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Regina G. Ziegler - One of the best experts on this subject based on the ideXlab platform.
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comparison of liquid chromatography tandem mass spectrometry ria and elisa methods for measurement of urinary estrogens
Cancer Epidemiology Biomarkers & Prevention, 2010Co-Authors: Jessica M Faupelbadger, Roni T Falk, Timothy D Veenstra, Larry K Keefer, Barbara J Fuhrman, Robert N Hoover, Regina G. ZieglerAbstract:Absolute and relative concentrations of estrogens and estrogen metabolites are important for clinical decisions as well as for epidemiologic, experimental, and clinical research on hormonal carcinogenesis. RIA and ELISA are routinely used for measuring estrogen metabolites in blood and urine due to efficiency and low cost. Here, we compare absolute and ranked concentrations of estrone, estradiol, and estriol measured by indirect RIA and of 2-Hydroxyestrone and 16alpha-Hydroxyestrone measured by ELISA to the concentrations obtained using a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, which measures 15 estrogen metabolites concurrently. We used overnight urine samples collected from control women (362 premenopausal and 168 postmenopausal) participating in a population-based case-control study of breast cancer among Asian American women ages 20 to 55 years. When comparing RIA or ELISA levels to LC-MS/MS, absolute concentrations for the five estrogen metabolites ranged from 1.6 to 2.9 and 1.4 to 11.8 times higher in premenopausal and postmenopausal women, respectively (all P or =99.6%) and lower coefficients of variation ( or =97.2% and or =95.2% and < or =17.8%). Comparison with the LC-MS/MS method suggests that the widely used RIA and ELISA estrogen metabolite measures may be problematic, especially at low estrogen metabolite levels characteristic of postmenopausal women.
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measuring fifteen endogenous estrogens simultaneously in human urine by high performance liquid chromatography mass spectrometry
Analytical Chemistry, 2004Co-Authors: Timothy D Veenstra, Roni T Falk, Stephen D Fox, John M Roman, Haleem J Issaq, Joseph E Saavedra, Larry K Keefer, Regina G. ZieglerAbstract:A sensitive, specific, accurate, and precise high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry method for measuring the absolute quantities of 15 endogenous estrogens and their metabolites in human urine has been developed and validated. The method requires a single hydrolysis/extraction/derivatization step and only 0.5 mL of urine, yet is capable of simultaneously quantifying estrone and its 2-, 4-methoxy and 2-, 4-, and 16α-hydroxy derivatives, and 2-Hydroxyestrone-3-methyl ether; estradiol and its 2-, 4-methoxy and 2-, 16α-hydroxy derivatives, 16-epiestriol, 17-epiestriol, and 16-ketoestradiol in pre- and postmenopausal women as well as men. Standard curves are linear over a 103-fold concentration range with the standard error of the estimate (SEE) and the relative standard error of the estimate (RSEE) for the linear regression line ranging from 0.0131 to 0.1760 and 1.2 to 7.3%, respectively. The lower limit of quantitation for each estrogen is 0.02 ng/0.5 mL urine...
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a new elisa kit for measuring urinary 2 Hydroxyestrone 16α Hydroxyestrone and their ratio reproducibility validity and assay performance after freeze thaw cycling and preservation by boric acid
Cancer Epidemiology Biomarkers & Prevention, 2000Co-Authors: Roni T Falk, S C Rossi, Thomas R. Fears, H L Bradlow, Herman Adlercreutz, D Sepkovic, Jennifer L. Donaldson, A Migella, Regina G. ZieglerAbstract:There is considerable controversy regarding the role of estrogen metabolites in breast cancer risk, fueled in part by the development of a rapid ELISA that is suitable for large scale investigations. An earlier version of the ELISA could detect values of the 2-Hydroxyestrone (2-OHE1) and 16α-Hydroxyestrone (16α-OHE1) metabolites as low as 2 ng/ml and produce consistent results in premenopausal urines. However, reproducibility was problematic in postmenopausal urines where concentrations of these compounds are much lower. In response to our concern, a new ELISA was developed with a sensitivity of 0.625 ng/ml, which we evaluated using the same pre- and postmenopausal urine samples analyzed in the earlier ELISA. In this report, we present findings on the new kit with regard to reproducibility of the 2-OHE1 and 16α-OHE1 measurements, comparability of results with gas chromatography-mass spectroscopy values, and with regard to the stability of the metabolites after repeated freeze-thaw cycles and after preservation by boric acid. For the most part, we found the new ELISA to be reproducible, with assay coefficients of variation ranging from 10 to 20%, and intraclass correlation coefficients (ICCs) ranging from 80 to 95% in both the pre- and postmenopausal urines. ELISA results for 16α-OHE1 differed from 1 day ( i.e., batch) to the next, and the absolute values of the metabolites obtained by the ELISA were consistently lower than but well correlated with those obtained by gas chromatography-mass spectroscopy. Values of the 2-OHE1:16α-OHE1 ratio also differed between the methods, but because the range of values was not large, the magnitude of these differences was not as great. For the ratio, the correlation between methods was excellent, and the ICCs were high for both groups of women. After preservation by boric acid, values of the ratio varied according to acid concentration but not in a linear fashion. Ratio values were similar in urine samples exposed to four different freeze-thaw cycle treatments, although values for all treatments were consistently lower in one batch. Because batch-to-batch variability was not negligible, it is advisable that matched cases and controls be analyzed in the same batch. Provided this is done, the relatively low assay coefficient of variation and high ICC demonstrate that the new ELISA kit can reliably measure the 2-OHE1:16α-OHE1 ratio and detect small case-control differences in large population-based studies, where rapid and relatively easy laboratory methods are critical.
