Diabetes and Breast Cancer Subtypes

Dietary-Based Diabetes Risk Score and breast cancer: a prospective evaluation in the SUN project

An association between type 2 diabetes (T2D) and breast cancer risk has been reported. This association can be potentially explained by alteration of the insulin/IGF system. Therefore, we aimed to prospectively investigate whether a previously reported Dietary-Based Diabetes Risk Score (DDS) inversely associated with T2D was also associated with breast cancer risk in the SUN ("Seguimiento Universidad de Navarra") cohort. We followed up 10,810 women (mean age = 35 years, SD = 11 years) for an average of 12.5 years during which 147 new cases of invasive breast cancer were diagnosed. A validated 136-item FFQ was administered at baseline and after 10 years of follow-up. The DDS (range: 11 to 55 points) positively weighted vegetables, fruit, whole cereals, nuts, coffee, low-fat dairy, fiber, PUFA; while it negatively weighted red meat, processed meats, and sugar-sweetened beverages. The DDS was categorized into tertiles. Self-reported medically diagnosed breast cancer cases were confirmed through medical records. We found a significant inverse association between the intermediate tertile of the DDS score and overall breast cancer risk (Hazard ratio, HRT2 vs. T1= 0.55; 95% CI: 0.36-0.82) and premenopausal breast cancer risk (HRT2= 0.26; 95% CI: 0.13-0.53), but not for the highest tertile. This association was stronger among women with a BMI < 25 kg/m2 (pinteraction: 0.029). In conclusion, moderate adherence to the DDS score was associated with a lower risk of breast cancer, especially among premenopausal women and women with a lower BMI. These findings underscore the importance of antidiabetic diet in reducing the risk of breast cancer.

Metformin Prevents Tumor Cell Growth and Invasion of Human Hormone Receptor-Positive Breast Cancer (HR+ BC) Cells via FOXA1 Inhibition

Women with type 2 diabetes (T2D) have a higher risk of being diagnosed with breast cancer and have worse survival than non-diabetic women if they do develop breast cancer. However, more research is needed to elucidate the biological underpinnings of these relationships. Here, we found that forkhead box A1 (FOXA1), a forkhead family transcription factor, and metformin (1,1-dimethylbiguanide hydrochloride), a medication used to treat T2D, may impact hormone-receptor-positive (HR+) breast cancer (BC) tumor cell growth and metastasis. Indeed, fourteen diabetes-associated genes are highly expressed in only three HR+ breast cancer cell lines but not the other subtypes utilizing a 53,805 gene database obtained from NCBI GEO. Among the diabetes-related genes, FOXA1, MTA3, PAK4, FGFR3, and KIF22 were highly expressed in HR+ breast cancer from 4032 breast cancer patient tissue samples using the Breast Cancer Gene Expression Omnibus. Notably, elevated FOXA1 expression correlated with poorer overall survival in patients with estrogen-receptor-positive/progesterone-receptor-positive (ER+/PR+) breast cancer. Furthermore, experiments demonstrated that loss of the FOXA1 gene inhibited tumor proliferation and invasion in vitro using MCF-7 and T47D HR+ breast cancer cell lines. Metformin, an anti-diabetic medication, significantly suppressed tumor cell growth in MCF-7 cells. Additionally, either metformin treatment or FOXA1 gene deletion enhanced tamoxifen-induced tumor growth inhibition in HR+ breast cancer cell lines within an ex vivo three-dimensional (3D) organoid model. Therefore, the diabetes-related medicine metformin and FOXA1 gene inhibition might be a new treatment for patients with HR+ breast cancer when combined with tamoxifen, an endocrine therapy.

Investigating the Association Between Type 2 Diabetes Mellitus and Pathological Responses Among Breast Cancer Patients Receiving Neoadjuvant Chemotherapy

INTRODUCTION

The relationship between type 2 diabetes mellitus (T2DM) and pathological responses after neoadjuvant chemotherapy (NACT) is controversial. In this study, we aim to determine the association of pathological responses in breast cancer women with T2DM after receiving NACT.

