GSTM1, GSTT1, and GSTP1 polymorphisms, breast cancer risk factors and mammographic density in women submitted to breast cancer screening

Genetic polymorphisms in genes related to the metabolism of xenobiotics, such as genes of the glutathione S-transferases (GSTM1, GSTT1, and GSTP1) superfamily have been associated with an increased risk for breast cancer (BC). Considering the high incidence of BC in the city of Porto Alegre in southern Brazil, the purpose of this study was to characterize genotypic and allelic frequencies of polymorphisms in GSTM1, GSTT1, and GSTP1, and correlate these molecular findings with established risk factors for breast cancer including mammographic density, in a sample of 750 asymptomatic women undergoing mammographic screening. Molecular tests were performed using the multiplex polymerase chain reaction (PCR) for GSTM1 and GSTT1, and quantitative PCR for GSTP1 polymorphisms. Overall, the frequencies of GSTM1 and GSTT1 null genotypes were 45% and 21%, respectively. For GSTP1 polymorphism, genotypic frequencies were 44% for the Ile/Ile genotype, 44% for the Ile/Val genotype, and 12% for Val/Val genotype, with an allelic frequency of 66% for the wild type allele in this population, similar to results of previous international publications. There was a statistically significant association between the combined GSTM1 and GSTT1 null genotypes (M-/T-) and mammographic density in post menopausal women (p = 0.031). When the GSTT1 null (T-) genotype was analyzed isolated, the association with mammographic density in post menopausal women and in the overall sample was also statistically significant (p = 0.023 and p = 0.027, respectively). These findings suggest an association of GSTM1 and GSTT1 null genotypes with mammographic density.     

铀矿工GSTP1基因多态与MGMT基因和p16基因甲基化的关系

目的探讨氡职业暴露人群谷胱甘肽S-转移酶P1(GSTP1)基因多态与痰细胞6-氧-甲基嘌呤-DNA甲基转移酶(MGMT)和p16基因甲基化的关系。方法用聚合酶链反应-限制性片段长度多态性法(PCR-RFLP)确定70例氡职业暴露人群GSTP1的基因型;用聚合酶链反应-甲基化特异性法(MSP)确定痰细胞中MGMT和p16基因的甲基化与非甲基化状态。结果在70名铀矿工中,GSTP1基因A105G位点的纯合子(Ile/Ile)42例,杂合子(Ile/Val)25例和纯合子(Val/Val)3例。MGMT、p16基因甲基化率和总甲基化率分别为14.2%、8.6%和18.6%。与携带Ile/Ile人群相比,携带异常等位基因(Ile/Val与Val/Val)的人群MGMT基因甲基化和总甲基化率增加[P=0.037,OR=4.8,95%CI(1.1~21.0);P=0.016,OR=5.1,95%CI(1.4~19.6)];p16基因甲基化率差异无统计学意义[P=0.057,OR=4.6,95%CI(0.8~29.2)]。结论GSTP1(A105G)基因多态性与氡致MGMT基因甲基化和总甲基化的易感性有关。     

Cruciferous vegetables, the GSTP1 Ile105Val genetic polymorphism, and breast cancer risk

BACKGROUND: Cruciferous vegetables are the primary source of isothiocyanates and other glucosinolate derivatives that are known to induce phase II detoxifying enzymes, including glutathione S-transferases (GSTs). OBJECTIVE: We investigated the independent and combined effects of cruciferous vegetable intake and the GSTP1 Ile(105)Val genetic polymorphism on breast cancer risk. DESIGN: Analyses included 3035 cases and 3037 population controls who were participating in the Shanghai Breast Cancer Study and for whom diet and genetic data were complete (87% of cases and 85% of controls). RESULTS: With the use of multivariate logistic regression, the GSTP1 Val/Val genotype was significantly associated with greater breast cancer risk (OR = 1.50; 95% CI: 1.12, 1.99). The association was significantly greater in premenopausal women (OR = 1.69; 95% CI: 1.17, 2.43) than in postmenopausal women (OR = 1.20; 95% CI: 0.74, 1.92). Total cruciferous vegetable intake was not significantly associated with breast cancer risk, although subjects reporting greater turnip (P for trend < 0.001) and Chinese cabbage (P for trend = 0.049) intakes had a significantly lower postmenopausal breast cancer risk. Women with the GSTP1 Val/Val genotype and low cruciferous vegetable intake had a breast cancer risk 1.74-fold (95% CI: 1.13, 2.67) that of women with the Ile/Ile or Ile/Val genotype. This effect of low cruciferous vegetable intake and the Val/Val genotype was seen predominantly among premenopausal women (OR = 2.08; 95% CI = 1.20, 3.59). CONCLUSIONS: Cruciferous vegetable intake consistent with high isothiocyanate exposure may reduce breast cancer risk. Cruciferous vegetable intake also may ameliorate the effects of the GSTP1 genotype.     

