Inflammation and increased aromatase expression occur in the breast tissue of obese women with breast cancer

Ghrelin and Breast Cancer: Emerging Roles in Obesity, Estrogen Regulation, and Cancer

Local and systemic factors have been shown to drive the growth of breast cancer cells in postmenopausal obese women, who have increased risk of estrogen receptor-positive breast cancer. Estrogens, produced locally in the breast fat by the enzyme aromatase, have an important role in promoting cancer cell proliferation. Ghrelin, a 28-amino acid peptide hormone, may also influence cancer growth. This peptide is produced in the stomach and acts centrally to regulate appetite and growth hormone release. Circulating levels of ghrelin, and its unacylated form, des-acyl ghrelin, are almost always inversely correlated with obesity, and these peptide hormones have recently been shown to inhibit adipose tissue aromatase expression. Ghrelin and des-acyl ghrelin have also been shown to be produced by some tumor cells and influence tumor growth. The ghrelin/des-acyl ghrelin–cancer axis is complex, one reason being that tumor cells have been shown to express splice variants of ghrelin, and ghrelin and des-acyl ghrelin might act at receptors other than the cognate ghrelin receptor, growth hormone secretagogue receptor 1a, in tumors. Effects of ghrelin and des-acyl ghrelin on energy homeostasis may also affect tumor development and growth. This review will summarize our current understanding of the role of ghrelin and des-acyl ghrelin in hormone-dependent cancers, breast cancer in particular.

Obesity-associated Breast Cancer: Analysis of risk factors

Several studies show that a significantly stronger association is obvious between increased body mass index (BMI) and higher breast cancer incidence. Furthermore, obese women are at higher risk of all-cause and breast cancer specific mortality when compared to non-obese women with breast cancer. In this context, increased levels of estrogens due to excessive aromatization activity of the adipose tissue, overexpression of pro-inflammatory cytokines, insulin resistance, hyperactivation of insulin-like growth factors (IGFs) pathways, adipocyte-derived adipokines, hypercholesterolemia and excessive oxidative stress contribute to the development of breast cancer in obese women. While higher breast cancer risk with hormone replacement therapy is particularly evident among lean women, in postmenopausal women who are not taking exogenous hormones, general obesity is a significant predictor for breast cancer. Moreover, increased plasma cholesterol leads to accelerated tumor formation and exacerbates their aggressiveness. In contrast to postmenopausal women, premenopausal women with high BMI are inversely associated with breast cancer risk. Nevertheless, life-style of women for breast cancer risk is regulated by avoiding the overweight and a high-fat diet. Estrogen-plus-progestin hormone therapy users for more than 5 years have elevated risks of both invasive ductal and lobular breast cancer. Additionally, these cases are more commonly node-positive and have a higher cancer-related mortality. Collectively, in this chapter, the impacts of obesity-related estrogen, cholesterol, saturated fatty acid, leptin and adiponectin concentrations, aromatase activity, leptin and insulin resistance on breast cancer patients are evaluated. Obesity-related prognostic factors of breast cancer also are discussed at molecular basis.

Obesity and breast cancer - what's new?

Obesity rates are increasing in the developed and developing world; this has implications for breast cancer risk and outcome. Areas covered: Recent advances relating to the association of obesity with breast cancer are reviewed. Expert commentary: Obesity has been associated with increased risk of postmenopausal hormone receptor positive and premenopausal triple negative breast cancer and with poor prognosis of most types of breast cancer. Obese individuals may present with breast cancer at a more advanced stage and their breast cancer may differ biologically from cancers diagnosed in nonobese women. A picture of a complex, multifactorial biology underlying the obesity-cancer link is emerging, with the identification of obesity-associated tissue and systemic changes that are cancer promoting, enhancing proliferation, invasion and metastasis. Intervention research to ascertain effects of weight loss and of pharmacologic interventions that reverse the metabolic changes of obesity is needed.

BET bromodomain proteins and epigenetic regulation of inflammation: implications for type 2 diabetes and breast cancer

Chronic inflammation drives pathologies associated with type 2 diabetes (T2D) and breast cancer. Obesity-driven inflammation may explain increased risk and mortality of breast cancer with T2D reported in the epidemiology literature. Therapeutic approaches to target inflammation in both T2D and cancer have so far fallen short of the expected improvements in disease pathogenesis or outcomes. The targeting of epigenetic regulators of cytokine transcription and cytokine signaling offers one promising, untapped approach to treating diseases driven by inflammation. Recent work has deeply implicated the Bromodomain and Extra-Terminal domain (BET) proteins, which are acetylated histone "readers", in epigenetic regulation of inflammation. This review focuses on inflammation associated with T2D and breast cancer, and the possibility of targeting BET proteins as an approach to regulating inflammation in the clinic. Understanding inflammation in the context of BET protein regulation may provide a basis for designing promising therapeutics for T2D and breast cancer.

Inflammation, dysregulated metabolism and aromatase in obesity and breast cancer

Obesity is associated with an increased risk of estrogen-dependent breast cancer after menopause. Adipose tissue undergoes important changes in obesity due to excess storage of lipids, leading to adipocyte cell death and the recruitment of macrophages. The resultant state of chronic low-grade inflammation is associated with the activation of NFkB signaling and elevated levels of aromatase, the rate-limiting enzyme in estrogen biosynthesis. This occurs not only in the visceral and subcutaneous fat, but also in the breast fat. The regulation of aromatase in the breast adipose stromal cell in response to inflammatory mediators is under the control of complex signaling pathways, including metabolic pathways involving LKB1/AMPK, p53, HIF1α and PKM2. Interventions aimed at modifying weight, including diet and exercise, are associated with changes in adipose tissue inflammation and estrogen production that are likely to impact breast cancer risk. This review will present an overview of these topics.

From obesity to cancer: a review on proposed mechanisms

Nowadays, obesity is considered as a serious and growing global health problem. It is documented that the overweight and obesity are major risk factors for a series of noncommunicable diseases, and in recent years, the obesity-cancer link has received much attention. Numerous epidemiological studies have shown that obesity is associated with increased risk of several cancer types, including colon, breast, endometrium, liver, kidney, esophagus, gastric, pancreatic, gallbladder, and leukemia, and can also lead to poorer treatment. We review here the epidemiological and experimental evidences for the association between obesity and cancer. Specifically, we discuss potential mechanisms focusing how dysfunctional angiogenesis, chronic inflammation, interaction of proinflammatory cytokines, endocrine hormones, and adipokines including leptin, adiponectin insulin, growth factors, estrogen, and progesterone and strikingly, cell metabolism alteration in obesity participate in tumor development and progression, resistance to chemotherapy, and targeted therapies such as antiangiogenic and immune therapies.

