Hormone levels in older women: a study of post-menopausal breast cancer patients and healthy population controls

Differences in Postoperative Pain, Nausea, and Vomiting After Elective Laparoscopic Cholecystectomy in Premenopausal and Postmenopausal Mexican Women

BACKGROUND

Postoperative symptoms and pain after laparoscopic cholecystectomy (LC) are common in women. However, there is no evidence of differences in incidence and severity among different age groups. We evaluated whether adverse postoperative symptoms were more common in younger than in older women after LC.

METHODS

One hundred and fifty premenopausal (mean age 37.6 ± 3.6 y) and 145 postmenopausal women (59 ± 5.2 y) were included in this retrospective cohort study. Clinical and anthropometric parameters were analyzed. Study endpoints were the incidences of postoperative nausea and vomiting (PONV) and pain, and the additional analgesics and antiemetics needed after surgery.

RESULTS

Body mass index was normal in 42.7% of patients in the younger group and 64.8% in the older group (P < 0.001). Reported pain was more frequent and intense in the younger group throughout the study period (P < 0.01). Additional narcotics were required in 18% of premenopausal versus 7.6% of postmenopausal women (P = 0.001), and the doses used to reduce pain were higher for premenopausal women (P = 0.02). PONV was more frequent in the younger group at 1 and 6 h after surgery (P < 0.005). Rescue antiemetics were required in 29 premenopausal and 13 postmenopausal women (P = 0.01). Hospital stay was shorter for the older patients (P = 0.01). Minor morbidity was observed in both groups (0.7% and 2.1%). There was no mortality.

CONCLUSIONS

Early PONV and pain after LC were more frequent in premenopausal women, who also required more rescue analgesic and antiemetic medication.

Endogenous estrogens-breast cancer and chemoprevention

Breast cancer is the most common female malignancy and the second leading cause of cancer related deaths. It is estimated that about 40% of all cancer in women is hormonally mediated. Both estrogens and androgens play critical roles in the initiation and development of breast cancer. Estrogens influence normal physiological growth, proliferation, and differentiation of breast tissues, as well as the development and progression of breast malignancy. Breast cancer is caused by numerous endo- and exogenous risk factors. The paper presents estrogen metabolism, in particular 17β-estradiol and related hormones. The mechanisms of estrogen carcinogenesis include the participation of estrogen receptors, the genotoxic effect of the estrogen metabolites, and epigenetic processes that are also presented. The role of reactive oxygen species in breast cancer has been described. It called attention to a role of numerous signaling pathways in neoplastic transformation. Chemoprotective agents, besides other phytoestrogens, classical antioxidants, synthetic compounds, and their mechanisms of action have been shown.

Role of organophosphorous pesticides and acetylcholine in breast carcinogenesis

Breast cancer is the leading cause of cancer-related death in women worldwide. Several studies have addressed the association between cancer in humans and agricultural pesticide exposure. Evidence indicates that exposure to organophosphorous pesticides such as parathion and malathion occurs as a result of occupational factors since they are extensively used to control insects. On the other hand, estrogens have been considered beneficial to the organism; however, epidemiological studies have pointed out an increased breast cancer risk in both humans and animals. Experimental female rat mammary gland cancer models were developed after exposure to parathion, malathion, eserine, an acetylcholinesterase inhibitor, and estrogen allowing the analysis of the signs of carcinogenicity as alteration of cell proliferation, receptor expression, genomic instability, and cell metabolism in vivo and in vitro. Thus, pesticides increased proliferative ducts followed by ductal carcinoma; and 17β-estradiol increased proliferative lobules followed by lobular carcinomas. The combination of both pesticides and either eserine or estrogen induced tumors with both types of structures followed by mammary gland tumors and metastasis to the lung and kidneys after 240 days of a 5-day treatment. Studies also showed that these pesticides and eserine decreased three to five times the acetylcholinesterase activity in the serum compared to controls whereas terminal end buds increased in number, being inhibited by atropine. Genomic instability was analyzed in such tissues (mp53, CYP1A2, c-myc, c-fos, ERα, M2R) and pesticides increased protein expression that was stimulated by estrogens but inhibited by atropine. Eserine also transformed the epithelium of the rat mammary gland in the presence of estrogen and increased the number of terminal end buds after treatment inducing mammary carcinomas. Then, enzymatic digestion of such structures gave rise to cells with increased DNA synthesis and induced anchorage independence. Thus, there were changes in the epithelium of the mammary gland influencing breast carcinogenesis. Furthermore, these substances and acetylcholine also showed the signs of carcinogenicity in vitro as cell proliferation, receptor expression (ERα, ErbB2, M2R), genomic instability (c-myc, mp53, ERα, M2R), and cell metabolism. A unique cellular model is also presented here based on the use of MCF-10 F, a non-tumorigenic cell line that represents a valuable clinically translatable experimental approach that identifies mechanistic links for pesticides and estrogen as suspect human carcinogenic agents.

Signs of carcinogenicity induced by parathion, malathion, and estrogen in human breast epithelial cells (Review)

Cancer development is a multistep process that may be induced by a variety of compounds. Environmental substances, such as pesticides, have been associated with different human diseases. Organophosphorus pesticides (OPs) are among the most commonly used insecticides. Despite the fact that organophosphorus has been associated with an increased risk of cancer, particularly hormone-mediated cancer, few prospective studies have examined the use of individual insecticides. Reported results have demonstrated that OPs and estrogen induce a cascade of events indicative of the transformation of human breast epithelial cells. In vitro studies analyzing an immortalized non-tumorigenic human breast epithelial cell line may provide us with an approach to analyzing cell transformation under the effects of OPs in the presence of estrogen. The results suggested hormone-mediated effects of these insecticides on the risk of cancer among women. It can be concluded that, through experimental models, the initiation of cancer can be studied by analyzing the steps that transform normal breast cells to malignant ones through certain substances, such as pesticides and estrogen. Such substances cause genomic instability, and therefore tumor formation in the animal, and signs of carcinogenesis in vitro. Cancer initiation has been associated with an increase in genomic instability, indicated by the inactivation of tumor-suppressor genes and activation of oncogenes in the presence of malathion, parathion, and estrogen. In the present study, a comprehensive summary of the impact of OPs in human and rat breast cancer, specifically their effects on the cell cycle, signaling pathways linked to epidermal growth factor, drug metabolism, and genomic instability in an MCF-10F estrogen receptor-negative breast cell line is provided.