Smoking and the risk of lung cancer: susceptibility with GSTP1 polymorphisms

BACKGROUND: GSTP1 is a gene that helps detoxify foreign substances in the body. Functional polymorphisms of GSTP1 have been studied as risk factors for lung cancer. Past studies have compared the effect of the "at risk" polymorphism in two strata of smoking pack-years (usually defined by the median among controls). We examined the interaction between GSTP1 polymorphisms and cumulative exposure to smoking and their association with lung cancer risk. METHODS: Data are from a large hospital-based case-control study of persons treated for primary lung cancer at the Massachusetts General Hospital since 1992. Controls were drawn from friends and nonrelated family members. We genotyped 1,042 cases and 1,161 controls for GSTP1 using polymerase chain reaction-restriction fragment length polymorphism techniques. FINDINGS: The GSTP1 GG genotype approximately doubled the lung cancer risk associated with pack-years. This interaction was stronger among current smokers. At 26 pack-years (median among controls with a smoking history), the adjusted odds ratio for the association between pack-years and lung cancer risk was 13 (95% confidence interval = 6.5-25) among current smokers with the GSTP1 GG genotype compared with 6.1 (95% confidence interval = 4.9-7.5) among those with the GSTP1 AA genotype. CONCLUSIONS: GSTP1 GG increases the lung cancer risk associated with pack-years of smoking.     

Pooled analysis and meta-analysis of the glutathione S-transferase P1 Ile 105Val polymorphism and bladder cancer: a HuGE-GSEC review

The glutathione S-transferase P1 genotype (GSTP1) is involved in the inactivation of cigarette smoke carcinogens, and sequence variation in the gene may alter bladder cancer susceptibility. To examine the association between GSTP1Ile 105Val and bladder cancer, the authors undertook a meta- and pooled analysis. Summary crude and adjusted odds ratios and corresponding 95% confidence intervals were pooled by using a random-effects model. In the meta-analysis (16 studies, 4,273 cases and 5,081 controls), the unadjusted summary odds ratios for GSTP1 Ile/Val and Val/Val compared with GSTP1 Ile/Ile were 1.54 (95% confidence interval: 1.21, 1.99; p < 0.001) and 2.17 (95% confidence interval: 1.27, 3.71; p = 0.005). The association appeared to be the strongest in Asian countries. When the analysis was limited to European descendents (nine studies), the summary odds ratio decreased (odds ratio = 1.24, 95% confidence interval: 1.00, 1.52) (Q = 17.50; p = 0.02). All relevant data previously contributed to the International Study on Genetic Susceptibility to Environmental Carcinogens were pooled (eight studies, 1,305 cases and 1,558 controls). The summary odds ratios were similar to the ones from the meta-analysis. Case-only analyses did not detect an interaction between the GSTP1 genotype and smoking status (never/ever). GSTP1 Ile 105Val appears to be associated with a modest increase in the risk of bladder cancer.     

