染色体1p、19q缺失检测在胶质瘤病理诊断中的意义

摘 要：［目的］ 研究染色体1p和19q的缺失在不同病理类型胶质瘤中的分布差异,评价其在胶质瘤病理鉴别诊断中的价值。［方法］ 选取经术后病理确诊的Ⅱ～Ⅲ级胶质瘤患者共134例。采用特异性扩增片段分析法检测肿瘤组织染色体1p、19q缺失情况。［结果］ 134例患者中,组织病理学认定为间变性少突胶质细胞瘤（anaplastic oligodendroglioma,AO,WHO Ⅲ级）9例（6.7%）,少突胶质细胞瘤（oligodendroglial tumor,OT,WHO Ⅱ级）15例（11.2%）,混合型胶质瘤（星形+少突）32例（23.9%）,星型细胞瘤（astrocytoma,AA）78例（58.2%）。少突胶质细胞瘤、间变性少突胶质细胞瘤、混合型胶质瘤、星型细胞瘤的1p、19q缺失率为分别为73.3%（11/15）和 66.7%（10/15）、 66.7%（6/9）和77.8%（7/9）、53.1%（17/32）和59.4%（19/32）、43.6%（34/78）和41.0%（32/78）。染色体1p和19q的缺失情况（包括完整,杂合性缺失,联合缺失）在少突胶质细胞瘤、混合型胶质瘤、星型细胞瘤的分布差异有统计学意义（P<0.05）,但在不同级别少突胶质细胞瘤中,染色体缺失差异无统计学意义。 ［结论］ 染色体1p、19q的缺失与胶质瘤病理类型相关。单纯依靠组织病理学诊断难以准确判断胶质瘤类型,检测染色体1p、19q缺失情况可作为胶质瘤病理诊断的重要参考指标。     

HIF-1α、IGF-1在人脑胶质瘤中的表达及意义

目的探讨HIF-lα蛋白与IGF-1蛋白在人脑胶质瘤中的表达及两者之间的相关性。方法采用免疫组织化学SABC法检测HIF—lα、IGF-1表达蛋白在45例胶质瘤及10例正常脑组织中的表达。结果HIF-lα蛋白在10例正常脑组织中无表达,在45例胶质瘤中28例表达阳性,占62.2%,Ⅰ～Ⅱ级和Ⅲ～Ⅳ级间的表达有显著性差异(P<0.05)。IGF-1蛋白在10例正常脑组织中无表达,在45例胶质瘤中28例表达阳性,占62.2%,Ⅰ—Ⅱ级和Ⅲ—Ⅳ级间表达有显著性差异(P<0.01)。胶质瘤组织HIF-lα蛋白表达与IGF-1蛋白表达密切相关(γs=0.768,P<0.01)。结论HIF-lα蛋白异常表达与胶质瘤的发生有关,而IGF-1可能作为HIF-lα除缺氧以外的另一外诱导因素在HIF-lα促胶质瘤的发生过程中起重要作用。     

CD-DST药敏指导高级别胶质瘤术后辅助化疗的疗效研究

摘 要：［目的］ 探讨胶滴肿瘤药敏检测技术（CD-DST）指导高级别胶质瘤术后辅助化疗的疗效,以及体外敏感性与1p/19q杂合性缺失基因变异相关性。［方法］ 2014年1月至2017年3月确诊高级别脑胶质瘤患者63例,手术肿瘤标本经CD-DST法标准处理后分别对替莫唑胺等5种化疗药物及组合进行检测,根据CD-DST结果指导规范术后辅助化疗方案;FISH探针法测定肿瘤组织1p/19q杂合性缺失基因变异。［结果］ 63例高级别脑胶质瘤患者体外CD-DST检测结果显示替莫唑胺、顺铂、VP-16、卡铂和卡莫司汀的T/C值分别为68.97%、75.43%、68.96%、79.59%和78.14%;联合方案T/C值分别为70.80%、62.23%、72.30%、63.97%和72.13%。CD-DST指导的行规范治疗与未行规范治疗患者的中位总生存期分别为14个月和6个月,差异有统计学意义（P<0.05）。1p/19q杂合性缺失19例（30.2%）,1p/19q杂合性缺失组行规范治疗者中位总生存期显著优于未行规范治疗者（15个月vs 5个月,P<0.001）。［结论］CD-DST指导术后辅助化疗方案显著改善高级别脑胶质瘤的总生存,结合1p/19q杂合性缺失对于胶质瘤的治疗具有预后和治疗预测价值。     

