2-hydroxyestrone and Breast-Neoplasms

Early epidemiologic studies of estrogen metabolism measured only 2-hydroxyestrone and 16α-hydroxyestrone and relied on direct enzyme immunoassays without purification steps. Eight breast cancer studies have used these assays with prospectively collected blood or urine samples. Results were inconsistent, and generally not statistically significant; but the assays had limited specificity, especially at the low concentrations characteristic of postmenopausal women. To facilitate continued testing in population-based studies of the multiple laboratory-based hypotheses about the roles of estrogen metabolites, a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay was developed to measure concurrently all 15 estrogens and estrogen metabolites in human serum and urine, as unconjugated and total (glucuronidated+sulfated+unconjugated) concentrations. The assay has high sensitivity (lower limit of quantitation ∼1-2 pmol/L), reproducibility (coefficients of variation generally ⩽5%), and accuracy. Three prospective studies utilizing this comprehensive assay have demonstrated that enhanced 2-hydroxylation of parent estrogens (estrone+estradiol) is associated with reduced risk of postmenopausal breast cancer. In the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) cohort, the serum ratio of 2-hydroxylation pathway metabolites to parent estrogens was associated with a 28% reduction in breast cancer risk across extreme deciles (p-trend=.05), after adjusting for unconjugated estradiol and breast cancer risk factors. Incorporating this ratio into a risk prediction model already including unconjugated estradiol improved absolute risk estimates substantially (by ⩾14%) in 36% of the women, an encouraging result that needs replication. Additional epidemiologic studies of the role of estrogen metabolism in the etiology of hormone-related diseases and continued improvement of estrogen metabolism assays are justified.

Topics: Breast Neoplasms; Chromatography, Liquid; Epidemiologic Studies; Estrogens; Female; Humans; Hydroxyestrones; Postmenopause; Premenopause; Prospective Studies; Risk Factors; Tandem Mass Spectrometry

Estradiol can be metabolized to substances eliciting different, partly opposite effects even at low concentrations as shown in own investigations, e. g., regarding (anti)angiogenic actions. Specific anticancerogenic effects are ascribed to 2-hydroxyestrone and particularly 2-methoxyestradiol. In contrast, 16alpha-hydroxyestrone and the 4-hydroxyestrogens may be genotoxic under certain circumstances. Furthermore there are indications that endogenous production of proliferation-stimulating metabolites is raised in some cancers. Especially the urinary excretion of 2-hydroxyestrone to 16alpha-hydroxyestrone was investigated showing in own and other clinical studies a lower ratio in postmenopausal women with breast cancer. Research is ongoing inasfar the determination of estradiol metabolites also in blood or directly in the breast tissue by means of sensitive laboratory methods may allow predictive statements. However, it has be to consider that estradiol metabolism can be influenced by external factors such as nutrition, smoking, sports and drugs such as L-thyroxine and H2-antagonists. We were able to demonstrate that estradiol metabolism during estradiol treatment depends on the application mode and might be differently influenced by addition of the various progestins. Whether the investigation of gene polymorphism of enzymes, which are involved in estradiol metabolism, may be helpful for the assessment or treatment of risk patients, to our opinion needs further research.

Topics: 2-Methoxyestradiol; Anticarcinogenic Agents; Breast Neoplasms; Estradiol; Estrogens, Catechol; Female; Humans; Hydroxyestrones; Male; Neovascularization, Pathologic; Neovascularization, Physiologic; Postmenopause; Prostatic Neoplasms

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.

Topics: Anticarcinogenic Agents; Breast Neoplasms; Estrogens, Catechol; Female; Humans; Hydroxyestrones; Hydroxylation

Some estrogen metabolites are associated with increased breast cancer risk, while others are protective. Research efforts have focused on modifiable factors, including bioactive compounds found in food or supplements, promoting estrogen profiles with anti-cancer properties. EstroSense. A total of 148 premenopausal women were recruited from British Columbia, Canada to participate in a randomized, double-blind, cross-over, multicentre, placebo-controlled study in which women were randomized to a treatment sequence that consisted of either EstroSense. After 12 weeks of intervention, the mean (95% CI) urinary 2-OHE. EstroSense use led to markedly higher urinary 2-OHE1:16α-OHE1 than the placebo, a biomarker associated with a lower risk of breast cancer.. http://clinicaltrials.gov (NCT02385916).

Topics: Biomarkers; Breast Neoplasms; Cross-Over Studies; Estrogens; Female; Humans; Hydroxyestrones

Lignan intake, and its richest food source, flaxseed, have been associated with reduced breast cancer risk. Endogenous sex hormones, such as estrogens, play a role in breast cancer development, and lignans may alter these sex hormone levels. To assess the effect of flaxseed on circulating sex hormones, a randomized controlled trial was conducted among 99 postmenopausal women in Toronto, Canada. The intervention arm consumed 2 tablespoons (15 g) of ground flaxseed daily for 7 weeks; the control arm maintained usual diet. Baseline and week 7 concentrations of 14 serum sex hormones were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and immunoassay, and serum enterolignans (lignan biomarker) using LC-MS/MS. Intervention effects on sex hormone levels were assessed using analysis of covariance. Serum enterolignans increased among the flaxseed arm (+516%). Women consuming flaxseed (vs. controls) had increased serum 2-hydroxyestrone [treatment effect ratio (TER) = 1.54; 95% CI: 1.18-2.00] and 2:16α-hydroxyestrone ratio (TER =1.54; 95% CI: 1.15-2.06); effects on other hormones were not statistically significant. Within the flaxseed arm, change in enterolignan level was positively correlated with changes in 2-hydroxyestrone and 2:16α-hydroxyestrone ratio, and negatively with prolactin. Findings suggest flaxseed affects certain circulating sex hormone levels with possible implications for future breast cancer prevention research.

Topics: Breast Neoplasms; Canada; Diet; Female; Flax; Gonadal Steroid Hormones; Humans; Hydroxyestrones; Lignans; Middle Aged; Postmenopause; Prolactin

Diindolylmethane (DIM), a bioactive metabolite of indole-3-carbinol found in cruciferous vegetables, has proposed cancer chemoprevention activity in the breast. There is limited evidence of clinically relevant activity of DIM or long-term safety data of its regular use. A randomized, double-blind, placebo-controlled trial was conducted to determine the activity and safety of combined use of BioResponse DIM® (BR-DIM) with tamoxifen.. Women prescribed tamoxifen (n = 130) were randomly assigned oral BR-DIM at 150 mg twice daily or placebo, for 12 months. The primary study endpoint was change in urinary 2/16α-hydroxyestrone (2/16α-OHE1) ratio. Changes in 4-hydroxyestrone (4-OHE1), serum estrogens, sex hormone-binding globulin (SHBG), breast density, and tamoxifen metabolites were assessed.. Ninety-eight women (51 placebo, 47 DIM) completed intervention; compliance with treatment was >91%. BR-DIM increased the 2/16α-OHE1 ratio (+3.2 [0.8, 8.4]) compared to placebo (-0.7 [-1.7, 0.8], P < 0.001). Serum SHBG increased with BR-DIM compared to placebo (+25 ± 22 and +1.1 ± 19 nmol/L, respectively). No change in breast density measured by mammography or by MRI was observed. Plasma tamoxifen metabolites (endoxifen, 4-OH tamoxifen, and N-desmethyl-tamoxifen) were reduced in women receiving BR-DIM versus placebo (P < 0.001). Minimal adverse events were reported and did not differ by treatment arm.. In patients taking tamoxifen for breast cancer, daily BR-DIM promoted favorable changes in estrogen metabolism and circulating levels of SHBG. Further research is warranted to determine whether BR-DIM associated decreases in tamoxifen metabolites, including effects on endoxifen levels, attenuates the clinical benefit of tamoxifen.. ClinicalTrials.gov NCT01391689.

