Urinary oestrogen steroidome as an indicator of the risk of localised prostate cancer progression.

BACKGROUND: Prostate cancer (PCa) is the most common cancer in North American men. Beyond the established contribution of androgens to disease progression, growing evidence suggest that oestrogen-related pathways might also be of clinical importance. The aim of this study was to explore the association of urinary oestrogen levels with clinical outcomes. METHODS: Urine samples from the prospective multi-institutional PROCURE cohort were collected before RP for discovery (n = 259) and validation (n = 253). Urinary total oestrogens (unconjugated + conjugated), including oestrone and oestradiol, their bioactive and inactive catechol and methyl derivatives (n = 15), were measured using mass spectrometry (MS). RESULTS: The median follow-up time for the discovery and replication cohorts was 7.6 and 6.5 years, respectively. Highly significant correlations between urinary oestrogens were observed; however, correlations with circulating oestrogens were modest. Our findings indicate that higher levels of urinary oestriol and 16-ketoestradiol were associated with lower risk of BCR. In contrast, higher levels of 2-methoxyestrone were associated with an increased risk of development of metastasis/deaths. CONCLUSIONS: Our data suggest that urinary levels of oestriol and 16-ketoestradiol metabolites are associated with a more favourable outcome, whereas those of 2-methoxyestrone are associated with an elevated risk of metastasis after RP. Further studies are required to better understand the impact of oestrogens on disease biology and as easily accessible urine-based risk-stratification markers.

Obesity alters oestrogen metabolism and contributes to pulmonary arterial hypertension.

Obesity is a common comorbidity for pulmonary arterial hypertension (PAH). Additionally, oestrogen and its metabolites are risk factors for the development of PAH. Visceral adipose tissue (VAT) is a major site of oestrogen production; however, the influence of obesity-induced changes in oestrogen synthesis and metabolism on the development of PAH is unclear. To address this we investigated the effects of inhibiting oestrogen synthesis and metabolism on the development of pulmonary hypertension in male and female obese mice.We depleted endogenous oestrogen in leptin-deficient (ob/ob) mice with the oestrogen inhibitor anastrozole (ANA) and determined the effects on the development of pulmonary hypertension, plasma oestradiol and urinary 16α-hydroxyestrone (16αOHE1). Oestrogen metabolism through cytochrome P450 1B1 (CYP1B1) was inhibited with 2,2',4,6'-tetramethoxystilbene (TMS).ob/ob mice spontaneously develop pulmonary hypertension, pulmonary vascular remodelling and increased reactive oxygen species production in the lung; these effects were attenuated by ANA. Oestradiol levels were decreased in obese male mice; however, VAT CYP1B1 and 16αOHE1 levels were increased. TMS also attenuated pulmonary hypertension in male ob/ob mice. Intra-thoracic fat from ob/ob mice and VAT conditioned media produce 16αOHE1 and can contribute to oxidative stress, effects that are attenuated by both ANA and TMS.Obesity can induce pulmonary hypertension and changes in oestrogen metabolism, resulting in increased production of 16αOHE1 from VAT that contributes to oxidative stress. Oestrogen inhibitors are now in clinical trials for PAH. This study has translational consequences as it suggests that oestrogen inhibitors may be especially beneficial in treating obese individuals with PAH.

A randomized, placebo-controlled trial of diindolylmethane for breast cancer biomarker modulation in patients taking tamoxifen.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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. TRIAL REGISTRATION: ClinicalTrials.gov NCT01391689.

Determinación de la relación 2-hidroxiestrona/16x-hidroxiestrona en la orina de mujeres mexicanas como indicador de riesgo a cáncer de mama y su relación con otros factores de riesgo / Determination of 2-hydroxyestrone/16x-hydroxyestrone ratio in urine of Mexican women as a risk indicator for breast cancer and its relationship with other risk factors

