Body weight and postmenopausal breast cancer risk defined by estrogen and progesterone receptor status among Swedish women: A prospective cohort study

Trends in the incidence and survival of women with hormone receptor-positive breast cancer from 1990 to 2019: a large population-based analysis

Hormone receptor-positive breast cancer (BC) is the most prevalent subtype of BC and is generally correlated with a favorable prognosis. This study aimed to determine the incidence and survival trends among women diagnosed with hormone receptor-positive BC between 1990 and 2019. Female patients with hormone receptor-positive BC for calendar years 1990-2019 were obtained from the Surveillance, Epidemiology, and End Results (SEER) database and categorized into six diagnostic groups according to the year of diagnosis. Age-adjusted incidence rates (IRs) were calculated using joinpoint regression. We used the Kaplan-Meier method and multivariate Cox regression analyses to determine the association between diagnostic groups, and overall survival (OS) and BC-specific survival (BCSS). The final analysis included 370,729 women, among whom 37,943 (10.2%), 49,266 (13.3%), 55,652 (15.0%), 64,451 (17.4%), 77,127 (20.8%), and 86,290 (23.3%) were diagnosed between 1990 and 1994, 1995-1999, 2000-2004, 2005-2009, 2010-2014, and 2015-2019, respectively. Within the overall cohort, IRs gradually increased from 70 per 100,000 in 1990 to 113 per 100,000 in 2019 (average annual percent change, 1.59%; 95% CI, 1.18-1.99). Multivariate Cox regression analysis revealed that the survival outcomes gradually improved over nearly three decades among hormone receptor-positive BC patients, with a 0.8% and 1.3% decrease in risk for all-cause and BC-specific mortality each year, respectively. Compared to 1990-1994, hormone receptor-positive BC patients diagnosed in 2015-2019 had a 22% lower risk of all-cause death (hazard ratio [HR], 0.78; 95% CI, 0.76-0.81) and a 27% lower risk of BC-specific death (HR, 0.73; 95% CI, 0.70-0.76). The development of treatment strategies within the past three decades, especially endocrine therapy, may contribute to the continuous improvement of clinical outcomes in patients with hormone receptor-positive BC.

Implications of obesity and insulin resistance for the treatment of oestrogen receptor-positive breast cancer

Breast cancer is the most common cancer in women, and incidence rates are rising, it is thought in part, due to increasing levels of obesity. Endocrine therapy (ET) remains the cornerstone of systemic therapy for early and advanced oestrogen receptor-positive (ER + ) breast cancer, but despite treatment advances, it is becoming more evident that obesity and insulin resistance are associated with worse outcomes. Here, we describe the current understanding of the relationship between both obesity and diabetes and the prevalence and outcomes for ER+ breast cancer. We also discuss the mechanisms associated with resistance to ET and the relationship to treatment toxicity.

Associations of breast cancer etiologic factors with stromal microenvironment of primary invasive breast cancers in the Ghana Breast Health Study

Background

Emerging data suggest that beyond the neoplastic parenchyma, the stromal microenvironment (SME) impacts tumor biology, including aggressiveness, metastatic potential, and response to treatment. However, the epidemiological determinants of SME biology remain poorly understood, more so among women of African ancestry who are disproportionately affected by aggressive breast cancer phenotypes.

Methods

Within the Ghana Breast Health Study, a population-based case-control study in Ghana, we applied high-accuracy machine-learning algorithms to characterize biologically-relevant SME phenotypes, including tumor-stroma ratio (TSR (%); a metric of connective tissue stroma to tumor ratio) and tumor-associated stromal cellular density (Ta-SCD (%); a tissue biomarker that is reminiscent of chronic inflammation and wound repair response in breast cancer), on digitized H&E-stained sections from 792 breast cancer patients aged 17-84 years. Kruskal-Wallis tests and multivariable linear regression models were used to test associations between established breast cancer risk factors, tumor characteristics, and SME phenotypes.

Results

Decreasing TSR and increasing Ta-SCD were strongly associated with aggressive, mostly high grade tumors (p-value < 0.001). Several etiologic factors were associated with Ta-SCD, but not TSR. Compared with nulliparous women [mean (standard deviation) = 28.9% (7.1%)], parous women [mean (standard deviation) = 31.3% (7.6%)] had statistically significantly higher levels of Ta-SCD (p-value = 0.01). Similarly, women with a positive family history of breast cancer [FHBC; mean (standard deviation) = 33.0% (7.5%)] had higher levels of Ta-SCD than those with no FHBC [mean (standard deviation) = 30.9% (7.6%); p-value = 0.01]. Conversely, increasing body size was associated with decreasing Ta-SCD [mean (standard deviation) = 32.0% (7.4%), 31.3% (7.3%), and 29.0% (8.0%) for slight, moderate, and large body sizes, respectively, p-value = 0.005]. These associations persisted and remained statistically significantly associated with Ta-SCD in mutually-adjusted multivariable linear regression models (p-value < 0.05). With the exception of body size, which was differentially associated with Ta-SCD by grade levels (p-heterogeneity = 0.04), associations between risk factors and Ta-SCD were not modified by tumor characteristics.

Conclusions

Our findings raise the possibility that epidemiological factors may act via the SME to impact both risk and biology of breast cancers in this population, underscoring the need for more population-based research into the role of SME in multi-state breast carcinogenesis.

Trends in Breast Cancer Incidence and Mortality in the United States From 2004-2018: A Surveillance, Epidemiology, and End Results (SEER)-Based Study

The incidence and mortality data for patients with breast cancer in the United States are important to healthcare administrators for planning healthcare measures such as screening mammograms. In this study, we examined breast cancer incidence and incidence-based mortality in the United States from 2004-2018 using the Surveillance, Epidemiology, and End Results (SEER) database. We reviewed 915,417 cases of breast cancer diagnosed between 2004 and 2018. Overall, the data showed an increased incidence rate of breast cancer among all races and a decreased mortality rate among all races. Breast cancer incidence rates increased by 0.3% (95% CI, 0.1, 0.4, p<0.001) per year over the study period. Breast cancer incidence rates increased for all age, race, and stage groups except for stage regional, which showed a statistically significant decrease in the incidence of -0.9% (95% CI, -1.1, -0.7, p<0.001). The highest decrease in mortality was observed among white patients, with an overall statistically significant decrease in rates by -14.3% (95% CI, -18.1, -10.4, p <0.001). The highest decrease in rates was observed between 2016 and 2018: -48.6 (95% CI, -52.6, -44.3, p <0.001). In black/African American patients, the overall incidence-based mortality decreased by -11.6% (95% CI -15.9, -7.1 p <.001), with the highest decrease in rates observed between 2016 and 2018 with a decrease of -51.3% (95% CI -56.6, -45.3, p <0.001). In Hispanic Americans, the overall incidence-based mortality decreased by -12.3% (95% CI -16.9, -7.4, p <.001), which is lower than in white Americans.

Obesity and breast cancer

The paper presents an analysis of the latest literature data on the problem of obesity and breast cancer (BC). This review presents modern approaches to the diagnosis of BC in obese patients, new molecular methods of breast imaging,  analyzes the features of the course of BC with obesity depending on menstrual status, molecular biological subtypes of the tumor, the mechanisms of the development of BC against the background of obesity.

Rat Mammary carcinoma susceptibility 3 (Mcs3) pleiotropy, socioenvironmental interaction, and comparative genomics with orthologous human 15q25.1-25.2

Genome-wide association studies of breast cancer susceptibility have revealed risk-associated genetic variants and nominated candidate genes; however, the identification of causal variants and genes is often undetermined by genome-wide association studies. Comparative genomics, utilizing Rattus norvegicus strains differing in susceptibility to mammary tumor development, is a complimentary approach to identify breast cancer susceptibility genes. Mammary carcinoma susceptibility 3 (Mcs3) is a Copenhagen (COP/NHsd) allele that confers resistance to mammary carcinomas when introgressed into a mammary carcinoma susceptible Wistar Furth (WF/NHsd) genome. Here, Mcs3 was positionally mapped to a 7.2-Mb region of RNO1 spanning rs8149408 to rs107402736 (chr1:143700228-150929594, build 6.0/rn6) using WF.COP congenic strains and 7,12-dimethylbenz(a)anthracene-induced mammary carcinogenesis. Male and female WF.COP-Mcs3 rats had significantly lower body mass compared to the Wistar Furth strain. The effect on female body mass was observed only when females were raised in the absence of males indicating a socioenvironmental interaction. Furthermore, female WF.COP-Mcs3 rats, raised in the absence of males, did not develop enhanced lobuloalveolar morphologies compared to those observed in the Wistar Furth strain. Human 15q25.1-25.2 was determined to be orthologous to rat Mcs3 (chr15:80005820-82285404 and chr15:83134545-84130720, build GRCh38/hg38). A public database search of 15q25.1-25.2 revealed genome-wide significant and nominally significant associations for body mass traits and breast cancer risk. These results support the existence of a breast cancer risk-associated allele at human 15q25.1-25.2 and warrant ultrafine mapping of rat Mcs3 and human 15q25.1-25.2 to discover novel causal genes and variants.

