Body mass index (BMI) and breast cancer: impact on tumor histopathologic features, cancer subtypes and recurrence rate in pre and postmenopausal women

The effect of BMI on survival outcome of breast cancer patients: a systematic review and meta-analysis

OBJECTIVE

The main goal of the present research is to explore the potential link of body mass index (BMI) with different survival metrics in breast cancer patients. Our aim is to offer the latest and most thorough meta-analysis, assessing the strength and reliability of the connection that BMI has with prognostic indicators in this disease.

PATIENTS AND METHODS

As of January 2024, we conducted a systematic literature search across PubMed, Embase, Web of Science, and the Cochrane Library databases. Our search aimed to identify studies examining BMI as an exposure factor, with breast cancer patients constituting the study population, and utilizing adjusted hazard ratio (HR) as the data type of interest.

RESULTS

The evidence synthesis incorporated a total of 61 eligible articles involving 201,006 patients. Being underweight posed a risk factor for overall survival (OS) in breast cancer patients compared to normal weight (HR 1.15, 95% CI 0.98-1.35; P = 0.08). Overweight or obesity, in comparison to normal weight, was a risk factor for OS (HR 1.18, 95% CI 1.14-1.23; P < 0.00001), disease-free survival (DFS) (HR 1.11, 95% CI 1.08-1.13; P < 0.00001), relapse-free survival (RFS) (HR 1.14, 95% CI 1.06-1.22; P = 0.03), and breast cancer-specific survival (BCSS) (HR 1.18, 95% CI 1.11-1.26; P < 0.00001), but not for progression-free survival (PFS) (HR 0.91, 95% CI 0.76-1.10; P = 0.33). Notably, in subgroup analyses, overweight patients achieved prolonged PFS (HR 0.80, 95% CI 0.64-0.99; P = 0.04), and compared to the obese population, the overweight cohort exhibited a significant difference in OS (HR 1.11, 95% CI 1.05-1.16; P < 0.00001) and DFS (HR 1.06, 95% CI 1.03-1.10; P = 0.0004), with a considerably stronger association. Furthermore, compared to HER- patients, HER + patients exhibited a greater predictive value for OS (HR 1.23, 95% CI 1.10-1.37; P = 0.0004), RFS (HR 1.30, 95% CI 1.03-1.64; P < 0.00001), and DFS (HR 1.10, 95% CI 1.03-1.17; P = 0.003).

CONCLUSIONS

The results of our meta-analysis reveal a notable association between BMI and various survival measures in breast cancer prognosis. These findings provide a solid basis for predicting breast cancer outcomes and implementing more effective therapeutic approaches.

Obesity Induces DNA Damage in Mammary Epithelial Cells Exacerbated by Acrylamide Treatment through CYP2E1-Mediated Oxidative Stress

Obesity and environmental toxins are risk factors for breast cancer; however, there is limited knowledge on how these risk factors interact to promote breast cancer. Acrylamide, a probable carcinogen and obesogen, is a by-product in foods prevalent in the obesity-inducing Western diet. Acrylamide is metabolized by cytochrome P450 2E1 (CYP2E1) to the genotoxic epoxide, glycidamide, and is associated with an increased risk for breast cancer. To investigate how acrylamide and obesity interact to increase breast cancer risk, female mice were fed a low-fat (LFD) or high-fat diet (HFD) and control water or water supplemented with acrylamide at levels similar to the average daily exposure in humans. While HFD significantly enhanced weight gain in mice, the addition of acrylamide did not significantly alter body weights compared to respective controls. Mammary epithelial cells from obese, acrylamide-treated mice had increased DNA strand breaks and oxidative DNA damage compared to all other groups. In vitro, glycidamide-treated COMMA-D cells showed significantly increased DNA strand breaks, while acrylamide-treated cells demonstrated significantly higher levels of intracellular reactive oxygen species. The knockdown of CYP2E1 rescued the acrylamide-induced oxidative stress. These studies suggest that long-term acrylamide exposure through foods common in the Western diet may enhance DNA damage and the CYP2E1-induced generation of oxidative stress in mammary epithelial cells, potentially enhancing obesity-induced breast cancer risk.

Temporal trends of breast cancer burden in the Western Pacific Region from 1990 to 2044: Implications from the Global Burden of Disease Study 2019

INTRODUCTION

Breast cancer (BC) is a malignant disease that occurs worldwide and poses serious health burden.

OBJECTIVES

To assess the prevalence of BC burden in the Western Pacific region (WPR) from 1990 to 2019, and to predict trends from 2020 to 2044. To analyze the driving factors and put forward the region-oriented improvement.

METHODS

Based on the Global Burden of Disease Study 2019, BC cases, deaths, disability-adjusted life years (DALYs) cases, age-standardized incidence rate (ASIR), age-standardized death rate (ASDR), and age-standardized DALYs rate in WPR from 1990 to 2019 was obtained and analysed. Age-period-cohort (APC) model was used to analyze age, period, and cohort effects in BC, and Bayesian APC (BAPC) was used to predict trends over the next 25 years.

RESULTS

In conclusion, BC incidence and deaths in the WPR have increased rapidly over the past 30 years and are expected to continue to increase between 2020 and 2044. Among behavioral and metabolic factors, high body-mass index was the main risk factor for BC mortality in middle-income countries, whereas alcohol use was the main risk factor in Japan. Age is a key factor in the development of BC, with 40 years being the critical point. Incidence trends coincide with the course of economic development.

CONCLUSIONS

The BC burden remains an essential public health issue in the WPR and will increase substantially in the future. More efforts should be made in middle-income countries to prompt the health behavior and minimize the burden of BC because these nations accounts for the majority of BC burden in the WPR.

The impact of BMI on breast cancer - an updated systematic review and meta-analysis

BACKGROUND

Breast cancer is the most frequent form of cancer in women all over the world. It is the main cause of cancer death and the most often diagnosed cancer in women in 140 of the world's 184 countries. The link between breast cancer risk and body mass index (BMI) has gotten increasing attention in recent years, although the results are still debatable. Therefore, the current systematic review and meta-analysis evaluate the impact of BMI on breast cancer.

METHODS

The current study was carried out as a systematic review and meta-analysis, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We systematically searched Cochrane, Google Scholar, PubMed, EMBASE and Scopus databases to identify eligible articles impact of BMI on breast cancer with the appropriate Medical Subject Headings (MeSH). The Newcastle-Ottawa checklist was used for the risk of assessment for the included studies. Meta-analysis was performed using Review Manager 5.3 software.

RESULTS

Forty-six studies were included in the current review, which met the selection criteria of the current review. Among included 46 studies in this review, 50% (n = 23) of the studies found the HER2 type of breast cancer followed by triple-negative and HR-positive. The obesity was significantly higher in the case group compared with the control group (P < .001). Heterogeneity between the 14 studies is medium (I2 = 72%). In this review, there was no significant relation between overweight and breast cancer in women (P > .05). Heterogenecity between the 14 studies is medium (I2 = 89%). However, after removing the publication bias a significant relation between overweightness and breast cancer in women (P = .0005) was observed.

CONCLUSION

Obese breast cancer patients are a specific type of patient. They are more likely to develop cancer. Their need to surgery and radiation may cause greater difficulties. Obesity and overweight in women greatly increase the risk of breast cancer, according to the findings of the current meta-analysis. To confirm these findings and understand the pathogenic pathways, more research is required.

SGLT2 Inhibitor Use and Risk of Breast Cancer Among Adult Women with Type 2 Diabetes

INTRODUCTION

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a relatively new class of antihyperglycemic agents, with the potential to inhibit breast cancer development. However, the association between SGLT2 inhibitors and risk of breast cancer in human studies is unclear.

OBJECTIVE

The aim of our study is to use a large national claims database to assess the association between SGLT2 inhibitor use and risk of breast cancer.

METHODS

We considered a study population of 158,483 adult women with type 2 diabetes who newly initiated SGLT2 inhibitors or dipeptidyl peptidase 4 (DPP4) inhibitors using Optum's deidentified Clinformatics Data Mart Database between 1 January 2013 and 31 March 2022. The association between SGLT2 inhibitor use and risk of breast cancer was examined using Cox proportional hazard models stratified by age in the overall sample and in a subsample based on propensity score and medication initiation time matching. The effect of medication use duration was explored.

RESULTS

With an average follow-up of 2.2 years, 2154 breast cancer cases were identified. There was no significant association between SGLT2 inhibitor use and the risk of breast cancer in overall sample (HR = 0.96; 95% CI 0.87, 1.06), in women younger than 51 years old (HR = 0.88; 95% CI 0.59, 1.32), or in women aged 51 years or older (HR = 0.95; 95% CI 0.86, 1.04). The results remained nonsignificant using matching, medication use duration, and sensitivity analyses.

CONCLUSION

Our findings suggest SGLT2 inhibitors use was not associated with breast cancer risk compared with DPP4 inhibitors use. Studies with longer follow-up and better adjustments are needed to confirm the finding.

