CYP1A1, GSTM1, and GSTP1 genetic polymorphisms and urinary 1-hydroxypyrene excretion in non-occupationally exposed individuals.

The CYP1A1 and glutathione S-transferase enzymes (e.g., GSTM1 and GSTP1) are involved in the activation and conjugation of polycyclic aromatic hydrocarbons (PAHs), respectively, and are controlled by genes that are polymorphic. The CYP1A1*2 allelic variant has been associated with elevated urinary 1-hydroxypyrene (1-OHP), a proposed marker for internal dose of activated PAHs, in coke-oven workers. We investigated whether this association could be observed at low exposure levels, such as those experienced by the general population. We conducted a cross-sectional study among 188 individuals (106 Japanese, 60 Caucasians, and 22 Hawaiians) who were selected as controls in a population-based case-control study and provided lifestyle information, a 12-h urine specimen, and a blood sample. 1-OHP was analyzed by high-performance liquid chromatography after enzymatic hydrolysis. Lymphocyte DNA was used for PCR-based genotyping. Smokers excreted twice as much 1-OHP (geometric mean, 0.51 nmol/12 h) as nonsmokers (geometric mean, 0.27 nmol/12 h; P = 0.006). Overall and among nonsmokers, 1-OHP urinary levels did not differ by CYP1A1, GSTM1, or GSTP1 genotypes. However, after adjusting for age, ethnicity, and number of cigarettes per day, smokers with at least one CYP1A1*2 variant allele excreted 2.0-fold more 1-OHP than smokers with the wild-type genotype (P = 0.02). Similar results were obtained for the CYP1A1*3 variant allele. The present data add to the growing evidence suggesting that individuals with the (linked) CYP1A1*2 or *3 variant alleles have a greater capacity to activate PAHs from tobacco smoke and occupational exposure and, as a result, are at greater risk for PAH-related cancers, especially certain respiratory cancers.     

Effects of occupation, lifestyle and genetic polymorphisms of CYP1A1, CYP2E1, GSTM1 and GSTT1 on urinary 1-hydroxypyrene and 2-naphthol concentrations

This study was undertaken to determine the effects of occupation, lifestyle and the genetic polymorphisms of cytochrome P450 1A1 (CYP1A1), cytochrome P450 2E1 (CYP2E1) and glutathione S-transferases micro1 (GSTM1) and 1 (GSTT1) on the concentrations of urinary 1-hydroxypyrene (1-OHP) and 2-naphthol among Korean coke oven workers and university students. The study subjects included 90 coke oven workers and 128 university students. A questionnaire was used to obtain detailed data about the work area, smoking habits and food intake of subjects. Associations between urinary polycyclic aromatic hydrocarbon (PAH) concentrations and occupation, smoking status, total airborne PAH level and genetic polymorphisms were tested. Urinary 1-OHP and 2-naphthol concentrations were higher in coke oven workers than in students and correlated significantly with work area. Urinary 2-naphthol concentrations increased with an increase in the level of cigarette smoking in students. Total airborne PAH level correlated with urinary 1-OHP concentration in coke oven workers. Urinary 1-OHP and 2-naphthol concentrations were higher in coke oven workers with the c1/c2 or c2/c2 genotype of CYP2E1 than in those with the c1/c1 genotype. Urinary 2-naphthol concentrations were higher in GSTM1-null workers than in GSTM1-positive workers. In multiple regression analysis CYP2E1 was a significant factor determining urinary 1-OHP concentrations in coke oven workers. CYP2E1 and GSTM1 were significant determinants for urinary 2-naphthol concentrations in coke oven workers and GSTM1 and smoking were prognosticators among university students. Urinary 1-OHP is a better indicator of occupational exposure to PAH in coke oven workers than 2-naphthol, whereas urinary 2-naphthol may be more sensitive for non-occupational inhalation exposure to PAH. In occupationally exposed populations CYP2E1 and GSTM1 appear to play an important role in the metabolism of pyrene and naphthalene. In individuals not occupationally exposed to PAHs GSTM1 and smoking seem to influence the urinary concentration of 2-naphthol.     

