1 genetic polymorphisms with susceptibility to lung adenocarcinoma: a case-control study in Chinese population

A case-control study of 164 lung adenocarcinoma (AC) patients with 181 age- and gender-matched healthy controls was conducted in order to assess any associations between glutathione-S-transferase M1 (GSTM1), cytochrome P4501A1 (CYP1A1) and cytochrome P4502E1 (CYP2E1) polymorphisms and susceptibility to lung AC in Chinese. The presence of CYP2E1 variant allele was significantly less frequent in cases than in controls, while the distribution of GSTM1 null genotype and variant CYP1A1 Msp1 allele did not vary between cases and controls. After adjustment for age, gender, smoking and all other genotypes, the CYP2E1 Rsa1 variant allele was significantly associated with decreased risk of lung AC [odds ratio 0.534 (95% confidence interval, 0.340-0.837)]. Furthermore, 3.0-fold increased risk was found in individuals with combined GSTM1 null genotype and CYP2E1 Rsa1 wild type versus those with combined GSTM1 non-null type and CYP2E1 variant allele. Our results suggest that CYP2E1 Rsa1 variant allele is associated with a decreased risk of lung AC, and combined GSTM1 null genotype and CYP2E1 Rsa1 wild type has a promoting effect on susceptibility to lung AC.

A mulher e o cancro do pulmão**Textos referentes à mesa-redonda com o mesmo título organizada pela Comissão de Trabalho de «Pneumologia Oncológica». Coimbra, 13 de Abril de 2002

The epidemiology of lung cancer has changed in the last years in several countries all over the world. In the 19th century, the lung cancer was rare but it incidence increase drastically during the 20th century, and the tendency is to continue in the 20th century. Actually the lung cancer's incidence and mortality are higher in the developed countries, especially in Europe and Unites States of America, with a increasing in the women incidence. These geographic differences and gender differences are related with smoking habits. Women begin to smoke earlier and have more difficulty to stop, because of problems related with obesity; they have more sensibility to the carcinogens and the risk of lung cancer is 1.5 times higher than the men with the same habits. Adenocarcinoma is the more frequent histological type in young people, in the total of the women and in non-smokers. Many factors since tobacco, home and professional pollution, nutritional, associated diseases even genetic and hormonal factors have been investigated to define its influence in development in women lung cancer. It specificity in women with lung cancer is the common problem for the medical people to treat this disease (pathology).The literature about this problem is not clear, and is necessary to advance with many studies in this area with the objective to clarify this important question.