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Quantifying estrogen metabolism: an evaluation of the reproducibility and validity of enzyme immunoassays for 2-Hydroxyestrone and 16alpha-Hydroxyestrone in urine.
Environmental Health Perspectives, 1997Co-Authors: Regina G. Ziegler, S C Rossi, Thomas R. Fears, H L Bradlow, Herman Adlercreutz, D Sepkovic, P Kiuru, K Wahala, Jimmie B. Vaught, Jennifer L. DonaldsonAbstract:Rapid and simple enzyme immunoassays (EIAs) were recently developed to measure 2-Hydroxyestrone and 16alpha-Hydroxyestrone in unextracted urine. The balance between these competing estrogen metabol...
D Sepkovic - One of the best experts on this subject based on the ideXlab platform.
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Urinary Estrogen Metabolites and Mammographic Parenchymal Patterns
2016Co-Authors: In Postmenopausal Women, Leon H Bradlow, D Sepkovic, Elena Riza, Isabel Dos Santos Silva, Bianca De Stavola, Dimitrios Linos, Athena LinosAbstract:It has been hypothesized that women who metabolize their endogenous estrogens predominantly via 16a-hydroxylation rather than via 2-hydroxylation and, as a result, have a low ratio of 2-Hydroxyestrone (2-OHE1): 16a-Hydroxyestrone (16a-OHE1) are at an increased risk of breast cancer. Epidemiological evidence in support of this hypothesis is scarce and mostly based on measurements made after the onset of the disease. To gain insight into the role of these metabolites in the etiology of breast cancer, we assessed their relationship with high-density Wolfe mammographic parenchymal patterns (P2/DY), a recognized indicator of risk of this tumor. The study was nested within a large cross-sectional survey on determinants of mammographi
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Estrogen Metabolism and Risk of Breast Cancer: A Prospective Study of the 2:16�-Hydroxyestrone Ratio in Premenopausal and Postmenopausal Women
2013Co-Authors: Paola Muti, Leon H Bradlow, D Sepkovic, Andrea Micheli, Vittorio Krogh, Jo L. Freudenheim, Holger J. Schünemann, Martin Stanulla, Jun Yang, Maurizio TrevisanAbstract:Experimental and clinical evidence suggests that 16�-hydroxylated estrogen metabolites, biologically strong estrogens, are associated with breast cancer risk, while 2-hydroxylated metabolites, with lower estrogenic activity, are weakly related to this disease. This study analyzes the association of breast cancer risk with estrogen metabolism, expressed as the ratio of 2-Hydroxyestrone to 16�-Hydroxyestrone, in a prospective nested case-control study. Between 1987 and 1992, 10,786 women (ages 35–69 years) were recruited to a prospective study on breast cancer in Italy, the “Hormones and Diet in the Etiology of Breast Cancer ” (ORDET) study. Women with a history of cancer and women on hormone therapy were excluded at baseline. At recruitment, overnight urine was collected from all participants and stored at �80°C. After an average of 5.5 years of follow-up, 144 breast cancer cases and four matche
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Predictors of the plasma ratio of 2-Hydroxyestrone to 16alpha-Hydroxyestrone among pre-menopausal, nulliparous women from four ethnic groups.