Association of physical weight statuses defined by body mass index (BMI) with molecular subtypes of premenopausal breast cancer: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

The association between overweight/obesity and postmenopausal breast cancer has been proven. However, uncertainty exists regarding the association between physical weight statuses and premenopausal breast cancer subtypes. This study aimed to explore the association of body weight statuses with molecular subtypes of premenopausal breast cancer.

METHOD

A systematic search of Medline, PubMed, Embase, and Web of Science was performed. The Newcastle-Ottawa Scale (NOS) and the Joanna Briggs Institute (JBI) Critical Appraisal tools were used to evaluate the quality of the literature. STATA and R software were used to analyze the extracted data.

RESULT

The meta-analysis included 35 observational studies with a total of 41,049 premenopausal breast cancer patients. The study showed that the proportion of underweight patients was 4.8% (95% CI = 3.9-5.8%, P = 0.01), overweight was 29% (95%CI = 27.1-30.9%, P < 0.01), obesity was 17.8% (95% CI = 14.9-21.2%, P < 0.0001), and normal weight was 51.6% (95% CI = 46.7-56.5%, P < 0.0001). The pooled results showed that in comparison to the normal weight group, being physically underweight is related to a 1.44-fold risk (OR = 1.44, 95%CI = 1.28-1.63, P < 0.0001) of HER2 + breast cancer. Overweight is related to a 1.16-fold risk (OR = 1.16, 95%CI = 1.06-1.26, P = 0.002) of TNBC and a 16% lower risk (OR = 0.84, 95%CI = 0.75-0.93, P = 0.001) of ER + breast cancer. When compared to underweight/normal weight populations, both overweight (OR = 0.74, 95%CI = 0.56-0.97, P = 0.032) and obesity (OR = 0.70, 95%CI = 0.50-0.98, P = 0.037) can reduce the risk of ER + PR + breast cancer.

CONCLUSION

In the premenopausal breast cancer population, the distribution of patients' numbers with different weight statuses was significantly distinct among the various breast cancer subtypes. Additionally, the associations between physical weight statuses and the risk of premenopausal breast cancer subtypes are divergent.

The prognostic impact of body mass index on female breast cancer patients in underdeveloped regions of northern China differs by menopause status and tumor molecular subtype

There is growing evidence that higher body mass index (BMI) is associated with lower survival in breast cancer patients. The aim of this study was to investigate whether there is an association between body mass index (BMI) at breast cancer diagnosis and breast cancer prognosis and whether this association is dependent on menopausal status and tumor subtype in a less developed population in northern China. We collected 1,225 patients with primary invasive cancer in stage I-IIIC for retrospective analysis from October 2010 to December 2020. We used Kaplan-Meier and Cox regression analyses and estimated the relationship between baseline BMI and breast cancer-specific survival (BCSS). Next, we further evaluated whether the effect of BMI on breast cancer prognosis differed by menopausal status and tumor subtype. We found that death rate and prognosis were worse for patients with BMI ≥ 24, more than four positive lymph nodes, and triple negative status. Interestingly, BMI played a different prognostic role depending on tumor subtype and menopausal status. For premenopausal women, patients with BMI ≥ 24 had significantly lower BCSS compared to those with BMI < 24 in human epidermal growth factor receptor 2 (HER2) overexpression (HR: 4.305, p = 0.004) and triple negative subtypes (HR: 1.775, p = 0.048). By contrast, there was no association between BMI ≥ 24 and higher death regardless of tumor subtype in post-menopausal patients (p > 0.05). BMI influences breast cancer outcome depending on tumor subtype and menopause. BMI ≥ 24 might be a risk factor for BCSS, particularly in premenopausal women with HER2 overexpression or triple negative subtype. In contrast, BMI ≥ 24 was not associated with higher death regardless of tumor subtype in post-menopausal patients.

Association of body mass index with clinicopathological features and survival in patients with primary invasive lobular breast cancer

PURPOSE

Invasive lobular carcinoma (ILC) represents up to 15% of all breast carcinomas. While the proportion of women with overweight and obesity increases globally, the impact of body mass index (BMI) at primary diagnosis on clinicopathological features of ILC and the prognosis of the patients has not been investigated yet.

PATIENTS AND METHODS

We performed a multicentric retrospective study including patients diagnosed with non-metastatic pure ILC. The association of BMI at diagnosis with clinicopathological variables was assessed using linear or multinomial logistic regression. Univariable and multivariable survival analyses were performed to evaluate the association of BMI with disease-free survival (DFS), distant recurrence-free survival (DRFS), and overall survival (OS).

RESULTS

The data of 2856 patients with ILC and available BMI at diagnosis were collected, of which 2570/2856 (90.0%) had oestrogen receptor (ER)-positive and human epidermal growth factor receptor (HER2) not amplified/overexpressed (ER+/HER2-) ILC. Of these 2570 patients, 80 were underweight (3.1%), 1410 were lean (54.9%), 712 were overweight (27.7%), and 368 were obese (14.3%). Older age at diagnosis, a higher tumour grade, a larger tumour size, a nodal involvement, and multifocality were associated with a higher BMI. In univariable models, higher BMI was associated with worse outcomes for all end-points (DFS: hazard ratio (HR) 1.21, 95CI 1.12-1.31, p value<0.01; DRFS: HR 1.25, 95CI 1.12-1.40, p value<0.01; OS: HR 1.25, 95CI 1.13-1.37, p value<0.01). This association was not statistically significant in multivariable analyses (DFS: HR 1.09, 95CI 0.99-1.20, p value 0.08; DRFS: HR 1.03, 95CI 0.89-1.20, p value 0.67; OS: HR 1.11, 95CI 0.99-1.24, p value 0.08), whereas grade, tumour size, and nodal involvement were still prognostic for all end-points.

CONCLUSION

Worse prognostic factors such as higher grade, larger tumour size, and nodal involvement are associated with higher BMI in ER+/HER2- ILC, while there was no statistical evidence for an independent prognostic role for BMI. Therefore, we hypothesise that the effect of BMI on survival could be mediated through its association with these clinicopathological variables.

Geospatial Associations between Female Breast Cancer Mortality Rates and Environmental Socioeconomic Indicators for North Carolina

In North Carolina, over 6000 women will be diagnosed with breast cancer yearly, and over 1000 will die. It is well known that environmental conditions contribute greatly to health outcomes, and many of these factors include a geographic component. Using death data records from 2003-2019 extracted from North Carolina Vital Statistics Dataverse, a spatial database was developed to map and analyze female breast cancer mortality rates at the ZIP code scale in North Carolina. Thirty-nine hot spots and thirty cold spots of age-adjusted death rates were identified using the Getis-Ord analysis. Two-tailed t-tests were run between each cohort for environmental socioeconomic-related factors associated with breast cancer progression and mortality. The median age and household income of individuals who resided in ZIP codes with the highest breast cancer mortality were significantly lower than those who lived in ZIP codes with lower breast cancer mortality. The poverty rate, percentage of SNAP benefits, and the percentage of minorities were all significantly higher (p < 0.05, p < 0.001, and p < 0.001) in ZIP codes with high breast cancer rates. High-quality (ZIP code) granular cancer data were developed for which detailed analysis can be performed for future studies.

Application of SHAP for Explainable Machine Learning on Age-Based Subgrouping Mammography Questionnaire Data for Positive Mammography Prediction and Risk Factor Identification

Mammography is considered the gold standard for breast cancer screening. Multiple risk factors that affect breast cancer development have been identified; however, there is an ongoing debate regarding the significance of these factors. Machine learning (ML) models and Shapley Additive Explanation (SHAP) methodology can rank risk factors and provide explanatory model results. This study used ML algorithms with SHAP to analyze the risk factors between two different age groups and evaluate the impact of each factor in predicting positive mammography. The ML model was built using data from the risk factor questionnaires of women participating in a breast cancer screening program from 2017 to 2021. Three ML models, least absolute shrinkage and selection operator (lasso) logistic regression, extreme gradient boosting (XGBoost), and random forest (RF), were applied. RF generated the best performance. The SHAP values were then applied to the RF model for further analysis. The model identified age at menarche, education level, parity, breast self-examination, and BMI as the top five significant risk factors affecting mammography outcomes. The differences between age groups ranked by reproductive lifespan and BMI were higher in the younger and older age groups, respectively. The use of SHAP frameworks allows us to understand the relationships between risk factors and generate individualized risk factor rankings. This study provides avenues for further research and individualized medicine.

Excess body weight significantly affects systemic and tumor inflammatory status and correlates to poor prognosis parameters in patients with breast cancer

Introduction

Obesity is a pro-inflammatory disease critical for developing breast cancer (BC), which impacts the profiles of systemic inflammatory mediators and determinants of different disease clinical outcomes remains little explored.