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 polymorphisms of CYP1A1, GSTM1 and GSTT1 genes and lung cancer risk

Genetic polymorphisms of the genes encoding for the xenobiotic metabolizing enzymes result in individual variations in the efficiency of detoxification of environmental carcinogens, and have been extensively associated with variable risk for lung neoplasms in different ethnic and environmental backgrounds. In this study, using PCR-RFLP based assays, we investigated the distribution of genetic polymorphisms in CYP1A1, GSTM1 and GSTT1 genes in Greek lung cancer patients (N=122) and healthy controls (N=178). The frequency of CYP1A1 m1 homozygous genotype was 0.04 in patients and 0.02 in controls (detected in 4.10% of patients and in 1.69% of controls, respectively), that of GSTM1 null genotype was 0.52 in patients and 0.54 in controls, whereas those of GSTT1 null genotype was 0.17 and 0.11, in patients and controls, respectively. The GSTM1 null genotype was more frequent in adenocarcinoma, as well as in lung cancer patients with history of chronic obstructive pulmonary disease (COPD). The GSTT1 null genotype correlated with advanced age of the patients at the time of diagnosis. Three combinations of rare genotypes - in subjects carrying simultaneously deviations from the common genotype in more than one gene - were over-represented in lung cancer patients, compared to control population, and were furthermore significantly associated with history of heavy tobacco consumption in lung cancer patients. The results imply involvement of specific genotype combinations of CYP1A1, GSTM1 and GSTT1 alleles in the development of lung cancer in heavy smokers.     

GSTM1和CYP1A1基因多态性与宫颈癌发生及发展的相关性

目的:探讨谷胱苷肽硫转移酶M1（GSTM1）和CYP1A1 Exon7基因多态性与宫颈癌发生发展的关系。方法:选取2013年5月至2015年5月我院收治的宫颈癌患者184例为宫颈癌组,203例进行体检的健康人群为参照组。用限制性片段长度多态性-聚合酶链反应（RFLP-PCR）检测所有受试者GSTM1和CYP1A1 Exon7基因型;记录无进展生存期（PFS）,并随访观察生存和死亡情况。结果:GSTM1分为野生型（wt）和突变缺失型（null）,CYP1A1 Exon7野生型为Ⅱe/Ⅱe,突变型包括突变纯合型（Val/Val）、突变杂合型（Ⅱe/Val）。宫颈癌组携带GSTM1突变型基因型比例与参照组间比较,差异无统计学意义（P＞0.05）;宫颈癌组携带CYP1A1 Exon7突变型基因型比例显著高于参照组（P＜0.05）,且携带突变型基因型个体患宫颈癌的风险是携带野生型基因型个体的2.333倍。GSTM1、CYP1A1 Exon7基因型与宫颈癌患者年龄、病理分期、肿瘤分化程度、肿瘤直径及淋巴结转移均无关（P＞0.05）,与患者病理类型有关（P＜0.05）。GSTM1、CYP1A1 Exon7突变型宫颈癌患者PFS中位数与野生型患者比较,差异均无统计学意义（P＞0.05）。GSTM1、CYP1A1 Exon7突变型宫颈癌患者基因型与宫颈癌患者预后无关（P＞0.05）。结论:GSTM1及CYP1A1 Exon7基因多态性是宫颈癌发生发展的危险因素,尤其是CYP1A1 Exon7突变型,为预防宫颈癌提供依据。     

CYP1A1 and GSTM1 polymorphisms and lung cancer risk in Chinese populations: a meta-analysis