METHODS

Medical records of breast cancer women with T2DM who received NACT from January 2016 to January 2021 at the medical center in the Gujranwala Institute of Nuclear Medicine and Radiotherapy, Pakistan, were identified and retrieved retrospectively. Variables, including pathological responses, diabetes status, and other clinical data, were collected. Patients were grouped as diabetic and nondiabetic based on the doctor's diagnosis or the diabetic's medication history recorded upon the breast cancer diagnosis. Factors influencing the pathological complete response (pCR) were determined using multivariate logistic regression utilizing IBM SPSS Statistics (version 20).

RESULTS

A total of 1372 patient files who received NACT and breast cancer surgery from January 2016 to January 2021 were selected. Out of 1372 breast cancer women receiving NACT, 345 (25.1%) had pre-existing diabetes, while 1027 (74.85%) were without pre-existing diabetes. The most common molecular subtypes of breast cancer were luminal A and B. Two hundred fifty-eight patients (18.8%) had a pCR after receiving NACT. The pCR in diabetic patients was 3.9%, and in nondiabetes, 14.9%. Most women had a pathological partial response (pPR) after the NACT 672 (48.9%). The pPR in diabetic patients was 11.0%, and in nondiabetic patients, it was 38.0%. In nondiabetics, the odds of achieving pPR increase more than pathological no response after the NACT with odd ratio: 1.71 (95% confidence interval: 1.24-2.37). The probability of pCR in patients with luminal B was 1.67 times higher than that in patients with triple-negative breast cancer with odd ratio: 1.67, 95% confidence interval (1.00-2.79), P = 0.05.

CONCLUSIONS

The results of the study show that T2DM may have an adverse impact on pCR and pPR following NACT and surgery. Further investigation is needed to explore how changes in blood glucose levels over time impact pathological responses.

Estrogen Receptor Is Required for Metformin-Induced Apoptosis in Breast Cancer Cells Under Hyperglycemic Conditions

Backgrounds

About 25% to 30% of estrogen receptor (ER)-positive breast cancer patients develop resistance to endocrine therapy. Human epidermal growth factor receptor 2 (HER2) has been shown to cooperate with several growth factors that regulate cellular energy metabolism, including the insulin-like growth factor 1 receptor (IGF-1R).

Objective

As the first-line therapy for type 2 diabetes mellitus (T2DM) patients, metformin is widely known to inhibit the metabolic reprogramming of cancer cells. This study aims to investigate metformin's efficacy in inhibiting endocrine resistance related to genes regulating energy metabolism in both ER-positive and ER-negative breast cancer cell lines under hyperglycemic conditions.

Design and methods

MDA-MB-361 (ER-positive, HER2-positive) and SKBR3 (ER-negative, HER2-positive) cancer cell lines were used to represent ER status. Cell viability and cell survival rate were measured using the colorimetric assay of Cell Counting Kit-8. All mRNA levels were quantified using real-time quantitative polymerase chain reaction preceded by reverse transcription. A P value of <.05 was considered statistically significant.

Results

Unlike MDA-MB-361, SKBR3 were found to acquire resistance upon metformin treatment in hyperglycemic conditions. Moreover, the mRNA expression of IGF-1R and its downstream signaling, such as the mammalian target of rapamycin (mTOR), was not affected by metformin. Meanwhile, the mRNA expression level of ribosomal S6 kinase 1 (S6K1) was upregulated, whereas forkhead box O1 (FOXO1) was downregulated after metformin treatment in hyperglycemic conditions.

Conclusions

This preliminary study suggests that an alternative pathway of metformin resistance may exist in the absence of ERα. Therefore, relying solely on metformin may be inadequate to inhibit the aggressiveness of breast cancer cells.

