细胞色素P4502E1基因多态与贲门癌易感性关系探讨

 目的　探讨细胞色素P4 5 0 2E1(CYP2E1)基因多态与贲门癌易感性的关系。方法　采用病例对照研究方法和聚合酶链反应 限制性片段长度多态性 (PCR RFLP)检测技术 ,对 15 9例贲门癌患者和 192例对照的CYP2E1基因多态性进行分析。结果　CYP2E13种基因型在贲门癌病例组和对照组的分布差异有显著性 (χ2 =16 .0 4 ,P <0 .0 1) ,比值OR为 2 .37(95 %CI :1.5 2～ 3.70 )。贲门癌病例组CYP2E1(c1/c1)基因型频率为 6 0 .4 % ,对照组为 4 0 .1%。吸烟且携带CYP2E1(c1/c1)基因型的个体与携带CYP2E1(c1/c2或c2 /c2 )基因型的不吸烟者相比 ,患贲门癌的OR为 4 .6 8(95 %CI:2 .19～ 10 .0 4 )。结论CYP2E1基因多态性与贲门癌易感性有关 ,与吸烟协同作用使贲门癌的危险显著增加     

GSTM1、GSTT1基因多态性和吸烟与膀胱癌关系的病例对照研究

目的:应用全人群为基础的病例对照研究探讨GSTM1、GSTT1基因多态性和吸烟与膀胱癌危险性的关系。方法:采用多重PCR方法对404例正常对照和414例膀胱癌病例的基因组DNA进行GSTM1和GSTT1基因分型,应用非条件logistic回归分析方法进行统计分析。结果:与携带GSTM1( )基因型者比,GSTM1(-)基因型的男、女性患膀胱癌危险性分别为1.66(95%CI:1.18～2.33)和1.08(95%CI:0.59～1.98)。同样携带GSTM1(-)基因型,吸烟者比不吸烟者患膀胱癌的危险性更加明显。与不吸烟且携带GSTM1( )基因型男性比,GSTM1(-)基因型的目前吸烟者的OR值为2.99(95%CI:1.56～5.74),而携带GSTM1(-)基因型同时吸烟年限≥40年者OR为4.33(95%CI:2.14～8.73)。尽管女性吸烟例数较少,但携带GSTM1(-)基因型的吸烟女性患膀胱癌危险性显著高于不吸烟的GSTM1( )基因型者,OR值为6.72(95%CI:1.69～26.80)。与不吸烟且携带GSTT1( )基因型男性相比,携带GSTT1(-)基因型的吸烟者患男性膀胱癌危险的OR值为1.38(95%CI:0.79～2.42)。携带GSTT1(-)基因型的吸烟女性患膀胱癌危险性是不吸烟的GSTT1( )基因型者的3.04倍(95%CI:0.77～12.01)。结论:GSTM1(-)基因型能显著增加男性患膀胱癌的风险,该基因型与吸烟可能有一定的联合作用。GSTT1基因型可能与上海市区男、女性膀胱癌无关。     

GSTM1基因多态性与鼻咽癌遗传易感性的关系研究

目的　探讨谷胱甘肽S转移酶M 1(GSTM 1)基因多态性与鼻咽癌 (NPC )遗传易感性的关系。方法　采用内参照PCR法检测 80例NPC患者的GSTM 1基因型。结果　NPC患者GSTM 1空白基因型频率为 60 .0 % ,对照组为 45 .0 % ,两者有显著性差异 (P <0 .0 5 ) ,其OR =1.83 3 ( 95 %CI =1.0 46～ 3 .14 7) ;鳞癌的空白基因型频率为 60 .5 % ,明显高于腺癌的 5 0 .0 % (P <0 .0 1) ;吸烟者空白基因型个体患鼻咽癌的危险性显著增加 [OR =2 .813 ( 1.3 5 8～ 6.0 12 ) ,P <0 .0 1] ,而不吸烟者的危险性增加不明显 (P >0 .0 5 )。结论　GSTM 1基因多态性与NPC患者的遗传易感性有关 ,与NPC的病理类型有关 ,吸烟者的GSTM 1空白基因型个体更易患NPC。     