Oxidative stress in female cancers

Breast, cervical and ovarian cancers are highly prevalent in women worldwide. Environmental, hormonal and viral-related factors are especially relevant in the development of these tumors. These factors are strongly related to oxidative stress (OS) through the generation of reactive oxygen species (ROS). The OS is caused by an imbalance in the redox status of the organism and is literally defined as "an imbalance between ROS generation and its detoxification by biological system leading to impairment of damage repair by cell/tissue". The multistep progression of cancer suggests that OS is involved in cancer initiation, promotion and progression. In this review, we described the role of OS and the interplay with environmental, host and viral factors related to breast, cervical and ovarian cancers initiation, promotion and progression. In addition, the role of the natural antioxidant compound curcumin and other compounds for breast, cervical and ovarian cancers prevention/treatment is discussed.

Hormonal Profiles and Estrogen Receptors in Egyptian Female Breast Cancer Patients

AIMS AND BACKGROUND

Hormones are considered to be an important factor in the etiology of breast cancer. Serum hormonal profiles of premenopausal and postmenopausal breast cancer patients as well as estrogen receptor (ER) concentrations in breast cancer tissues were examined in an attempt to establish a possible association between hormones and breast cancer risk and to elucidate the biological features of the disease among Egyptian female patients.

METHODS

Levels of estradiol (E2), testosterone (T), progesterone (P), LH, FSH, prolactin, T3, T4 and TSH were measured by highly specific radioimmunoassays in the sera of women with breast cancer and compared to those of control subjects. ER concentrations in breast tumor tissues were measured using 125I-radioreceptor assay.

RESULTS

Levels of T and prolactin showed a significant increase in both premenopausal and postmenopausal patients. E2 and P levels were significantly increased in follicular premenopausal and postmenopausal patients. Luteal E2 showed non-significant changes, whereas the luteal P level was significantly decreased. No significant alterations were found in the levels of serum LH, FSH, T3, T4 and TSH either in premenopausal or postmenopausal patients. Higher levels of ER were found in the tumors of postmenopausal than in those of premenopausal patients. A positive correlation was found between levels of ER and age of the patients (r = 0.35), whereas a negative correlation was observed between ER and serum E2 (r = -0.26).

CONCLUSIONS

This study provides evidence of an association between high levels of serum E2 and T and increased risk of breast cancer in postmenopausal women. Abnormalities in serum P and prolactin are probably associated with a breast cancer risk and ER may be considered as a biochemical marker for breast cancer development.

The serum protein profile of early parity which induces protection against breast cancer

Early parity reduces the risk of breast cancer in women while nulliparity and late parity increase the risk of breast cancer. In order to translate this protection to women where early pregnancy is not feasible, much work has focused on understanding how parity confers protection against breast cancer, the molecular mechanisms by which this occurs is still not well understood. Healthy parous and nulliparous women were recruited for this study. We assessed serum protein profiles of early parous, late parous, and nulliparous women using the Phospho Explorer antibody array. Significantly altered proteins identified were validated by Western blot analysis. In silico analysis was performed with the data obtained. Our findings indicate increased phosphorylation levels of CDK1, AKT1 and Epo-R increased cell cycle and cell proliferation in late/nulliparous women. Increased levels of LIMK1, paxillin, caveolin-1, and tyrosine hydroxylase in late/nulliparous women demonstrate enhanced cell stress while decreased activity of p-p53 and pRAD51 in late/nulliparous women indicates decreased apoptosis and increased genomic instability. Further, increased levels of pFAK, pCD3zeta, pSTAT5B, MAP3K8 in early parous women favor enhanced innate/adaptive immunity. Overall, we have identified a unique protein signature that is responsible for the decreased risk of breast cancer and these proteins can also serve as biomarkers to predict the risk of breast cancer.

Synergistic effect of malathion and estrogen on mammary gland carcinogenesis

Breast cancer is the most frequent malignancy diagnosed in women and is a classical model of hormone-dependent malignancy. Over the past 15-20 years, epidemiological studies have pointed to an increased breast cancer risk associated with prolonged exposure to female hormones. On the other hand, environmental chemicals such as malathion, an organophosphorous pesticide used to control a wide range of sucking and chewing pests of field crops, may be involved in the etiology of breast cancers. Results indicated that estrogen alone increased average number of lobules per mm2 of rat mammary glands in comparison to control and malathion alone at 30, 124, 240 and 400 days after 5-day treatments. On the other hand, malathion alone significantly increased the number of ducts in stage of proliferation at 10-240 days after 5-day treatments. Furthermore, markers for cancer detection such as mutant p53, c-myc, c-fos and CYPs proteins were overexpressed after treatments. Atropine, an anticholinergic drug, counteracted these effects when it was combined with malathion under similar conditions. The combination of malathion and estrogen synergistically increased number of lobules and ducts per mm2 of rat mammary glands after treatments and inducing mammary cancer. It can be concluded that combination of an environmental substance such as the pesticide malathion and an endogenous substance such as estrogen can enhance the deleterious effects in human mammary glands inducing cancer and atropine is able to diminish these effects.

