被动吸烟孕妇胎儿GSTM1、GSTT1及CYP1A1基因多态性对胎儿出生畸形的影响

目的探讨被动吸烟孕妇胎儿谷胱甘肽S转移酶M1(GSTM1)、谷胱苷肽硫转移酶T1(GSTT1)及细胞色素P450(CYP1A1)基因多态性对胎儿出生畸形的影响。方法 2009年1月至2014年12月选取在本院分娩、单胎活产出生畸形的新生儿85名为研究组,另选取同期在本院分娩的185例单胎活产正常新生儿为对照组,采用PCR技术检测两组新生儿GSTM1、GSTT1及CYP1A1基因型,运用多因素模型进行交换作用分析。结果研究组新生儿GSTM1、GSTT1基因缺失型及CYP1A1基因多态突变型频率显著高于对照组(P0.05)。通过多因素模型进行交换作用分析可知,母亲孕期被动吸烟分别与GSTM1、GSTT1基因缺失型及CYP1A1基因多态突变型有正相加模型交互作用。交互效应超额相对危险度(RERI)分别为9.85、8.12、3.26,效应指数(S)分别为1.98、1.79、1.65。结论 GSTM1、GSTT1基因缺失型及CYP1A1基因多态突变型与孕妇孕期被动吸烟存在相加模型交互作用,可能与胎儿先天发育异常的发生有密切关系。     

GSTT1基因型和吸烟状况与肺癌易感性关系

 目的：探讨GSTT1基因多态性与肺癌遗传易感性的关系及GSTT1基因多态性和性别、吸烟在肺癌易感性中的交互作用。方法：采用病例对照和PCR-RFLP)方法对100例肺癌患者和135例健康对照者外周血的GSTT1基因型进行检测,并评价其与吸烟和肺癌遗传易感性的关系。 结果：(1)GSTT1(-)基因型在肺癌组和对照组分别为57%和41.5%,二者间有显著性差异( P=0.019)。GSTT1(-)基因型的吸烟者较不吸烟者患肺癌的风险增加3.643倍(P=0.016)。吸烟者携带GSTT1(-)基因型较携带GSTT1(+)基因型患肺癌的风险增加3.286倍(P=0.006)。吸烟量≥20包年的人群中携带GSTT1(-)基因型者较携带 GSTT1(+)基因型者患肺癌的风险增加7.81倍(P=0.002)。结论：GSTT1(-)基因型增加肺癌遗传易感性,吸烟与GSTT1(-)基因型间存在互交作用,二者协同增加患肺癌的风险性。吸烟量越大且携带GSTT1(-)基因型者患肺癌的风险越高     

汉族人群谷胱甘肽-S-转移酶M1、T1基因多态性分析

目的 分析汉族人群谷胱甘肽-S-转移酶M1、T1(GSTM1,GSTT1)的基因多态性分布。方法样本为60名唐山地区汉族人群，采用多重等住基因聚合酶链反应(PCR)方法分析GSTM1和GSTT1基因多态性。结果 GSTM1缺失型和GSTT1缺失基因型频率分别为33．3％和11．7％，同时具有GSTM1缺失型和GSTT1缺失型的个体频率为1．7％。结论唐山地区GSTM1,GSTT1基因呈多态性分布，其等位基因和基因型频率不同于其他种族。     

蒙古族谷胱甘肽S-转移酶GSTT1和GSTM1基因多态性

目的 探讨内蒙古地区蒙古族谷胱甘肽S-转移酶(glutathione S-transferase GSTs EC 2.5.1.18) GSTM1和GSTT1基因多态性分布特点,为内蒙古少数民族基因型研究提供相关数据。 方法 采用内对照聚合酶链反应技术（PCR）和凝胶成像分析方法,对555例内蒙古地区蒙古族个体的GSTT1、GSTM1基因缺失型频率进行了分析。结果 GSTM1基因缺失型、GSTT1缺失型在内蒙古地区蒙古族人群中检出频率分别为55.7%和65.9%。同时具有GSTM1缺失型和GSTT1缺失型个体的 检出频率为32.2%。结论 中国蒙古族人群GSTM1、GSTT1基因呈多态性分布,与汉族及其他少数民族存在一定差异。     