焦炉工代谢酶和DNA修复酶基因多态性与DNA损伤的关系

目的研究外源性化学物代谢酶和DNA损伤修复酶基因多态性与焦炉作业工人外周血淋巴细胞DNA损伤易感性的关系。方法选取144名焦炉作业工人(暴露组)和50名医务人员(对照组)作为研究对象,测定其尿中1-羟基芘浓度来反映多环芳烃暴露内剂量,用碱性彗星试验评价个体外周血淋巴细胞DNA损伤,分析细胞色素P4501A1、细胞色素P4502E1、谷胱甘肽S-转移酶P1(GSTP1)、还原型辅酶2-醌氧化还原酶、环氧化物水化酶和XRCC1基因的多态性,以及不同基因型与DNA损伤的关系。结果暴露组尿中1-羟基芘浓度为11．8μmol／mol肌酐、彗星尾矩为3．2,均高于对照组(尿中1-羟基芘浓度为0．7μmol／mol肌酐、彗星尾矩为1．1);暴露组中XRCC1 Arg280His位点变异基因型个体的彗星尾矩(5．6)显著高于野生型个体(2．8)。以1．74为界值,将全部研究对象的彗星尾矩转化为分类变量后的回归分析结果表明,XRCC1 Arg280His位点变异基因型个体发生DNA损伤的危险度显著高于野生基因型个体;GSTP1 Ile104Val位点变异基因型个体发生DNA损伤的危险度高于野生基因型个体,但差异无统计学意义。结论XRCC1 280His和GSTP1 104Val等位基因可增加职业性多环芳烃暴露导致的外周血淋巴细胞DNA损伤水平。     

细胞色素P4501A1基因多态性与食管癌易感性关系的Meta分析

目的 探讨细胞色素P4501A1(CYP1A1)MspI和Ile/Val位点基因多态性与食管癌发生的关系.方法 采用Meta分析方法,对国内外1997-2008年采用病例对照方法研究CYP1A1MspI和Ile/Val基因多态性与食管癌发生关系的16篇(MspI 8篇,Ile/Val 14篇)文献,采用显性模型(即突变基因型与野生型比较)进行综合定量分析,然后按病理分型(鳞癌/腺癌)分亚组进行分析.结果 综合分析CYP1A1 MspI突变基因型(TC+CC)与食管癌发生无统计学关联(OR=1.17,95%CI:0.82～1.66),亚组分析亦未发现CYP1A1 MspI突变基因型与食管鳞癌(OR=1.17,95%CI:0.82～1.69)和食管腺癌(OR=1.39,95%CI:0.67～2.09)的统计学关联;携带CYP1A1突变基因型(Ile/Val+Val/Val)的个体发生食管癌的危险性是野生型的1.39倍(OR=1.39,95%CI:1.07～1.80);亚组分析显示突变基因型与食管鳞癌发生的易感性相关但与食管腺癌无关联,OR值分别为1.43(95%CI:1.07～1.91)和1.20(95%CI:0.62～2.30).结论 CYP1A1 Ile/Val位点突变基因型可增加食管鳞癌发生的危险性,CYP1A1 MspI位点基因多态性与食管癌无关联.     

氯乙烯作业工人染色体损伤及其遗传易感性

目的 探讨氯乙烯(VCM)致染色体损伤与DNA修复基因和代谢酶基因多态间的关系.方法 收集上海某化工厂402名VCM接触工人健康体检资料、人口学资料(年龄和性别)、生活方式(吸烟、饮酒)和职业接触等因素,评估个人VCM累积接触剂量并分组.采集静脉血3 ml,采用外周血淋巴细胞胞质分裂阻滞微核试验(CBMN)检测染色体损伤,采用聚合酶链式反应(PCR)检测GSTT1、GSTM1基因缺失情况,采用PCR-限制性片段长度多态性技术(RFLP)检测其他基因多态.结果 多元Poisson回归分析结果表明,中(4000～40000 mg)、高(＞40000 mg)VCM接触剂量组染色体损伤的风险明显高于低剂量组,调整后的FR值分别为1.19(1.06～1.34)和1.20(1.06～1.38),差异有统计学意义(P值分别为0.003和0.01);携带CYP2E1和XRCC1 Arg280His突变型基因的个体微核率明显高于野生型个体,调整后的FR值分别为1.12(1.02～1.23)和1.13(1.02～1.25),差异有统计学意义(P值均为0.02);携带GSTP1Val/Val和ALDH2 Glu/Glu基因型个体微核率明显高于其他基因型个体,调整后的FR值分别为0.74(0.59～0.94)和0.87(0.79～0.95),差异有统计学意义(P值分别为0.01和0.003).结论 VCM致染色体损伤与VCM累积接触剂量增高及GSTP1 Val/Val、CYP21E1 c1c2/c2c2、ALDH2 Glu/Glu、XRCC1 280His/His 或Arg/His基因型多态性等因素有关.开展VCM致染色体损伤与遗传易感性方面的研究,有助于VCM致癌机制的阐明,而研究中易感性多态位点的发现也可以为识别易感人群提供理论依据.     