N-乙酰基转移酶基因多态性与肺癌的相关性

[目的]探讨N_乙酰基转移酶基因 (NAT2)多态性与肺癌易感性的关系。[方法]应用自动实时荧光Light_Cycler技术 ,分析76例肺癌患者和112例健康人NAT24个位点的基因多态性 ,比较肺癌患者与对照组间频率差异。[结果]肺癌组NAT2 *6A等位基因频率与对照组比较有显著性差异 ( χ2=7.025,P<0.05) ,使患肺癌的危险度提高了1.91倍 (P<0.05),且与吸烟有协同作用,在吸烟者肺癌中频率明显增高 ( χ2=10.437,P<0.01,0R=2.92);肺癌组NAT2其它等位基因频率和慢乙酰化基因型频率与对照组比较无显著性差异 (P>0.05)。[结论]NAT2 *6A等位基因增加了患肺癌的危险性,与吸烟有协同作用     

环境暴露、N-乙酰基转移酶-2基因多态性与大肠癌的关系

 目的　探讨N-乙酰基转移酶-2（NAT2）基因多态性及环境暴露与大肠癌易感性的关系。方法　以病例对照研究方法,采用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）基因分型技术,对86对大肠癌患者和非肿瘤患者（对照组）NAT2基因型进行测定。结果　NAT2慢速基因型在病例组的频率为19.58 %（56例）,对照组为10.14 %（29例）,差异具有统计学意义（χ2＝10.07,P＝0.00）。携带NAT2慢速基因型的个体患大肠癌的风险（OR）是携带快速基因型个体的2.16倍（95 % CI：1.31～3.54）。结论　NAT2基因多态性与大肠癌的易感性有关,携带慢速基因型的人群患大肠癌的风险增加。     

代谢酶基因多态性与肺癌易感性关系的研究

目的　探讨代谢活化酶细胞色素P45 0 1A1(CYP1A1)、2D6(CYP2D6)、2E1(CYP2E1)和代谢解毒酶谷胱甘肽硫转移酶 (GSTM 1)基因多态性与肺癌易感性的关系及重度吸烟对肺癌易感性的影响。方法　采用PCR、PCR RFLP等技术检测 180例原发性肺癌患者及 2 2 4例肺部良性疾病患者和正常人 (对照组 )外周血代谢酶基因型。结果　CYP1A1突变等位基因 (m )、CYP2D6野生型等位基因 (w )、CYP2E1A基因型和GSTM 1功能缺失型 ( -)可使患肺癌的危险性增加到 1.5 0～ 1.5 8倍 (P <0 .0 5 )。携带GSTM 1( -)者若同时携带CYP1A1、2D6或 2E1中任意 1个易感基因型 ,可使患肺癌的危险性升高到 2 .2 4～ 2 .69倍 (P <0 .0 5 )。携带相同基因型者 ,重度吸烟比不吸烟者患肺癌的危险性显著升高。重度吸烟人群中携带 4种易感基因型者患肺癌的危险性显著增高 ,达 9.85倍 ( 95 %CI =2 .3 0～ 45 .71)。结论　代谢酶基因的易感等位基因携带者患肺癌的危险性上升 ,且与烟草致癌物暴露剂量呈正相关。     

NQO1基因多态性与膀胱癌易感性的关系

[目的]探讨浙江地区依赖还原型辅酶Ⅰ/Ⅱ醌氧化还原酶1(NQO1)基因多态性与膀胱癌易感性的关系.[方法]采用病例对照研究方法,应用相对的两对引物—聚合酶链反应技术(PCR-CTPP),对99例膀胱癌患者和100例非肿瘤患者的NQO1 C609T基因型进行检测,并分析其与膀胱癌易感性的关系.[结果]NQO1 C609T基因型分布频率在膀胱癌组和对照组之间的差异具有统计学意义(P＜0.05),携带609TT基因型的个体罹患膀胱癌的风险是携带609CC基因型个体的2.448倍(95％CI为1.125～5.326).NQO1 C609T基因型分布频率在膀胱癌不同病理分级和临床分期之间的差异均无统计学意义(P＞0.05).[结论]NQO1 C609T基因多态性可能与膀胱癌的易感性相关,携带NQO1 609TT基因型的人群易患膀胱癌.     