Topics: Adult; Antineoplastic Combined Chemotherapy Protocols; Biomarkers, Tumor; Breast Neoplasms; Double-Blind Method; Female; Humans; Hydroxyestrones; Indoles; Mammography; Middle Aged; Sex Hormone-Binding Globulin; Tamoxifen; Time Factors; Treatment Outcome

Mammographic density is a strong predictor of breast cancer risk. The total amount and the metabolism of endogenous estrogens, e.g., the ratio of 2-hydroxyestrone (2-OHE(1)) and 16α-OHE(1) may influence breast cancer risk. This study examined the association of urinary estrogen metabolites with breast density in premenopausal women.. Urine samples were collected at baseline and after 2 years, analyzed for 11 estrogen metabolites plus progesterone and testosterone by liquid chromatography mass spectrometry, and adjusted for creatinine levels. Mixed-effects regression was applied to examine the association of estrogens with breast density.. Total estrogen metabolites (181 ± 113 vs. 247 ± 165 pmol/mg creatinine, p=0.01) and the 2/16α-OH ratio (8.4 ± 10.4 vs. 13.0 ± 17.1, p=0.02) were lower in the 74 Asian than in the 114 non-Asian women. In adjusted models, positive associations of total estrogen metabolites (p=0.002) and the 2/16α-OHE(1) ratio (p=0.08) with percent density were detected in Asians only. In all women, mammographic density was positively associated with the 2-OH pathway (p=0.01), inversely related to the 16α-OH pathway (p=0.01), and not associated with the 4-OH pathway, testosterone, and progesterone. Results for the size of the dense area weakly reflected the findings for percent density, while associations with the non-dense area were in the opposite direction.. The findings that the 2-OH pathway is associated with higher and the 16α-OH pathway with lower breast density contradicts the hypothesized risk profile of these metabolites, but, if a relation between estrogen metabolites and breast cancer risk exists, it may be mediated through pathways other than mammographic density.

Topics: Adult; Asian People; Breast; Breast Neoplasms; Cell Count; Estrogens; Female; Humans; Hydroxyestrones; Mammography; Middle Aged; Premenopause; Progesterone; Risk Assessment; Testosterone

Dietary indoles, present in Brassica plants such as cabbage, broccoli, and Brussels sprouts, have been shown to provide potential protection against hormone-dependent cancers. 3,3'-Diindolylmethane (DIM) is under study as one of the main protective indole metabolites. Postmenopausal women aged 50-70 yr from Marin County, California, with a history of early-stage breast cancer, were screened for interest and eligibility in this pilot study on the effect of absorbable DIM (BioResponse-DIM) supplements on urinary hormone metabolites. The treatment group received daily DIM (108 mg DIM/day) supplements for 30 days, and the control group received a placebo capsule daily for 30 days. Urinary metabolite analysis included 2-hydroxyestrone (2-OHE1), 16-alpha hydroxyestrone (16alpha-OHE1), DIM, estrone (El), estradiol(E2), estriol (E3), 6beta-hydroxycortisol (6beta-OHC), and cortisol in the first morning urine sample before intervention and 31 days after intervention. Nineteen women completed the study,for a total of 10 in the treatment group and 9 in the placebo group. DIM-treated subjects, relative to placebo, showed a significant increase in levels of2-OHE1 (P=0. 020), DIM (P =0. 045), and cortisol (P = 0.039), and a nonsignificant increase of 47% in the 2-OHE1/16alpha-OHE1 ratio from 1.46 to 2.14 (P=0.059). In this pilot study, DIM increased the 2-hydroxylation of estrogen urinary metabolites.

Topics: Aged; Breast Neoplasms; Dietary Supplements; Estradiol; Estriol; Female; Hormones; Humans; Hydrocortisone; Hydroxyestrones; Indoles; Middle Aged; Neoplasm Staging; Postmenopause

Previous studies suggest that the estrogen metabolite 16alpha-hydroxyestrone acts as a breast tumor promoter. The alternative product of estrogen metabolism, 2-hydroxyestrone, does not exhibit estrogenic properties in breast tissue, and lower values of the ratio 2-hydroxyestrone:16alpha-hydroxyestrone (2:16) in urine may be an endocrine biomarker for greater breast cancer risk. Vegetables of the Brassica genus, such as broccoli, contain a phytochemical, which may shift estrogen metabolism and increase the 2:16 ratio. Adding 500 g/day of broccoli to a standard diet shifts 2:16 values upward in humans; however, it is unknown as to whether healthy women are able to consume a sufficient quantity of Brassica to affect breast cancer risk through this mechanism. In this study, 34 healthy postmenopausal women participated in an intensive intervention designed to facilitate the addition of Brassica to the daily diet. The diet was measured by repeated 24-h recall, and estrogen metabolites were measured by enzyme immunoassay in 24-h urine samples. In a crude analysis, there was a nonsignificant increase in the urinary 2:16 ratio associated with greater Brassica consumption. With adjustment for other dietary parameters, Brassica vegetable consumption was associated with a statistically significant increase in 2:16 values, such that for each 10-g/day increase in Brassica consumption, there was an increase in the 2:16 ratio of 0.08 (95% confidence interval, 0.02-0.15). To the extent that the 2:16 ratio, as measured in urine, is associated with breast cancer risk, future research should consider Brassica vegetable consumption as a potentially effective and acceptable dietary strategy to prevent breast cancer.

Topics: Aged; Analysis of Variance; Anticarcinogenic Agents; Brassica; Breast Neoplasms; Estrogens; Female; Humans; Hydroxyestrones; Least-Squares Analysis; Middle Aged; Phytotherapy; Postmenopause

The endogenous metabolism of estrogens is primarily oxidative and involves hydroxylation of the steroid at either C2 (2-OHE1) or C16 (16-OHE1). While the 2-OHE1 metabolites are essentially devoid of peripheral biological activity, 16-OHE1 is an estrogen agonist. There is evidence of an association between the 2-OHE1/16-OHE1 metabolites ratio and breast cancer risk. The CYP1A1 gene may play a role in the 2-hydroxylation (2-OH) of estradiol. African-American women with the wild-type CYP1A1 gene showed a significant increase in the 2-OHE1/16-OHE1 ratio, from 1.35 +/- 0.56 at baseline to 2.39 +/- 0.98 (p = 0.006) after 5 days of treatment with indole-3-carbinol (400 mg/day), a 2-OHE1 inducer. Women with the Msp1 polymorphism showed no significant increase, (0.37% +/- 0.17%). In a case-control study involving 57 women with breast cancer and 312 female controls, the frequency of the homozygous Msp1 polymorphism was 4.2% in African-American controls and 16% in African-American breast cancer cases. The odds ratio of breast cancer with the Msp1 homozygous variant was 8.4 (95% confidence interval: 1.7-41.7). This association was not observed in Caucasian women. The other CYP1A1 polymorphisms were not associated with breast cancer. The CYP1A1 Msp1 polymorphism may be a marker of altered estradiol metabolism and of increased susceptibility to estrogen-related breast cancer in African-Americans.

