DNA修复基因XPD G312A多态性与肺癌易感性关系的meta分析

背景与目的已有的研究结果显示DNA修复基因XPD G312A多态位点与肺癌发生存在相关性,但研究结果尚未有一致性结论。本研究旨在通过meta分析的方法,综合评价DNA修复基因XPD G312A多态位点与肺癌发病风险的相关性。方法检索PUBMED、EMBASE、清华CNKI全文数据库、万方全文数据库中XPD基因G312A多态位点与肺癌易感性关系的病例对照研究。对符合纳入标准的研究用meta分析的方法进行数据合并,采用RevMan5.0和STATA11.0评价研究间异质性,计算合并OR值及95%CI。并进行敏感性分析和发表偏倚检验。结果共纳入18项研究,累计病例6554例,对照8322例。总体人群中A等位基因及AA基因型携带者肺癌风险明显升高(A vs G:OR=1.06,95%CI:1.00-1.12;AA vs AG+GG:OR=1.20,95%CI:1.06-1.36;AA vs GG:OR=1.19,95%CI:1.04-1.36)。亚洲人群中,AA基因型携带者肺癌风险明显升高(AA vs AG+GG:OR=7.15,95%CI:1.90-26.94;AA vs GG:OR=7.20,95%CI:1.91-27.15)。高加索人群中,AA基因型携带者肺癌风险升高(AA vs AG+GG:OR=1.15,95%CI:1.01-1.31)。结论XPD312A等位基因为肺癌发生的风险等位基因,AA基因型携带者肺癌风险升高,尤其在亚洲人群这种影响更为明显。     

CAV-1基因多态性与散发乳腺癌易感性的相关性分析

[目的]探讨CAV-1基因多态性与散发乳腺癌的相关性。[方法]采用病例对照研究,纳入经病理确诊的135例女性乳腺癌患者作为实验组,166例女性健康体检者为对照组。通过竞争性等位基因特异性PCR法对研究对象基因位点进行分型;采用χ2检验比较CAV-1各SNP基因型及等位基因频率在两组中的分布差异;非条件Logistic回归分析CAV-1基因多态性与乳腺癌易感性的关联。[结果]在共显性模型、显性模型及等位基因模型下rs3807987及rs7804372位点多态性与乳腺癌易感性密切相关。rs3807987:相对于GG基因型,AG、AA基因携带者(AG/AA基因型)均增加乳腺癌的发病风险(P<0.05),OR值分别为2.110(95%CI:1.270~3.505)、1.968(95%CI:1.205~3.216)。rs7804372位点:相对于TT基因型,AT、AA基因携带者(AT/AA基因型)均增加乳腺癌的发病风险(P<0.05),OR值分别为2.088(95%CI:1.285~3.392)、2.059(95%CI:1.293~3.280)。rs12672038位点:在共显性模型、显性模型、等位基因模型均未见rs12672038位点多态性分布与乳腺癌发病风险之间存在相关性。[结论]CAV-1基因rs3807987与rs7804372多态性与乳腺癌易感性相关。     

DNA修复基因XPA单核苷酸多态性与肺癌遗传易感性的研究

目的研究中国汉族人群核苷酸切除修复基因XPA A23G多态与肺癌遗传易感性的关系.方法采用病例-对照研究方法,以PCR-RFLP技术分析了310例经组织学确诊的肺癌病例和341例按年龄、性别频数配对的非肿瘤医院对照XPA基因A23G多态,比较不同基因型与肺癌风险的关系,并探讨不同环境因素在其中所起的影响.结果XPA基因A23G多态三种基因型在肺癌病人和对照间的分布差异具有显著性(x2=6.607,P=0.037).与携带XPA 23AA基因型者相比较,携带至少一个23G等位基因(即23GG和23AG基因型)的个体肺癌风险降低34%(校正OR=0.66,95%CI=0.44～0.98).分层分析显示,此保护作用在肿瘤家族史阳性者中尤为明显,校正OR为0.31(95%CI=0.13～0.76).结论XPA A23G多态性可能与中国汉族人群肺癌遗传易感性有关,这一相关性有待进一步的体内和体外功能学研究来证实.     