La relación 2-hidroxiestrona/16α-hidroxiestrona urinaria (RMEO), se ha propuesto en diversas poblaciones del mundo como indicador de riesgo a cáncer de mama (CM), sin embargo, en la población mexicana, nunca se ha determinado. Objetivo: Determinar la RMEO en mujeres mexicanas y establecer su relación con factores de riesgo para CM. Material y Métodos: Estudio transversal analítico de 142 mujeres premenopáusicas y 42 posmenopáusicas. Se determinó la RMEO con el estuche ESTRAMETTM y se relacionó 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 índice de masa corporal (IMC) y la menarca temprana contribuyeron en 5.4% de su variabilidad (F=5.17; p<0.000). IMC participó en 6.1% de la variabilidad de 2-hidroxiestrona en mujeres premenopáusicas (F=4.40; p<0.000) y 18.1% en posmenopáusicas (F=8.85; p<0.000). Conclusión: La RMEO fue ≈50% menor que lo reportado para otras poblaciones e inversamente proporcional al IMC (AU)

The urinary ratio 2-hydroxyoestrone/16α-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. Objective: To determine URME Mexican women and establish its relationship with risk factors for BC. Material and Methods: 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. Results: 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<0.000). IMC participated in 6.1% of the variability of 2-hydroxyoestrone in premenopausal (F=4.40; p<0.000) and 18.1% in posmenopausal women (F=8.85; p<0.000). Conclusion: The URME was ≈50% lower than reported for other populations and inversely proportional to BMI (AU)

The effect of oral 3,3'-diindolylmethane supplementation on the 2:16α-OHE ratio in BRCA1 mutation carriers.

Hormonal exposures are known to influence breast cancer risk among women with a BRCA1 mutation. Thus, dietary factors that increase the 2-hydroxyestrone (OHE):16α-OHE ratio, a biomarker inversely related to breast cancer development, may also influence cancer risk. We conducted a dietary intervention study to evaluate the ability of 300 mg/day of 3,3'-diindolylmethane (DIM) to increase the urinary 2:16α-OHE ratio in 20 women with a BRCA1 mutation. BRCA1 mutation carriers (n = 15) were assigned to receive 300 mg/day of Rx Balance BioREsponse DIM for 4-6 weeks (intervention group) and five BRCA1 mutation carriers did not take DIM (control group). The urinary 2:16α-OHE ratio was assessed at baseline and after 4-6 weeks by immunoassay. There was no significant effect of DIM on the 2:16α-OHE ratio (2.4 at baseline vs. 3.0 after the intervention, P = 0.35). A short dietary intervention with DIM did not significantly increase the 2:16α-OHE ratio in female BRCA1 mutation carriers. Larger studies investigating the effect of dietary or lifestyle interventions on circulating hormone levels in these high-risk women are warranted.

The ratio of the estradiol metabolites 2-hydroxyestrone (2-OHE1) and 16α-hydroxyestrone (16-OHE1) may predict breast cancer risk in postmenopausal but not in premenopausal women: two case-control studies.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Elevation of C-reactive protein during the luteal phase in healthy adolescents.

INTRODUCTION: Variations in inflammatory markers have been reported in adult women during the luteal phase, but whether these findings are observed during adolescence is unknown. We postulate that higher ultrasensitive C-reactive protein (usCRP) and lower 2-hydroxyestrone (2OHE) levels, an estrogen metabolite with cardioprotective actions, are present during the luteal phase in young women. AIM: To evaluate usCRP levels during the menstrual cycle and to determine its association with 2OHE and 16α-hydroxyestrone (16OHE) in adolescents. METHODS: Healthy postmenarcheal adolescents (N = 37) were studied during one menstrual cycle in follicular phase (FP) and luteal phase-like period (LP-L). RESULTS: Elevations in usCRP levels in the LP-L were observed in the entire group and in anovulatory cycles (1.9 ± 1.1 mg/L in FP to 2.5 ± 1.8 mg/L in LP-L; p < 0.0001). Increases in estrone, estradiol, free and bioavailable estradiol, testosterone, usCRP and 2OHE levels were observed in LP-L compared with FP (p < 0.01), with a borderline elevation in IFG-I levels (p = 0.06). CONCLUSIONS: We report an elevation of usCRP and 2OHE levels during the luteal phase in healthy adolescents. Elevations of this inflammatory marker in anovulatory adolescents without an increase in 2OHE may play a role in metabolic risks associated with chronic anovulation.