Topics: Adult; Black People; Breast Neoplasms; Case-Control Studies; Cytochrome P-450 CYP1A1; Estradiol; Estrogen Antagonists; Female; Gene Expression Regulation, Neoplastic; Genotype; Humans; Hydroxyestrones; Indoles; Male; Middle Aged; Polymorphism, Genetic; Risk Factors; RNA, Messenger; White People

Higher levels of circulating estrogens and estrogen metabolites (EMs) have been associated with higher breast cancer risk. In breast tissues, reduced levels of terminal duct lobular unit (TDLU) involution, as reflected by higher numbers of TDLUs and acini per TDLU, have also been linked to elevated breast cancer risk. However, it is unknown whether reduced TDLU involution mediates the risk associated with circulating EMs. In a cross-sectional analysis of 94 premenopausal and 92 postmenopausal women referred for clinical breast biopsy at an academic facility in Vermont, we examined the associations of 15 EMs, quantified using liquid chromatography-tandem mass spectrometry, with the number of TDLUs and acini count/TDLU using zero-inflated Poisson regression with a robust variance estimator and ordinal logistic regression models, respectively. All analyses were stratified by menopausal status and adjusted for potential confounders. Among premenopausal women, comparing the highest vs. the lowest tertiles, levels of unconjugated estradiol (risk ratio (RR) = 1.74, 95 % confidence interval (CI) = 1.06-2.87, p trend = 0.03), 2-hydroxyestrone (RR = 1.74, 95 % CI = 1.01-3.01, p trend = 0.04), and 4-hydroxyestrone (RR = 1.74, 95 % CI = 0.99-3.06, p trend = 0.04) were associated with significantly higher TDLU count. Among postmenopausal women, higher levels of estradiol (RR = 2.09, 95 % CI = 1.01-4.30, p trend = 0.04) and 16α-hydroxyestrone (RR = 2.27, 95 % CI = 1.29-3.99, p trend = 0.02) were significantly associated with higher TDLU count. Among postmenopausal women, higher levels of EMs, specifically conjugated estrone and 2- and 4-pathway catechols, were also associated with higher acini count/TDLU. Our data suggest that higher levels of serum EMs are generally associated with lower levels of TDLU involution.

Topics: Adult; Breast; Breast Neoplasms; Chromatography, Liquid; Cross-Sectional Studies; Estradiol; Female; Humans; Hydroxyestrones; Image-Guided Biopsy; Middle Aged; Postmenopause; Premenopause; Tandem Mass Spectrometry

Two main estradiol metabolites have different biological behavior with tumorigenic features of 16-OHE1 and antiproliferative characteristics of 2-OHE1. We investigated the ratio of these estradiol metabolites in pre- and postmenopausal patients with breast cancer (BC) within two case-control studies.. From 41 premenopausal patients with (cases) and without (controls N = 211) BC and 207 postmenopausal patients with and without BC (N = 206), urine samples were collected. Urine samples were collected prior to surgery and stored at -20 °C until measurement by ELISA. The multiple linear regression test with two interactions was performed to evaluate the influence of different factors on the metabolic ratio.. In premenopausal patients, log ratio of 2-OHE1/16-OHE1 was 0.25 (CI 0.20;0.29) and 0.21 (CI 0.11;0.31) for controls and cases without significant difference. In postmenopausal patients, log ratio was 0.22 (CI 0.17;0.26) and 0.11 (CI 0.07;0.15) in controls and cases, respectively, and was statistically significantly lower (p = 0.0002). Log ratio was significantly influenced by BMI, but only in postmenopausal patients, an increased BMI resulted in a significantly (p < 0.042) decreased ratio.. Our case control studies suggest that in postmenopausal women a different metabolism of estrogens may play a role in the tumorigenesis of breast cancer. This genetically determined metabolism could be influenced by the exogenic factor BMI. In premenopausal women different hormone levels at different time points of the menstrual cycle may be an explanation that why we could not find an influence of estrogen metabolism.

Topics: Adult; Biomarkers; Breast Neoplasms; Case-Control Studies; Enzyme-Linked Immunosorbent Assay; Estradiol; Estrogens; Female; Genetic Predisposition to Disease; Humans; Hydroxyestrones; Middle Aged; Postmenopause; Premenopause; Sensitivity and Specificity

Topics: Animals; Benzhydryl Compounds; Biomarkers; Breast Neoplasms; Drug Synergism; Endocrine Disruptors; Estrone; Genistein; Hydroxyestrones; Male; Microsomes, Liver; Oxidation-Reduction; Phenols; Rats, Wistar

It has been hypothesized that predominance of the 2-hydroxylation estrogen metabolism pathway over the 16α-hydroxylation pathway may be inversely associated with breast cancer risk.. We examined the associations of invasive breast cancer risk with circulating 2-hydroxyestrone (2-OHE1), 16α-hydroxyestrone (16α-OHE1), and the 2-OHE1:16α-OHE1 ratio in a case-control study of postmenopausal women nested within two prospective cohorts: the New York University Women's Health Study (NYUWHS) and the Northern Sweden Mammary Screening Cohort (NSMSC), with adjustment for circulating levels of estrone, and additional analyses by tumor estrogen receptor (ER) status. Levels of 2-OHE1 and 16α-OHE1 were measured using ESTRAMET 2/16 assay in stored serum or plasma samples from 499 incident breast cancer cases and 499 controls, who were matched on cohort, age, and date of blood donation.. Overall, no significant associations were observed between breast cancer risk and circulating levels of 2-OHE1, 16α-OHE1, or their ratio in either cohort and in combined analyses. For 2-OHE1, there was evidence of heterogeneity by ER status in models adjusting for estrone (P ≤ 0.03). We observed a protective association of 2-OHE1 with ER+ breast cancer [multivariate-adjusted OR for a doubling of 2-OHE1, 0.67 (95% confidence interval [CI], 0.48-0.94; P = 0.02)].. In this study, higher levels of 2-OHE1 were associated with reduced risk of ER+ breast cancer in postmenopausal women after adjustment for circulating estrone.. These results suggest that taking into account the levels of parent estrogens and ER status is important in studies of estrogen metabolites and breast cancer.

Topics: Breast Neoplasms; Case-Control Studies; Enzyme-Linked Immunosorbent Assay; Estrogens; Estrone; Female; Humans; Hydroxyestrones; Middle Aged; Postmenopause; Risk

The urinary ratio 2-hydroxyoestrone/16-hydroxyoestrone (URME), has been proposed in various populations on the world as a risk indicator for breast cancer (BC), however in the Mexican population has never been determined.. To determine URME Mexican women and establish its relationship with risk factors for BC.. Cross-sectional study of 142 premenopausal and 42 posmenopausal women. The URME was determined with the kit ESTRAMETTM and was related to risk factors for BC. Correlations and linear regressions were performed.. The median URME was 0.90 (RIQ 0.64-1.18). The body mass index (BMI) and early menarche contribute 5.4% of their variability (F=5.17; p.. La relacion 2-hidroxiestrona/16-hidroxiestrona urinaria (RMEO), se ha propuesto en diversas poblaciones del mundo como indicador de riesgo a cancer de mama (CM), sin embargo, en la poblacion mexicana, nunca se ha determinado. Objetivo: Determinar la RMEO en mujeres mexicanas y establecer su relacion con factores de riesgo para CM. Material y Métodos: Estudio transversal analitico de 142 mujeres premenopausicas y 42 posmenopausicas. Se determino la RMEO con el estuche ESTRAMETTM y se relaciono con factores de riesgo para CM. Se realizaron correlaciones y regresiones lineales. Resultados: La mediana de la RMEO fue 0.90 (RIC: 0.64-1.18). El indice de masa corporal (IMC) y la menarca temprana contribuyeron en 5.4% de su variabilidad (F=5.17; p.