壮族人群少精不育患者精细胞GSTT1和GSTM1基因研究

目的:探讨壮族人群精细胞GSTT1和GSTM1基因多态性与少精症的关系。方法:应用PCR法对75名壮族少精不育患者及36名健康男性精细胞GSTT1和GSTM1基因进行多态性研究,探讨该基因对少精症的影响。结果:实验组GSTM1基因及GSTM1+GSTT1组合的缺失型基因高于对照组,差异有统计学意义(P0.05)。结论:壮族人群精细胞GSTM1基因和GSTT1+GSTM1基因多态性与男性少精症有着较为密切的联系,其具体作用机制有待进一步研究。     

汉族儿童Ⅱ相药物代谢酶基因GSTM1和GSTT1的多态性分布

目的了解谷胱甘肽-S-转移酶M1（GSTM1）和T1（GSTT1）基因多态性在中国汉族儿童中的分布特点,为临床针对不同基因型个体化药物治疗提供理论基础。方法选择首都医科大学附属北京儿童医院健康查体汉族儿童的血样,提取DNA。应用PCR法检测GSTM1和GSTT1基因型,并判断代谢表型。检索PubM ed等数据库,获得亚洲人群、黑种人和高加索人群GSTM1和GSTT1基因多态性分布的数据,与本研究分析人群数据进行比较,分析基因多态性的种族差异。结果 786份研究样本纳入分析。①中国汉族分析人群GSTM1和GSTT1完全缺失基因型/慢代谢型（＊0/＊0）的频率分别为59.3%（466/786例）和58.4%（459/786例）;单拷贝缺失基因型/中间代谢型（＊1/＊0）的频率分别为34.0%（267/786例）和35.1%（276/786例）;未缺失基因型/快代谢型（＊1/＊1）的频率分别为6.7%（53/786例）和6.5%（51/786例）。②GSTM1和GSTT1基因多态性分布互相独立,无明显关联。③GSTM1和GSTT1基因多态性无显著性别差异。④本研究汉族分析人群GSTM1和GSTT1基因多态性分布与亚洲人群较为接近,与黑种人和高加索人群有显著差异。结论 GSTM1和GSTT1基因在中国汉族儿童中以完全缺失基因型/慢代谢型（＊0/＊0）为主,具有种族特异性,为不同基因型个体制定合适的用药方案提供了参考依据。     

细胞代谢解毒酶CYP1A1、GSTM1基因多态性与吸烟对男性肺鳞癌发病的影响

 目的 探讨细胞代谢解毒酶细胞色素P450酶1A1（CYP1A1）、谷胱甘肽S-转硫酶M1（GSTM1）基因多态性和吸烟因素对男性肺鳞癌发病的影响。方法 采用基因芯片技术对125例男性肺鳞癌患者和125例男性健康对照者CYP1A1、GSTM1基因多态性进行检测。结果 CYP1A1 m2位点GG基因型和GSTM1缺失基因型在肺鳞癌组与健康对照者间存在显著性差异(P<0.05 )。吸烟者携带CYP1A1 m2位点至少一个变异G等位基因或携带GSTM1缺失型者患肺鳞癌的危险性进一步显著增加,OR值分别为4.50和3.81(P<0.01)。结论 吸烟与CYP1A1、GSTM1基因多态性与男性肺鳞癌的发生有关。     