YAP/TAZ axis was involved in the effects of metformin on breast cancer

Breast cancer is malignant tumours in women. A large amount of data analysis shows that Metformin has been shown to play a significance role in reducing the risk of breast cancer, but the mechanism remains unclear. The hippo signalling pathway can be involved in the formation, metastasis and recurrence of breast cancer. When YAP/TAZ is activated, cells can overcome contact inhibition and enter a state of uncontrolled proliferation. Therefore, YAP/TAZ is considered a potential therapeutic target for breast cancer. Eighty breast cancer patients, forty cases of triple-negative and forty cases of HER-2+, were included in this study. In vitro and in vivo experiments were used to confirm the YAP/TAZ axis was involved in the effects of metformin on breast cancer. EMT plays an important role in breast cancer, including chemoresistance and tumour metastasis. Our results confirmed that YAP could modulate the activity of EMT, which in turn altered tumour resistance. Therefore, MET can inhibit EMT by reducing the expression of YAP, and finally achieve the therapeutic effect of breast cancer. Our findings support metformin as a novel YAP inhibitor and potentially as a novel breast cancer drug.

Updates on Triple-Negative Breast Cancer in Type 2 Diabetes Mellitus Patients: From Risk Factors to Diagnosis, Biomarkers and Therapy

Triple-negative breast cancer (TNBC) is usually the most malignant and aggressive mammary epithelial tumor characterized by the lack of expression for estrogen receptors and progesterone receptors, and the absence of epidermal growth factor receptor (HER)2 amplification. Corresponding to 15-20% of all breast cancers and well-known by its poor clinical outcome, this negative receptor expression deprives TNBC from targeted therapy and makes its management therapeutically challenging. Type 2 diabetes mellitus (T2DM) is the most common ageing metabolic disorder due to insulin deficiency or resistance resulting in hyperglycemia, hyperinsulinemia, and hyperlipidemia. Due to metabolic and hormonal imbalances, there are many interplays between both chronic disorders leading to increased risk of breast cancer, especially TNBC, diagnosed in T2DM patients. The purpose of this review is to provide up-to-date information related to epidemiology and clinicopathological features, risk factors, diagnosis, biomarkers, and current therapy/clinical trials for TNBC patients with T2DM compared to non-diabetic counterparts. Thus, in-depth investigation of the diabetic complications on TNBC onset, development, and progression and the discovery of biomarkers would improve TNBC management through early diagnosis, tailoring therapy for a better outcome of T2DM patients diagnosed with TNBC.

Network pharmacology analysis reveals potential targets and mechanisms of proton pump inhibitors in breast cancer with diabetes

Breast cancer and diabetes are significant health challenges, and effective treatments for both diseases are lacking. Proton pump inhibitors (PPIs) have demonstrated anticancer and hypoglycemic effects, but their mechanisms of action are not yet fully understood. We used the GeneCards and PharmMapper databases to identify therapeutic targets for diabetes,  breast cancer and PPIs. We identified common targets and constructed a regulatory network of diseases and drugs using the STRING database and Cytoscape software. We also explored the binding between small molecule ligands and protein receptors using Discovery Studio software. We identified 33 shared targets for breast cancer, diabetes, and PPIs including lansoprazole, omeprazole, and pantoprazole, which play a critical role in fatty acid transport, insulin resistance, apoptosis, and cancer-related signaling pathways. Our findings demonstrated that PPIs had a strong affinity for AKT1 and MMP9. This study provides insights into the mechanisms of action of PPIs in breast cancer and diabetes and identifies AKT1 and MMP9 as critical targets for future drug development. Our findings highlight the potential of PPIs as a novel therapeutic approach for these challenging diseases.

Aspirin and Risk of Specific Breast Cancer Subtype in Women with Diabetes

Purpose: Low-dose aspirin was associated with a reduced risk of breast cancer in women with diabetes. However, whether the protective effect of aspirin varies as a function of the hormone receptor status of breast cancer remained an unanswered question. This study aims to explore the association between aspirin use and the risk of specific breast cancer subtypes in women with diabetes. Methods: Population-based retrospective cohort study of women with diabetes, using the Taiwan National Health Insurance reimbursement database (year 1998 to 2011). Patients diagnosed to have diabetes with new low-dose aspirin use (75-165 mg per day) for at least 28 days of prescription were identified as the study population, while patients without low-dose aspirin use were selected as controls. The main outcome measure was breast cancer by aspirin use and hormone receptor status. Results: We studied a total of 148,739 patients with diabetes. Their mean (standard deviation) age was 63.3 (12.8) years. During follow-up, a total of 849 breast cancers occurred, including 329 hormone receptor-positive and 529 hormone receptor-negative tumors. A total of 27,378 patients were taking aspirin. The reduction in risk with aspirin use was seen among those with hormone receptor-positive breast cancer (Hazard ratio [HR]: 0.73; 95% confidence interval [CI]: 0.59-0.91) but not for women with hormone receptor-negative breast cancer (HR: 0.88; 95% CI: 0.74-1.05). A cumulative dose of aspirin use of more than 8,600 mg was found to reduce the risk of hormone receptor-positive breast cancer by 31% (HR: 0.69; 95% CI: 0.50-0.97). A cumulative dose of aspirin use of more than 88,900 mg was found to reduce both the risk of hormone receptor-positive and negative breast cancer. Conclusion: These data add to the growing evidence that supports the use of low-dose aspirin as a potential chemopreventive agent for specific subtypes of breast cancer. Further studies are necessary to confirm these findings.