Topics: Adolescent; Adult; Aged; Biomarkers, Tumor; Body Mass Index; Breast Neoplasms; Cross-Sectional Studies; Female; Humans; Hydroxyestrones; Male; Mexico; Middle Aged; Risk Factors; Young Adult

Selective estrogen receptor modulators and a combination of mechanistically distinct chemotherapeutic agents represent conventional therapeutic interventions for estrogen receptor-positive (ER+) clinical breast cancer. Long-term treatment with these agents is associated with acquired tumor resistance and other adverse side effects that impact on patient compliance. Herbal medicines are being widely used in complementary and alternative medicine. However, long-term safety and efficacy of the use of herbal medicines, as well as their interaction with conventional endocrine and chemotherapeutic drug regimens remain largely unknown. The present study utilized a human cell culture model for ER+ clinical breast cancer to examine the potential therapeutic efficacy of an aqueous extract prepared from the fruit of popular Chinese herb Cornus officinalis (CO), also known as Fructus cornii. The human mammary carcinoma-derived MCF-7 cell line represented the model. Status of anchorage-independent growth and cellular metabolism of 17β-estradiol (E₂) represented the quantitative end-point biomarkers for efficacy. MCF-7 cells adapted for growth in serum-depleted medium (0.7% serum, <1 nM E₂) retained their endocrine responsiveness as evidenced by growth promotion by physiological levels of E₂, and growth inhibition by the selective ER modulator tamoxifen at the clinically achievable concentrations. Treatment of MCF-7 cells with CO resulted in inhibition of E₂-stimulated growth in a dose-dependent manner. Similarly, CO treatment also produced a dose-dependent progressive reduction in the number of anchorage-independent colonies, indicating effective reduction of the carcinogenic risk. Treatment of MCF-7 cells with CO at a maximally effective cytostatic concentration resulted in a 5.1-fold increase in the formation of the anti-prolifertive E₂ metabolite 2-hydoxyestrone (2-OHE₁), a 63.6% decrease in the formation of the pro-mitogenic metabolite 16α-hydroxestrone (16-αOHE₁) and a 9.1% decrease in the formation of mitogenically inert metabolite estrone (E₃). These alterations led to a 14.5-fold increase in the 2-OHE₁:16α-OHE₁, and a 3.3-fold increase in the E₃:16α-OHE1 ratios. These data validate a rapid cell culture-based mechanistic approach to prioritize efficacious herbal medicinal products for long-term animal studies and future clinical trials on ER+ clinical breast cancer.

Topics: Antineoplastic Agents, Phytogenic; Breast Neoplasms; Cell Aggregation; Cell Culture Techniques; Cell Line, Tumor; Cell Proliferation; Cornus; Drugs, Chinese Herbal; Estradiol; Female; Fruit; Gas Chromatography-Mass Spectrometry; Humans; Hydroxyestrones; Models, Biological; Plant Extracts; Receptors, Estrogen

Hispanic women are at lower risk for incident breast cancer, but the reasons for this lower risk are unknown. Among postmenopausal women, breast cancer risk is inversely associated with circulating levels of 2-hydroxyestrone but directly associated with levels of 16alpha-hydroxyestrone, according to most studies. Likewise, according to most research, the ratio of 2-hydroxyestrone/16alpha-hydroxyestrone is, therefore, inversely associated with breast cancer risk.. We measured levels of these two circulating estrones as well as estradiol in 40 Hispanic women and 40 non-Hispanic white women who were all postmenopausal and not taking hormones.. Compared with non-Hispanic white women, Hispanic women had 69% higher circulating levels of 2-hydroxyestrone (p = 0.04), and 10% lower levels of 16alpha-hydroxyestrone (p = 0.09). Consequentially, Hispanic women had more favorable estrogen profiles than non-Hispanic white women, with an 89% higher 2:16 ratio (p = 0.01). This finding was not substantially affected by adjustment for other breast cancer risk factors, including matching on body mass index (BMI).. This ethnic difference in estrogen profile requires further research to establish whether there is a causal relationship to breast cancer risk that may, at least partially, explain why postmenopausal Hispanic women have a lower incidence of breast cancer.

Topics: Aged; Body Size; Breast Neoplasms; Cross-Sectional Studies; Female; Follow-Up Studies; Hispanic or Latino; Humans; Hydroxyestrones; Middle Aged; Postmenopause; Risk; White People

This study explored whether average urinary estrogen metabolites in breast cancer high-risk women can be used to identify a subgroup of women at particularly high risk to develop breast cancer, to which prevention strategies should be addressed.. The population consisted of 77 high-risk women, 30 breast cancer patients and 41 controls. All subjects answered a standardized questionnaire; height and weight and spot urine samples were also obtained. Urine hydroxyestrogen metabolites were measured in triplicate by enzyme immunoassay, and the estrogen metabolite ratios for each individual were calculated.. The 2:16 OHE ratio (2-hydroxyestrone/16-alpha-hydroxyestrone) in women at high risk for breast cancer was similar to that observed in the breast cancer group (1.76 +/- 2.33 versus 1.29 +/- 0.80) and lower than in controls (2.47 +/- 1.14; P = 0.00). At the multivariate linear regression model, the 2:16 OHE ratio was significantly associated with diagnosis (P = 0.000 for both the high risk and breast cancer group versus the controls) and body mass index (P = 0.005), but not with age (P = 0.604), or smoking history (P = 0.478).. This study suggests that lower urinary 2:16 OHE ratios are predictors of breast cancer risk. Profiling estrogen metabolites may identify women who are more probably to develop breast cancer within a population of women with known risk factors and may help to further elucidate the clinical relevance of urinary 2:16 OHE ratios as clinical markers and prognostic indicators in this population.

Topics: Adult; Aged; Alcohol Drinking; Body Mass Index; Breast Neoplasms; Female; Humans; Hydroxyestrones; Linear Models; Middle Aged; Smoking

Specific pathways involved in estrogen metabolism may play a role in the etiology of breast cancer. We used data from a large population-based case-control study to assess the association of the urinary estrogen metabolites 2-hydroxyestrone (2-OHE1), 16alpha-hydroxyestrone (16-OHE1), and their ratio (2/16) with both invasive and in situ breast cancer.. Study participants from the Long Island Breast Cancer Study Project provided a spot urine specimen and completed a comprehensive interviewer-administered questionnaire. Women who used exogenous hormones or who took tamoxifen in the 6 months before urine collection were excluded from the analysis, leaving 269 invasive cases, 158 in situ cases, and 326 controls. Unconditional logistic regression was used to obtain adjusted odds ratios (ORs) for invasive and in situ breast cancer, separately, in relation to tertiles of the individual metabolites (standardized for creatinine) and the 2/16 ratio, stratified by menopausal status.. The OR for invasive breast cancer was inversely associated with the 2/16 ratio among premenopausal women (OR = 0.50 for extreme tertiles; 95% confidence interval = 0.25-1.01). ORs ranged from 0.32 to 0.60 when women were stratified by whether cases had received chemotherapy within 6 months before urine collection and by estrogen receptor status. In postmenopausal women, there was a slight reduction in the odds ratio for invasive cancer with high levels of the 2/16 ratio (OR = 0.78; 95% confidence interval = 0.46-1.33). Neither the individual metabolites nor the ratio were associated with in situ breast cancer.. These data provide support for the hypothesis that the 2/16 ratio is associated with reduced breast cancer risk. The most consistent associations were observed with invasive cancer in premenopausal women.

Topics: Aged; Breast Neoplasms; Case-Control Studies; Estrogens; Female; Humans; Hydroxyestrones; Immunoenzyme Techniques; Middle Aged; New York; Surveys and Questionnaires

Most, but not all, studies have found that women with a high urinary 2-hydroxyestrogen (2OHE) to 16alpha-hydroxyestrone (16alphaOHE1) ratio are at reduced risk for breast cancer and have a better prognosis. The aim was to identify factors associated with the pre-operative 2OHE to 16alphaOHE1 ratio and factors that predicted the change in the ratio between the pre-operative visit and first follow-up visit three to six months post-operatively among 59 women with primary ER positive breast cancer tumors. Body measurements, questionnaires and blood samples for measurements of the 2OHE and 16alphaOHE1 plasma levels and CYP1A2 *1F genotyping were collected at both visits. Post-operatively, 15 women received tamoxifen, 30 women tamoxifen and radiotherapy concomitantly, and 14 women radiotherapy. The pre-operative ratio was not correlated with tumor characteristics, but was significantly higher in women who consumed three or more cups of coffee daily (p = 0.009). The number of CYP1A2 *1F C-alleles was correlated with a lower ratio at both visits (p = 0.13 and p = 0.02, respectively). The ratio increased between the two visits in 69.5% of the women. The factors associated with a significant increase in the ratio were concomitant tamoxifen and radiotherapy (p = 0.006), increasing alcohol consumption (p = 0.006), and a high coffee consumption (p = 0.03), but not age or CYP1A2 *1F genotype. In this pilot study, breast cancer patients who started tamoxifen during radiotherapy and who had a moderate coffee and alcohol consumption demonstrated a significant improvement in their estrogen metabolite profile between the pre- and post-operative visits.