DNA修复基因ERCC1多态性与肺癌易感性的关系

背景与目的最近研究发现DNA修复基因多态性可以影响到肿瘤的易感性,因此通过不同的DNA修复基因可筛选出肿瘤的易感人群,从而有望达到肿瘤的早期预防、诊断和治疗。本研究旨在分析DNA修复基因ERCC1多态性及其与肺癌易感性的关系。方法采用病例-对照研究,收集上海肺科医院原发性肺癌患者291例为病例组,同期住院的非肿瘤患者273例作为对照组,并进行流行病学调查。应用Taqman探针结合实时荧光PCR方法分析病例组和对照组的ERCC1基因T118C的多态性分布,比较不同基因型与肺癌易感性的关系,以及基因多态性与吸烟对肺癌的交互作用。结果在不吸烟人群中,ERCC1基因118位点3种基因型在病例组和对照组人群中分布差异有统计学意义(χ2=11.19,P<0.01)。在不吸烟人群中,与携带野生纯合基因型(C/C)相比,携带突变纯合基因型(T/T)者患肺癌的风险会增加,其校正OR值为3.16(95%CI:1.29-7.73,P<0.01)。以携带野生纯合基因型(C/C)且不吸烟者作为参照,吸烟>25包-年且携带野生纯合基因型(C/C)或杂合基因型(C/T)者患肺癌的风险均会提高,其校正OR值分别为2.62(95%CI:1.54-4.44)、2.41(95%CI:1.36-4.26,P<0.01)。以携带野生基因型者作为参照,携带突变纯合基因型者患腺癌的风险度会增加,其OR值为2.29(95%CI:1.05-4.78,P=0.03)。结论DNA修复基因ERCC1118C/T多态性可能对肺癌易感性产生影响,并可能与吸烟有一定的协同作用。     

GSTM1基因多态性和膀胱癌遗传易感性关系

目的：探讨谷胱甘肽转移酶（GSTMl）基因多态性与膀胱癌遗传易感性的关系。方法：采用面访填写调查表，以PCR技术、病例一对照研究方法，对252例病理证实原发膀胱移行细胞癌患者和320例健康对照者的GSTM1基因型进行检测。结果：膀胱癌患者GSTM1缺失基因型频率为45．2％。对照组为30．9％，两组比较差别有显著性意义（P〈0．05），OR值为1．89（95％CI=1．28～4．40）。吸烟者中，患者组GSTM1缺失基因型频率为66．2％，对照组为27．3％，差别显著（P〈0．01），OR值为8．9（95％CI=5．36～14．82）。同时憋屎及有家族肿瘤史也能增加患膀胱癌的危险性，但多饮牛奶则能降低膀胱癌的危险性，而水果摄入多少与膀胱癌发生危险性无统计学意义。结论：GSTM1基因多态性与膀胱癌易感性有关，该基因多态性与吸烟在膀胱癌的发生发展中起协同作用。     

NAT1、NAT2基因多态性与广东地区汉族人群喉癌遗传易感性研究

目的:探讨毒物代谢酶NAT1、NAT2基因多态性与广东地区汉族人群喉癌遗传易感性的关系。方法:采用病例-对照研究的方法,检测233例广东地区汉族喉癌和102例健康对照组外周血中NAT1(NAT1*4,NAT1*11,NAT1*10,NAT1*3)、NAT2(WT、M1、M2和M3)基因多态性。结合病历资料分析NAT1、NAT2多态基因与喉癌临床病理特征之间的关系。结果:喉癌患者携带NAT2快基因表型(18.88%)频率小于正常对照组(45.1%)(OR=2.53,P=0.00)。NAT2慢基因表型与重度吸烟在喉癌致病过程中有协同作用(P=0.013,OR=3.42)。NAT2基因表型与喉癌的临床病理特征无关。喉癌与对照组中NAT1多态基因频率无显著性差别。结论:NAT2快基因表型与喉癌的易感性关联,易感性与吸烟发生协同作用。NAT2基因多态性不影响喉癌的发展过程及预后。NAT1基因多态性可能与喉癌的遗传易感性无关。     

