Metabolic syndrome-breast cancer link varies by intrinsic molecular subtype

Breast cancer stage and molecular subtype distribution: real-world insights from a regional oncological center in Hungary

OBJECTIVE

Examining the distribution of breast cancer (BC) stage and molecular subtype among women aged below (< 45 years), within (45-65 years), and above (> 65 years) the recommended screening age range helps to understand the screening program's characteristics and contributes to enhancing the effectiveness of BC screening programs.

METHODS

In this retrospective study, female patients with newly diagnosed BC from 2010 to 2020 were identified. The distribution of cases in terms of TNM stages, severity classes, and subtypes was analysed according to age groups.

RESULTS

A total of 3282 women diagnosed with BC were included in the analysis. Among these cases 51.4% were detected outside the screening age group, and these were characterized by a higher TNM stage compared to those diagnosed within the screening age band. We observed significantly higher relative frequency of advanced BC in the older age group compared to both the screening age population and women younger than 45 years (14.9% vs. 8.7% and 7.7%, P < 0.001). HR-/HER2- and HER+ tumours were relatively more frequent among women under age 45 years (HR-/HER2-: 23.6%, HER2+: 20.5%) compared to those within the screening age range (HR-/HER2-: 13.4%, HER2+: 13.9%) and the older age group (HR-/HER2-: 10.4%, HER2+: 11.5%).

CONCLUSIONS

The findings of our study shed light on potential areas for the improvement of BC screening programs (e.g., extending screening age group, adjusting screening frequency based on molecular subtype risk status) in Hungary and internationally, as well.

Metabolic Syndrome and Breast Cancer Molecular Subtypes: An Observational Patient Study

Background:

Breast cancer molecular subtypes share various prognostic profiles, and luminal A molecular subtypes have a better prognosis compared with other molecular subtypes. However, whether metabolic syndrome or individual risk factors of metabolic syndrome influence on the development of molecular subtype remains elusive. We aimed to assess the association between metabolic syndrome risk factors and breast cancer molecular subtypes among patients with metabolic syndrome in a clinical setting.

Methods:

In total, 101 breast cancer patients with mean age, 58.4 ± 8.5 years, and overt metabolic syndrome prospectively were recruited. Immunohistochemistry procedure was used to determine molecular subtypes. Assessment of clinical, biochemical, and anthropometric parameters was performed. Logistic regression analysis was used to assess the relationship between risk factors and breast cancer molecular subtypes categories. A similar approach was used to assess the relation between breast cancer molecular subtypes and menopause.

Results:

Comparison of metabolic syndrome individual risk factors according to breast cancer molecular subtypes no statistical difference was found for systolic (P = .33) and diastolic blood pressure (P = .17), fasting glucose (P = .77), triglycerides (P = .62), high-density lipoprotein (P = .33), body mass index (P = .87), and waist circumference (P = .81). A positive trend was found between high-density lipoprotein and HER2+. No association was found with other risk factors. Moreover, an association was found between HER2+ categories and menopause.

Conclusion:

In breast cancer patients with metabolic syndrome, we observed an increased trend between high-density lipoprotein and HER2+ molecular subtype, suggesting that underlying dyslipidemia may favor poor prognosis. HER2+ was associated with menopause which may influence further expression of HER2+ .

Metabolic Syndrome and Risk of Breast Cancer by Molecular Subtype: Analysis of the MEND Study

Metabolic syndrome is a cluster of biological irregularities that is a known risk factor for cardiovascular disease, stroke, and diabetes. In a case-control study of 555 West African women, we observed that metabolic syndrome was strongly associated with breast cancer and the aggressive triple-negative molecular subtype, highlighting a need for clinical and lifestyle interventions targeting metabolic syndrome to reduce breast cancer risk in this population.

Collaborative Molecular Epidemiology Study of Metabolic Dysregulation, DNA Methylation, and Breast Cancer Risk Among Nigerian Women: MEND Study Objectives and Design

PURPOSE

To elucidate the role of metabolic dysregulation and associated DNA methylation changes on breast cancer risk and aggressive subtypes among Nigerian women. We describe the design and methods of a collaborative molecular epidemiology study of breast cancer in Nigerian hospitals.

