KiSS-1基因的表达对裸鼠子宫内膜癌皮下种植瘤的影响

目的探讨KiSS-1对子宫内膜癌转移抑制的效果及基因转染的方法和途径。方法将裸鼠分为对照组、空质粒转染组(空质粒与HEC-1B细胞同时注入裸鼠皮下)及KiSS-1质粒转染组(基因质粒与HEC-1B细胞同时注入裸鼠皮下)3组。成瘤后从解剖及组织学角度观察各组皮下瘤及转移瘤的体积和数量变化,从分子生物学水平检测pcDNA3.0-KiSS-1质粒在活体组织中的转染效果及表达水平,分析KiSS-1基因对肿瘤组织细胞侵袭转移能力的影响。结果用子宫内膜癌细胞株建立裸鼠皮下移植瘤是可行的,成瘤率为86%。KiSS-1质粒转染组较对照组及空转染组肿瘤细胞的KiSS-1mRNA表达明显增强,P=0.006。MMP-9mRNA表达明显减弱,P<0.05。实验组中肿瘤细胞KiSS-1mRNA的表达强度与转染pcDNA3.0-KiSS-1质粒的剂量有明确关系,P=0.05。结论建立子宫内膜癌裸鼠皮下种植瘤动物模型方法简单,成功率高,易于观察。KiSS-1基因体内转染方法可行,对细胞生物学影响与转染剂量有明确关系。KiSS-1基因可能是子宫内膜癌基因治疗的一个有前景基因。     

PTEN对子宫内膜癌细胞株迁移和侵袭能力的影响

背景与目的：10号染色体上磷酸酶和张力蛋白同源缺失的基因(phosphatase and tensin homologue deleted on chromosome 10,PTEN)是较为常见的抑癌基因之一。多项研究表明,其在子宫内膜组织中表达量降低,但是对子宫内膜细胞具体的功能及机制却不十分清楚。本研究旨在探讨PTEN对子宫内膜癌HEC-1B细胞迁移及侵袭能力的影响及相关机制,为子宫内膜癌治疗提供新靶点。方法：运用基因重组技术构建pIRES2-ZsGreen1-PTEN重组质粒;将重组质粒转染至子宫内膜癌HEC-1B细胞中,以转染pIRES2-ZsGreen1空载质粒为对照;运用体外划痕、Transwell迁移及侵袭实验分别检测过表达PTEN后细胞迁移和侵袭能力的变化;运用Western blot法检测过表达PTEN后细胞中PTEN、AKT、p-AKT及MMP-2蛋白表达量的变化。结果：PCR产物凝胶电泳显示一条1.2 kb大小的条带,与PTEN cDNA大小符合;基因测序结果与Genbank中PTEN cDNA的序列一致,表明质粒构建成功;转染后48 h荧光显微镜下见荧光且Western blot显示PTEN蛋白表达量增加,表明重组质粒在HEC-1B细胞中表达成功;体外划痕及transwell迁移实验表明,过表达PTEN后HEC-1B细胞的迁移能力减弱;体外侵袭实验显示,过表达PTEN后HEC-1B细胞的侵袭能力明显低于对照组及未处理组;Western blot结果表明,过表达PTEN会降低HEC-1B细胞中p-AKT蛋白表达下降,但是AKT蛋白量却不受影响,同时p-AKT下游的MMP-2蛋白表达量下降。结论：PTEN能明显抑制子宫内膜癌HEC-1B细胞的迁移和侵袭,这一作用可能是通过抑制AKT磷酸化,从而降低MMP-2蛋白的表达而实现的。     

白血病相关基因LRP16真核表达质粒的构建及其在人子宫内膜癌HEC-1-B细胞中的表达

目的:构建白血病相关基因LRP16真核表达质粒,并检测其在人子宫内膜癌HEC-1-B细胞中的表达。方法:从人子宫内膜癌HEC-1-B细胞中提取总RNA,应用PCR技术,扩增获得LRP16基因编码序列片段,克隆入真核表达载体EX-Y2069-M29,对重组质粒进行酶切和测序鉴定后,以脂质体介导法转染至HEC-1-B细胞,采用Western blot法检测LRP16蛋白的表达。结果:酶切和测序结果证明LRP16基因真核表达质粒EX-Y2069-M29的DNA序列完全正确,将其转染HEC-1-B细胞后,LRP16蛋白表达明显增加。结论:LRP16基因重组真核表达质粒EX-Y2069-M29构建成功,并能在HEC-1-B细胞中表达,为进一步研究LRP16基因奠定了基础。     