Association of diabetes and breast cancer characteristics at diagnosis

PURPOSE

This study aims to examine the association of diabetes and breast cancer characteristics at diagnosis in Aotearoa/New Zealand.

METHODS

Patients diagnosed with invasive breast cancer between 2005 and 2020 were identified from the National Breast Cancer Register. Logistic regression modeling was used to estimate the adjusted odds ratio (OR) of having stage III-IV cancer and the OR of having stage IV cancer for women with diabetes compared to those without diabetes. The adjusted OR of having screen-detected breast cancers for patients aged 45-69 years with diabetes compared to patients without diabetes was estimated.

RESULTS

26,968 women were diagnosed with breast cancer, with 3,137 (11.6%) patients having diabetes at the time of cancer diagnosis. The probability of co-occurrence of diabetes and breast cancer increased with time. Māori, Pacific and Asian women were more likely to have diabetes than European/Others. The probability of having diabetes also increased with age. For patients with diabetes, the probability of being diagnosed with stage III-IV cancer and stage IV cancer was higher than for patients without diabetes (OR 1.14, 95% CI 1.03-1.27; and 1.17, 95% CI 1.00-1.38). Women aged 45-69 years with diabetes were more likely to have screen-detected cancer than those without diabetes (OR 1.13, 95% CI 1.02-1.26).

CONCLUSIONS

The co-occurrence of diabetes and breast cancer is becoming more common. Overall there is a small but significant adverse impact of having advanced disease for women with diabetes that is found at the time of breast cancer diagnosis, and this may contribute to other inequities that occur in the treatment pathway that may impact on patient outcomes.

Factors associated with initiation and continuation of endocrine therapy in women with hormone receptor-positive breast cancer

Background

Despite benefits of endocrine therapy (ET) for patients with hormone-receptor (HR)-positive breast cancer, many patients do not initiate or discontinue ET against recommendations.

Methods

We identified variables associated with ET initiation and continuation, analyzing pooled data from two longitudinal studies at a National Cancer Institute comprehensive cancer center in St. Louis, Missouri. The sample included 533 women with newly diagnosed, non-metastatic, HR-positive breast cancer who completed interviews at enrollment and 6, 12, and 24 months after definitive surgical treatment. Logistic regression models estimated the adjusted odds ratio and 95% confidence interval (aOR [95% CI]) for each of self-reported ET initiation by the 12-month interview and continuation for ≥12 months by the 24-month interview in association with self-reported diabetes, elevated depressed mood, menopausal-symptom severity and obesity, adjusting for race, age, insurance status, chemotherapy, and radiation therapy.

Results

Overall, 81.4% (434/533) of patients initiated ET, and 86.5% (371/429) continued ET ≥12 months. Patients with diabetes had lower odds of initiating ET (0.50 [0.27-0.91]). Patients reporting greater menopausal-symptom severity had lower odds of continuing ET (0.72 [0.53-0.99]).

Conclusion

Efforts to increase ET initiation among patients with diabetes and better manage severe menopausal symptoms among ET users might promote ET continuation.

Clinical trial information

ClinicalTrials.gov: #NCT00929084.