GSTM1和CYP1A1基因多态性与宫颈癌发生及发展的相关性

目的:探讨谷胱苷肽硫转移酶M1（GSTM1）和CYP1A1 Exon7基因多态性与宫颈癌发生发展的关系。方法:选取2013年5月至2015年5月我院收治的宫颈癌患者184例为宫颈癌组,203例进行体检的健康人群为参照组。用限制性片段长度多态性-聚合酶链反应（RFLP-PCR）检测所有受试者GSTM1和CYP1A1 Exon7基因型;记录无进展生存期（PFS）,并随访观察生存和死亡情况。结果:GSTM1分为野生型（wt）和突变缺失型（null）,CYP1A1 Exon7野生型为Ⅱe/Ⅱe,突变型包括突变纯合型（Val/Val）、突变杂合型（Ⅱe/Val）。宫颈癌组携带GSTM1突变型基因型比例与参照组间比较,差异无统计学意义（P＞0.05）;宫颈癌组携带CYP1A1 Exon7突变型基因型比例显著高于参照组（P＜0.05）,且携带突变型基因型个体患宫颈癌的风险是携带野生型基因型个体的2.333倍。GSTM1、CYP1A1 Exon7基因型与宫颈癌患者年龄、病理分期、肿瘤分化程度、肿瘤直径及淋巴结转移均无关（P＞0.05）,与患者病理类型有关（P＜0.05）。GSTM1、CYP1A1 Exon7突变型宫颈癌患者PFS中位数与野生型患者比较,差异均无统计学意义（P＞0.05）。GSTM1、CYP1A1 Exon7突变型宫颈癌患者基因型与宫颈癌患者预后无关（P＞0.05）。结论:GSTM1及CYP1A1 Exon7基因多态性是宫颈癌发生发展的危险因素,尤其是CYP1A1 Exon7突变型,为预防宫颈癌提供依据。     

胶质瘤中FGFR1OP和p57/Kip2蛋白的临床意义

目的:探讨FGFR1OP和p57/Kip2在胶质瘤发生、发展中的作用和临床意义.方法:对中国医科大学附属盛京医院和北京通州区潞河医院的54例胶质瘤手术切除标本,采用SP法进行免疫组织化学染色,检测FGFR1OP和p57/Kip2的表达情况,分析其与胶质瘤临床病理各参数的相关性,并评价其临床意义.结果:FGFR1OP和p57/Kip2在胶质瘤中的阳性表达率分别为66.7%和44.4%,且随着胶质瘤的恶性程度不同表现出显著性差异(P<0.05),FGFR1OP在高度恶性胶质瘤(Ⅲ～Ⅳ级)中的OD值为0.131±0.010,高于在低度恶性胶质瘤(Ⅰ～Ⅱ级)中的OD值(0.118±0.010),两者有显著统计学差异(P=0.000).p57/Kip2在高度恶性胶质瘤(Ⅲ～Ⅳ级)中的OD值(0.156±0.008),低于在低度恶性胶质瘤(Ⅰ～Ⅱ级)中的OD值(0.165±0.006),两者有显著统计学差异(P=0.014).Pearson相关系数检验分析提示FGFR10P和p57/Kip2之间呈负直线相关(r=-0.732,P<0.01).结论:FGFR1OP的高表达与p57/Kip2的低表达可能参与胶质瘤的生长、分化和进展,提示预后不良.     

低级别胶质肿瘤的1p/19q缺失研究

背景与目的：近几年来,少枝胶质细胞瘤,特别是有染色体1p/19q的联合缺失者被证实对烷化剂化疗敏感,成为预后良好的标志物。本实验旨在研究低级别胶质瘤中1p/19q的联合缺失率和与标本中1p/19q的缺失百分比相关的分子病理特征。方法：搜集北京天坛医院低级别胶质瘤标本25例,应用免疫荧光原位杂交（fluorescence in situ hybridization,FISH）的方法对1p36和19q13的缺失程度进行定量分析,统计其在低级别胶质瘤中的联合缺失率,并应用Spearman秩相关分析方法分析标本中1p36、19q13缺失百分比与P170、MGMT、MMP-9、PTEN、EGFR、P53、VEGF、Ki-67、TOPO-Ⅱ、GST-π的分子病理结果的关系。结果：在25例低级别胶质瘤标本中,星形细胞瘤10例,少枝胶质细胞瘤3例,少枝星形细胞瘤12例。在星形细胞瘤、少枝胶质瘤和少枝星形细胞瘤中,1p/19q联合缺失率分别为40%、67%和50%。1p36、19q13的缺失程度与MGMT表达呈负相关,（P分别为0.042和0.015）,1p36的缺失程度与GST-π表达呈负相关（P=0.024）。结论：在低级别胶质瘤中,1p/19q的联合缺失率与国外报道相似,MGMT、GST-π的低表达可能与1p、19q的缺失有关。     

