依據美國政府工業衛生師協會(American Conference of Governmental Industrial Hygienists, ACGIH)對於苯暴露的量測，建議以尿中苯之代謝物2,4-己二烯二酸 (trans,trans-muconic acid, ttMA)和苯基硫醇酸 (S-phenylmercapturic acid, SPMA)為生物暴露指標值 (biological exposure indices, BEIs)，在時量平均容許濃度恕限值 (threshold limit values- time weighted average, TLV-TWA)為0.5 ppm時，其BEI值分別為500和25 μg/g creatinine。根據過去文獻，GST (Glutathione S-transferase)基因型會影響尿中苯代謝物ttMA和SPMA濃度，但是影響的程度是不ㄧ致的，這代表ttMA/SPMA濃度比例也許會受到GST基因多型性的影響。而過去研究也指出CYP2E1 (Cytochrome P450 2E1)基因型似乎會影響此兩種代謝物。
本研究之目的為(1) 探討空氣中苯濃度與尿液中苯代謝物ttMA與SPMA的相關性。(2) 評估苯暴露勞工尿液中ttMA與SPMA的濃度與兩者比例是否會受到CYP2E1和GST之基因多型性的影響。
本研究結果顯示：CYP2E1 Rsa1 & Pst1之基因多型性對於ttMA、SPMA濃度及其ttMA/SPMA濃度比例沒有任何影響。在GST基因多型性方面，尿中苯代謝物SPMA濃度於GSTT1 positive族群會明顯高於deficient族群；另外，GSTT1 positive族群尿中代謝物ttMA/SPMA濃度比例比GSTT1 deficient族群低，推測尿中ttMA的濃度可能也會受到GSTT1的影響。因此，在評估苯暴露族群時，GSTT1之基因型可能為一易感性指標。

Both urinary trans,trans-muconic acid (ttMA) and S-phenylmercapturic acid (SPMA) are currently suggested as biological exposure indices (BEIs) for benzene exposure by American Conference of Governmental Industrial Hygienists (ACGIH). The BEI values of ttMA and SPMA are 500 and 25 μg/g creatinine, respectively, based on the threshold limit values-time weighted average (TLV-TWA) of 0.5 ppm. According to previous studies show the GST (Glutathione S-transferase) genotype polymorphism can influence the excretion of urinary ttMA and SPMA. Nevertheless, these observations are not consistent in these reports of which the GST genotypes influence the levels of benzene metabolites. These results also revealed that the concentration ratio of urinary ttMA level to SPMA level may be influenced by GST genotype polymorphism. In previous report, CYP2E1 (Cytochrome P450 2E1) genotype may affect the metabolism of benzene. Therefore, the purposes of this study are (1) to investigate the correlation of the urinary benzene metabolites, SPMA and ttMA, to the benzene exposure; (2) to investigate whether different genotypes, including CYP2E1 and GST, can affect the ttMA and SPMA levels and ratio of ttMA to SPMA or not. The urinary ttMA, SPMA level and ttMA to SPMA concentration ratio showed no significant difference among subgroups of CYP2E1 Rsa1 & Pst1 genotype polymorphism. In GST genotype polymorphism, the SPMA levels of GSTT1 positive genotype subjects were higher than the GSTT1 deficient genotype subjects. In addition, the ttMA to SPMA concentration ratios of GSTT1 positive subjects were lower than that of GSTT1 deficient subjects. The data represented that the urinary ttMA excretion levels may be influenced by GSTT1. GSTT1 genotype should be considered as factor of susceptibility for assessment of benzene metabolism.

American Conference of Governmental Industrial Hygienists (ACGIH). Benzene. USA. (2001).

American Conference of Governmental Industrial Hygienists (ACGIH).Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices. U.S.A. (2000).

Arias IM, Fleischner G, Kirsch R, Mishkin S, and Gatmaitan Z. In glutathione: Metabolism and function. Raven Press, New York. 20:175-188 (1996).

Avogbe PH, Ayi-Fanou L, Autrup H, Loft S, Fayomi B, Sanni A, Vinzents P, and Møller P. Ultrafine particulate matter and high-level benzene urban air pollution in relation to oxidative DNA damage. Carcinogenesis. 26:613-620 (2005).