Physical activity and sex hormone levels in estradiol- and placebo-treated postmenopausal women

OBJECTIVE

Postmenopausal changes in the hormonal milieu in women with or without hormone therapy are hypothesized to be the pathway for a number of menopause-associated modifications in physiology and disease risk. Physical activity may modify these changes in women's hormone profiles. The crucial yet complex relationship between physical activity and physiologic and pharmacologic sex hormone levels in postmenopausal women has not been investigated sufficiently.

METHODS

Using structured recall, physical activity was assessed longitudinally during a period of 2 years in 194 postmenopausal women (90 randomized to 1 mg 17β-estradiol treatment daily and 104 randomized to placebo) in the Estrogen in the Prevention of Atherosclerosis Trial. The levels of physical activity were correlated with the serum sex hormone and the serum hormone-binding globulin levels in each treatment group.

RESULTS

Among the placebo-treated women, total energy expenditure was positively associated with sex hormone-binding globulin (SHBG; P < 0.001) and inversely associated with testosterones (total, bioavailable, or free) and androstenedione (P < 0.001 for all), as well as with estradiol (P = 0.02). In estradiol-treated women, estradiol levels were inversely associated with total energy expenditure (P = 0.002) and weekly hours spent in moderate or more vigorous physical activity (P = 0.001).

CONCLUSIONS

Physical activity is associated with lower serum levels of estradiol in both hormone therapy-treated and untreated women. In placebo-treated women only, physical activity is associated with reduced androgen levels and elevated SHBG levels.

Nausea and vomiting after breast cancer surgery, and relationship with tumor receptor status

BACKGROUND

Breast surgery is associated with frequent post-operative nausea and vomiting (PONV). Studies have suggested that hormonal status affects PONV. Estrogen has been implicated in many emetic syndromes. Estrogen receptor (ER) and progesterone receptor (PR) status in breast tissue are hormonally affected. Kakugawa et al., in 2007, found a clear trend toward higher serum level of estrone, estradiol, and dehydroepiandrosterone sulfate in post menopausal women with PR-positive cancer.

PURPOSE

To investigate the possibility of an association between ER and/or PR status of breast tumor and incidence of PONV after breast cancer surgery.

METHODS

This observational study included 315 female patients undergoing major breast surgery. Relevant patient data, and intra-operative and postoperative details were noted. Incidence of PONV was noted using the PONV score. Patients were divided into two age groups: less than or equal to 50 years and more than 50 years of age. The ER and/or PR status of the patient was unknown to the investigator until the final analysis.

RESULTS

Use of the chi-squared test revealed no association between ER and/or PR and total PONV. Patients below 50 years had higher incidence of total PONV (p = 0.023). In patients above 50 years, the incidence of PONV was higher in the ER-positive group (p = 0.018).

CONCLUSION

The incidence of PONV is higher for patients below 50 years of age. The positive association between ER positivity and PONV in patients above 50 years of age could be attributed to the altered hormonal milieu in these patients and should be investigated further.

Hormone therapy and breast cancer risk

Hormone therapy (HT) is the most efficacious intervention for the relief of climacteric symptoms. Controversies surrounding HT have left many women puzzled and afraid. Gynecologists are faced with long-standing beneficial assumptions challenged by an abundance of robust detrimental new data, with little guidance on how to interpret these findings. Prescriptions for HT (and incidence of breast cancers in some areas) have fallen over the last 3 years due to anxiety provoked about breast cancer risk and recurrence. The current 'clinical climate' is against HT. Due to a lack of effective alternatives, women suffering from estrogen-deficiency symptoms are still requesting objective information about HT, particularly those at higher risk of breast cancer or those with a past history of breast cancer. In this situation, discussion of the current clinical uncertainty surrounding the use of HT must be undertaken to ensure that women are adequately informed. The objective of this presentation is to provide a framework for understanding breast cancer risk associated with HT. What are the precise molecular mechanisms of estrogen and progestin in the initiation of breast cancer? Does the risk of estrogen-only therapy on breast cancer vary by dose, constituent, route and duration of administration and cessation of use? Does HT, in addition to increasing risk for breast cancer, affect the type of breast cancer (lobular and ductal) diagnosed? Is HT associated with breast cancers that have better prognostic factors? How relevant are the changes in mammographic breast density associated with HT for the evaluation of breast cancer risk? What is the additional global health risk/benefit ratio associated with the selective use of progesterone or progestin that may confer a significant cardiovascular benefit, such as drospirenone? It is currently assumed and tested that new hormones with particular pharmacological profiles may ultimately achieve their therapeutic goal of relieving climacteric symptoms without an associated moderate increased risk of breast cancer.

Prolactin and breast cancer etiology: an epidemiologic perspective

A number of epidemiologic studies of prolactin and breast cancer etiology have recently become available. Retrospective case-control studies have suggested a modest positive or null relationship between circulating prolactin concentrations and risk of breast cancer. However these studies are limited by small sample sizes and the collection of blood after case diagnosis. Several large prospective studies, in which blood was collected prior to diagnosis, have observed modest positive associations between prolactin and risk. In a pooled analysis of approximately 80% of the world's prospective data, the relative risk (RR) comparing women in the top vs bottom quartile of prolactin levels was 1.3 (95% confidence interval (CI): 1.1, 1.6, p-trend = 0.002). The results were similar for premenopausal and postmenopausal women. Most notably, high prolactin levels were associated with a 60% increased risk of estrogen receptor (ER) positive tumors, but not with ER negative tumors. Limited genetic data suggest a role of polymorphisms in the prolactin and prolactin receptor genes in risk of breast cancer. Studies of survival have suggested that high pretreatment prolactin levels were associated with treatment failure, earlier recurrence, and worse overall survival. Parity and certain medications are the only confirmed factors associated with prolactin levels in women. Overall, epidemiologic data suggest that prolactin is involved in breast cancer etiology. Further research to better elucidate these associations and their underlying mechanisms is warranted.