Carcinogenesis, 2003Co-Authors: Helena Jernström, H L Bradlow, D Sepkovic, Thomas L. Klug, Steven A. NarodAbstract:Studies of circulating estrogen levels in relation to pre-menopausal breast cancer risk have yielded inconsistent results. Various estrogen metabolites might affect the risk differently. Estradiol metabolism occurs primarily via two mutually exclusive pathways, yielding 2-Hydroxyestrone (2-OHE) and 16alpha-Hydroxyestrone (16alpha-OHE). Most, but not all, studies have found that a relatively high 2-OHE/16alpha-OHE ratio is associated with a low breast cancer risk. Our objective was to determine if the 2-OHE/16alpha-OHE ratio in plasma correlates with suspected breast cancer risk factors and other lifestyle factors, such as ethnicity, body size, age at menarche, oral contraceptive use, smoking, vegetarian diet, coffee and alcohol consumption in 513 nulliparous women, aged 17-35. Oral contraceptive users had significantly lower 2-OHE/16alpha-OHE ratios than pill non-users (P = 10(-21)). Among women who were not using oral contraceptives, the median 2-OHE/16alpha-OHE ratio in plasma was similar for white, black, Indian/Pakistani and Asian women, after adjustment for age and menstrual cycle phase. Among oral contraceptive users, Asian women had significantly lower 2-OHE/16alpha-OHE ratios than white women, and this result remained after adjustment for age and day of menstrual cycle. Daily coffee consumption was significantly positively correlated with 2-OHE/16alpha-OHE ratios (r(s) = 0.18, P = 0.002) only among pill non-users. Our findings suggest that the plasma 2-OHE/16alpha-OHE ratio is associated with constitutional factors and with modifiable lifestyle factors. The reported elevated risk of early onset breast cancer among young oral contraceptive users could be mediated in part through altered estrogen metabolism induced by synthetic estrogens and progestins.
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Estrogen Metabolism and Risk of Breast Cancer: A Prospective Study of the 2:16α-Hydroxyestrone Ratio in Premenopausal and Postmenopausal Women
Epidemiology (Cambridge Mass.), 2000Co-Authors: Paola Muti, H L Bradlow, D Sepkovic, Andrea Micheli, Vittorio Krogh, Jo L. Freudenheim, Holger J. Schünemann, Martin Stanulla, Jun Yang, Maurizio TrevisanAbstract:Experimental and clinical evidence suggests that 16alpha-hydroxylated estrogen metabolites, biologically strong estrogens, are associated with breast cancer risk, while 2-hydroxylated metabolites, with lower estrogenic activity, are weakly related to this disease. This study analyzes the association of breast cancer risk with estrogen metabolism, expressed as the ratio of 2-Hydroxyestrone to 16alpha-Hydroxyestrone, in a prospective nested case-control study. Between 1987 and 1992, 10,786 women (ages 35-69 years) were recruited to a prospective study on breast cancer in Italy, the "Hormones and Diet in the Etiology of Breast Cancer" (ORDET) study. Women with a history of cancer and women on hormone therapy were excluded at baseline. At recruitment, overnight urine was collected from all participants and stored at -80 degrees C. After an average of 5.5 years of follow-up, 144 breast cancer cases and four matched controls for each case were identified among the participants of the cohort. Among premenopausal women, a higher ratio of 2-Hydroxyestrone to 16alpha-Hydroxyestrone at baseline was associated with a reduced risk of breast cancer: women in the highest quintile of the ratio had an adjusted odds ratio (OR) for breast cancer of 0.58 [95% confidence interval (CI) = 0.25-1.34]. The corresponding adjusted OR in postmenopausal women was 1.29 (95% CI = 0.53-3.10). Results of this prospective study support the hypothesis that the estrogen metabolism pathway favoring 2-hydroxylation over 16alpha-hydroxylation is associated with a reduced risk of invasive breast cancer risk in premenopausal women.