联合分析XRCC1、XPD和GSTP1基因单核苷酸多态性在铂类药物化疗敏感性中的预测作用

目的 联合分析X线修复交叉互补基因1（X-rayCOrSS—complementing1,XRCCl）第194和399位点,着色性干皮病基因D（XerodermapigmentosumgroupD,XPD）第312位点及谷胱甘肽-s-转移酶P1基因（GlutathioneS-Transferasepl,GSTPl）第105位点的单核苷酸多态性（singlenucleotidepolymorphisms,SNPs）在预测铂类药物化疗敏感性中的作用。方法采用基因测序法对50例恶性肿瘤患者的外周血进行XRCCl、XPD和GSTPl基因单核苷酸多态性（SNPs）检测,分析各基因型与铂类药物化疗敏感性的关系。结果有效率高的基因型为：XRCC1194位点的Arg／Trp和Trp／Trp,XRCC1399位点的Arg／Arg,XPD312位点的Asn／Asn,GSTPl105位点的Val／Val,它们的化疗有效率分别为57．1％、75．0％、60．9％、85．7％、87．5％。有两个以上和有1个或0个高效基因型患者的化疗有效率分别是78．9％、36．4％和0,有两个以上高效基因型的患者的敏感性明显高于有1个或0个高效基因型的患者,其差异有统计学意义（x2=25．79,P〈0．01）。结论对XRCC1、XPD和GSTP1基因的单核苷酸多态性进行联合检测,可能预测患者对铂类药物的敏感性。     

Polymorphisms in glutathione-related genes affect methylmercury retention

Methylmercury is eliminated from the human body as glutathione (GSH) conjugates. GSH production is mediated by glutamyl-cysteine ligase (GCL) and conjugation by glutathione S-transferases (GST). In this study, the authors tested whether polymorphisms in GCL and GST genes modify methylmercury retention. Erythrocyte mercury concentration (EryHg), plasma polyunsaturated fatty acids (PPUFA), and genotype for GCLC, GCLM, GSTA1, GSTM1, GSTP1, and GSTT1 were determined in 365 individuals. A general linear model was developed for analyzing whether genotype modified the regression of EryHg on PPUFA. The presence of one variant allele for either GCLC-129 or GSTP1-114 was associated with higher EryHg and steeper regression slope. No similar trends were shown for GCLM, GSTA1, GSTM1, or GSTT1. These findings indicate that GCLC polymorphisms that affect GSH production also affect methylmercury retention, and that GSTP1 may play a role in conjugating methylmercury with GSH.     

Genetic variation in glutathione-related genes and body burden of methylmercury

BACKGROUND: Exposure to toxic methylmercury (MeHg) through fish consumption is a large problem worldwide, and it has led to governmental recommendations of reduced fish consumption and blacklisting of mercury-contaminated fish. The elimination kinetics of MeHg varies greatly among individuals. Knowledge about the reasons for such variation is of importance for improving the risk assessment for MeHg. One possible explanation is hereditary differences in MeHg metabolism. MeHg is eliminated from the body as a glutathione (GSH) conjugate. OBJECTIVES: We conducted this study to assess the influence of polymorphisms in GSH-synthesizing [glutamyl-cysteine ligase modifier subunit (GCLM-588) and glutamyl-cysteine ligase catalytic subunit (GCLC-129)] or GSH-conjugating [glutathione S-transferase pi 1 (GSTP1-105 and GSTP1-114)] genes on MeHg retention. METHODS: Based on information obtained from questionnaires, 292 subjects from northern Sweden had a high consumption of fish (lean/fat fish two to three times per week or more). We measured total Hg in erythrocytes (Ery-Hg) and long-chain n-3 polyunsaturated fatty acids in plasma (P-PUFA; an exposure marker for fish intake). RESULTS: The GSTP1 genotype modified Ery-Hg; effects were seen for GSTP1-105 and -114 separately, and combining them resulted in stronger effects. We found evidence of effect modification: individuals with zero or one variant allele demonstrated a steeper regression slope for Ery-Hg (p=0.038) compared with individuals with two or more variant alleles. The GCLM-588 genotype also influenced Ery-Hg (p=0.035): Individuals with the GCLM-588 TT genotype demonstrated the highest Ery-Hg, but we saw no evidence of effect modification with increasing P-PUFA. CONCLUSIONS: These results suggest a role of GSH-related polymorphisms in MeHg metabolism.     

