肺腺癌患者GSTM1基因型与K-ras突变相关性分析

目的探讨肺腺癌患者谷胱苷肽-S-转移酶μ1（GSTM1）基因型与癌基因K-ras突变的相关关系。方法收集45例肺腺癌患者标本,抽提基因组DNA,PCR扩增GSTM1基因和K-ras基因的第12位密码子,利用PCR法来检测肺癌组织中GSTM1基因型和K-ras基因的突变情况,分析两者之间的相关性。结果在人的肺腺癌组织中,K-ras基因突变率为43．2％,GSTM1基因的缺失率迭52．6％,其中GSTM1基因缺失者与非缺失者的K-ras突变率分别为65．6％和13％,二者之间有显著性差异（P〈0．05）。结论在人肺癌组织中,GSTM1基因的多态性与K-ras基因突变明显相关,这些发现提示GSTM1基因的缺失导致肺腺癌易感性部分是K-ras基因的突变引起。     

RANTES基因多态与2型糖尿病肾病的临床研究

目的探讨RANTES基因启动子G-403A多态与2型糖尿病肾病之间的关系。方法用聚合酶链反应限制性片段长度多态性技术（PCR-RFLP）检测252例RANTES基因启动子G-403A多态的基因型,其中2型糖尿病患者170例（糖尿病非肾病组76例,糖尿病肾病组94例）;正常对照组82例,并对各组间的等位基因频率与基因型频率进行比较。结果糖尿病肾病组的AA基因型频率（24．5％）明显高于正常对照组（14．6％）。糖尿病肾病组的A等位基因频率（52．1％）明显高于正常对照组（40．3％）,差异具有统计学意义（P〈0．05）。结论RANTESG-403A多态与糖尿病肾病的发生有相关性。     

GSTM1和GSTT1基因多态性与抗结核药物性肝损害的关系

目的 探讨汉族人群谷胱甘肽S转移酶M1(GSTMl)和T1(GSTT1)基因多态性与抗结核药物性肝损害(ATDLI)易感性的关系.方法 回顾性分析抗结核治疗后发生肝损害的结核病患者228例(病例组)及未发生肝损害的结核病患者300例(对照组),应用多重PCR技术检测其GSTM1和GSTT1基因多态性.结果 病例组与对照组GSTM1基因缺失型频率分别为58.3％和50.7％,差异无统计学意义(OR=1.363,95％CI=0.963～1.929); GSTT1基因缺失型频率分别为45.2％和49.3％,差异也无统计学意义.联合分析也未发现两种基因在抗结核药物性肝损害发生中具有协同作用.结论 汉族人群GSTM1和GSTT1基因多态性与抗结核药物性肝损害的发生无关.     

GSTT1基因、GSTM1基因多态性与乳腺癌关系的对照研究

目的：探讨女性乳腺癌人群中GSTT1基因、GSTM1基因多态性在乳腺癌发生发展中的作用。为筛选易感人群、早期诊断及有效地预防和治疗措施的建立提供参考依据。方法：采用聚合酶链反应（PCR）、限制性片段长度多态性（RFLP）及琼脂糖凝胶电泳法对105例正常人和100例乳腺癌患者GSTT1基因、GSTM1基因的多态性分布进行检测，Logistic回归等方法估计基因、基因与乳腺癌相关危险因素的交互作用对乳腺癌发病的危险度。结果：GSTT1、GSTM1基因和乳腺癌的危险性呈负相关，OR（95％CI）分别为0．322（0．175～0．593）和0．340（0．188～0．615）；GSTT1基因与GSTM1基因的交互作用和乳腺癌的发病有统计学关联，GSTM1基因和GSTT1基因同时缺失的人群OR（95％CI）为12．338（3．621～22．042）；GSIT1基因及GSTM1基因与多个乳腺癌相关危险因素存在交互作用。结论：GSIT1、GSTM1基因的缺失是乳腺癌发病的危险因素；特定的环境暴露背景下，基因在与环境危险因素的相互作用促进乳腺癌的发生。     