CYP1A1和GSTM1基因多态性与BPDE-DNA加合物的关系及其对肺癌的影响

目的 分析代谢酶基因细胞色素氧化酶P450(cytochrome P450,CYP450)1A1与谷胱苷肽硫转移酶M1(glutathione S-transferase μ1,GSTM1)的多态性和二羟环氧苯并芘(benzo A-pyrene-diolepoxide,BPDE)-DNA加合物之间的关系,并探讨其对肺癌发病的影响.方法 用病例-对照方法收集200例原发性肺癌患者的流行病学调查资料及外周血样本,采用限制性片段长度多态性-PCR法检测血中CYP1A1、GSTM1基因多态性,应用竞争性酶联免疫吸附法检测BPDE-DNA加合物浓度.结果 CYP1A1变异型吸烟者、GSTM1缺失型吸烟者患肺癌风险升高,OR值分别为2.406(1. 321～4. 382)和2.755(1.470～5.163).肺癌患者BPDE-DNA加合物浓度高于对照人群,且肺癌吸烟者加合物浓度明显高于肺癌不吸烟者(P=0.0252);GSTM1缺失型个体DNA加合物水平高于5.0加合物/108核苷酸时,患肺癌的风险升高(OR=1.988,95％ CI:1.011～3.912);CYP1A1变异型吸烟者形成高水平DNA加合物的风险明显高于CYP1A1野生型不吸烟者(P=0.0459); GSTM1缺失型吸烟者形成高水平DNA加合物的风险高于GSTM1功能型不吸烟者(OR=2.432,95％ CI:1.072～4.517).结论 GSTM1缺失型个体DNA加合物水平高更容易增加肺癌危险性;CYP1A1变异型吸烟者、GSTM1缺失型吸烟者更容易形成高水平的DNA加合物,对肺癌的发生可能有重要影响.     

韩国人CYP450 1A1、CYP450 2E1和GSTM1、GSTT1、GSTP1基因座遗传多态性分析

目的 调查代谢相关的CYP4501A1、CYP4502E1和GSTM1、GSIT1、GSTP1基因座在韩国人群中的遗传多态性分布状况。方法 采用多重聚合酶链式反应、聚合酶链式反应-限制性片段长度多态性技术，分析300名韩国健康大学生的CYP1A1基因3′端限制性内切酶Msp Ⅰ位点、CYP2E1基因5′端转录调节区Pst Ⅰ位点和GSTM1、GSTT1缺失与存在、GSTP1基因第5外显子BsmA Ⅰ位点的基因型，计算基因型和基因频率。结果 CYP1A1基因型频率为ml／ml型39．7％、ml／m2型49．7％、m2／m2型10．7％，基因频率为ml 0．645、m2 0．355。CYP2E1基因型频率为cl／cl型66．7％、cl／c2型30％、c2／c2型3．3％，基因频率为C1 0．818、C2 0．182。GSTM1基因缺失型频率为53．3％。GSTT1基因缺失型频率为54．7％。GSTP1基因型频率为Ile／Ile型62％、Ile／Val型34．3％、VaL／Val型3．7％，基因频率为Ile 0．792、Val 0．208。基因分布符合Hardy-Weirtberg平衡定律。结论 韩国人CYP1A1、CYP2E1、GSTM1、GSTT1基因分布与我国人群较为相近，半数以上人缺乏GSTM1和GSTT1基因，纯合缺失型频率超过印度人的3倍。     