The glutathione S-transferase θ and μ deletion polymorphisms in asbestosis

The glutathione S-transferases (GSTs) catalyze the conjugation of a wide variety of reactive, electrophilic substrates with glutathione, facilitating their excretion. There is also evidence that GSTs can catalyze glutathione conjugation of lipid radicals as well as act in the generation of leukotriene inflammatory mediators. Studying construction carpenters screened for the presence of asbestos-related diseases, we have previously reported that the constitutional deletion of GSTM1 (the gene coding for glutathione S-transferase class mu) is associated with an increased risk of asbestos-related interstitial lung disease, measured radiographically. In the current work, we have further studied this group of workers, investigating the distribution of a novel deletion polymorphism in the newly described GSTT1 gene, that codes for the GST class theta enzyme. A total of 666 carpenters were studied, and 124 (19%) had the deleted genotype. There was no association between the GSTT1 deletion and the radiographic diagnosis of either asbestos-related pleural or parenchymal disease. The GSTM1 deletion remained associated with the presence of x-ray evidence of asbestosis after adjustment for GSTT1 genotype. The GSTM1 null genotype was also associated with a family history of any malignancy. These data suggest that the association of polymorphic GSTs with asbestos-induced radiographic changes is specific for substrates of the GST class mu. Am. J. Ind. Med. 31:274–279, 1997. © 1997 Wiley-Liss, Inc.     

MPO、NQO1、GSTP1和UGT1A6基因多态与慢性苯中毒遗传易感性关系

目的探讨MPO、NQO1、GSTP1和UGT1A6基因多态与慢性苯中毒易感性的关系。方法采用病例-对照研究,以268名苯中毒工人为病例组,268名接触苯而没有中毒表现的工人为对照组。应用TaqManPCR分析技术判定MPO(rs7208693),NQO1(rs1800566),GSTP1(rs947894)和UGT1A6(rs6759892,rs1105879,rs4124874,rs3755319,rs887829和rs4148323)基因型。结果携带GSTP1基因rs947894G等位基因个体患慢性苯中毒的危险性比AA基因型个体降低0.657倍(95%CI0.434~0.994,P=0.046);携带MPO基因rs7208693A等位基因人群中,UGT1 A6 rs6759892G等位基因个体发生慢性苯中毒的危险性是TT基因型的2.702倍(P=0.024),UGT1 A6 rs1105879C等位基因个体发生慢性苯中毒的危险性是TT型的2.619倍(P=0.035)。在饮酒人群中,携带NQO1基因rs1800566TT基因型个体慢性苯中毒的发病风险较携带CC和CT基因型个体增加9.000倍(95%CI1.460~55.478,P=0.021);在吸烟人群中,带NQO1基因rs1800566TT基因型个体慢性苯中毒的发病风险较携带CC和CT基因型个体增加7.000倍(95%CI1.555~31.575,P=0.012)。单倍型分析显示,本人群携带UGT1A6基因TACGGG单倍型个体慢性苯中毒的发病风险是携带TAATGG单倍型个体的1.446倍(OR=1.446,95%CI1.005~2.080,P=0.046)。结论同时携带MPO基因rs7208693A和UGT1A6基因rs6759892G或rs1105879C等位基因型个体对苯中毒易感;携带NQO1基因rs1800566TT基因型且同时吸烟或饮酒的个体对苯中毒易感;携带UGT1A6基因TAATGG单倍型个体可增加慢性苯中毒的发病风险;GSTP1基因多态与慢性苯中毒遗传易感性的关系仍需进一步研究。     