KiSS-1基因和基质金属蛋白酶-9在妊娠滋养细胞疾病组织中的表达及其意义

目的探讨浸润相关基因KiSS-1和基质金属蛋白酶-9(matrix metalloproteinase,MMP-9)在妊娠滋养细胞疾病中的表达。方法用RT-PCR和Western blot法检测30例正常早期妊娠绒毛、30例葡萄胎、9例侵蚀性葡萄胎和8例绒毛膜癌中KiSS-1和MMP-9mRNA及其蛋白的表达。结果正常妊娠早期绒毛、葡萄胎和侵蚀性葡萄胎组织中均有MMP-9和KiSS-1表达,而在绒毛膜癌组织中仅有MMP-9基因和蛋白的表达,无KiSS-1基因和其蛋白肽metas-tin的表达。妊娠滋养细胞疾病组织[包括葡萄胎、侵蚀性葡萄胎及绒毛膜癌]中MMP-9的基因和蛋白表达均显著高于早期妊娠绒毛组织(P=0·039、0·001、0·000),其中侵蚀性葡萄胎及绒毛膜癌组织中显著高于葡萄胎(P=0·000),绒毛膜癌中MMP-9基因表达水平最高(分别为0·705±0·141和78·403±7·124)。而KiSS-1基因的表达正相反葡萄胎组织的KiSS-1mRNA(0·433±0·193)和metastin表达(23·831±7·522)显著低于早期妊娠绒毛组织(P=0·049、0·049),侵蚀性葡萄胎组织中KiSS-1mRNA和metastin表达水平更低(分别为0·113±0·121和10·814±3·431)。结论促浸润基因MMP-9的表达变化与滋养细胞浸润活性呈正相关,而抑浸润基因KiSS-1的表达变化则与滋养细胞浸润活性呈负相关。这两种基因相互作用在滋养细胞浸润活性调控中起重要作用。     

肿瘤转移抑制基因KAI1对子宫内膜癌细胞增殖、侵袭能力的影响

目的:探讨肿瘤转移抑制基因KAI1基因对子宫内膜癌细胞(AN3CA和HEC-1-B)增殖及侵袭能力的影响。方法:脂质体介导pcDNA3-KAI1质粒转染人子宫内膜癌细胞AN3CA和HEC-1-B,采用免疫印迹法和流式细胞术检测转染前后肿瘤细胞KAI1蛋白的表达,MTT比色法、软琼脂克隆形成实验观察KAI1基因对肿瘤细胞增殖能力的影响,Transwell侵袭实验检测转染前后肿瘤细胞侵袭能力的变化。结果:转染pcDNA3-KAI1质粒后AN3CA和HEC-1-B细胞内和细胞表面均可检测到KAI1蛋白的稳定表达。转染空白质粒组细胞形成克隆数量多体积较大,细胞克隆形成率为(54.2±3.1)%和(52.7±4.3)%,细胞的倍增时间为21.3h和20.1h;基因转染pcDNA3-KAI1质粒组细胞形成克隆数少体积较小,细胞克隆形成率为(37.4±5.1)%和(32.1±3.7)%,细胞的倍增时间为43.7h和45.2h;两组间细胞增殖能力和克隆形成能力比较,差异均有统计学意义(P<0.05)。基因转染组细胞的穿膜细胞数为(91±10.7)/HT、(68±10.8)/HT,而空质粒转染组细胞的穿膜细胞数为(292±11.5)/HT、(219 12.7)/HT,两组细胞比较,侵袭能力亦显著下降(P<0.05)。结论:外源性肿瘤转移抑制基因KAI1有效转染可使子宫内膜癌细胞增殖、侵袭能力均下降,KAI1可能成为子宫内膜癌转移的新治疗靶点。     

