Estrogen levels in nipple aspirate fluid and serum during a randomized soy trial

Role of a Whole Plant Foods Diet in Breast Cancer Prevention and Survival

Breast cancer (BC) is one of the leading causes of death and morbidity among women worldwide. Epidemiologic evidence shows that the risk of BC and other chronic diseases decreases as the proportion of whole plant foods increases, while the proportion of animal foods (fish, meat, poultry, eggs, seafood, and dairy products) and non-whole plant foods (e.g., refined grains, added sugars, French fries) in the diet decreases. Whole plant foods include fruits, vegetables, roots, tubers, whole grains, legumes, nuts, and seeds from which no edible part has been removed and to which no non-whole food been added. A whole plant foods diet lowers insulin resistance, inflammation, excess body fat, cholesterol, and insulin-like growth factor 1 and sex hormone bioavailability; it also increases estrogen excretion, induces favorable changes in the gut microbiota, and may also favorably affect mammary microbiota composition and decrease the risk of early menarche, all contributing to reduced BC incidence, recurrence, and mortality. This review explores the connection between a whole plant foods diet and BC risk and mortality as well as the potential mechanisms involved. Additionally, this diet is compared with other dietary approaches recommended for BC. A whole plant foods diet seems the optimal dietary pattern for BC and overall disease prevention as it exclusively consists of whole plant foods which, based on existing evidence, lead to the best health outcomes.

Early detection of breast cancer through the diagnosis of Nipple Aspirate Fluid (NAF)

The development of breast cancer has been mainly reported in women who have reached the post-menopausal stage; therefore, it is the primary factor responsible for death amongst postmenopausal women. However, if treated on time it has shown a survival rate of 20 years in about two-thirds of women. Cases of breast cancer have also been reported in younger women and the leading cause in them is their lifestyle pattern or they may be carriers of high penetrance mutated genes. Premenopausal women who have breast cancer have been diagnosed with aggressive build-up of tumors and are therefore at more risk of loss of life. Mammography is an effective way to test for breast cancer in women after menopause but is not so effective for premenopausal women or younger females. Imaging techniques like contrast-enhanced MRI can up to some extent indicate the presence of a tumor but it cannot adequately differentiate between benign and malignant tumors. Although the 'omics' strategies continuing for the last 20 years have been helpful at the molecular level in enabling the characteristics and proper understanding of such tumors over long-term longitudinal monitoring. Classification, diagnosis, and prediction of the outcomes have been made through tissue and serum biomarkers but these also fail to diagnose the disease at an early stage. Considerably there is no adequate detection technique present globally that can help early detection and provide adequate specificity, safety, sensitivity, and convenience for the younger and premenopausal women, thereby it becomes necessary to take early measures and build efficient tools and techniques for the same. Through biopsies of nipple aspirate fluid (NAF) biomarker profiling can be performed. It is a naturally secreted fluid from the cells of epithelium found in the breast. Nowadays, home-based liquid biopsy collection kits are also available through which a routine check on breast health can be performed with the help of NAF. Herein, we will review the biomarker screening liquid biopsy, and the new emerging technologies for the examination of cancer at an early stage, especially in premenopausal women.

The health effects of soy: A reference guide for health professionals

Soy is a hotly debated and widely discussed topic in the field of nutrition. However, health practitioners may be ill-equipped to counsel clients and patients about the use of soyfoods because of the enormous, and often contradictory, amount of research that has been published over the past 30 years. As interest in plant-based diets increases, there will be increased pressure for practitioners to gain a working knowledge of this area. The purpose of this review is to provide concise literature summaries (400-500 words) along with a short perspective on the current state of knowledge of a wide range of topics related to soy, from the cholesterol-lowering effects of soy protein to the impact of isoflavones on breast cancer risk. In addition to the literature summaries, general background information on soyfoods, soy protein, and isoflavones is provided. This analysis can serve as a tool for health professionals to be used when discussing soyfoods with their clients and patients.