METHODS

The Mechanisms for Novel and Established Risk Factors for Breast Cancer in Women of Nigerian Descent (MEND) study was designed as a matched case-control study of 350 patients, age 18 to 75 years, with newly diagnosed, treatment-naïve breast cancer and 350 age-matched healthy controls from surrounding geographic areas. Patients with breast cancer seen for initial diagnosis at four large tertiary hospitals in southwest Nigeria and one affiliated private hospital were recruited. Healthy female controls were selected from a cohort of 4,000 healthy women recruited as part of the Human Heredity and Health (H3) in Africa Chronic Kidney Disease Case-Control Study in Nigeria. Tumor and adjacent normal tissue, and blood and saliva samples were collected for molecular and epigenetic assays.

RESULTS

Although recruitment is ongoing, a total of 416 patients have been recruited to date, with tumor and blood samples obtained from at least 310 patients. Data on age-matched (± 6 months) controls have also been obtained and harmonized. Lipid assays for 350 pathologically verified cases and 350 age-matched controls is underway, and pathologic characterization of tumors (including immunohistochemistry for subtyping) is ongoing. Data on DNA methylation for tumors and adjacent normal tissue are expected by the end of the study period.

CONCLUSION

The MEND study will provide a unique, high-quality source of data to evaluate the contribution of metabolic dysregulation such as obesity, diabetes, hypertension, and metabolic syndrome to the biology of breast cancer among Nigerian women and foster collaborative studies relevant for women of African descent globally.

Visceral obesity and cell cycle pathways serve as links in the association between bisphenol A exposure and breast cancer

It has been identified that bisphenol A (BPA) exposure causes developmental toxicity in breast cells. However, the exact molecular mechanisms underlying the association between exposure to BPA and breast cancer remain unclear. The aim of the present study was to investigate the BPA-regulated signaling pathways associated with the aggressiveness and the development of breast cancer. Microarray technology and functional gene set analyses were used to evaluate BPA and breast cancer-associated biomarkers and pathways in a discovery-driven manner. Using individual dataset analyses, it was indicated that two BPA-associated gene sets, the visceral obesity pathway, involved in visceral fat deposits and the metabolic syndrome, and the cell cycle pathway, involved in cyclins and cell cycle regulation, were significantly associated with a high grade of aggressiveness and the development of estrogen receptor (ER)-positive breast cancer (between P<0.05 and 0.0001). The pooled analysis indicated that the most significant pathway was G₁/S checkpoint regulation, and the cyclin and cell cycle regulation pathway for BPA-associated ER-positive cancer. Cancer cell signaling pathways were associated with healthy breast cells developing into breast cancer. The visceral obesity and the cell cycle pathways were indicated to link BPA exposure to breast cancer. The results of the present study demonstrate a significant association between breast cancer and BPA-regulated gene pathways.

A Non-canonical Function of BMAL1 Metabolically Limits Obesity-Promoted Triple-Negative Breast Cancer

The epidemiological association between disrupted circadian rhythms and metabolic diseases is implicated in increased risk of human breast cancer and poor therapeutic outcomes. To define a metabolic phenotype and the underlying molecular mechanism, we applied chronic insulin treatment (CIT) to an in vitro model of triple-negative breast cancer to directly address how BMAL1, a key circadian transcription factor, regulates cancer cell respiration and governs tumor progression. At the cellular level, BMAL1 suppresses the flexibility of mitochondrial substrate usage and the pyruvate-dependent mitochondrial respiration induced by CIT. We established an animal model of diet-induced obesity/hyperinsulinemia and observed that BMAL1 functions as a tumor suppressor in obese, but not lean, mice. Downregulation of BMAL1 is associated with higher risk of metastasis in human breast tumors. In summary, loss of BMAL1 in tumors confers advantages to cancer cells in both intrinsic mitochondrial metabolism and extrinsic inflammatory tumor microenvironment during pre-diabetic obesity/hyperinsulinemia.