Bell DA, Taylor JA, Paulson DF, Robertson CN, Mohler JL, and Lucier GW. Genetic risk and carcinogen exposure: a common defect of the carcinogen-metabolism gene glutathione S-transferase M1 (GSTM1) that increase susceptibility to bladder cancer. Journal of the National Cancer Institute. 85:1159-1164 (1993).

Bergamaschi E, Brustolin A, Palma CD, Manini P, Mozzoni P, Andreoli R, Cavazzini S, and Mutti A. Biomarkers of dose and susceptibility in cyclists exposed to monoaromatic hydrocarbons. Toxicology Letters. 108:241-247 (1999).

Board P, Coggan M, Johnston P, Ross V, Suzuki T, and Webb G. Genetic heterogeneity of the human glutathione transferase: a complex of gene families. Clinical Pharmacology and Therapeutics. 48:357-369 (1990).

Boogaard PJ and van Sittert NJ. Suitability of S-phenyl mercapturic acid and trans, trans-muconic acid as biomarkers for exposure to low concentrations of benzene. Environmental Health Perspectives. 104:1151-1157 (1996).

Boogaard PJ and Van Sittert NJ. Biological monitoring of exposure to benzene: a comparison between S-phenylmercapturic acid, trans,trans-muconic acid, and phenol. Occupational and Environmental Medicine. 52(9):611-620 (1995).

Butkiewicz D, Grzybowska E, Phillips DH, Hemminki K, and Chorazy M. Polymorphisms of the GSTP1 and GSTM1 genes and PAH-DNA adducts in human mononuclear white blood cells. Environmental and Molecular Mutagenesis. 35:99-105 (2000).

Chenevix-Trench G, Young J, Coggan M, and Board P. Glutathione S-transferase M 1 and T1 polymorphisms: susceptibility to colon cancer and age of onset. Carcinogenesis. 16:1655-1657 (1995).

Cheng YJ, Chien YC, Hildesheim A, Hsu MM, Chen IH, Chuang J, Chang J, Ma YD, Luo CT, Hsu WL, Hsu HH, Huang H, Chang JF, Chen CJ, and Yang CS. No association between genetic polymorphisms of CYP2E1, GSTM1, GSTT1, GSTP1, NAT2, and nasopharyngeal carcinoma in Taiwan. Cancer Epidemiology, Biomarkers & Prevention. 12:179-180 (2003).

Dirksen U, Moghadam KA, Mambetova C, Esser C, Führer M, and Burdach S. Glutathione S transferase theta 1 gene (GSTT1) null genotype is associated with an increased risk for acquired aplastic anemia in children. Pediatric Research. 55:466-471 (2004).

Dor F, Dab W, Empereur-Bissonnet P, and Zmirou D. Validity of biomarkers in environmental health studies: the case of PAHs and benzene. Critical Reviews in Toxicology 29:129-68 (1999).

Eaton DL and Bammler TK. Concise review of the glutathione S-transferases and their significance to toxicology. Toxicological Sciences. 49(2):156-164 (1999).

Fustinoni S, Consonni D, Campo L, Buratti M, Colombi A, Pesatori AC, Bonzini M, Bertazzi PA, Foa V, Garte S, Farmer PB, Levy LS, Pala M, Valerio F, Fontana V, Desideri A, and Merlo DF. Monitoring low benzene exposure: comparative evaluation of urinary biomarkers, influence of cigarette smoking, and genetic polymorphisms. Cancer Epidemiology, Biomarkers & Prevention. 14(9):2237-2244 (2005).

Garte S, Gaspari L, Alexandrie AK, Ambrosone C, Autrup H, Autrup JL, Baranova H, Bathum L, Benhamou S, Boffetta P, Bouchardy C, Breskvar K, Brockmoller J, Cascorbi I, Clapper ML, Coutelle C, Daly A, Dell'Omo M, Dolzan V, Dresler CM, Fryer A, Haugen A, Hein DW, Hildesheim A, Hirvonen A, Hsieh LL, Ingelman-Sundberg M, Kalina I, Kang D, Kihara M, Kiyohara C, Kremers P, Lazarus P, Le Marchand L, Lechner MC, van Lieshout EM, London S, Manni JJ, Maugard CM, Morita S, Nazar-Stewart V, Noda K, Oda Y, Parl FF, Pastorelli R, Persson I, Peters WH, Rannug A, Rebbeck T, Risch A, Roelandt L, Romkes M, Ryberg D, Salagovic J, Schoket B, Seidegard J, Shields PG, Sim E, Sinnet D, Strange RC, Stucker I, Sugimura H, To-Figueras J, Vineis P, Yu MC, and Taioli E. Metabolic gene polymorphism frequencies in control populations. Cancer Epidemiology, Biomarkers & Prevention. 10:1239-1248 (2001).