RASSF1基因SNP与陕西地区结直肠癌发病风险关系的研究

目的:探讨RASSF1基因第三外显子G133T和第六外显子A315G单核苷酸多态性(SNP)与陕西地区汉族人群结直肠癌(CRC)易感性的关系。方法:采用基于人群的病例对照研究,聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法检测61例CRC和122例健康对照个体RASSF1基因多态位点的基因型频率分布,比较不同基因型与CRC发生风险的关系。结果:RASSF1基因G133T多态的T等位基因频率在CRC患者组为24.6%,显著高于健康对照组的6.1%(P=0.00)。与G/G基因型相比,携带G/T基因型的个体CRC的发病风险显著增加,经性别、年龄、吸烟状况、GIC家族史校正后的OR值为2.33(95%CI=1.05-5.15)。RASSF1基因A315G多态的G等位基因频率在CRC患者组为25.4%,显著高于健康对照组的11.9%(P=0.00)。根据个体吸烟状况进行分层分析发现,与A/A基因型相比,携带A/G基因型和G等位基因(A/G+G/G基因型)可显著增加吸烟个体CRC的发病风险,经性别、年龄、GIC家族史校正后的OR值为4.5(95%CI=1.65-12.28)。根据GIC家族史进行分层分析发现,与A/A基因型相比,携带A/G基因型或G等位基因(A/G+G/G基因型)可显著增加GIC家族史阳性个体CRC的发病风险,经性别、年龄、吸烟状况校正后的OR值为3.78(95%CI=1.39-10.19)。结论:携带RASSF1基因G133T多态的T等位基因(G/T+T/T基因型)可能显著增加陕西地区人群CRC的发病风险。携带RASSF1基因A315G多态的G等位基因(A/G+G/G基因型)可能显著增加陕西地区人群CRC的发病风险。分层分析发现,G等位基因(A/G+G/G基因型)可能显著增加吸烟个体和GIC家族史阳性个体CRC的发病风险。     

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。     

PLCε1基因多态性与食管癌遗传易感性的关联研究

  目的  探讨PLCε1基因rs2274223 A/G单核苷酸多态性(single nucleotide polymorphism,SNP)和rs11599672 T/G SNP与河北省磁县高发区人群食管鳞状细胞癌(esophageal squamous cell carcinoma,ESCC)遗传易感性之间的关系。  方法  采用聚合酶链反应-连接酶检测反应(polymerase chain reaction-ligase detection reaction,PCR-LDR)方法对527例ESCC患者和527例健康对照PLCε1基因rs2274223 A/G SNP和rs11599672 T/G SNP进行基因分型。  结果  ESCC患者组上消化道肿瘤(upper gastrointestinal cancer,UGIC)家族史阳性个体比例为48.6%,显著高于健康对照组(39.3%,χ2=9.25,P=0.002)。ESCC患者组及健康对照组PLCε1基因rs2274223 A/G SNP AA、AG、GG基因型频率分别为48.0%、43.9%、8.1%和57.1%、37.5%、5.4%。与AA基因型相比,携带AG、GG、AG/GG基因型可能增加ESCC的发病风险,经年龄、性别、吸烟状况、UGIC家族史校正后的OR值分别为1.41(95%CI=1.09~ 1.83)、1.71(95%CI=1.03~2.86)、1.45(95%CI=1.13~1.85)。PLCε1基因rs11599672 T/G SNP等位基因频率和基因型频率总体分布在ESCC患者组及健康对照组之间无显著性差异(P>0.05)。应用2LD软件对PLCε1基因rs2274223 A/G SNP和rs11599672 T/G SNP进行联合分析显示,两个多态性位点间不存在连锁不平衡现象(D'=0.11)。与最常见的AT单体型相比,GT单体型增加了ESCC的发病风险(OR=1.36,95%CI=1.08~1.71)。  结论  PLCε1基因rs2274223 A/G SNP可以作为高发区人群ESCC遗传易感性的标志物。UGIC家族史阳性个体、携带PLCε1基因rs2274223 A/G SNP AG、GG基因型的个体罹患ESCC的风险较高,应定期接受食管内镜检查,以便真正实现ESCC的早期诊断、早期治疗。      