Topics: Adjuvants, Pharmaceutic; Aged; Aged, 80 and over; Alcohol Drinking; Breast Neoplasms; Coffee; Cytochrome P-450 CYP1A2; Estrogen Antagonists; Estrogens; Female; Humans; Hydroxyestrones; Hydroxytestosterones; Middle Aged; Pilot Projects; Postoperative Period; Receptors, Estrogen; Tamoxifen

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.

Topics: Administration, Oral; Adolescent; Adult; Black People; Breast Neoplasms; Contraceptive Agents; Estrogen Replacement Therapy; Ethnicity; Female; Humans; Hydroxyestrones; Menstrual Cycle; Parity; Premenopause; Risk Factors; White People

Whether postmenopausal hormone-replacement therapy (HRT) increases the risk of breast cancer remains controversial, despite numerous epidemiological studies. We approached the question from a biochemical rather than an epidemiological direction - we hypothesized that if estrogen administration increases the risk of breast cancer, it should also alter a known estrogen biomarker of risk towards what has been observed in patients who already have breast cancer. The specific biomarker we studied was the ratio of the urinary excretion of two principal estradiol metabolites, 2-hydroxyestrone and 16 alpha-hydroxyestrone, which is markedly decreased in women with breast cancer and women with familial risk for breast cancer. We studied 34 healthy postmenopausal women not on HRT and 19 women on HRT (Premarin 0.625 mg daily plus Provera, 2.5 mg daily, in women with a uterus and Premarin alone in women without a uterus); treatment duration ranged from 3 months to 15 years. We also studied four women with recently diagnosed, untreated breast cancer. The women with breast cancer showed a significantly lower 2-hydroxyestrone to 16 alpha-hydroxyestrone ratio than control women on HRT (1.35 +/- 0.13 vs. 2.71 +/- 0.84; p < 0.0001). There was no significant difference in the metabolite ratio between healthy women on HRT and women not on HRT (2.82 +/- 0.92 vs. 2.71 +/- 0.84). There was no significant difference between women receiving Premarin alone and women receiving Premarin plus Provera (2.46 +/- 0.84 vs. 3.13 +/- 0.90), and neither differed significantly from women not on HRT (2.71 +/- 0.84). The finding that the ratio of women on HRT was not decreased to or toward the ratio in women with breast cancer can be interpreted, we believe, as a suggestive item of biochemical evidence that HRT is not a risk for breast cancer.

Topics: Biomarkers, Tumor; Breast Neoplasms; Cross-Sectional Studies; Estrogen Replacement Therapy; Estrogens, Conjugated (USP); Female; Humans; Hydroxyestrones; Medroxyprogesterone Acetate; Postmenopause; Risk Factors

Women who metabolize a large proportion of their estrogen via the 16alpha hydroxylation pathway could be at a higher risk of breast cancer. The objective of this study was to test the hypothesis that serum concentrations of 2-hydroxyestrone (2-OHE1) and 16alpha-hydroxyestrone (16alpha-OHE1), as well as their ratio, predict the risk of breast cancer in older women.. We performed a case-cohort study of 272 women with confirmed incident breast cancer and 291 controls chosen randomly from the cohort. Estrogen metabolites were measured in serum collected at the baseline examination and stored at -120 degrees C. Incident breast cancers were confirmed by medical records and pathology reports during an average follow-up of 8.7 years.. Mean concentrations of 2-OHE1 and 16alpha-OHE1, adjusted for age and body mass index, were 3% to 4% higher in cases compared with controls: 2-OHE1 was 176 pg/mL and 169 pg/mL and 16alpha-OHE1 was 233 pg/mL and 226 pg/mL in cases and controls, respectively. There was, however, no difference in the ratio of 2-OHE1 to 16alpha-OHE1. The risk of breast cancer in women with the highest quartile of this ratio compared with those in the lowest quartile was 1.17 (95% confidence interval = 0.73-1.87).. The study results do not support the hypothesis that the ratio of 2-OHE1 to 16alpha-OHE1 predicts breast cancer risk.

Topics: Aged; Breast Neoplasms; Case-Control Studies; Cohort Studies; Estrogens; Female; Humans; Hydroxyestrones; Risk Factors; Steroid 16-alpha-Hydroxylase; Surveys and Questionnaires

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.

Topics: Adult; Biomarkers; Breast Neoplasms; Estradiol; Estriol; Estrogens; Estrone; Female; Genetic Predisposition to Disease; Humans; Hydroxyestrones; Middle Aged; Premenopause

Topics: Adolescent; Adult; Asian People; Australia; Black People; Breast Neoplasms; Female; Genotype; Humans; Hydroxyestrones; Native Hawaiian or Other Pacific Islander; Polymorphism, Genetic; Promoter Regions, Genetic; Steroid 17-alpha-Hydroxylase; White People

It has been hypothesized that women who metabolize their endogenous estrogens predominantly via 16(alpha)-hydroxylation rather than via 2-hydroxylation and, as a result, have a low ratio of 2-hydroxyestrone (2-OHE1):16(alpha)-hydroxyestrone (16(alpha)-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 mammographic patterns carried out in a population-based breast screening program in Northern Greece. Urinary levels of 2-OHE1 and 16(alpha)-OHE1 were measured in a random sample of 70 postmenopausal women with P2/DY mammographic patterns and in a random sample of 70 women with N1 mammographic patterns, individually matched to the P2/DY women on year of birth, years since menopause and date of urine collection. Women with a P2/DY pattern had, on average, 58% higher levels of 2-OHE1 (P = 0.002) and 15% higher levels of 16(alpha)-OHE1 (P = 0.37) than those with an N1 pattern. The ratio of 2-OHE1:16(alpha)-OHE1 was 35% higher (P = 0.005) in women with a P2/DY pattern. Women in the highest one-third of this ratio were six times more likely to have a P2/DY pattern than those in the lowest one-third after adjusting for potential confounders (prevalence odds ratio, 6.2; 95% CI, 1.7-22.9; test for linear trend, P = 0.002). These findings seem to suggest that a high, rather than a low, 2-OHE1:16(alpha)-OHE1 ratio may be associated with an increase in breast cancer risk at postmenopausal ages, unless the pathway through which estrogen metabolites may affect breast cancer risk is unrelated to mammographic parenchymal patterns.