过表达miR-125b对子宫内膜癌HEC-1B细胞周期、增殖和凋亡的影响及其可能的机制

探讨miR-125b过表达对子宫内膜癌（endometrial carcinoma, EC）HEC-1B细胞增殖及凋亡的影响及其可能的机制。方法：收集2012年11月至2013年11月间四川省妇幼保健医院收治的30例子宫内膜样腺癌患者肿瘤及其癌旁组织标本,Real-time PCR检测肿瘤组织及培养细胞中miR-125b的表达水平。脂质体转染法分别将miR-125b模拟片段（mimic）与无关序列（scramble mimic）转染入HEC-1B细胞作为miR-125b组和对照组,以野生型HEC-1B细胞为未处理组。流式细胞术和CCK-8法分别检测过表达miR-125b对HEC-1B细胞周期、凋亡和增殖的影响,Western blotting检测过表达miR-125b对HEC-1B细胞中PIK3CD、p-AKT以及总AKT表达的影响。结果：人EC组织中miR-125b表达量较癌旁组织显著下调（P<005）。HEC-1B细胞转染mimic片段后,其miR-125b的表达上调820倍以上。转染48 h后,miR-125b组细胞的增殖能力显著低于对照组和未处理组（0.53±0.06 vs 0.82±0.07、0.89±0.08,P<0.01）、细胞凋亡率显著升高[（21.5±3.2）% vs （142±2.3）%、（13.5±2.1）%,均P＜0.01],并且miR-125b组细胞周期阻滞于G1期;miR-125b组HEC-1B细胞中PIK3CD及其下游p-AKT蛋白表达较对照组和未处理组显著降低（均P<0.01）,而总AKT表达无明显变化（均P＞0.05）。结论：miR-125b在EC组织中普遍低表达,其在HEC-1B细胞中过表达能够明显抑制细胞增殖和周期进程,促进细胞早期凋亡,这可能与miR-125过表达抑制细胞内PI3K/AKT信号通路有关。     

AP-4基因表达下调抑制子宫内膜癌细胞侵袭和迁移能力

目的:观察靶向抑制激活增强子结合蛋白-4(AP-4)基因的表达对子宫内膜癌细胞侵袭和迁移能力的影响。方法:用荧光定量PCR(qRT-PCR)检测人子宫内膜癌细胞株HEC-1A、RL-952、HEC-1B、ishikawa中AP-4基因的表达水平。采用脂质体介导的细胞转染法将AP-4 siRNA转染至HEC-1A细胞,同时设置转染对照。转染48 h后,采用qRT-PCR和蛋白印迹法(Western blot)检测转染后各组HEC-1A细胞中AP-4的表达水平,通过细胞划痕实验观察转染后各组细胞迁移情况,采用Transwell实验检测转染后各组细胞侵袭能力。采用Western blot检测转染后各组细胞中上皮细胞标志分子E-钙粘蛋白(E-cadherin)和间充细胞标志分子N-钙粘素(N-cadherin)、波形蛋白(Vimentin)表达水平。结果:AP-1基因在四株子宫内膜癌细胞中均有表达,在HEC-1A细胞中相对表达水平最高(P<0.05),用于后续转染实验。qRT-PCR和Western blot结果均显示转染AP-4 siRNA能够成功抑制HEC-1A细胞中AP-1 mRNA和蛋白的表达(P<0.05)。Transwell实验显示转染AP-4 siRNA后HEC-1A细胞侵袭能力明显受到抑制(P<0.05)。划痕实验显示转染AP-4 siRNA后HEC-1A细胞迁移能力明显受到抑制(P<0.05)。Western blot结果显示转染AP-4 siRNA后HEC-1A细胞中N-cadherin和Vimentin蛋白水平降低,E-cadherin蛋白水平升高,抑制了上皮间质转化(EMT)过程(P<0.05)。结论:AP-4基因表达下调能够有效抑制子宫内膜癌细胞的侵袭和迁移能力,该过程可能与逆转细胞EMT过程有关。     