Glutathione S-transferases GSTM1 and GSTT1 polymorphisms and asbestosis

OBJECTIVE: In a nested case-control study, the authors investigated whether the deletion polymorphism of glutathione S-transferases GSTM1 and GSTT1 represents a risk factor for the development of asbestosis. METHODS: In total, 262 cases with asbestosis and 265 controls, selected from a cohort of 2080 workers occupationally exposed to asbestos, were genotyped for GSTM1 and GSTT1-null alleles. Cumulative exposure for each subject was available. RESULTS: Asbestosis was associated with cumulative exposure (odds ratio [OR]=3.21, confidence interval [CI] 2.43-4.23) and GSTT1-null genotype (OR=0.61, CI 0.40-0.94), but not with GSTM1-null genotype (OR=1.01, CI 0.71-1.43). The risk of GSTM1-null and GSTT1-null genotype for asbestosis did not change after adjustment by cumulative exposure, smoking, gender, and age. CONCLUSIONS: An important finding of this study is that GSTT1 gene deletion might have a protective effect on the development of asbestosis.     

Association of Xenobiotic Metabolizing Enzymes Genetic Polymorphisms With Esophageal Cancer in Kashmir Valley and Influence of Environmental Factors

The Kashmir Valley has an elevated incidence rate of esophageal cancer (EC). Several environmental and genetic factors have been suspected for development of EC. A case-control study was performed in 135 EC patients and 195 healthy controls to analyze association of polymorphisms in glutathione S-transferase (GST) mu (GSTM1), GST theta (GSTT1), GST pi (GSTP1), GSTM3, Cytochrome P450 (CYP)1A1, and CYP2E1 genes with susceptibility to EC as well as their interaction with environmental factors such as smoking and high consumption of salted tea in Kashmir valley. All subjects were genotyped through polymerase chain reaction restriction fragment length polymorphism. Data was statistically analyzed using the chi-square test and logistic regression model. Results showed that GSTP1313 val/val and CYP2E1c1c2 genotypes imparted risk for esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma [EADC; odds ratio (OR) = 3.24, 95% confidence interval (CI) = 1.30–8.05; OR = 4.20, 95% CI = 1.65–10.70], respectively. GSTM3AB genotype/B allele was found to be associated with low risk for EC. Tobacco smoking through hukka (water pipe) and consumption of salted tea itself were high risk factors for developing EC (OR = 21.44, 95% CI = 11.63–39.54; OR = 14.86, 95% CI = 8.41–26.24), and the risks were modulated through the interaction of GSTM3AB, GSTP1val/val genotypes. In conclusion, GSTP1val/val and CYP2E1c1c2 genotypes/c2 allele increased the risk of ESCC and EADC, respectively, in the Kashmiri population; whereas GSTM3AB genotype imparted lower risk for both ESCC and EADC.     

大肠癌代谢酶基因多态性的Meta分析

目的 综合评价代谢酶基因多态性与大肠癌危险性的关系。方法 应用Meta分析原理对国内42篇大肠癌相关代谢酶基因多态性的病例研究进行定量综合分析。统计处理采用M-H法或D-L法以及RevM4.1统计软件包。结果 GSTM1缺陷型，GSTT1缺陷型，GSTP1Llel105Val,NAT1*10,NAT2快速乙酰化表型/基因型，乙酰化表型，乙酰化基因型，CYP1A1MspI,CYP1A1Lle462Val,MTHFRC677T和MTRA2759G11个研究因素的综合统计量（OR值）分别为1.06,1.42,1.09,1.25,1.08,1.15,1.05,1.26,1.30,0.83和0.60。结论 GSTT1缺陷型，NAT2快速乙酰化表型/基因型和NAT2快速乙酰化表型可能与大肠癌的发生有关。     