Topics: Adult; Aged; Breast Neoplasms; Case-Control Studies; Epidemiologic Studies; Estrogens; Female; Humans; Hydroxyestrones; Mammography; Middle Aged; Postmenopause; Risk Factors; Steroid 16-alpha-Hydroxylase

Asian diets high in soy are associated with lower risk for breast cancer compared with Western diets. Moreover, higher levels of two putative carcinogenic metabolites of 17beta-estradiol, 4- and 16alpha-hydroxyestrogen, and lower amounts of anticarcinogenic metabolites, 2-hydroxyestrogens, have been associated with greater breast cancer risk. In this study, we tested the hypothesis that consumption of a soya diet containing the weakly estrogenic isoflavones genistein and daidzein may alter the metabolism of 17beta-estradiol to 2- and 16alpha-hydroxylated products. Eight pre-menopausal women were placed on a soya-containing, constant diet in a metabolic unit. The diet provided 400 kilocalories from soymilk and 113-202 mg/day (158 +/- 26 mg/day, mean +/- SD) isoflavones daily for a complete menstrual cycle. After a washout period of 4 months, the subjects consumed the same diet, but with soymilk that contained <4.5 mg/day isoflavones ("isoflavone-free"). Urine samples were collected for 24 h daily for the entire cycle during each soya diet period for the analysis of daidzein, genistein, and 2- and 16alpha-hydroxyestrone. Subjects excreted measurable amounts of daidzein (11.6-39.2 mg/day) and genistein (2.9-18.2 mg/day) during the isoflavone-rich soya diet but not during the isoflavone-free soya diet. The diet rich in isoflavones increased the cycle mean daily urinary excretion of 2-hydroxyestrone (averaged over the entire cycle) from 11.6 +/- 2.06 to 17.0 +/- 2.96 nmol/12-h (P = 0.03), a 47% increase. However, the mean daily excretion of 16alpha-hydroxyestrone did not change (7.0 +/- 1.14 nmol/12-h during the isoflavone-free and 7.7 +/- 1.25 nmol/12-h during the isoflavone-rich diet; P = 0.36). The ratio of 2-hydroxyestrone to 16alpha-hydroxyestrone was higher during the isoflavone-rich soya diet (2.6 +/- 0.34) than during the isoflavone-free diet (2.0 +/- 0.32; P = 0.01), a 27% increase. These results suggest that soya isoflavones increase the metabolism of endogenous estrogens to the protective 2-hydroxylated estrogens in women, and this may play an important role in lowering 17beta-estradiol levels and the long-term risk for breast cancer.

Topics: Adult; Breast Neoplasms; Diet; Female; Glycine max; Humans; Hydroxyestrones; Isoflavones; Neoplasms, Hormone-Dependent; Premenopause

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.. 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.. 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.. 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.

Topics: Aged; Breast Neoplasms; Case-Control Studies; Female; Humans; Hydroxyestrones; Immunoenzyme Techniques; Middle Aged; Odds Ratio; Postmenopause; Radioimmunoassay; Risk; Risk Factors; Steroid 16-alpha-Hydroxylase

Topics: Adult; Breast Neoplasms; Female; Humans; Hydroxyestrones; Middle Aged; Postmenopause; Research Design; Risk; Risk Factors

Metabolism of estradiol occurs via two mutually exclusive hydroxylative pathways, yielding metabolites of divergent biological properties. 2-hydroxyestrone (2OHE1) is anti-estrogenic while 16 alpha-hydroxyestrone (16 alpha OHE1) is a potent estrogen. The ratio of 2OHE1 to 16 alpha OHE1 (2/16 alpha-OHE1 ratio) represents the net in vivo estrogenic activity. In this study, we sought to determine if the urinary 2/16 alpha-OHE1 ratio could be a predictor of breast cancer risk and the factors which influence this ratio. Variables analysed included age at diagnosis, menopausal status, parity, use of oral contraceptives, body mass index, serum levels of insulin-like growth factor-I (IGF-I), IGF binding proteins (BPs) and the presence of breast cancer. Serum and urine were collected from 65 breast cancer patients and 36 controls after an overnight fast. Urinary estrogen metabolites were measured by enzyme immunoassays while serum levels of IGF-I, BP-1 and BP-3 were determined by immunoradiometric assays. 2OHE1 levels and 2/16 alpha-OHE1 ratios were significantly lower (P < 0.05) while 16 alpha OHE1 levels were higher (P < 0.01) in cancer patients. Multiple linear regression analysis showed that levels of urinary metabolites were influenced by parity and breast carcinoma. 2/16 alpha-OHE1 ratio correlated positively with serum BP-3 level (P = 0.03). By multiple logistic regression, 2/16 alpha-OHE1 ratio was the most significant factor predictive of breast cancer. The odds ratio for women with higher 2/16 alpha-OHE1 ratios was 0.10 (0.03-0.38, 95% confidence interval). In conclusion, the profile of urinary estradiol metabolites was distinctly altered in breast cancer patients. In addition, BP-3 may be a potential mechanism by which estradiol metabolites influence breast cancer progression. As 16 alpha OHE1 has been shown to initiate neoplastic transformation of mammary epithelial cells, the 2/16 alpha-OHE1 ratio may serve as a biomarker of increased risk of breast cancer.

Topics: Age Factors; Anticarcinogenic Agents; Biomarkers, Tumor; Body Mass Index; Breast Neoplasms; Cell Transformation, Neoplastic; Confidence Intervals; Contraceptives, Oral; Disease Progression; Estradiol; Estrogens, Catechol; Female; Forecasting; Humans; Hydroxyestrones; Hydroxylation; Insulin-Like Growth Factor Binding Protein 1; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Linear Models; Logistic Models; Menopause; Middle Aged; Odds Ratio; Parity; Risk Factors

This is the first prospective study of urinary measures of the two major competing pathways of oestrogen metabolism, 16alpha-hydroxyoestrone (16alpha-OHE1) and 2-hydroxyoestrone (2-OHE1), in relation to incident breast cancer risk. Experimental and case-control study results suggest that metabolism favouring the more oestrogenic 16alpha-OHE1 pathway may be linked to higher breast cancer risk. Women aged 35 and older from Guernsey (n = 5104) were surveyed in 1977-85 and have been continuously monitored for breast cancer and mortality up to the present (Guernsey III, Imperial Cancer Research Fund). Incident cases of breast cancer were matched to three control subjects for comparison of urinary oestrogen metabolite levels measured by enzyme immunoassay (EIA) in spot urine samples collected at baseline and stored frozen for up to 19 years. Consistent with case-control study results, post-menopausal (but not premenopausal) women at baseline who went on to develop breast cancer showed about a 15% lower 2:16alpha-OHE1 ratio than matched control subjects. Further, subjects with metabolite ratios in the highest tertile of 2:16alpha-OHE1 had about a 30% lower risk than women with ratios in the lowest two-thirds, although results were not statistically significant (OR = 0.71, 95% CI = 0.29-1.75). It is of potential importance that, in contrast to most risk factors for breast cancer, such as late age at first birth, oestrogen metabolism appears to be modifiable via diet and exercise, offering women the possibility of lowering breast cancer risk through non-pharmacological measures, although this remains to be tested.

Topics: Adult; Breast Neoplasms; Cohort Studies; Female; Follow-Up Studies; Humans; Hydroxyestrones; Incidence; Predictive Value of Tests; Prospective Studies; Risk Factors

The comparative mitogenic activities of 17beta-estradiol (E2) and four metabolites, 2-hydroxyestradiol (2-OHE2), 2-hydroxyestrone (2-OHE1), 16alpha-hydroxyestradiol (16alpha-OHE2) and 16alpha-hydroxyestrone (16alpha-OHE1) were determined in estrogen receptor (ER)-positive MCF-7 and T47D human breast cancer cells. E2 (1 nM) induced a 7- to 13-fold increase in cell number in both cell lines compared to untreated cells and the mitogenic potencies of 16alpha-OHE1 or 16alpha-OHE2 were comparable to or greater than E2. In contrast, 2-OHE1 and 2-OHE2 were weak mitogens in both cell lines and in cells cotreated with 1 nM E2 and 100 or 1000 nM 2-OHE1 or 2-OHE2, there was a significant inhibition of hormone-induced cell proliferation. The comparative ER agonist/antagonist activities of E2 and the metabolites on transactivation were determined in T47D cells transiently transfected with constructs containing promoter inserts from the cathepsin D (pCD) and creatine kinase B (pCKB) genes. E2, 16alpha-OHE2 and 16alpha-OHE1 induced reporter gene activity in both MCF-7 or T47D cells transfected with pCKB or pCD. In contrast, 2-OHE1 and 2-OHE2 did not exhibit ER agonist activity for these transactivation assays, but in cells cotreated with E2 plus 2-OHE1 or 2-OHE2, there was a significant decrease in the hormone-induced response. These results demonstrate that 16alpha-OHE1/16alpha-OHE2 exhibit estrogenic activities similar to that observed for E2, whereas the 2-catecholestrogens are weak ER agonists (cell proliferation) or antagonists (cell proliferation and transactivation).