Postmenopausal overweight and breast cancer risk; results from the KARMA cohort

Purpose

To study the risk of incident breast cancer and subtype-specific breast cancer in relation to excess body weight in a contemporary Swedish prospective cohort study, The Karolinska Mammography Project for Risk Prediction of Breast Cancer, KARMA.

Methods

A total of 35,412 postmenopausal women attending mammography and included in the KARMA study provided baseline data on body mass index (BMI) and potential confounders. During eight years of follow-up, 822 incident invasive breast cancer cases were identified.

Results

Women with overweight (BMI ≥ 25–< 30 kg/m²) constituting 34% of the study cohort had an increased risk of incident breast cancer with an adjusted Hazard Ratio (HR_adj) 1.19 (95% CI 1.01–1.4). A similar, however, non-significant, association was found for women with obesity (BMI ≥ 30 kg/m²) conferring 13% of the cohort, with a HR_adj of 1.19 (95% CI 0.94–1.5). Overweight was associated with risk of node-negative disease (HR_adj 1.29, 95% CI 1.06–1.58), whereas obesity was associated with node-positive disease (HR_adj 1.64, 95% CI 1.09–2.48). Both overweight and obesity were associated with risk of estrogen receptor positive (ER+) disease (HR_adj 1.20, 95% CI 1.00–1.44 and HR_adj 1.33, 95% CI 1.03–1.71, respectively), and low-grade tumors (HR_adj 1.25, 95% CI 1.02–1.54, and HR_adj 1.40, 95% CI 1.05–1.86, respectively). Finally, obesity was associated with ER+HER2 negative disease (HR_adj 1.37, 95% CI 1.05–1.78) and similarly luminal A tumors (HR_adj 1.43, 95% CI 1.02–2.01).

Conclusion

Overweight and obesity are associated with an increased risk of developing breast cancer, specifically ER+, low-grade, and for obesity, node-positive, high-risk breast cancer indicating a further need for risk communication and preventive programs.

Obesity and Breast Cancer Risk: The Oncogenic Implications of Metabolic Dysregulation

CONTEXT

Breast cancer is increasing in prevalence in parallel with rising rates of obesity worldwide. Obesity is recognized as a leading modifiable risk factor for the development of breast cancer; however, this association varies considerably by clinicopathologic features, and the underlying mechanisms are complex.

EVIDENCE ACQUISITION

Pubmed literature search using combinations of "obesity," "breast cancer risk," "diet," "exercise," "weight gain," "weight loss," "adipose tissue inflammation," "crown-like structure," "immune markers," "metformin," "gliflozins," "SGLT-2i," "GLP1-RA," and related terms.

EVIDENCE SYNTHESIS

Elevated body mass index and weight gain are associated with increased risk of postmenopausal, hormone receptor-positive breast cancer. Emerging evidence suggests that adverse measures of body composition in individuals of any weight can also confer increased breast cancer risk. Mechanistically, various factors including altered adipokine balance, dysfunctional adipose tissue, dysregulated insulin signaling, and chronic inflammation contribute to tumorigenesis. Weight loss and more specifically fat mass loss through lifestyle and pharmacologic interventions improve serum metabolic and inflammatory markers, sex hormone levels, and measures of breast density, suggesting a link to decreased breast cancer risk.

CONCLUSION

Incorporating markers of metabolic health and body composition measures with body mass index can capture breast cancer risk more comprehensively. Further studies of interventions targeting body fat levels are needed to curb the growing prevalence of obesity-related cancer.

Associations of Computed Tomography Image-Assessed Adiposity and Skeletal Muscles with Triple-Negative Breast Cancer

Obesity measured by anthropometrics is associated with increased risk of triple-negative breast cancer (TNBC). It is unclear to what extent specific adipose tissue components, aside from muscle, are associated with TNBC. This retrospective study included 350 breast cancer patients who received treatment between October 2011 and April 2020 with archived abdominal or pelvic computed tomography (CT) images. We measured the areas of adipose tissue and five-density levels of skeletal muscle on patients' third lumbar vertebra (L3) image. Logistic regression was performed to examine the associations of specific adiposity and skeletal muscles components and a four-category body composition phenotype with the TNBC subtype. Results showed that higher vs. lower areas (3rd vs. 1st tertiles) of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were associated with increased odds of TNBC vs. non-TNBC after adjusting for age, race, stage, tumor grade, tumor size, and skeletal muscle areas (adjusted odds ratio [AOR], 11.25 [95% CI = 3.46-36.52]) and (AOR, 10.34 [95% CI = 2.90-36.90]) respectively. Higher areas of low density muscle was also associated with increased odds of TNBC (AOR, 3.15 [95% CI = 1.05-10.98]). Compared to normal body composition (low adipose tissue/high muscle), high adiposity/high muscle was associated with higher odds of TNBC (AOR, 5.54 [95% CI = 2.12-14.7]). These associations were mainly in premenopausal women and among patients with the CT performed after breast cancer surgery. Specific adipose tissue and low-density muscle can be associated with the TNBC subtype in breast cancer patients. The direction of association warrants confirmation by prospective studies.

Association between body mass index and clinical characteristics, as well as with management, in Chinese patients with breast cancer

OBJECTIVE

Body mass index (BMI) is a risk factor associated with breast cancer in postmenopausal women. This study aimed to identify the associations of BMI with clinical characteristics and management of breast cancer in female Chinese patients.

METHODS

Clinicopathological information on 1296 women who were diagnosed with breast cancer was collected at our hospital. We recorded the clinicopathological characteristics, molecular phenotypes, manner of diagnosis, implementation rate of preoperative examinations, and surgical method used.

RESULTS

Significant differences were found in the tumor size, disease stage, manner of diagnosis, implementation rate of preoperative examinations, and the surgical method among different BMI groups. In premenopausal patients, significant differences were found in the distribution of molecular phenotypes and surgical approach among different BMI groups. In postmenopausal patients, different BMI groups showed significant differences in the tumor size, disease stage, distribution of molecular phenotypes, manner of diagnosis, rate of implementation of preoperative mammography, and surgical method.

CONCLUSION

Higher BMI is associated with a larger tumor size, more advanced disease stage, diagnosis by physical examination, higher implementation rate of preoperative examinations, and lower radical surgery rate in Chinese women with breast cancer. However, the relationship between BMI and molecular phenotypes differs between pre- and postmenopausal women.

Weight Regain and Breast Cancer-Related Biomarkers Following an Exercise Intervention in Postmenopausal Women

BACKGROUND

Epidemiologic studies have reported associations between weight fluctuations and postmenopausal breast cancer risk; however, the biological markers involved in this association are unknown. This study aimed to explore the associations between breast cancer-related biomarkers and weight regain following exercise-induced weight loss.

METHODS

From the 400 participants included in the Breast Cancer and Exercise Trial in Alberta, a total of 214 lost weight during the intervention and had follow-up blood samples, body composition, and covariate measurements. Outcomes were measured at baseline, 12 months (end of the study), and 24 months (follow-up).

RESULTS

During follow-up, weight regain was 1.80 kg [95% confidence interval (CI): -0.40-3.90], and was significantly associated with increases in estradiol [treatment effect ratio (TER) = 1.03; 95% CI, 1.01-1.04], estrone (TER = 1.02; 95% CI, 1.01-1.03), free estradiol (TER = 1.04; 95% CI, 1.02-1.05), the homeostatic model assessment for insulin resistance (TER = 1.03; 95% CI, 1.02-1.05), and insulin (TER = 1.03; 95% CI, 1.01-1.04), and decreases in sex hormone-binding globulin (SHBG; TER = 0.98; 95% CI, 0.97-0.99) levels. Nonstatistically significant associations were found for glucose and C-reactive protein. Furthermore, a statistically significant linear trend of increasing levels for all biomarkers, and decreasing SHBG, across weight regain categories was found.

CONCLUSIONS

These results suggest that weight regain following exercise-induced weight loss is associated with breast cancer-related biomarker changes in postmenopausal women.

IMPACT

These findings provide evidence to support the importance of developing effective strategies to prevent weight regain and, consequently, decrease postmenopausal breast cancer risk via changes in adiposity-related biomarkers.

Molecular insights into the interplay between adiposity, breast cancer and bone metastasis

Cancer is a complex disease, with various pre-existing health ailments enhancing its pathology. In cancer, the extracellular environment contains various intrinsic physiological factors whose levels are altered with aging and pre-existing conditions. In obesity, the tumor microenvironment and metastases are enriched with factors that are both derived locally, and from other physiological compartments. Similarly, in obesity, the cancer cell environment both at the site of origin and at the secondary site i.e., metastatic niche, contains significantly more phenotypically-altered adipocytes than that of un-obese cancer patients. Indeed, obesity has been linked with cancer progression, metastasis, and therapy resistance. Adipocytes not only interact with tumor cells, but also with adjacent stromal cells at primary and metastatic sites. This review emphasizes the importance of bidirectional interactions between adipocytes and breast tumor cells in breast cancer progression and its bone metastases. This paper not only chronicles the role of various adipocyte-derived factors in tumor growth, but also describes the significance of adipocyte-derived bone metastatic factors in the development of bone metastasis of breast cancer. It provides a molecular view of the interplay between the adipocytes and tumor cells involved in breast cancer bone metastasis. However, more research is needed to determine if targeting cancer-associated adipocytes holds promise as a potential therapeutic approach for breast cancer bone metastasis treatment. Interplay between adipocytes and breast cancer cells at primary cancer site and metastatic bone microenvironment. AMSC Adipose-derived mesenchymal stem cell, CAA Cancer associated adipocytes, CAF Cancer associated fibroblast, BMSC Bone marrow derived mesenchymal stem cell, BMA Bone marrow adipocyte.