GSTM1和CYP2E1基因多态性与肺癌遗传易感性关系的研究

背景与目的肺癌是中国人群恶性肿瘤死因的首位，其发病可能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P4502E1(CYP2E1)基因RsaⅠ／PstⅠ多态性和谷胱甘肽转移酶M1(GSTM1)基因多态性与肺癌易感性之间是否存在相关性。方法应用PCR-RFLP和PCR法检测99例人非小细胞肺癌患者和66例同期住院的肺良性疾病患者CYP2E1基因的RsaⅠ／PstⅠ多态性和GSTM1基因多态性，并分析其与肺癌遗传易感性的相关性。结果(1)CYP2E1基因RsaⅠ／PstⅠ多态性的三种基因型在肺癌组和对照组的频率差异没有统计学意义(χ^2=1．374，P=0．241)。(2)肺癌组GSTM1(-)基因型频率显著高于对照组(分别为57．6％和40．9％)(χ^2=4．401，P=0．036)。(3)携带GSTM1(-)基因型的个体患肺癌的危险性显著高于GSTM1( )基因型的个体(OR=1．96，95％CI=1．042～3．689，P=0．037)。(4)与携带c1／c2或c2／c2基因型的不吸烟个体比较，携带c1／c1基因型的吸烟者患肺癌的风险显著增加(OR=3．525，95％CI=1．168～10．638，P=0．025)。(5)联合分析CYP2E1基因RsaⅠ／PstⅠ多态性和GSTM1基因多态性，携带有c1／c1和GSTM1(-)基因型的个体患肺癌的风险显著高于携带GSTM1( )和c1／c2或c2／c2基因型的个体(OR=3．449，95％CO=1．001～11．886，P=0．050)。按照吸烟因素分层，携带有GSTM1(-)和c1／c1基因型的不吸烟个体患肺癌的风险显著高于携带GSTM1( )和c1／c2或c2／c2基因型的不吸烟个体(OR=11．553，95％CI=1．068-124．944，P=0．044)，携带有GSTM1(-)和c1／c2或c2／c2基因型的不吸烟个体患肺癌的风险同样显著高于携带GSTM1( )和c1／c2或c2／c2基因型的不吸烟个体(OR=13．374，95％CI=1．258～142．166，P=0．032)。结论(1)GSTM1(-)基因型增加人群患肺癌的风险；(2)CYP2E1的c1／c1基因型和GSTM1(-)基因型的联合可增加吸烟和不吸烟人群患肺癌的风险。     

RASSF1基因单核苷酸多态性与食管癌的发病风险

目的:探讨RASSF1基因第三外显子G133T和第六外显子A315G单核苷酸多态性(SNP)与陕西地区汉族人群食管鳞状细胞癌(ESCC)易感性的关系.方法:采用基于人群的病例对照研究,聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法检测120例ESCC和122例健康对照个体RASSF1基因多态位点的基因型频率分布,比较不同基因型与ESCC发生风险的关系.结果:RASSF1基因G133T多态的T等位基因频率和A315G多态的G等基因频率在ESCC患者组分别为17.5%和23.8%,显著高于健康对照组的6.1%和11.9%.根据个体吸烟状况进行分层分析发现,携带G/T基因型或T等位基因(G/T+T/T基因型)和携带A/G基因型或G等位基因(A/G+G/G基因型)可显著增加吸烟个体ESCC的发病风险,经性别、年龄、GIC家族史校正后的OR值分别为11.7和5.02(95%CI=3.95-34.9和2.09-12.06).GIC家族史分层分析发现,携带G/T基因型或T等位基因(G/T+T/T基因型)和A/G基因型可显著增加GIC家族史阳性个体和GIC家族史阴性个体ESCC的发病风险, 经性别、年龄、吸烟状况校正后的OR值为5.08和3.51(95%CI=1.85-13.92和1.69-7.21).结论:携带RASSF1基因G133T多态的T等位基因(G/T+T/T基因型)可能显著增加陕西地区人群ESCC的发病风险.携带RASSF1基因A315G多态的G等位基因(A/G+G/G基因型)可能显著增加陕西地区人群ESCC的发病风险.     