Nipple Aspirate Fluid at a Glance

Simple Summary

Nipple aspirate fluid (NAF) is a promising source of markers for detection of breast cancer. NAF can be acquired via the nipple by aspiration using a suction device, which is well tolerated by women. Future possible applications of biomarkers for breast cancer derived from NAF could be (1) as a detection tool to identify the initiation of the cancer development process, (2) as an additional tool next to imaging (mammography and breast magnetic resonance imaging) or (3) as a replacement tool for when imaging is not advisable for women, such as during pregnancy and breastfeeding. With this paper, we present a narrative review and perspectives of NAF research at a glance.

Abstract

Nipple aspirate fluid (NAF) is an intraductal mammary fluid that, because of its close proximity to and origin from the tissue from which breast cancer originates, is a promising source of biomarkers for early breast cancer detection. NAF can be non-invasively acquired via the nipple by aspiration using a suction device; using oxytocin nasal spray helps increase yield and tolerability. The aspiration procedure is generally experienced as more tolerable than the currently used breast imaging techniques mammography and breast magnetic resonance imaging. Future applications of NAF-derived biomarkers include their use as a tool in the detection of breast carcinogenesis at its earliest stage (before a tumor mass can be seen by imaging), or as a supporting diagnostic tool for imaging, such as when imaging is less reliable (to rule out false positives from imaging) or when imaging is not advisable (such as during pregnancy and breastfeeding). Ongoing clinical studies using NAF samples will likely shed light on NAF’s content and clinical potential. Here, we present a narrative review and perspectives of NAF research at a glance.

The changing microRNA landscape by color and cloudiness: a cautionary tale for nipple aspirate fluid biomarker analysis

PURPOSE

Investigation of nipple aspirate fluid (NAF)-based microRNAs (miRNAs) as a potential screening tool for women at increased risk of developing breast cancer is the scope of our research. While aiming to identify discriminating NAF-miRNAs between women with different mammographic densities, we were confronted with an unexpected confounder: NAF sample appearance. Here we report and alert for the impact of NAF color and cloudiness on miRNA assessment.

METHODS

Seven classes of NAF colors coupled with cloudiness appearance were established. Using 173 NAF samples from 154 healthy women (19 samples were bilaterally collected), the expression of 14 target and 2 candidate endogenous control (EC) miRNAs was investigated using Taqman Advanced miRNA assays to identify significant differential expression patterns between color-cloudiness classes. Inter- and intra-individual variation of miRNA expression was analyzed using the coefficient of variation (CV).

RESULTS

We found that between the seven NAF classes, fold change miRNA expression differences ranged between 2.4 and 19.6 depending on the interrogated miRNA. Clear NAF samples exhibited higher miRNA expression levels compared to cloudy NAF samples with fold change differences ranging between 1.1 and 6.2. Inter-individual and intra-individual miRNA expression was fairly stable (CV < 15 %), but nevertheless impacted by NAF sample appearance. Within NAF classes, inter-individual variation was largest for green samples (CV 6-15 %) and smallest for bloody samples (CV 2-6 %).

CONCLUSIONS

Our data indicate that NAF color and cloudiness influence miRNA expression and should, therefore, be systematically registered using an objective color classification system. Given that sample appearance is an inherent feature of NAF, these variables should be statistically controlled for in multivariate data analyses. This cautionary note and recommendations could be of value beyond the field of NAF-miRNAs, given that variability in sample color and cloudiness is likewise observed in liquid biopsies such as urine, cerebrospinal fluid and sputum, and could thereby influence the levels of miRNAs and other biomarkers.

Effect of the Intake of Isoflavones on Risk Factors of Breast Cancer-A Systematic Review of Randomized Controlled Intervention Studies