Body size and weight change over adulthood and risk of breast cancer by menopausal and hormone receptor status: a pooled analysis of 20 prospective cohort studies

Associations between anthropometric factors and breast cancer (BC) risk have varied inconsistently by estrogen and/or progesterone receptor (ER/PR) status. Associations between prediagnostic anthropometric factors and risk of premenopausal and postmenopausal BC overall and ER/PR status subtypes were investigated in a pooled analysis of 20 prospective cohorts, including 36,297 BC cases among 1,061,915 women, using multivariable Cox regression analyses, controlling for reproductive factors, diet and other risk factors. We estimated dose-response relationships and tested for nonlinear associations using restricted cubic splines. Height showed positive, linear associations for premenopausal and postmenopausal BC risk (6-7% RR increase per 5 cm increment), with stronger associations for receptor-positive subtypes. Body mass index (BMI) at cohort baseline was strongly inversely associated with premenopausal BC risk, and strongly positively-and nonlinearly-associated with postmenopausal BC (especially among women who never used hormone replacement therapy). This was primarily observed for receptor-positive subtypes. Early adult BMI (at 18-20 years) showed inverse, linear associations for premenopausal and postmenopausal BC risk (21% and 11% RR decrease per 5 kg/m2, respectively) with stronger associations for receptor-negative subtypes. Adult weight gain since 18-20 years was positively associated with postmenopausal BC risk, stronger for receptor-positive subtypes, and among women who were leaner in early adulthood. Women heavier in early adulthood generally had reduced premenopausal BC risk, independent of later weight gain. Positive associations between height, baseline (adult) BMI, adult weight gain and postmenopausal BC risk were substantially stronger for hormone receptor-positive versus negative subtypes. Premenopausal BC risk was positively associated with height, but inversely with baseline BMI and weight gain (mostly in receptor-positive subtypes). Inverse associations with early adult BMI seemed stronger in receptor-negative subtypes of premenopausal and postmenopausal BC.

B-Comet Assay (Comet Assay on Buccal Cells) for the Evaluation of Primary DNA Damage in Human Biomonitoring Studies

Many subjects perceive venous blood collection as too invasive, and thus moving to better-accepted procedures for leukocytes collection might be crucial in human biomonitoring studies (e.g., biomonitoring of occupational or residential exposure to genotoxins) management. In this context, primary DNA damage was assessed in buccal lymphocytes (BLs), fresh whole venous, and capillary blood leukocytes, and compared with that in peripheral blood lymphocytes (PBLs)—the most frequently used cells—in 15 young subjects. Mouthwashes were collected after the volunteers rinsed their mouths with normal saline, and BLs were isolated by density gradient centrifugation. Blood samples were collected by venipuncture or by lancet. Anthropometric and lifestyle information was obtained by the administration of a structured questionnaire. As shown in the Bland-Altman plots, the level of agreement between BLs and PBLs lied within the accepted range, we thus enrolled a wider population (n = 54) to assess baseline DNA damage in BLs. In these cells, mean values of tail length (µm), tail intensity (%), and tail moment were 25.7 ± 0.9, 6.7 ± 0.4 and 1.0 ± 0.1, respectively. No significant association was observed between sex and smoking habit with any of the DNA damage parameters. Conversely, underweight subjects displayed significantly higher genomic instability compared with normal weight group (p < 0.05). In conclusion, we successfully managed to set up and update a non-invasive and well-accepted procedure for the isolation of BLs from saliva that could be useful in upcoming biomonitoring studies.

The association of body mass index and adverse clinicopathological characteristics in non-metastatic breast cancer

Background

Obesity is a global health problem. It is becoming increasingly prevalent in Saudi Arabia. High body mass index (BMI) is a risk factor for many diseases, including cancer. Noticeably, breast cancer (BC) cases in Saudi Arabia occur at a younger age than in western countries. Different lifestyle behaviors such as maintaining healthy body weight and physical activity may play a role in this. In this study, we investigated the association between BMI and BC adverse clinicopathological features.

Methods

This retrospective study was conducted by reviewing the records of women with non-metastatic BC over 4 years. The association between BMI and patients' demographics, BC histological type, receptor status, differentiation grade, tumor size, involvement of axillary lymph nodes, and performed procedures were analyzed.

Result

315 patients with non-metastatic BC were studied. The mean age at the time of diagnosis was 52.43 years ± 11.63. The mean BMI was 30.21 ± 5.77. The mean tumor size was 3.19 cm ± 3.52. The mean age of diagnosis is significantly higher in obese women than in other BMI groups (P = 0.025). Obese female patients aged ≥40 were more likely to present with larger tumor (P = 0.022) and numerically higher pathological axillary lymph nodes, trending toward statistical significance (P = 0.092).

Conclusion

The relationship between BMI and developing more aggressive BC is still not clear; in this study, we found that obese patients presented at an older age, with larger tumor and more pathologic lymph nodes. Further research to understand the impact of this finding on outcomes is warranted.

Microbial Alterations and Risk Factors of Breast Cancer: Connections and Mechanistic Insights

Breast cancer-related mortality remains high worldwide, despite tremendous advances in diagnostics and therapeutics; hence, the quest for better strategies for disease management, as well as the identification of modifiable risk factors, continues. With recent leaps in genomic technologies, microbiota have emerged as major players in most cancers, including breast cancer. Interestingly, microbial alterations have been observed with some of the established risk factors of breast cancer, such as obesity, aging and periodontal disease. Higher levels of estrogen, a risk factor for breast cancer that cross-talks with other risk factors such as alcohol intake, obesity, parity, breastfeeding, early menarche and late menopause, are also modulated by microbial dysbiosis. In this review, we discuss the association between known breast cancer risk factors and altered microbiota. An important question related to microbial dysbiosis and cancer is the underlying mechanisms by which alterations in microbiota can support cancer progression. To this end, we review the involvement of microbial metabolites as effector molecules, the modulation of the metabolism of xenobiotics, the induction of systemic immune modulation, and altered responses to therapy owing to microbial dysbiosis. Given the association of breast cancer risk factors with microbial dysbiosis and the multitude of mechanisms altered by dysbiotic microbiota, an impaired microbiome is, in itself, an important risk factor.

The Many Faces of Obesity and Its Influence on Breast Cancer Risk

Obesity is associated with increased risk of breast and other cancers. However, the complexity of the underlying mechanisms, together with the interplay of diet and physical activity—contributing to energy balance—and the role of adipose tissue, pose challenges to our understanding of the basis of this increased risk. Epidemiologic studies have documented a higher obesity prevalence in US black women compared to white women. Elucidation of the contribution of potential biological differences among racially distinct groups to their differences in breast cancer (BC) risk and mortality have been topics of considerable interest in recent years. The racial and ethnic variation in body fat distribution may account for at least part of the differences in breast cancer rates in these populations. Yet, while black women exhibit higher rates of obesity compared to white women, this does not translate directly into higher rates of BC. In fact, overall, BC in black women occurs with a lower incidence than BC in white women. Obesity is a known risk factor for postmenopausal breast cancer, and growing evidence suggests that abdominal obesity, also known as central obesity, may increase risk for triple negative breast cancer, which is more common in premenopausal women. The positive association of postmenopausal BC risk and specifically estrogen receptor (ER)-positive BC, is presumably due largely to accumulation of estrogen in the adipose tissue of the breast and other tissues. Of the two main types of adipose tissue—subcutaneous and visceral—visceral adipocytes are more active metabolically. Such adipose tissue harbors multiple molecular entities that promote carcinogenesis: endocrine molecules/hormones, immunologic factors, inflammatory cytokines, metabolic alterations, and other components of the microenvironment. Expression of these culpable entities is largely regulated by epigenetic mechanisms. The interrelationship between these entities and drivers of epigenetic alteration are critical to the regulation of pathways connecting obesity and cancer risk. Initiatives to counteract the carcinogenic effects of obesity have primarily involved modulation of energy balance by diet. However, targeting of specific molecular abnormalities characterizing adiposity offers an alternative approach to preventing cancer. Our goal in this review is to first discuss the major mechanisms contributing to the obesity-breast cancer link. We will also consider race, specifically black/white differences, as they relate to the association of obesity with breast cancer risk. Then we will enumerate strategies targeting these mechanisms to reduce BC risk, in large part by way of dietary interventions with potential to mitigate the cancer-promoting components of adiposity.

World Cancer Research Fund International: Continuous Update Project-systematic literature review and meta-analysis of observational cohort studies on physical activity, sedentary behavior, adiposity, and weight change and breast cancer risk

PURPOSE

The purpose of the present study was to systematically review the complex associations between energy balance-related factors and breast cancer risk, for which previous evidence has suggested different associations in the life course of women and by hormone receptor (HR) status of the tumor.

METHODS

Relevant publications on adulthood physical activity, sedentary behavior, body mass index (BMI), waist and hip circumferences, waist-to-hip ratio, and weight change and pre- and postmenopausal breast cancer risk were identified in PubMed up to 30 April 2017. Random-effects meta-analyses were conducted to summarize the relative risks across studies.

