UGT1A1基因多态性与伊立替康治疗结直肠癌不良反应的关系

背景与目的：尿苷二磷酸葡萄糖醛酸转移酶1A1(uridine diphosphoglucu-ronosyltransferase 1A1,UGTlA1)是伊立替康代谢关键酶,其活性受基因多态性影响显著。本研究探讨结直肠癌患者中,UGT1A1*28和UGT1A1*6基因多态性与伊立替康治疗相关不良反应之间的关系。方法：入组2013年4月—2013年12月于复旦大学附属中山医院肿瘤内科接受治疗的消化道恶性肿瘤患者160例。抽提外周血中基因组DNA,分别采用STR方法和Sanger测序法,检测UGT1A1*28和UGT1A1*6基因型,分析UGT1A1基因多态性分布情况。对其中82例化疗方案中含伊立替康的结直肠癌患者进行随访,记录不良反应发生情况和严重程度,比较不同基因型患者之间的差异。结果：160例消化道肿瘤患者中,UTG1A1*28(启动子TATA盒区域TA重复次数)野生型TA6/6124例(77.5%);杂合子TA6/7 33例(20.5%);纯合子TA7/7 3例(2.0%)。UGT1A1*6位点(211G>A)野生型GG 105例(65.6%),杂合子GA 48例(30.0%);纯合子AA 7例(4.4%)。82例化疗方案中含伊立替康的结直肠癌患者中,*28基因型(TA6/7和TA7/7)显著增加发生3级以上中性粒细胞减少的风险(58.3% vs 0.0%,P<0.001),并增加整体不良反应发生率(76.0% vs 45.6%,P<0.001);*6基因型(GA和AA)、年龄、性别、化疗方案和伊立替康相关不良反应发生无显著相关性。结论：接受伊立替康化疗的结直肠癌患者,UGT1A1*28位点多态性显著增加中性粒细胞减少发生的风险,可预测伊立替康引起的骨髓抑制性不良反应,辅助临床选择合适的化疗方案。     

UGT1A1*28基因多态性与晚期结直肠癌伊立替康化疗疗效及不良反应的关系

目的:尿苷二磷酸葡糖醛酸转移酶1A1(uridine-diphosphoglucuronosyl transferase 1A1, UGT1A1)作为伊立替康重要的药物代谢酶,其基因多态性可显著影响该酶的活性.本研究旨在观察UGT1A1*28基因多态性与晚期结直肠癌伊立替康化疗疗效和不良反应之间的关系.方法:回顾性研究64例接受伊立替康/氟尿嘧啶一线化疗的晚期结直肠癌患者.从患者外周血白细胞中提取DNA,应用直接测序法检测UGT1A1*28 TATA盒基因序列,并分析基因多态性与化疗不良反应和近期疗效的关系.结果: 51例(79.7%)患者的UGT1A1*28基因启动子区TA序列重复6次,为纯合野生型(TA)6/(TA)6;10例(15.6%)患者的基因型为TA序列重复6次和7次的杂合型(TA)6/(TA)7;3例(4.7%)患者的TA序列重复7次,为纯合突变型(TA)7/(TA)7.UGT1A1*28非野生型的基因多态性可增加患者发生Ⅲ度以上腹泻的风险(38.5% vs 9.8%,P=0.035);UGT1A1*28非野生型基因患者接受伊利替康化疗时,需要下调剂量的比率明显高于野生型基因者(46.2% vs 15.7%,P=0.046).64例患者中28例(43.8%)化疗有效,其中UGT1A1*28野生型基因者22例,非野生型基因者6例,2组的反应率差异无统计学意义(46.2% vs 43.1%,P=0.845).结论:在应用伊立替康化疗的患者中,UGT1A1*28基因启动子区TATA盒基因多态性(TA)6/(TA)7或(TA)7/(TA)7基因型可增加晚期结直肠癌患者接受伊立替康化疗后,发生Ⅲ度以上腹泻的风险,但不影响化疗的近期疗效.     