子宫内膜癌组织中K-Cl共转运体1的表达及siRNA干扰其表达对子宫内膜癌HEC-1B细胞增殖的影响

目的:探讨K-Cl共转运体1(K-Cl cotransporter 1,KCC 1)mRNA在子宫内膜癌组织中的表达及小干扰RNA(small interfering RNA,siRNA)干扰其表达对子宫内膜癌HEC-1B细胞增殖能力和细胞周期的影响.方法:应用荧光定量PCR的方法检测正常子宫内膜和子宫内膜癌组织中KCC 1 mRNA的表达.设计并合成KCC 1特异性的siRNA,转染子宫内膜癌HEC-1B细胞后,应用RT-PCR、Western印迹法、MTT法和FCM法分别检测HEC-1B细胞中KCC 1 mRNA和蛋白的表达、细胞增殖、细胞周期和细胞凋亡的变化.结果:子宫内膜癌组织中KCC 1 mRNA的表达较正常子宫内膜组织明显增加,差异有统计学意义(P<0.05).KCC 1特异性siRNA能明显抑制HEC-1B细胞中KCC 1 mRNA和蛋白的表达(P<0.05),且HEC-1B细胞的增殖能力明显下降(P<0.05);细胞周期分析显示细胞明显阻滞于G0/G1期,与对照组比较,细胞凋亡增加(P<0.05).结论:KCC 1基因与子宫内膜癌有关,参与细胞周期的调节,具有促进细胞增殖的能力.     

慢病毒介导的LKB1基因在子宫内膜癌HEC-1A细胞中的表达

目的：探讨慢病毒系统介导的LKB1基因在子宫内膜癌HEC-1A细胞中的过表达,为进一步研究LKB1基因在子宫内膜癌的作用机制奠定基础。方法以PCR扩增LKB1克隆质粒获得全长cDNA,将LKB1 cDNA链接到慢病毒载体pWPI,构建慢病毒表达质粒LKB1/pWPI。通过与包装质粒pCMV-Dr8.74和pMD2.G共转染293T细胞进行病毒包装,用包装成功后的病毒液感染子宫内膜癌HEC-1A细胞,以荧光定量PCR、Western blot法检测HEC-1A细胞中LKB1的相对表达量。结果成功扩增LKB1全长cDNA和构建LKB1重组慢病毒表达载体LKB1/pWPI。转染包装293T细胞后能产生慢病毒颗粒并能有效感染靶细胞HEC-1A。转染后HEC-1A-LKB1-pWPI细胞中LKB1的表达率明显高于亲本细胞和空白对照细胞（P〈0.01）。结论成功构建携带LKB1基因的慢病毒表达载体,包装病毒后能有效地感染子宫内膜癌HEC-1A细胞,为进一步探讨LKB1基因在子宫内膜癌中的生物学效应奠定了基础。     

AT1-R在雌激素诱导子宫内膜癌细胞增殖中的作用

目的:探讨血管紧张素受体1(angiotensin Feceptor 1,AT1-R)在雌激素诱导子宫内膜癌细胞HEC-1A增殖、细胞周期转化中的作用及其对细胞外调节蛋白激酶(extracellular signal-regulated kinases 1/2,ERK1/2)表达的影响.方法:免疫荧光技术检测AT1-R在HEC-1A细胞中的表达;脂质体介导AT1-R-siRNA质粒转染人子宫内膜癌细胞HEC-1A,经G418选择培养,采用Westemblot检测转染前后HEC-1A细胞中AT1-R蛋白的表达.MTT法检测无雌激素诱导及雌激素诱导10rmin转染前后细胞的增殖;流式细胞技术检测细胞周期;Western blot检测ERK1/2蛋白及ER蛋白表达水平.结果:转染AT1-R-siRNA-GFP后,与未转染组相比AT1-R蛋白表达降低41.79%(P＜0.01);沉默AT1-R能够抑制17B-E2对HEC-1A细胞的促增殖作用.1713-E2处理10min后,HEC-1A细胞G1期细胞减少,S期细胞增多,细胞增殖明显(P＜0.05);AT1-R沉默后,能够抑制17β-E2诱导的HEC-1A细胞周期转化,使G1期细胞增加,S期细胞减少(P＜0.05);雌激素处理10min后,HEC-1A细胞ERK1/2蛋白表达水平升高,沉默AT1-R后ERK1/2蛋白表达水平又明显降低.17β-E2诱导及AT1-R沉默对HEC-1A细胞ER蛋白表达无明显影响.结论:AT1-R在雌激素诱导子宫内膜癌细胞HEC-1A增殖,细胞周期转化中具有重要作用,其机制可能与ERK1/2表达降低有关,与ER表达无关.     

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.