Demonstration of adiponectin receptors 1 and 2 mRNA expression in human breast cancer cells

Recently, we have shown that low adiponectin levels are significantly associated with an increased breast cancer risk. It seems to be very important to study the expression of adiponectin receptor 1 (AdipoR1) and receptor 2 (AdipoR2) in the human breast epithelial cells and breast cancer cells in order to clarify whether or not adiponectin exerts its effects directly on these cells. Expression of adiponectin, AdipoR1, and AdipoR2 mRNA was determined by RT-PCR assay using the RNA samples obtained from human breast cancer cell lines (MCF-7, T47D, SKBR3, and MDA-MB231), HMEC (primary culture of normal human mammary epithelial cells), adipose tissues (axilla) as well as breast cancer cells and normal breast epithelial cells selectively collected from breast cancer tissues by laser microdissection (LMD). Adiponectin mRNA expression was observed only in the adipose tissues. On the other hand, AdipoR1 and AdipoR2 mRNA expression was observed in all four breast cancer cell lines, HMEC, adipose tissues as well as breast cancer cells and normal breast epithelial cells selectively collected by LMD. In addition, AdipoR1 and AdipoR2 expression in both normal breast epithelial cells and breast cancer cells was confirmed by immunohistochemistry. These results suggest a possibility that adiponectin might modulate the growth of normal breast epithelial cells and breast cancer cells directly through AdipoR1 and AdipoR2 receptors, and that the association of low serum adiponectin levels with a high breast cancer risk might be explained, at least in part, by the direct effect of adiponectin on the breast epithelial cells.

Aromatase inhibition: translation into a successful therapeutic approach

The development of the novel third-generation aromatase inhibitors and inactivators for breast cancer treatment is one of the most successful contemporary achievements in cancer therapy. Parallel to studies evaluating toxicity and clinical efficacy in metastatic disease, the endocrine effects of multiple compounds were evaluated, leading to the identification of the highly potent third-generation aromatase inhibitors based on estrogen deprivation and aromatase inhibition in vivo. Thus, translational studies have been of vital importance identifying the unique characteristics of these compounds. Whereas first- and second-generation aromatase inhibitors inhibit estrogen synthesis in vivo by up to 90%, the third-generation compounds anastrozole, exemestane, and letrozole were found to cause > or =98% aromatase inhibition. This article summarizes and discusses the "translational research" that provided the background for the implementation of the third-generation aromatase inhibitors and inactivators into large clinical trials. The need for future translational research exploiting the mechanisms of resistance to these compounds for future improvement of endocrine therapy is emphasized.

Development and potential clinical uses of human prolactin receptor antagonists

There is a large body of literature showing that prolactin (PRL) exerts growth-promoting activities in breast cancer, and possibly in prostate cancer and prostate hyperplasia. In addition, increasing evidence argues for the involvement of locally produced (autocrine) PRL, perhaps even more than pituitary-secreted (endocrine) PRL, in tumor growth. Because dopamine analogs are unable to inhibit PRL production in extrapituitary sites, alternative strategies need investigation. To that end, several PRL receptor antagonists have been developed by introducing various mutations into its natural ligands. For all but one of these analogs, the mechanism of action involves a competition with endogenous PRL for receptor binding. Such compounds are thus candidates to counteract the undesired actions of PRL, not only in tumors, but also in dopamine-resistant prolactinomas. In this review, we describe the different versions of antagonists that have been developed, with emphasis on the controversies regarding their characterization, and the limits for their potential development as a drug. The most recently developed antagonist, Delta1-9-G129R-hPRL, is the only one that is totally devoid of residual agonistic activity, meaning it acts as pure antagonist. We discuss to what extent this new molecule could be considered as a lead compound for inhibiting the actions of human PRL in the above-mentioned diseases. We also speculate on the multiple questions that could be addressed with respect to the therapeutic use of PRL receptor antagonists in patients.

A model to estimate the oestrogen receptor mediated effects from exposure to soy isoflavones in food

The advantages that regular consumption of a diet containing soy may have on human health have been enshrined in a major health claim that has been approved by the Food and Drug Administration in the USA, regarding potential protection from heart disease by soy. This could have a major influence on the dietary consumption patterns of soy for consumers and lead to the development of soy enriched foods to enable consumers to achieve the benefits thought to be associated with increased soy consumption in a Western diet. If an increase in soy consumption is beneficial to particular disease conditions, there is always the possibility that there will be effects other than those that are desirable. For soy-containing foods there has been concern that the phytoestrogen content of soy, which is composed of several isoflavones, could be a separate health issue, due to the oestrogen-like activity of isoflavones. To address this, a method has been developed to estimate, relative to 17-beta oestradiol, the activity of the common isoflavones present in soy phytoestrogens, based on their binding to and transcriptional activation of the major oestrogen receptor sub-types alpha and beta. Using this approach, the additional oestrogen-like activity that would be expected from inclusion of soy supplemented foodstuffs in a Western diet, can be determined for different sub-populations, who may have different susceptibilities to the potential for the unwanted biological effects occurring with consumption of soy enriched foods. Because of the theoretical nature of this model, and the controversy over the nature of whether some of the oestrogen-like effects of phytoestrogens are adverse, the biological effects of soy isoflavones and their potential for adverse effects in man, is also reviewed. The question that is critical to the long term safe use of foods enriched in soy is, which observed biological effects in animal studies are likely to also occur in man and whether these would have an adverse effect on human health.