[Determination of 2-hydroxyestrone /16α-hydroxyestrone ratio in urine of Mexican women as a risk indicator for breast cancer and its relationship with other risk factors]. / Determinación de la relación 2-hidroxiestrona/16α-hidroxiestrona en la orina de mujeres mexicanas como indicador de riesgo a cáncer de mama y su relación con otros factores de riesgo.

UNLABELLED: 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. OBJECTIVE: To determine URME Mexican women and establish its relationship with risk factors for BC. MATERIAL AND METHODS: 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. RESULTS: 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.

Association between physical activity and urinary estrogens and estrogen metabolites in premenopausal women.

OBJECTIVE: The objective of the study was to evaluate in premenopausal women the relationships of physically active and sedentary behaviors reported for adulthood and adolescence with a comprehensive profile of estrogen metabolism. METHODOLOGY: Fifteen estrogens and estrogen metabolites (jointly termed EM) were measured using liquid chromatography-tandem mass spectrometry in luteal phase urines from 603 premenopausal women in the Nurses' Health Study II. Geometric means of individual EM, metabolic pathway groups, and pathway ratios were examined by level of exposure after adjustment for age, body mass index, alcohol intake, menstrual cycle length, and sample collection timing. RESULTS: High overall physical activity in adulthood (42+ metabolic equivalent h/wk vs. <3 metabolic equivalent h/wk) was associated with a 15% lower level of urinary estradiol (Ptrend=0.03) and 15% lower level of 16-hydroxylation pathway EM (Ptrend=0.03). Levels of 2- and 4-hydroxylation pathway EM did not differ significantly by physical activity. High overall activity was also positively associated with four ratios: 2-pathway EM to parent estrogens (Ptrend=0.05), 2-pathway catechols to parent estrogens (Ptrend=0.03), 2-pathway catechols to methylated 2-pathway catechols (Ptrend<0.01), and 2-hydroxyestrone to 16α-hydroxyestrone (Ptrend=0.01). Similar patterns of association were noted for walking and vigorous physical activity, but there was little evidence of associations with sedentary behaviors or activity during adolescence. CONCLUSIONS: High levels of physical activity were associated with lower levels of parent estrogens and 16-hydroxylation pathway EM and preferential metabolism to 2-pathway catechols. The results of our analysis, the largest, most comprehensive examination of physical activity and estrogen metabolism to date, may be useful in future studies investigating the etiology of diseases linked to both physical activity and endogenous estrogen.

Endocrine metabolic disorders in patients with breast cancer, carriers of BRCA1 gene mutations.

Two groups of breast cancer patients (53±2 years) in clinical remission receiving no specific therapy were examined: group 1, with BRCA1 gene mutations (N=11) and group 2, without mutations of this kind (N=11). The two groups did not differ by insulinemia and glycemia, insulin resistance index, blood levels of thyrotropic hormone, sex hormone-binding globulin, insulin-like growth factor-1, triglycerides, or lipoproteins. In group 1, blood estradiol level was higher. Intensive glucose-induced generation of reactive oxygen species in these patients was associated with a decrease of cholesterolemia, of the C-peptide/insulin proportion, and a trend to higher urinary excretion of 4-hydroxyestrone, one of the most genotoxic catecholestrogens. BRCA1 gene mutations in breast cancer patients were associated with signs of estrogenization and a pro-genotoxic shift in the estrogen and glucose system, which could modulate the disease course and requires correction.

Urinary estrogen metabolites in two soy trials with premenopausal women.

BACKGROUND: Soy consumption may protect against breast cancer through modification of estrogen metabolism. OBJECTIVES: We examined the effect of soy foods on urinary estrogens and the 2-hydroxy (OH)/16α-OH estrone (E(1)) ratio in two dietary interventions with premenopausal women. SUBJECTS/METHODS: The Breast, Estrogens, And Nutrition (BEAN1) study was a 2-year randomized trial and BEAN2 a 13-month randomized crossover study. In both interventions, study participants consumed a high-soy diet with 2 soy food servings/day and a low-soy diet with <3 servings of soy/week. Urine samples were collected at baseline and at the end of the diet periods, analyzed for nine estrogen metabolites by liquid chromatography mass spectrometry, and adjusted for creatinine levels. For BEAN1, two samples for 188 participants and for BEAN2, three samples for 79 women were analyzed. We applied mixed-effects regression models with log-transformed values of estrogen metabolites and soy intake as the exposure variable. RESULTS: In BEAN1, no effect of the high-soy diet on individual estrogen metabolites or hydroxylation pathways was observed. The median 2-OH/16α-OHE(1) ratio decreased non-significantly in the intervention group from 6.2 to 5.2 as compared with 6.8 and 7.2 in the control group (P=0.63). In BEAN2, only 4-OHE(1) was significantly lower after the high-soy diet. Interaction terms of the high-soy diet with equol producer status, ethnicity and weight status revealed no significant effect modification. CONCLUSIONS: Contrary to our hypothesis and some previous reports, the results from two well-controlled dietary interventions do not support an effect of a high-soy diet on a panel of urinary estrogen metabolites and the 2-OH/16α-OHE(1) ratio.