北京地区汉族人群DNA修复基因XPD单核苷酸多态性与肺癌及食管癌风险的研究

目的：研究核苷酸切除修复基因XPD单核苷酸多态性与北京地区汉族人群肺癌及食管癌风险的关系。方法：采用以医院患者为基础的病例－对照研究方法，包括正常对照383人，肺癌患者351例，食管癌患者325例。以聚合酶链反应－限制性片段长度多态性方法分析了XPD基因Asp312 Asn和Lys751Gln多态性，比较不同基因型与肺癌及食管癌风险的关系，并探讨吸烟与基因多态交互作用对患癌风险的影响。结果：与携带312 Asp/Asp基因型者比较，携带至少1个312Asn等位基因者（即Asp/Asn和Asn/Asn基因型）罹患肺鳞癌的风险增加1．8倍（95％CI1．10－2．93），而与肺腺癌无关（校正的比值比为1．07，95％CI0．55－2．08）。分层分析显示，风险型等位基因312Asn和751Gln与吸烟有明显的交互作用。吸烟剂量≥29包／年且携带312Asn或751Gln者罹患肺鳞癌的风险最高，校正的比值比分别为12．44（95％CI4．97－31．17）和10．74（95％CI4．51－25．57）。XPD基因Asp312Asn和Lys751Gln多态与食管鳞癌风险无关。结论：XPD基因Asp312Asn和Lys751Gln多态是地区汉族人群肺鳞癌遗传易感因素，而与肺腺癌以及食管鳞癌风险无关，可能反映了不同组织学类型肺癌以及肺癌和食管癌之间的病因学差异。     

GSTT1 Gene Deletion Is Associated with Lung Cancer in Mexican Patients

Glutathione S-transferase (GST) is a dimeric detoxifying isoenzyme, involved in the deactivation of carcinogens, several tobacco-derived carcinogens, and xenobiotics. It catalyzes the reduction of glutathione to its thioester; thus, deficiency in GST activity due to homozygous deletion of the GSTT1 gene (null genotype) may play a role in the induction of lung cancer by smoking.We studied the distribution of GSTT1 gene deletion in peripheral blood DNA samples from 178 healthy controls (41 nonsmokers, 63 passive smokers and 74 smokers) and 52 lung cancer patients. Comparisons between groups showed that there was an increased lung cancer risk for individuals with the GSTT1 null genotype. Cancer patients showed significant differences when compared with controls: nonsmokers, passive smokers, and smokers. Twenty-one percent of lung cancer patients carried the deletion versus 2% among nonsmokers not exposed to passive smoking, 6% among passive smokers, and 5% among smokers. Thus, there is a significant association between this genotype and the possibility to risk of developing lung cancer.     

GSTT1 gene deletion is associated with lung cancer in Mexican patients

Glutathione S-transferase (GST) is a dimeric detoxifying isoenzyme, involved in the deactivation of carcinogens, several tobacco-derived carcinogens, and xenobiotics. It catalyzes the reduction of glutathione to its thioester; thus, deficiency in GST activity due to homozygous deletion of the GSTT1 gene (null genotype) may play a role in the induction of lung cancer by smoking. We studied the distribution of GSTT1 gene deletion in peripheral blood DNA samples from 178 healthy controls (41 nonsmokers, 63 passive smokers and 74 smokers) and 52 lung cancer patients. Comparisons between groups showed that there was an increased lung cancer risk for individuals with the GSTT1 null genotype. Cancer patients showed significant differences when compared with controls: nonsmokers, passive smokers, and smokers. Twenty-one percent of lung cancer patients carried the deletion versus 2% among nonsmokers not exposed to passive smoking, 6% among passive smokers, and 5% among smokers. Thus, there is a significant association between this genotype and the possibility to risk of developing lung cancer.     

The role of glutathione transferases M1 and T1 in individual susceptibility to bladder cancer in a Tunisian population

BACKGROUND: Susceptibility to bladder cancer is thought to depend on interplay between genetic factors and environmental chemical carcinogens. AIM: This study seeks to determine the role of the glutathione transferases M1 and T1 null genotypes (GSTM1*0 and GSTT1*0) in individual susceptibility to bladder cancer in a Tunisian population. METHOD: Sixty-two patients with transitional cell carcinoma of the bladder cancer and 79 controls were examined with respect to the frequency of GSTM1 and GSTT1 null genotypes. RESULTS: The frequencies of the GSTT1 null in the total group of bladder cancer cases vs. controls did not differ statistically. The proportion of GSTM1 null genotype in patients was 63% compared to 45% in controls group (OR = 2.03; 95% CI 0.97-4.24; p = 0.04). A significantly higher incidence of GSTM1 deletion genotype was found in smokers with bladder cancer compared to the controls (65.38% vs. 45.5%). Smokers lacking the GSTM1 gene are at an approximately 2.2-fold higher risk of bladder cancer (OR= 2.23, 95% CI 1-5.15; p = 0.03). CONCLUSION: This study suggests that in Tunisian subjects the GSTM1 null genotype may be associated with an increased risk of bladder cancer. This association appears to depend upon smoking status.     