N-乙酰化转移酶2基因多态与喉癌遗传易感性的研究

目的 探讨N－乙酰化转移酶2（NAT2）基因多态与喉癌遗传易感性的 关系。方法 应用聚合酶链反应－限制性片段长度多态性分析（PCR－RFLP）方法,对62例喉癌患者进行研究,测定其NAT2基因型,按吸烟指数（SI）不同,分层分析患癌风险。并与56例非肿瘤患者进行对照。结果 喉癌组慢乙酰化型基因型频率为80．6％,对照组为60．7％,两者差异有显著性（χ^2=5.70,P=0.017)。高吸烟剂量组的NAT2慢乙酰化型个体,患喉癌风险明显高于低吸烟剂量组,在比值比（OR）分别为5．64和1．38,95％可信限（95％,CI）分别为1.77-17.92和0.42-4.52。结论 NAT2慢乙酰化型个体患喉癌风险增加,在喉癌发生过程中,NAT2慢乙酰化型个体患喉癌风险增加,在喉癌发生过程中,NAT2慢乙酰化型与吸烟有协同作用。     

Association of genetic polymorphisms of N-acetyltransferase 2 and susceptibility to esophageal cancer in north Indian population

Esophageal cancer is multifactorial disease involving environmental and genetic risk factors. Tobacco smoke and alcohol are strong environmental risk factors. N-acetyltransferase 2 (NAT2) is known to metabolize heterocyclic amine carcinogens in tobacco smoke. The purpose of this study was to determine whether genetic polymorphism in the NAT2 and their interaction with environmental factors influence the susceptibility for esophageal cancer. For our study, 126 patients and 164 controls were genotyped for NAT2 2 * 5, 2 * 6 and 2 * 7 polymorphisms using PCR-RFLP method. In a case-control study, NAT2 slow acetylator genotype was not significantly associated with risk of esophageal cancer (OR 1.3, 95%CI = 0.78-2.2, P = 0.28). There was significant linkage disequilibrium between 2 * 5-2 * 6 and 2 * 5-2*7 (P < 0.05). Using expectation maximization algorithm, 6 haplotypes were obtained but none of them revealed any significant contribution to disease susceptibility. In case only analysis, the smokers with rapid acetylator were at slightly higher risk of esophageal cancer (OR 1.3, 95%CI = 0.62-3.0, P = 0.43) which was not statistically significant. NAT2 slow or fast genotypes did not affect the risk of esophageal cancer in patients with alcohol consumption or occupational exposure. These results suggest that NAT2 acetylator genotypes did not influence the susceptibility to esophageal cancer. NAT2 polymorphism did not significantly modulate the cancer risk after interaction with environmental factors like tobacco, alcohol or occupational exposure.     

Genetic polymorphisms of N-acetyltransferase 1 and 2 and risk of cigarette smoking-related bladder cancer.

Aromatic amines from cigarette smoking or occupational exposure, recognized risk factors for bladder cancer, are metabolized by N-acetyltransferases (NAT). This study examined the association of (NAT) 1 and 2 genotypes with the risk of smoking-related bladder cancer. A total of 74 pathologically confirmed bladder cancer patients and 184 controls were serially recruited from the National Taiwan University Hospital. History of cigarette smoking and other risk factors for bladder cancer was obtained through standardized questionnaire interview. Peripheral blood lymphocytes were collected from each subject and genotyped for NAT1 and NAT2 by DNA sequencing and polymerase chain reaction-restriction fragment length polymorphism methods. Allele frequency distributions of NAT1 and NAT2 were similar between cases and controls. There was a significant dose-response relationship between the risk of bladder cancer and the quantity and duration of cigarette smoking. The biological gradients were significant among subjects carrying NAT1*10 allele or NAT2 slow acetylators, but not among NAT2 rapid acetylators without NAT1*10 allele. The results are consistent with the hypothesis that NAT1 and NAT2 might modulate the susceptibility to bladder cancer associated with cigarette smoking.     