Epidemiological studies suggest that high intake of soy isoflavones may protect against breast cancer, but causal relationships can only be established by experimental trials. Thus, we aimed to provide a systematic review of randomized controlled trials (RCTs) on the effect of an isoflavone intake on risk factors of breast cancer in healthy subjects. After a systematic literature search in PubMed, 18 different RCTs with pre- and/or postmenopausal women were included and investigated for details according to the PRISMA guideline. In these studies, isoflavones were provided by soy food or supplements in amounts between 36.5-235 mg/d for a period of 1-36 months. Breast density, estrogens including precursors, metabolites, estrogen response such as length of menstrual cycle, and markers of proliferation and inflammation were considered. However, in most studies, differences were not detectable between isoflavone and control/placebo treatment despite a good adherence to isoflavone treatment, irrespective of the kind of intervention, the dose of isoflavones used, and the duration of isoflavone treatment. However, the lack of significant changes in most studies does not prove the lack of effects as a sample size calculation was often missing. Taking into account the risk of bias and methodological limitations, there is little evidence that isoflavone treatment modulates risk factors of breast cancer in pre- and postmenopausal women. Future studies should calculate the sample size to detect possible effects and consider methodological details to improve the study quality.

Neither soyfoods nor isoflavones warrant classification as endocrine disruptors: a technical review of the observational and clinical data

Soybeans are a rich source of isoflavones, which are classified as phytoestrogens. Despite numerous proposed benefits, isoflavones are often classified as endocrine disruptors, based primarily on animal studies. However, there are ample human data regarding the health effects of isoflavones. We conducted a technical review, systematically searching Medline, EMBASE, and the Cochrane Library (from inception through January 2021). We included clinical studies, observational studies, and systematic reviews and meta-analyses (SRMA) that examined the relationship between soy and/or isoflavone intake and endocrine-related endpoints. 417 reports (229 observational studies, 157 clinical studies and 32 SRMAs) met our eligibility criteria. The available evidence indicates that isoflavone intake does not adversely affect thyroid function. Adverse effects are also not seen on breast or endometrial tissue or estrogen levels in women, or testosterone or estrogen levels, or sperm or semen parameters in men. Although menstrual cycle length may be slightly increased, ovulation is not prevented. Limited insight could be gained about possible impacts of in utero isoflavone exposure, but the existing data are reassuring. Adverse effects of isoflavone intake were not identified in children, but limited research has been conducted. After extensive review, the evidence does not support classifying isoflavones as endocrine disruptors.

Effects of Dietary Phytoestrogens on Hormones throughout a Human Lifespan: A Review

Dietary phytoestrogens are bioactive compounds with estrogenic activity. With the growing popularity of plant-based diets, the intake of phytoestrogen-rich legumes (especially soy) and legume-derived foods has increased. Evidence from preclinical studies suggests these compounds may have an effect on hormones and health, although the results of human trials are unclear. The effects of dietary phytoestrogens depend on the exposure (phytoestrogen type, matrix, concentration, and bioavailability), ethnicity, hormone levels (related to age, sex, and physiological condition), and health status of the consumer. In this review, we have summarized the results of human studies on dietary phytoestrogens with the aim of assessing the possible hormone-dependent outcomes and health effects of their consumption throughout a lifespan, focusing on pregnancy, childhood, adulthood, and the premenopausal and postmenopausal stages. In pregnant women, an improvement of insulin metabolism has been reported in only one study. Sex hormone alterations have been found in the late stages of childhood, and goitrogenic effects in children with hypothyroidism. In premenopausal and postmenopausal women, the reported impacts on hormones are inconsistent, although beneficial goitrogenic effects and improved glycemic control and cardiovascular risk markers have been described in postmenopausal individuals. In adult men, different authors report goitrogenic effects and a reduction of insulin in non-alcoholic fatty liver patients. Further carefully designed studies are warranted to better elucidate the impact of phytoestrogen consumption on the endocrine system at different life stages.

Breast Hormone Concentrations in Random Fine-Needle Aspirates of Healthy Women Associate with Cytological Atypia and Gene Methylation