Interaction of glutathione-s-transferase genotypes with environmental risk factors in determining susceptibility to head and neck cancer and treatment response and survival outcome

The present case-control study aimed to investigate the role of interaction of glutathione-s-transferase (GST) genotypes with environmental risk factors in determining susceptibility to head and neck squamous cell carcinoma (HNSCC) involving 1,250 cases and equal number of healthy controls. An increase in the risk of HNSCC and its subsites (larynx, pharynx, and oral cavity) was observed among the cases with null genotypes of GSTM1 (odds ratio [OR] = 1.87) or GSTT1 (OR = 1.39) while reduced risk (OR = 0.81) was observed the cases with variant genotype of GSTP1. Tobacco use in the form of smoking or chewing interacted multiplicatively with GSTM1 or GSTT1 to increase the risk several folds (3–10 folds) in HNSCC and its subsites. Alcohol use also increased the risk (2–3 folds) to HNSCC and its subsites in cases with null or variant genotypes of GSTs, though this risk was of lesser magnitude when compared to the tobacco users. A synergistic effect of both, tobacco smoking and alcohol drinking, led to several folds (25-folds) increased risk to HNSCC among the cases with null genotype of GSTM1 and GSTT1 when compared to nonsmokers and nondrinkers with wild genotype of GSTM1 and GSTT1 in controls. Furthermore, cases with variant genotypes of GSTP1 (Val/Val) showed superior treatment response with improved survival rate and lower risk of death when compared to the patients with wild type genotype (Ile/Ile). The data suggest that though polymorphism in GSTs may be a modest risk factor for determining HNSCC risk, gene-environment interactions significantly modify the susceptibility to HNSCC by several folds.     

Possible risk modification by CYP1A1, GSTM1 and GSTT1 gene polymorphisms in lung cancer susceptibility in a South Indian population

Susceptibility to lung cancer has been shown to be modulated by inheritance of polymorphic genes encoding cytochrome P450 1A1 (CYP1A1) and glutathione S transferases (GSTM1 and GSTT1), which are involved in the bioactivation and detoxification of environmental toxins. As the incidence of lung cancer is known to differ according to ethnicity, we have conducted a case-control study of 146 South Indian lung cancer patients along with 146 healthy controls, to assess any association between CYP1A1, GSTM1 and GSTT1 polymorphisms, either separately or in combination, with the likelihood of development of lung cancer in our population. The current weight of evidence from our study indicated that the frequency of CYP1A1 MspI homozygous variant alleles was significantly higher in cases (OR=3.178). We observed a considerable difference in the GSTT1 null deletion frequency in this population when compared with other populations (OR=2.472, 95% CI: 1.191–5.094, P=0.014). There was no relative risk in GSTM1 null genotype when analysed singly (P=0.453). Considering genotype combinations, risk of lung cancer increased remarkably significantly in individuals having one variant allele of CYP1A1, GSTM1, or GSTT1, suggesting gene–gene interactions. Rare genotypic combinations (such as CYP1A1 wild GSTM1 or GSTT1 either null; CYP1A1 variant both GSTM1 and GSTT1 present; CYP1A1 variant GSTM1 or GSTT1 either null), were at higher risk compared to the reference group. Moreover, patients who had smoked <20 pack years and harboured the CYP1A1 variant allele or the GSTT1 null genotype also had a significant risk of lung cancer. Hence our study—the first to analyse a South Indian population—suggests the importance of combined CYP1A1, GSTM1 and GSTT1 polymorphisms in the development of smoking-induced lung cancer.     