脑胶质瘤组织p14ARF、p53和p21WAF1的表达及其意义

目的:探讨p14ARF、p53和p21WAF1蛋白在不同级别脑胶质瘤组织中的表达及其在胶质瘤发生、发展中的生物学意义.方法:应用免疫组化SP法检测Ⅱ级和Ⅳ级胶质瘤组织中p14ARF、p53和p21WAF1蛋白的表达,并分析其与胶质瘤组织学分级之间的关系.结果:Ⅱ级和Ⅳ级胶质瘤中,p53蛋白的阳性表达率分别为28.00%(7/25)及60.87%(14/23)(P＝0.022),其阳性表达率随胶质瘤恶性程度的增加而升高,Spearman等级相关分析显示,p53的表达与胶质瘤分级呈正相关(P<0.05);p21WAF1的阳性表达率分别为76.00%(19/25)及39.13%(9/23)(P＝0.010) ,p14ARF的阳性表达率分别为76.00%(19/25)及 34.78%(8/23)(P＝0.004),二者阳性表达率均随胶质瘤恶性程度的增加而降低,Spearman等级相关分析显示,p21WAF1、p14ARF的表达与胶质瘤分级呈负相关(P<0.05).结论:胶质瘤组织中,p53呈不同程度的过表达,且随胶质瘤恶性程度的增加而表达水平升高;p21WAF1、p14ARF随胶质瘤恶性程度的增加表达水平降低.突变型p53蛋白的过表达以及p21WAF1、p14ARF蛋白的低表达,可促进胶质瘤的发生、发展.     

利用T1加权动态对比度增强灌注MRI技术确定脑胶质瘤放疗靶区的研究

目的 探讨利用T1加权动态对比度增强灌注MRI (DCEPMRI)技术在放疗中确定脑胶质瘤临床靶区的研究。方法 对 28例脑胶质瘤患者团注顺磁性造影剂Gd-DTPA后,采集其T1加权DCEPMRI,对获得图像用改进的Tofts-Kermode两室分析模型和反卷积法进行处理分析得到微血管通透性相关定量参数K_trans值及图,并比较最大病灶区所在层面常规增强MRI与T1加权DCEPMRI的K_trans值及图,测量各个临床级别脑胶质瘤病灶面积差异。结果 低级别胶质瘤微血管通透性较低、肿瘤浸润范围小,T1加权DCEPMRI与常规增强MRI所测病灶面积误差达 0.2%~0.3%\[Ⅰ、Ⅱ级分别为2.93 cm²∶2.46 cm²(t=6.90,P=0.000)、4.18 cm²∶3.21 cm²(t=10.22,P=0.000)\];高级别胶质瘤微血管通透性较高、肿瘤浸润范围大,T1加权DCEPMRI与常规增强MRI所测量病灶面积误差达 25.1%~26.3%\[Ⅲ、Ⅳ级分别为6.46 cm²∶5.48 cm²(t=10.83,P=0.000)、8.26 cm²∶6.52 cm²(t=18.53,P=0.000)\]。结论 以T1加权DCEPMRI技术得到的微血管通透性相关定量参数K_trans值及彩图为胶质瘤放疗靶区确定提供了更为准确信息,可作为评价肿瘤体积新方法。     