Methods

A total of 195 patients diagnosed with breast cancer were included. Aiming to exclude chemotherapy interference on circulating mediators, samples were collected at diagnosis, out of the treatment period. Patients were classified as normal weight (BMI up to 24.9 kg/m2) or overweight (BMI ≥25.0 kg/m2). Serum levels of IL-4, IL-12, hydroperoxides, and nitric oxide metabolites (NOx) were measured. Also, tumor expression of inducible nitric oxide synthase (iNOS), TGF-β1, CD4⁺, and CD8⁺ lymphocytes were evaluated.

Results

IL-4 levels were significantly increased in the overweight BC group (p = 0.0329), including patients with luminal B subtype (p = 0.0443), presence of lymph node metastases (p = 0.0115) and age of diagnosis below 50 years, (p = 0.0488). IL-12 levels were significantly increased in overweight BC patients with lymph node metastases (p = 0.0115). Hydroperoxides were increased in overweight BC patients (p = 0.0437), including those with tumors smaller than 2 cm (p = 0.05). NOx levels were also increased in overweight BC patients, including those with luminal B disorders (p = 0.0443), high-grade tumors (p = 0.0351) and lymph node metastases (p = 0.0155). The expression of iNOS (p < 0.001) and TCD4+ lymphocytes (p = 0.0378) was significantly investigated in tumor biopsies from overweight BC women.

Conclusions

These data provide a picture of the influence of excess body weight on inflammatory mediators' systemic and tumoral profiles, especially in patients displaying poor outcome BC.

Postdiagnosis body fatness, weight change and breast cancer prognosis: Global Cancer Update Program (CUP global) systematic literature review and meta-analysis

Previous evidence on postdiagnosis body fatness and mortality after breast cancer was graded as limited-suggestive. To evaluate the evidence on body mass index (BMI), waist circumference, waist-hip-ratio and weight change in relation to breast cancer prognosis, an updated systematic review was conducted. PubMed and Embase were searched for relevant studies published up to 31 October, 2021. Random-effects meta-analyses were conducted to estimate summary relative risks (RRs). The evidence was judged by an independent Expert Panel using pre-defined grading criteria. One randomized controlled trial and 225 observational studies were reviewed (220 publications). There was strong evidence (likelihood of causality: probable) that higher postdiagnosis BMI was associated with increased all-cause mortality (64 studies, 32 507 deaths), breast cancer-specific mortality (39 studies, 14 106 deaths) and second primary breast cancer (11 studies, 5248 events). The respective summary RRs and 95% confidence intervals per 5 kg/m2 BMI were 1.07 (1.05-1.10), 1.10 (1.06-1.14) and 1.14 (1.04-1.26), with high between-study heterogeneity (I2  = 56%, 60%, 66%), but generally consistent positive associations. Positive associations were also observed for waist circumference, waist-hip-ratio and all-cause and breast cancer-specific mortality. There was limited-suggestive evidence that postdiagnosis BMI was associated with higher risk of recurrence, nonbreast cancer deaths and cardiovascular deaths. The evidence for postdiagnosis (unexplained) weight or BMI change and all outcomes was graded as limited-no conclusion. The RCT showed potential beneficial effect of intentional weight loss on disease-free-survival, but more intervention trials and well-designed observational studies in diverse populations are needed to elucidate the impact of body composition and their changes on breast cancer outcomes.

Impact of obesity, lifestyle factors and health interventions on breast cancer survivors

The incidences of both breast cancer and obesity are rising in the UK. Obesity increases the risk of developing breast cancer in the postmenopausal population and leads to worse outcomes in those of all ages treated for early-stage breast cancer. In this review we explore the multifactorial reasons behind this association and the clinical trial evidence for the benefits of physical activity and dietary interventions in the early and metastatic patient groups. As more people with breast cancer are cured, and those with metastatic disease are living longer, cancer survivorship is becoming increasingly important. Therefore, ensuring the long-term implications of cancer and cancer treatment are addressed is vital. Although there remains a lack of definitive evidence that deliberate weight loss after a diagnosis of breast cancer reduces disease recurrence, a number of studies have reported benefits of weight loss and of physical activity. However, the limited data currently available mean that clinicians remain unclear on the optimal lifestyle advice to give their patients. Further high-quality research is needed to provide this evidence base, which will be required to optimise clinical care and for the commissioning of lifestyle interventions in the UK in breast cancer survivors.

Association of hypertension, hyperlipidemia, obesity, and demographic risk factors with breast cancer in Bangladeshi women

In recent years, breast cancer incidences and related deaths have been rising among Bangladeshi women and will be a major threat by 2040. So, conducting more population-based studies is crucial. This case-control study was designed to quantitatively evaluate potential risk factors for breast cancer. In this population-based case-control study, 52 random breast cancer cases and 59 matched healthy controls, aged between 25 and 70 years, were included. The breast cancer patient samples were collected from the National Institute of Cancer Research and Hospital (NICRH), Dhaka, Bangladesh, from December 2021 to February 2022. The study was conducted fully following the Declaration of Helsinki guidelines. The collected socio-demographic data and blood samples of the study participants were analyzed. Chi-square analysis was used to compare study characteristics between cases and controls, Odds ratios (ORs) with 95% confidence intervals (CIs) were derived by univariate-logistic regression, and models were adjusted where necessary for study characteristics. Summary demographic characteristics of the 111 study participants suggested that higher age: (≥45): [OR 4.38, 95% CI (1.94-9.89), P value <.001], height: (<1.5 m): [OR 3.01, 95% CI (1.12-8.12), P value .029], low-incomes: [OR 6.83, 95% CI (2.11-22.05), P value .001], and illiteracy: [OR 12.65, 95% CI (3.49-45.79), P value .0001] showed significant correlations with breast cancer. The patient's body mass index (BMI) (≥30) indicated an association with breast cancer: [OR 3.91, 95% CI (1.00-15.31), P value .05]. The lipid profile: [triglycerides (TG): OR = 3.20, 95% CI (1.36-7.53), P value .008; TG/high-density lipid (HDL): OR = 8.82, 95% CI (2.81-27.68), P value <.001; and a lowered HDL: OR = 3.32, 95% CI (1.38-7.98), P value .007], hypertension: [systolic: OR 4.32, 95% CI (1.71-10.93), P value .002; and diastolic: OR 7.32, 95% CI (2.51-21.34), P value <.001], and gastric issues: [OR 6.07, 95% CI (2.00-18.37), P value .001], all showed significant association with breast cancer. The ER- breast cancer subtype was significantly associated with the overweight (OW) group (P value .046) whereas the PR-patients were significantly higher in the normal BMI group (P value .013). Results from this study might aid in the prevention, management, and raising of awareness against the specific risk factors among Bangladeshi women in near future.

The influence of age, menstrual state and body mass index on the relation between osteopenia and osteoporosis associated with breast cancer

Osteoporosis and body mass index (BMI) have been reported to be associated with breast cancer. The correlation between other types of bone loss and breast cancer requires further illustrative evidence. Effect of age and menstrual state on the relationship of osteoporosis, osteopenia and BMI with breast cancer was evaluated in this study. Two hundred breast cancer patients and 200 breast cancer-free patients were included in a case-control study. Bone mineral density (BMD) and BMI were determined in all subjects. Postmenopause was the most frequent menstrual state. osteopenia was found to be significant in breast cancer patients and osteoporosis was significant in another group of women. There was no significant difference between breast cancer patients and control women in terms of age and menstrual status. Obesity was common in all subjects. In conclusion, bone loss rates are significantly low in breast cancer patients relative to healthy women. There was no significant impact of age, menstrual status or BMI on the development of osteopenia or osteoporosis in breast cancer patients. In addition, BMD analytical results may identify the appropriate treatment for bone loss. A routine check-up of osteopenia or osteoporosis is highly recommended for breast cancer patients.Impact StatementWhat is already known on this subject? Breast cancer may be associated with a wide variety of human body parameters. These parameters can include age, body mass index (BMI), obesity and menstrual status. There is also a correlation between osteoporosis and breast cancer.What do the results of this study add? Osteopenia is the most frequent form of bone loss among women with breast cancer. In contrast, osteoporosis as the worst stage of bone loss is unusual in these patients. Factors such as age, menstruation and BMI have no effect on the development of breast cancer.What are the implications of these findings for clinical practice and/or further research? Identification of the type of bone loss in women with breast cancer is essential to determine the appropriate type of therapy.

Breast cancer microenvironment and obesity: challenges for therapy

Women with obesity who develop breast cancer have a worsened prognosis with diminished survival rates and increased rates of metastasis. Obesity is also associated with decreased breast cancer response to endocrine and chemotherapeutic treatments. Studies utilizing multiple in vivo models of obesity as well as human breast tumors have enhanced our understanding of how obesity alters the breast tumor microenvironment. Changes in the complement and function of adipocytes, adipose-derived stromal cells, immune cells, and endothelial cells and remodeling of the extracellular matrix all contribute to the rapid growth of breast tumors in the context of obesity. Interactions of these cells enhance secretion of cytokines and adipokines as well as local levels of estrogen within the breast tumor microenvironment that promote resistance to multiple therapies. In this review, we will discuss our current understanding of the impact of obesity on the breast tumor microenvironment, how obesity-induced changes in cellular interactions promote resistance to breast cancer treatments, and areas for development of treatment interventions for breast cancer patients with obesity.