RESULTS

One hundred and twenty-six observational cohort studies comprising over 22,900 premenopausal and 103,000 postmenopausal breast cancer cases were meta-analyzed. Higher physical activity was inversely associated with both pre- and postmenopausal breast cancers, whereas increased sitting time was positively associated with postmenopausal breast cancer. Although higher early adult BMI (ages 18-30 years) was inversely associated with pre- and postmenopausal breast cancers, adult weight gain and greater body adiposity increased breast cancer risk in postmenopausal women, and the increased risk was evident for HR+ but not HR- breast cancers, and among never but not current users of postmenopausal hormones. The evidence was less consistent in premenopausal women. There were no associations with adult weight gain, inverse associations with adult BMI (study baseline) and hip circumference, and non-significant associations with waist circumference and waist-to-hip ratio that were reverted to positive associations on average in studies accounting for BMI. No significant associations were observed for HR-defined premenopausal breast cancers.

CONCLUSION

Better understanding on the impact of these factors on pre- and postmenopausal breast cancers and their subtypes along the life course is needed.

Animal foods and postmenopausal breast cancer risk: a prospective cohort study

The role of diet on breast cancer risk is not well elucidated but animal food sources may play a role through, for example, the pathway of the insulin-like growth factor 1 system or cholesterol metabolism. The aim of this study was to evaluate the association between animal foods and the risk of postmenopausal breast cancer. This study was embedded in the Rotterdam Study, a population-based prospective cohort study of subjects aged 55 years and over (61 % female). Dietary intake of different animal foods was assessed at baseline using a validated FFQ and adjusted for energy intake using the residual method. We performed Cox proportional hazards modelling to analyse the association between the intake of the different food sources and breast cancer risk after adjustment for socio-demographic, lifestyle and metabolic factors. During a median follow-up of 17 years, we identified 199 cases of breast cancer (6·2 %) among 3209 women. After adjustment for multiple confounders, no consistent association was found between the intake of red meat intake, poultry, fish or dairy products and breast cancer risk. However, we found that egg intake was significantly associated with a higher risk of breast cancer (hazard ratioQ4 v. Q1: 1·83; 95 % CI 1·20, 2·79; Ptrend=0·01). In conclusion, this study found that dietary egg intake but no other animal foods was associated with a higher risk of postmenopausal breast cancer. Further research on the potential mechanisms underlying this association is warranted.

Updating the role of obesity and cholesterol in breast cancer

BACKGROUND

Breast cancer is the second most common cause of cancer-related death among women. Advances in our understanding of the disease have translated into better diagnostics and more effective therapeutics, leading to earlier detection and improved outcomes. Several studies have pointed at lifestyle and environmental factors as contributory for the onset and progression of the disease. Obesity and cholesterol stand out for their potential causal relationship with breast cancer and ease of modification.

MAIN TEXT

Obesity and cholesterol represent risk factors for breast cancer, but their impact is largely affected by cofounding variables including menopausal status, disease subtype, and inflammation. Establishing a causal relationship between lifestyle factors and clinical outcomes may be challenging. Epidemiological studies and meta-analyses have rendered conflicting or sometimes contradictory results, possibly owing to the multifactorial nature of the disease. We discuss the supporting evidence and limitations in our understanding of obesity and cholesterol as risk factors for breast cancer.

CONCLUSIONS

There is sufficient evidence that obesity and cholesterol impact clinical outcomes. Physicians are advised to take steps to help patients with their weight, such as recommending dietary and lifestyle interventions.

Etiology of hormone receptor positive breast cancer differs by levels of histologic grade and proliferation

Limited epidemiological evidence suggests that the etiology of hormone receptor positive (HR+) breast cancer may differ by levels of histologic grade and proliferation. We pooled risk factor and pathology data on 5,905 HR+ breast cancer cases and 26,281 controls from 11 epidemiological studies. Proliferation was determined by centralized automated measures of KI67 in tissue microarrays. Odds ratios (OR), 95% confidence intervals (CI) and p-values for case-case and case-control comparisons for risk factors in relation to levels of grade and quartiles (Q1-Q4) of KI67 were estimated using polytomous logistic regression models. Case-case comparisons showed associations between nulliparity and high KI67 [OR (95% CI) for Q4 vs. Q1 = 1.54 (1.22, 1.95)]; obesity and high grade [grade 3 vs. 1 = 1.68 (1.31, 2.16)] and current use of combined hormone therapy (HT) and low grade [grade 3 vs. 1 = 0.27 (0.16, 0.44)] tumors. In case-control comparisons, nulliparity was associated with elevated risk of tumors with high but not low levels of proliferation [1.43 (1.14, 1.81) for KI67 Q4 vs. 0.83 (0.60, 1.14) for KI67 Q1]; obesity among women ≥50 years with high but not low grade tumors [1.55 (1.17, 2.06) for grade 3 vs. 0.88 (0.66, 1.16) for grade 1] and HT with low but not high grade tumors [3.07 (2.22, 4.23) for grade 1 vs. 0.85 (0.55, 1.30) for grade 3]. Menarcheal age and family history were similarly associated with HR+ tumors of different grade or KI67 levels. These findings provide insights into the etiologic heterogeneity of HR+ tumors.

Ceragenin CSA-13 as free molecules and attached to magnetic nanoparticle surfaces induce caspase-dependent apoptosis in human breast cancer cells via disruption of cell oxidative balance

Natural antimicrobial peptides and ceragenins, as non-peptide amphipathic mimics, have been proposed as anti-cancer agents. To date, it has been confirmed that cathelicidin LL-37 and ceragenin CSA-13, both in free form and immobilized on the surface of magnetic nanoparticles (MNP@LL-37, MNP@CSA-13) induce apoptosis in colon cancer cells. Nevertheless, the question remains whether ceragenins, as synthetic analogs of LL-37 peptide and mimicking a number of its properties, act as antineoplastic agents in breast cancer cells, where LL-37 peptide stimulates oncogenesis. Considering potential anticancer activity, we determined whether CSA-13 and MNP@CSA-13 might be effective against breast cancer cells. Our study provides evidence that both CSA-13 and MNP@CSA-13 decreased viability and inhibit proliferation of MCF-7 and MDA-MB-231 cells despite the protumorigenic properties of LL-37 peptide. Flow cytometry-based analyses revealed that ceragenin treatment results in increases in dead and PI-negative/low-viability cells, which was associated with glutathione (GSH) depletion and increased reactive oxygen species (ROS) generation followed by mitochondrial membrane depolarization, caspase activation, and DNA fragmentation. These findings demonstrate that both CSA-13 and MNP@CSA-13 cause disruption of the oxidative balance of cancer cells. This novel mechanism of ceragenin-mediated eradication of cancer cells suggest that these agents may be developed as a possible treatment of breast cancer.

Adipokines in hereditary breast cancer patients and healthy relatives

Background

The role of adipocytokines and ghrelin in hereditary breast cancer syndrome (HBCS) has never been tested.

Results

No significant differences in leptin, adiponectin and ghrelin plasma levels between cancer patients and healthy subjects was observed. Conversely, an higher level of adiponectin was shown in healthy subjects with BRCA 1/2 gene mutation vs those without (p < 0.03). Logistic regression analysis demonstrated that Adiponectin plasma level (OR 0.26; 95% CI:0.007–0.81; p < 0.02) and age (OR 5.51; 95% CI:1.78–19.71; p < 0.004) were the only factors independently associated with BMI; furthermore, Leptin plasma level (OR 0.23; 95% CI:0.06–0.76; p < 0.01) and age (OR 0.05; 95% CI:0.05–0.61; p < 0.007) resulted the only factors significantly associated with breast cancer.

Materials and Methods

We analyzed blood plasma expression of leptin, adiponectin and ghrelin using Bio-Plex platform in 25 breast cancer patients with HBCS and in 38 healthy relatives. BRCA 1/2 gene status (presence of pathogenic mutations by direct molecular sequencing), clinical-pathological characteristics and Body Mass Index (BMI) of each subject were recorded.

Conclusions

Adiponectin confirms to be associated with BMI also in subjects with HBCS. Leptin plasma level seems a direct and independent biomarker of a breast cancer risk. A validation of Leptin as a circulating biomarker of breast cancer development in larger series of HBCS subjects is needed.