Guengerich FP. Common and uncommon cytochrome P450 reactions related to metabolism and chemical toxicology. Chemical Research in Toxicology. 14:611-650 (2001).

Harada S. [Classification of alcohol metabolizing enzymes and polymorphisms—specificity in Japanese]. Nihon Arukoru Yakubutsu Igkkai Zasshi. 36(2):85-106 (2001).

Hirvonen A, Husgafvel-Pursiainen K, Anttila S, and Vainio H. The GSTM1 Null genotype as a potential risk modifier for squamous cell carcinoma of the lung. Carcinogenesis. 14:1479-1481 (1993).

Hsieh LL, Liou SH, Chiu LL, and Chen YH. Glutathione S-transfrase (GST) M1 and GSTT1 genotypes and hematopoietic effects of benzene exposure. Archives of Toxicology. 73:80-82 (1999).

International Agency for Research on Cancer (IARC). Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Humans. Chemicals, Industrial processes and industries associated with cancer in humans. Supplement7, Lyon, France, (1987).

International Agency for Research on Cancer (IARC). Benzene and Alkylated. Lyon, 81(10):3-68 (1987).

Iucker G. Influence of glutathione S-transferase B (ligandin) on the intermembrane transfer of billrubin. Imphication for the intracellular transport of nonsubstrate ligands in hepatocytes. The Journal of Clinical Investigation. 96:1935-1972 (1995).

Ji X, von Rosenvinge EC, Johnson WW, Tomarev SI, Piatigorsky J, Armstrong RN, and Gilliland GL. Three-dimensional structure, catalytic properties, and evolution of a sigma class glutathione transferase from squid, a progenitor of the lens S-crystallins of cephalopods. Biochemistry. 34(16):5317-5328 (1995).

Junxiang W, Jinxiu S, Lijian H, Dan W, Xipeng J, Naiqing Z, Wei H, Zhaolin X, and Gengxi H. Association of genetic polymorphism in CYP2E1, MPO, NQO1, GSTM1, and GSTT1 genes with benzene poisoning. Environmental Health Perspectives. 110:1213-1218 (2002).

Kato S, Shields PG, Caporaso NE, Hoover RN, Trump BF, Sugimura H, Weston A, and Harris CC. Cytochrome P450IIEI genetic polymorphisms, racial variation, and lung cancer risk. Cancer Research. 52(23):6712-6715 (1992).

Kensler TW, Groopman JD, Sutter TR, Curphey TJ, and Roebuck BD. Development of cancer chemopreventive agents: Oltipraz as a paradigm. Chemical Research in Toxicology. 12(2):113-126 (1999).

Kiffmeyer WR, Langer E, Davies SM, Envall J, Robison LL, and Ross JA. Genetic polymorphisms in the Hmong Population. Cancer. 100:411-417 (2004).

Kim Wj, Kim H, Kim CH, Lee MS, Oh BR, Lee HM, and Katoh T. GSTT1-null genotype is a protective factor against bladder cancer. Urology. 60:913-918 (2002).

Kubota S, Lasker JM, and Lieber CS. Molecular regulation of ethanol-inducible cytochrome P450-IIEI in hamsters. Biochemical and Biophysical Research Communications. 150(1):304-310 (1988).

Lin LC, Chiung YM, Shih JF, Shin TS, Liao PC. Validation of an online dual-loop cleanup device with an electrospray ionization tandem mass spectrometry-based system for simultaneous quantitative analysis of urinary benzene exposure biomarkers trans,trans-muconic acid and S-phenylmercapturic acid. Analytical Chimica Acta. 555:34-40 (2006).