The role of obesity and bariatric surgery-induced weight loss in breast cancer

Obesity is a complex metabolic condition considered a worldwide public health crisis, and a deeper mechanistic understanding of obesity-associated diseases is urgently needed. Obesity comorbidities include many associated cancers and are estimated to account for 20% of female cancer deaths in the USA. Breast cancer, in particular, is associated with obesity and is the focus of this review. The exact causal links between obesity and breast cancer remain unclear. Still, interactions have emerged between body mass index, tumor molecular subtype, genetic background, and environmental factors that strongly suggest obesity influences the risk and progression of certain breast cancers. Supportive preclinical research uses various diet-induced obesity models to demonstrate that weight loss, via dietary interventions or changes in energy expenditure, reduces the onset or progression of breast cancers. Ongoing and future studies are now aimed at elucidating the underpinning mechanisms behind weight-loss-driven observations to improve therapy and outcomes in patients with breast cancer and reduce risk. This review aims to summarize the rapidly emerging literature on obesity and weight loss strategies with a focused discussion of bariatric surgery in both clinical and preclinical studies detailing the complex interactions between metabolism, immune response, and immunotherapy in the setting of obesity and breast cancer.

Response to immune checkpoint blockade improved in pre-clinical model of breast cancer after bariatric surgery

Bariatric surgery is a sustainable weight loss approach, including vertical sleeve gastrectomy (VSG). Obesity exacerbates tumor growth, while diet-induced weight loss impairs progression. It remains unknown how bariatric surgery-induced weight loss impacts cancer progression or alters response to therapy. Using a pre-clinical model of obesity followed by VSG or diet-induced weight loss, breast cancer progression and immune checkpoint blockade therapy were investigated. Weight loss by VSG or weight-matched dietary intervention before tumor engraftment protected against obesity-exacerbated tumor progression. However, VSG was not as effective as diet in reducing tumor burden despite achieving similar weight and adiposity loss. Leptin did not associate with changes in tumor burden; however, circulating IL-6 was elevated in VSG mice. Uniquely, VSG tumors displayed elevated inflammation and immune checkpoint ligand PD-L1+ myeloid and non-immune cells. VSG tumors also had reduced T lymphocytes and markers of cytolysis, suggesting an ineffective anti-tumor microenvironment which prompted investigation of immune checkpoint blockade. While obese mice were resistant to immune checkpoint blockade, anti-PD-L1 potently impaired tumor progression after VSG through improved anti-tumor immunity. Thus, in formerly obese mice, surgical weight loss followed by immunotherapy reduced breast cancer burden. Finally, we compared transcriptomic changes in adipose tissue after bariatric surgery from patients and mouse models. A conserved bariatric surgery-associated weight loss signature (BSAS) was identified which significantly associated with decreased tumor volume. Findings demonstrate conserved impacts of obesity and bariatric surgery-induced weight loss pathways associated with breast cancer progression.

As the number of people classified as obese rises globally, so do obesity-related health risks. Studies show that people diagnosed with obesity have inflammation that contributes to tumor growth and their immune system is worse at detecting cancer cells. But weight loss is not currently used as a strategy for preventing or treating cancer.

Surgical procedures for weight loss, also known as ‘bariatric surgeries’, are becoming increasingly popular. Recent studies have shown that individuals who lose weight after these treatments have a reduced risk of developing tumors. But how bariatric surgery directly impacts cancer progression has not been well studied: does it slow tumor growth or boost the anti-tumor immune response?

To answer these questions, Sipe et al. compared breast tumor growth in groups of laboratory mice that were obese due to being fed a high fat diet. The first group of mice lost weight after undergoing a bariatric surgery in which part of their stomach was removed. The second lost the same amount of weight but after receiving a restricted diet, and the third underwent a fake surgery and did not lose any weight. The experiments found that surgical weight loss cuts breast cancer tumor growth in half compared with obese mice. But mice who lost the same amount of weight through dietary restrictions had even less tumor growth than surgically treated mice.

The surgically treated mice who lost weight had more inflammation than mice in the two other groups, and had increased amounts of proteins and cells that block the immune response to tumors. Giving the surgically treated mice a drug that enhances the immune system’s ability to detect and destroy cancer cells reduced inflammation and helped shrink the mice’s tumors. Finally, Sipe et al. identified 54 genes which were turned on or off after bariatric surgery in both mice and humans, 11 of which were linked with tumor size.

These findings provide crucial new information about how bariatric surgery can impact cancer progression. Future studies could potentially use the conserved genes identified by Sipe et al. to develop new ways to stimulate the anti-cancer benefits of weight loss without surgery.

Relationship between body mass index and cholesterol levels with histopathological grading of breast cancer

BACKGROUND

Breast cancer, a global health problem with a high mortality rate, has several risk factors, including obesity and increased lipid profile. Postmenopausal obesity is associated with estrogen production from adipose tissue, while abnormal cell growth is triggered by insulin-like growth factor 1 (IGF-1) and insulin. Obesity could be assessed by measuring body mass index (BMI). An increase in lipid profile signifies an increased risk for breast cancer. Histopathological findings in the form of grading and differentiation can indicate how serious the condition is. Breast cancer with good differentiation is always associated with a positive prognosis.

OBJECTIVE

This observational analytic study aims to determine the relationship between BMI and cholesterol levels based on the menopausal status and the histopathological grading findings of breast cancer patients.

METHODS

The observational cross-sectional study analyzed histopathological grading, total cholesterol level, and body mass index. Data were analyzed with Spearman rank correlation statistical test, and the results are significant when the p-value is <0.05.

RESULTS

Analyzing the relationship between cholesterol levels and histopathological gradings indicated a moderate correlation. The results of another correlation test based on menopausal status showed a weak correlation value, while menopause was said to be significant, indicating a moderate correlation. However, results from the analysis of BMI data in the menopausal subject group were associated with histopathological assessment.

CONCLUSIONS

There is a relationship between cholesterol levels and histopathological degrees in the two menopausal status groups. However, no relationship was found between BMI and the histopathological grades of breast cancer.

Pre-treatment high body mass index is associated with poor survival in Asian premenopausal women with localized breast cancer

Background: Obesity is associated with poor prognosis in breast cancer patients. This study aimed to evaluate the effect of obesity measured by body mass index (BMI) on survival of Taiwanese breast cancer patients in a single institution.

Methods: We observed 5000 patients who were diagnosed with stage I-III breast cancer between 1990 and 2005. Information on BMI at diagnosis, and clinical follow-up for disease recurrence and death, up to 20 years post-diagnosis were available. BMI (in kg/m²) categories included normal weight (BMI<24), overweight (24≤BMI<27), and obesity (BMI≥27), according to recommendations from the Bureau of Health Promotion of Taiwan. The role of BMI and other known prognostic factors for patient survival were evaluated in this patient cohort.

Results: Obesity was associated with advanced stage, higher nuclear grade, and higher percentages of estrogen receptor (ER) positive. The median age of patients with a higher BMI was greater than the median age of patients with a lower BMI. Obesity was an independent prognostic factor of overall survival (OS) (P<0.001), but not disease-free survival (DFS) (P=0.067). We subsequently analyzed the impact of age-stratified BMI (age<50 and age≥50 years) to ameliorate the impact of age bias. Following subset analyses, obesity correlated with shorter DFS (P=0.004) and OS (P=0.009) only in women<50 years of age. Multivariate analysis revealed that BMI was an independent prognostic factor for both DFS and OS in this group of patients. Subset analysis revealed that in women <50 years old, the impact of BMI on survival was associated with higher stage, ER negativity.

Conclusion: BMI is an independent prognostic factor of OS and DFS in breast cancer patients aged<50 years. Although the cause-effect relationship between obesity and survival is unclear, we recommend that weight control measures in young breast cancer survivors should be considered.

The Effect of Body Mass Index on Initial Breast Cancer Stage Among Korean Women

BACKGROUND

The relationship between obesity and breast cancer stage is not well-known in the Korean population. This study aimed to identify the effect of body mass index (BMI) on initial breast cancer stage.

PATIENTS AND METHODS

Among patients who underwent surgery for breast cancer (stages 0-III) from June 2003 to December 2018, we analyzed 4510 patients for whom there were BMI data.

RESULTS

The average BMI of our patients was 23.5 (14.2-44.9). In total, 4.6% and 24.2% of the patients had a BMI of ≥30 and 25-29.9, respectively. In the patients with obesity, the proportion of T2 to T4 was 41.4%, which was higher than that in patients with a BMI of 25 to 29 (28.4%; P = .001) or a BMI of <25 (23.3%; P < .001). There was no difference in positive rates of estrogen receptor and progesterone receptor with BMI, but obese patients were less likely to be human epidermal growth factor receptor 2 positive. Patients with higher stages were more likely to have a higher BMI. The effect of BMI on stage was stronger in patients <50 years (odds ratio, 2.439; 95% CI, 1.783-3.335). Although there was no statistical significance, tumors >2 cm were less likely to be palpable in obese patients than in patients of normal weight (nonpalpable in 33.8% and 27.0%, respectively).