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a new elisa kit for measuring urinary 2 Hydroxyestrone 16α Hydroxyestrone and their ratio reproducibility validity and assay performance after freeze thaw cycling and preservation by boric acid
Cancer Epidemiology Biomarkers & Prevention, 2000Co-Authors: Roni T Falk, S C Rossi, Thomas R. Fears, H L Bradlow, Herman Adlercreutz, D Sepkovic, Jennifer L. Donaldson, A Migella, Regina G. ZieglerAbstract:There is considerable controversy regarding the role of estrogen metabolites in breast cancer risk, fueled in part by the development of a rapid ELISA that is suitable for large scale investigations. An earlier version of the ELISA could detect values of the 2-Hydroxyestrone (2-OHE1) and 16α-Hydroxyestrone (16α-OHE1) metabolites as low as 2 ng/ml and produce consistent results in premenopausal urines. However, reproducibility was problematic in postmenopausal urines where concentrations of these compounds are much lower. In response to our concern, a new ELISA was developed with a sensitivity of 0.625 ng/ml, which we evaluated using the same pre- and postmenopausal urine samples analyzed in the earlier ELISA. In this report, we present findings on the new kit with regard to reproducibility of the 2-OHE1 and 16α-OHE1 measurements, comparability of results with gas chromatography-mass spectroscopy values, and with regard to the stability of the metabolites after repeated freeze-thaw cycles and after preservation by boric acid. For the most part, we found the new ELISA to be reproducible, with assay coefficients of variation ranging from 10 to 20%, and intraclass correlation coefficients (ICCs) ranging from 80 to 95% in both the pre- and postmenopausal urines. ELISA results for 16α-OHE1 differed from 1 day ( i.e., batch) to the next, and the absolute values of the metabolites obtained by the ELISA were consistently lower than but well correlated with those obtained by gas chromatography-mass spectroscopy. Values of the 2-OHE1:16α-OHE1 ratio also differed between the methods, but because the range of values was not large, the magnitude of these differences was not as great. For the ratio, the correlation between methods was excellent, and the ICCs were high for both groups of women. After preservation by boric acid, values of the ratio varied according to acid concentration but not in a linear fashion. Ratio values were similar in urine samples exposed to four different freeze-thaw cycle treatments, although values for all treatments were consistently lower in one batch. Because batch-to-batch variability was not negligible, it is advisable that matched cases and controls be analyzed in the same batch. Provided this is done, the relatively low assay coefficient of variation and high ICC demonstrate that the new ELISA kit can reliably measure the 2-OHE1:16α-OHE1 ratio and detect small case-control differences in large population-based studies, where rapid and relatively easy laboratory methods are critical.
H L Bradlow - One of the best experts on this subject based on the ideXlab platform.
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Predictors of the plasma ratio of 2-Hydroxyestrone to 16alpha-Hydroxyestrone among pre-menopausal, nulliparous women from four ethnic groups.
Carcinogenesis, 2003Co-Authors: Helena Jernström, H L Bradlow, D Sepkovic, Thomas L. Klug, Steven A. NarodAbstract:Studies of circulating estrogen levels in relation to pre-menopausal breast cancer risk have yielded inconsistent results. Various estrogen metabolites might affect the risk differently. Estradiol metabolism occurs primarily via two mutually exclusive pathways, yielding 2-Hydroxyestrone (2-OHE) and 16alpha-Hydroxyestrone (16alpha-OHE). Most, but not all, studies have found that a relatively high 2-OHE/16alpha-OHE ratio is associated with a low breast cancer risk. Our objective was to determine if the 2-OHE/16alpha-OHE ratio in plasma correlates with suspected breast cancer risk factors and other lifestyle factors, such as ethnicity, body size, age at menarche, oral contraceptive use, smoking, vegetarian diet, coffee and alcohol consumption in 513 nulliparous women, aged 17-35. Oral contraceptive users had significantly lower 2-OHE/16alpha-OHE ratios than pill non-users (P = 10(-21)). Among women who were not using oral contraceptives, the median 2-OHE/16alpha-OHE ratio in plasma was similar for white, black, Indian/Pakistani and Asian women, after adjustment for age and menstrual cycle phase. Among oral contraceptive users, Asian women had significantly lower 2-OHE/16alpha-OHE ratios than white women, and this result remained after adjustment for age and day of menstrual cycle. Daily coffee consumption was significantly positively correlated with 2-OHE/16alpha-OHE ratios (r(s) = 0.18, P = 0.002) only among pill non-users. Our findings suggest that the plasma 2-OHE/16alpha-OHE ratio is associated with constitutional factors and with modifiable lifestyle factors. The reported elevated risk of early onset breast cancer among young oral contraceptive users could be mediated in part through altered estrogen metabolism induced by synthetic estrogens and progestins.