London SJ, Yuan JM, Chung FL, Gao YT, Coetzee GA, Ross RK, and Yu MC. Isothiocyanates, glu-tathione S-transferase M1 and T1 polymorphisms, and lung-cancer risk: a prospective study of men in Shanghai. Lancet. 356:724-729 (2000).

Maugard CM, Charrier J, and Bignon YJ. Allelic deletion at glutathione S-transferase M1 locus and its association with breast cancer susceptibility. Chemico-Biological Interactions. 111-112:365-375 (1998).

Melikian AA, Meng M, O'Connor R, Hu P, and Thompson SM. Determination of the urinary benzene metabolites S-Phenylmercapturic acid and trans,trans-muconic acid by liquid chromatography-tandem mass spectrometry. Carcinogenesis. 120:719-726 (1999).

Melikian AA, Qu Q, Shore R, Li G, Li H, Jin X, Cohen B, Chen LC, Li Y, Yin S, Mu R, Zhang X, and Wang Y. Personal exposure to different levels of benzene and its relationships to the urinary metabolites S-phenylmercapturic acid and trans,trans-muconic acid. Journal of Chromatography. B. 778:211-221 (2002).

Mitrunen K, Jourenkova N, Kataja V, Eskelinen M, Kosma VM, Benhamou S, Vainio H, Uusitupa M, and Hirvonen A. Glutathione S-transferase M1, M3, P1, and T1 genetic polymorphisms and susceptibility to breast cancer. Cancer Epidemiology, Biomarkers & Prevention. 10(3):229-236 (2001).

Nelson D. Cytochrome P450 and the individuality of species. Archives of Biochemistry and Biophysics. 369: 1-10 (1999).

Nomura F, Itoga S, Uchimoto T, Tomonaga T, Nezu M, Shimada H, and Ochiai T. Transcriptional activity of the tandem repeat polymorphism in the 5’-flanking region of the human CYP2E1 gene. Alcoholism. Clinical and Experimental Research. 27(8 Suppl):42S-46S (2003).

Omer B, Ozbek U, Akkose A, and Kilic G. Genetic polymorphism of cytochrome P450 2E1 in the Turkish population. Cell Biochemistry & Function. 19(4):273-275 (2001).

Pavanello S, Gabbani G, Mastrangelo G, Brugnone F, Maccacaro G, and Clonfero E. Influence of GSTM1 genotypes on anti-BPDE-DNA adduct levels in mononuclear white blood cells of humans exposed to PAH. International Archives of Occupational and Environmental Health. 72(4):238-246 (1999).

Popp W, Rauscher D, Muller G, Angerer J, and Norpoth K. Concentrations of benzene in blood and S-phenylmercapturic and t,t-muconic acid in urine in car mechanics. International Archives of Occupational and Environmental Health. 66:1-6 (1994).

Qu Q, Melikian AA, Li G, Shore R, Chen L, Cohen B, Yin S, Kagan MR, Li H, Meng M, Jin X, Winnik W, Li Y, Mu R, and Li K. Validation of biomarkers in humans exposed to benzene: urine metabolites. American Journal of Industrial Medicine. 37:522-531 (2000).

Qu Q, Shore R, Li G, Su L, Jin X, Melikian AA, Roy N, Chen LC, Wirgin I, Cohen B, Yin S, Li Y, and Mu R. Biomarkers of benzene: Urinary metabolites in relation to individual genotype and personal exposure. Chemico-Biological Interactions. 153-154:85-95 (2005).

Ranuio H, Husgafuel PK, Anttila S, Hietanen D, Hirvonen A, and Pelkonen O. Diagnosis of polymorphisms in carcinogen activation and inactivation enzymes and cancer susceptibility. Gene. 159:113-121 (1995).

Rossi AM, Guarnieri C, Rovesti S, Gobba F, Ghittori S, Vivoli G, and Barale R. Genetic polymorphisms influence variability in benzene metabolism in humans. Pharmacogenetics. 9:445-451 (1999).

Saadat I, and Saadat M. Glutathione S-transferase M1 and T1 null genotypes and the risk of gastric and colorectal cancers. Cancer Letters. 169(1):21-26 (2001).