GSTT1基因、GSTM1基因多态性与乳腺癌关系的对照研究

目的：探讨女性乳腺癌人群中GSTT1基因、GSTM1基因多态性在乳腺癌发生发展中的作用。为筛选易感人群、早期诊断及有效地预防和治疗措施的建立提供参考依据。方法：采用聚合酶链反应（PCR）、限制性片段长度多态性（RFLP）及琼脂糖凝胶电泳法对105例正常人和100例乳腺癌患者GSTT1基因、GSTM1基因的多态性分布进行检测，Logistic回归等方法估计基因、基因与乳腺癌相关危险因素的交互作用对乳腺癌发病的危险度。结果：GSTT1、GSTM1基因和乳腺癌的危险性呈负相关，OR（95％CI）分别为0．322（0．175～0．593）和0．340（0．188～0．615）；GSTT1基因与GSTM1基因的交互作用和乳腺癌的发病有统计学关联，GSTM1基因和GSTT1基因同时缺失的人群OR（95％CI）为12．338（3．621～22．042）；GSIT1基因及GSTM1基因与多个乳腺癌相关危险因素存在交互作用。结论：GSIT1、GSTM1基因的缺失是乳腺癌发病的危险因素；特定的环境暴露背景下，基因在与环境危险因素的相互作用促进乳腺癌的发生。     

中国健康汉族和维吾尔族人谷胱甘肽硫转移酶的基因多态性

目的 比较中国健康汉族人和维吾尔族人GSTM1、GSTT1和GSTP1基因多态性分布。方法 用多重PCR分析GSTM1和GSTT1基因多态性，PCR—RFLP检测GSTP15号外显子105位密码子基因多态性。结果 汉族人与维吾尔族人的GSTM1纯合缺失频率接近。分别为56.1％和53.2％。而汉族人的GSTT1纯合缺失频率（50．0％）较维吾尔族人（26．6％）高。汉族人GSTP1 105I／I、I／V和V／V基因型频率分别为60．7％，35．2％和4．1％；维吾尔族人分别为51．3％，40．2％and 8．4％。结论 维吾尔族人与汉族人，除GSTM1外，GSTT1与GSTP1突变基因型频率存在明显种族差异。     

谷胱甘肽硫转移酶M1基因多态与肺癌易感性的关系

目的探讨谷胱甘肽硫转移酶M1（GSTM1）基因多态与支气管肺癌癌变的关系。方法采用回顾性“病例—对照”设计和限制性片段多态检测法（PCR—RFLP）,检测肺癌病例组103例和正常对照组138例的G卯Ml基因多态,以非条件性logistic回归模型分别对年龄、性别进行校正后计算比数比（OR）及95％可信区间（CI）。结果GSTM1的缺陷型基因（D）频率在对照组、肺癌组分别为44.2％和61．2％。logistic回归分析表明．GSTMl缺陷型（D）患肺癌的危险度升高2．09倍,差异有统计学意义。GSTM1（D）可显著增加鳞癌和小细胞癌的患病危险度。结论GSTM1（D）是患肺癌的危险因素,GSTM1（D）存在与吸烟有协同作用。     

脂联素基因多态性与移植后糖尿病的相关性研究

目的：探讨脂联素基因T45G多态性与移植后糖尿病的相关性。方法：398例肾移植术前无糖尿病史的患者,分为移植后糖尿病组（PTDM组,n=97）和非移植后糖尿病组（对照组,n=301）,采用聚合酶链反应-限制性片断长度多态性（PCR—RFLP）技术,对脂联素基因T45G进行基因分型。结果：PTDM组患者GG基因型频率显著高于对照组（13．4％vs．4．6％,P=0．011）,GG基因型患者移植术后发生PTDM的风险分别是TT和TG基因型的2．844和3．289倍（P〈0．01）。结论：脂联素基因T45G的GG基因型是中国肾移植受者发生PTDM的危险因素。     

对氧磷酯酶基因多态性与糖尿病视网膜病变的关系(附236例分析)