Genetic polymorphisms of cytochrome p450 (CYP1A1) and glutathione S-transferase M1 (GSTM1) genes are thought to have significant effects on the metabolism of environmental carcinogens and thus on cancer risk, but the reported results are not always consistent. In this meta-analysis, we assessed reported studies of associations between polymorphisms of these two genes and risk of lung cancer in Chinese populations. Through a systematic literature search for publications between 1989 and 2006, we summarized the data from 46 studies on polymorphisms of MspI and exon7-Val of CYP1A1 and GSTM1 and lung cancer risk in Chinese populations, and found that compared with the wild-type homozygous genotype (type A), lung cancer risk for the combined variant genotypes (types B and C) was 1.34-fold (95% confidence interval [CI]=1.08-1.67) (Z=2.64, P=0.008); the risk for the combined variant genotypes (Ile/Val and Val/Val) of CYP1A1 exon7 was 1.61-fold (95% CI=1.24-2.08) (Z=3.62, P<0.001), compared with the Ile/Ile genotype; and that the risk for the GSTM1 null genotype was 1.54-fold (95% CI=1.31-1.80) (Z=5.32, P<0.001), compared with the GSTM1 present genotype. Therefore, in 46 published studies in Chinese populations, we found evidence of an association between the CYP1A1 variant and GSTM1 null genotypes and increased risk of lung cancer.     

淋巴瘤患者多环芳烃-DNA加合物及代谢酶基因细胞色素氧化酶P4501A1与谷胱苷肽硫转移酶M1基因多态性的研究

目的 探讨多环芳烃（PAH）-DNA加合物和代谢酶基因细胞色素氧化酶P4501A1（CYP1A1）与谷胱苷肽硫转移酶M1（GSTM1）基因多态性与淋巴瘤发病的关系.方法 通过竞争性酶联免疫吸附法测定54例淋巴瘤患者及34例对照组骨髓液中PAH-DNA加合物含量,采用限制性片段长度多态性PCR法（PCR-RFLP）测定上述标本CYP1A1、GSTM1基因多态性.结果 淋巴瘤患者骨髓液中PAH-DNA加合物含量为（2498±1 250） pg/ml,较对照组的（1 882±797） pg/ml增加,差异有统计学意义（t=0.006,P＜0.05）;淋巴瘤患者GSTM1基因型缺失占85.2％,对照组占58.8％,差异有统计学意义（x2=7.73,P＜0.05）,GSTM1基因型缺失者患淋巴瘤风险是GSTM1表达者的4.03倍（95％ CI1.51～10.76,P＜ 0.05）;CYP1A1变异型是野生型患淋巴瘤风险的1.36倍（95％CI 0.56～ 3.31,P＞ 0.05）,GSTM1缺失者PAH-DNA加合物水平≥2 200 pg/ml时患淋巴瘤的危险性增加（OR=9.53,95％CI 2.397～ 37.990,P＜ 0.05）.结论 PAH-DNA加合物可能参与淋巴瘤的发病,GSTM1缺失与淋巴瘤发生有关,并且增加患淋巴瘤的风险.     

Association of CYP1A1, CYP1A2, GSTM1 and NAT2 gene polymorphisms with colorectal cancer and smoking.

We investigated CYP1A1*2A, CYP1A1*2C, CYP1A2*1C, CYP1A2*1F, GSTM1 and NAT2 gene polymorphisms, involving enzymes which metabolize many carcinogens, with reference to colorectal cancer risk. The distribution of these genotypes was not associated with risk overall. However, the CYP1A1*2A T/C genotype showed a significant association with colorectal cancer risk in never-smokers (odds ratio [OR], 3.06; 95% confidence interval [95% CI], 1.11-8.40; p = 0.030). The risk of the NAT2 rapid genotype in never-smokers was also statistically significantly increased (OR, 5.38; 95%CI, 1.80-16.1; p = 0.003). Furthermore, the joint effects of NAT2 rapid plus other genotypes were associated with colorectal cancer overall (OR, 3.12; 95%CI, 1.15-8.51; p = 0.026, for NAT2 rapid plus combined CYP1A1*2C Ile/Val and Val/Val, OR, 3.25; 95%CI, 1.09-9.74; p = 0.035, for NAT2 rapid plus CYP1A2*1C G/G, and OR, 4.20; 95%CI, 1.09-16.1; p = 0.037, for NAT2 rapid plus GSTM1 null, respectively). In never-smokers, the joint effects of NAT2 rapid plus other genotypes were remarkable (OR, 15.9; 95%CI, 1.87-135.8; p = 0.011, for NAT2 rapid plus combined CYP1A1*2A T/C and C/C, OR, 5.71; 95%CI, 1.49-21.9; p = 0.011, for NAT2 rapid plus combined CYP1A1*2C Ile/Val and Val/Val, and OR, 9.14; 95%CI, 2.05-40.7; p = 0.004, for NAT2 rapid plus CYP1A2*1F A/A, respectively). The joint effect of CYP1A2*1F A/A plus CYP1A2*1C G/G genotypes was also increased in never-smokers (OR, 6.16; 95%CI, 1.26-30.1; p = 0.025). Our findings suggest that the CYP1A1*2A T/C and NAT2 rapid genotypes is associated with colorectal cancer susceptibility without smoking exposure. These results also indicate that the NAT2 in combination with CYP1A1*2C, CYP1A2*1C, or GSTM1 genotypes may strongly confer susceptibility to colorectal cancer. In particular, the combination of NAT2 plus CYP1A1*2A, CYP1A1*2C, or CYP1A2*1F genotypes, and that of CYP1A2*1F plus CYP1A2*1C genotype may define a group of persons who are genetically susceptible to colorectal cancer in never smokers.     