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Estrogen Metabolism and Risk of Breast Cancer: A Prospective Study of the 2:16α-Hydroxyestrone Ratio in Premenopausal and Postmenopausal Women
Epidemiology (Cambridge Mass.), 2000Co-Authors: Paola Muti, H L Bradlow, D Sepkovic, Andrea Micheli, Vittorio Krogh, Jo L. Freudenheim, Holger J. Schünemann, Martin Stanulla, Jun Yang, Maurizio TrevisanAbstract:Experimental and clinical evidence suggests that 16alpha-hydroxylated estrogen metabolites, biologically strong estrogens, are associated with breast cancer risk, while 2-hydroxylated metabolites, with lower estrogenic activity, are weakly related to this disease. This study analyzes the association of breast cancer risk with estrogen metabolism, expressed as the ratio of 2-Hydroxyestrone to 16alpha-Hydroxyestrone, in a prospective nested case-control study. Between 1987 and 1992, 10,786 women (ages 35-69 years) were recruited to a prospective study on breast cancer in Italy, the "Hormones and Diet in the Etiology of Breast Cancer" (ORDET) study. Women with a history of cancer and women on hormone therapy were excluded at baseline. At recruitment, overnight urine was collected from all participants and stored at -80 degrees C. After an average of 5.5 years of follow-up, 144 breast cancer cases and four matched controls for each case were identified among the participants of the cohort. Among premenopausal women, a higher ratio of 2-Hydroxyestrone to 16alpha-Hydroxyestrone at baseline was associated with a reduced risk of breast cancer: women in the highest quintile of the ratio had an adjusted odds ratio (OR) for breast cancer of 0.58 [95% confidence interval (CI) = 0.25-1.34]. The corresponding adjusted OR in postmenopausal women was 1.29 (95% CI = 0.53-3.10). Results of this prospective study support the hypothesis that the estrogen metabolism pathway favoring 2-hydroxylation over 16alpha-hydroxylation is associated with a reduced risk of invasive breast cancer risk in premenopausal women.
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a new elisa kit for measuring urinary 2 Hydroxyestrone 16α Hydroxyestrone and their ratio reproducibility validity and assay performance after freeze thaw cycling and preservation by boric acid
Cancer Epidemiology Biomarkers & Prevention, 2000Co-Authors: Roni T Falk, S C Rossi, Thomas R. Fears, H L Bradlow, Herman Adlercreutz, D Sepkovic, Jennifer L. Donaldson, A Migella, Regina G. ZieglerAbstract:There is considerable controversy regarding the role of estrogen metabolites in breast cancer risk, fueled in part by the development of a rapid ELISA that is suitable for large scale investigations. An earlier version of the ELISA could detect values of the 2-Hydroxyestrone (2-OHE1) and 16α-Hydroxyestrone (16α-OHE1) metabolites as low as 2 ng/ml and produce consistent results in premenopausal urines. However, reproducibility was problematic in postmenopausal urines where concentrations of these compounds are much lower. In response to our concern, a new ELISA was developed with a sensitivity of 0.625 ng/ml, which we evaluated using the same pre- and postmenopausal urine samples analyzed in the earlier ELISA. In this report, we present findings on the new kit with regard to reproducibility of the 2-OHE1 and 16α-OHE1 measurements, comparability of results with gas chromatography-mass spectroscopy values, and with regard to the stability of the metabolites after repeated freeze-thaw cycles and after preservation by boric acid. For the most part, we found the new ELISA to be reproducible, with assay coefficients of variation ranging from 10 to 20%, and intraclass correlation coefficients (ICCs) ranging from 80 to 95% in both the pre- and postmenopausal urines. ELISA results for 16α-OHE1 differed from 1 day ( i.e., batch) to the next, and the absolute values of the metabolites obtained by the ELISA were consistently lower than but well correlated with those obtained by gas chromatography-mass spectroscopy. Values of the 2-OHE1:16α-OHE1 ratio also differed between the methods, but because the range of values was not large, the magnitude of these differences was not as great. For the ratio, the correlation between methods was excellent, and the ICCs were high for both groups of women. After preservation by boric acid, values of the ratio varied according to acid concentration but not in a linear fashion. Ratio values were similar in urine samples exposed to four different freeze-thaw cycle treatments, although values for all treatments were consistently lower in one batch. Because batch-to-batch variability was not negligible, it is advisable that matched cases and controls be analyzed in the same batch. Provided this is done, the relatively low assay coefficient of variation and high ICC demonstrate that the new ELISA kit can reliably measure the 2-OHE1:16α-OHE1 ratio and detect small case-control differences in large population-based studies, where rapid and relatively easy laboratory methods are critical.