CONCLUSION

Our study suggests that obesity is associated with a more advanced breast cancer stage, which represents a poor prognosis, and large tumors tend to be less palpable in women with obesity.

The effect of bariatric surgery on breast cancer incidence and characteristics: A meta-analysis and systematic review

BACKGROUND

Obesity is a major risk factor for breast cancer. This study examines whether bariatric surgery affects breast cancer incidence in women with obesity compared to BMI-matched controls.

METHODS

EMBASE, MEDLINE, Web of Science, and CINAHL were searched. Primary studies on female breast cancer incidence after bariatric surgery were eligible.

RESULTS

11 studies were included (n = 1,106,939). The rate of cancer diagnosis was lower in the surgical group (0.54%) compared to control (0.84%; risk ratio (RR) 0.50, 95%CI 0.37-0.67, I² = 88%). The results were robust to sensitivity analyses for patient age and study size. Bariatric surgery was associated with increased risk of stage I cancer (RR 1.23, 95%CI 1.06-1.44) and reduced risk of stage III or IV cancer (RR 0.50, 95%CI 0.28-0.88). Hormone receptor characteristics were not affected.

CONCLUSIONS

Bariatric surgery is associated with reduced incidence and earlier stage at diagnosis of breast cancer in women with obesity compared to BMI-matched controls.

Role of dietary fat on obesity-related postmenopausal breast cancer: insights from mouse models and methodological considerations

The increasing incidence rate of breast cancer in the last few decades is known to be linked to the upward trend of obesity prevalence worldwide. The consumption of high-fat diet in particular has been correlated with postmenopausal breast cancer risk. The underlying mechanisms, using suitable and reliable experimental mouse model, however, is lacking. The current review aims to discuss the evidence available from mouse models on the effects of dietary fats intake on postmenopausal breast cancer. We will further discuss the biochemical mechanisms involved in the occurrence of postmenopausal breast cancer. In addition, the methodological considerations and their limitations in obesity-related postmenopausal breast cancer, such as choice of mouse models and breast cancer cell lines as well as the study duration will be reviewed. The current review will provide a platform for further development of new xenograft models which may offer the opportunity to investigate the mechanisms of postmenopausal breast cancer in a greater detail.

Insulin/IGF Axis in Breast Cancer: Clinical Evidence and Translational Insights

Background: Breast cancer (BC) is the most common neoplasm in women. Many clinical and preclinical studies investigated the possible relationship between host metabolism and BC. Significant differences among BC subtypes have been reported for glucose metabolism. Insulin can promote tumorigenesis through a direct effect on epithelial tissues or indirectly by affecting the levels of other modulators, such as the insulin-like growth factor (IGF) family of receptors, sex hormones, and adipokines. The potential anti-cancer activity of metformin is based on two principal effects: first, its capacity for lowering circulating insulin levels with indirect endocrine effects that may impact on tumor cell proliferation; second, its direct influence on many pro-cancer signaling pathways that are key drivers of BC aggressiveness. Methods: In the present review, the interaction between BC, host metabolism, and patients’ prognosis has been reviewed across available literature evidence. Conclusions: Obesity, metabolic syndrome, and insulin resistance are all involved in BC growth and could have a relevant impact on prognosis. All these factors act through a pro-inflammatory state, mediated by cytokines originated in fat tissue, and seem to be related to a higher risk of BC development and worse prognosis.

The Global, Regional, and National Burden and Trends of Breast Cancer From 1990 to 2019: Results From the Global Burden of Disease Study 2019

BACKGROUND

The burden of breast cancer has been increasing globally. The epidemiology burden and trends need to be updated. This study aimed to update the burden and trends of breast cancer incidences, deaths, and disability-adjusted life-years (DALYs) from 1990 to 2019, using the Global Burden of Disease 2019 study.

METHODS

The data of incidences, deaths, DALYs, and age-standardized rates were extracted. Estimated annual percentage changes were used to quantify the trends of age-standardized rates. Besides, the population attributable fractions of the risk factors of breast cancer were also estimated.

RESULTS

Globally, the incidences of breast cancer increased to 2,002,354 in 2019. High social-development index (SDI) quintiles had the highest incidence cases with a declining trend in age-standardized incidence rate. In 2019, the global deaths and DALYs of breast cancer increased to 700,660 and 20,625,313, respectively. From 1990 to 2019, the age-standardized mortality rates and age-standardized DALY rates declined globally, especially in high and high-middle SDI quintiles. Besides, the trends varied from different regions and countries. The proportion of the patients in the 70+ years age group increased globally. Deaths of breast cancer attributable to high fasting plasma glucose and high body mass index increased globally, and high fasting plasma glucose was the greatest contributor to the global breast cancer deaths.

CONCLUSION

The burden of breast cancer in higher SDI quintiles had gone down while the burden was still on the rise in lower SDI quintiles. It is necessary to appeal to the public to decrease the exposure of the risk factors.

Determinants of screening methods utilization among Iraq/Sulaimani women

PURPOSE

This study aims to find out the participation rate of women in the utilization of screening methods to determine the relationship of sociodemographic health characteristics and breast cancer (BC) awareness with the utilization of screening methods. The authors' study aims to examine the relationship between women's belief and the utilization of screening methods.

DESIGN/METHODOLOGY/APPROACH

A cross-sectional study was conducted in three health centers from December 13, 2016 to June 12, 2017. A questionnaire was constructed for data collection about sociodemographic characteristics, screening awareness and medical and health background variables. Additionally, BC awareness measure and champion health belief model scales were used to measure women's perceptiveness about BC.

FINDINGS

Despite the awareness among 78.9% of women regarding clinical breast examination (CBE) as a screening method, only 9.5% women utilized it for screening. Due to prescription by physicians for diagnosis of BC, 23.6% women had done mammography at least once in their life. Having jobs and a good education significantly influenced the utilization of CBE as a screening method. The logistic regression analysis found that old age, family history of BC, good knowledge about BC, perceived susceptibility, low rate of perceived barriers to mammography and CBE predicted participation in screening.

ORIGINALITY/VALUE

Enhancing knowledge about BC and screening, emphasizing the susceptibility to BC and the benefits of screening will help in better participation. Importance should be given to illiterate and unemployed women.

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.

Nutrition and Breast Cancer Research in Arab Countries: Gaps, Opportunities, and Recommendations

According to the WHO, Arab countries have the highest relative increase in Breast Cancer (BC) rates worldwide. Current shifts in dietary patterns in these countries are postulated as important modifiable risk factors of the disease. The objectives of this review were to examine the gaps and opportunities in the extent, range and nature of nutrition-related BC research in Arab countries. Studies (n = 286) were identified through searching 14 electronic databases. Among the gaps identified were limited international collaborations, preponderance of laboratory-based research at the expense of population-based research, focus on single supplement/nutrient/food research, limited use of dietary assessment tools, and studying nutrition in isolation of other environmental factors. Despite these gaps, several opportunities appeared. The distribution of papers among Arab countries suggested that collaboration between high and middle income countries could create a positive synergy between research expertise and wealth. In addition, the steady increase in the number of articles published during the last two decades reflected a promising momentum in nutrition and BC research in the Arab world. These gaps and opportunities constituted context-specific evidence to orient nutrition and BC research in Arab countries which could ultimately lead to development of effective interventions for prevention of BC in these countries.

Body mass index increases the lymph node metastasis risk of breast cancer: a dose-response meta-analysis with 52904 subjects from 20 cohort studies

Background

Since body mass index (BMI) is a convincing risk factor for breast cancer, it is speculated to be associated with lymph node metastasis. However, epidemiological studies are inconclusive. Therefore, this study was conducted to investigate the effect of BMI on the lymph node metastasis risk of breast cancer.

Methods

Cohort studies that evaluating BMI and lymph node metastasis in breast cancer were selected through various databases including PubMed, PubMed Central (PMC), Web of science, the China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals (VIP) and Wanfang Data Knowledge Service Platform (WanFang) until November 30, 2019. The two-stage, random effect meta-analysis was performed to assess the dose-response relationship between BMI and lymph node metastasis risk. Between-study heterogeneity was assessed using I². Subgroup analysis was done to find possible sources of heterogeneity.

Results

We included a total of 20 studies enrolling 52,904 participants. The summary relative risk (RR) (1.10, 95%CI: 1.06–1.15) suggested a significant effect of BMI on the lymph node metastasis risk of breast cancer. The dose-response meta-analysis (RR = 1.01, 95%CI: 1.00–1.01) indicated a positive linear association between BMI and lymph node metastasis risk. For every 1 kg/m² increment of BMI, the risk of lymph node metastasis increased by 0.89%. In subgroup analyses, positive linear dose-response relationships between BMI and lymph node metastasis risk were observed among Asian, European, American, premenopausal, postmenopausal, study period less than 5 years, and more than 5 years groups. For every 1 kg/m² increment of BMI, the risk of lymph node metastasis increased by 0.99, 0.85, 0.61, 1.44, 1.45, 2.22, and 0.61%, respectively.