Obesity and Cancer Mechanisms: Tumor Microenvironment and Inflammation

Purpose There is growing evidence that inflammation is a central and reversible mechanism through which obesity promotes cancer risk and progression. Methods We review recent findings regarding obesity-associated alterations in the microenvironment and the local and systemic mechanisms through which these changes support tumor growth. Results Locally, hyperadiposity is associated with altered adipose tissue function, adipocyte death, and chronic low-grade inflammation. Most individuals who are obese harbor inflamed adipose tissue, which resembles chronically injured tissue, with immune cell infiltration and remodeling. Within this distinctly altered local environment, several pathophysiologic changes are found that may promote breast and other cancers. Consistently, adipose tissue inflammation is associated with a worse prognosis in patients with breast and tongue cancers. Systemically, the metabolic syndrome, including dyslipidemia and insulin resistance, occurs in the setting of adipose inflammation and operates in concert with local mechanisms to sustain the inflamed microenvironment and promote tumor growth. Importantly, adipose inflammation and its protumor consequences can be found in some individuals who are not considered to be obese or overweight by body mass index. Conclusion The tumor-promoting effects of obesity occur at the local level via adipose inflammation and associated alterations in the microenvironment, as well as systemically via circulating metabolic and inflammatory mediators associated with adipose inflammation. Accurately characterizing the obese state and identifying patients at increased risk for cancer development and progression will likely require more precise assessments than body mass index alone. Biomarkers of adipose tissue inflammation would help to identify high-risk populations. Moreover, adipose inflammation is a reversible process and represents a novel therapeutic target that warrants further study to break the obesity-cancer link.

White adipose tissue inflammation and cancer-specific survival in patients with squamous cell carcinoma of the oral tongue

BACKGROUND

Obesity is associated with increased adipose tissue in the tongue. Chronic white adipose tissue (WAT) inflammation commonly occurs in the obese. We investigated whether WAT inflammation in the tongue impacts survival in patients with squamous cell carcinoma (SCC) of the oral tongue.

METHODS

In a retrospective cohort study, patients with T1 and T2 SCC of the oral tongue who underwent curative-intent resection were included. Tongue WAT inflammation was defined by the presence of dead or dying adipocytes surrounded by macrophages forming crown-like structures. The primary and secondary endpoints were disease-specific survival (DSS) and overall survival (OS), respectively. Subgroup analyses were carried out in patients without lymph node involvement for whom adjuvant therapies were not indicated.

RESULTS

Archived tissue was available from 125 patients. The median follow-up was 55 months (range, 3-156 months). Overall, 49 of 125 patients (39%) had tongue WAT inflammation, which was associated with higher body mass index, increased tumor thickness, and vascular invasion (P < .05). The 3-year DSS rate for patients with tongue WAT inflammation was 59% (95% confidence interval [CI], 46%-76%) versus 82% (95% CI, 73%-92%) for those without inflammation. For patients without lymph node involvement for whom adjuvant therapy was not indicated (N = 70), tongue WAT inflammation was associated with shortened DSS and OS (P < .05). When adjusted for body mass index and potential prognostic covariates, the hazard ratio for DSS and OS was 5.40 (95% CI, 1.20-24.26) and 2.97 (95% CI, 1.02-8.65), respectively.

CONCLUSIONS

Tongue WAT inflammation is associated with worse DSS and OS in patients who have early stage SCC of the oral tongue. Cancer 2016;122:3794-3802. © 2016 American Cancer Society.

Metabolomics Analysis of Hormone-Responsive and Triple-Negative Breast Cancer Cell Responses to Paclitaxel Identify Key Metabolic Differences

To date, no targeted therapies are available to treat triple negative breast cancer (TNBC), while other breast cancer subtypes are responsive to current therapeutic treatment. Metabolomics was conducted to reveal differences in two hormone receptor-negative TNBC cell lines and two hormone receptor-positive Luminal A cell lines. Studies were conducted in the presence and absence of paclitaxel (Taxol). TNBC cell lines had higher levels of amino acids, branched-chain amino acids, nucleotides, and nucleotide sugars and lower levels of proliferation-related metabolites like choline compared with Luminal A cell lines. In the presence of paclitaxel, each cell line showed unique metabolic responses, with some similarities by type. For example, in the Luminal A cell lines, levels of lactate and creatine decreased while certain choline metabolites and myo-inositol increased with paclitaxel. In the TNBC cell lines levels of glutamine, glutamate, and glutathione increased, whereas lysine, proline, and valine decreased in the presence of drug. Profiling secreted inflammatory cytokines in the conditioned media demonstrated a greater response to paclitaxel in the hormone-positive Luminal cells compared with a secretion profile that suggested greater drug resistance in the TNBC cells. The most significant differences distinguishing the cell types based on pathway enrichment analyses were related to amino acid, lipid and carbohydrate metabolism pathways, whereas several biological pathways were differentiated between the cell lines following treatment.

Barriers to Obtaining Sera and Tissue Specimens of African-American Women for the Advancement of Cancer Research

African-American women, a historically understudied and underserved group, have increased risk for triple-negative breast cancer and obesity-associated disease. Obesity-associated metabolic diseases share a common link of low grade chronic inflammation, but not all obese women have metabolic disturbances or are inflamed. One goal of our ongoing research is to identify blood biomarkers that can predict increased risk of breast cancer in women who have obesity or metabolic dysfunction. However, vulnerable populations that stand to benefit most from advances in biomedical research are also underrepresented in research studies. The development of effective, novel approaches for cancer prevention and treatment will require significant basic medical research effort to establish the necessary evidence base in multiple populations. Work with vulnerable human subjects at a safety net hospital enabled us to comment on potential obstacles to obtaining serological and tissue specimens from African-American women. Here, we report some unexpected barriers to participation in our ongoing research study that might inform future efforts.

Reducing the Risk of Breast Cancer Recurrence: an Evaluation of the Effects and Mechanisms of Diet and Exercise

With recent medical advances in diagnosis and treatment, the increasing numbers of long-term survivors of breast cancer is considerable and has resulted in the expansion of scientific research to include examination of lifestyle modifications as means of prevention of recurrence, new breast cancer events, and mortality. The objective of this report is to review randomized controlled trials (RCTs) including diet and/or exercise interventions on breast cancer recurrence in women with a history of breast cancer as well as pertinent recent epidemiologic evidence. Implicated biologic mechanisms are discussed to elucidate the impact of diet and exercise on disease recurrence.

Breast cancers from black women exhibit higher numbers of immunosuppressive macrophages with proliferative activity and of crown-like structures associated with lower survival compared to non-black Latinas and Caucasians

Racial disparities in breast cancer incidence and outcome are a major health care challenge. Patients in the black race group more likely present with an early onset and more aggressive disease. The occurrence of high numbers of macrophages is associated with tumor progression and poor prognosis in solid malignancies. Macrophages are observed in adipose tissues surrounding dead adipocytes in "crown-like structures" (CLS). Here we investigated whether the numbers of CD163+ tumor-associated macrophages (TAMs) and/or CD163+ CLS are associated with patient survival and whether there are significant differences across blacks, non-black Latinas, and Caucasians. Our findings confirm that race is statistically significantly associated with the numbers of TAMs and CLS in breast cancer, and demonstrate that the highest numbers of CD163+ TAM/CLS are found in black breast cancer patients. Our results reveal that the density of CD206 (M2) macrophages is a significant predictor of progression-free survival univariately and is also significant after adjusting for race and for HER2, respectively. We examined whether the high numbers of TAMs detected in tumors from black women were associated with macrophage proliferation, using the Ki-67 nuclear proliferation marker. Our results reveal that TAMs actively divide when in contact with tumor cells. There is a higher ratio of proliferating macrophages in tumors from black patients. These findings suggest that interventions based on targeting TAMs may not only benefit breast cancer patients in general but also serve as an approach to remedy racial disparity resulting in better prognosis patients from minority racial groups.