Flaxseed consumption influences endogenous hormone concentrations in postmenopausal women

Lignans, similar in structure to endogenous sex steroid hormones, may act in vivo to alter hormone metabolism and subsequent cancer risk. The objective of this study was to examine effects of dietary intake of a lignan-rich plant food (flaxseed) on serum concentrations of endogenous hormones and binding proteins (estrone, estrone sulfate, 17 beta-estradiol, sex hormone-binding globulin, progesterone, prolactin, dehydroepiandrosterone sulfate, dehydroepiandrosterone, androstenedione, testosterone, and free testosterone) in postmenopausal women. This randomized, crossover trial consisted of three seven-week feeding periods, during which 28 postmenopausal women, aged 52-82 yr, consumed their habitual diets plus 0, 5, or 10 g of ground flaxseed. Serum samples collected during the last week of each feeding period were analyzed for serum hormones using standard diagnostic kits. The flaxseed diets significantly reduced serum concentrations of 17 beta-estradiol by 3.26 pg/ml (12.06 pmol/l) and estrone sulfate by 0.09 ng/ml (0.42 nmol/l) and increased prolactin by 1.92 micrograms/l (0.05 IU/ml). Serum concentrations of androstenedione, estrone, sex hormone-binding globulin, progesterone, testosterone, free testosterone, dehydroepiandrosterone, and dehydroepiandrosterone sulfate were not altered with flaxseed feeding. In this group of postmenopausal women, consuming flaxseed in addition to their habitual diets influenced their endogenous hormone metabolism by decreasing serum 17 beta-estradiol and estrone sulfate and increasing serum prolactin concentrations.

Bone mineral density and breast cancer risk in postmenopausal women

Two recent studies have shown a woman's bone mineral density (BMD) (a composite measure of exposure to many different factors throughout one's lifetime) predicts breast cancer. In a prospective cohort study, we examined whether hip BMD was associated with breast cancer risk among 8203 postmenopausal women. During an average follow-up of 3.7 years, 131 incident breast cancer cases (102 invasive) were identified. Cox proportional hazards models were used to obtain estimates of the relative risk of breast cancer. Our results demonstrate an increase in breast cancer risk among women with higher BMD. Independent of age, geographic area, and body mass index, relative to the lowest BMD quartile the risk of breast cancer (95% confidence interval) by increasing quartile was 1.9 (1.1, 3.2), 1.5 (0.8, 2.6), and 1.5 (0.8, 2.7), respectively. An examination of other factors important in determining BMD may help explain the positive association between BMD and breast cancer.

Association between estradiol, estrogen receptors, total lipids, triglycerides, and cholesterol in patients with benign and malignant breast tumors

This study addresses the correlation between the levels of estradiol (E2), total lipids, triglycerides, and cholesterol in serum and tissue samples of age-matched patients with benign (40 cases; 16 were premenopausal and 24 were postmenopausal) and malignant (50 cases; 17 were premenopausal and 33 were postmenopausal) breast tumors. Estradiol levels were determined in serum and cytosol, estrogen receptors (ER) were assayed in cytosol, and total lipids, triglycerides and cholesterol were determined in serum and membrane fractions of all benign and malignant breast disease patients. Serum E2 was significantly higher in malignant cases than benign ones (P<0.05) with a significant reduction (40%) in postmenopausal than premenopausal women. ER-positive tumors were significantly higher in postmenopausal women with malignant breast tumors than benign cases (P<0.05). Tissue levels of total lipids, triglycerides, and cholesterol were highly significantly increased in breast cancer women than women with benign breast diseases (P<0.05, P<0.005 and P<0.05 respectively) and they were also significantly correlated with estradiol levels. It could be concluded that the uptake of lipids from plasma by the tumor tissue is greatly correlated to estradiol and it may confirm the possible role of lipids as risk factor in breast cancer.

Is estradiol a genotoxic mutagenic carcinogen?

The natural hormone 17 beta-estradiol (E2) induces tumors in various organs of rats, mice, and hamsters. In humans, slightly elevated circulating estrogen levels caused either by increased endogenous hormone production or by therapeutic doses of estrogen medications increase breast or uterine cancer risk. Several epigenetic mechanisms of tumor induction by this hormone have been proposed based on its lack of mutagenic activity in bacterial and mammalian cell test systems. More recent evidence supports a dual role of estrogen in carcinogenesis as a hormone stimulating cell proliferation and as a procarcinogen inducing genetic damage. Tumors may be initiated by metabolic conversion of E2 to 4-hydroxyestradiol catalyzed by a specific 4-hydroxylase (CYP1B1) and by further activation of this catechol to reactive semiquinone/quinone intermediates. Several types of direct and indirect free radical-mediated DNA damage are induced by E2, 4-hydroxyestradiol, or its corresponding quinone in cell-free systems, in cells in culture, and/or in vivo. E2 also induces various chromosomal and genetic lesions including aneuploidy, chromosomal aberrations, gene amplification, and microsatellite instability in cells in culture and/or in vivo and gene mutations in several cell test systems. These data suggest that E2 is a weak carcinogen and weak mutagen capable of inducing genetic lesions with low frequency. Tumors may develop by hormone receptor-mediated proliferation of such damaged cells.

Plasma prolactin levels and subsequent risk of breast cancer in postmenopausal women

BACKGROUND

In animal studies, prolactin has been found to be important for mammary epithelial development and its administration has been shown consistently to increase the rate of mammary tumor formation. Previous epidemiologic studies of prolactin and breast cancer risk in postmenopausal women have been limited in size, and the results have been inconsistent. We conducted a nested case-control study within the prospective Nurses' Health Study cohort to better determine the relationship between plasma prolactin levels and postmenopausal breast cancer risk.

METHODS

Blood samples were collected from cohort members during the period from 1989 through 1990. Prolactin levels were measured by use of a microparticle enzyme immunoassay. Included in this analysis were 306 postmenopausal women who were diagnosed with breast cancer after blood donation but before June 1994. One or two postmenopausal control subjects were matched per case subject on the basis of age, postmenopausal hormone use, and time of day and month of blood collection; the study included a total of 448 control subjects.