Sex steroid hormones contribute to breast cancer development, but data on concentrations of these within breast tissue are limited. We performed simultaneous multiparameter measurement of breast sex steroids, breast epithelial cytology, and DNA methylation in 119 healthy women (54 pre- and 65 postmenopausal) without a history of breast cancer. Random fine-needle aspiration (rFNA) of the breast was performed simultaneously with blood collection. Breast samples were analyzed by LC/MS-MS for estrone, estradiol, progesterone, androstenedione, and testosterone. Blood samples were assayed for estradiol and progesterone by immunoassay. Cytomorphology was classified using the Masood Score, and DNA methylation of eight genes was analyzed using quantitative multiplexed methylation-specific PCR, and expressed as the cumulative methylation index (CMI). Serum and breast concentrations of estradiol and progesterone showed significant correlation (Spearman r = 0.34, P_adj = 0.001 and r = 0.69, P_adj < 0.0006, respectively). Progesterone concentration was significantly higher in the premenopausal breast (P_adj < 0.0008), and showed a luteal surge. Breast estrone and estradiol concentrations did not differ significantly by menopause, but androstenedione concentration was higher in the breasts of postmenopausal women (P = 0.026 and P_adj = 0.208). Breast androgens were significantly correlated with breast density (Spearman r = 0.27, P_adj = 0.02 for testosterone) and CMI (Spearman r = 0.3, P_adj = 0.038 for androstenedione). Our data indicate that future larger studies of breast steroid hormones along with other parameters are feasible. Significant associations of breast androgen concentrations with breast density and gene methylation warrant future study. Cancer Prev Res; 11(9); 557-68. ©2018 AACR.

Evaluation of nipple aspirate fluid as a diagnostic tool for early detection of breast cancer

There has been tremendous progress in detection of breast cancer in postmenopausal women, resulting in two-thirds of women surviving more than 20 years after treatment. However, breast cancer remains the leading cause of cancer-related deaths in premenopausal women. Breast cancer is increasing in younger women due to changes in life-style as well as those at high risk as carriers of mutations in high-penetrance genes. Premenopausal women with breast cancer are more likely to be diagnosed with aggressive tumours and therefore have a lower survival rate. Mammography plays an important role in detecting breast cancer in postmenopausal women, but is considerably less sensitive in younger women. Imaging techniques, such as contrast-enhanced MRI improve sensitivity, but as with all imaging approaches, cannot differentiate between benign and malignant growths. Hence, current well-established detection methods are falling short of providing adequate safety, convenience, sensitivity and specificity for premenopausal women on a global level, necessitating the exploration of new methods. In order to detect and prevent the disease in high risk women as early as possible, methods that require more frequent monitoring need to be developed. The emergence of "omics" strategies over the last 20 years, enabling the characterisation and understanding of breast cancer at the molecular level, are providing the potential for long term, longitudinal monitoring of the disease. Tissue and serum biomarkers for breast cancer stratification, diagnosis and predictive outcome have emerged, but have not successfully translated into clinical screening for early detection of the disease. The use of breast-specific liquid biopsies, such as nipple aspirate fluid (NAF), a natural secretion produced by breast epithelial cells, can be collected non-invasively for biomarker profiling. As we move towards an age of active surveillance, home-based liquid biopsy collection kits are increasingly being applied and these could provide a paradigm shift where NAF biomarker profiling is used for routine breast health monitoring. The current status of established and newly emerging imaging techniques for early detection of breast cancer and the potential for alternative biomarker screening of liquid biopsies, particularly those applied to high-risk, premenopausal women, will be reviewed.

DNA promoter hypermethylation in nipple fluid: a potential tool for early breast cancer detection

Introduction

Nipple fluid aspiration provides direct non-invasive sampling of fluid from the mammary ductal system, where the majority of breast cancers originate. DNA promoter hypermethylation (“methylation”) occurs early and at high frequency in breast carcinogenesis, bearing the potential as a biomarker for cancer detection at its earliest stages. We assessed methylation in nipple fluid from breasts of healthy women, of women with sporadic breast cancer and of their contralateral breasts. Our goal was to investigate whether nipple fluid can be used as a reliable methylation biomarker source.

Methods

Methylation levels of 13 genes were analysed by quantitative multiplex-methylation specific PCR (QM-MSP) in nipple fluid samples from breasts of healthy women, and from the affected and contralateral breasts of breast cancer patients.

Results

Methylation analysis of the low-volume nipple fluid samples was feasible. Despite the generally low methylation levels, cancerous and healthy breasts nipple fluid could be discriminated with an area under the receiver operating characteristic curve (AUC) of 0.64 (p<0.01) based on a multivariate model including AKR1B1, ALX1, RASSF1A and TM6SF1. Within-patient differences between cancerous and contralateral nipple fluid samples were less prominent.