焦炉作业工人外周血淋巴细胞染色体损伤的遗传易感性研究

目的研究外源性化学物代谢酶基因多态性与焦炉作业工人外周血淋巴细胞染色体损伤的关系。方法选取149名焦炉作业工人和24名非职业多环芳烃(PAH)暴露人员作为研究对象,测定其尿中1-羟基芘浓度来反映PAH暴露的内剂量;对照组的外周血淋巴细胞微核水平的上4分位数(6‰)作为判断个体染色体损伤阳性的界值;分析CYP1A1、GSTM1、GSTT1、GSTP1、CYP2E1、NQO1、NAT2和mEH基因的多态性;使用多元logistic回归方程校正职业暴露情况、年龄、性别、吸烟和饮酒状况因素,计算不同基因型工人发生染色体损伤阳性的OR值,并探讨基因间的交互作用。结果调整了173名研究对象的职业暴露、年龄、性别、吸烟和饮酒状况后,GSTM1缺失基因型个体染色体损伤危险度显著性增加(调整OR=2．01,95％CI=1．03—3.91);与NQO1基因P187S位点野生型纯合子个体比较,变异型纯合子个体染色体损伤危险度显著性增加(调整OR=3．18,95％CI=1．18—8．62);与mEH基因H113Y位点野生型纯合子个体比较,变异型纯合子个体染色体损伤危险度显著性降低(调整OR=0．40,95％CI=0.19～0．88);未发现其他基因的遗传变异与研究对象外周血淋巴细胞染色体损伤危险度的显著关联。此外,还发现GSTM1、NQO1基因P187S位点和mEH基因H113Y位点的遗传变异对染色体损伤危险度的影响中存在基因-基因交互作用。结论本研究发现GSTM1、NQO1和mEH基因的遗传变异可显著性影响职业PAH暴露个体外周血淋巴细胞染色体损伤危险度,并存在基因一基因交互作用。     

CYP1A1基因多态性和GSTM1缺失与肺癌易感性的关系

[目的]探讨CYPlAl基因异亮氨酸(Ile)-缬氨酸(Val)位点多态性和GSTMl缺失与肺癌易感性的关系。[方法]以病例-对照方法,采用PCR技术检测82例原发性肺癌患者和91例对照者的CYPlAl基因Ile-Val位点多态性与GSTMl基因的缺失。[结果]Ile-Val3种多态基因型在肺癌组和对照组分布差异有显著性(P<0.05),Ile／Val、Val／Val基因型在肺癌组的分布频率明显高于对照组;logistic回归分析结果显示Ile／Val、Val／Val基因型患肺癌的危险性分别是Ile／Ile基因型的1.969(95％CI:1.012-3.828)倍和3.150倍(95％CI:1.278-7.761);GSTMl基因缺失在两组的分布频率差异有显著性(P<0.05,OR=2.157)。进一步联合CYPlAl多态性分析显示GSTMl缺失的个体同时携带Ile／Val或Val／Val基因型患肺癌的危险性较单独具有一种危险因子患肺癌的危险性显著增加(OR=5.538)。[结论]CYPlAl第7外显子的Ile／Val、Val／Val基因型和GSTMl缺失与肺癌的易感性有关,可望作为肺癌易感人群筛选的重要指标。     

GSTT1 genotype modifies the association between cruciferous vegetable intake and the risk of myocardial infarction

BACKGROUND: Cruciferous vegetables are a major dietary source of isothiocyanates that may protect against coronary heart disease. Isothiocyanates induce glutathione S-transferases (GSTs), polymorphic genes that code for enzymes that conjugate isothiocyanates, as well as mutagens and reactive oxygen species, to make them more readily excretable. OBJECTIVE: The objective of the study was to determine whether GST genotypes modify the association between cruciferous vegetable intake and the risk of myocardial infarction (MI). DESIGN: Cases (n = 2042) with a first acute nonfatal MI and population-based controls (n = 2042) living in Costa Rica, who were matched for age, sex, and area of residence, were genotyped for a deletion polymorphism in GSTM1 and GSTT1 and an Ile105Val substitution in GSTP1. Cruciferous vegetable intake and smoking status were determined by questionnaire. Odds ratios (ORs) and 95% CIs for MI were estimated by unconditional logistic regression. RESULTS: Compared with the lowest tertile of cruciferous vegetable intake, the highest tertile was associated with a lower risk of MI among persons with the functional GSTT1*1 allele (OR: 0.70; 95% CI: 0.58, 0.84) but not among those with the GSTT1*0*0 genotype (OR: 1.23; 95% CI: 0.83, 1.82) (P = 0.006 for interaction). This protective effect among those with the GSTT1*1 allele was greater for current smokers (OR: 0.54; 95% CI: 0.36, 0.79) than for nonsmokers. GSTP1 and GSTM1 did not modify the association between cruciferous vegetable intake and MI. CONCLUSIONS: Consumption of cruciferous vegetables was associated with a lower risk of MI among those with a functional GSTT1*1 allele, which suggests that compounds that are detoxified by this enzyme contribute to the risk of MI.