The relation of urinary estrogen metabolites with mammographic densities in premenopausal women.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Increased 2-hydroxylation of estrogen is associated with lower body fat and increased lean body mass in postmenopausal women.

Menopause is associated with changes in bone, muscle and fat mass. The importance of postmenopausal estrogen metabolism in bone health has been established. However, its relationship to body composition in postmenopausal women remains undetermined. The objective of this study is to determine the association between estrogen metabolism and body composition in postmenopausal women. This is a cross sectional study of 97 postmenopausal Caucasian women, 49-80 y.o., ≥1 year from the last normal menstrual period or those who have had oophorectomy. Inactive [2-hydroxyestrone (2OHE(1))] and active [16α-hydroxyestrone (16α-OHE(1))] urinary metabolites of estrogen were measured by ELISA. The whole and regional body composition was measured by DXA. We have found that both 2OHE(1), and 2OHE(1)/16α-OHE(1) ratio were negatively correlated with % total fat, and % truncal fat but positively correlated with % total lean mass. Comparing the fat and lean parameters of body composition according to tertiles of 2OHE(1) and 2OHE(1)/16αOHE(1) ratio showed that subjects in the lowest tertiles, had the highest % total fat, and % truncal fat and the lowest % total lean mass. Multiple regression analysis also showed 2OHE(1) and calcium intake as statistically significant predictors of all body composition parameters. In conclusion, in postmenopausal women, an increase in the metabolism of estrogen towards the inactive metabolites is associated with lower body fat and higher lean mass than those with predominance of the metabolism towards the active metabolites.

Urinary estrogen metabolites during a randomized soy trial.

One of the hypothesized protective mechanisms of soy against breast cancer involves changes in estrogen metabolism to 2-hydroxy (OH) and 16α-OH estrogens. The current analysis examined the effect of soy foods on the 2:16α-OH E(1) ratio among premenopausal women during a randomized, crossover intervention study; women were stratified by equol producer status, a characteristic thought to enhance the protective effects of soy isoflavones. The study consisted of a high-soy diet with 2 soy food servings/day and a low-soy diet with <3 servings of soy/wk for 6 mo each; estrogen metabolites were measured in 3 overnight urines (baseline and at the end of the low- and high-soy diet) using gas chromatography mass spectrometry for the 82 women who completed the study. Urinary isoflavonoids were assessed by liquid chromatography mass spectrometry. When applying mixed models, the 2:16α-OH E(1) ratio increased (P = 0.05) because of a nonsignificant decrease in 16α-OH E(1) (P = 0.21) at the end of the high-soy diet. Similar nonsignificant increases in the 2:16α-OH E(1) ratio were observed in equol producers (P = 0.13) and nonproducers (P = 0.23). These findings suggest a beneficial influence of soy foods on estrogen metabolism regardless of equol producer status.

Metabolic alteration of urinary steroids in pre- and post-menopausal women, and men with papillary thyroid carcinoma.