CYP1A1, GSTM1, and GSTT1 polymorphisms and breast cancer risk in Brazilian women

The frequency of CYP1A1 (CYP1A1*2A), GSTM1, and GSTT1 polymorphisms, as well as the main risk factors associated with breast cancer were studied in Brazilian women, with malignant breast cancer (n=128), or age-matched controls (n=256). Only a family history of breast cancer presented a significant risk (OR=3.00, CI=1.27-7.06). Among non-whites, the CYP1A1*2A allele was underrepresented among patients. Statistical analysis indicated that this polymorphism may decrease the risk of breast cancer among these individuals, particularly after adjusting for the risk presented by selected risk factors (OR=0.30, 95% CI=0.12-0.76).     

CYP1A1 CYP2E1 and GSTM1 polymorphisms are not associated with susceptibility to squamous-cell carcinoma of the esophagus

We investigated the genetic polymorphisms of CYPIAI, CYP2EI and GSTMI in Japanese esophageal cancer patients (n = 53) with a histological diagnosis of squamous-cell carcinoma, to determine whether susceptibility to esophageal cancer is associated with these polymorphisms. There were no significant differences in the frequency distribution of any one of the 3 polymorphisms between esophageal cancer patients and 132 healthy Japanese controls. The genotype distributions in tobacco smokers or alcohol drinkers were also quite similar for male patients and male controls. The age at onset of esophageal cancer was also similar for patients with any genotype of the 3 polymorphisms. We conclude that the 3 polymorphisms are unlikely to be associated with esophageal cancer susceptibility. Int. J. Cancer 71:192–195, 1997. © 1997 Wiley-Liss, Inc.     

Genetic effects on urinary 1-hydroxypyrene levels in a Korean population

Urinary 1-hydroxypyrene (1-OHP) has been used as a biomarker for assessing the level of exposure to environmental carcinogenic polycyclic aromatic hydrocarbons (PAHs). In order to perform the appropriate biological monitoring for examining the level of exposure to PAHs, this study investigated whether or not genetic polymorphisms of the metabolic enzymes, which might be involved in the metabolism of pyrene, affected the urinary 1-OHP levels in a population of 661 Koreans (male, 63%; female, 37%; mean age, 36.5 +/- 11.1 years) who were not occupationally exposed to PAHs. Urinary 1-OHP was detected in 76% of the subjects (range 0.001-3.8 micro g/l). Among the physical and lifestyle factors, cigarette-smoking was found to be associated with the urinary 1-OHP levels (P < 0.05). After adjusting for these factors, we found that the GSTT1 genotypes affected the urinary 1-OHP levels, i.e. the GSTT1 present subjects had approximately 1.5 times the urinary 1-OHP level than the GSTT1 null subjects (P < 0.05). In the case of the subjects who were also GSTM1 null, this trend became stronger, i.e. the GSTT1 present subjects had approximately 2 times the urinary 1-OHP level (P < 0.01). However, the genetic polymorphism of the other metabolic enzymes, cytochrome P-450 (CYP)1A1, CYP1B1 and GSTM1 alone, did not affect the urinary 1-OHP level. Therefore, this study suggests that the GSTT1 genetic polymorphism has the potential to affect the biological monitoring of PAHs with urinary 1-OHP, and might act as a genetic factor in PAH-related toxicity.     