The role of glutathione transferases M1 and T1 in individual susceptibility to bladder cancer in a Tunisian population

Background: Susceptibility to bladder cancer is thought to depend on interplay between genetic factors and environmental chemical carcinogens.

Aim: This study seeks to determine the role of the glutathione transferases M1 and T1 null genotypes (GSTM1*0 and GSTT1*0) in individual susceptibility to bladder cancer in a Tunisian population.

Method: Sixty-two patients with transitional cell carcinoma of the bladder cancer and 79 controls were examined with respect to the frequency of GSTM1 and GSTT1 null genotypes.

Results: The frequencies of the GSTT1 null in the total group of bladder cancer cases vs. controls did not differ statistically. The proportion of GSTM1 null genotype in patients was 63% compared to 45% in controls group (OR?=?2.03; 95% CI 0.97–4.24; p?=?0.04). A significantly higher incidence of GSTM1 deletion genotype was found in smokers with bladder cancer compared to the controls (65.38% vs. 45.5%). Smokers lacking the GSTM1 gene are at an approximately 2.2-fold higher risk of bladder cancer (OR?=?2.23, 95% CI 1–5.15; p?=?0.03).

Conclusion: This study suggests that in Tunisian subjects the GSTM1 null genotype may be associated with an increased risk of bladder cancer. This association appears to depend upon smoking status.     

Interactive effect of the glutathione S-transferase genes and cigarette smoking on occurrence and severity of coronary artery risk

Cardiovascular diseases and cancer are the main causes of death in developed countries. Mortality trends for these diseases suggest that they share common pathogenetic mechanisms. Glutathione S-transferase (GST) is a family of enzymes that detoxify reactive electrophiles, particularly present in tobacco smoke. Glutathione S-transferase null M1 and T1 (GSTM1 and GSTT1) genotypes have often been associated with increased risk of developing cancer. Our hypothesis was that the polymorphic GSTM1 and GSTT1 genes modulate the risk of smoking-coronary artery disease (CAD). We evaluated the distribution of GST genotypes in 430 angiographically defined patients (308 CAD and 122 non-CAD). The frequencies of GST null genotypes did not differ significantly between patients with CAD and without CAD. However, smokers with GSTM1 and GSTT1 null genotypes had a significantly higher risk of CAD than never-smokers with these genotypes present (OR 2.2 and 3.4 for smokers with null GSTM1 and GSTT1 genes, respectively). There was also evidence of multiple interaction between GSTM1 and GSTT1 deleted genotypes and smoking. In nonsmokers carrying both null genotypes the risk of CAD was 0.66. In smokers with both present genotypes the OR was 1.5 and was significantly increased in smokers with concurrent lack for GSTM1 and GSTT1 genes (OR=4.0). Moreover, smokers lacking GST genes had both more stenosed vessels and a higher Duke score than smokers expressing the genes. We also examined the levels of DNA damage in 66 men patients using the micronucleus test, a sensitive assay for evaluating chromosome damage. Micronucleus levels were higher in smokers with null genes than in smokers with present genes. These observations suggest that GST-null genotypes strengthen the effect of smoking on CAD risk by modulating the detoxification of genotoxic atherogens.     

Strong association between the GSTM1-null genotype and lung cancer in a Turkish population

Glutathione S-transferases are possibly related to the detoxification of many xenobiotics involved in the etiology of cancer. To investigate the role of the glutathione S-transferase M1 deletion (GSTM1-null) in lung cancer, the polymerase chain reaction was used to determine the GSTM1 genotypes of lung cancer patients (n=101) and hospital (n=206) in a Turkish population. The prevalence of the GSTM1-null genotype in the case group was 48%, compared to 18% in the control group, giving an odds ratio (OR) of 4.14 (95% confidence interval [CI]=2.36-7.27). The analysis of patients by histologic type of lung cancer (10% adenocarcinoma, 43% squamous cell carcinoma, 26% small cell carcinoma, and 11% large cell carcinoma) showed no association between histopathologic type of lung cancer and GSTM1-null genotype. When the interaction between the GSTM1-null genotype and smoking status was analyzed, among the 67 smokers, the GSTM1-null genotype was found in 37 (55%) with an OR of 2.58 (95% CI=1.00-6.73) indicating a significant association. However, no association was found between smoking exposure (<30 and > or =30 packs/year) and GSTM1-null genotype. We conclude that, in this study the null GSTM1 genotype is an independent risk factor for the development of lung cancer for Turkish population.     