Obesity and adverse breast cancer risk and outcome: Mechanistic insights and strategies for intervention

Answer questions and earn CME/CNE Recent decades have seen an unprecedented rise in obesity, and the health impact thereof is increasingly evident. In 2014, worldwide, more than 1.9 billion adults were overweight (body mass index [BMI], 25-29.9 kg/m2 ), and of these, over 600 million were obese (BMI ≥30 kg/m2 ). Although the association between obesity and the risk of diabetes and coronary artery disease is widely known, the impact of obesity on cancer incidence, morbidity, and mortality is not fully appreciated. Obesity is associated both with a higher risk of developing breast cancer, particularly in postmenopausal women, and with worse disease outcome for women of all ages. The first part of this review summarizes the relationships between obesity and breast cancer development and outcomes in premenopausal and postmenopausal women and in those with hormone receptor-positive and -negative disease. The second part of this review addresses hypothesized molecular mechanistic insights that may underlie the effects of obesity to increase local and circulating proinflammatory cytokines, promote tumor angiogenesis and stimulate the most malignant cancer stem cell population to drive cancer growth, invasion, and metastasis. Finally, a review of observational studies demonstrates that increased physical activity is associated with lower breast cancer risk and better outcomes. The effects of recent lifestyle interventions to decrease sex steroids, insulin/insulin-like growth factor-1 pathway activation, and inflammatory biomarkers associated with worse breast cancer outcomes in obesity also are discussed. Although many observational studies indicate that exercise with weight loss is associated with improved breast cancer outcome, further prospective studies are needed to determine whether weight reduction will lead to improved patient outcomes. It is hoped that several ongoing lifestyle intervention trials, which are reviewed herein, will support the systematic incorporation of weight loss intervention strategies into care for patients with breast cancer. CA Cancer J Clin 2017;67:378-397. © 2017 American Cancer Society.

Estrogen receptors in breast and bone: from virtue of remodeling to vileness of metastasis

Bone metastasis is a prominent cause of morbidity and mortality in cancer. High rates of bone colonization in breast cancer, especially in the subtype expressing estrogen receptors (ERs), suggest tissue-specific proclivities for metastatic tumor formation. The mechanisms behind this subtype-specific organ-tropism remains largely elusive. Interestingly, as the major driver of ER+ breast cancer, ERs also have important roles in bone development and homeostasis. Thus, any agents targeting ER will also inevitably affect the microenvironment, which involves the osteoblasts and osteoclasts. Yet, how such microenvironmental effects are integrated with direct therapeutic responses of cancer cells remain poorly understood. Recent findings on ER mutations, especially their enrichment in bone metastasis, raised even more provocative questions on the role of ER in cancer-bone interaction. In this review, we evaluate the importance of ERs in bone metastasis and discuss new avenues of investigation for bone metastasis treatment based on current knowledge.

Influence of occupation and education level on breast cancer stage at diagnosis, and treatment options in China: A nationwide, multicenter 10-year epidemiological study

The objective of this study was to evaluate the impact of occupation and education level of Chinese female breast cancer patients on their cancer staging at diagnosis, clinical and pathological features, rate of implementation, and selection of treatment.The medical charts of 4211 confirmed female breast cancer cases diagnosed between 1999 and 2008, from 7 breast cancer centers spread across the whole of China, were reviewed. Data including information on the patient's sociodemographic status, clinical and pathological characteristics, implementation of clinical examination and treatment modalities were analyzed. In parallel, the associations between different occupations and level of educational attainment were analyzed in relation to tumor stage through TNM staging, clinical and pathological characteristics, implementation of clinical examination, and treatment patterns. Multivariate logistic regression was used to identify whether the occupation and education level of patients are independent factors of TNM staging at diagnosis.There were significant differences among different occupation groups and the education level of patients in regards to pathological characteristics and treatment choice. Both the occupation and education level of patients were independent factors of TNM staging at diagnosis. For patients within the lower-income occupation or lower educational attainment group, the tumor stage was later, the rates of implementation of relevant investigations were lower, as were the rates of radiotherapy, chemotherapy, and endocrine therapy.This study suggests that strategies should work toward developing more accurate and effective breast cancer prevention and treatment strategies aimed specifically at patients with lower educational attainment levels and at specific occupation groups.

Central obesity and risks of pre- and postmenopausal breast cancer: a dose-response meta-analysis of prospective studies

Epidemiologic evidence has shown inconsistent findings regarding the relationships between abdominal fatness, as measured by waist circumferences (WC) or waist-to-hip ratio (WHR), and risks of pre- and postmenopausal breast cancer (BC). A dose-response meta-analysis of prospective studies was conducted to address these issues. Potentially eligible studies were identified by searching PubMed and EMBASE databases, and by carefully reviewing the bibliographies of retrieved publications and related reviews. The summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model. When the most fully adjusted RRs were combined, both WC (14 studies, RR _{per 10-cm increase}  = 1.06, 95% CI: 1.04-1.09, I²  = 29.9%) and WHR (15 studies, RR _{per 0.1-unit increase}  = 1.07, 95% CI: 1.01-1.14, I²  = 52.9%) were significantly positively associated with postmenopausal BC, but neither WC (eight studies, RR _{per 10-cm increase}  = 1.05, 95% CI: 0.99-1.10, I²  = 0%) nor WHR (11 studies, RR _{per 0.1-unit increase}  = 1.07, 95% CI: 0.95-1.21, I²  = 59.7%) were associated with premenopausal BC. The WHR-postmenopausal BC association lost statistical significance after correcting publication bias (RR _{per 0.1-unit increase}  = 1.06, 95% CI: 0.99-1.13). When considering BMI-adjusted RRs, WC was associated with both pre- (five studies, RR _{per 10-cm increase}  = 1.09, 95% CI: 1.02-1.16, I²  = 0%) and postmenopausal BC (seven studies, RR _{per 10-cm increase}  = 1.05, 95% CI: 1.02-1.08, I²  = 6.3%), whereas WHR was not associated with either pre- (seven studies, RR _{per 0.1-unit increase}  = 1.12, 95% CI: 0.94-1.34, I²  = 70.9%) or postmenopausal BC (eight studies, RR _{per 0.1-unit increase}  = 1.05, 95% CI: 0.98-1.13, I²  = 57.3%). Among non-current (former or never) users of hormone replacement therapy, the summary RR _{per 10-cm increase} of postmenopausal BC associated with WC was 1.08 (95% CI: 1.03-1.05, I²  = 69.2%, seven studies; BMI-adjusted RR = 1.05, 95% CI: 1.02-1.09, I²  = 22.8%, four studies). This meta-analysis indicates that central obesity measured by WC, but not by WHR, is associated with modestly increased risks of both pre- and postmenopausal BC independent of general obesity.

The Obesity-Breast Cancer Conundrum: An Analysis of the Issues

Breast cancer develops over a timeframe of 2-3 decades prior to clinical detection. Given this prolonged latency, it is somewhat unexpected from a biological perspective that obesity has no effect or reduces the risk for breast cancer in premenopausal women yet increases the risk for breast cancer in postmenopausal women. This conundrum is particularly striking in light of the generally negative effects of obesity on breast cancer outcomes, including larger tumor size at diagnosis and poorer prognosis in both pre- and postmenopausal women. This review and analysis identifies factors that may contribute to this apparent conundrum, issues that merit further investigation, and characteristics of preclinical models for breast cancer and obesity that should be considered if animal models are used to deconstruct the conundrum.

Body weight and risk of molecular breast cancer subtypes among postmenopausal Mediterranean women

Breast cancer (BC) is the most common malignant tumor in women, obesity is associated with increased BC incidence and mortality and high levels of circulating insulin may negatively impact on cancer incidence. In the present study, we investigated whether the strength of several anthropometric and metabolic parameters varies between BC molecular subtypes. Eligible cases were 991 non-metastatic BC patients recruited between January 2009 and December 2013. Anthropometric, clinical and immunohistochemical features were measured. Multivariate logistic regression models were built to assess HER2 positive BC risk, comparing (a) triple positive (TP) with luminal A, luminal B and triple negative (TN) and (b) HER2-enriched group with luminal A, luminal B and TN. We stratified patients in pre- and post-menopause: significant differences emerged for luminal A in relation to age: they were more likely to be older compared to other groups. Among postmenopausal patients, the adjusted multivariate analysis showed that high BMI and high waist circumference were inversely correlated to TP subtype when compared to luminal B (OR=0.48 and OR=0.49, respectively). Conversely, HOMA-IR was a risk factor for TP when compared to luminal A and TN (OR=2.47 and OR=3.15, respectively). Our findings suggest a potential role of higher abdominal fat in the development of specific BC molecular subtypes in postmenopausal women. Moreover, they support a potential role of insulin resistance in the development of HER2 positive BC, although this role appears to be stronger when hormone receptors are co-expressed, suggesting a difference in the etiology of these two BC subtypes.

Quantifying the Role of Circulating Unconjugated Estradiol in Mediating the Body Mass Index-Breast Cancer Association

BACKGROUND

Higher body mass index (BMI) and circulating estrogen levels each increase postmenopausal breast cancer risk, particularly estrogen receptor-positive (ER(+)) tumors. Higher BMI also increases estrogen production.

METHODS

We estimated the proportion of the BMI-ER(+) breast cancer association mediated through estrogen in a case-control study nested within the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Participants included 143 women with invasive ER(+) breast cancer and 268 matched controls, all postmenopausal and never having used hormone therapy at baseline. We used liquid chromatography-tandem mass spectrometry to measure 15 estrogens and estrogen metabolites in baseline serum. We calculated BMI from self-reported height and weight at baseline. We estimated the mediating effect of unconjugated estradiol on the BMI-ER(+) breast cancer association using Aalen additive hazards and Cox regression models.

RESULTS

All estrogens and estrogen metabolites were statistically significantly correlated with BMI, with unconjugated estradiol most strongly correlated [Pearson correlation (r) = 0.45]. Approximately 7% to 10% of the effect of overweight, 12% to 15% of the effect of obesity, and 19% to 20% of the effect of a 5 kg/m(2) BMI increase on ER(+) breast cancer risk was mediated through unconjugated estradiol. The BMI-breast cancer association, once adjusted for unconjugated estradiol, was not modified by further adjustment for two metabolic ratios statistically significantly associated with both breast cancer and BMI.