Topics: Breast Neoplasms; Cathepsin D; Cell Division; Creatine Kinase; Estradiol; Estriol; Female; Humans; Hydroxyestrones; Isoenzymes; Promoter Regions, Genetic; Receptors, Estrogen; Recombinant Proteins; Transfection; Tumor Cells, Cultured

The two main pathways for metabolizing estrogen are via 16alpha-hydroxylation and 2-hydroxylation. The 16alpha-hydroxy metabolites are biologically active; the 2-hydroxy metabolites are not. It is suggested that women who metabolize a larger proportion of their endogenous estrogen via the 16alpha-hydroxy pathway may be at significantly elevated risk of breast cancer compared with women who metabolize proportionally more estrogen via the 2-hydroxy pathway. In particular, it is suggested that the ratio of urinary 2-hydroxyestrone (2-OHE1) to 16alpha-hydroxyestrone (16alpha-OHE1) is an index of reduced breast cancer risk. This pilot study compared this ratio in postmenopausal women diagnosed with breast cancer to those of healthy controls. Urinary concentrations of estrone (E1), 17beta-estradiol (E2) and estriol (E3) were also quantified. White women who were subjects in a previous breast cancer case-control study at our institution were eligible for inclusion. All participants provided a sample of their first morning urine. The results from the first 25 cases and 23 controls are presented here. The ratio of 2-OHE1 to 16alpha-OHE1 was 12% lower in the cases (p=0.58). However, urinary E1 was 30% higher (p=0.10), E2 was 58% higher (p=0.07), E3 was 15% higher (p=0.48), and the sum of E1, E2, and E3 was 22% higher (p=0.16) in the cases. These preliminary results do not support the hypothesis that the ratio of the two hydroxylation metabolites (2-OHE1/16alpha-OHE1) is an important risk factor for breast cancer or that it is a better predictor of breast cancer risk than levels of E1, E2 and E3 measured in urine.

Topics: Breast Neoplasms; Case-Control Studies; Estradiol; Estriol; Estrone; Female; Humans; Hydroxyestrones; Menopause; Middle Aged; Neoplasms, Hormone-Dependent; Pilot Projects; Risk Factors; Steroid 16-alpha-Hydroxylase

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 metabolism pathways may serve as a biomarker of breast cancer risk. Before testing these assays in epidemiologic studies, we evaluated their reproducibility, and validity relative to gas chromatography-mass spectroscopy (GC-MS). Overnight 12-hr urine collections from five midfollicular premenopausal women, five midluteal premenopausal women, and five postmenopausal women were aliquoted and stored at -70 degrees C. Two aliquots from each woman were assayed with the EIAs in a random, blinded order, monthly over 4 months and 1 year later. Reproducibility over 4 months was good for both metabolites in premenopausal women (coefficient of variation = 8-14%) and satisfactory in postmenopausal women (approximately 19%). Reproducibility over 12 months remained good in premenopausal women, but was poor in postmenopausal women, with mean readings increasing 50 to 100%. Wide variation in estrogen metabolite levels enabled a single EIA measurement to characterize individual differences among premenopausal women in midfollicular (intraclass correlation coefficient = 98-99%) and midluteal phase (85-91%). A narrower range in metabolite levels among postmenopausal women reduced discrimination (78-82%). The correlation between EIA and GC-MS measurement was excellent for both metabolites (r>0.9), except for 2-hydroxyestrone in postmenopausal women (r=0.6). Analysis of absolute agreement suggested that both EIAs were less sensitive than GC-MS, and each detected nonspecific background. The low concentration of estrogen metabolites in urine from postmenopausal women may explain the problems with reproducibility and validity in this menstrual group. Accordingly, more sensitive EIAs have been developed and are now being evaluated.

Topics: Adult; Biomarkers; Breast Neoplasms; Estrogens; Evaluation Studies as Topic; Female; Follicular Phase; Gas Chromatography-Mass Spectrometry; Humans; Hydroxyestrones; Immunoenzyme Techniques; Luteal Phase; Menopause; Middle Aged; Neoplasms, Hormone-Dependent; Reproducibility of Results; Risk Factors

Preliminary studies suggest that the estrogen metabolite 16 alpha-hydroxyestrone is associated with breast cancer, whereas 2-hydroxyestrone is not. However, epidemiological studies evaluating this relationship and taking established risk factors for breast cancer into account are lacking. The purpose of this study was to examine the association of the ratio of the urinary estrogen metabolites (2-hydroxyestrone and 16 alpha-hydroxyestrone) and of the individual metabolites with breast cancer. A spot urine sample, a brief history, and clinical data were collected from breast cancer cases (n = 42) and from women coming to the hospital for a routine mammogram or attending a free breast cancer screening (n = 64). 2-Hydroxyestrone and 16 alpha-hydroxyestrone were measured by enzyme immunoassay, and the estrogen metabolite ratio (EMR; 2-hydroxyestrone:16 alpha-hydroxyestrone) was computed. Cases and controls were similar in terms of age (mean age of cases, 53.8 +/- 15.1 years, versus 54.2 +/- 10.4 years for controls; P = 0.9) and demographics. Mean EMR was not associated with breast cancer overall (1.67 +/- 0.80 versus 1.72 +/- 0.66; P = 0.7). However, in postmenopausal women, the mean EMR was significantly lower in cases compared to controls (1.41 +/- 0.73 versus 1.81 +/- 0.71; P = 0.05). The multivariate adjusted odds ratios for the intermediate and lowest tertiles of the EMR relative to the highest among postmenopausal women were 9.73 (95% confidence interval, 1.27-74.84) and 32.74 (95% confidence interval, 3.36-319.09), respectively. The test for trend was highly significant (P = 0.003). Analyses of the individual metabolites indicated that 16 alpha-hydroxyestrone was a strong risk factor. The EMR did not show any consistent associations with age, race/ethnicity, age at first birth, parity, body mass index, family history of breast cancer, smoking, or alcohol intake. These data suggest a strong, inverse association of the EMR and a strong positive association of 16 alpha-hydroxyestrone with breast cancer in postmenopausal women. Larger studies are needed to confirm these results and to assess the relationship of the EMR and of the individual metabolites with breast cancer, with attention to menopausal status and clinical factors and with adjustment for known breast cancer risk factors.

Topics: Adult; Aged; Biomarkers, Tumor; Breast Neoplasms; Case-Control Studies; Estrogens; Female; Humans; Hydroxyestrones; Middle Aged; New York; Postmenopause; Risk

Xenobiotic estrogens are external compounds with estrogenic activity that may thereby affect the risk of breast cancer. This paper describes a mechanism by which xeno-estrogens may affect the development of breast cancer. Estradiol metabolism proceeds by hydroxylation at one of two mutually exclusive sites at C-2 and C-16 alpha. The catechol pathway yields the weakly estrogenic 2-hydroxyestrone (2-OHE1), which inhibits breast cell proliferation. In contrast, the alternative pathway yields the genotoxic 16 alpha-hydroxyestrone (16 alpha-OHE1), which enhances breast cell growth, increases unscheduled DNA synthesis, and oncogene and virus expression, and increases anchorage-independent growth. Using a radiometric assay that measures the relative formation of 16 alpha-OHE1 versus 2-OHE1 from specifically tritiated estradiol in (ER+) MCF-7 cells, we compared the ratio of 16 alpha-OHE1/2-OHE1 observed after treatment with the known rodent carcinogen 7,12-dimethylbenz[a]anthracene (DMBA) with the ratios after treatment with DDT, atrazine, gamma-benzene hexachloride, kepone, coplanar PCBs, endosulfans I and II, linoleic and eicosapentenoic acids, and indole-3-carbinol (I3C). These pesticides significantly increase the ratio of 16 alpha-OHE1/2-OHE1 metabolites to values comparable to or greater than those observed after DMBA. In contrast, the antitumor agent I3C increased 2-OHE1 formation and yielded ratios that are 1/3 of those found in unexposed control cells and 1/10th of those found in DMBA-treated cells. Thus the ratio of 16 alpha-OHE1/2-OHE1 may provide a marker for the risk of breast cancer. Assays of this ratio, which can be measured in spot urines, may prove useful for a variety of in vitro and in vivo studies bearing on breast cancer risk.

