Toxicology Letters 218 (2013) 194–199 Contents lists available at SciVerse ScienceDirect Toxicology Letters jou rn al h om epa ge: www.elsevier.com/locate/toxlet Investigation of the cumulative body burden of estrogen-3,4-quinone in breast cancer patients and controls using albumin adducts as biomarkers Che Lin a,c , Dar-Ren Chen a , Wei-Chung Hsieh b , Wen-Fa Yu b , Ching-Chiuan Lin c , Mao-Huei Ko c , Chang-Hsin Juan c , Ben-Jei Tsuang c , Po-Hsiung Lin c,∗ a Comprehensive Breast Cancer Center, Changhua Christian Hospital, Changhua, Taiwan b Department of Laboratory Medicine, Da-Chien General Hospital, Miaoli, Taiwan c Department of Environmental Engineering, National Chung Hsing University, Taichung 402, Taiwan h i g h l i g h t s ◮ We compared the body burden of estrogen quinones in Taiwanese women with breast cancer and controls. ◮ Serum E2-3,4-Q was inversely proportional to BMI among premenopausal women. ◮ Elevation of body burden of E2-3,4-Q may play a role in the development of breast cancer. a r t i c l e i n f o Article history: Received 19 November 2012 Received in revised form 5 February 2013 Accepted 8 February 2013 Available online 17 February 2013 Keywords: Protein adducts Estrogen Quinones Biomarker a b s t r a c t Both 17-estradiol-2,3-quinone (E 2 -2,3-Q) and 17-estradiol-3,4-quinone (E 2 -3,4-Q) are reactive metabolites of estrogen. Elevation of E 2 -3,4-Q to E 2 -2,3-Q ratio is thought to be an important indica- tor of estrogen-induced carcinogenesis. Our current study compared the cumulative body burden of these estrogen quinones in serum samples taken from Taiwanese women with breast cancer (n = 152) vs healthy controls (n = 75) by using albumin (Alb) adducts as biomarkers. Results clearly demonstrated the presence of cysteinyl adducts of E 2 -2,3-Q-4-S-Alb and E 2 -3,4-Q-2-S-Alb in all study population at levels ranging from 61.7–1330 to 66.6–1590 pmol/g, respectively. Correlation coefficient between E 2 -2,3-Q-4- S-Alb and E 2 -3,4-Q-2-S-Alb was 0.610 for controls and 0.767 for breast cancer patients (p < 0.001). We also noticed that in premenopausal subjects with body mass index (BMI) less than 27, background levels of E 2 -3,4-Q-2-S-Alb was inversely proportional to BMI with about 25% increase in E 2 -3,4-Q-2-S-Alb per 5 kg/m 2 decrease in BMI (p < 0.001). In addition, we confirmed that mean levels of E 2 -3,4-Q-2-S-Alb in breast cancer patients were ∼5-fold greater than in those of controls (p < 0.001). Overall, this evidence suggests that disparity in estrogen disposition and the subsequent elevation of cumulative body burden of E 2 -3,4-Q may play a role in the development of breast cancer. © 2013 Elsevier Ireland Ltd. All rights reserved. Abbreviations: Alb, albumin; CYP1A1, cytochrome P450 1A1; CYP1B1, cytochrome P450 1B1; E2, 17-estradiol; E2-2,3-Q, 17-estradiol-2,3-quinone; E2-3,4-Q, 17-estradiol-3,4-quinone; E2-2,3-Q-1-S-NAC and E2-2,3-Q-4-S-NAC, reaction products of E2-2,3-Q with N-acetyl-l-cysteine; E2-3,4-Q-2-S-NAC, reaction products of E2-3,4-Q with N-acetyl-l-cysteine; E2-2,3-Q-1-S-Alb and E2-2,3-Q-4- S-Alb, adducts resulting from reaction of E2-2,3-Q with Alb; E2-3,4-Q-2-S-Alb, adducts resulting from reaction of E2-3,4-Q with Alb; E2-2,3-Q-1-S-TFA and E2- 2,3-Q-4-S-TFA, trifluoroacetyl derivative of E2-2,3-Q adduct after adduct cleavage; E2-3,4-Q-2-S-TFA, trifluoroacetyl derivatives of E2-3,4-Q adduct after adduct cleav- age; EI, electron impact; GC–MS, gas chromatograph and mass spectrometer; [ 2 H5]-E2, E2-2,4,16,16,17-d5 ([ 2 H5]-E2); HPLC, high performance liquid chromatog- raphy; MSA, methanesulfonic acid; NAC, N-acetyl-l-cysteine; NCI, negative ion chemical ionization; SD, standard deviation; TFA, trifluoroacetyl; TFAA, trifluo- roacetic acid anhydride. ∗ Corresponding author. Tel.: +886 4 22840441x515; fax: +886 4 22858970. E-mail address: pohsiunglin@yahoo.com (P.-H. Lin). 1. Introduction Considerable evidence indicates that genetic and environmental factors contribute to the risk of developing breast cancer. Mutations in the tumor suppressor genes BRCA1 and BRCA2 confer increased risks for breast cancer (Newman et al., 1988). Polymorphisms in estrogen disposition and DNA repair genes play roles in breast carcinogenesis and have been found to modify breast cancer risk (Okobia et al., 2009; Shin et al., 2007; Hung et al., 2005). Vari- ation in estrogen bioactivation and deactivation genes can also cause imbalance in estrogen metabolism, resulting in accumula- tion of reactive quinone species and increased risk of developing breast cancer (Okobia et al., 2009; Shin et al., 2007). Additionally, increased serum estrogen and modulation of estrogen disposition are both associated with the development of breast cancer (Del Giudice et al., 1998; Yager and Davidson, 2006). Mitogenesis driven 0378-4274/$ – see front matter © 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.toxlet.2013.02.004