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Quantifying estrogen metabolism: an evaluation of the reproducibility and validity of enzyme immunoassays for 2-Hydroxyestrone and 16alpha-Hydroxyestrone in urine.
Environmental Health Perspectives, 1997Co-Authors: Regina G. Ziegler, S C Rossi, Thomas R. Fears, H L Bradlow, Herman Adlercreutz, D Sepkovic, P Kiuru, K Wahala, Jimmie B. Vaught, Jennifer L. DonaldsonAbstract:Rapid and simple enzyme immunoassays (EIAs) were recently developed to measure 2-Hydroxyestrone and 16alpha-Hydroxyestrone in unextracted urine. The balance between these competing estrogen metabol...
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2 Hydroxyestrone the good estrogen
Journal of Endocrinology, 1996Co-Authors: H L Bradlow, D Sepkovic, Nitin T Telang, Michael P OsborneAbstract:The issue of the role of 2-Hydroxyestrone (2-OHE1) in breast cancer has been the subject of considerable controversy as to whether it is carcinogenic or anticarcinogenic. The expanding data base outlined below is most consistent with the conclusion that 2-OHE1 is anticarcinogenic. In every experimental model in which 2-hydroxylation was increased, protection against tumors was achieved. Correspondingly, when 2-hydroxylation was decreased, an increase in cancer risk was observed. Even more dramatically, in the case of laryngeal papillomas induction of 2-hydroxylation with indole-3-carbinol (I3C) has resulted in inhibition of tumor growth during the time that the patients continue to take 13C or vegetables rich in this compound.
Malcolm C. Pike - One of the best experts on this subject based on the ideXlab platform.
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Urinary 2-Hydroxyestrone/ 16�-Hydroxyestrone Ratio and Risk of Breast Cancer in Postmenopausal Women
2013Co-Authors: Giske Ursin, Stephanie London, Frank Z. Stanczyk, Gentzschein Annlia Paganini-hill, Ronald K. Ross, Malcolm C. PikeAbstract:Background: It has been suggested that women who metabolize a larger proportion of their endogenous estrogen via the 16�-hydroxylation pathway may be at elevated risk of breast cancer compared with women who metabolize proportionally more estrogen via the 2-hydroxylation pathway. However, the supporting epidemiologic data are scant. Consequently, we compared the ratio of urinary 2-Hydroxyestrone (2-OHE 1) to 16�-Hydroxyestrone (16�-OHE 1) in postmenopausal women with breast cancer and in healthy control subjects. Methods: Estrogen metabolite
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urinary 2 Hydroxyestrone 16α Hydroxyestrone ratio and family history of breast cancer in premenopausal women
Breast Cancer Research and Treatment, 2002Co-Authors: Giske Ursin, Malcolm C. Pike, Stephanie J London, Dongyun Yang, Chiuchen Tseng, Leslie BernsteinAbstract:It has been hypothesized that the ratio of urinary 2-Hydroxyestrone to 16alpha-Hydroxyestrone (2-OHE1/16alpha-OHE1 represents a biomarker for breast cancer risk; the lower the ratio the higher the risk. We obtained early morning urine samples from 70 'high risk' premenopausal women who had a first degree family history of breast cancer and 27 'low risk' women with no such history. Five estrogen metabolites in urine were determined: 2-OHE1, 16alpha-OHE1, estrone (E1), estradiol (E2), and estriol (E3) conjugates. We compared geometric mean levels of each metabolite adjusted for age and weight. 'High risk' women did not have elevated levels of any of these metabolites. Instead, we observed decrements of 3-27% in women with a family history of breast cancer compared with women without such history, this difference was statistically significant for E2, 2- OHE1, and 16alpha-OHE1. The ratio of 2-OHE1/16alpha-OHE1 was identical in women with and without a family history of breast cancer. These results were unchanged, when additionally adjusted for recent intake of alcohol or cruciferous vegetables. Our data suggest that among premenopausal women, family history is not associated with higher urinary estrogen levels or a lower ratio of urinary 2-OHE1/16alpha-OHE1.