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Circadian regulator BMAL1 rewires metabolism in a chronic insulin-treated TNBC model

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Pyruvate links BMAL1 to mitochondrial bioenergetics

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BMAL1 suppresses tumor proliferation and metastasis in hyperinsulinemic obese mice

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BMAL1 influences tumor microenvironment in high-fat-diet-fed mice

Metabolic Syndrome and the Risk of Breast Cancer and Subtypes by Race, Menopause and BMI

The objective of this study was to investigate the association of metabolic syndrome (MetS) with the risk of invasive breast cancer and molecular subtypes across race, menopause, and body mass index (BMI) groups. We examined the association of metabolic syndrome and its components with risk of invasive breast cancer among 94,555 female participants of the National Institute of Health-American Association of Retired Persons (NIH-AARP) Diet and Health Study, accounting for ductal carcinoma in situ as a competing risk. Cox proportional hazard regression with the Fine and Gray method was used to generate hazard ratios (HR) and 95% confidence intervals (CI) adjusting for baseline sociodemographic, behavioral, and clinical covariates. During a mean follow-up of 14 years, 5380 (5.7%) women developed breast cancer. Overall, MetS at baseline was associated with a 13% increased risk of breast cancer compared to women without MetS (HR: 1.13, 95% CI: 1.00, 1.27); similar estimates were obtained among postmenopausal women (HR: 1.14, 95% CI: 1.01, 1.29). MetS was associated with a slight but non-significantly increased risk of breast cancer among those with both normal weight and overweight/obesity, and those with estrogen receptor positive breast cancer subtype. In the NIH-AARP cohort, MetS was associated with an increased risk of breast cancer. Further studies are needed to definitively evaluate the association of MetS with triple negative breast cancer subtypes across all levels of BMI.

Cardiometabolic risk factors and survival after breast cancer in the Women's Health Initiative

BACKGROUND

Few studies have examined the relationship between cardiometabolic risk factors linked to metabolic syndrome and mortality among women with breast cancer.

METHODS

We used the Women's Health Initiative to evaluate the relationship between cardiometabolic risk factors, including waist circumference (WC), blood pressure, cholesterol level, and presence of type 2 diabetes, and their relation with death from breast cancer, cardiovascular disease (CVD), and other causes among 8641 women with local or regional stage invasive breast cancer. Cox proportional hazards models were used to estimate hazard ratios, and 95% confidence intervals, adjusted for important predictors of survival.

RESULTS

After a median of 11.3 years, there were 2181 total deaths, 619 (28.4%) of which were due to breast cancer. Most participants (55.7%) had at least 2 cardiometabolic risk factors, and 4.9% had 3 or 4. Having a larger number of risk factors was associated with higher risk of CVD and other-cause mortality (P trend < .001 for both), but not with breast cancer mortality (P trend = .86). Increased WC was associated with a higher risk of CVD (hazard ratio [HR], 1.28; 95% confidence interval [CI], 1.05-1.57) and other-cause mortality (HR, 1.32; 95% CI, 1.16-1.49) and only with a small and nonsignificant higher risk of breast cancer mortality (HR, 1.19; 95% CI, 0.93-1.52). The results did not differ in analyses stratified by race, hormone receptor status, or after an analysis of cases diagnosed within 5 years after baseline.

CONCLUSIONS

Among women with early stage breast cancer, cardiometabolic risk factors are significantly associated with cardiovascular and other-cause mortality, but not breast cancer mortality. Cancer 2018;124:1798-807. © 2018 American Cancer Society.

Metabolic dysregulation and cancer mortality in a national cohort of blacks and whites

Background

We examined the association between metabolic dysregulation and cancer mortality in a prospective cohort of Black and White adults.

Methods

A total of 25,038 Black and White adults were included in the analysis. Metabolic dysregulation was defined in two ways: 1) using the joint harmonized criteria for metabolic syndrome (MetS) and 2) based on factor analysis of 15 variables characterizing metabolic dysregulation. We estimated hazards ratios (HRs) and 95% confidence intervals (CIs) for the association of MetS and metabolic dysregulation with cancer mortality during follow-up using Cox proportional hazards models.

Results

About 46% of Black and 39% of White participants met the criteria for MetS. Overall, participants with MetS (HR: 1.22, 95% CI: 1.03–1.45) were at increased risk of cancer-related death. In race-stratified analysis, Black participants with MetS had significantly increased risk of cancer mortality compared with those without MetS (HR: 1.32, 95% CI: 1.01–1.72), increasing to more than a 2-fold risk of cancer mortality among those with five metabolic syndrome components (HR: 2.35, 95% CI: 1.01–5.51).

Conclusions

There are marked racial differences in the prevalence of metabolic dysregulation defined as MetS based on the harmonized criteria. The strong positive associations between MetS and cancer mortality suggests that efforts to improve cancer outcomes in general, and racial disparities in cancer outcomes specifically, may benefit from prevention and management of MetS and its components.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3807-2) contains supplementary material, which is available to authorized users.