Conclusion

BMI significantly increases the lymph node metastasis risk of breast cancer as linear dose-response reaction. Further studies are needed to identify this association.

Epithelial-Mesenchymal Transition Programs and Cancer Stem Cell Phenotypes: Mediators of Breast Cancer Therapy Resistance

Epithelial-mesenchymal transition (EMT) programs play essential functions in normal morphogenesis and organogenesis, including that occurring during mammary gland development and glandular regeneration. Historically, EMT programs were believed to reflect a loss of epithelial gene expression signatures and morphologies that give way to those associated with mesenchymal cells and their enhanced migratory and invasive behaviors. However, accumulating evidence now paints EMT programs as representing a spectrum of phenotypic behaviors that also serve to enhance cell survival, immune tolerance, and perhaps even metastatic dormancy. Equally important, the activation of EMT programs in transformed mammary epithelial cells not only enhances their acquisition of invasive and metastatic behaviors, but also expands their generation of chemoresistant breast cancer stem cells (BCSC). Importantly, the net effect of these events results in the appearance of recurrent metastatic lesions that remain refractory to the armamentarium of chemotherapies and targeted therapeutic agents deployed against advanced stage breast cancers. Here we review the molecular and cellular mechanisms that contribute to the pathophysiology of EMT programs in human breast cancers and how these events impact their "stemness" and acquisition of chemoresistant phenotypes.

The Association between Obesity and Premenopausal Breast Cancer According to Intrinsic Subtypes - a Systematic Review

Introduction Obesity is a well-established risk factor for postmenopausal hormone-receptor positive breast cancer. The relationship between premenopausal breast cancer intrinsic subtypes and obesity is not completely elucidated; therefore, this systematic review was conducted to give an overview about the existing evidence. Methods This review followed the PRISMA Statement for Systematic Reviews and Meta-analyses. Full electronic search was conducted in PubMed and Orbis for articles published in English between January 2008 and June 2018. The literature search was performed in June 2018 using search strings that combined the Medical Subject Headings (MeSH terms) keywords and/or text words in any field were used: "body mass index" (BMI) OR obesity OR overweight AND premenopausal breast cancer. Results 391 articles were found to be eligible, of which ultimately 21 were included comprising a total of 55 580 breast cancer patients. 45% were case-control studies, 35% were single cohort studies, 15% were cohort studies, two were cross-sectional studies, one was a multicenter-study and one was a pooled analysis. The evidence shows a tendency for an increased risk for the more aggressive triple negative breast cancer subtype in obese premenopausal women and a decreased risk for less aggressive tumor subtypes such as the luminal A subtype. The evidence is limited by small sample sizes for triple negative and HER2-positive subtypes in severely obese patients. Conclusion Higher BMI might influence aggressive tumor characteristics among premenopausal women and has divergent impacts on the risk of different breast cancer subtypes. Further research is needed to confirm these results and to evaluate potential pathophysiologic mechanisms for the relationship between obesity and aggressive premenopausal breast cancer subtypes.

Weighing the Risk: effects of Obesity on the Mammary Gland and Breast Cancer Risk

Obesity is a preventable risk factor for breast cancer following menopause. Regardless of menopausal status, obese women who develop breast cancer have a worsened prognosis. Breast tissue is comprised of mammary epithelial cells organized into ducts and lobules and surrounded by adipose-rich connective tissue. Studies utilizing multiple in vivo models of obesity as well as human breast tissue have contributed to our understanding of how obesity alters mammary tissue. Localized changes in mammary epithelial cell populations, elevated secretion of adipokines and angiogenic mediators, inflammation within mammary adipose tissue, and remodeling of the extracellular matrix may result in an environment conducive to breast cancer growth. Despite these significant alterations caused by obesity within breast tissue, studies have suggested that some, but not all, obesity-induced changes may be mitigated with weight loss. Here, we review our current understanding regarding the impact of obesity on the breast microenvironment, how obesity-induced changes may contribute to breast tumor progression, and the impact of weight loss on the breast microenvironment.

Obesity reduces mammary epithelial cell TGFβ1 activity through macrophage-mediated extracellular matrix remodeling

Obesity is a risk factor for breast cancer in postmenopausal and high‐risk premenopausal women. Changes within the obese breast microenvironment may increase breast cancer risk. Transforming growth factor beta‐1 (TGFβ1) is a major regulator of mammary epithelial stem/progenitor cells, and its activity is dysregulated under conditions of obesity. Using a high‐fat diet model of obesity in mice and breast tissue from women, we observed that TGFβ1 activity is reduced in breast epithelial cells in obesity. Breast ducts and lobules demonstrated increased decorin in the extracellular matrix (ECM) surrounding epithelial cells, and we observed that decorin and latent TGFβ1 complexed together. Under conditions of obesity, macrophages expressed higher levels of decorin and were significantly increased in number surrounding breast epithelial cells. To investigate the relationship between macrophages and decorin expression, we treated obese mice with either IgG control or anti‐F4/80 antibodies to deplete macrophages. Mice treated with anti‐F4/80 antibodies demonstrated reduced decorin surrounding mammary ducts and enhanced TGFβ1 activity within mammary epithelial cells. Given the role of TGFβ1 as a tumor suppressor, reduced epithelial TGFβ1 activity and enhanced TGFβ1 within the ECM of obese mammary tissue may enhance breast cancer risk.

Microbiome, bile acids, and obesity: How microbially modified metabolites shape anti-tumor immunity

Bile acids (BAs) are known facilitators of nutrient absorption but recent paradigm shifts now recognize BAs as signaling molecules regulating both innate and adaptive immunity. Bile acids are synthesized from cholesterol in the liver with subsequent microbial modification and fermentation adding complexity to pool composition. Bile acids act on several receptors such as Farnesoid X Receptor and the G protein-coupled BA receptor 1 (TGR5). Interestingly, BA receptors (BARs) are expressed on immune cells and activation either by BAs or BAR agonists modulates innate and adaptive immune cell populations skewing their polarization toward a more tolerogenic anti-inflammatory phenotype. Intriguingly, recent evidence also suggests that BAs promote anti-tumor immune response through activation and recruitment of tumoricidal immune cells such as natural killer T cells. These exciting findings have redefined BA signaling in health and disease wherein they may suppress inflammation on the one hand, yet promote anti-tumor immunity on the other hand. In this review, we provide our readers with the most recent understanding of the interaction of BAs with the host microbiome, their effect on innate and adaptive immunity in health and disease with a special focus on obesity, bariatric surgery-induced weight loss, and immune checkpoint blockade in cancer.

Impact of Obesity on Clinicopathologic Characteristics and Disease Prognosis in Pre- and Postmenopausal Breast Cancer Patients: A Retrospective Institutional Study

PURPOSE

To investigate the association between obesity and breast cancer clinicopathologic characteristics at presentation along with prognostic impact among Jordanian breast cancer patients. Such data are lacking in Arabian countries.

METHODS

In this retrospective study, 348 breast cancer patients were included. Analyses were conducted for associations between body mass index (BMI) and age at diagnosis, tumor clinicopathologic characteristics, and molecular subtypes. Eight prognostic factors were considered, and total prognostic scores were calculated. The analysis was stratified by menopausal status. Multivariate logistic stepwise regression analysis was conducted to identify predictors for breast cancer recurrence and death.

RESULTS

Mean age at diagnosis was 50.98 ± 10.96 years. Mean BMI at diagnosis was 29.52 ± 5.32 kg/m². Mean age at diagnosis was significantly higher for overweight and obese patients compared to underweight/normal patients (P < 0.001). A significant positive correlation was observed between patient age and BMI at diagnosis (r = 0.251, P < 0.001). Grade of carcinoma was significantly correlated with BMI in the whole population examined (P=0.003). Obese breast cancer patients had significantly higher prognostic scores compared to nonobese cases, indicating worse prognostic features at presentation (P=0.034). Stratification of data analysis based on menopausal status revealed significant associations between obesity and each of tumor stage and grade among postmenopausal but not premenopausal patients (P=0.019 and P=0.031, respectively). Similarly, postmenopausal obese patients had significantly higher prognostic scores compared to nonobese counterparts (P=0.007), indicating worse prognosis, a finding which was also absent among premenopausal breast cancer patients. No significant association between BMI with expression status of hormone receptors, HER2, lymphovascular invasion, and molecular subtypes was found among patients. BMI was a significant predictor for disease recurrence in which obese breast cancer patients had greater odds (2-fold) to develop locoregional and distant recurrence compared to nonobese cases (P=0.011).

CONCLUSIONS

Obesity was associated with advanced stage and grade of breast carcinoma at diagnosis. The impact of BMI on clinicopathologic characteristics and prognosis was confined to postmenopausal cases. Jordanian obese breast cancer patients are at greater risk of breast cancer recurrence and reduced survival compared to their nonobese counterparts.