BACKGROUND: To evaluate the metabolic changes in urinary steroids in pre- and post-menopausal women and men with papillary thyroid carcinoma (PTC). METHODS: Quantitative steroid profiling combined with gas chromatography-mass spectrometry was used to measure the urinary concentrations of 84 steroids in both pre- (n = 21, age: 36.95 ± 7.19 yr) and post-menopausal female (n = 19, age: 52.79 ± 7.66 yr), and male (n = 16, age: 41.88 ± 8.48 yr) patients with PTC. After comparing the quantitative data of the patients with their corresponding controls (pre-menopause women: n = 24, age: 33.21 ± 10.48 yr, post-menopause women: n = 16, age: 49.67 ± 8.94 yr, male: n = 20, age: 42.75 ± 4.22 yr), the levels of steroids in the patients were normalized to the mean concentration of the controls to exclude gender and menopausal variations. RESULTS: Many urinary steroids were up-regulated in all PTC patients compared to the controls. Among them, the levels of three active androgens, androstenedione, androstenediol and 16α-hydroxy DHEA, were significantly higher in the pre-menopausal women and men with PTC. The corticoid levels were increased slightly in the PTC men, while progestins were not altered in the post-menopausal PTC women. Estrogens were up-regulated in all PTC patients but 2-hydroxyestrone and 2-hydroxy-17ß-estradiol were remarkably changed in both pre-menopausal women and men with PTC. For both menopausal and gender differences, the 2-hydroxylation, 4-hydroxylation, 2-methoxylation, and 4-methoxylation of estrogens and 16α-hydroxylation of DHEA were differentiated between pre- and post-menopausal PTC women (P < 0.001). In particular, the metabolic ratio of 2-hydroxyestrone to 2-hydroxy-17ß-estradiol, which could reveal the enzyme activity of 17ß-hydroxysteroid dehydrogenase, showed gender differences in PTC patients (P < 1 × 10-7). CONCLUSIONS: These results are expected be helpful for better understanding the pathogenic differences in PTC according to gender and menopausal conditions.

Effect of flaxseed consumption on urinary levels of estrogen metabolites in postmenopausal women.

Flaxseed is a rich source of dietary lignans. It has been hypothesized that lignans may decrease breast cancer risk through modulation of endogenous hormone levels. The aim of this study was to determine the effect of flaxseed supplementation on urinary levels of estrogen metabolites that may be involved in the development of breast cancer. Forty-three postmenopausal women participated in this 12-wk preintervention-postintervention study. Participants consumed 7.5 g/day of ground flaxseed for 6 wk, followed by 15 g/day for an additional 6 wk. The mean urinary level of 16alpha -hydroxyestrone (16alpha -OHE1) was higher at the end of 12 wk compared to baseline (change of 1.32 ug/day, P = 0.02). There was no significant change in 2-OHE1 excretion. The mean urinary level of the 2-OHE1/16alpha -OHE1 ratio was lower at the end of 12 wk compared to baseline (change of -1.1, P = 0.02). Mean urinary excretion of 2-methoxyestradiol was also lower at 12 wk than at baseline (P = 0.03). Based on the current paradigm of the effects of estrogen metabolism on breast cancer risk, the regimen of dietary flaxseed intake used in this study did not appear to favorably alter breast cancer risk through shifts in estrogen metabolism pathways in postmenopausal women.

Urinary estrogen metabolites and prostate cancer: a case-control study and meta-analysis.

OBJECTIVE: To investigate prostate cancer (Pca) risk in relation to estrogen metabolism, expressed as urinary 2-hydroxyestrone (2-OHE1), 16alpha-hydroxyestrone (16alpha-OHE1) and 2-OHE1 to 16alpha-OHE1 ratio. METHODS: We conducted a case-control study within the Western New York Health Cohort Study (WNYHCS) from 1996 to 2001. From January 2003 through September 2004, we completed the re-call and follow-up of 1092 cohort participants. Cases (n = 26) and controls (n = 110) were matched on age, race and recruitment period according to a 1:4 ratio. We used the unconditional logistic regression to compute crude and adjusted odds ratios (OR) and 95% confident interval (CI) of Pca in relation to 2-OHE1, 16alphaOHE1 and 2-OHE1 to 16alpha-OHE1 by tertiles of urine concentrations (stored in a biorepository for an average of 4 years). We identified age, race, education and body mass index as covariates. We also conducted a systematic review of the literature which revealed no additional studies, but we pooled the results from this study with those from a previously conducted case-control study using the DerSimonian-Laird random effects method. RESULTS: We observed a non-significant risk reduction in the highest tertile of 2-OHE1 (OR 0.72, 95% CI 0.25-2.10). Conversely, the odds in the highest tertile of 16alpha-OHE1 showed a non-significant risk increase (OR 1.76 95% CI 0.62-4.98). There was a suggestion of reduced Pca risk for men in the highest tertile of 2-OHE1 to 16alpha-OHE1 ratio (OR 0.56, 95% CI 0.19-1.68). The pooled estimates confirmed the association between an increased Pca risk and higher urinary levels of 16alpha-OHE1 (third vs. first tertile: OR 1.82, 95% CI 1.09-3.05) and the protective effect of a higher 2-OHE 1 to 16alpha-OHE1 ratio (third vs. first tertile: OR 0.53, 95% CI 0.31-0.90). CONCLUSION: Our study and the pooled results provide evidence for a differential role of the estrogen hydroxylation pathway in Pca development and encourage further study.