神经胶质瘤nNOS和cGMP表达水平与其病理级别相关关系的研究

目的:分析神经胶质瘤中神经元型一氧化氮合酶(nNOS)和cGMP表达水平与病理级别的相关关系。方法:免疫组化法和Westernblot法测定标本中nNOS的表达水平;放射免疫法测定相同组织中cGMP的表达水平。结果:HE染色显示,36例神经胶质瘤中Ⅰ级为11例,Ⅱ级为14例,Ⅲ级为11例。免疫组化结果显示,在病理级别为Ⅰ、Ⅱ和Ⅲ级的神经胶质瘤中,nNOS的平均光密度值(OD)分别为0·1717±0·0136、0·2744±0·0150和0·3684±0·0150,Ⅰ、Ⅱ级比较及Ⅱ、Ⅲ级比较,差异均有统计学意义,P值均为0·000;神经胶质瘤中nNOS表达水平与其病理级别Ⅰ~Ⅲ级显著正相关,r=0·984,P=0·000,呈Ⅰ<Ⅱ<Ⅲ级。Westernblot结果显示,在病理级别为Ⅰ、Ⅱ和Ⅲ级的神经胶质瘤中,nNOS与β-actin的整合光密度值(IDV)之比分别为1·0900±0·0347、1·2242±0·0292和1·5398±0·0433,Ⅰ、Ⅱ级比较及Ⅱ、Ⅲ级比较,差异均有统计学意义,P值均为0·000;神经胶质瘤中nNOS表达水平与其病理级别Ⅰ~Ⅲ级显著正相关,r=0·953,P=0·000,呈Ⅰ<Ⅱ<Ⅲ级。放射免疫结果显示,在病理级别为Ⅰ、Ⅱ、Ⅲ级的神经胶质瘤中,cGMP的浓度分别为(0·0034±0·0009)、(0·0063±0·0013)和(0·0132±0·0049)pmol/mg,Ⅰ、Ⅱ级比较及Ⅱ、Ⅲ级比较,组间差异均有统计学意义,P值分别为0·017和0·000;神经胶质瘤中cGMP表达水平与其病理级别Ⅰ~Ⅲ级显著正相关,r=0·796,P=0·000,呈Ⅰ<Ⅱ<Ⅲ级。结论:神经胶质瘤中nNOS和cGMP表达水平与其病理级别Ⅰ~Ⅲ级显著正相关,提示利用缓激肽(bradykinin,BK)及其类似物开放血肿瘤屏障的疗效差异可能与两者表达水平有关。     

胶质瘤染色体1p和19q杂合性缺失与O6-甲基鸟嘌呤DNA甲基转移酶p53和Ki-67蛋白表达的关系

目的 探讨胶质瘤染色体1p和19q杂合性缺失(LOH)与O6-甲基鸟嘌呤DNA甲基转移酶(MGMT)、p53和Ki-67蛋白表达的关系.方法 采集146例胶质瘤(45例少突胶质细胞瘤、42例少突星形细胞瘤和59例星形细胞瘤)的肿瘤组织和血液标本,采用聚合酶链反应结合变性高效液相色谱技术检测染色体1p和19q LOH,免疫组化法检测肿瘤组织中MGMT、p53和Ki-67蛋白的表达,并进一步分析其与胶质瘤临床病理特征的关系.结果 少突胶质细胞肿瘤和星形细胞瘤中,1p LOH的发生率分别为59.8％和33.9％,差异有统计学意义(P=0.002);1p和19q LOH的发生率分别为42.5％和16.9％,差异有统计学意义(P=0.001).MGMT低表达和Ki-67高表达多发生于少突胶质细胞肿瘤中,发生率分别为65.5％和54.0％,而p53高表达多发生于星形细胞瘤和少突星形细胞瘤中,发生率为75.2％.在87例少突胶质细胞肿瘤中,1p LOH和MGMT蛋白低表达多发生于Ⅱ级少突胶质细胞肿瘤中,发生率分别为72.5％和87.5％,而p53和Ki-67蛋白高表达多发生于Ⅲ级少突胶质细胞肿瘤中,发生率分别为83.0％和76.6％.1p和19q LOH在非颞叶和颞叶肿瘤的发生率分别为55.6％和21.2％(P=0.002).1p LOH与19q LOH、MGMT蛋白表达与p53蛋白表达、MGMT蛋白表达与Ki-67蛋白表达、1p和19q LOH与p53蛋白表达、1p LOH与Ki-67蛋白表达均有关(均P＜0.05).结论 1p和19q LOH及MGMT、p53和Ki-67的蛋白表达与胶质瘤的临床病理学特征有关,检测其LOH状态和表达水平对胶质瘤的诊断和治疗具有指导作用.     

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.