CONCLUSION

Circulating unconjugated estradiol levels partially mediate the BMI-breast cancer association, but other potentially important estrogen mediators (e.g., bioavailable estradiol) were not evaluated.

IMPACT

Further research is required to identify mechanisms underlying the BMI-breast cancer association.

The Relationship between Bone Mineral Density and Estrogen Receptor Positivity in Patients with Breast Cancer

OBJECTIVE

The effect of estrogen on bone mineral density (BMD) and breast cancer has been known for a long time. The aim of this study was to compare of the BMD of patients with breast cancer and healthy individuals, and to investigate the degree of correlation of estrogen receptor (ER) with BMD.

MATERIALS AND METHODS

Seventy-one patients with postmenopausal breast cancer and 79 healthy dividuals were included in the study. The patient demographics (age, menopause age, body mass index, number of children, BMD, Z scores, and estrogen status for breast cancer patients) were taken from hospital records.

RESULTS

No significant difference was detected between the case and control groups in lumbar region Z scores (p=0.074). At the femur neck, the control group Z scores was higher than patient group (p=0.002). BMI was higher in the patients with breast cancer (p=0.001). There was no statistically significant correlation between ER positivity, BMD, and BMI in ER-positive patients (p=0.495, p=0.8, p=0.846, respectively). There was no difference between the Z scores when the patients were divided into two groups as ER positive and negative (p=0.156, p=0.335, respectively).

CONCLUSION

This study revealed that there is no difference in lumbar region Z scores between patients with breast cancer and heathy controls; however, the Z scores were higher in the femur neck in the control group, and the BMI was lower in the patient group. Tumor ER positivity does not positively affect BMD.

Breast cancer risk factor associations differ for pure versus invasive carcinoma with an in situ component in case-control and case-case analyses

PURPOSE

Invasive ductal carcinoma (IDC) is diagnosed with or without a ductal carcinoma in situ (DCIS) component. Previous analyses have found significant differences in tumor characteristics between pure IDC lacking DCIS and mixed IDC with DCIS. We will test our hypothesis that pure IDC represents a form of breast cancer with etiology and risk factors distinct from mixed IDC/DCIS.

METHODS

We compared reproductive risk factors for breast cancer risk, as well as family and smoking history between 831 women with mixed IDC/DCIS (n = 650) or pure IDC (n = 181), and 1,620 controls, in the context of the Women's Circle of Health Study (WCHS), a case-control study of breast cancer in African-American and European-American women. Data on reproductive and lifestyle factors were collected during interviews, and tumor characteristics were abstracted from pathology reports. Case-control and case-case analyses were conducted using unconditional logistic regression.

RESULTS

Most risk factors were similarly associated with pure IDC and mixed IDC/DCIS. However, among postmenopausal women, risk of pure IDC was lower in women with body mass index (BMI) 25 to <30 [odds ratio (OR) 0.66; 95 % confidence interval (CI) 0.35-1.23] and BMI ≥ 30 (OR 0.33; 95 % CI 0.18-0.67) compared to women with BMI < 25, with no associations with mixed IDC/DCIS. In case-case analyses, women who breastfed up to 12 months (OR 0.55; 95 % CI 0.32-0.94) or longer (OR 0.47; 95 % CI 0.26-0.87) showed decreased odds of pure IDC than mixed IDC/DCIS compared to those who did not breastfeed.

CONCLUSIONS

Associations with some breast cancer risk factors differed between mixed IDC/DCIS and pure IDC, potentially suggesting differential developmental pathways. These findings, if confirmed in a larger study, will provide a better understanding of the developmental patterns of breast cancer and the influence of modifiable risk factors, which in turn could lead to better preventive measures for pure IDC, which have worse disease prognosis compared to mixed IDC/DCIS.

Cross-Sectional Associations between Body Size, Circulating Sex-Steroid Hormones and IGF Components among Healthy Chinese Women

The incidence of breast cancer has increased in Asian countries and rates of hormone receptor (HR) negative breast cancer exceed those of Western countries. Epidemiologic data suggest that the association between body size and BC risk may vary by HR status, and could differ geographically. While body size may influence BC risk by moderating the synthesis and metabolism of circulating sex-steroid hormones, insulin-like growth factor (IGF)-1 and related binding proteins, there is a dearth of literature among Asian women. We aimed to examine these specific associations in a sample of Chinese women. In Sichuan Province 143 women aged ≥40 years were recruited through outpatient services (2011–2012). Questionnaires, anthropometric measurements, and blood samples were utilized for data collection and linear regression was applied in data analyses. Among women <50 years we observed a non-monotonic positive association between body mass index (BMI) and 17β-estradiol, and a reversed J-shaped association between BMI and IGF-1 (p ≤0.05). We observed similar associations between waist-to-hip ratio and these markers. Our finding of augmented IGF-1 among women with low body mass may have implications for understanding breast tumor heterogeneity in diverse populations and should be evaluated in larger prospective studies with cancer outcomes.

Adiposity and cancer risk: new mechanistic insights from epidemiology

Excess body adiposity, commonly expressed as body mass index (BMI), is a risk factor for many common adult cancers. Over the past decade, epidemiological data have shown that adiposity-cancer risk associations are specific for gender, site, geographical population, histological subtype and molecular phenotype. The biological mechanisms underpinning these associations are incompletely understood but need to take account of the specificities observed in epidemiology to better inform future prevention strategies.

Impact of weight change during neoadjuvant chemotherapy on pathologic response in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an uncommon but aggressive subtype of breast cancer. Obesity has been associated with an increased risk of breast cancer and worse prognosis. Some studies suggest that obese patients are less likely to achieve pathologic complete response (pCR) to neoadjuvant chemotherapy (NCT) and experience worse overall survival. Ki-67 is a proliferation marker that correlates with tumor aggressiveness. The goal of this study was to examine the impact of weight change during NCT for TNBC on pathologic response and Ki-67 reduction. Retrospective review identified 173 TNBC patients treated between 2004 and 2011. Data were collected on patient demographics, pre- and post-NCT body mass index (BMI), Ki-67, and pCR. Data analysis was performed using the two-tailed Student's t-test, analysis of variance (ANOVA), and Fisher's exact test. Sixty-six patients met final study criteria. Forty-three patients lost weight during chemotherapy and 23 gained weight. Patients in the weight gain group were significantly younger (P = 0.0013). There was no significant difference between the two groups in terms of Ki-67 reduction (P = 0.98) or pCR (P = 0.58). When patients were separated into normal weight (BMI<25 kg/m(2) ), overweight (BMI ≥ 25 and <30 kg/m(2) ), and obese (BMI ≥ 30 kg/m(2) ), there was no significant difference in Ki-67 among those groups either before or after NCT. The degree of obesity did not have a significant impact on Ki-67 reduction. Weight change during NCT does not appear to correlate with Ki-67 change or achieving pCR in TNBC. This may reflect the nature of this subtype of breast cancer that is less responsive to the hormonal effects that adipose tissue exerts on cancer cell proliferation.

Body mass index and risk of breast cancer: a nonlinear dose-response meta-analysis of prospective studies

The role of Body Mass Index (BMI) for Breast Cancer (BC) remains to be great interest for a long time. However, the precise effect of nonlinear dose-response for BMI and BC risk is still unclear. We conducted a dose-response meta-analysis to quantitatively assess the effect of BMI on BC risk. Twelve prospective studies with 4,699 cases identified among 426,199 participants and 25 studies of 22,809 cases identified among 1,155,110 participants in premenopausal and postmenopausal groups, respectively, were included in this meta-analysis. Significant non-linear dose-response (P < 0.001) association was identified between BMI and BC risk in postmenopausal women. Individuals with BMI of 25, 30, and 35 kg/m² yielded relative risks (RRs) of 1.02 [95% confidence interval (CI): 0.98–1.06], 1.12 (95% CI: 1.01–1.24), and 1.26 (95% CI: 1.07–1.50), respectively, when compared to the mean level of the normal BMI range. However, inverse result though not significant was observed in premenopausal women. In conclusion, the results of this meta-analysis highlighted that obesity contributed to increased BC risk in a nonlinear dose-response manner in postmenopausal women, and it is important to realize that body weight control may be a crucial process to reduce BC susceptibility.

Effects of interval between age at first pregnancy and age at diagnosis on breast cancer survival according to menopausal status: a register-based study in Korea

Background

The influence of parity and time interval between age at first pregnancy (AFP) and age at diagnosis on breast cancer survival is not established in the same way as their influence on breast cancer risk. We aimed to investigate the association of time interval or parity with prognosis in pre- and postmenopausal women in Korea.

Methods

We conducted a retrospective study of 29,167 women with breast cancer through the Korean Breast Cancer Registry from 1993–2009. Information on reproductive factors, including breastfeeding, AFP, and parity were collected from a routine questionnaire. Conditional logistic regression was used to estimate the associations between menopausal status and overall mortality (OM) and breast-cancer-specific mortality (BCSM), adjusting for treatment and stage.