川东北地区人群结直肠癌患者UGT1A1*28基因多态性与伊立替康所致毒副反应的相关性

目的:观察结直肠癌患者UGT1A1*28基因多态性的分布频率,了解UGT1A1*28基因多态性与结直肠癌患者应用伊立替康联合5-氟尿嘧啶化疗毒副反应的相关性。方法:从384例接受伊立替康联合氟尿嘧啶一线化疗的晚期结直肠癌病例中采外周血提取DNA。采用PCR 法扩增目的基因片段,直接测序法分析UGT1A1*28基因多态性。临床观察并评价患者化疗毒副反应分级,统计分析UGT1A1*28基因表型与化疗毒副反应相关性。结果:全部 384例患者 UGT1A1*28基因多态性分布情况:TA6/6野生基因型287例(74.7％),TA6/7杂合基因型73例（19.0％）,TA7/7纯合基因型24例（6.3％）。化疗毒副反应和UGT1A1*28基因多态性进行临床单因素分析显示UGT1A1*28基因纯合型TA7/7、杂合型TA6/7与3-4度白细胞减少、中性粒细胞减少、腹泻、胆红素升高具有明显相关性（P<0.01）,UGT1A1*28基因纯合型TA7/7及杂合型TA6/7患者发生中性粒细胞减少的风险较UGT1A1*28基因野生型TA6/6患者高5.625倍（OR=5.625）。UGT1A1*28基因纯合型TA7/7和UGT1A1*28基因杂合型TA6/7患者发生腹泻的风险较UGT1A1*28基因野生型TA6/6患者高6.778倍（OR=6.778）。结论:UGT1A1*28基因纯合型TA7/7及杂合型TA6/7患者应用伊立替康化疗后发生重度中性粒细胞减少、重度腹泻的风险高于UGT1A1*28基因野生型TA6/6,为临床伊立替康用药选择、剂量调整、毒副反应的提前干预提供理论依据。     

尿苷二磷酸葡萄糖醛酸转移酶1A1*28基因多态性和伊立替康毒副反应相关性研究

目的初步了解肿瘤患者血中尿苷二磷酸葡萄糖醛酸转移酶1A1(UGT1A1)启动子的多态性分布,并研究其多态性和伊立替康化疗的毒副反应之间的关系。方法收集拟采用伊立替康为基础化疗方案的患者全血标本,直接测序分析UGT1A1~*28 TATA盒基因序列;并与化疗毒副反应进行相关性分析。结果 203例患者进行UGT1A1~*28 TATA基因启动子检测,UGT1A1~*28野生纯合型(TA6/6)最常见,共156例,占76.8%;其次为突变杂合型(TA6/7),共43例,占21.2%;突变纯合型(TA7/7)仅3例,占1.5%;TA5/6有1例,占0.5%。共有183例患者使用含伊立体康方案治疗。突变纯合型(TA7/7)与3度及以上迟发型腹泻和中性粒细胞减少明确相关(P=0.001、P=0.048),与化疗前总胆红素水平升高相关(P0.001);突变杂合型(TA6/7)和野生纯合型(TA6/6)在3度及以上迟发型腹泻和中性粒细胞减少方面的相关性类似(P=0.561、P=0.915),化疗前总胆红素水平类似(P=0.229)。结论 UGT1A1~*28突变纯合型(TA7/7)明显增加伊立替康所致3度及以上延迟性腹泻和中性粒细胞减少,增加化疗前胆红素水平;而UGT1A1~*28突变杂合型(TA6/7)并不增加3、4度迟发型腹泻和粒细胞减少的发生及化疗前总胆红素水平。     

尿苷二磷酸葡萄糖醛酸转移酶1A1~*6和尿苷二磷酸葡萄糖醛酸转移酶~*28基因多态性与伊立替康疗效及不良反应的关系

目的观察尿苷二磷酸葡萄糖醛酸转移酶1A1(UGT1A1*)6和UGT1A1*28基因多态性与伊立替康化疗疗效及不良反应之间的关系。方法采用外周静脉血DNA抽提、聚合酶链反应(PCR)扩增和焦磷酸测序方法分析UGT1A1*6和UGT1A1*8基因型,收集72例2010年1月至2013年12月间接受伊立替康治疗的晚期恶性肿瘤患者的临床资料,观察患者用药期间的药物不良反应及化疗疗效,分析基因多态性与化疗不良反应及近期疗效的关系。结果 72例恶性肿瘤(结直肠癌、小细胞肺癌)患者中,UGT1A1*6野生型G/G 40例(55.6%),杂合突变型G/A 21例(29.2%),纯合突变型A/A 11例(15.2%);UGT1A1*28野生型(TA)6/(TA)651例(70.8%),杂合突变型(TA)6/(TA)720例(27.8%),纯合突变型(TA)7/(TA)71例(1.4%)。UGT1A1*6突变型患者(G/A和A/A)3~4级腹泻和3~4级中性粒细胞减少的发生率分别为65.6%和43.7%,野生型(G/G)分别为30.0%和17.5%,差异均有统计学意义(均P<0.05)。UGT1A1*28突变型患者[(TA)6/(TA)7和(TA)7/(TA)7]3~4级腹泻的发生率(42.9%)高于野生型(17.6%,P<0.05)。各组之间近期化疗疗效差异无统计学意义(P>0.05)。结论 UGT1A1*6突变型患者应用伊立替康化疗发生3级及以上中性粒细胞减少及迟发性腹泻的风险增加,而UGT1A1*28突变型患者发生3级以上迟发性腹泻的风险增加,UGT1A1各基因型之间疗效无明显差异,通过检测UGT1A1基因多态性能够合理选择应用伊立替康。     