目的 探讨对氧磷酯酶2(PON2)基因A148G多态性与糖尿病视网膜病变的关系。方法 (1)用聚合酶链反应—限制性片段长度多态性(PCR—RFLP)分析法探查PON2基因A148G多态性在正常对照组、单纯2型糖尿病组、糖尿病视网膜病变组中的基因分布频率；(2)放免法检测血清免疫反应性胰岛素(IRI)、C肽(C—P)水平。结果 (1)糖尿病视网膜病变组的GG基因型和G等位基因频率明显高于单纯2型糖尿病组(X^2＝3．98 P＜0.05，X^2＝4．49 P＜0.05)和正常对照组(X^2＝8．44 P＜0.01，X^2＝8．66 P＜0.01)；(2)方差分析结果显示基因型为GG的糖尿病患者空腹血糖浓度明显高于基因型为GA和AA的糖尿病患者(F＝3．94 P＜0.05，F＝5．17 P＜0.05)，而正常对照组各基因型间空腹血糖浓度无显著性差异(P＞0.05)；(3)非参数检验表明PON2基因多态性与糖尿病视网膜病变的发生有关(Z＝0．574 P＜0.05)，多因素分析结果表明PON2基因型(相对危险度为3．5471 P＜0．001，模型总判对率90．31％)和空腹血糖浓度(相对危险度为4．0143 P＜0．001，模型总判对率89．74％)与糖尿病视网膜病变独立相关。结论 PON2基因多态性与糖尿病视网膜病变有关，糖尿病视网膜病变的易感性在一定程度上与较高的空腹血糖浓度有关。     

谷胱甘肽S-转移酶M1基因多态性与儿童急性白血病遗传易感性的Meta分析

目的 探讨谷胱甘肽S-转移酶M1（GSTM1）基因多态性与儿童急性白血病（AL）遗传易感性.方法 检索PubMed、Embase、维普中文科技期刊数据库（1999年1月～2013年8月）,收集GSTM1基因多态性与儿童急性白血病相关的病例-对照研究,应用Stata 11.0进行Meta分析,计算合并OR值及95%CI.结果 符合标准的14篇文献纳入Meta分析.数据合并结果显示,GSTM1缺失型的儿童AL病例-对照组有统计学意义,OR值为1.35（95%CI：1.12～1.64,P=0.002）.结论 GSTM1缺失基因型是儿童发生AL的危险因素.     

Polymorphism of GSTM1 and GSTT1 genes in bladder cancer: a study from North India

The present study was conducted (1) to examine whether the GSTT1- and GSTM1-null genotypes are risk factors for bladder cancer, and (2) to study possible association of tobacco usage and age strata with genotype of these patients. This case control study was undertaken over a period of 19 months and included 106 bladder cancer patients and 182 controls; both patients and controls originated from northern part of India. The GSTT1 and GSTM1 genotypes were identified by multiplex PCR in peripheral blood DNA samples. Genotype frequencies among patients and controls were assessed and the association of the genotypes with smoking habits and gender of the patients were statistically determined by the ² test. Frequencies of null genotypes in GSTT1 and GSTM1, were 16% (29/182) and 30% (54/182), respectively, in control individuals. The frequencies of GSTT1- and GSTM1-null genotypes in bladder cancer patients were 26% (28/106) and 40% (42/106), respectively. In conclusion, our study demonstrated that the null genotypes of GSTT1 and GSTM1 were substantially at higher risk for bladder carcinoma compared to the normal healthy controls. The GSTT1- and GSTM1-null genotypes did not show significant association with tobacco usage in bladder cancer patients. However, the null genotypes were statistically significant in female relative to male bladder cancer patients.     

Glutathione S-transferase GSTM1 and GSTT1 null genotypes as potential risk factors for urothelial cancer of the bladder

 Onehundred-and-thirteen patients with cancer of the urinary bladder (cases) were examined with respect to the frequency of null genotypes of the polymorphic glutathione S-transferases GSTM1 and GSTT1. The allelic background in the German population of the area was evaluated by analysing 170 newborns (controls). The frequency of GSTM1 and GSTT1 null genotypes in this population, using methods based upon internal standard controlled polymerase chain reaction (PCR), was 0.54 and 0.18 respectively. An elevated relative bladder cancer risk of GSTM1 null genotype carriers was indicated by comparison of this background with the data of the bladder cancer cases (OR = 1.81; 95% CI [1.10, 2.98]; p = 0.019). The frequencies of the GSTT1 null genotype in the total group of bladder cancer cases versus controls did not differ statistically. However, a significantly higher relative risk of bladder cancer for the GSTT1 null genotype was detected in the cases-subgroup of non-smokers (OR = 3.84; 95% CI [1.21, 12.23]; p = 0.023). Thus, the GSTT1 null genotype might represent a minor risk factor for human bladder cancer which should be further investigated. Received: 2 May 1996 / Accepted: 16 July 1996     

Glutathione<Emphasis Type="Italic"> S</Emphasis>-transferase M1 and T1 null genotype distribution in South Indians