Tumor-linked HER2 expression: association with obesity and lipid-related microenvironment

Obesity is associated with the risk of several health disorders including certain cancers. Among obesity-related cancers, postmenopausal breast carcinoma is a well-studied one. Apart from an increase in certain types of lipids in obesity, excess adipose tissue releases many hormone-like cytokines/adipokines, which are usually pro-inflammatory in nature. Leptin is one of such adipokines and significantly linked with the intracellular signaling pathways of other growth factors such as insulin-like growth factor-1 (IGF-1), vascular endothelial growth factor (VEGF), human epidermal growth factor receptor 2 (HER2). In general, HER2 is overexpressed in roughly 30% of breast carcinomas; its presence indicates aggressive tumor behavior. Conversely, HER2 has certain effects in normal conditions such as differentiation of preadipocytes, cardiovascular health and vitamin D metabolism. HER2 has no known endogenous ligand, but it may form dimers with other three members of the epidermal growth factor receptor (EGFR) family and can activate downstream signaling pathways. Furthermore, HER2 is intimately connected with several enzymes, e.g. fatty acid synthase (FASN), phosphatidylinositol 3-kinase (PI3K), AKT and mechanistic target of rapamycin (mTOR), all of which play significant regulatory roles in lipogenic pathways or lipid metabolism. In obesity-related carcinogenesis, characteristics like insulin resistance and elevated IGF-1 are commonly observed. Both IGF-1 and leptin can modulate EGFR and HER2 signaling pathways. Although clinical studies have shown mixed results, the behavior of HER2+ tumor cells including HER2 levels can be altered by several factors such as obesity, leptin and fatty acids. A precise knowledge is useful in new therapeutic approaches against HER+ tumors.

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.

Persistent organic pollutants and obesity: are they potential mechanisms for breast cancer promotion?

Dietary ingestion of persistent organic pollutants (POPs) is correlated with the development of obesity. Obesity alters metabolism, induces an inflammatory tissue microenvironment, and is also linked to diabetes and breast cancer risk/promotion of the disease. However, no direct evidence exists with regard to the correlation among all three of these factors (POPs, obesity, and breast cancer). Herein, we present results from current correlative studies indicating a causal link between POP exposure through diet and their bioaccumulation in adipose tissue that promotes the development of obesity and ultimately influences breast cancer development and/or progression. Furthermore, as endocrine disruptors, POPs could interfere with hormonally responsive tissue functions causing dysregulation of hormone signaling and cell function. This review highlights the critical need for advanced in vitro and in vivo model systems to elucidate the complex relationship among obesity, POPs, and breast cancer, and, more importantly, to delineate their multifaceted molecular, cellular, and biochemical mechanisms. Comprehensive in vitro and in vivo studies directly testing the observed correlations as well as detailing their molecular mechanisms are vital to cancer research and, ultimately, public health.

ZNF32 inhibits autophagy through the mTOR pathway and protects MCF-7 cells from stimulus-induced cell death

ZNF32 is a recently identified zinc finger protein and its functions remain largely unknown. Autophagy has been shown to affect cell proliferation and survival. Here, we innovatively show the effect of ZNF32 on cell autophagy and autophagy-associated cell death in breast carcinoma cells and also elucidate its underlying mechanisms. We examined the autophagic activity and LC3 II expression in human carcinoma cell lines with increased or decreased ZNF32 expression. Pharmacological inhibition (rapamycin) or activation (EGF) assays were used to investigate the function of the AKT/mTOR pathway during this process. H₂O₂- and diamide-induced MCF-7 cell death models were used to elucidate the role of ZNF32-associated autophagy in breast carcinoma cell death. Our results show that increasing ZNF32 expression in MCF-7 cells inhibits autophagy initiation by activating the AKT/mTOR pathway, and further reduced autophagy-associated cell death and maintained MCF-7 cell survival. Conversely, impairing ZNF32 expression by transfecting ZNF32 siRNA strongly promoted autophagy, further augmenting autophagy-associated cell death. Furthermore, correlations between ZNF32 and autophagy were observed in both MCF-7 xenograft tumors and in breast cancer patients. In conclusion, ZNF32 acts as an effective autophagy inhibitor to protect breast cancer cells from excessive stimulus-autophagy-induced cell death.