Topics: Biomarkers; Breast Neoplasms; Estradiol; Estrogens, Catechol; Humans; Hydroxyestrones; Insecticides; Tumor Cells, Cultured

Topics: Animals; Asian People; Breast Neoplasms; Estrogens; Estrogens, Catechol; Female; Humans; Hydroxyestrones; Mammary Neoplasms, Experimental; White People

Catechol estrogens such as 2-OH estrone are interesting estrogen metabolites formed in several human tissues and excreted in urine. We developed and thoroughly validated a radioimmunoassay for urinary 2-OH estrone that has several advantages over published RIAs. Because we developed a relatively specific antiserum, we did not include a preliminary chromatographic step to eliminate cross-reacting urinary steroids. We hydrolyzed urinary steroid conjugates with beta-glucuronidase from Helix pomatia because recoveries after acid hydrolysis were only 49.6% compared with 73.8% after enzyme hydrolysis. Published RIAs for urinary 2-OH estrone use acid hydrolysis. Our RIA measured 2-OH estrone independently of the volume of sample, and the detection limit was between 100 and 240 ng/L (10-24 pg per tube). The ED50 was 370 ng/L, and inter- and intraassay CVs for low, medium, and high concentrations were 22.5%, 22.8%, and 19.9%, and 17.4%, 14.3%, and 10.8%, respectively. Median concentrations measured in 14 controls and 33 postmenopausal patients with breast cancer were 0.96 and 1.55 micrograms/g creatinine, respectively, but there was considerable overlap between values from controls and patients.

Topics: Adult; Breast Neoplasms; Drug Stability; Female; Humans; Hydrolysis; Hydroxyestrones; Menstruation; Postmenopause; Radioimmunoassay; Reference Values; Sensitivity and Specificity

In order to investigate the estrogen metabolism in human breast cancer, the estradiol 2- and 16 alpha-hydroxylase (2-, 16 alpha-OHase) activities were determined in the microsomal fractions of human breast tissues by using reverse-phase HPLC. The effects of estrogen metabolites on the cell proliferation were also examined by employing two human breast cancer cell lines. The 2-OHase activity was detected in most cancerous and noncancerous tissues, but the value in cancerous tissues was significantly lower than that in noncancerous tissues (p less than 0.05). Patients without lymph node metastases showed relatively higher activity than those with metastases (0.05 less than p less than 0.1). The 16 alpha-OHase activity was, however, found in only 23% of cancerous tissues. Among those, the activity was present in 52% of ER positive cancerous tissues, but almost absent in ER negative ones. The growth ER positive cell line, MCF-7, was suppressed with 2-hydroxyestrone and stimulated with 16 alpha-hydroxyestrone. The cell proliferation stimulated with 16 alpha-hydroxyestrone was not inhibited by the addition of tamoxifen, a strong antagonist of estradiol. Two metabolites had no effect on the growth of ER negative cell line, MDA-MB-231. These results suggest that estrogen metabolites influence the proliferation of human breast cancer cells as the endogenous regulatory factors and should be considered for the future endocrine therapy.

Topics: Adolescent; Adult; Aged; Aryl Hydrocarbon Hydroxylases; Breast Neoplasms; Cell Division; Cytochrome P-450 CYP1A1; Cytochrome P-450 Enzyme System; Estrogens; Female; Humans; Hydroxyestrones; Middle Aged; Receptors, Estrogen; Steroid 16-alpha-Hydroxylase; Steroid Hydroxylases; Tumor Cells, Cultured

Catecholestrogens and especially 2-hydroxyestrone (2OH-E1) are estradiol metabolites locally formed in breast cancer cells. The present study demonstrates that the two parent compounds, estradiol (E2) and its metabolite 2OH-E1, exert opposite effects on hormone-sensitive breast cancer cell growth assessed by cell counts and transferrin receptor levels, and also on cell differentiation assessed by secreted proteins such as alpha-lactalbumin and gross cystic disease fluid protein (GCDFP-15). The present findings may highlight estradiol regulation in hormone-sensitive breast cancer cells.

Topics: Breast Neoplasms; Cells, Cultured; Estradiol; Estrogens, Catechol; Estrone; Female; Humans; Hydroxyestrones; Receptors, Progesterone; Receptors, Transferrin

The binding of 2-hydroxyestrone (2OH E1), a catecholestrogen which is the main end product of the 2-hydroxylation of estrogen, was investigated in breast cancers. 2OH E1-specific bindings were found in the cytosol (Kd = 0.54 +/- 0.10 nM) and in the endoplasmic reticulum (Kd = 3.36 +/- 1.32 nM). The dissociation rate constants of complexes between [3H]2OH E1 and cytosol or membrane binding sites were 3.30 h-1 and 8.30 h-1 respectively. Qualitative analysis of [3H]2OH E1 cytosolic complexes demonstrated a specific binding component with a mol. wt of 330,000 Daltons. Specificity experiments showed that nonestrogenic hormones were unable to compete with 2OH E1 for its binding sites, whereas triphenylethylene derivatives and catecholamines were potent 2OH E1 competitors. The presence of 2OH E1 specific bindings suggests a potential role of catecholestrogen in breast cancer.

Topics: Binding Sites; Breast Neoplasms; Catechol O-Methyltransferase; Cell Fractionation; Chromatography, High Pressure Liquid; Estrogens, Catechol; Female; Humans; Hydroxyestrones; Receptors, Estrogen; Structure-Activity Relationship; Time Factors; Tritium

The estrogen responsive human breast cancer MCF-7 cell culture was examined for its response to 2-hydroxyestrone a principal metabolite of estradiol. Addition of 2-hydroxyestrone to the cell cultures in concentration of 10(-9) - 10(-6) M had no effect on cell growth and proliferation because of rapid O-methylation of the catechol estrogen by catechol O-methyltransferase which is highly active in these cells. In the presence of quinalizarin, a potent catechol O-methyltransferase inhibitor which reduces the O-methylation of the steroid, 10(-7) M and 10(-8) M 2-hydroxyestrone markedly suppresses the growth and proliferation of the cells. The tumor cell growth-inhibitory action of the catechol estrogen was neutralized by the presence of 10(-9) M estradiol. The catechol estrogen inhibition of cell growth is not observed in the estrogen receptor-negative human breast cancer cell lines MDA-MB-231 and MDA-MB-330 providing evidence that the inhibition is specific and is estrogen receptor-mediated. In contrast, the 16 alpha-hydroxylated metabolites of estradiol, estriol and 16 alpha-hydroxyestrone, are effective stimulators of MCF-7 cell proliferation with the latter exhibiting potency in excess of that expected from its estrogen receptor affinity. The present results represent the first observation of a specific receptor-mediated antiestrogenic action of 2-hydroxyestrone and suggest that the physiological regulation of the agonist activity of the primary estrogen may involve in situ generation of catechol estrogen.

Topics: Breast Neoplasms; Cell Division; Cell Line; Estradiol; Estrogen Antagonists; Estrogens, Catechol; Estrone; Female; Humans; Hydroxyestrones; Kinetics; Receptors, Estrogen