Genetic polymorphisms of drug-metabolizing enzymes and susceptibility to head-and-neck squamous-cell carcinoma

We have investigated the association between the polymorphisms of drug-metabolizing enzymes and susceptibility to head-and-neck squamous-cell carcinoma (HNSCC). PCR-based analysis was performed on 145 Japanese patients and 164 healthy Japanese controls to determine genotypes of polymorphisms in CYP1A1, CYP2E1, GSTM1, GSTP1, and NAT2. Patients and controls were compared by multivariate analysis. The CYP1A1 Val/Val genotype was seen more frequently in patients than in controls [odds ratio (OR) 4.1, p = 0.038). The frequency of the slow plus intermediate NAT2 genotypes was also higher in patients (OR 2.0, p = 0.039). When we analyzed the distributions of the genotypes in 69 laryngeal and 45 pharyngeal cancer patients, laryngeal cancer patients had a higher frequency of NAT2 slow or intermediate genotype (OR 2.7, p = 0.011) and GSTP1 AA genotype (OR 2.4, p = 0.047) than controls. Pharyngeal cancer patients had a higher frequency of the CYP1A1 Val/Val genotype than controls (OR 5.7, p = 0.034), suggesting that different organs may be responsive to different chemicals from the environment. Furthermore, 23 patients who developed multiple cancers (HNSCC plus other) were compared with 115 patients with HNSCC alone. There was no significant difference in the polymorphisms between the 2 groups, though excessive alcohol consumption (more than 50 g/day of ethanol) appeared to be a risk factor for multiple cancers (p = 0.053).     

Molecular genetics and epidemiology of the NAT1 and NAT2 acetylation polymorphisms.

The focus of this review is the molecular genetics, including consensus NAT1 and NAT2 nomenclature, and cancer epidemiology of the NAT1 and NAT2 acetylation polymorphisms. Two N-acetyltransferase isozymes, NAT1 and NAT2, are polymorphic and catalyze both N-acetylation (usually deactivation) and O-acetylation (usually activation) of aromatic and heterocyclic amine carcinogens. Epidemiological studies suggest that the NAT1 and NAT2 acetylation polymorphisms modify risk of developing urinary bladder, colorectal, breast, head and neck, lung, and possibly prostate cancers. Associations between slow NAT2 acetylator genotypes and urinary bladder cancer and between rapid NAT2 acetylator genotypes and colorectal cancer are the most consistently reported. The individual risks associated with NAT1 and/or NAT2 acetylator genotypes are small, but they increase when considered in conjunction with other susceptibility genes and/or aromatic and heterocyclic amine carcinogen exposures. Because of the relatively high frequency of some NAT1 and NAT2 genotypes in the population, the attributable cancer risk may be high. The effect of NAT1 and NAT2 genotype on cancer risk varies with organ site, probably reflecting tissue-specific expression of NAT1 and NAT2. Ethnic differences exist in NAT1 and NAT2 genotype frequencies that may be a factor in cancer incidence. Large-scale molecular epidemiological studies that investigate the role of NAT1 and NAT2 genotypes and/or phenotypes together with other genetic susceptibility gene polymorphisms and biomarkers of carcinogen exposure are necessary to expand our current understanding of the role of NAT1 and NAT2 acetylation polymorphisms in cancer risk.     

Glutathione S-transferase (GST) M1, T1 and N-acetyltransferase 2 (NAT2) polymorphisms and urothelial cancer risk with tobacco smoking.

The objective of this study was to examine the association between the genetic polymorphism of glutathione S-transferase (GST) M1, T1 and N-acetyltransferase 2 (NAT2) genes and urothelial cancer risk in relation to smoking status. In this study, 325 Japanese patients with urothelial transitional cell carcinoma and 325 healthy controls were compared for frequencies of GSTM1, T1 and NAT2 genotypes. The frequencies of GSTM1 null genotype and NAT2 slow genotype were significantly higher in the cases than in the controls (adjusted odds ratio (OR) 1.37, 95% confidence interval (CI) 1.01-1.87, adjusted OR 3.09, 95% CI 1.69-5.63, individually). Furthermore, the risk of GSTM1 null genotype and NAT2 slow genotype was higher among smokers (adjusted OR 1.48, 95% CI 1.01-2.15, adjusted OR 4.28, 95% CI 1.96-9.36, individually). The regression analysis of cancer risk as a function of the amount of smoking showed that the susceptibility of people who had GSTM1 null genotype increased from 45 pack-years, while the susceptibility of people with NAT2 intermediate or slow genotype increased rapidly from 25 pack-years, compared with non-smokers. A multiplicative interaction between NAT2 intermediate or slow genotype and pack-years of smoking was found (P<0.001), but GSTM1 null genotype was not (P=0.06). Our results indicate that the GSTM1 null genotype and NAT2 intermediate or slow genotype are associated with an increased risk of urothelial cancer in relation to smoking amounts. Furthermore, the interaction between NAT2 intermediate or slow genotype and pack-years of smoking has a strong impact on urothelial cancer.     