RESULTS

In conditional logistic regression analyses, a significant positive association was observed between plasma level of prolactin and postmenopausal breast cancer risk (highest versus lowest quartile, multivariate relative risk = 2.03; 95% confidence interval = 1.24-3.31; two-sided P for trend = .01). The relationship was independent of plasma sex steroid hormone levels and was similar after excluding case subjects diagnosed in the first 2 years after blood collection.

CONCLUSIONS

These prospective data suggest that higher plasma prolactin levels are associated with an increased risk of breast cancer in postmenopausal women.

Relationship between the risk of breast cancer and physical activity. An epidemiological perspective

The possible protective effect of physical exercise on the risk of breast cancer has gained attention during the last few years. According to the current concepts of biological mechanisms underlying the possible protection, physical activity may alter menstrual function by reducing the number of ovulatory menstrual cycles via a hormone-related pathway and, thus, reducing the cumulative exposure to progesterone and estrogen. Experimental studies on the effects of exercise suggest changes in menstrual characteristics and in ovarian hormone serum levels. The majority of epidemiological studies, in spite of limitations in estimating physical activity and partly incomplete control of confounding factors, suggest a protective effect of physical activity. Whether physical activity offers a means of primary prevention of breast cancer is still an open issue.

Phyto-oestrogens and Western diseases

Incidences of breast, colorectal and prostate cancer are high in the Western world compared to countries in Asia. We have postulated that the Western diet compared to the semivegetarian diet in some Asian countries may alter hormone production, metabolism or action at the cellular level by some biochemical mechanisms. Our interest has been focused on two groups of hormone-like diphenolic phyto-oestrogens of dietary origin, the lignans and isoflavonoids abundant in plasma of subjects living in areas with low cancer incidence. The precursors of the biologically active compounds detected in man are found in soybean products, whole-grain cereal food, seeds, and berries. The plant lignan and isoflavonoid glycosides are converted by intestinal bacteria to hormone-like compounds. The weakly oestrogenic diphenols formed influence sex-hormone production, metabolism and biological activity, intracellular enzymes, protein synthesis, growth factor action, malignant cell proliferation, differentiation, cell adhesion and angiogenesis in such a way as to make them strong candidates for a role as natural cancer-protective compounds. Their effect on some of the most important steroid biosynthetic enzymes may result in beneficial modulation of hormone concentrations and action in the cells preventing development of cancer. Owing to their oestrogenic activity they reduce hot flushes and vaginal dryness in postmenopausal women and may to some degree inhibit osteoporosis, but alone they may be insufficient for complete protection. Soy intake prevents oxidation of the low-density lipoproteins in vitro when isolated from soy-treated individuals and affect favourably plasma lipid concentrations. Animal experiments provide evidence suggesting that both lignans and isoflavonoids may prevent the development of cancer as well as atherosclerosis. However, in some of these experiments it has not been possible to separate the phyto-oestrogen effect from the effect of other components in the food. The isoflavonoids and lignans may play a significant inhibitory role in cancer development particularly in the promotional phase of the disease, but recent evidence points also to a role in the initiation stage of carcinogenesis. At present, however, no definite recommendations can be made as to the dietary amounts needed for prevention of disease. This review deals with all the above-mentioned aspects of phyto-oestrogens.

Endogenous estrogens and breast cancer risk: the case for prospective cohort studies

It is generally agreed that estrogens, and possibly androgens, are important in the etiology of breast cancer, but no consensus exists as to the precise estrogenic or androgenic environment that characterizes risk, or the exogenous factors that influence the hormonal milieu. Nearly all the epidemiological studies conducted in the 1970s and 1980s were hospital-based case-control studies in which specimen sampling was performed well after the clinical appearance of the disease. Early prospective cohort studies also had limitations in their small sample sizes or short follow-up periods. However, more recent case-control studies nested within large cohorts, such as the New York University Women's Health Study and the Ormoni e Dieta nell'Eziologia dei Tumori study in Italy, are generating new data indicating that increased levels of estrone, estradiol and bioavailable estradiol, as well as their androgenic precursors, may be associated with a 4- to 6-fold increase in the risk of postmenopausal breast cancer. Further new evidence, which complements and expands the observations from the latter studies, shows that women with the thickest bone density, which may be a surrogate for cumulated exposure to hormones, experience severalfold increased risk of subsequent breast cancer as compared to women with thin bones. These data suggests that endogenous sex hormones are a key factor in the etiology of postmenopausal breast cancer. New prospective cohort studies should be conducted to examine the role of endogenous sex hormones in blood and urine samples obtained early in the natural history of breast cancer jointly with an assessment of bone density and of other important risk factors, such as mammographic density, physical activity, body weight, and markers of individual susceptibility, which may confer increased risk through an effect on the metabolism of endogenous hormones or through specific metabolic responses to Western lifestyle and diet.

A pilot study of urinary estrogen metabolites (16alpha-OHE1 and 2-OHE1) in postmenopausal women with and without breast cancer

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.

A prospective study of endogenous serum hormone concentrations and breast cancer risk in post-menopausal women on the island of Guernsey

The associations between serum concentrations of oestradiol, testosterone and sex hormone-binding globulin (SHBG) and risk of breast cancer in post-menopausal women were investigated in a prospective study on the island of Guernsey. Sixty-one women who developed breast cancer an average of 7.8 years after blood collection were matched for age, year of blood collection and number of years post-menopausal with 179 control subjects. Women using exogenous hormones at the time of blood collection were excluded from the study. Women who subsequently developed breast cancer had a 29% higher geometric mean oestradiol concentration than control women (P = 0.004). The odds ratio for breast cancer in the top third compared with the lowest third of the oestradiol concentration distribution was 5.03 (95% confidence interval 2.02-12.49, P for trend < 0.001). Adjusting for testosterone and SHBG concentrations did not substantially alter the odds ratio for oestradiol. Although testosterone and SHBG concentrations were associated with breast cancer risk, the concentrations of these hormones were correlated with those of oestradiol; the associations were not statistically significant after adjusting for oestradiol concentration. These data provide evidence that serum oestradiol concentrations in post-menopausal women may have a substantial effect on breast cancer risk.