Body mass index and risk of luminal, HER2-overexpressing, and triple negative breast cancer

Triple negative (TN, tumors that do not express estrogen receptor (ER), progesterone receptor (PR), or human epidermal growth factor receptor 2 (HER2)) and HER2-overexpressing (H2E, ER-/HER2+) tumors are two particularly aggressive subtypes of breast cancer. There is a lack of knowledge regarding the etiologies of these cancers and in particular how anthropometric factors are related to risk. We conducted a population-based case-case study consisting of 2659 women aged 20-69 years diagnosed with invasive breast cancer from 2004 to 2012. Four case groups defined based on joint ER/PR/HER2 status were included: TN, H2E, luminal A (ER+/HER2-), and luminal B (ER+/HER2+). Polytomous logistic regression was used to estimate odds ratios (ORs) and associated 95 % confidence intervals (CIs) where luminal A patients served as the reference group. Obese premenopausal women [body mass index (BMI) ≥30 kg/m(2)] had an 82 % (95 % CI 1.32-2.51) increased risk of TN breast cancer compared to women whose BMI <25 kg/m(2), and those in the highest weight quartile (quartiles were categorized based on the distribution among luminal A patients) had a 79 % (95 % CI 1.23-2.64) increased risk of TN disease compared to those in the lowest quartile. Among postmenopausal women obesity was associated with reduced risks of both TN (OR = 0.74, 95 % CI 0.54-1.00) and H2E (OR = 0.47, 95 % CI 0.32-0.69) cancers. Our results suggest obesity has divergent impacts on risk of aggressive subtypes of breast cancer in premenopausal versus postmenopausal women, which may contribute to the higher incidence rates of TN cancers observed among younger African American and Hispanic women.

Obesity-dependent changes in interstitial ECM mechanics promote breast tumorigenesis

Obesity and extracellular matrix (ECM) density are considered independent risk and prognostic factors for breast cancer. Whether they are functionally linked is uncertain. We investigated the hypothesis that obesity enhances local myofibroblast content in mammary adipose tissue and that these stromal changes increase malignant potential by enhancing interstitial ECM stiffness. Indeed, mammary fat of both diet- and genetically induced mouse models of obesity were enriched for myofibroblasts and stiffness-promoting ECM components. These differences were related to varied adipose stromal cell (ASC) characteristics because ASCs isolated from obese mice contained more myofibroblasts and deposited denser and stiffer ECMs relative to ASCs from lean control mice. Accordingly, decellularized matrices from obese ASCs stimulated mechanosignaling and thereby the malignant potential of breast cancer cells. Finally, the clinical relevance and translational potential of our findings were supported by analysis of patient specimens and the observation that caloric restriction in a mouse model reduces myofibroblast content in mammary fat. Collectively, these findings suggest that obesity-induced interstitial fibrosis promotes breast tumorigenesis by altering mammary ECM mechanics with important potential implications for anticancer therapies.

DNA defects, epigenetics, and gene expression in cancer-adjacent breast: a study from The Cancer Genome Atlas

Recurrence rates after breast-conserving therapy may depend on genomic characteristics of cancer-adjacent, benign-appearing tissue. Studies have not evaluated recurrence in association with multiple genomic characteristics of cancer-adjacent breast tissue. To estimate the prevalence of DNA defects and RNA expression subtypes in cancer-adjacent, benign-appearing breast tissue at least 2 cm from the tumor margin, cancer-adjacent, pathologically well-characterized, benign-appearing breast tissue specimens from The Cancer Genome Atlas project were analyzed for DNA sequence, copy-number variation, DNA methylation, messenger RNA (mRNA) sequence, and mRNA/microRNA expression. Additional samples were also analyzed by at least one of these genomic data types and associations between genomic characteristics of normal tissue and overall survival were assessed. Approximately 40% of cancer-adjacent, benign-appearing tissues harbored genomic defects in DNA copy number, sequence, methylation, or in RNA sequence, although these defects did not significantly predict 10-year overall survival. Two mRNA/microRNA expression phenotypes were observed, including an active mRNA subtype that was identified in 40% of samples. Controlling for tumor characteristics and the presence of genomic defects, this active subtype was associated with significantly worse 10-year survival among estrogen receptor (ER)-positive cases. This multi-platform analysis of breast cancer-adjacent samples produced genomic findings consistent with current surgical margin guidelines, and provides evidence that extratumoral RNA expression patterns in cancer-adjacent tissue predict overall survival among patients with ER-positive disease.

Systemic Correlates of White Adipose Tissue Inflammation in Early-Stage Breast Cancer

PURPOSE

Obesity, insulin resistance, and elevated levels of circulating proinflammatory mediators are associated with poorer prognosis in early-stage breast cancer. To investigate whether white adipose tissue (WAT) inflammation represents a potential unifying mechanism, we examined the relationship between breast WAT inflammation and the metabolic syndrome and its prognostic importance.

EXPERIMENTAL DESIGN

WAT inflammation was defined by the presence of dead/dying adipocytes surrounded by macrophages forming crown-like structures (CLS) of the breast. Two independent groups were examined in cross-sectional (cohort 1) and retrospective (cohort 2) studies. Cohort 1 included 100 women undergoing mastectomy for breast cancer risk reduction (n = 10) or treatment (n = 90). Metabolic syndrome-associated circulating factors were compared by CLS-B status. The association between CLS of the breast and the metabolic syndrome was validated in cohort 2, which included 127 women who developed metastatic breast cancer. Distant recurrence-free survival (dRFS) was compared by CLS-B status.

RESULTS

In cohorts 1 and 2, breast WAT inflammation was detected in 52 of 100 (52%) and 52 of 127 (41%) patients, respectively. Patients with breast WAT inflammation had elevated insulin, glucose, leptin, triglycerides, C-reactive protein, and IL6 and lower high-density lipoprotein cholesterol and adiponectin (P < 0.05) in cohort 1. In cohort 2, breast WAT inflammation was associated with hyperlipidemia, hypertension, and diabetes (P < 0.05). Compared with patients without breast WAT inflammation, the adjusted HR for dRFS was 1.83 (95% CI, 1.07-3.13) for patients with inflammation.

CONCLUSIONS

WAT inflammation, a clinically occult process, helps to explain the relationship between metabolic syndrome and worse breast cancer prognosis. Clin Cancer Res; 22(9); 2283-9. ©2015 AACR.

Obesity and Breast Cancer: A Complex Relationship

As prevalence of obesity continues to rise in the United States, we are beginning to elucidate the complex role of obesity-associated chronic inflammation, endocrine dysfunction, and hormone production as a driver for increased breast cancer risk. Epidemiological data suggest that obesity (BMI > 30) is associated with increased breast cancer incidence, worse prognosis, and higher mortality rates. Mechanistically, obesity and excess fat mass represent a state of chronic inflammation, insulin resistance, adipokine imbalance, and increased estrogen signaling. This pro-tumorigenic environment stimulates cancer development through abnormal growth, proliferation, and survival of mammary tissue. Importantly, obesity is a modifiable risk factor; alterations in cell proliferation, apoptosis, circulating estrogen, and insulin sensitivity are observed in response to weight loss attainable through behavior modification including dietary and exercise changes.