Glutathione S-transferase T1 status and gastric cancer risk: a meta-analysis of the literature

To clarify the risk of gastric cancer associated with glutathione S-transferase T1 (GSTT1) status, a meta-analysis of published studies was performed. Eligible studies included all reports investigating an association between GSTT1 status and gastric cancer published before October 31, 2005. A qualitative scoring of papers was applied to evaluate the quality of the published data. The principal outcome measure was the odds ratio (OR) for the risk of gastric cancer associated with GSTT1 deletion status using a random effects model. Eighteen case-control studies detailing a possible association between the GSTT1 null genotype and gastric cancer were selected. Combining data from these studies, totalling 2508 cases and 4634 controls, a non-statistically significant OR for gastric cancer risk associated with GSTT1 deficiency emerged [OR = 1.09; 95% confidence interval (CI): 0.97-1.21; I(2) = 0%]. When only high-quality scored studies were considered, a statistically significant increased risk appeared (OR = 1.23; 95% CI: 1.04-1.45; I(2) = 0%), as well as considering only Caucasians (OR = 1.23; 95% CI: 1.03-1.56; I(2) = 0%). By pooling data from seven studies (319 cases and 656 controls) that considered combinations of GSTT1 and GSTM1 genotypes, a statistically significant increased risk for gastric cancer (OR = 1.95, 95% CI: 1.42-2.67; I(2) = 0%) was detected for individuals with deletion mutations in both genes compared with wild-types. In conclusion, this meta-analysis suggests that the GSTT1 null genotype may slightly increase the risk of gastric cancer and that interaction between unfavourable GST genotypes may exist. Greater attention should, therefore, be paid to the design of future studies; the investigation of interactions among multiple genotypes and environmental exposures are justified to clarify GSTT1 null status influence on gastric cancer risk.     

Genetic polymorphisms of phase II metabolic enzymes and lung cancer susceptibility in a population of Central South China

A case-control study was conducted for analyzing the genetic polymorphisms of phase II metabolic enzymes in 97 patients with lung cancer and 197 healthy subjects from Han ethnic group of Hunan Province located in Central South China. The results showed that the frequencies of glutathione S-transferase (GST) M1-null (GSTM1-) or GSTT1-null (GSTT1-) genotype alone, or combined form of both in lung cancer patients were significantly higher than those of the controls. Genotypes of combining GSTP1 mutant/GSTM1(-) or GSTP1 mutant/GSTT1(-) led to high risk of lung cancer. Individuals carrying any two or all three of GSTM1(-), GSTT1(-) and GSTP1 mutant genotypes have a distinctly increased risk of lung cancer when compared to those with GSTM1 present (GSTM1+: GSTM1+/+ or GSTM1+/-), GSTT1 present (GSTT1+: GSTT1+/+ or GSTT1+/-) and GSTP1 wild genotypes. Furthermore, individuals possessing combined genotypes of N-acetyltransferase 2 (NAT2) rapid acetylator, GSTP1 mutant and both GSTT1(-) and GSTM1(-) have a remarkably higher lung cancer risk than those carrying combined NAT2 slow acetylator genotype, GSTP1 wild genotype and both GSTT1(+) and GSTM1(+) genotypes. All these findings suggest that the genetic polymorphisms of phase II metabolic enzymes affect the susceptibility of lung cancer in the Han ethnic group of Central South China.