Urinary estrogen metabolites in women at high risk for breast cancer.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Daidzein-metabolizing phenotypes in relation to mammographic breast density among premenopausal women in the United States.

BACKGROUND: Mammographic breast density is an established marker of breast cancer risk, and is hormonally sensitive. Studies suggest that production of the daidzein metabolites equol and O-Desmethylangolensin (ODMA) may be associated with hormones and hormonally mediated factors, but few studies have assessed relationships between the capacity to produce these metabolites and breast density. OBJECTIVE: To evaluate the relationship between equol- and ODMA-producer phenotypes and breast density in premenopausal women in the United States. DESIGN: Two hundred and three women attended a clinic visit and 200 provided a urine sample following a 3 day soy challenge. Samples were analyzed for isoflavones by GC-MS to determine daidzein-metabolizing phenotypes. Percent density on recent (<14 month prior to their clinic visit) mammograms was assessed by one reader using a computer-assisted method. Multiple regression analysis was used to assess relationships between the production of equol and ODMA and breast density. Results 55(27.5%) and 182(91%) women were classed as equol- and ODMA-producers (>87.5 ng/ml urine), respectively. In unadjusted and adjusted analyses, there were no differences in breast density between producers and non-producers of either equol or ODMA (P > 0.05). CONCLUSION: In this population of low-soy consuming premenopausal women, there were no associations between daidzein-metabolizing phenotypes and breast density, suggesting that these phenotypes per se do not influence premenopausal breast density.

Treatment with an inhibitor of catechol-O-methyltransferase activity reduces preterm birth and impedes cervical resistance to stretch in pregnant rats.

Catechol-O-methyltransferase (COMT) enzyme catalyzes the methylation of the 2- or 4-hydroxyestrogens to 2- or 4-methoxyestrogens. Both the hydroxyestrogens and methoxyestrogens have been shown to block or enhance the effects of estrogen respectively. Our objective was to investigate the potential role of COMT in parturition and cervical ripening using a rat model. Immunohistochemistry was conducted to detect and localize the COMT protein in rat uterine tissues during pregnancy. We measured the longitudinal changes in urinary 2-hydroxyestrogen before, during, and after pregnancy in rats. Animal studies were conducted to determine the effect of treatment with a selective COMT inhibitor on (1) mifepristone-induced preterm birth and (2) cervical resistance to stretch in pregnant rats. The intensity of staining for the COMT protein differed within the luminal epithelium, uterine gland epithelium, endometrium, and myometrium during pregnancy. Levels of staining for the COMT protein in rat myometrium were highest on day 1 and lowest on days 8 and 13, but high levels returned by days 16 and 19 of pregnancy. The levels of urinary 2-hydroxyestrogen gradually increased in the first 2 weeks of pregnancy, peaked from days 16 to 18 of pregnancy, and then gradually returned to pre-pregnancy levels after delivery. The percentage of pups retained in the uterus of pregnant rats treated with both mifepristone and COMT inhibitor (48 +/- 15%) was significantly higher (P < 0.05) when compared with the value of pregnant rats treated with mifepristone alone (12 +/- 4%). The resistance to stretch was significantly higher (P < 0.05) in cervical tissues from the pregnant rats treated with COMT inhibitor (0.28) when compared with cervical tissues taken from rats treated with vehicle control (0.18). Modulation of COMT activity may play a role in the regulation of myometrial contractility and cervical ripening during pregnancy.