Lipoprotein subfractions by nuclear magnetic resonance are associated with tumor characteristics in breast cancer

Background

High-Density Lipoprotein (HDL)-cholesterol, has been associated with breast cancer development, but the association is under debate, and whether lipoprotein subfractions is associated with breast tumor characteristics remains unclear.

Methods

Among 56 women with newly diagnosed invasive breast cancer stage I/II, aged 35–75 years, pre-surgery overnight fasting serum concentrations of lipids were assessed, and body mass index (BMI) was measured. All breast tumors were immunohistochemically examined in the surgical specimen. Serum metabolomics of lipoprotein subfractions and their contents of cholesterol, free cholesterol, phospholipids, apolipoprotein-A1 and apolipoprotein-A2, were assessed using nuclear magnetic resonance. Principal component analysis, partial least square analysis, and uni- and multivariable linear regression models were used to study whether lipoprotein subfractions were associated with breast cancer tumor characteristics.

Results

The breast cancer patients had following means: age at diagnosis: 55.1 years; BMI: 25.1 kg/m²; total-Cholesterol: 5.74 mmol/L; HDL-Cholesterol: 1.78 mmol/L; Low-Density Lipoprotein (LDL)-Cholesterol: 3.45 mmol/L; triglycerides: 1.18 mmol/L. The mean tumor size was 16.4 mm, and the mean Ki67 hotspot index was 26.5 %. Most (93 %) of the patients had estrogen receptor (ER) positive tumors (≥1 % ER+), and 82 % had progesterone receptor (PgR) positive tumors (≥10 % PgR+). Several HDL subfraction contents were strongly associated with PgR expression: Apolipoprotein-A1 (β 0.46, CI 0.22–0.69, p < 0.001), HDL cholesterol (β 0.95, CI 0.51–1.39, p < 0.001), HDL free cholesterol (β 2.88, CI 1.28–4.48, p = 0.001), HDL phospholipids (β 0.70, CI 0.36–1.04, p < 0.001). Similar results were observed for the subfractions of HDL1-3. We observed inverse associations between HDL phospholipids and Ki67 (β -0.25, p = 0.008), and in particular between HDL1’s contents of cholesterol, phospholipids, apolipoprotein-A1, apolipoprotein-A2 and Ki67. No association was observed between lipoproteins and ER expression.

Conclusion

Our findings hypothesize associations between different lipoprotein subfractions, and PgR expression, and Ki 67 % in breast tumors. These findings may have clinical implications, but require confirmation in larger studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-016-0225-4) contains supplementary material, which is available to authorized users.

Inflammatory breast cancer: unique biological and therapeutic considerations

Through the concerted efforts of many patients, health-care providers, legislators, and other supporters, the past decade has seen the development of the first clinics dedicated to the care of patients with inflammatory breast cancer in the USA and other countries. Together with social networking, advocacy, and education, a few specialised centres have had substantial increases in patient numbers (in some cases ten times higher), which has further expanded the community of science and advocacy and increased the understanding of the disease process. Although inflammatory breast cancer is considered rare, constituting only 2-4% of breast cancer cases, poor prognosis means that patients with the disease account for roughly 10% of breast cancer mortality annually in the USA. I propose that the unique presentation of inflammatory breast cancer might require specific, identifiable changes in the breast parenchyma that occur before the tumour-initiating event. This would make the breast tissue itself a tumour-promoting medium that should be treated as a component of the pathology in multidisciplinary treatment and should be further studied for complementary targets to inhibit the pathobiology that is specific to inflammatory breast cancer.

Industry is not the dark side, but an essential partner to make progress in reproductive health

For the last 20 years, Thomas D'Hooghe has been coordinator of the Leuven University Fertility Center at Leuven University Hospitals, Belgium, one of the largest teaching hospitals in Europe. Since 1995, he has also been Professor of Reproductive Medicine and Biology at KU Leuven (University of Leuven) and Adjunct Professor at Yale University, USA. Since 1 October 2015, he has been the Vice President and Head of Global Medical Affairs Fertility at Merck's headquarters in Darmstadt, Germany. He has published nearly 300 papers in internationally peer-reviewed journals and has contributed to reproductive health serving major international organizations such as the WHO, the European Society of Human Reproduction and Embryology, the Society of Reproductive Investigation and the World Endometriosis Research Foundation.

Robust Early Inflammation of the Peripancreatic Visceral Adipose Tissue During Diet-Induced Obesity in the KrasG12D Model of Pancreatic Cancer

OBJECTIVES

Obesity increases the incidence of multiple types of cancer. Our previous work has shown that a high-fat, high-calorie diet (HFCD) leads to visceral obesity, pancreatic inflammation, and accelerated pancreatic neoplasia in KrasG12D (KC) mice. In this study, we aimed to investigate the effects of an HFCD on visceral adipose inflammation with emphasis on potential differences between distinct visceral adipose depots.

METHODS

We examined the weight and visceral obesity in both wild-type and KC mice on either control diet (CD) or HFCD. After 3 months, mice were killed for histological examination. Multiplex assays were also performed to obtain cytokine profiles between different adipose depots.

RESULTS

Both wild-type and KC mice on an HFCD exhibited significantly increased inflammation in the visceral adipose tissue, particularly in the peripancreatic fat (PPF), compared with animals on a CD. This was associated with significantly increased inflammation in the pancreas. Cytokine profiles were different between visceral adipose depots and between mice on the HFCD and CD.

CONCLUSIONS

Our results clearly demonstrate that an HFCD leads to obesity and inflammation in the visceral adipose tissue, particularly the PPF. These data suggest that obesity-associated inflammation in PPF may accelerate pancreatic neoplasia in KC mice.

Obesity and Breast Cancer: Molecular Interconnections and Potential Clinical Applications

Obesity is an important risk factor for breast cancer (BC) in postmenopausal women; interlinked molecular mechanisms might be involved in the pathogenesis. Increased levels of estrogens due to aromatization of the adipose tissue, inflammatory cytokines such as tumor necrosis factor-α, interleukin-6, and prostaglandin E2, insulin resistance and hyperactivation of insulin-like growth factors pathways, adipokines, and oxidative stress are all abnormally regulated in obese women and contribute to cancerogenesis. These molecular factors interfere with intracellular signaling in the mitogen-activated protein kinase and phosphatydilinositol-3-phosphate/mammalian target of rapamycin (mTOR) pathways, which regulate the progression of the cell cycle, apoptosis, and protein synthesis. In this context, structural defects of typical genes related to both BC and obesity, such as leptin, leptin receptor, serum paraoxonase/arylesterase 1, the fat mass and obesity-associated gene and melanocortin receptor 4, have been associated with a high or low risk of BC development. The early detection of these gene alterations might be useful as risk predictors in obese women, and targeting these pathways involved in the BC pathogenesis in obese women is a potential therapeutic tool. In particular, mTOR pathway deregulation concurs in both obesity and BC, and inhibition of this might disrupt the molecular interlinks in a similar manner to that of metformin, which exerts definite anticancer activity and is currently used as an antidiabetic drug with a weight-reducing property. The identification of both genetic and pharmacological implications on the prevention and management of BC is the ultimate aim of these studies.