Objective To investigate the distribution of the homozygous null genotypes of GSTM1 and GSTT1 in the South Indian population.Methods Five hundred and seventeen unrelated natives of the South Indian states of Tamilnadu and Pondicherry (n=170), Kerala (n=122), Karnataka (n=110) and Andhra Pradesh (n=115) were analyzed for homozygous deletions of GSTM1 and GSTT1. A multiplex polymerase chain reaction method simultaneously detected both GSTM1 and GSTT1 homozygous null genotypes. The observed frequencies from the four groups were compared statistically with each other and the combined frequencies were compared with frequencies of other major populations previously reported in the literature.Results In South India, 30.4% (95% CI 26.4–34.3) lacked the GSTM1 gene, 16.8% (13.6–20.1) lacked the GSTT1 gene and 4.6% (3.0–6.8) lacked both the GSTM1 and GSTT1 genes. The highest frequency of GSTM1 null was observed in Karnataka (36.4%, 27.4–45.4), while Andhra Pradesh had the lowest frequency of the GSTM1 and GSTT1 combined double-null genotypes (1.7%, 0.21–6.2).Conclusion The prevalence of the GSTM1 null genotype differed within India. The frequency of GSTM1 null in South Indians was significantly lower than that in Caucasians. The frequencies of both GSTM1 and GSTT1 null genotypes in South Indians were significantly lower than in the Japanese.     

Polymorphisms of glutathione S-transferase genes (GSTM1, GSTP1 and GSTT1) and bladder cancer susceptibility in the Turkish population

We investigated the effect of the GSTM1 and GSTT1 null genotypes, and GSTP1 313 A/G polymorphism on bladder cancer susceptibility in a case control study of 121 bladder cancer patients, and 121 age- and sex-matched controls of the Turkish population. The adjusted odds ratio for age, sex, and smoking status is 1.94 [95% confidence intervals (CI) 1.15-3.26] for the GSTM1 null genotype, and 1.75 (95% CT 1.03-2.99) for the GSTP1 313 A/G or G/G genotypes. GSTT1 was shown not to be associated with bladder cancer. Combination of the two high-risk genotypes. GSTM1 null and GSTP1 313 A/G or G/G, revealed that the risk increases to 3.91-fold (95% CI 1.88-8.13) compared with the combination of the low-risk genotypes of these loci. In individuals with the combined risk factors of cigarette smoking and the GSTM1 null genotype, the risk of bladder cancer is 2.81 times (95% CI 1.23-6.35) that of persons who both carry the GSTM1-present genotype and do not smoke. Similarly, the risk is 2.38-fold (95% CI 1.12-4.95) for the combined GSTP1 313 A/G and G/ G genotypes and smoking. These findings support the role for the GSTM1 null and the GSTP1 313 AG or GG genotypes in the development of bladder cancer. Furthermore, gene-gene (GSTM1-GSTP1) and gene-environment (GSTM1-smoking, GSTP1-smoking) interactions increase this risk substantially.     

Polymorphisms of cytochrome P450 1A1, glutathione S-transferases M1 and T1 in a Turkish population

Intra-ethnic as well as inter-ethnic differences are known to exist in the frequencies of cytochrome P450 (CYP) 1A1, glutathione S-transferase (GST) M1, and GSTT1 gene polymorphisms with which associations have been shown for several cancers. In this study, CYP1A1 m2, GSTM1, and GSTT1 gene polymorphisms were determined among 133 healthy individuals of a Turkish population. On the basis of polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) methodology, the frequency of CYP1A1 m2 mutation was determined. The multiplex PCR protocol was used to determine the frequency of the deleted genotypes of both GSTM1 and GSTT1 genes. The frequencies of Ile/Ile (wild type), Ile/Val (heterozygous variant), and Val/Val (homozygous variant) CYP1A1 m2 genotypes were 90.2%, 9.8%, and 0%, respectively. The frequencies of the deleted GSTM1 (null) and GSTT1 (null) genotypes were 51.9% and 17.3%, respectively. These results show that the frequencies of the CYP1A1 m2, GSTM1, and GSTT1 gene polymorphisms in a Turkish population are similar to Caucasian populations.     