A prospective study of urinary oestrogen excretion and breast cancer risk

To test the hypothesis that high levels of endogenous oestrogens increase the risk for developing breast cancer, concentrations of oestrone, oestradiol and oestriol were measured in 24 h urine samples from 1000 women participants in a prospective study of breast cancer on the island of Guernsey. Sixty-nine subjects were diagnosed with breast cancer subsequent to urine collection. Among women who were premenopausal at the time of urine collection, cases excreted less oestrogen than controls; the odds ratios (95% CI) for breast cancer in the middle and upper thirds of the distribution of oestrogen excretion, in comparison with the lower third (reference group, assigned odds ratio = 1.0), were 0.5(0.2-1.2) and 0.4(0.2-1.1) respectively for oestrone, 0.8(0.4-1.8 and 0.4(0.2-1.1) for oestradiol, 0.7(0.3-1.6) and 0.7(0.3-1.6) for oestriol and 0.9(0.4-2.0) and 0.5(0.2-1.3) for total oestrogens. Among women who were post-menopausal at the time of urine collection, the trend was in the opposite direction, with an increase in risk associated with increased oestrogen excretion; the odds ratios were 0.9(0.3-2.2) and 1.1(0.5-2.8) for oestrone, 0.8(0.3-2.3) and 1.9(0.8-4.6) for oestradiol, 1.5(0.6-3.9) and 1.8(0.7-4.6) for oestriol and 0.9(0.4-2.6) and 1.9(0.7-4.7) for total oestrogens. The trends of increasing risk with increasing oestrogen excretion among post-menopausal women were statistically significant for oestradiol (P = 0.022) and for total oestrogens (P = 0.016). We conclude that high levels of endogenous oestrogens in post-menopausal women are associated with increased breast cancer risk, but that the relationship of oestrogens in premenopausal women with risk is unclear.

Steroid Hormone Levels in Patients with Advanced Breast Cancer during Therapy with Droloxifene: A Pilot Study

Antiestrogens, particularly tamoxifen, are effective in the treatment of pre- and postmenopausal women suffering from all stages of breast cancer. Unfortunately, many patients become resistant to tamoxifen during therapy, which allows the tumor to progress. Thus, a preclinical recognition of tumor progression, i.e. by monitoring serum hormone levels, could be worthwhile. The serum levels of dehydroepiandrosterone sulfate and estradiol of postmenopausal women with advanced breast cancer treated by the new antiestrogen droloxifene were therefore checked. However, only non-significant changes in the hormone levels during droloxifene therapy were observed, and no relation was found between hormone levels and the course of the disease, success or exhaustion of droloxifene application, or development of tumor progression. Our data do not confirm earlier findings reported in the literature that measurement of hormones seems to be suitable for an early indication of tumor progression during an antiestrogen therapy before its clinical manifestation.

Perturbation of cell cycle kinetics in the mammary gland by stilbene estrogen, diethylstilbestrol (DES)

In the present study we have examined the effect of stilbene estrogen on the proliferative activity, cell cycle kinetics and the differentiation of the mammary gland of female Noble rats. The exposure of animals to stilbene estrogen (diethylstilbestrol) or natural estrogen (estrone) (10 micrograms/24 h) significantly increased proliferation in mammary epithelial cells. Both labeling index and growth fraction were increased by DES or estrone treatment. In addition, both stilbene and natural estrogen exposure altered cell cycle kinetics. Stilbene estrogen exposure to animals increased the conversion of mammary epithelial cells from G0 to G1 and G1 to S-phase cells by 8.3- and 8.5-fold, respectively, compared to that of control. Differentiation measured by the degree of lobular maturation revealed that the conversion of immature structures to mature structures was significantly increased by 2.4-fold in response to DES or estrone exposure compared to that of control. Perturbation of cell cycle is considered as a risk factor for the development of cancer. Changes in proliferation and cell cycle have been shown to lead to genetic instability, ultimately resulting in cell transformation. Our results indicated an increase in labeling index and growth fraction and a perturbation in cell cycle kinetics from DES or estrone exposure. Perturbation of cell cycle in response to stilbene estrogen exposure may produce adverse effects in the mammary glands of the Noble rats.

Steroid gradients across the cancerous breast: an index of altered steroid metabolism in breast cancer?

The concentrations of 17 beta-estradiol, estrone, testosterone (T), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulphate, androstenedione (A), cortisol and prolactin (PRL) were determined in the peripheral venous blood and in the lateral thoracic vein of 14 premenopausal and 34 postmenopausal women who underwent surgery for a breast carcinoma. The difference between the two blood samples, defined as concentration gradient across the cancerous breast, was calculated for all hormones. A significant peripheral-local concentration gradient was found for DHEA and A both in pre- and postmenopausal patients, whereas for T it was observed only in postmenopausal subjects. Furthermore, DHEA and A gradients were correlated to the presence of estrogen receptors as determined by a radioligand binding assay. An inverse relationship between DHEA gradient and the expression of estrogen receptors was observed in premenopausal women, whereas in postmenopausal patients an opposite, although not significant, trend was found. These results suggest that in the cancerous breast: (1) DHEA, A and T (the latter only in postmenopause) could be taken up from plasma, and thus there could be a storage of these steroids inside the breast tissue and/or perhaps some alterations in their local metabolism; (2) androgens could play a different role in breast carcinogenesis in relation to the estrogen circulating levels and to the expression of estrogen receptors.