Correlation of BMI with breast cancer subtype and tumour size

Background

Breast cancer is a heterogeneous disease which is divided broadly into luminal, HER2 and basal type based on molecular profiling. Increased body mass index (BMI) has been associated with the risk of developing breast cancer but the association based on molecular subtype remains conflicting.

Methods

This was an observational study carried out over a period of 2 years. Nonmetastatic breast cancer patients were evaluated for the tumour subtype based on surrogate markers (ER, PR and HER2). The BMI of these patients was correlated with the tumour subtype and size.

Results

We studied 476 patients with breast cancer with the median age of 46 years (range, 25–86) and 58% were premenopausal. The mean BMI of the cohort was 24.1, which was significantly higher in postmenopausal women (24.9 versus 23.6, p < 0.05). Overall, only 10% of patients were obese. The mean BMI in the luminal, HER2 and TNBC subtypes was 24.7, 22.4 and 23.9, respectively (p < 0.01). Also, the mean tumour size in luminal, HER2 and TNBC subtype was 4.02, 3.80 and 4.27 cm, respectively (p = 0.158).

Conclusion

The average BMI was higher in patients with luminal subtype followed by TNBC and lowest for HER2 at the time of diagnosis. The mean tumour size was numerically higher for TNBC and lowest for HER2 subtype although the difference was not statistically significant. Larger studies may provide clarity of association between the BMI and tumour subtype.

Adipocyte/breast cancer cell crosstalk in obesity interferes with the anti-proliferative efficacy of tamoxifen

Background

Obesity is a well-known risk factor of breast cancer in post-menopausal women that also correlates with a diminished therapeutic response. The influence of adipocytes and their secretome, i.e. adipokines, on the efficacy of hormone therapy has yet to be elucidated.

Methods

We investigated, ex vivo, whether mature adipocytes, differentiated from adipose stem cells of normal-weight (MA20) or obese (MA30) women, and their secretions, were able to counteract the effects of tamoxifen (Tx) which is known to decrease neoplastic cell proliferation.

Results

In a tridimensional model and in a model of co-culture, the anti-proliferative effect of Tx on MCF-7 cancer cells was counteracted by MA30. These two models highlighted two different specific gene expression profiles for genes encoding cytokines or involved in angiogenesis based on the adipocyte microenvironment and the treatment. Thus it notably showed altered expression of genes such as TNFα that correlated with IL-6. In addition, leptin, IL-6 and TNFα, at concentrations reflecting plasma concentrations in obese patients, decreased the anti-proliferative efficacy of 4-hydroxytamoxifen (a major active metabolite of Tx).

Conclusions

These findings bring insights on adipocytes and mammary cancer cell interactions in Tx therapy, particularly in overweight/obese people. Indeed, patient’ adipokine status would give valuable information for developing individual strategies and avoid resistance to treatment.

Contribution of Adipose Tissue to Development of Cancer

Solid tumor growth and metastasis require the interaction of tumor cells with the surrounding tissue, leading to a view of tumors as tissue-level phenomena rather than exclusively cell-intrinsic anomalies. Due to the ubiquitous nature of adipose tissue, many types of solid tumors grow in proximate or direct contact with adipocytes and adipose-associated stromal and vascular components, such as fibroblasts and other connective tissue cells, stem and progenitor cells, endothelial cells, innate and adaptive immune cells, and extracellular signaling and matrix components. Excess adiposity in obesity both increases risk of cancer development and negatively influences prognosis in several cancer types, in part due to interaction with adipose tissue cell populations. Herein, we review the cellular and noncellular constituents of the adipose "organ," and discuss the mechanisms by which these varied microenvironmental components contribute to tumor development, with special emphasis on obesity. Due to the prevalence of breast and prostate cancers in the United States, their close anatomical proximity to adipose tissue depots, and their complex epidemiologic associations with obesity, we particularly highlight research addressing the contribution of adipose tissue to the initiation and progression of these cancer types. Obesity dramatically modifies the adipose tissue microenvironment in numerous ways, including induction of fibrosis and angiogenesis, increased stem cell abundance, and expansion of proinflammatory immune cells. As many of these changes also resemble shifts observed within the tumor microenvironment, proximity to adipose tissue may present a hospitable environment to developing tumors, providing a critical link between adiposity and tumorigenesis. © 2018 American Physiological Society. Compr Physiol 8:237-282, 2018.

Obesity reversibly depletes the basal cell population and enhances mammary epithelial cell estrogen receptor alpha expression and progenitor activity

Background

Obesity is correlated with an increased risk for developing postmenopausal breast cancer. Since obesity rates continue to rise worldwide, it is important to understand how the obese microenvironment influences normal mammary tissue to increase breast cancer risk. We hypothesized that obesity increases the proportion of luminal progenitor cells, which are thought to be the cells of origin for the most common types of breast cancer, potentially leading to an increased risk for breast cancer.

Methods

To study the obese microenvironment within the mammary gland, we used a high-fat diet mouse model of obesity and human breast tissue from reduction mammoplasty surgery. We identified changes in breast epithelial cell populations using flow cytometry for cell surface markers, in vitro functional assays and expression of markers on breast tissue sections.

Results

In both obese female mice and women, mammary epithelial cell populations demonstrated significant decreases in basal/myoepithelial cells, using either flow cytometry or cell-type-specific markers (SMA and p63). Estrogen receptor alpha (ERα) expression was significantly increased in luminal cells in obese mammary tissue, compared with control mice or breast tissue from lean women. Functional assays demonstrated significantly enhanced mammary epithelial progenitor activity in obese mammary epithelial cells and elevated numbers of ERα-positive epithelial cells that were co-labeled with markers of proliferation. Weight loss in a group of obese mice reversed increases in progenitor activity and ERα expression observed in obese mammary tissue.

Conclusions

Obesity enhances ERα-positive epithelial cells, reduces the number of basal/myoepithelial cells, and increases stem/progenitor activity within normal mammary tissue in both women and female mice. These changes in epithelial cell populations induced by obesity are reversible with weight loss. Our findings support further studies to examine how obesity-induced changes in stem/progenitor cells impact breast tumor incidence and histologic tumor types.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-017-0921-7) contains supplementary material, which is available to authorized users.

Body mass index, age at breast cancer diagnosis, and breast cancer subtype: a cross-sectional study

PURPOSE

Evidence suggests that premenopausal obesity decreases and postmenopausal obesity increases breast cancer risk. Because it is not well known whether this is subtype dependent, we studied the association between body mass index (BMI) and age at breast cancer diagnosis, or the probability of being diagnosed with a specific breast cancer phenotype, by menopausal status.

METHODS

All patients with non-metastatic operable breast cancer from the University Hospital Leuven diagnosed between January 1, 2000 and December 31, 2013 were included (n = 7020) in this cross-sectional study. Linear models and logistic regression were used for statistical analysis. Allowing correction for age-related BMI-increase, we used the age-adjusted BMI score which equals the difference between a patient's BMI score and the population-average BMI score corresponding to the patient's age category.

RESULTS

The quadratic relationship between the age-adjusted BMI and age at breast cancer diagnosis (p = 0.0207) interacted with menopausal status (p < 0.0001); increased age at breast cancer diagnosis was observed with above-average BMI scores in postmenopausal women, and with below-average BMI scores in premenopausal women. BMI was linearly related to the probabilities of Luminal B and HER2-like breast cancer phenotypes, but only in postmenopausal women. The relative changes in probabilities between both these subtypes mirrored each other.

CONCLUSION

BMI associates differently before and after menopause with age at breast cancer diagnosis and with the probability that breast cancer belongs to a certain phenotype. The opposite effect of increasing BMI on relative frequencies of Luminal B and HER2-like breast cancers suggests a common origin.

Breast Cancer Epidemiology and Risk Factors

Between the years 2010 and 2012, the lifetime probability of developing female breast cancer was 12.3%, or approximately 1 in 8. Worldwide, breast cancer is the most common cancer in women. Survival is increasing. Between 2005 and 2011, the 5-year relative survival was found to be 89%. This is thought to be due to both the increase in utilization of population-wide screening, as well as advances in treatment. Less than 10% of breast cancers can be attributed to an inherited genetic mutation. Breast cancer is more commonly associated with environmental, reproductive, and lifestyle factors, some of which are potentially modifiable.

Obesity and Prognostic Variables in Colombian Breast Cancer Patients: A Cross-Sectional Study

Introduction

Obesity is an established risk factor for cancer and cancer-related deaths, including that of the breast. While the prevalence of female obesity has accelerated over the past decade in many developing countries, such as Colombia, the prevalence of overweight and obesity specifically in breast cancer populations has not been fully described.

Methods

A cross-sectional study including 849 women diagnosed with breast cancer between 2009 and 2014. Based on body mass index, prevalence of overweight (BMI ≥ 25 < 30) and obesity (BMI ≥ 30) and associations of BMI with clinical and tumor histopathological features were analyzed.