The role and application of small extracellular vesicles in breast cancer

Breast cancer (BC) is the most common malignancy and the leading cause of cancer-related deaths in women worldwide. Currently, patients’ survival remains a challenge in BC due to the lack of effective targeted therapies and the difficult condition of patients with higher aggressiveness, metastasis and drug resistance. Small extracellular vesicles (sEVs), which are nanoscale vesicles with lipid bilayer envelopes released by various cell types in physiological and pathological conditions, play an important role in biological information transfer between cells. There is growing evidence that BC cell-derived sEVs may contribute to the establishment of a favorable microenvironment that supports cancer cells proliferation, invasion and metastasis. Moreover, sEVs provide a versatile platform not only for the diagnosis but also as a delivery vehicle for drugs. This review provides an overview of current new developments regarding the involvement of sEVs in BC pathogenesis, including tumor proliferation, invasion, metastasis, immune evasion, and drug resistance. In addition, sEVs act as messenger carriers carrying a variety of biomolecules such as proteins, nucleic acids, lipids and metabolites, making them as potential liquid biopsy biomarkers for BC diagnosis and prognosis. We also described the clinical applications of BC derived sEVs associated MiRs in the diagnosis and treatment of BC along with ongoing clinical trials which will assist future scientific endeavors in a more organized direction.

The burden and risks of emerging complications of diabetes mellitus

The traditional complications of diabetes mellitus are well known and continue to pose a considerable burden on millions of people living with diabetes mellitus. However, advances in the management of diabetes mellitus and, consequently, longer life expectancies, have resulted in the emergence of evidence of the existence of a different set of lesser-acknowledged diabetes mellitus complications. With declining mortality from vascular disease, which once accounted for more than 50% of deaths amongst people with diabetes mellitus, cancer and dementia now comprise the leading causes of death in people with diabetes mellitus in some countries or regions. Additionally, studies have demonstrated notable links between diabetes mellitus and a broad range of comorbidities, including cognitive decline, functional disability, affective disorders, obstructive sleep apnoea and liver disease, and have refined our understanding of the association between diabetes mellitus and infection. However, no published review currently synthesizes this evidence to provide an in-depth discussion of the burden and risks of these emerging complications. This Review summarizes information from systematic reviews and major cohort studies regarding emerging complications of type 1 and type 2 diabetes mellitus to identify and quantify associations, highlight gaps and discrepancies in the evidence, and consider implications for the future management of diabetes mellitus.

The AGEs/RAGE Transduction Signaling Prompts IL-8/CXCR1/2-Mediated Interaction between Cancer-Associated Fibroblasts (CAFs) and Breast Cancer Cells

Advanced glycation end products (AGEs) and the cognate receptor, named RAGE, are involved in metabolic disorders characterized by hyperglycemia, type 2 diabetes mellitus (T2DM) and obesity. Moreover, the AGEs/RAGE transduction pathway prompts a dysfunctional interaction between breast cancer cells and tumor stroma toward the acquisition of malignant features. However, the action of the AGEs/RAGE axis in the main players of the tumor microenvironment, named breast cancer-associated fibroblasts (CAFs), remains to be fully explored. In the present study, by chemokine array, we first assessed that interleukin-8 (IL-8) is the most up-regulated pro-inflammatory chemokine upon AGEs/RAGE activation in primary CAFs, obtained from breast tumors. Thereafter, we ascertained that the AGEs/RAGE signaling promotes a network cascade in CAFs, leading to the c-Fos-dependent regulation of IL-8. Next, using a conditioned medium from AGEs-exposed CAFs, we determined that IL-8/CXCR1/2 paracrine activation induces the acquisition of migratory and invasive features in MDA-MB-231 breast cancer cells. Altogether, our data provide new insights on the involvement of IL-8 in the AGEs/RAGE transduction pathway among the intricate connections linking breast cancer cells to the surrounding stroma. Hence, our findings may pave the way for further investigations to define the role of IL-8 as useful target for the better management of breast cancer patients exhibiting metabolic disorders.

Glucose deprivation reduces proliferation and motility, and enhances the anti-proliferative effects of paclitaxel and doxorubicin in breast cell lines in vitro

Background

Breast cancer chemotherapy with high dose alkylating agents is severely limited by their collateral toxicity to crucial normal tissues such as immune and gut cells. Taking advantage of the selective dependence of cancer cells on high glucose and combining glucose deprivation with these agents could produce therapeutic synergy.