Aromatic DNA adducts and polymorphisms of CYP1A1, NAT2, and GSTM1 in breast cancer

Previous studies by us and others have shown a significantly higher level of aromatic DNA adducts in normal adjacent breast tissue samples obtained from breast cancer patients than in those obtained from non-cancerous controls. The increased amount of DNA damage could be related to excess environmental carcinogen exposure and/or genetic susceptibility to such exposure. In the current study, we investigated the relationship between the levels of aromatic DNA adducts in breast tissues and polymorphisms of the drug-metabolizing genes cytochrome P4501A1 (CYP1A1), N-acetyltransferase-2 (NAT2), and glutathione S-transferase M1 (GSTM1), in 166 women having breast cancer. DNA adducts were measured using (32)P-postlabeling and information on smoking status was obtained from medical records. When pooled data of smokers and non-smokers were analyzed by multiple regression analyses, no significant correlation was found between the level of total DNA adducts and age, race, or polymorphisms of CYP1A1, GSTM1, and NAT2. The only significant predictor of the level of DNA adducts in breast tissues was smoking (P = 0.008). When data were analyzed separately in smokers and non-smokers, however, a significant gene-environment interaction was observed. Smokers with CYP1A1*1/*2 or *2/*2 genotypes had a significantly higher level of DNA adducts than those with the CYP1A1*1/*1 genotype. This effect was not seen among non-smokers. There was also a gene-gene interaction, as smokers with combined CYP1A1*1/*2 or CYP1A1*2/*2 genotypes and GSTM1 null had a much higher level of adducts than those with either CYP1A1 or GSTM1 polymorphism. Genetic polymorphisms of CYP1A1 and NAT2 were also significantly correlated with the frequency of certain types of DNA adducts. For example, a bulky benzo[a]pyrene (B[a]P)-like adduct was detected in 26% of the samples, the presence of which was not related to age, race, smoking status, or GSTM1 and NAT2 genotype. However, a significantly higher frequency of the B[a[P-like adduct was found in individuals having CYP1A1*1/*2 or *2/*2 genotypes than in those having the *1/*1 genotype (P = 0.04). In addition, individuals having slow NAT2 alleles had a significantly higher frequency of the typical smoking-related DNA adduct pattern, i.e. a diagonal radioactive zone (DRZ), than others did (P = 0.008). These findings suggest that polymorphisms of CYP1A1, GSTM1, and NAT2 significantly affect either the frequency or the level of DNA adducts in normal breast tissues of women having breast cancer, especially in smokers. Further large-scale studies are required to determine the exact role of these polymorphisms and types of DNA damage in breast cancer susceptibility.     

CYP1A1 and GSTM1 genetic polymorphisms and lung cancer risk in Caucasian non-smokers: a pooled analysis

Polymorphisms for genes encoding the metabolic enzymes cytochrome P450 1A1 (CYP1A1) and glutathione S-transferase M1 (GSTM1) might contribute to the variability in individual susceptibility to lung cancer. The role of CYP1A1 and GSTM1 in lung carcinogenesis might be more important at low levels of exposure to carcinogens. Non-smokers represent a population at low exposure, however, they are often overlooked because of the small number of cases. We therefore conducted a pooled analysis of 14 case-control studies on lung cancer in Caucasian non-smokers with comparable information on genetic polymorphisms included in the International Collaborative Study on Genetic Susceptibility to Environmental Carcinogens. We pooled the raw data from a total of 302 cases and 1631 controls with random effects models. We also evaluated the possibility of inclusion bias and conducted influence analyses. The odds ratio (OR) of lung cancer for the variant CYP1A1 Ile(462)Val polymorphism (Ile/Val, Val/Val) was 2.99 [95% confidence interval (95%CI) 1.51-5.91]; this effect was stronger on lung adenocarcinoma (OR 4.85, 95%CI 2.03-11.6). After excluding outlying or imprecise studies, we did not observe a significant effect of the CYP1A1 MspI (T(3801)C) polymorphism or GSTM1 null genotype (OR 1.20, 95%CI 0.89-1.63). Furthermore, our analyses suggested a combined effect of the CYP1A1 Ile(462)Val polymorphism and GSTM1 null genotype. The OR for the combination of the CYP1A1 Ile(462)Val variant and GSTM1 null genotype was 4.67 (95%CI 2.00-10.9) compared with the concurrent presence of the CYP1A1 wild-type and GSTM1 non-null genotype. We did not observe a modification of the effect of the GSTM1 null genotype according to exposure to environmental tobacco smoke and urban/rural residence. Our study therefore suggests that the CYP1A1 Ile(462)Val variant allele might play a role in lung carcinogenesis among non-smokers, possibly in combination with the GSTM1 null genotype.     