Conclusions

Cancerous nipple fluid contains increased levels of methylation of tumor suppressor genes that potentially could serve as a biomarker for early breast cancer detection.

Soy Food Intake and Biomarkers of Breast Cancer Risk: Possible Difference in Asian Women?

Soy foods may protect against breast cancer in Asian but not in Western populations. We examined if the levels of various markers of breast cancer risk and inflammation, as well as the effects of soy food consumption on these markers, differ between Asian and non-Asian premenopausal women in two soy intervention trials. One study randomized 220 women to a 2-yr intervention and the other one randomized 96 women in a crossover design to examine the effects of consumption of 2 daily soy servings on nipple aspirate fluid (NAF) volume; estrogens in serum, NAF, and urine; insulin-like growth factor-1 (IGF-1), IGF-binding protein 3, and inflammatory markers in serum; and mammographic densities. Mixed linear models were applied to assess ethnic differences in biomarkers and response to the soy diet. Serum C-reactive protein, serum leptin, NAF volume, and NAF estrone sulfate were lower, while urinary isoflavones were higher in Asian than in non-Asian women. A significant interaction (p_interaction = 0.05) between ethnicity and soy diet was observed for IGF-1 but not for other biomarkers. The current findings suggest possible ethnic differences in levels of biomarkers for breast cancer risk but little evidence that Asian women respond differently to soy foods than non-Asian women.

Nipple Aspirate Fluid Hormone Concentrations and Breast Cancer Risk

Prior reports identify higher serum concentrations of estrogens and androgens as risk factors for breast cancer, but steroids in nipple aspirate fluid (NAF) may be more related to risk. Incident breast cancer cases and mammography controls were recruited. Sex steroids were measured in NAF from the unaffected breasts of cases and one breast of controls. Menopausal status and menstrual cycle phase were determined. NAF steroids were purified by HPLC and quantified by immunoassays. Conditional logistic regression models were used to examine associations between NAF hormones and case-control status. NAF samples from 160 cases and 157 controls were evaluable for hormones. Except for progesterone and dehydroepiandrosterone (DHEA), the NAF and serum concentrations were not significantly correlated. NAF estradiol and estrone were not different between cases and controls. Higher NAF (but not serum) DHEA concentrations were associated with cases, particularly among estrogen receptor (ER)-positive cases (NAF odds ratio (OR) = 1.18, 95 % confidence interval (CI) 1.02, 1.36). NAF DHEA was highly correlated with NAF estradiol and estrone but not with androstenedione or testosterone. Higher progesterone concentrations in both NAF and serum were associated with a lower risk of ER-negative cancer (NAF OR = 0.69, 95 % CI 0.51, 0.92). However, this finding may be explained by case-control imbalance in the number of luteal phase subjects (2 cases and 19 controls). The significantly higher concentration of DHEA in NAF of cases and its correlation with NAF estradiol indicates a potentially important role of this steroid in breast cancer risk; however, the negative association of progesterone with risk is tentative.

Methodological considerations in estrogen assays of breast fluid and breast tissue

Estradiol (E2) in nipple aspirate fluid (NAF), ductal lavage fluid (DLF), and random fine needle aspirates (rFNA) are compared. Quantification was by immunoassay or tandem MS. The percent of women yielding NAF varied between 24% and 48% and for DLF was 86.3%. Variation between ducts within a breast was not less than variation between breasts within women but variation between breasts and within women over time was significantly less than variation between women. Serum E2 was highly significantly different among phases of the menstrual cycle but NAF E2 was not different. The correlation between serum and breast fluid E2 concentrations in premenopausal women had coefficients of determination of less than 15%. The correlation between serum and NAF in studies of postmenopausal women varied greatly and may depend on patient selection. The difference between NAF E2 between pre- and postmenopausal women was only 22%; for rFNA it was non-significantly 44% lower in a similar group of postmenopausal women. Progesterone was 96% and 98% lower in postmenopausal NAF and rFNA samples, respectively. Measurements of E2 in breast fluid or breast tissue appears to provide similar estimates of E2 exposure. E2 levels in breast fluid do not reflect the rapid changes that occur in serum and, thus, serum availability of E2 is only one factor determining its levels in the breast. The similarity of levels between breasts and between ducts suggests that estimates of estrogen exposure does not require multiple samples, however, unavailability of fluid may require rFNA in some cases.