IMPLICATIONS FOR PRACTICE

Obese women are at risk of breast cancer, but clinicians lack concrete tools for the prevention or early diagnosis of this risk. The present study, starting from the biology and the molecular defects characterizing both obesity and breast cancer, analyzed the potential molecules and genetic defects whose early identification could delineate a risk profile. Three steps are proposed that are potentially achievable in the clinical assessment of obese women, namely the evaluation of altered levels of serum molecules, the identification of genetic polymorphisms, and the study of the transcriptomic profile of premalignant lesions. Finally, the therapeutic implications of this molecular assessment were evaluated.

Noninvasive Detection of Inflammatory Changes in White Adipose Tissue by Label-Free Raman Spectroscopy

White adipose tissue inflammation (WATi) has been linked to the pathogenesis of obesity-related diseases, including type 2 diabetes, cardiovascular disease, and cancer. In addition to the obese, a substantial number of normal and overweight individuals harbor WATi, putting them at increased risk for disease. We report the first technique that has the potential to detect WATi noninvasively. Here, we used Raman spectroscopy to detect WATi with excellent accuracy in both murine and human tissues. This is a potentially significant advance over current histopathological techniques for the detection of WATi, which rely on tissue excision and, therefore, are not practical for assessing disease risk in the absence of other identifying factors. Importantly, we show that noninvasive Raman spectroscopy can diagnose WATi in mice. Taken together, these results demonstrate the potential of Raman spectroscopy to provide objective risk assessment for future cardiometabolic complications in both normal weight and overweight/obese individuals.

Epidemiological risk factors associated with inflammatory breast cancer subtypes

BACKGROUND

In this single-institution case-control study, we identified risk factors associated with inflammatory breast cancer (IBC) subtypes based on staining of estrogen receptor (ER), progesterone receptor (PR) and expression of human epidermal growth factor 2 (HER2neu) to determine distinct etiologic pathways.

METHODS

We identified 224 women with IBC and 396 cancer-free women seen at the MD Anderson Cancer Center. Multinomial logistic regression was used to estimate odds ratios (ORs) and 95 % confidence intervals (CIs) for associations between breast cancer risk factors and the IBC tumor subtypes: luminal (ER+ and/or PR+/HER2neu-), HER2neu+ (any ER and PR, HER2neu+), and triple-negative (ER-/PR-/HER2neu-).

RESULTS

In multivariable analysis, compared with women age ≥26 at first pregnancy, women age <26 had a higher risk of triple-negative IBC (OR 3.32, 95% CI 1.37-8.05). Women with a history of breast-feeding had a lower risk of triple-negative (OR 0.30; 95% CI 0.15-0.62) and luminal IBC (OR 0.35, 95% CI 0.18-0.68). A history of smoking was associated with an increased risk of luminal IBC (OR 2.37; 95% CI 1.24-4.52). Compared with normal-weight women, those who were overweight or obese (body mass index ≥25 kg/m(2)) had a higher risk of all three tumor subtypes (p < 0.01 for all subtypes).

CONCLUSION

Overweight or obese status is important modifiable risk factor for IBC of any subtype. Modifiable risk factors, age at first pregnancy (≥26), breast-feeding, and smoking may be associated with specific IBC subtypes. These results highlight the importance of evaluating epidemiologic risk factors for IBC for the identification of subtype-specific prevention strategies.

Tumor-associated macrophages: unwitting accomplices in breast cancer malignancy

Deleterious inflammation is a primary feature of breast cancer. Accumulating evidence demonstrates that macrophages, the most abundant leukocyte population in mammary tumors, have a critical role at each stage of cancer progression. Such tumor-associated macrophages facilitate neoplastic transformation, tumor immune evasion and the subsequent metastatic cascade. Herein, we discuss the dynamic process whereby molecular and cellular features of the tumor microenvironment act to license tissue-repair mechanisms of macrophages, fostering angiogenesis, metastasis and the support of cancer stem cells. We illustrate how tumors induce, then exploit trophic macrophages to subvert innate and adaptive immune responses capable of destroying malignant cells. Finally, we discuss compelling evidence from murine models of cancer and early clinical trials in support of macrophage-targeted intervention strategies with the potential to dramatically reduce breast cancer morbidity and mortality.

Obesity and Breast Cancer

The relationship between adiposity and breast cancer risk and prognosis is complex, with associations that differ depending on when body size is assessed (e.g., pre- vs. postmenopausal obesity) and when breast cancer is diagnosed (i.e., pre- vs. postmenopausal disease). Further, the impact of obesity on risk differs by tumor hormone receptor status (e.g., estrogen (ER) and progesterone (PR) receptor) and, among postmenopausal women, use of exogenous hormones (i.e., hormone replacement therapy (HRT)). In the context of these complexities, this review focuses on associations between childhood and adolescent adiposity, general adiposity, weight changes (i.e., loss and gain), abdominal adiposity, and breast cancer risk and survival. Finally, we discuss potential mechanisms linking adiposity to breast cancer.

Ovariectomy is associated with metabolic impairments and enhanced mammary tumor growth in MKR mice

Obesity and type 2 diabetes (T2D) are associated with an increased risk of breast cancer incidence and mortality. Common features of obesity and T2D are insulin resistance and hyperinsulinemia. A mammary tumor promoting effect of insulin resistance and hyperinsulinemia was demonstrated in the transgenic female MKR mouse model of pre-diabetes inoculated with mammary cancer cells. Interestingly, in MKR mice, as well as in other diabetic mouse models, males exhibit severe hyperglycemia, while females display insulin resistance and hyperinsulinemia with only a mild increase in blood glucose levels. This gender-specific protection from hyperglycemia may be attributed to estradiol, a key player in the regulation of the metabolic state, including obesity, glucose homeostasis, insulin resistance, and lipid profile. The aim of this study was to investigate the effects of ovariectomy (including the removal of endogenous estradiol) on the metabolic state of MKR female mice and subsequently on the growth of Mvt-1 mammary cancer cells, inoculated into the mammary fat pad of ovariectomized mice, compared with sham-operated mice. The results showed an increase in body weight, accompanied by increased fat mass, elevated blood glucose levels, and hypercholesterolemia, in ovariectomized MKR mice. In addition, mammary tumor growth was significantly higher in these mice. The results suggest that ovarian hormone deficiency may promote impaired metabolic homeostasis in the hyperinsulinemic MKR female mice, which in turn is associated with an increased growth of mammary tumors.

Obesity and Cancer: Concepts and Challenges

The rates of overweight and obesity are increasing worldwide in both developed and developing countries. Obesity is a major public health problem as it is associated with many diseases, including diabetes, hypertension, dyslipidemia, atherosclerosis, and some types of cancer. Breast cancer is a malignancy in which both the risk of development and the prognosis are negatively impacted by the obese state. The precise mechanisms pathophysiologically linking obesity and cancer are still under investigation. The biological basis for these associations includes both systemic and local tissue effects and white adipose tissue inflammation appears to be a critical component. A comprehensive understanding of the mechanisms linking obesity, inflammation and cancer may provide an opportunity for the development of strategies to attenuate the negative impact of obesity.