Susceptibility to oral cancer by genetic polymorphisms at CYP1A1, GSTM1 and GSTT1 loci among Indians: tobacco exposure as a risk modulator

Oral cancer is the leading cancer type among Southeast Asianmen and is causally associated with the use of tobacco. Geneticpolymorphisms in xenobiotic-metabolizing enzymes modify theeffect of environmental exposures, thereby playing a significantrole in gene–environment interactions and hence contributeto the high degree of variance in individual susceptibilityto cancer risk. This study investigates the role of polymorphismsat CYP1A1, GSTM1 and GSTT1 to oral squamous cell carcinoma (OSCC)in a case–control study involving 155 patients with precancerouslesions, 458 cancer patients and 729 age and habit-matched controls.Genotypes at these loci were determined by polymerase chainreaction (PCR) and PCR-restriction fragment length polymorphismperformed on genomic DNA extracted from peripheral blood lymphocytes.Risk to oral cancer was estimated among different tobacco exposuregroups and doses using logistic regression analysis. GSTM1 nullgenotype conferred 1.29-fold increased risk [95% confidenceinterval (CI), 1.04–1.65] to OSCC. GSTT1 null genotype,however, conferred 0.57 times reduced risk to OSCC (95% CI,0.39–0.83), specifically among tobacco chewers (odds ratio0.27; 95% CI, 0.14–0.53). This risk was further reducedto 0.13 times (95% CI, 0.04–0.46) with increase in lifetimeexposure to tobacco. We also investigated risk conferred bythese genotypes at two different intra-oral sites, buccal mucosaand tongue. We found increased susceptibility to buccal mucosacancer among individuals carrying these genetic markers. Theseresults support the finding that GSTM1 null genotype is a riskfactor to OSCC among Indian tobacco habits; GSTT1 null genotype,however, emerged as a protective factor. Abbreviations: CI, confidence interval; CYP, cytochrome p450; GSH, glutathione; GST, glutathione S-transferase; OR, odds ratio; OSCC, oral squamous cell carcinoma; PAH, polycyclic aromatic hydrocarbon; PCL, precancerous lesion; PCR, polymerase chain reaction; SCE, sister chromatid exchange Received October 18, 2006; revised February 8, 2007; accepted February 11, 2007.     

p53 mutations of lung cancer are not significantly affected by CYP1A1 or GSTM1 polymorphisms

Cytochrome p4501A1 gene (CYP1A1) and glutathione S-transferase mu gene (GSTM1) are involved in the metabolic activation or detoxification of environmental carcinogens including benzo[a]pyrene in tobacco smoke. Individuals with both Val/Val and C type of CYP1A1 (CYP1A1; Val/Val and CYP1A1; C) or homozygous null (-/-) genotype of GSTM1 gene (GSTM1; -/-) show increased susceptibility to lung cancer. The incidence of p53 gene mutations are related to the smoking index of the lung cancer patients. Therefore we determined genotypes of these enzymes and screened p53 gene mutations in 123 non-small cell lung cancer (NSCLC) patients. p53 gene mutations were found in 35% (43/123) of the patients. The incidence of p53 gene mutation CYP1A1; Val/Val (60.0%), CYP1A1; C (50.0%) tended to be higher than those of CYPIAI; Ile/Ile and Ile/Val (40.4%) or CYP1A1; A and B (40.5%). We conclude that the incidence of the p53 mutations does not seem to be significantly affected by only CYP1A1 or GSTM1 polymorphisms in lung cancer patients.     