Repeated nipple fluid aspiration: compliance and feasibility results from a prospective multicenter study

BACKGROUND

Despite intensive surveillance, a high rate of interval malignancies is still seen in women at increased breast cancer risk. Therefore, novel screening modalities aiming at early detection remain needed. The intraductal approach offers the possibility to directly sample fluid containing cells, DNA and proteins from the mammary ductal system where, in the majority of cases, breast cancer originates. Fluid from the breast can non-invasively be obtained by oxytocin-assisted vacuum aspiration, called nipple fluid aspiration (NFA). The goal of this feasibility study was to evaluate the potential of repeated NFA, which is a critical and essential step to evaluate its possible value as a breast cancer screening method.

METHODS

In this multicenter, prospective study, we annually collected nipple fluid for up to 5 consecutive years from women at increased breast cancer risk, and performed a questionnaire-based survey regarding discomfort of the aspiration. Endpoints of the current interim analyses were the feasibility and results of 994 NFA procedures in 451 women with total follow-up of 560 person years of observation.

RESULTS

In this large group of women at increased risk of breast cancer, repetitive NFA appeared to be feasible and safe. In 66.4% of aspirated breasts, nipple fluid was successfully obtained. Independent predictive factors for successful NFA were premenopausal status, spontaneous nipple discharge, smaller breast size, bilateral oophorectomy and previous use of hormone replacement therapy or anti-hormonal treatment. The procedure was well tolerated with low discomfort. Drop-out rate was 20%, which was mainly due to repeated unsuccessful aspiration attempts. Only 1.6% of women prematurely declined further participation because of side effects.

CONCLUSIONS

Repeated NFA in women at increased breast cancer risk is feasible and safe. Therefore, NFA is a promising method to non-invasively obtain a valuable source of potential breast cancer specific biomarkers.

Oestrogen levels in serum and urine of premenopausal women eating low and high amounts of meat

OBJECTIVE

Based on the hypothesis that high-meat diets may increase breast cancer risk through hormonal pathways, the present analysis compared oestrogens in serum and urine by meat-eating status.

DESIGN

Intervention with repeated measures.

SETTING

Two randomized soya trials (BEAN1 and BEAN2) among premenopausal healthy women.

SUBJECTS

BEAN1 participants completed seven unannounced 24 h dietary recalls and donated five blood and urine samples over 2 years. BEAN2 women provided seven recalls and three samples over 13 months. Serum samples were analysed for oestrone (E₁) and oestradiol (E₂) using RIA. Nine oestrogen metabolites were measured in urine by LC-MS. Semi-vegetarians included women who reported consuming <30 g of red meat, poultry and fish daily, and pescatarians those who reported consuming <20 g of meat/poultry but >10 g of fish daily. All other women were classified as non-vegetarians. We applied mixed models to compute least-square means by vegetarian status adjusted for potential confounders.

RESULTS

The mean age of the 272 participants was 41·9 (SD 4·5) years. Serum E₁ (85 v. 100 pg/ml, P = 0·04) and E₂ (140 v. 154 pg/ml, P = 0·04) levels were lower in the thirty-seven semi-vegetarians than in the 235 non-vegetarians. The sum of the nine urinary oestrogen metabolites (183 v. 200 pmol/mg creatinine, P = 0·27) and the proportions of individual oestrogens and pathways did not differ by meat-eating status. Restricting the models to the samples collected during the luteal phase strengthened the associations.

CONCLUSIONS

Given the limitations of the study, the lower levels of serum oestrogens in semi-vegetarians than non-vegetarians need confirmation in larger populations.

Soy, red clover, and isoflavones and breast cancer: a systematic review

BACKGROUND

Soy and red clover isoflavones are controversial due to purported estrogenic activity and possible effects on breast cancer. We conducted a systematic review of soy and red clover for efficacy in improving menopausal symptoms in women with breast cancer, and for potential impact on risk of breast cancer incidence or recurrence.