Methods

In this study we examined the effect of glucose as well as its deprivation, and antagonism using the non-metabolized analogue 2-deoxy glucose, on the proliferation of several breast cancer cell lines MCF7, MDA-MB-231, YS1.2 and pII and one normal breast cell line, using the MTT assay. Motility was quantitatively assessed using the wound healing assay. Lactate, as the end product of anaerobic glucose metabolism, secreted into culture medium was measured by a biochemical assay. The effect of paclitaxel and doxorubicin on cell proliferation was tested in the absence and presence of low concentrations of glucose using MTT assay.

Results

In all cell lines, glucose supplementation enhanced while glucose deprivation reduced both their proliferation and motility. Lactate added to the medium could substitute for glucose. The inhibitory effects of paclitaxel and doxorubicin were significantly enhanced when glucose concentration was decreased in the culture medium, requiring 1000-fold lesser concentration to achieve a similar degree of inhibition to that seen in glucose-containing medium.

Conclusion

Our data show that a synergy was obtained by combining paclitaxel and doxorubicin with glucose reduction to inhibit cancer cell growth, which in vivo, might be achieved by applying a carbohydrate-restricted diet during the limited phase of application of chemotherapy; this could permit a dose reduction of the cytotoxic agents, resulting in greater tolerance and lesser side effects.

Association of Obesity and Diabetes With the Incidence of Breast Cancer in Louisiana

INTRODUCTION

Breast cancer is a heterogeneous disease, consisting of multiple molecular subtypes. Obesity has been associated with an increased risk for postmenopausal breast cancer, but few studies have examined breast cancer subtypes separately. Obesity is often complicated by type 2 diabetes, but the possible association of diabetes with specific breast cancer subtypes remains poorly understood.

METHODS

In this retrospective case-control study, Louisiana Tumor Registry records of primary invasive breast cancer diagnosed in 2010-2015 were linked to electronic health records in the Louisiana Public Health Institute's Research Action for Health Network. Controls were selected from Research Action for Health Network and matched to cases by age and race. Conditional logistic regression was used to identify metabolic risk factors. Data analysis was conducted in 2020‒2021.

RESULTS

There was a significant association between diabetes and breast cancer for Luminal A, Triple-Negative Breast Cancer, and human epidermal growth factor 2‒positive subtypes. In multiple logistic regression, including both obesity status and diabetes as independent risk factors, Luminal A breast cancer was also associated with overweight status. Diabetes was associated with increased risk for Luminal A and Triple-Negative Breast Cancer in subgroup analyses, including women aged ≥50 years, Black women, and White women.

CONCLUSIONS

Although research has identified obesity and diabetes as risk factors for breast cancer, these results underscore that comorbid risk is complex and may differ by molecular subtype. There was a significant association between diabetes and the incidence of Luminal A, Triple-Negative Breast Cancer, and human epidermal growth factor 2‒positive breast cancer in Louisiana.

The regulation of insulin receptor/insulin-like growth factor 1 receptor ratio, an important factor for breast cancer prognosis, by TRIP-Br1

Much higher risk of cancer has been found in diabetes patients. Insulin receptor (IR) and insulin-like growth factor 1 receptor (IGF1R) have been extensively studied in both breast cancer and diabetes therapies. Interestingly, a recent study proposed that IR/IGF1R ratio is an important factor for breast cancer prognosis. Women with higher IR/IGF1R ratio showed poor breast cancer prognosis as well as hyperinsulinemia. Here, we propose a novel mechanism that oncogenic protein TRIP-Br1 renders breast cancer cells and insulin deficient mice to have higher IR/IGF1R ratio by positively and negatively regulating IR and IGF1R expression at the protein level, respectively. TRIP-Br1 repressed IR degradation by suppressing its ubiquitination. Meanwhile, TRIP-Br1 directly interacts with both IGF1R and NEDD4-1 E3 ubiquitin ligase, in which TRIP-Br1/NEDD4-1 degrades IGF1R via ubiquitin/proteasome system. TRIP-Br1-mediated higher IR/IGF1R ratio enhanced the proliferation and survival of breast cancer cells. In conclusion, current study may provide an important information in the regulatory mechanism of how breast cancer cells have acquired higher IR/IGF1R ratio.