CYP1A1和GSTM1基因多态性与内蒙古人群肺癌易感性的关系

背景与目的 肺癌是严重危害人类健康的恶性肿瘤之一，其发病与肺癌人群中某些肺癌相关基因的遗传多态性有关。本研究旨在探讨细胞色素P4501A1（CYP1A1）基因多态性和谷胱甘肽硫转移酶M1（GSTM1）基因多态性与内蒙古人群肺癌易感性的关系。方法 用PCR-RFLP技术分析了原发性肺癌组和住院对照组（各163例）的CYP1A1、GSTM1基因的多态性、基因型分布频率和交互作用。结果 CYP1A1突变型和GSTM1基因缺陷型EGSTM1（-）]频率分布分别为36．8％、65．0％（病例组）和19．0％、48．9％（对照组），二者经χ^2检验差异有显著性（χ^2=12．82，P=0．000；χ^2=9．78，P=0．002）。CYP1A1突变型患肺癌的风险显著增加（OR=2．48，95％CI为1．51～4．08）。GSTM1（-）者患肺癌的风险也显著增加（OR=2．03，95％CI为1．30～3．17）。基因突变的协同分析发现CYP1A1突变型／GSTM1（-）在肺癌组和对照组中的分布频率分别为28．8％和8．0％，二者经χ^2检验有显著性差异（χ^2=23．883，P=0．000）。CYP1A1突变型／GSTM1（-）患肺癌的风险显著增加（OR=4．90，95％CI为2．50～9．83）。无论是在肺癌组还是在对照组，CYP1A1突变型／GSTM1（-）和CYP1A1非突变型／GSTM1（-）在性别间分布频率的差异均无显著性（肺癌组χ^2=0．797，P=0．372；对照组χ^2=0．670，P=0．761）。吸烟与肺癌易感性的统计学分析，结果显示吸烟与肺癌易感性有关（χ^2=14．197，P=0．000），吸烟者患肺癌的风险显著增加（OR=2．33，95％CI为1.50～3．62）。CYP1A1突变型与吸烟关系的协同分析发现，携带CYP1A1突变型基因的吸烟者较携带CYP1A1突变型基因不吸烟者易患肺癌（OR=4．44，95％CI为2．40～8．32，χ^2=23．843，P=0．000）。GSTM1（-）与吸烟关系的协同分析中也发现，携带GSTM1（-）的吸烟者患肺癌的风险显著增加（OR=7．32，95％CI为3．39～15．50，χ^2=36．708，P=0．000）。结论 CYP1A1突变型和GSTM1（-）是内蒙古地区肺癌的易患因素，二者对肺癌的发生有协同作用，吸烟与肺癌的易感性也有关，CYP1A1突变型、GSTM1（-）与吸烟在肺癌的发生上也有相互促进作用。     

GSTM1, GSTP1, CYP1A1 and CYP2D6 polymorphisms in lung cancer patients from an environmentally polluted region of Poland: correlation with lung DNA adduct levels.