METHODS

We searched MEDLINE, Embase, the Cochrane Library, and AMED from inception to March 2013 for human interventional or observational data pertaining to the safety and efficacy of soy and red clover isoflavones in patients with or at risk of breast cancer.

RESULTS

Of 4179 records, we included a total of 131 articles: 40 RCTs, 11 uncontrolled trials, and 80 observational studies. Five RCTs reported on the efficacy of soy for hot flashes, showing no significant reductions in hot flashes compared to placebo. There is lack of evidence showing harm from use of soy with respect to risk of breast cancer or recurrence, based on long term observational data. Soy intake consistent with that of a traditional Japanese diet (2-3 servings daily, containing 25-50mg isoflavones) may be protective against breast cancer and recurrence. Human trials show that soy does not increase circulating estradiol or affect estrogen-responsive target tissues. Prospective data of soy use in women taking tamoxifen does not indicate increased risk of recurrence. Evidence on red clover is limited, however existing studies suggest that it may not possess breast cancer-promoting effects.

CONCLUSION

Soy consumption may be associated with reduced risk of breast cancer incidence, recurrence, and mortality. Soy does not have estrogenic effects in humans. Soy intake consistent with a traditional Japanese diet appears safe for breast cancer survivors. While there is no clear evidence of harm, better evidence confirming safety is required before use of high dose (≥ 100 mg) isoflavones can be recommended for breast cancer patients.

Cytology in nipple aspirate fluid during a randomized soy food intervention among premenopausal women

Because soy food consumption may influence breast tissue activity, we examined its effect on the presence of epithelial cells in nipple aspirate fluid (NAF). In a randomized, crossover design, 82 premenopausal women completed a high-soy and a low-soy diet for 6 mo each, separated by a 1-mo washout period. They provided NAF samples at baseline, 6 mo, and 13 mo during the midluteal phase of the menstrual cycle. Papanicolaou-stained cytology slides (for 33 women at baseline, 24 at low-soy, and 36 at high-soy) were evaluated in women with sufficient NAF. Mixed models evaluated the effect of the high-soy diet on epithelial cytology as compared to baseline and the low-soy diet. At the end of the high-soy diet, cytological subclass had decreased in 8 (24%) and increased in 3 (9%) women as compared to baseline, whereas the respective values were 3 (14%) and 6 (29%) for the low-soy diet samples (P = 0.32). Only the change in subclass indicated a trend in lower cytological class (P = 0.06). Contrary to an earlier report, the number of NAF samples with hyperplastic epithelial cells did not increase after a soy intervention in amounts consumed by Asians.

Expression of epidermal growth factor, transforming growth factor-β1 and adiponectin in nipple aspirate fluid and plasma of pre and post-menopausal women

BACKGROUND

Nipple aspirate fluid (NAF) contains large amounts of protein thought to reflect the microenvironment of the breast, and is of interest in breast cancer prevention research. The correlation between specific NAF proteins to plasma concentrations have not been well studied in healthy women. We collected matched NAF and plasma from 43 healthy pre and postmenopausal women participating in an early phase clinical study to compare the levels of putative cancer protein biomarkers. We compared baseline NAF and plasma levels of epidermal growth factor (EGF), transforming growth factor-beta 1 (TGF-β1), and adiponectin and evaluated menopausal status and body mass index (BMI) as potential modifying factors.

FINDINGS

NAF and plasma levels of EGF, TGF-β1 and adiponectin were not correlated. EGF and TGF-β1 levels in NAF of premenopausal women were significantly higher than postmenopausal women (P's < 0.01). These differences by menopausal status were not observed in plasma. Both NAF and plasma adiponectin levels were non-significantly higher in postmenopausal women. NAF biomarker levels were not associated with BMI whereas plasma EGF, TGF-β1 and adiponectin levels in postmenopausal women were all inversely correlated with BMI (P's < 0.05).

CONCLUSIONS

Protein biomarkers differ significantly between NAF and plasma and are affected differently by both BMI and menopausal status. This study demonstrates important differences in biological information gained by characterizing biomarkers in NAF compared to plasma and suggests each sample source may independently inform on breast cancer risk.