UGT1A1基因多态性与伊立替康安全性和有效性的临床研究

  目的  观察57例应用伊立替康治疗进展期消化道肿瘤患者的安全性和有效性。  方法  采用全血基因组DNA提取、PCR法扩增目的基因片段, 直接测序法分析UGT1A1基因多态性, 检测2011年8月至2012年6月在河北医科大学第四医院肿瘤内科住院治疗的57例进展期消化道肿瘤患者应用伊立替康的情况, 观察并记录化疗中出现的不良反应以及疗效。  结果  57例进展期消化道肿瘤患者中, UGT1A1基因启动子区28位点, TA序列6次重复的纯合野生型TA6/6有43例（75.4%）; 基因型为TA序列6次和7次重复的杂合型TA6/7有13例（22.8%）; 基因型为TA序列7次重复的纯合突变型TA7/7有1例（1.8%）。UGT1A1基因启动子区6位点野生型G/G有48例（84.2%）, 杂合突变型G/A有7例（12.3%）, 纯合突变型A/A有2例（3.5%）。在57例采用含伊立替康方案化疗的进展期消化道肿瘤患者中, UGT1A1基因启动子区28位点, TA6/6、TA6/7和TA7/7野生型和突变型发生3级以上中性粒细胞减少者分别为7.0%、14.3%, 发生3级以上腹泻者分别为9.3%、14.3%, 其中纯合突变型仅1例患者, 100%的发生率。UGT1A1基因启动子区6位点, G/G、G/A和A/A野生型和突变型发生3级以上中性粒细胞减少者分别为4.2%、55.6%, 发生3级以上腹泻者分别为12.5%、44.4%, 具有统计学差异。各组之间疗效无统计学差异。  结论  患者UGT1A1*28和UGT1A1*6多态性分布基本一致, UGT1A1*6突变型患者应用伊立替康化疗发生3级以上中性粒细胞减少和腹泻的风险增加, 而UGT1A1*28突变型与以上不良反应并无绝对相关性, UGT1A1各基因型之间疗效无明显差异。能否通过对UGT1A1的筛查, 选择合适患者安全有效的应用伊立替康, 值得临床进一步扩大样本量深入研究。      

UGT1A1基因多态性与伊立替康临床用药安全性及疗效的关系

目的：研究 UGT1A1基因多态性与伊立替康治疗结直肠癌患者的不良反应及疗效之间的关系。方法：自外周血中抽提基因组 DNA,进行 PCR 扩增,应用直接测序法分析2012年3月至2013年3月,于我院行基因检测的65例结直肠癌患者 UGT1A1*28和 UGT1A1*6基因多态性的分布情况。并对这65例应用含伊立替康方案化疗的患者出现的不良反应及化疗疗效,进行观察记录,比较不同基因型间的差异。结果：65例患者中,UGT1A1*28野生型 TA6／6有49例（75．4％）,杂合突变型 TA6／7有14例（21．5％）,纯合突变型TA7／7有2例（3．1％）。UGT1A1*6野生型 G／G 有47例（72．3％）,杂合突变型 G／A 有15例（23．1％）,纯合突变型 A ／A 有3例（4．6％）。在以上65例结直肠癌患者中,UGT1A1基因启动子区28位点,TA6／6、TA6／7和TA7／7型,发生3级以上腹泻者分别为8．2％、37．5％;发生3级以上中性粒细胞减少者分别为28．6％、62．5％。UGT1A1基因启动子区6位点,G／G、G／A 和 A ／A 型,发生3级以上腹泻者分别为12．8％、44．4％;发生3级以上中性粒细胞减少者分别为14．9％、22．2％。各组之间疗效无统计学差异。结论：患者 UGT1A1*28和UGT1A1*6多态性分布基本一致,UGT1A1*28突变型可以使应用含伊立替康化疗患者发生3级以上腹泻和中性粒细胞减少的风险增加。UGT1A1*6突变型可增加3级以上腹泻的发生风险。因此,UGT1A1基因型的检测对伊立替康相关的不良反应有一定的预测作用,可提高用药安全性,在临床用药中起到了指导作用。     