Results

Colombian breast cancer patients had a prevalence of overweight of 34.28% and obesity of 28.15%. Mean BMI was comparable between premenopausal and postmenopausal women (27.2 versus 27.7, resp.). Among premenopausal women, higher BMI was significantly positively associated with hormone receptor negative tumors, as well as with greater lymphovascular invasion.

Conclusions

Colombian breast cancer patients exhibit a significant prevalence of overweight and obesity. Associations of high BMI and poor prognosis variables in the premenopausal population suggest risk of aggressive disease in this population. Future studies to further validate our observations are warranted in order to implement multidisciplinary clinical guidelines.

Leptin signals via TGFB1 to promote metastatic potential and stemness in breast cancer

Epidemiological studies have shown obesity to be linked with poorer outcomes in breast cancer patients. The molecular mechanisms responsible for the increased risk of invasive/metastatic disease with obesity are complex, but may include elevated levels of adipokines such as leptin. Using physiological levels of leptin found in obesity in a novel chronic in vitro treatment model (≤200 ng/ml for 14 days), we confirmed the occurrence of leptin-mediated changes in growth, apoptosis and metastatic behavior, and gene expression changes representing epithelial-to-mesenchymal transition (EMT) and a cancer stem cell (CSC) like phenotype in breast epithelial and cancer cell lines (MCF10A, MCF10AT1, MCF7 and MDA-MB-231). Further, we have discovered that these effects were accompanied by increased expression of TGFB1, and could be significantly reduced by co-treatment with neutralizing antibody against TGFB1, indicating that the induction of these characteristics was mediated via TGFB1. Occurring in both MCF7 and MCF10AT1 cells, it suggests these actions of leptin to be independent of estrogen receptor status. By linking leptin signalling to the established TGFB1 pathway of metastasis / EMT, this study gives a direct mechanism by which leptin can contribute to the poorer outcomes of obese cancer patients. Inhibitors of TGFB1 are in currently in phase III clinical trials in other malignancies, thus identifying the connection between leptin and TGFB1 will open new therapeutic opportunities for improving outcomes for obese breast cancer patients.

Comparative Effect of Initiating Metformin Versus Sulfonylureas on Breast Cancer Risk in Older Women

BACKGROUND

Several observational studies have reported that metformin may be associated with reduced risk of breast cancer; however, many of these studies were affected by time-related biases such as immortal time bias and time-window bias. This study aimed to examine the relative risk of breast cancer for older women initiating metformin versus sulfonylureas while avoiding such biases.

METHODS

The study cohort consisted of women aged 65+ who initiated monotherapy with metformin (n = 45,900) or sulfonylureas (n = 13,904) and were free of cancer and renal disease within 6 months before treatment initiation using 2007-2012 US Medicare claims data. We followed treatment initiators for incident breast cancer, and estimated hazard ratios using weighted Cox models. Unmeasured confounding by body mass index and smoking was further adjusted by propensity score calibration using external information from Medicare Current Beneficiary Survey 2006-2009 panels.

RESULTS

During 58,835 and 16,366 person-years of follow-up, 385 initiators of metformin treatment and 95 of sulfonylurea were diagnosed with breast cancer. Metformin initiators did not have a reduced risk of breast cancer compared with sulfonylurea initiators (hazard ratio: 1.2; 95% confidence interval: 0.94, 1.6). Externally controlling for body mass index and smoking did not affect the estimates.

CONCLUSION

The findings of this study provide no support for a reduced risk of breast cancer after initiation of metformin compared with a clinical alternative in older women. This study is limited by the relatively short follow-up time and we cannot exclude the possible benefits of long-time metformin use on breast cancer risk.

Leptin signaling and cancer chemoresistance: Perspectives

Obesity is a major health problem and currently is endemic around the world. Obesity is a risk factor for several different types of cancer, significantly promoting cancer incidence, progression, poor prognosis and resistance to anti-cancer therapies. The study of this resistance is critical as development of chemoresistance is a serious drawback for the successful and effective drug-based treatments of cancer. There is increasing evidence that augmented adiposity can impact on chemotherapeutic treatment of cancer and the development of resistance to these treatments, particularly through one of its signature mediators, the adipokine leptin. Leptin is a pro-inflammatory, pro-angiogenic and pro-tumorigenic adipokine that has been implicated in many cancers promoting processes such as angiogenesis, metastasis, tumorigenesis and survival/resistance to apoptosis. Several possible mechanisms that could potentially be developed by cancer cells to elicit drug resistance have been suggested in the literature. Here, we summarize and discuss the current state of the literature on the role of obesity and leptin on chemoresistance, particularly as it relates to breast and pancreatic cancers. We focus on the role of leptin and its significance in possibly driving these proposed chemoresistance mechanisms, and examine its effects on cancer cell survival signals and expansion of the cancer stem cell sub-populations.

Can we use gonadotropin plasma concentration as surrogate marker for BMI-related incomplete estrogen suppression in breast cancer patients receiving anastrozole?

BACKGROUND

BMI has been suggested to impact on estrogenic activity in patients receiving anastrozole resulting in a reduced treatment efficacy in obese women. Current evidence in this regard is controversially discussed. Since estradiol is inversely correlated with gonadotropins it can be assumed that an impact of BMI is also reflected by gonadotropin plasma concentrations. We aim at investigating the impact of BMI on the hormonal state of breast cancer (BC) patients receiving anastrozole indicated by LH, FSH and SHBG as well as estradiol.

METHODS

We determined gonadotropin-, estradiol- and anastrozole- serum concentrations from postmenopausal, early stage breast cancer patients receiving upfront anastrozole within routine after care. Gonadotropin plasma concentrations were derived from the routine laboratory examination report. A liquid chromatography tandem mass spectrometry method was used for the measurement of anastrozole serum concentrations. BMI was assessed within the routine after-care check-up.

RESULTS

The overall sample comprised 135 BC patients with a mean age of 65.3 years. BMI was significantly correlated with LH, FSH and SHBG. This association was neither influenced by age nor by anastrozole serum concentrations according to the regression model. Despite aromatase inhibition 12% of patients had detectable estrogen levels in routine quantification.

CONCLUSION

Obese women have an altered hormonal situation compared to normally weight women under the same dose of anastrozole. Our study findings are a further indicator for the relevance of BMI in regard of anastrozole metabolism and possible estrogenic activity indicated by gonadotropin plasma level.

[Outcomes of patients with breast cancer in function of their body mass index]

OBJECTIVE

The aim of this study was to evaluate outcomes of patients with breast cancer in function of the body mass index (BMI).

METHODS

The study cohort consisted of consecutive women undergoing surgery for breast cancer in our institution between January 2009, and September 2013. Individual records of all patients were reviewed and analyzed. Patient BMI was categorized as underweight, normal, overweight and obese.

RESULTS

A total of 1599 patients were evaluated. Patients were followed for one to 265months with a mean of 36.4months. The number of patients in each of the BMI categories was 66, 779, 463 and 291 for underweight, normal, overweight and obese women respectively. Women with higher BMI were more frequently affected by hypertension (18, 21, 35 and 47% respectively, P<0.0001) and diabetes (3, 2, 7 and 7% respectively, P<0.0001). Obese women had more frequently an inflammatory presentation (P=0.006), larger tumour size (P=0.038) and axillary lymph node involvement (P=0.03) with much more positive lymph nodes (P=0.02). Patients had the same protocols of treatment (surgery and adjuvant treatment). There was no statistically significant difference in overall 5-years survival between groups (P=0.30).

CONCLUSIONS

Our study demonstrate a more aggressive clinical and histological presentation for obese women with breast cancer.

Interaction of MRE11 and Clinicopathologic Characteristics in Recurrence of Breast Cancer: Individual and Cumulated Receiver Operating Characteristic Analyses

The interaction between the meiotic recombination 11 homolog A (MRE11) oncoprotein and breast cancer recurrence status remains unclear. The aim of this study was to assess the interaction between MRE11 and clinicopathologic variables in breast cancer. A dataset for 254 subjects with breast cancer (220 nonrecurrent and 34 recurrent) was used in individual and cumulated receiver operating characteristic (ROC) analyses of MRE11 and 12 clinicopathologic variables for predicting breast cancer recurrence. In individual ROC analysis, the area under curve (AUC) for each predictor of breast cancer recurrence was smaller than 0.7. In cumulated ROC analysis, however, the AUC value for each predictor improved. Ten relevant variables in breast cancer recurrence were used to find the optimal prognostic indicators. The presence of any six of the following ten variables had a high (79%) sensitivity and a high (70%) specificity for predicting breast cancer recurrence: tumor size ≥ 2.4 cm, tumor stage II/III, therapy other than hormone therapy, age ≥ 52 years, MRE11 positive cells > 50%, body mass index ≥ 24, lymph node metastasis, positivity for progesterone receptor, positivity for epidermal growth factor receptor, and negativity for estrogen receptor. In conclusion, this study revealed that these 10 clinicopathologic variables are the minimum discriminators needed for optimal discriminant effectiveness in predicting breast cancer recurrence.