Glutathione transferase isozyme genotypes in patients with prostate and bladder carcinoma

Genotype distributions for GSTP1, GSTM1, and GSTT1 were determined in 91 patients with prostatic carcinoma and 135 patients with bladder carcinoma and compared with those in 127 abdominal surgery patients without malignancies. None of the genotypes differed significantly with respect to age or sex among controls or cancer patients. In the group of prostatic carcinoma patients, GSTT1 null allele homozygotes were more prevalent (25% in carcinoma patients vs. 13% in controls, Fisher P =0.02, chi2 P=0.02, OR=2.31, CI = 1.17-4.59) and the combined M1-/T1 -null genotype was also more frequent (9% vs. 3%, chi2 P=0.02, Fisher P = 0.03). Homozygosity for the GSTM1 null allele was more frequent among bladder carcinoma patients (59% in bladder carcinoma patients vs 45% in controls, Fisher P=0.03, chi2 P=0.02, OR=1.76, CI=1.08-2.88). In contrast to a previous report, no significant increase in the frequency of the GSTP1b allele was found in the tumor patients. Except for the combined GSTM1-/ T1-null genotype in prostatic carcinoma, none of the combined genotypes showed a significant association with either of the cancers. These findings suggest that specific single polymorphic GST genes, that is GSTM1 in the case of bladder cancer and GSTT1 in the case of prostatic carcinoma, are most relevant for the development of these urological malignancies among the general population in Central Europe.     

贵州地区汉族人群2型糖尿病肾病RANTES基因启动子多态性分析

目的探讨RANTES基因启动子-28C/G多态性与贵州地区汉族人群2型糖尿病并发肾病之间的关系。方法应用聚合酶链反应限制性片段长度多态性技术(PCR-RFLP),检测143例2型糖尿病患者(53例单纯2型糖尿病患者,90例2型糖尿病合并肾病患者)和55例正常对照组RANTES基因启动子-28C/G基因型,并对各组间的等位基因频率与基因型频率进行检测分析。结果(1)正常对照组与2型糖尿病组相比,-28G阳性基因型频率和G等位基因型频率差异无显著意义(P>0.05)。(2)糖尿病肾病组与单纯糖尿病组相比,-28G阳性基因型频率和G等位基因型频率显著升高(P<0.05)。结论RANTES基因启动子-28G等位基因与贵州地区汉族人群2型糖尿病的发生无关,但可能是糖尿病肾病的易感基因。     

Polymorphism in glutathione S-transferases: susceptibility and treatment outcome for head and neck cancer

The study investigates the association of polymorphism in glutathione S-transferases (GSTs) with susceptibility for head and neck squamous cell carcinoma (HNSCC) and its sites as well as treatment response in cases receiving chemotherapy (CT) and combination of CT-radiotherapy (CT-RT). The case-control study included 500 male cases and an equal number of healthy male controls. Odds ratios (ORs) and 95% confidence intervals (95% CI) were calculated for the association between genotypes and cancer risk. An increase in the risk for HNSCC and cancers of oral cavity, larynx or pharynx was observed in cases with null genotypes of GSTM1 or GSTT1. The interaction of alcohol or tobacco with variant genotypes of GSTM1 or GSTT1 also resulted in a significant increase in the risk for HNSCC. Further, HNSCC cases carrying the null genotypes of GSTM1 and GSTT1 or variant genotypes of GSTP1 showed a significant and superior treatment response. The present data thus provides evidence for the association of polymorphisms in GSTs with risk for HNSCC and its treatment response.     

Glutathione S-transferases mu 1, theta 1, pi 1, alpha 1 and mu 3 genetic polymorphisms and the risk of colorectal and gastric cancers in humans