Results

High parity (≥5) increased the hazard ratios (HR) of BCSM (HR = 1.33, 95% confidence interval (CI): 0.83–2.11, p < 0.001) and OM (HR = 1.20, 95% CI: 0.85–1.68.73, p < 0.001) in premenopausal and postmenopausal women (BCSM, HR: 1.62, 95% CI: 0.93–2.82, p < 0.001; OM, HR = 1.58, 95% CI: 1.14–2.21, p <0.001). A longer time interval between age at breast cancer diagnosis and AFP reduced the HRs of BCSM (HR = 0.97, 95% CI: 0.96–0.98, p = 0.001) and OM (HR = 0.98, 95% CI: 0.97–0.98, p < 0.001) in premenopausal women, but had an adverse effect on the HR of OM (HR = 1.03, 95% CI: 1.02–1.03, p < 0.001) in postmenopausal women.

Conclusions

High parity (≥5) was associated with poor breast cancer prognosis in both pre- and postmenopausal women. The time intervals between reproductive events had different effects on breast cancer outcomes depending on menopausal status.

Electronic supplementary material

The online version of this article (doi:10.1186/1472-6874-14-113) contains supplementary material, which is available to authorized users.

The impact of overweight and obesity on breast cancer: data from Switzerland, so far a country little affected by the current global obesity epidemic

This review presents results from the project "The Impact of Overweight/Obesity on Breast Cancer: data from Switzerland". Swiss data is interesting because the general female population is distinctive in two areas when compared to that of most other industrialized countries: Switzerland has comparatively low rates of overweight (22-23%) and obesity (7-8%) and has rather stable rates of overweight and obesity. The entire project comprised three major issues: (I) etiology of breast cancer (BC). There is a consistently shown association between obesity and postmenopausal BC risk in countries with high obesity prevalence rates in the literature. In our Swiss study group, however, we did not find higher rates of overweight and obesity in postmenopausal BC cases than in the general population. A possible explanation for this observation may be a curvilinear dose-response relationship between BMI and postmenopausal BC risk, so that an increased risk may only be observed in populations with a high prevalence of obese/very obese women; (II) tumor characteristics. BMI was significantly associated with tumor size; this applied not only to the cases where the tumor was found by self-detection, but also to lesions detected by radiological breast examinations. In addition, a higher BMI was positively correlated with advanced TNM stage, unfavorable grading and a higher St. Gallen risk score. No associations were observed between BMI and histological subtype, estrogen receptor status, HER2 status and triple negative BC; (III) patient compliance and persistence towards adjuvant BC therapy. Many studies found that the prognosis of overweight/obese BC patients was significantly lower than that of normal weight patients. However, failure of compliance and persistence towards therapy on the part of the patient is not a contributing factor for this observed unfavorable prognosis. In most therapy modes, patients with increasing BMI demonstrated greater motivation and perseverance towards the recommended treatment.

Postmenopausal hormone replacement therapy and risk of acute pancreatitis: a prospective cohort study

BACKGROUND

Several case reports have suggested that women's use of exogenous sex hormones is associated with acute pancreatitis; however, relevant epidemiologic data are sparse. We examined the association between postmenopausal hormone replacement therapy and risk of acute pancreatitis.

METHODS

We conducted a prospective study involving 31,494 postmenopausal women (aged 48-83 yr) from the population-based Swedish Mammography Cohort. Participants completed a baseline questionnaire in 1997 assessing their use of hormone replacement therapy. We linked the cohort to the hospital-based Swedish National Patient Register to determine hospital admissions for acute pancreatitis through 2010. Relative risks (RRs) were calculated using Cox proportional hazard models.

RESULTS

Over a total follow-up of 389,456 person-years, we identified 237 cases of incident acute pancreatitis. The age-standardized incidence rates per 100,000 person-years were 71 cases among women who had ever used hormone replacement therapy and 52 cases among women who had never used such hormones. Among ever users of hormone replacement therapy, the multivariable-adjusted RR of acute pancreatitis was 1.57 (95% confidence interval [CI] 1.20-2.05) compared with never users. The risk did not differ by current or past use, but it seemed to be higher among women who used systemic therapy (RR 1.92, 95% CI 1.38-2.66) and among those with duration of therapy of more than 10 years (RR 1.87, 95% CI 1.11-3.17).

INTERPRETATION

Use of postmenopausal hormone replacement therapy was associated with increased risk of acute pancreatitis. Physicians should consider this potential increase in risk when prescribing such therapy.

Impact of body mass index on prognostically relevant breast cancer tumor characteristics

BACKGROUND

This study analyzes the association of body mass index (BMI) and prognostically relevant breast cancer (BC) characteristics in a country that has been rather spared of the global obesity epidemic.

PATIENTS AND METHODS

Based on 20-year data (1999-2009, n = 1,414) of the prospective relational BC database of the University Hospital Basel, Switzerland, the associations between BMI, tumor size and stage, histological subtype, grading, hormonal receptor status, HER2 status and 'triple-negative' status were evaluated. Multivariate analysis considered BMI and patient's age.

RESULTS

The association between increasing BMI and the above-mentioned variables were as follows (results described in each case: Beta-coefficient or odds ratio, 95% confidence interval, p value): tumor size, (1) entire cohort: 0.03 (0.01-0.05), p < 0.001, (2) tumor found by self-palpation: 0.05 (0.03-0.07), p < 0.001, (3) tumor found by radiological examination: 0.03 (0-0.07), p = 0.044; advanced TNM stage: 1.16 (1.02-1.31), p = 0.022; histological subtype: 1.04 (0.89-1.22), p = 0.602; unfavorable grading: 1.11 (1.00-1.25), p = 0.057; positive estrogen receptor status: 0.95 (0.83-1.09), p = 0.459; positive HER2 status: 0.92 (0.74-1.15), p = 0.467; presence of a 'triple-negative' carcinoma: 1.19 (0.93-1.52), p = 0.165. Consideration of only postmenopausal BC patients (n = 1,063) did attenuate the results, but did not change the direction of the associations with BMI.

CONCLUSION

BMI was positively associated with TNM stage, grading and tumor size for tumors that were found by self-detection, as well as for those lesions detected by radiological breast examinations.

Postmenopausal hormone replacement therapy and risk of cholecystectomy: a prospective cohort study

OBJECTIVE

Our aim of this study was to examine the association between the use of postmenopausal HRT and risk of cholecystectomy in Sweden, where the most common regimen of HRT (oral oestradiol in combination with testosterone-like progestin) has been different from those investigated in previous studies.

MATERIAL AND METHODS

We performed a prospective study of 27 892 postmenopausal women (aged 48-83 years) from the population-based Swedish Mammography Cohort. Use of HRT was assessed by a self-reported questionnaire at baseline in 1997, and the cohort was followed up through 2011 for procedures of cholecystectomy by linkage to the Swedish Patient Register. Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

During 362 728 person-years of follow-up (median 14 years), 995 cases of cholecystectomy were recorded. After adjustment for potential confounders, the HR of cholecystectomy was 1.52 (95% CI, 1.33-1.74) among ever users of HRT compared with never users. The risk did not differ by current or past use (p = 0.38) or duration of use (p = 0.65), but it did differ by indication of use (p = 0.006). Women who used HRT for systemic symptoms had a higher risk of cholecystectomy than those who used it for local symptoms (HR, 1.62; 95% CI, 1.41-1.87 vs HR, 1.21; 95% CI, 0.97-1.50).

CONCLUSIONS

This prospective study of postmenopausal women adds to the evidence that use of HRT may increase the risk of cholecystectomy.

Body mass index and breast cancer risk according to postmenopausal estrogen-progestin use and hormone receptor status

To assess the joint relationships among body mass index, menopausal status, and breast cancer according to breast cancer subtype and estrogen-progestin medication use, we conducted a meta-analysis of 89 epidemiologic reports published in English during 1980-2012 identified through a systematic search of bibliographic databases. Pooled analysis yielded a summary risk ratio of 0.78 (95% confidence interval (CI): 0.67, 0.92) for hormone receptor-positive premenopausal breast cancer associated with obesity (body mass index (weight (kg)/height (m)(2)) ≥30 compared with <25). Obesity was associated with a summary risk ratio of 1.39 (95% CI: 1.14, 1.70) for receptor-positive postmenopausal breast cancer. For receptor-negative breast cancer, the summary risk ratios of 1.06 (95% CI: 0.70, 1.60) and 0.98 (95% CI: 0.78, 1.22) associated with obesity were null for both premenopausal and postmenopausal women, respectively. Elevated postmenopausal breast cancer risk ratios associated with obesity were limited to women who never took estrogen-progestin therapy, with risk ratios of 1.42 (95% CI: 1.30, 1.55) among never users and 1.18 (95% CI: 0.98, 1.42) among users; too few studies were available to examine this relationship according to receptor subtype. Future research is needed to confirm whether obesity is unrelated to receptor-negative breast cancer in populations of postmenopausal women with low prevalence of hormone medication use.

The diverse distribution of risk factors between breast cancer subtypes of ER, PR and HER2: a 10-year retrospective multi-center study in China

Introduction

Hormone receptors, human epidermal growth factor receptor 2 and some risk factors determine therapies and prognosis of breast cancer. The risk factors distributed differently between patients with receptors. This study aimed to investigate the distribution of risk factors between subtypes of breast cancer by the 3 receptors in Chinese native women with a large sample size.