Association between N-acetyltransferase 2 (NAT2) genetic polymorphism and development of breast cancer in post-menopausal Chinese women in Taiwan, an area of great increase in breast cancer incidence.

The incidence of breast cancer has increased greatly in Taiwan over the past 2 decades. Increased exposure to environmental carcinogens, including aryl aromatic amines, as a result of the economic boom, is suspected to be one factor contributing to this increase. The enzyme N-acetyltransferase 2 (NAT2) determines the rate of metabolism of aryl aromatic amines, and therefore the NAT2 slow acetylator genotype is associated with an increased risk of cancer. Our present case-control study of 150 breast cancer patients and 150 healthy controls in Taiwan was performed to explore the association between NAT2 genetic polymorphism and individual susceptibility to breast cancer. A structured questionnaire was used to collect relevant information regarding all known or suspected risk factors of breast cancer. The NAT2 genotype was determined using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay in 139 cases and 133 controls, and 28.8% and 21.1%, respectively, were found to have slow acetylator genotypes. Multivariate analysis, simultaneously considering other risk factors, including age at menarche, nulliparity or age at first full-term pregnancy, body mass index (BMI), hormone replacement therapy (HRT) and smoking status, showed that the NAT2 slow acetylator genotype was associated with an increased risk with borderline significance (Odds Ratio, 1.81; 95% CI, 1.01-3.31). Interestingly, this association was not significant in premenopausal women, but was significant in post-menopausal women. Further stratification of our study subjects based on different risk factor status showed that the increased risk for an NAT2 slow acetylator was more marked in post-menopausal women who were not using HRT or who had a lower BMI. Our findings suggest that NAT2 polymorphism is a susceptibility factor for breast cancer in Taiwanese women, and that NAT2-metabolized carcinogens are probably present in the environment and may be associated with induction of breast cancer.     

N-acetyltransferase (NAT1, NAT2) and glutathione S-transferase (GSTM1, GSTT1) polymorphisms in breast cancer

To evaluate the potential association between NAT1/NAT2 polymorphisms and breast cancer, a case-control study was conducted in Korean women (254 cases, 301 controls). NAT1 *4/*10 genotype (42%) was the most common NAT1 genotype in this Korean population. The frequencies of slow, intermediate and rapid NAT2 acetylator genotype were 16, 39 and 44% in cases and 16, 42 and 42% in controls. Neither NAT1 rapid (homozygous or heterozygous NAT1 *10) (OR=1.2, 95% CI=0.8-1.9) nor NAT2 rapid acetylator genotype (OR=1.2, 95% CI=0.8-1.7) showed significant association with breast cancer risk. Although the risk of NAT2 rapid acetylator genotype in postmenopausal women (OR=1.4, 95% CI=0.7-2.8) was higher than that in premenopausal women (OR=1.1, 95% CI=0.7-1.7), those were not statistically significant. However, combinations of NAT1, GSTM1 and GSTT1 genotypes showed a significant linear gene-dosage relationship with breast cancer (p for trend=0.04) and those women with NAT2 rapid acetylator and both GSTM1 and GSTT1 null genotypes were at the elevated risk (OR=3.1, 95% CI=1.0-9.1). These results suggest that genetic polymorphisms of NAT1 and NAT2 have no independent effect on breast cancer risk, but they modulate breast cancer risk in the presence of GSTM1 and GSTT1 null genotypes.