髓过氧化物酶基因-463G/A多态与中国人肺癌遗传易感性

目的 研究髓过氧化物酶（MPO）基因－463G→A单核苷酸多态与肺癌易感性的关系。方法 以PCR－单链构像多态（SSCP）技术,分析了314例肺癌患者和320例正常对照者MPO基因启动子区第－463位核苷酸多态基因型分布,及其与肺癌风险的关系。结果 正常对照组中G和A等位基因频率分别为85.0%和15.0%,而肺癌患者分别为89.0%和11.0%。携带MPO－463GG基因型的个体患肺癌风险比携带GA和AA基因型个体高1.7倍（校正的OR为1.7;95%CI为1.2-2.5）,且此种风险增高只限于肺鳞癌（OR为2.4;95%CI为1.4-3.9）,而与肺腺癌无关（OR为1.3;95%CI为0.8-2.1）。分层分析结果表明,与GA和AA基因型比较,GG基因型并不增加非吸烟者和累积吸烟量＜26包年者患肺癌的风险,但在累积吸烟量≥26包年的吸烟者中,GG基因型发生肺鳞癌的风险比GA和AA基因型高3.3倍。结论 MPO－463 A等位基因显著降低中国人发生吸烟相关性肺鳞癌的风险。     

TSP1基因G1678A和A2210G基因多态性与贲门腺癌发病风险的关联

目的探讨凝血酶敏感蛋白-1(TSP1)基因第10外显子G1678A和第13外显子A2210G单核苷酸多态性（SNP）与中国北方人群贲门腺癌（GCA）遗传易感性的关系。方法采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)分析方法检测145名GCA患者和198名健康对照的TSP1 G1678A和A2210G多态性分布情况。结果TSP1 G1678A多态性位点的基因型及等位基因型频率在贲门腺癌患者组和对照组之间,其总体分布差异均无统计学意义（P>0.05）。根据吸烟状况和上消化道肿瘤家族史分层分析发现,与GG和GA基因型相比,携带AA基因型可能增加非吸烟个体贲门腺癌的发病风险（经性别、年龄和上消化道肿瘤家族史校正后的OR为1.79, 95%CI为1.46~2.11）。TSP1 A2210G位点G等位基因频率在对照组人群中<1%,它可能不是我国北方人群中的常见多态。结论TSP1基因第10外显子AA基因型可能是影响我国北方人群中非吸烟个体贲门腺癌发病风险的因素之一。     

HDAC1-mSin3a-NCOR1, Dnmt3b-HDAC1-Egr1 and Dnmt1-PCNA-UHRF1-G9a regulate the NY-ESO1 gene expression

The NY-ESO1 gene is a cancer/testis antigen considered to be suitable target for the immunotherapy of human malignancies. Despite the identification of the epigenetical silencing of the NY-ESO1 gene in a large variety of tumors, the molecular mechanism involved in this phenomenon is not fully elucidated. In two non epithelial cancers (glioma and mesothelioma), we found that the epigenetic regulation of the NY-ESO1 gene requires the sequential recruitment of the HDAC1-mSin3a-NCOR, Dnmt3b-HDAC1-Egr1 and Dnmt1-PCNA-UHRF1-G9a complexes. Thus, our data illustrate the orchestration of a sequential epigenetic mechanism including the histone deacetylation and methylation, and the DNA methylation processes.     

CYP1A1, SULT1A1, and SULT1E1 polymorphisms are risk factors for endometrial cancer susceptibility