Methods

The multi-center study analyzed 4211 patient medical records from 1999 to 2008 in 7 regions of China. Data on patients’ demographic information, risk factors (menopausal status, parity, body mass index) and receptor statuses were extracted. Breast cancer subtypes included ER (+/−), PR (+/−), HER2 (+/−), 4 ER/PR and 4 molecular subtypes. Wilcoxon and Chi-square tests were used to estimate the difference. The unconditional logistic regression model was used for analysis, and presented p-value after Bonferroni correction in the results.

Results

Compared to patients with negative progesterone receptor, the positive patients were younger at diagnosis, and reported less likely in postmenopausal status and lower parity (p<0.05). Comparing with the subtype of ER+/PR+, ER+/PR− subtype were 4-year older at diagnosis (OR = 1.02), more likely to be postmenopausal (OR = 1.91) and more likely to have >1 parity (OR = 1.36) (p<0.05); ER−/PR− subtype were more likely to be postmenopausal (OR = 1.33) and have >1 parity (OR = 1.19) (p<0.05). In contrast to the luminal A subtype, triple negative subtype had a lower BMI (OR = 0.96) and ORs of overweight and obesity reduced by >20% (p<0.05).

Conclusion

In this study, it was found that Chinese female patients did have statistically significant differences of age, menopausal status, parity and body mass index between breast cancer subtypes. Studies are warranted to further investigate the risk factors between subtypes, which was meaningful for prevention and treatment among Chinese females.

Effect of body mass index on tumor characteristics and disease-free survival in patients from the HER2-positive adjuvant trastuzumab trial N9831

BACKGROUND

Data suggest that weight, and specifically body mass index (BMI), plays a role in breast cancer development and outcome. The authors hypothesized that there would be a correlation between BMI and clinical outcome in patients with early stage, human epidermal receptor 2 (HER2)-positive breast cancer enrolled in the N9831 adjuvant trial.

METHODS

Patients were grouped according to baseline BMI as follows: normal (BMI <25 kg/m(2)), overweight (BMI ≥25 kg/m(2) and <30 kg/m(2)), and obese (BMI ≥30 kg/m(2)). Disease-free survival (DFS) was estimated using the Kaplan-Meier method. Comparisons between treatment arms A, B, and C (chemotherapy with or without trastuzumab) were performed using a stratified Cox proportional hazards model.

RESULTS

Analysis was completed on 3017 eligible patients. Obese patients were more likely to be older and postmenopausal (P < .0001 for both), to have larger tumors (P = .002), and to have positive lymph nodes (P = .004). In the pooled analysis cohort, differences in DFS among the BMI groups were statistically significant (5-year DFS rate: 82.5%, 78.6%, and 78.5% for normal weight, overweight, and obese women, respectively; log-rank P = .02). The adjusted hazard ratio comparing the DFS of overweight women with the DFS of normal women was 1.30 (95% confidence interval, 1.06-1.61); and, comparing the DFS of obese women with the DFS normal women, the adjusted hazard ratio was 1.31 (95% confidence interval, 1.07-1.59). There were no statistically significant differences in DFS by weight group for women within any trial arm.

CONCLUSIONS

Patients with early stage, HER2-positive breast cancer and normal BMI had a better 5-year DFS compared with overweight and obese women. The current results indicated that adjuvant trastuzumab improves clinical outcome regardless of BMI.

Impact of recent parity on histopathological tumor features and breast cancer outcome in premenopausal Japanese women

Although previous studies have reported that onset at young age is associated with poor prognosis in breast cancer, the correlation between reproductive factors, breast cancer characteristics, and prognosis remains unclear. Five hundred and twenty-six premenopausal young women diagnosed with primary invasive breast cancer between January 2000 and December 2007 were included in this study. Patients were classified into four groups according to their reproductive history: women who gave birth within the previous 2 years (group A), women who gave birth between 3 and 5 years previously (group B), women who gave birth more than 5 years previously (group C), and nulliparous women (group N). The correlation between the time since last childbirth to diagnosis, histopathological tumor features, and breast cancer prognosis was evaluated. Breast cancer patients who had given birth more recently had more advanced stage tumors; larger sized tumors; a higher rate of axillary lymph node metastases; a higher histological tumor grade; and increased progesterone receptor (PgR)-, HER2+, and triple negative tumors than patients who had given birth less recently or not at all. Group A patients had significantly shorter survival times than patients in both groups C and N (log rank test; p < 0.001). After adjusting for tumor characteristics, the hazard ratio for death in group A was 2.19 compared with group N (p = 0.036), and the adjusted hazard ratio restricted to patients in group A with hormone-receptor-positive, and HER2- tumors was 3.07 (p = 0.011). Young breast cancer patients who had given birth more recently had tumors with more aggressive features and worse prognoses compared with patients who had given birth less recently or were nulliparous.

Associations between body mass index and molecular subtypes as well as other clinical characteristics of breast cancer in Chinese women

Background:

Several studies have shown a positive association between body mass index (BMI) and the development of hormone receptor-positive breast cancer in postmenopausal women; however, the associations between BMI groups and molecular subtypes have yet to be well defined in premenopausal breast cancer patients.

Methods:

A total of 2465 female breast cancer patients diagnosed at our institution were recruited for this study. Clinicopathologic information (including age, body height and weight, as well as tumor subtypes and stages) was collected; analyses of these characteristics and the associations between them were performed.

Results:

A total of 1951 cases were included in the study. The mean age was 47.3 years, the majority of patients were of normal weight, premenopausal, had stage 2 cancer, and did not present with positive nodes. The prevalence of the luminal A, luminal B, human epidermal growth factor receptor 2+, and triple-negative subtypes were 57.8%, 11.6%, 6.1%, and 24.5%, respectively. There were significant differences in the clinicopathologic features among BMI groups in premenopausal patients. The case-only odds ratio (OR) analysis revealed that normal weight patients tended to have luminal B cancer (OR = 1.4, P = 0.206), and overweight and obese patients tended to have triple-negative cancer in premenopausal patients (OR = 2.8, OR = 3.7, respectively; P < 0.001).

Conclusion:

In Chinese women, breast cancer came with these characteristics: young mean age (premenopause), luminal A subtype, and the majority of them were within a normal weight range. In premenopausal patients, underweight patients tended to have luminal A, lower human epidermal growth factor receptor 2+ expression, stage 1 and no positive node cancer. However, overweight and obese patients tended to have a triple-negative, stage 3, and lymph node metastatic cancer.

Anthropometric factors, physical activity, and breast cancer risk in relation to hormone receptor and menopausal status in Japanese women: a case-control study

PURPOSE

The associations between anthropometric factors, physical activity (PA), and breast cancer risk in terms of estrogen-receptor/progesterone-receptor (ER/PgR) status have been unclear in Japanese women. This case-control study was designed to evaluate these associations.

METHODS

From among female patients aged 30 years and over admitted to a single hospital in Japan between 1997 and 2009, 1,017 breast cancer cases (538ER+/PgR+, 125ER+/PgR-, 23 ER-/PgR+, 249 ER-/PgR-, and 82 missing) and 2,902 controls were selected. Height, weight, body mass index (BMI) (kg/m(2)), and time spent exercising (hours/week) were assessed using a self-administered questionnaire. Polytomous logistic regression analysis and tests for heterogeneity across ER+/PgR+ and ER-/PgR- were conducted.

RESULTS

Higher BMI was associated with a higher risk of ER+/PgR+ cancer among women overall [odds ratio (OR) = 2.41, 95 % confidence interval (CI) 1.37-4.23 for BMI ≥30.0; P(trend) = 0.0001] and postmenopausal women (OR = 6.24, 95 % CI 2.68-14.53 for BMI ≥30.0; P trend < 0.0001). A longer time spent exercising (more than 5 h/week) showed a decreased risk for any type of breast cancer among overall and pre- and postmenopausal women, although this did not reach statistical significance. Height was not associated with any risk.

CONCLUSIONS

Higher BMI is associated with an increased risk of ER+/PgR+ cancer among women overall and postmenopausal women. PA might be associated with a decreased risk of any type. To prevent breast cancer, weight control and PA are important.

Endocrine-related cancers and the role of AMPK

AMP-activated protein kinase (AMPK) is a master regulator of energy homeostasis involved in the regulation of a number of physiological processes including β-oxidation of fatty acids, lipogenesis, protein and cholesterol synthesis, as well as cell cycle inhibition and apoptosis. Important changes to these processes are known to occur in cancer due to changes in AMPK activity within cancer cells and in the periphery. This review aims to present findings relating to the role and regulation of AMPK in endocrine-related cancers. Obesity is a known risk factor for many types of cancers and a number of endocrine factors, including adipokines and steroid hormones, are regulated by and regulate AMPK. A clear role for AMPK in breast cancer is evident from the already impressive body of work published to date. However, information pertaining to its role in prostate cancer is still contentious, and future work should unravel the intricacies behind its role to inhibit, in some cases, and stimulate cancer growth in others. This review also presents data relating to the role of AMPK in cancers of the endometrium, ovary and colon, and discusses the possible use of AMPK-activating drugs including metformin for the treatment of all endocrine-related cancers.