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urinary 2 Hydroxyestrone 16α Hydroxyestrone ratio and risk of breast cancer in postmenopausal women
Journal of the National Cancer Institute, 1999Co-Authors: Giske Ursin, Frank Z. Stanczyk, Ronald K. Ross, Stephanie J London, Annlia Paganinihill, Elisabet Gentzschein, Malcolm C. PikeAbstract:BACKGROUND It has been suggested that women who metabolize a larger proportion of their endogenous estrogen via the 16alpha-hydroxylation pathway may be at elevated risk of breast cancer compared with women who metabolize proportionally more estrogen via the 2-hydroxylation pathway. However, the supporting epidemiologic data are scant. Consequently, we compared the ratio of urinary 2-Hydroxyestrone (2-OHE1) to 16alphaHydroxyestrone (16alpha-OHE1) in postmenopausal women with breast cancer and in healthy control subjects. METHODS Estrogen metabolites were measured in urine samples obtained from white women who had participated in a previous population-based, breast cancer case-control study at our institution. All P values are from two-sided tests. RESULTS All of the urinary estrogens measured, with the exception of estriol, were higher in the 66 case patients than in the 76 control subjects. The mean value of urinary 2-OHE1 in case patients was 13.8% (P = .20) higher than that in control subjects, 16alpha-OHE1 was 12.1% (P = .23) higher, estrone was 20.9% higher (P = .14), and 17beta-estradiol was 12.0% higher (P = .36). The ratio of 2-OHE1 to 16alpha-OHE1 was 1.1% higher in the patients (P = .84), contrary to the hypothesis. Compared with women in the lowest third of the values for the ratio of urinary 2-OHE1 to 16alpha-OHE1, women in the highest third were at a nonstatistically significantly increased risk of breast cancer (odds ratio = 1.13; 95% confidence interval = 0.46-2.78), again contrary to the hypothesis. CONCLUSION This study does not support the hypothesis that the ratio of the two hydroxylated metabolites (2-OHE1/16alpha-OHE1) is an important risk factor for breast cancer.
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urinary 2 Hydroxyestrone 16a Hydroxyestrone ratio and risk of breast cancer in postmenopausal women
1999Co-Authors: Giske Ursin, Frank Z. Stanczyk, Stephanie J London, Annlia Paganinihill, Ronald Ross, Malcolm C. PikeAbstract:Background: It has been suggested that women who metabolize a larger proportion of their endogenous estrogen via the 16a-hydroxylation pathway may be at elevated risk of breast cancer compared with women who metabolize proportionally more estrogen via the 2-hydroxylation pathway. However, the supporting epidemiologic data are scant. Consequently, we compared the ratio of urinary 2-Hydroxyestrone (2OHE1 )t o 16a-Hydroxyestrone (16aOHE1) in postmenopausal women with breast cancer and in healthy control subjects. Methods: Estrogen metabolites were measured in urine samples obtained from white women who had participated in a previous populationbased, breast cancer case‐control study at our institution. All P values are from two-sided tests. Results: All of the urinary estrogens measured, with the exception of estriol, were higher in the 66 case patients than in the 76 control sub
Roni T Falk - One of the best experts on this subject based on the ideXlab platform.
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comparison of liquid chromatography tandem mass spectrometry ria and elisa methods for measurement of urinary estrogens
Cancer Epidemiology Biomarkers & Prevention, 2010Co-Authors: Jessica M Faupelbadger, Roni T Falk, Timothy D Veenstra, Larry K Keefer, Barbara J Fuhrman, Robert N Hoover, Regina G. ZieglerAbstract:Absolute and relative concentrations of estrogens and estrogen metabolites are important for clinical decisions as well as for epidemiologic, experimental, and clinical research on hormonal carcinogenesis. RIA and ELISA are routinely used for measuring estrogen metabolites in blood and urine due to efficiency and low cost. Here, we compare absolute and ranked concentrations of estrone, estradiol, and estriol measured by indirect RIA and of 2-Hydroxyestrone and 16alpha-Hydroxyestrone measured by ELISA to the concentrations obtained using a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, which measures 15 estrogen metabolites concurrently. We used overnight urine samples collected from control women (362 premenopausal and 168 postmenopausal) participating in a population-based case-control study of breast cancer among Asian American women ages 20 to 55 years. When comparing RIA or ELISA levels to LC-MS/MS, absolute concentrations for the five estrogen metabolites ranged from 1.6 to 2.9 and 1.4 to 11.8 times higher in premenopausal and postmenopausal women, respectively (all P or =99.6%) and lower coefficients of variation ( or =97.2% and or =95.2% and < or =17.8%). Comparison with the LC-MS/MS method suggests that the widely used RIA and ELISA estrogen metabolite measures may be problematic, especially at low estrogen metabolite levels characteristic of postmenopausal women.