Cancer-cell-secreted extracellular vesicles suppress insulin secretion through miR-122 to impair systemic glucose homeostasis and contribute to tumour growth

Epidemiological studies demonstrate an association between breast cancer (BC) and systemic dysregulation of glucose metabolism. However, how BC influences glucose homeostasis remains unknown. We show that BC-derived extracellular vesicles (EVs) suppress pancreatic insulin secretion to impair glucose homeostasis. EV-encapsulated miR-122 targets PKM in β-cells to suppress glycolysis and ATP-dependent insulin exocytosis. Mice receiving high-miR-122 EVs or bearing BC tumours exhibit suppressed insulin secretion, enhanced endogenous glucose production, impaired glucose tolerance and fasting hyperglycaemia. These effects contribute to tumour growth and are abolished by inhibiting EV secretion or miR-122, restoring PKM in β-cells or supplementing insulin. Compared with non-cancer controls, patients with BC have higher levels of circulating EV-encapsulated miR-122 and fasting glucose concentrations but lower fasting insulin; miR-122 levels are positively associated with glucose and negatively associated with insulin. Therefore, EV-mediated impairment of whole-body glycaemic control may contribute to tumour progression and incidence of type 2 diabetes in some patients with BC.

Pathological Significance of GLUT-1 Expression in Breast Cancer Cells in Diabetic and Obese Patients: The French Guiana Study

Simple Summary

This study describes the clinical, histological, and molecular features of breast cancer in French Guiana, and characterizes the expression of the tumor metabolic marker GLUT-1 in breast cancers cells in diabetic and obese patients compared to a control group. This study reveals an overall overexpression of GLUT-1 in 60% of invasive breast carcinomas and in all medullary pattern and carcinoma in situ lesions. Our results highlight the potential role of GLUT-1 as a tumor metabolic prognostic marker and also as an interesting target therapy, independently of patient metabolic disorder.

Abstract

The prevalence of obesity and type 2 diabetes is higher in French Guiana compared to mainland France. These metabolic disorders are associated with an increased risk of cancer. One of the factors involved is hyperinsulinemia that promotes the action of glucose transporter 1 (GLUT-1). The objective of this study is to characterize the expression of GLUT-1 in breast cancers cells in diabetic and obese patients compared to those who are not and to describe the clinical and histological prognostic factors of breast cancer in this population. We conducted a monocentric study including patients with breast cancer diagnosed between 2014 and 2020. Patients were classified into three groups: diabetes, obesity, and control group. The GLUT-1 expression was assessed by immunohistochemistry. In total, 199 patients were included in this study. The median age was 53.5 years, and the median tumor size was 2.8 cm. Luminal A was the most frequent molecular type (58.1%), followed by the triple-negative type (19.9%). The breast cancer in our population was characterized by a younger age at diagnosis, more aggressive molecular types, and larger tumor size. Thus, we suggest the advancement of the age of breast cancer screening in this territory. A total of 144 patients (31 diabetes, 22 obese, and 91 control group) were included for the study of GLUT-1 expression. Overexpression of GLUT-1 was observed in 60.4% of cases and in all carcinoma in situ lesions. GLUT-1 overexpression was associated with more aggressive cancers. This overexpression is correlated with high histological grade, high proliferation index, and aggressive molecular types. Our study found no difference in GLUT-1 expression between the diabetic or obese patients and the control group. These results highlight the potential role of GLUT-1 as a tumor metabolic prognostic marker and also as an interesting target therapy, independently of patient metabolic disorder.

Type 2 Diabetes and all-cause mortality among Spanish women with breast cancer

PURPOSE

To explore the effect of type 2 diabetes mellitus (T2DM) on the risk of death among women with breast cancer (BC).