Sandmeyer EE. Aromatic hydrocarbons: benzene. Patty’s Industrial Hygiene and Toxicology. 3rd(2B):3253-3283 (1981).

Sørensen M, Poole J, Autrup H, Muzyka V, Jensen A, Loft S, and Knudsen LE. Benzene exposure assessed by metabolite excretion in Estonian oil shale mineworkers: influence of glutathione S-transferase polymorphisms. Cancer Epidemiology Biomarkers & Prevention. 13:1729-1735 (2004).

Sørensen M, Skov H, Autrup H, Hertel O, and Loft S. Urban benzene exposure and oxidative DNA damage: influence of genetic polymorphisms in metabolism genes. Science of the Total Environment. 309:69-80 (2003).

Stephens EA, Taylor JA, Kaplan N, Yang CH, Hsieh LL, Lucier GW, and Bell DA. Ethnic variation in the CYP2E1 gene: polymorphism analysis of 695 African-Americans, European-Americans and Taiwanese. Pharmacogenetics. 4(4):185-192 (1994).

Tan W, Song N, Wamg G-Q, Liu Q, Tang H-J, F.Kadlubar F, and Lin D-X. Impact of Genetic Polymorphisms in Cytochrome P450 2E1 and Glutathione S-Transferases M1, T1, and P1 on Susceptibility to Esophageal Cancer among High-Risk Individuals in China. Cancer Epidemiology, Biomarkers & Prevention. 9:551-556 (2000).

Verdina A, Crebelli R, Galati R, Falasca G, Ghittori S, and Imbriani M, Tomei F, Marcellini L, Zijno A, and Vecchio VD. Metabolic polymorphisms and urinary biomarkers in subjects with low benezen exposure. Journal of Toxicology & Environmental Health Part A. 64:607-618 (2001).

Wan J, Shi J, Hui L, Wu D, Jin X, Zhao N, Huang W, Xia Z, and Hu G. Association of genetic polymorphisms in CYP2E1, MPO, NQO1, GSTM1, and GSTT1 genes with benzene poisoning. Environmental Health Perspectives. 110:1213-1218 (2002).

Watsons MA, Stewart RK, Smith GB, Massey TE, and Bell DA. Human glutathione S-transferase P1 polymorphisms: relationship to lung tissue enzyme activity and population frequency distribution. Carcinogenesis. 19:275-280 (1998).

Waxman DJ. Glutathione S-transferases: role in alkylating agent resistance and possible target for modulation chemotherapy—a review. Cancer Research. 50(20): 6449-6454 (1990).

Yang BM, O’Reilly DA, Demaine AG,and Kingsnorth AN. Study of polymorphisms in the CYP2E1 gene in patients with alcoholic pancreatitis. Alcohol. 23:91-97 (2001).

Yokoyama A, Kato H, Yokoyama T, Tsujinaka T, Muto M, Omori T, Haneda T, Kumagai Y, Igaki H, Yokoyama M, Watanabe H, Fukuda H, and Yoshimizu H. Genetic polymorphisms of alcohol and aldehyde dehydrogenase and glutathione S-transferase M1 and drinking, smoking, and diet in Japanese men with esophageal squamous cell carcinoma. Carcinogenesis. 23:1851-1859 (2002).

Zhong S, Howie AF, Ketterer B, Taylor J, Hayes JD, Beckett GJ, Wathen CG, Wolf CR, and Spurr NK. Glutathione S-transferase mu locus: use of genotyping and phenotyping assays to assess association with lung cancer susceptibility. Carcinogenesis. 12:1533-1537 (1991).

Zhong S, Wyllie AH, Barnes D, Wolf CR, and Spurr NK. Relationship between the GSTM1 genetic polymorphism and susceptibility to bladder, breast and colon cancer. Carcinogenesis. 14:1821-1824 (1993).

許麗秋、郭錦堂 。 尿中BTEX與其代謝產物關係之研究。 中國醫藥學院環境醫學研究所碩士論文，IEH-1005，p.8-9, 2000。

郭錦堂。利用HPLC和Jaffe測定尿中creatinine之研究，勞工安全衛生研究所季刊，1 (1):75-82, 1993 。

工研院工安衛中心，物質安全資料表 (Material Safety Data Sheet, MSDS)