BACKGROUND: In estrogen biosynthetic pathways, many enzymes are important for metabolism, detoxification, and bioavailability. Polymorphisms in these genes may have an effect on the enzymes' function. For example, higher expression and activation of biosynthetic enzymes and lower expression and activation of conjugation enzymes may lead to high toxicity or carcinogenesis. The authors hypothesized that single nucleotide polymorphisms (single nucleotide polymorphisms) of CYP1A1, CYP1A2, CYP1B1, CYP17, SULT1A1, SULT1E1, and SHBG genes may be risk factors for endometrial cancer. METHODS: DNA samples from 150 cases of endometrial cancer and healthy controls (n = 165) were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to determine the genotypic frequency of 13 different polymorphic loci on the CYP1A1 (m1, m2, m3, m4), CYP1A2 1F, CYP1B1 codon432, COMT codon158, CYP17, SULT1A1 (Arg213His, 14A/G, 85C/T in the 3' flanking region), SULT1E1-64G/A promoter region, and SHBG genes. Genotyping was validated by direct DNA sequencing. The authors also investigated the relation between expression of CYP1A1 in endometrial cancer tissues and genotypes of CYP1A1 m1. RESULTS: A decreased frequency of TC + CC genotype of the CYP1A1 m1 (T/C) polymorphism was observed in endometrial cancer patients compared with controls (OR = 0.42; 95% CI, 0.27-0.69). The T-A haplotype of CYP1A1 m1 and m2 was increased in endometrial cancer patients (P = .017). The frequency of CYP1A1 m1 T/C + C/C was higher in a high CYP1A1 expression group (P = .009). The authors also found that individuals carrying the variants of SULT1A1 codon213 and 2 single nucleotide polymorphisms in the 3' flanking region (14A/G and 85C/T) had an increased risk for endometrial cancer. The frequencies of G-A-C and A-G-T haplotypes of these 3 variants were higher in endometrial cancer patients (P < .0001; P = .0002). In addition, the frequency of combined genotypes (SULT1A1 213 GA + AA and CYP1A1 m1 TT) was higher in endometrial cancer patients. (OR, 4.58; 95% CI, 2.35-8.93). CONCLUSIONS: This is the first report on the combined association of CYP1A1 and SULT gene polymorphisms in endometrial cancer that suggests a decreased single nucleotide polymorphism of CYP1A1 and an increased single nucleotide polymorphism for SULT1A1 and SULT1E1 genes may be risk factors for endometrial cancer in Caucasians.     

CYP1A1.

CYP1A1 plays an important role in the metabolism of polycyclic hydrocarbons that occur in the environment and several studies suggest that the genetic polymorphism of the gene may play a role in the predisposition to cancer. In order to evaluate the function of CYP1A1 in vivo as a host factor determinant of environmentally-caused cancers in humans, additional investigations are needed involving not only molecular epidemiological approaches in different ethnic populations but also more direct approaches such as the use of gene-targeted mice as a model system.     

DNA切除修复交叉互补基因1、乳腺癌易感基因、核苷酸还原酶1与非小细胞肺癌

 阐述了近年来非小细胞肺癌（NSCLC）化疗敏感性与DNA 切除修复交叉互补基因1 （ERCC1）、乳腺癌易感基因（BRCA1）、核苷酸还原酶1（RRM1）基因表达关系的研究进展，分析3个基因对NSCLC个体化化疗潜在的指导意义     

Methoxyestrogens exert feedback inhibition on cytochrome P450 1A1 and 1B1

Cytochrome P450 1A1 (CYP1A1) and 1B1 (CYP1B1) catalyze the oxidative metabolism of 17 beta-estradiol (E2) to catechol estrogens (2-OHE2 and 4-OHE2) and estrogen quinones, which may lead to DNA damage. Catechol-O-methyltransferase catalyzes the methylation of catechol estrogens to methoxyestrogens (2-MeOE2, 2-OH-3-MeOE2, and 4-MeOE2), which simultaneously lowers the potential for DNA damage and increases the concentration of 2-MeOE2, an antiproliferative metabolite. In this study, we showed that CYP1A1 and CYP1B1 recognized as substrates both the parent hormone E2 and the methoxyestrogens. Using purified recombinant enzymes, we demonstrated that CYP1A1 and CYP1B1 O-demethylated the methoxyestrogens to catechol estrogens according to Michaelis-Menten kinetics. Both CYP1A1 and CYP1B1 demethylated 2-MeOE2 and 2-OH-3-MeOE2 to 2-OHE2, whereas CYP1B1 additionally demethylated 4-MeOE2 to 4-OHE2. Because the P450-mediated oxidation of E2 and the O-demethylation of methoxyestrogens both yielded identical catechol estrogens as products, we used deuterated E2 (E2-d4), unlabeled methoxyestrogens, and gas chromatography/mass spectrometry to examine both reactions simultaneously. Kinetic analysis revealed that methoxyestrogens acted as noncompetitive inhibitors of E2 oxidation with K(i) ranging from 27 to 153 micro M. For both enzymes, the order of inhibition by methoxyestrogens was 2-OH-3-MeOE2 > or = 2-MeOE2 > 4-MeOE2. Thus, methoxyestrogens exert feedback inhibition on CYP1A1- and CYP1B1-mediated oxidative estrogen metabolism, thereby reducing the potential for estrogen-induced DNA damage.     