Obesity and inflammation: new insights into breast cancer development and progression

The importance of inflammation in promoting carcinogenesis and tumor progression is well recognized. Chronic inflammation caused by a variety of infectious agents can lead to the development of several common malignancies. Similarly, inflammatory bowel disease is a well-known risk factor for colorectal cancer. Much less is known about the link between inflammation and the development of breast cancer. Recent data suggest that obesity causes both in-breast and systemic inflammation that contribute to the development and progression of breast cancer. This observation has potentially important implications in terms of prevention and treatment of breast cancer, especially given the rising worldwide overweight and obesity rates. Inflamed white adipose tissue (WAT) within the breast is associated with elevated levels of proinflammatory mediators, enhanced expression of aromatase (the rate-limiting enzyme for estrogen biosynthesis), and increased estrogen receptor-α (ER-α)-dependent gene expression. Systemic consequences of obesity including altered adipokine levels, elevated circulating estrogen levels, and insulin resistance are also believed to play a role in the pathogenesis of breast cancer. Collectively, these findings suggest a significant role for inflammation in the pathogenesis of breast cancer in obese and overweight patients.

Obesity and inflammation: new insights into breast cancer development and progression

The importance of inflammation in promoting carcinogenesis and tumor progression is well recognized. Chronic inflammation caused by a variety of infectious agents can lead to the development of several common malignancies. Similarly, inflammatory bowel disease is a well-known risk factor for colorectal cancer. Much less is known about the link between inflammation and the development of breast cancer. Recent data suggest that obesity causes both in-breast and systemic inflammation that contribute to the development and progression of breast cancer. This observation has potentially important implications in terms of prevention and treatment of breast cancer, especially given the rising worldwide overweight and obesity rates. Inflamed white adipose tissue (WAT) within the breast is associated with elevated levels of proinflammatory mediators, enhanced expression of aromatase (the rate-limiting enzyme for estrogen biosynthesis), and increased estrogen receptor-α (ER-α)-dependent gene expression. Systemic consequences of obesity including altered adipokine levels, elevated circulating estrogen levels, and insulin resistance are also believed to play a role in the pathogenesis of breast cancer. Collectively, these findings suggest a significant role for inflammation in the pathogenesis of breast cancer in obese and overweight patients.

The Interactions of Obesity, Inflammation and Insulin Resistance in Breast Cancer

Obese postmenopausal women have an increased breast cancer risk, the principal mechanism for which is elevated estrogen production by adipose tissue; also, regardless of menstrual status and tumor estrogen dependence, obesity is associated with biologically aggressive breast cancers. Type 2 diabetes has a complex relationship with breast cancer risk and outcome; coexisting obesity may be a major factor, but insulin itself induces adipose aromatase activity and estrogen production and also directly stimulates breast cancer cell growth and invasion. Adipose tissue inflammation occurs frequently in obesity and type 2 diabetes, and proinflammatory cytokines and prostaglandin E2 produced by cyclooxygenase-2 in the associated infiltrating macrophages also induce elevated aromatase expression. In animal models, the same proinflammatory mediators, and the chemokine monocyte chemoattractant protein-1, also stimulate tumor cell proliferation and invasion directly and promote tumor-related angiogenesis. We postulate that chronic adipose tissue inflammation, rather than body mass index-defined obesity per se, is associated with an increased risk of type 2 diabetes and postmenopausal estrogen-dependent breast cancer. Also, notably before the menopause, obesity and type 2 diabetes, or perhaps the associated inflammation, promote estrogen-independent, notably triple-negative, breast cancer development, invasion and metastasis by mechanisms that may involve macrophage-secreted cytokines, adipokines and insulin.

Obesity and cancer: local and systemic mechanisms

Obesity is a leading modifiable risk factor for the development of several epithelial malignancies. In addition to increasing risk, obesity also confers worse prognosis for many cancers. Obesity represents an overall state of energy imbalance frequently associated with systemic effects including insulin resistance, altered hormone signaling, and high circulating levels of proinflammatory mediators. In addition to its systemic effects, obesity causes subclinical white adipose inflammation including increased tissue levels of proinflammatory mediators. Both local and systemic effects are likely to contribute to the development and progression of cancer. An understanding of the interplay between local and systemic alterations involved in the obesity-cancer link provides the basis for developing interventions aimed at mitigating the protumorigenic effects.

Targeting obesity-related adipose tissue dysfunction to prevent cancer development and progression

The incidence of obesity, a leading modifiable risk factor for common solid tumors, is increasing. Effective interventions are needed to minimize the public health implications of obesity. Although the mechanisms linking increased adiposity to malignancy are incompletely understood, growing evidence points to complex interactions among multiple systemic and tissue-specific pathways including inflamed white adipose tissue. The metabolic and inflammatory consequences of white adipose tissue dysfunction collectively provide a plausible explanation for the link between overweight/obesity and carcinogenesis. Gaining a better understanding of these underlying molecular pathways and developing risk assessment tools that identify at-risk populations will be critical in implementing effective and novel cancer prevention and management strategies.

Weight gain and inflammation regulate aromatase expression in male adipose tissue, as evidenced by reporter gene activity

Obesity and white adipose tissue (WAT) inflammation are associated with enhanced aromatization in women, but little is known about the regulation of aromatase (CYP19A1) gene expression in male WAT. We investigated the impact of weight gain and WAT inflammation on the regulation of CYP19A1 in males, by utilizing the hARO-Luc aromatase reporter mouse model containing a >100-kb 5'-region of the human CYP19A1 gene. We show that hARO-Luc reporter activity is enhanced in WAT of mice with increased adiposity and inflammation. Dexamethasone and TNFα, as well as forskolin and phorbol 12-myristate 13-acetate, upregulate hARO-Luc activity, suggesting the involvement of promoters I.4 and I.3/II. Furthermore, we show that diet enriched with antioxidative plant polyphenols attenuates WAT inflammation and hARO-Luc activity in obese males. In conclusion, our data suggest that obesity-associated WAT inflammation leads to increased peripheral CYP19A1 expression in males, and that polyphenol-enriched diet may have the potential to attenuate excessive aromatization in WAT of obese men.

Aromatase overexpression in dysfunctional adipose tissue links obesity to postmenopausal breast cancer

The number of breast cancer cases has increased in the last a few decades and this is believed to be associated with the increased prevalence of obesity worldwide. The risk of breast cancer increases with age beyond menopause and the relationship between obesity and the risk of breast cancer in postmenopausal women is well established. The majority of postmenopausal breast cancers are estrogen receptor (ER) positive and estrogens produced in the adipose tissue promotes tumor formation. Obesity results in the secretion of inflammatory factors that stimulate the expression of the aromatase enzyme, which converts androgens into estrogens in the adipose tissue. Evidence demonstrating a link between obesity and breast cancer has led to the investigation of metabolic pathways as novel regulators of estrogen production, including pathways that can be targeted to inhibit aromatase specifically within the breast. This review aims to present some of the key findings in this regard.