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measuring fifteen endogenous estrogens simultaneously in human urine by high performance liquid chromatography mass spectrometry
Analytical Chemistry, 2004Co-Authors: Timothy D Veenstra, Roni T Falk, Stephen D Fox, John M Roman, Haleem J Issaq, Joseph E Saavedra, Larry K Keefer, Regina G. ZieglerAbstract:A sensitive, specific, accurate, and precise high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry method for measuring the absolute quantities of 15 endogenous estrogens and their metabolites in human urine has been developed and validated. The method requires a single hydrolysis/extraction/derivatization step and only 0.5 mL of urine, yet is capable of simultaneously quantifying estrone and its 2-, 4-methoxy and 2-, 4-, and 16α-hydroxy derivatives, and 2-Hydroxyestrone-3-methyl ether; estradiol and its 2-, 4-methoxy and 2-, 16α-hydroxy derivatives, 16-epiestriol, 17-epiestriol, and 16-ketoestradiol in pre- and postmenopausal women as well as men. Standard curves are linear over a 103-fold concentration range with the standard error of the estimate (SEE) and the relative standard error of the estimate (RSEE) for the linear regression line ranging from 0.0131 to 0.1760 and 1.2 to 7.3%, respectively. The lower limit of quantitation for each estrogen is 0.02 ng/0.5 mL urine...
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a new elisa kit for measuring urinary 2 Hydroxyestrone 16α Hydroxyestrone and their ratio reproducibility validity and assay performance after freeze thaw cycling and preservation by boric acid
Cancer Epidemiology Biomarkers & Prevention, 2000Co-Authors: Roni T Falk, S C Rossi, Thomas R. Fears, H L Bradlow, Herman Adlercreutz, D Sepkovic, Jennifer L. Donaldson, A Migella, Regina G. ZieglerAbstract:There is considerable controversy regarding the role of estrogen metabolites in breast cancer risk, fueled in part by the development of a rapid ELISA that is suitable for large scale investigations. An earlier version of the ELISA could detect values of the 2-Hydroxyestrone (2-OHE1) and 16α-Hydroxyestrone (16α-OHE1) metabolites as low as 2 ng/ml and produce consistent results in premenopausal urines. However, reproducibility was problematic in postmenopausal urines where concentrations of these compounds are much lower. In response to our concern, a new ELISA was developed with a sensitivity of 0.625 ng/ml, which we evaluated using the same pre- and postmenopausal urine samples analyzed in the earlier ELISA. In this report, we present findings on the new kit with regard to reproducibility of the 2-OHE1 and 16α-OHE1 measurements, comparability of results with gas chromatography-mass spectroscopy values, and with regard to the stability of the metabolites after repeated freeze-thaw cycles and after preservation by boric acid. For the most part, we found the new ELISA to be reproducible, with assay coefficients of variation ranging from 10 to 20%, and intraclass correlation coefficients (ICCs) ranging from 80 to 95% in both the pre- and postmenopausal urines. ELISA results for 16α-OHE1 differed from 1 day ( i.e., batch) to the next, and the absolute values of the metabolites obtained by the ELISA were consistently lower than but well correlated with those obtained by gas chromatography-mass spectroscopy. Values of the 2-OHE1:16α-OHE1 ratio also differed between the methods, but because the range of values was not large, the magnitude of these differences was not as great. For the ratio, the correlation between methods was excellent, and the ICCs were high for both groups of women. After preservation by boric acid, values of the ratio varied according to acid concentration but not in a linear fashion. Ratio values were similar in urine samples exposed to four different freeze-thaw cycle treatments, although values for all treatments were consistently lower in one batch. Because batch-to-batch variability was not negligible, it is advisable that matched cases and controls be analyzed in the same batch. Provided this is done, the relatively low assay coefficient of variation and high ICC demonstrate that the new ELISA kit can reliably measure the 2-OHE1:16α-OHE1 ratio and detect small case-control differences in large population-based studies, where rapid and relatively easy laboratory methods are critical.