Polymorphisms in CYP1B1, GSTM1, GSTT1 and GSTP1, and susceptibility to breast cancer

Polymorphisms in the cytochrome P450 1B1 (CYP1B1) and glutathione S-transferase (GST) drug metabolic enzymes, which are responsible for metabolic activation/detoxification of estrogen and environmental carcinogens, were analyzed for their association with breast cancer risk in 541 cases and 635 controls from a North Carolina population. Each polymorphism, altering the catalytic function of their respective enzymes, was analyzed in Caucasian and African-American women. As reported in previous studies, individual polymorphisms did not significantly impact breast cancer risk in either Caucasian or African-American women. However, African-American women exhibited a trend towards a protective effect when they had at least one CYP1B1 119S allele (OR=0.53; 95% CI=0.20-1.40) and increased risk for those women harboring at least one CYP1B1 432V allele (OR=5.52; 95% CI=0.50-61.37). Stratified analyses demonstrated significant interactions in younger (age < or =60) Caucasian women with the CYP1B1 119SS genotype (OR=3.09; 95% CI=1.22-7.84) and younger African-American women with the GSTT1 null genotype (OR=4.07; 95% CI=1.12-14.80). A notable trend was also found in Caucasian women with a history of smoking and at least one valine allele at GSTP1 114 (OR=2.12; 95% CI=1.02-4.41). In Caucasian women, the combined GSTP1 105IV/VV and CYP1B1 119AA genotypes resulted in a near 2-fold increase in risk (OR=1.96; 95% CI=1.04-3.72) and the three way combination of GSTP1 105IV/VV, CYP1B1 119AS/SS and GSTT1 null genotypes resulted in an almost 4-fold increase in risk (OR=3.97; 95% CI=1.27-12.40). These results suggest the importance of estrogen/carcinogen metabolic enzymes in the etiology of breast cancer, especially in women before the age of 60, as well as preventative measures such as smoking cessation.     

CYP1A1 and GSTM1 polymorphisms affect urinary 1-hydroxypyrene levels after PAH exposure

Certain human biotransformation enzymes have been implicated in the formation and scavenging of the ultimate reactive metabolites, the diolepoxides, from polycyclic aromatic hydrocarbons (PAHs). In the present study, performed on aluminum smelter workers, we have analyzed airborne PAH, the pyrene metabolite 1-hydroxypyrene (1-OHP) in urine, and genotypes for biotransformation enzymes involved in PAH metabolism. The aim was to evaluate the correlation between external exposure and biomarkers of exposure and to investigate to what extent genetic polymorphism in metabolic enzymes can explain interindividual variation in urinary 1-OHP levels. DNA was prepared from blood samples from 98 potroom workers and 55 controls and altogether eight polymorphisms in the CYP1A1, mEH, GSTM1, GSTP1 and GSTT1 genes were analyzed. The 1-OHP excretion was found to correlate significantly (P 100-fold) and univariate and multivariate regression analyses were used to find the variables that could determine differences in excretion. The variation could, to some degree, be explained by differences in exposure to airborne particulate-associated PAHs, the use of personal respiratory protection devices, smoking habits and genetic polymorphisms in the cytochrome P450 1A1, GSTM1 and GSTT1 enzymes. The part of the variance that could be explained by differences in biotransformation genotypes seemed to be of the same order of magnitude as the variance explained by differences in exposure. In the control group as well as in the occupationally exposed group, the highest 1-OHP levels were observed in individuals carrying the CYP1A1 Ile/Val genotype who were also of the GSTM1 null genotype. The results show that urinary 1-OHP is a sensitive indicator of recent human exposure to PAHs and that it may also to some extent reflect the interindividual variation in susceptibility to PAHs.