A nude mouse model of obesity to study the mechanisms of resistance to aromatase inhibitors

Obesity is a risk factor for breast cancer progression. Breast cancer patients who are overweight or obese or have excess abdominal fat have an increased risk of local or distant recurrence and cancer-related death. Hormone depletion therapies can also cause weight gain, exacerbating the risk for these patients. To understand the effect of obesity on hormone-dependent human breast cancer tumors, we fed ovariectomized athymic nude mice a diet containing 45% kcal fat and 17% kcal sucrose (high fat sucrose diet (HFSD)), 10% kcal fat (low fat diet (LFD)), or a standard chow diet (chow). The mice fed the HFSD developed metabolic abnormalities consistent with the development of obesity such as weight gain, high fasting blood glucose, and impaired glucose tolerance. These mice also developed hyperinsulinemia and insulin resistance. The obese mice also had a higher tumor growth rate compared to the lean mice. Furthermore, the obese mice showed a significantly reduced responsiveness to letrozole. To understand the role of obesity in this reduced responsiveness, we examined the effect of insulin on the growth of MCF-7Ca cells in response to estrogen or letrozole. The presence of insulin rendered MCF-7Ca cells less responsive to estrogen and letrozole. Exogenous insulin treatment of MCF-7Ca cells also resulted in increased p-Akt as well as ligand-independent phosphorylation of ERα. These findings suggest that diet-induced obesity may result in reduced responsiveness of tumors to letrozole due to the development of hyperinsulinemia. We conclude that obesity influences the response and resistance of breast cancer tumors to aromatase inhibitor treatment.

Overweight, Obesity, and Postmenopausal Invasive Breast Cancer Risk: A Secondary Analysis of the Women's Health Initiative Randomized Clinical Trials

IMPORTANCE

More than two-thirds of US women are overweight or obese, placing them at increased risk for postmenopausal breast cancer.

OBJECTIVE

To investigate in this secondary analysis the associations of overweight and obesity with risk of postmenopausal invasive breast cancer after extended follow-up in the Women's Health Initiative (WHI) clinical trials.

DESIGN, SETTING, AND PARTICIPANTS

The WHI clinical trial protocol incorporated measured height and weight, baseline and annual or biennial mammography, and adjudicated breast cancer end points in 67 142 postmenopausal women ages 50 to 79 years at 40 US clinical centers. The women were enrolled from 1993 to 1998 with a median of 13 years of follow-up through 2010; 3388 invasive breast cancers were observed.

MAIN OUTCOMES AND MEASURES

Height and weight were measured at baseline, and weight was measured annually thereafter. Data were collected on demographic characteristics, personal and family medical history, and personal habits (smoking, physical activity). Women underwent annual or biennial mammograms. Breast cancers were verified by medical records reviewed by physician adjudicators.

RESULTS

Women who were overweight and obese had an increased invasive breast cancer risk vs women of normal weight. Risk was greatest for obesity grade 2 plus 3 (body mass index [BMI], calculated as weight in kilograms divided by height in meters squared, >35.0) (hazard ratio [HR] for invasive breast cancer, 1.58; 95% CI, 1.40-1.79). A BMI of 35.0 or higher was strongly associated with risk for estrogen receptor-positive and progesterone receptor-positive breast cancers (HR, 1.86; 95% CI, 1.60-2.17) but was not associated with estrogen receptor-negative cancers. Obesity grade 2 plus 3 was also associated with advanced disease, including larger tumor size (HR, 2.12; 95% CI, 1.67-2.69; P = .02), positive lymph nodes (HR, 1.89; 95% CI, 1.46-2.45; P = .06), regional and/or distant stage (HR, 1.94; 95% CI, 1.52-2.47; P = .05), and deaths after breast cancer (HR, 2.11; 95% CI, 1.57-2.84; P < .001). Women with a baseline BMI of less than 25.0 who gained more than 5% of body weight over the follow-up period had an increased breast cancer risk (HR, 1.36; 95% CI, 1.1-1.65), but among women already overweight or obese we found no association of weight change (gain or loss) with breast cancer during follow-up. There was no effect modification of the BMI-breast cancer relationship by postmenopausal hormone therapy, and the direction of association across BMI categories was similar for never, past, and current hormone therapy use.

CONCLUSIONS AND RELEVANCE

Obesity is associated with increased invasive breast cancer risk in postmenopausal women. These clinically meaningful findings should motivate programs for obesity prevention.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00000611.

Obesity, proinflammatory mediators, adipose tissue progenitors, and breast cancer

PURPOSE OF REVIEW

There is emerging evidence that obesity is associated with an increase in the incidence, severity, and mortality from different types of cancer, including postmenopausal breast cancer. Here, we discuss the role of white adipose tissue (WAT) cells and of related soluble factors in the local and metastatic growth of this neoplastic disease. Moreover, we discuss the recent increase in the use of WAT-derived progenitor cells in breast cancer patients to enhance the quality of breast reconstruction and the related risks.

RECENT FINDINGS

In several murine models, WAT cells and progenitors were found to have cooperative roles in promoting local breast cancer. Moreover, they were found to contribute to adipocytes and pericytes supporting the cancer vasculature, and stimulated the metastatic progression of breast cancer. There are some clinically retrospective data showing a significant increase in the frequency of intraepithelial neoplasia in patients who received a lipofilling procedure for breast reconstruction compared with controls.

SUMMARY

Preclinical models and clinical studies are urgently needed to investigate how to inhibit the tumor-promoting activity of WAT cells and progenitors. The risks associated with the use of WAT cells for breast reconstructions should be better investigated retrospectively and prospectively.

Emerging roles for IL-11 signaling in cancer development and progression: Focus on breast cancer

Interleukin (IL)-11 is a member of the IL-6 family of cytokines that is defined by the shared use of the GP130 signal transducing receptor subunit. In addition of its long recognized activities as a hemopoietic growth factor, IL-11 has an emerging role in epithelial cancer biology. Through the activation of the GP130-Janus kinase signaling cascade and associated transcription factor STAT3, IL-11 can confer many of the tumor intrinsic 'hallmark' capabilities to neoplastic cells, if they express the ligand-specific IL-11Rα receptor subunit. Accordingly, IL-11 signaling has recently been identified as a rate-limiting step for the growth tumors arising from the mucosa of the gastrointestinal tract. However, there is less appreciation for a potential role of IL-11 to support breast cancer progression, apart from its well documented capacity to facilitate bone metastasis. Here we review evidence that IL-11 expression in breast cancer correlates with poor disease outcome and discuss some of the molecular mechanisms that are likely to underpin these observations. These include the capacity of IL-11 to stimulate survival and proliferation of cancer cells alongside angiogenesis of the primary tumor and of metastatic progenies at distant organs. We review current strategies to interfere with IL-11 signaling and advocate that inhibition of IL-11 signaling may represent an emerging therapeutic opportunity for numerous cancers.