The CYP and GST genetic polymorphisms, controlling metabolism of xenobiotics, are considered to influence an individual's susceptibility to environmental and occupational carcinogens and predisposition to cancer. In the study, the effect of the GSTM1, GSTP1, CYP1A1 and CYP2D6 polymorphisms was investigated in relation to PAH-DNA adduct levels in non-tumourous lung tissue from non-small cell lung cancer (NSCLC) patients living in the industrialized region of Upper Silesia, Poland. The level of adducts among smokers was significantly elevated when compared to non-smokers (P = 0.0005). Adduct levels correlated inversely with age of patients (P = 0.00001). The GSTP1 and CYP2D6 polymorphisms had no influence on DNA adduct levels. There was a significant relationship between high adduct levels and the combined GSTM1 (null)/CYP1A1-Ile/Val genotype in the squamous cell carcinoma group (P = 0.028). An elevated number of adducts was found in patients with the GSTM1 (null)/CYP1Al-Ile/Val genotype compared to the GSTM1 (null)/CYP1A1-Ile/Ile carriers (P = 0.043). A higher frequency of the CYP1A1-Ile/Val and GSTM1 (null)/CYP1A1-Ile/Val genotypes was observed in patients with high adduct levels (P = 0.05 and P = 0.009, respectively). A significant prevalence of the GSTM1(null)/CYP1A1-Ile/Val carriers in the adenocarcinoma group was found (P = 0.003). Thus, our findings imply that the GSTMI and CYP1A1 exon 7 polymorphisms may influence PAH-DNA adduct levels in target tissue from NSCLC patients, especially in the squamous cell carcinoma group. Moreover, individuals carrying the GSTM1(null)/CYP1A1-Ile/Val genotype might exhibit a greater predisposition to a peripheral type of lung 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 cyto-chrome 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 Msp 1 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 Rsa 1 wild type versus those with combined GSTM1 non-null type and CYP2E1 variant allele. Our results suggest that CYP2E1 Rsa 1 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. (Cancer Sci 2003; 94: 448–452)     

Association of aryl hydrocarbon receptor gene polymorphisms and urinary 1-hydroxypyrene in polycyclic aromatic hydrocarbon-exposed workers

Polycyclic aromatic hydrocarbons (PAH) in coke oven emissions could cause lung cancer in human. Individual's genotype of the metabolic enzymes and early biological changes were known to be associated with the susceptibility of cancer development. Knowledge of metabolic gene polymorphisms, which affect on the urinary 1-hydroxypyrene (1-OHP), could benefit us in understanding the interindividual difference in the mechanism of PAH-induced carcinogenesis. In this study, we investigated the association of aryl hydrocarbon receptor (AhR) gene polymorphisms and urinary 1-OHP. One hundred forty-seven workers exposed to PAH and 69 nonexposure workers were recruited. Seven tagging single nucleotide polymorphisms in AhR gene were selected by pariwise r(2) method and minor allele frequency cutoff of 0.05 from Chinese genotype data in HapMap project. These seven tagging single nucleotide polymorphisms were genotyped by PCR-based methods. Multivariate analysis of covariance revealed that the levels of 1-OHP in PAH-exposed workers carrying genotype CT were lower than workers carrying wild genotype TT at loci rs10250822 and rs2282885 of AhR gene (P = 0.032 and 0.044, respectively). In PAH-exposed workers, the urinary 1-OHP levels showed a linear correlation (P(trend) = 0.041) with the genotypes at locus rs2282885, especially in low and moderate exposure groups. In contrast, no significant association was found between urinary 1-OHP level and AhR genotypes among nonexposed workers. Our findings indicated that polymorphisms of AhR gene were associated with the level of 1-OHP among PAH-exposed workers, suggesting that AhR-mediated signaling might contribute to individual susceptibility to PAH exposure.     

Ethnic susceptibility to lung cancer: differences in CYP2E1, CYP1A1 and GSTM1 genetic polymorphisms between French Caucasian and Chilean populations.

Many investigators have reported an association between genetic polymorphisms of cytochromes P-450 CYP2E1, CYP1A1 or glutathione S-transferase Mu (GSTM1) and susceptibility to lung cancer. However, pronounced interethnic variations have been described in the frequencies of these polymorphisms, especially between Asians and Caucasians. The present study was set up to establish CYP2E1 (c1, c2 and C, D), CYP1A1 (m1, m2 and Ile, Val) and GSTM1 (null) allelic frequencies in Chileans (n = 96) who are an admixture of Native Americans and Caucasians (Spaniards). The rare allele frequencies were found to be 0.15 (c2), 0.21 (C), 0.23 (m2), 0.32 (Val) and 0.21 ('null' genotype). These values are significantly higher than those of Caucasians except for the GSTM1 'null' genotype and suggest differences in susceptibility to lung cancer between both populations.