INTRODUCTION: Glutathione S-transferases (GSTs) are considered to be cancer susceptibility genes as they play a role in the detoxification of carcinogenic species. This study aimed to elucidate the influence of several GST polymorphisms on colorectal and gastric cancer risk. PATIENTS AND METHODS: GST mu1 (GSTM1), theta1 (GSTT1), pi1 (GSTP1), alpha1 (GSTA1) and mu3 (GSTM3) genotypes were determined in 144 colorectal cancer patients, 98 gastric cancer patients and 329 healthy control individuals. RESULTS: Colorectal cancer: the risk is greater for carriers of the GSTM1 null genotype (odds ratio [OR] = 1.91, 95% confidence interval [CI] = 1.25-2.91), for carriers of the GSTT1 null genotype (OR = 3.62, 95% CI = 2.34-5.62), and for simultaneous carriers of both GSTM1 and GSTT1 null genotypes (OR = 4.98, 95% CI = 2.77-9.00). Carriers of the GSTP1 104 Val/Val genotype are at a lower risk (OR = 0.31, 95% CI = 0.09-0.88). Among carriers of the GSTP1 Ile/Ile genotype, smoking increases the risk compared with nonsmoking (OR = 2.35, 95% CI = 1.11-4.99). Gastric cancer: the risk is greater for carriers of the GSTT1 null genotype (OR = 2.58, 95% CI = 1.53-4.36) and for simultaneous carriers of both GSTM1 and GSTT1 null genotypes (OR = 3.32, 95% CI = 1.62-6.77). Carriers of the GSTP1 104 Val/Val genotype are at a lower risk (OR = 0.20, 95% CI = 0.02-0.86). DISCUSSION: The GSTT1 null genotype, particularly if it is associated with the GSTM1 null genotype, greatly increases the risk for colorectal and gastric cancers. The GSTP1 104 Val/Val genotype may protect from both malignant tumors. CONCLUSION: This study indicates that GST polymorphisms, in particular the GSTM1/GSTT1 double-null haplotype, can be considered low-penetrance genes for gastrointestinal cancer.     

Polymorphism in cytochrome P450 CYP2D6, CYP1A1, CYP2E1 and glutathione S-transferase, GSTM1, GSTM3, GSTT1 and susceptibility to tobacco-related cancers: studies in upper aerodigestive tract cancers

Glutathione S-transferase GSTM1, GSTM3 and GSTT1 and cytochrome P450 CYP2D6, CYP1A1 and CYP2E1 loci are susceptibility candidates for cancers of the upper aerodigestive tract because putatively protective and risk genotypes have been identified from studies in other diseases associated with alcohol and tobacco consumption. We describe genotype frequencies in 398 oral, pharyngeal and laryngeal squamous cell carcinoma patients and 219 control individuals. Of the genotypes presumed to be protective, only GSTM1 A/B influenced susceptibility; the GSTM1 A/B frequency was lower in the patients than the control individuals both before [odds ratio = 0.3, 95% confidence interval (CI) 0.1-0.7] and after correction for imbalances in age, sex, smoking and alcohol consumption (odds ratio = 0.2, 95% CI 0.1-0.5). Of the putatively risk genotypes, GSTM3 AA, previously associated with susceptibility to skin cancer, was higher in the cases (odds ratio = 1.6, 95% CI 1.1-2.4). Dividing cases into oral/pharyngeal and laryngeal squamous cell carcinoma showed the GSTM3 AA frequency was higher in laryngeal squamous cell carcinoma than control individuals (odds ratio = 1.6, 95% CI 1.1-2.5) and the difference between control individuals and oral/pharyngeal squamous cell carcinoma approached significance (odds ratio = 1.7, 95% CI 1.0-2.8). The putatively protective GSTM3 BB genotype was lower in patients with glottic (1.0%) than supraglottic (3.0%) squamous cell carcinoma. We identified no differences between patients and control individuals in the frequencies of presumed risk genotypes (e.g. CYP2D6 EM, CYP1A1 m1/m1, CYP1A1 Ile/Ile, CYP2E1 DD, CYP2E1 c1c1, GSTT1 null) or, interactions between genotypes and smoking or alcohol consumption. We conclude, first, that mu class glutathione S-transferase influence risk of upper aerodigestive tract cancers thereby complementing studies in skin cancer patients showing GSTM1 A/B is protective, while GSTM3 AA moderately increases risk. The influence of GSTM1 A/B, but not GSTM1 A or GSTM1 B (mostly heterozygotes with GSTM1*0) suggests that two expressed alleles may attenuate risk. While we found immunohistochemical evidence of GSTM3 expression in the cilia lining the larynx, the biochemical consequences of the polymorphism are unclear. Indeed, the influence of the gene may reflect linkage disequilibrium with another gene. However, we did not find an association with GSTM1 genotypes. Second, we conclude that the CYP2D6, CYP2E1, CYP1A1 and GSTT1 alleles studied, although putatively good candidates, either do not determine the effectiveness of detoxification of tobacco-derived carcinogens in the upper aerodigestive tract or, that chronic consumption of tobacco and alcohol overwhelms enzyme defences, irrespective of genotype.