Cell-Based High-Throughput Screening for Aromatase Inhibitors in the Tox21 10K Library

Multiple mechanisms exist for endocrine disruption; one nonreceptor-mediated mechanism is via effects on aromatase, an enzyme critical for maintaining the normal in vivo balance of androgens and estrogens. We adapted the AroER tri-screen 96-well assay to 1536-well format to identify potential aromatase inhibitors (AIs) in the U.S. Tox21 10K compound library. In this assay, screening with compound alone identifies estrogen receptor alpha (ERα) agonists, screening in the presence of testosterone (T) identifies AIs and/or ERα antagonists, and screening in the presence of 17β-estradiol (E2) identifies ERα antagonists. Screening the Tox-21 library in the presence of T resulted in finding 302 potential AIs. These compounds, along with 31 known AI actives and inactives, were rescreened using all 3 assay formats. Of the 333 compounds tested, 113 (34%; 63 actives, 50 marginal actives) were considered to be potential AIs independent of cytotoxicity and ER antagonism activity. Structure-activity analysis suggested the presence of both conventional (eg, 1, 2, 4, - triazole class) and novel AI structures. Due to their novel structures, 14 of the 63 potential AI actives, including both drugs and fungicides, were selected for confirmation in the biochemical tritiated water-release aromatase assay. Ten compounds were active in the assay; the remaining 4 were only active in high-throughput screen assay, but with low efficacy. To further characterize these 10 novel AIs, we investigated their binding characteristics. The AroER tri-screen, in high-throughput format, accurately and efficiently identified chemicals in a large and diverse chemical library that selectively interact with aromatase.

Relationships of sex steroid hormone levels in benign and cancerous breast tissue and blood: A critical appraisal of current science

A systematic review of the literature on sex steroid measurement in breast tissue identified only 19 articles meeting the following criteria: menopausal status given; steroids measured in tissue homogenates by conventional RIA with a purification step or by mass spectrometry; and values reported per g tissue or per g protein. Twelve articles were analyzed in detail for: ratios of sex steroid hormone levels in cancerous or benign tissues to blood levels, stratified by menopausal status; ratios between the different hormone levels within tissues or within blood; and difference in these ratios between tissue and blood compartments. Estrogen and androgen concentrations varied greatly in benign and cancerous tissues and in blood between individuals. Postmenopausal, but not premenopausal, estradiol concentrations were significantly higher in cancerous compared to benign breast tissue. The estradiol/estrone ratio was lowest in premenopausal benign tissue, and substantially higher in premenopausal cancerous tissue and postmenopausal benign and cancerous tissues. Estradiol and estrone levels were considerably higher in tissue than in plasma in both premenopausal and postmenopausal women. Androgen levels were generally higher in the benign than the cancerous tissue, and tissue androgen levels were higher than in plasma, suggesting in situ aromatization of androgens to estrogens in breast cancer tissue. Limited available data on levels of hydroxylated estrogens in breast tissue compared to corresponding levels in plasma or urine were reviewed, but due to the paucity of studies no conclusions can presently be drawn regarding the relationship of the 2-hydroxyestrone:16α-hydroxyestrone ratio to breast cancer risk and genotoxic effects of 4-hydroxylated estrogens. Finally, data on hormone levels in breast adipose tissue were analyzed; high levels of androstenedione and testosterone and significant estrone and estradiol levels in breast adipocytes from postmenopausal breast cancer patients are consistent with an obesity-inflammation-aromatase axis occurring locally in breast tissue. The controversies regarding the source of intratumoral estrogens in the breast are summarized.

High-Fat, High-Calorie Diet Enhances Mammary Carcinogenesis and Local Inflammation in MMTV-PyMT Mouse Model of Breast Cancer

Epidemiological studies provide strong evidence that obesity and the associated adipose tissue inflammation are risk factors for breast cancer; however, the molecular mechanisms are poorly understood. We evaluated the effect of a high-fat/high-calorie diet on mammary carcinogenesis in the immunocompetent MMTV-PyMT murine model. Four-week old female mice (20/group) were randomized to receive either a high-fat (HF; 60% kcal as fat) or a low-fat (LF; 16% kcal) diet for eight weeks. Body weights were determined, and tumor volumes measured by ultrasound, each week. At necropsy, the tumors and abdominal visceral fat were weighed and plasma collected. The primary mammary tumors, adjacent mammary fat, and lungs were preserved for histological and immunohistochemical examination and quantification of infiltrating macrophages, crown-like structure (CLS) formation, and microvessel density. The body weight gains, visceral fat weights, the primary mammary tumor growth rates and terminal weights, were all significantly greater in the HF-fed mice. Adipose tissue inflammation in the HF group was indicated by hepatic steatosis, pronounced macrophage infiltration and CLS formation, and elevations in plasma monocyte chemoattractant protein-1 (MCP-1), leptin and proinflammatory cytokine concentrations. HF intake was also associated with higher tumor-associated microvascular density and the proangiogenic factor MCP-1. This study provides preclinical evidence in a spontaneous model of breast cancer that mammary adipose tissue inflammation induced by diet, enhances the recruitment of macrophages and increases tumor vascular density suggesting a role for obesity in creating a microenvironment favorable for angiogenesis in the progression of breast cancer.

High mammographic density is associated with an increase in stromal collagen and immune cells within the mammary epithelium

INTRODUCTION

Mammographic density (MD), after adjustment for a women's age and body mass index, is a strong and independent risk factor for breast cancer (BC). Although the BC risk attributable to increased MD is significant in healthy women, the biological basis of high mammographic density (HMD) causation and how it raises BC risk remain elusive. We assessed the histological and immunohistochemical differences between matched HMD and low mammographic density (LMD) breast tissues from healthy women to define which cell features may mediate the increased MD and MD-associated BC risk.

METHODS

Tissues were obtained between 2008 and 2013 from 41 women undergoing prophylactic mastectomy because of their high BC risk profile. Tissue slices resected from the mastectomy specimens were X-rayed, then HMD and LMD regions were dissected based on radiological appearance. The histological composition, aromatase immunoreactivity, hormone receptor status and proliferation status were assessed, as were collagen amount and orientation, epithelial subsets and immune cell status.

RESULTS

HMD tissue had a significantly greater proportion of stroma, collagen and epithelium, as well as less fat, than LMD tissue did. Second harmonic generation imaging demonstrated more organised stromal collagen in HMD tissues than in LMD tissues. There was significantly more aromatase immunoreactivity in both the stromal and glandular regions of HMD tissues than in those regions of LMD tissues, although no significant differences in levels of oestrogen receptor, progesterone receptor or Ki-67 expression were detected. The number of macrophages within the epithelium or stroma did not change; however, HMD stroma exhibited less CD206(+) alternatively activated macrophages. Epithelial cell maturation was not altered in HMD samples, and no evidence of epithelial-mesenchymal transition was seen; however, there was a significant increase in vimentin(+)/CD45(+) immune cells within the epithelial layer in HMD tissues.

CONCLUSIONS

We confirmed increased proportions of stroma and epithelium, increased aromatase activity and no changes in hormone receptor or Ki-67 marker status in HMD tissue. The HMD region showed increased collagen deposition and organisation as well as decreased alternatively activated macrophages in the stroma. The HMD epithelium may be a site for local inflammation, as we observed a significant increase in CD45(+)/vimentin(+) immune cells in this area.