尿苷二磷酸葡醛酰转移酶1A1基因多态性与伊立替康治疗广泛期小细胞肺癌不良反应的相关性

目的 研究尿苷二磷酸葡醛酰转移酶(UGT) 1A1基因多态性与伊立替康方案治疗广泛期小细胞肺癌患者不良反应的关系.方法 采用聚合酶链反应法扩增目的基因片段,直接测序法对UGT1 A1基因多态性进行检测,观察并记录化疗中出现的不良反应及疗效,比较不同基因型患者使用伊立替康不良反应的发生率.结果 58例广泛期小细胞肺癌患者中,UGT1A1* 28野生型45例(77.6％),UGT1 A1 *93野生型40例(69.0％),UGT1A1* 60野生型38例(65.5％),UGT1 A1* 93和UGT1 A1* 60基因突变分别有18例(31.0％)和20例(34.5％).UGT1A1* 28基因型中,TA5突变8例(13.8％),TA7突变5例(8.6％).TA5突变型中≥3级腹泻5例,≥3级白细胞和中性粒细胞减少各3例;UGT1 A1* 93突变型中,≥3级腹泻7例,≥3级白细胞减少6例,≥3级中性粒细胞减少4例.结论 TA5突变型、UGT1A1*93突变型均增加腹泻和≥3级白细胞和中性粒细胞减少的风险,而UGT1 A1(*28、*93、*60)野生型和UGT1 A1* 60突变型未增加药物不良反应的风险.     

UGTIA1基因多态性与IP方案治疗小细胞肺癌毒性和疗效相关性分析

目的：探讨尿苷二磷酸葡萄糖转移酶1A1（UGTIA1）基因多态性与伊立替康联合顺铂（IP方案）治疗广泛期小细胞肺癌的不良反应和疗效相关性。方法：选取中国医学科学院肿瘤医院2009-01-01-2012-12-31初治广泛期小细胞肺癌患者48例,采用伊立替康联合顺铂化疗方案,分析其临床治疗效果和不良反应及其与UGT1A1基因多态性的相关性。结果：48例小细胞肺癌患者IP方案化疗后CR3例,PR32例,SD4侧,PD9例,总有效率为73．0％,疾病控制率为81．3％。主要毒副作用为中性粒细胞减少34例,贫血29例,血小板减少14例,恶心呕吐38例,迟发性腹泻26例,便秘15例,脱发5例,乏力38例,转氨酶升高14例,心电图异常9例。UGT1A1＊28基因多态性的分布为TA6／6野生型基因34例,TA6／7杂合突变型基因11例,TA7／7纯合突变型基因3例;UGT1A1＊6基因多态性的分布为G／C野生型基因33例,A／G杂合突变型基因13例,A／A纯合突变型基因2例。UGT1A1基因多态性与临床疗效无明显相关性,P〉0．05。提示UGT1A1突变型基因可增加患者发生迟发性腹泻的风险,而对中性粒细胞减少无影响。Logistic多因素回归分析结果显示,UGT1A1＊28、UGT1A1＊6、ECOG评分和治疗周期数对迟发性腹泻有明显影响;同时ECOG评分和治疗周期数对中性粒细胞减少存在影响。结论：UGT1A1突变基因对患者迟发性腹泻有明显影响,UGT1A1基因多态性检测可为临床应用伊立替康联合顺铂相关不良反应的预测提供依据,对临床用药安全具有重要意义。     

UGT1A1*28基因多态性与伊立替康疗效和毒副作用相关性研究进展

目的:总结UGT1A1*28基因多态性与伊立替康(CPT-11)疗效及毒性的相关性。方法:应用PubMed及CNKI期刊全文数据库检索系统,以"UGT1A1*28基因多态性、CPT-11、疗效和毒性"为关键词,检索2000-01-2012-05相关文献,共检索到英文文献208篇和中文文献8篇。纳入标准:1)CPT-11的体内代谢;2)UGT1A1*28基因型特点;3)一线化疗;4)UGT1A1*28基因多态性与疗效和毒性的关系。根据纳入标准符合分析的文献28篇。结果:CPT-11的体内代谢与尿苷二磷酸葡萄糖醛酸转移酶家族(UGTS)密切相关,UGTS的表达由UGT1A1基因位点决定。UGT1A1*28为7个TA重复序列,包括纯合型(TA7/TA7)和杂合型(TA6/TA7),随着TA重复序列数目的增加,CPT-11相关毒性增加。多数研究表明,UGT1A1*28基因多态性与CPT-11化疗疗效无关。在欧美人群中,UGT1A1*28与CPT-11的剂量限制性毒性,即延迟性腹泻和中性粒细胞减少有明显相关性;在亚洲人群中,UGT1A1*28与腹泻的关系更为密切。结论:UGT1A1*28基因多态性具有种族差异,今后尚需开展大规模的前瞻性研究来验证UGT1A1*28基因多态性与CPT-11疗效和毒性的关系,从而指导个体化治疗。     

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.