Soy products in the management of breast cancer

PURPOSE OF REVIEW

Meta-analyses of epidemiological studies of soy consumption and breast cancer risk have demonstrated modest protective effects, usually attributed to isoflavones. Concern has been expressed, however, that the estrogenic activity of isoflavones may have adverse effects on breast cancer recurrence.

RECENT FINDINGS

The review covers epidemiological studies that have investigated the impact of soy consumption in breast cancer patients on recurrence and mortality. There are preliminary data to suggest that soy has differential effects on recurrence in human epidermal growth factor receptor-2 positive and human epidermal growth factor receptor-2 negative tumours. Recent studies on mechanisms of action of soy in breast cancer provide insights into epigenetic effects and the interaction of isoflavones with IGF-1 and with a number of polymorphisms of genes associated with breast cancer risk such as MDM2 and CYP1B1.

SUMMARY

Overall, these studies indicate that soy foods consumed at levels comparable to those in Asian populations have no detrimental effects on risk of breast cancer recurrence and in some cases significantly reduce the risk. Importantly, soy does not appear to interfere with tamoxifen or anastrozole therapy. Recent research suggests that women who are at increased risk of breast cancer due to polymorphisms in genes associated with the disease may especially benefit from high soy isoflavone intake.

Urinary estrogen metabolites in two soy trials with premenopausal women

Background

Soy consumption may protect against breast cancer through modification of estrogen metabolism.

Objective

We examined the effect of soy foods on urinary estrogens and the 2-hydroxy (OH)/16α-OH estrone (E₁) ratio in 2 dietary interventions with premenopausal women.

Methods

BEAN1 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 9 estrogen metabolites by liquid chromatography mass spectrometry, and adjusted for creatinine levels. For BEAN1, 2 samples for 188 participants and for BEAN2, 3 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-OH E₁ ratio decreased non-significantly in the intervention group from 6.2 to 5.2 as compared to 6.8 and 7.2 in the control group (p=0.63). In BEAN2, only 4-OHE₁ 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 2 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-OHE₁ ratio.

Nutrition in complementary and alternative medicine

OBJECTIVES

To review the prevalence of nutrition-related complementary and alternative medicine (CAM) used by patients with cancer, to discuss nutrition issues commonly raised by cancer survivors, and to describe how the oncology health care practitioner can best address these issues.

DATA SOURCES

Journal articles, texts, and personal oncology nutrition clinical experience.

CONCLUSION

The interest in and use of special diets and nutrition-related CAM is prevalent in oncology patients. While some nutrition interventions may offer benefit, not all are without risk.

IMPLICATIONS FOR NURSING PRACTICE

Every patient must be assessed for the use of special diets and nutrition-related CAM, any use must be documented, and the person counseled about the pros and cons of these approaches.

Influence of diet on nipple aspirate fluid production and estrogen levels

One possible mechanism how nutritional factors may affect breast cancer risk is through an influence on estrogen levels. Nipple aspirate fluid (NAF) is thought to provide a more direct insight into hormonal influences on breast tissue than serum. The ability to produce NAF may be an indicator of breast cancer risk. The current analysis was conducted as part of a soy trial in 92 premenopausal women and evaluated the relation of usual dietary intake with NAF volume and the most predominant steroidal estrogens in NAF and serum at baseline. Estradiol (E(2)) and estrone sulfate (E(1)S) were assessed in NAF and E(2), estrone (E(1)), and E(1)S, in serum using highly sensitive radioimmunoassays. The statistical analysis applied multivariate, log-linear regression models. Intake of saturated fat and cheese (p = 0.06 for both) indicated a positive trend with NAF volume whereas isoflavonoid and soy consumption suggested inverse associations (p = 0.01 and p = 0.08). For estrogens in NAF, total fat and monounsaturated fat intake was positively associated with E(2) (p = 0.05 and p = 0.02) and in serum, alcohol intake was associated with higher E(1)S levels (p = 0.02). These findings suggest a weak influence of dietary composition on NAF production and estrogen levels in serum and NAF.