Dietary fat affects plasma prolactin in female F344 rats under conditions of ether stress

The influence of amount and type of dietary fat on circulating concentrations of prolactin and estradiol-17 beta in female F344 rats from which blood was sampled by decapitation under ether anesthesia was compared with that in rats from which blood was collected without anesthesia. The animals were fed isonutrient (adjusted for differences in energy density) semipurified diets containing 5% or 20% (by weight) sunflower seed oil or lard. Blood was sampled by decapitation with or without standardized ether anesthesia during the afternoon of proestrus-estrus or the morning of metestrus-diestrus, as determined by examination of vaginal smears. Plasma hormone concentrations were measured by radioimmunoassay. Prolactin levels were lower during proestrus-estrus in rats fed a low-fat diet than in animals fed a high-fat diet, statistically independent of the type of dietary fat, but only when blood was sampled by decapitation under ether anesthesia [p = 0.0384, 2-way analysis of variance (ANOVA)]. No such difference was found in rats decapitated without anesthesia. This effect of amount of dietary fat on prolactin in proestrus-estrus animals anesthetized with ether was predominantly present in animals fed polyunsaturated fat (p < 0.05, 1-way ANOVA and Tukey's test) and was statistically not significant in rats fed saturated fat diets. During metestrus-diestrus, prolactin levels were significantly lower in animals fed a high-saturated fat diet than in those fed low-saturated fat, low-unsaturated fat, or high-unsaturated fat diets, independent of the blood sampling conditions (p < 0.05, 2-way ANOVA and Tukey's test). No consistent effects on estradiol-17 beta levels were found in type or amount of dietary fat or in presence or absence of ether anesthesia before decapitation. Growth, apparent digestibility of fat, and caloric intake were similar in all four dietary groups, but food consumption was higher and food conversion efficiency was lower in animals fed low-fat diets than in those fed high-fat diets. This study confirms the hypothesis that effects of dietary fat, particularly polyunsaturated fat, on circulating prolactin occur only during (ether) stress. Because stress is a frequent and normal phenomenon, this observation implies that the mammary glands of animals with a high dietary intake of polyunsaturated fat are frequently exposed to higher circulating prolactin concentrations than rats fed a low-fat diet, which may be a major mechanism by which dietary fat enhances rat mammary carcinogenesis.

Determination of estrogens in plasma by high-performance liquid chromatography after pre-column derivatization with 2-(4-carboxyphenyl)-5,6-dimethylbenzimidazole

A sensitive method for the determination of estrogens by high-performance liquid chromatography with fluorimetric detection was reported. The estrogens were derivatized with 2-(4-carboxyphenyl)-5,6-dimethylbenzimidazole to their esters in the presence of 4-piperidinopyridine and 1-isopropyl-3-(3-dimethylaminopropyl)carbodiimide perchlorate. The resulting esters were extracted with a Sep-Pak C18 plus cartridge, and then esters were separated on a Wakosil 5C18 column with water-methanol (10:90, v/v) as the mobile phase. The esters were detected by fluorimetric detection (excitation wavelength = 336 nm, emission wavelength = 440 nm). The within-day relative standards deviations (n = 6) for each estrogen (1.0 ng per 100 microliters of plasma) were 8.7-13.0%, and day-to-day relative standard deviations (n = 6) were 8.3-11.8%. The limits of detection for estrogens (estrone, estradiol, estriol, estetrol, ethynyl-estradiol, 2-hydroxyestradiol, 4-hydroxyestradiol) were 0.1-0.2 pg per 100 microliters of plasma (signal-to-noise ratio 3).

The pituitary gland in patients with breast carcinoma: a histologic and immunocytochemical study of 125 cases

Pituitary glands obtained at autopsy of 125 women with disseminated breast carcinoma were studied to determine whether pituitary prolactin cell abnormalities (hyperplasia or adenoma) might be involved in the pathogenesis of breast carcinoma. In addition, we studied 85 pituitary glands obtained from unselected, consecutive autopsies in women without breast carcinoma but who died of other diseases (control group). The frequency of lactotroph hyperplasia was slightly higher in patients with breast carcinoma than in the control group, but the difference was not statistically significant, nor were differences in the frequency and size of pituitary adenomas, prolactin-producing or otherwise. No correlation was found between the presence of lactotroph hyperplasia or prolactin-producing adenomas (or both) and such factors as the patient's age, bilaterality of the carcinoma, previous treatment with tamoxifen citrate or oophorectomy, stage of disease, or survival. The frequency of breast carcinoma metastatic to the pituitary gland was higher in the study group than in the control group; however, the difference was not statistically significant. No preferential site of metastatic involvement in the pituitary gland was noted. Relative proportions of other lesions such as infarcts, cysts, lymphocytic infiltrates, and basophilic invasion were similar in the study and control groups. This study indicates that accumulation of prolactin cells, whether hyperplastic or adenomatous, cannot be considered a major risk factor for the genesis or progression of breast carcinoma.

Serum oestrogen levels in postmenopausal women: comparison of American whites and Japanese in Japan

Serum oestrone (E1), oestradiol (E2) and sex hormone binding globulin (SHBG) levels were studied in postmenopausal Japanese women in Japan (n = 91) and postmenopausal American white women (n = 38). The Japanese women were deliberately chosen to be from a rural agricultural area in order to get samples which represent as closely as possible the traditional Japanese 'lifestyle' that gave rise to the low rates of breast cancer in Japan. E1 levels were 47%, and E2 levels 36%, greater in the American women; these differences were only reduced to 43% and 27% after adjustment for the lower weight of the Japanese. These results were all statistically highly significant. There was little difference in SHBG levels between the Japanese and the American women. These results for E1 and E2 could be an important part of the explanation why Japanese and American breast cancer rates continue to diverge further after the menopause.