METHODS

A survival analysis was conducted among a cohort of women diagnosed with BC between 2006 and 2012 in Spain (n = 4,493). Biopsy or surgery confirmed BC cases were identified through the state population-based cancer registry with information on patients' characteristics and vital status. Physician-diagnosed T2DM was confirmed based on primary health care clinical history. Cox regression analyses were used to estimate adjusted hazard ratios (aHR) and 95% confidence intervals (CI) for all-cause death. Analyses were adjusted for age, hospital size, several clinical characteristics (including BC stage and histology, among others) and treatment modalities.

RESULTS

Among the 4,493 BC women, 388 (8.6%) had coexisting T2DM. Overall, 1,299 (28.9%) BC women died during the completion of the follow-up and 785 (17.5%) did so during the first five years after BC diagnosis, resulting in a five-year survival rate of 82.5%. The death rate was higher in women with T2DM (43.8% died during whole period and 26.0% during the first five years) when compared with women without T2DM (27.5% and 16.7%, respectively). Accordingly, all-cause mortality was higher in women with T2DM (aHR: 1.22; 95% CI 1.03-1.44), especially if T2DM was diagnosed before BC (aHR:1.24; 95% CI 1.03-1.50) and in women with BC diagnosed before 50 years (aHR: 2.38; 95% CI 1.04-5.48).

CONCLUSIONS

T2DM was associated with higher all-cause mortality among Spanish women with BC, particularly when the T2DM diagnosis was prior to the BC.

Type 2 Diabetes Mellitus and Clinicopathological Tumor Characteristics in Women Diagnosed with Breast Cancer: A Systematic Review and Meta-Analysis

Poor prognosis caused by type 2 diabetes mellitus (T2DM) in women with breast cancer is conferred, while the association between T2DM and breast tumor aggressiveness is still a matter of debate. This study aimed to clarify the differences in breast cancer characteristics, including stage, size, lymph node status, grade, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor (Her2), between patients with and without pre-existing T2DM. PubMed, Embase, and Web of Science were searched for studies from 1 January 2010 to 2 July 2021. Adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were pooled by using a random effects model. T2DM was significantly associated with tumor stages III/IV versus cancers in situ and stages I/II (pooled ORs (pOR), 95% CI: 1.19; 1.04-1.36, p = 0.012), tumor size >20 versus ≤20 mm (pOR, 95% CI: 1.18; 1.04-1.35, p = 0.013), and lymph node invasion versus no involvement (pOR, 95% CI: 1.26; 1.05-1.51, p = 0.013). These findings suggest that women with T2DM are at a higher risk of late-stage tumors, large tumor sizes, and invasive lymph nodes at breast cancer diagnosis.

A molecular link between diabetes and breast cancer: Therapeutic potential of repurposing incretin-based therapies for breast cancer

Female breast cancer recently surpassed lung cancer and became the most commonly diagnosed cancer worldwide. As per the recent data from WHO, breast cancer accounts for one out of every 8 cancer cases diagnosed among an estimated 2.3 million new cancer cases. Breast cancer is the most prevailing cancer type among women causing the highest number of cancer-related mortality. It has been estimated that in 2020, 68,5000 women died due to this disease. Breast cancers have varying degrees of molecular heterogeneity; therefore, they are divided into various molecular clinical sub types. Recent reports suggest that type 2 diabetes (one of the common chronic diseases worldwide) is linked to the higher incidence, accelerated progression, and aggressiveness of different cancers; especially breast cancer. Breast cancer is hormone-dependent in nature and has a cross-talk with metabolism. A number of antidiabetic therapies are known to exert beneficial effects on various types of cancers, including breast cancer. However, only a few reports are available on the role of incretin-based antidiabetic therapies in cancer as a whole and in breast cancer in particular. The present review sheds light on the potential of incretin based therapies on breast cancer and explores the plausible underlying mechanisms. Additionally, we have also discussed the sub types of breast cancer as well as the intricate relationship between diabetes and breast cancer.

Obesity, Type 2 Diabetes, and Cancer Risk

Obesity and type 2 diabetes have both been associated with increased cancer risk and are becoming increasingly prevalent. Metabolic abnormalities such as insulin resistance and dyslipidemia are associated with both obesity and type 2 diabetes and have been implicated in the obesity-cancer relationship. Multiple mechanisms have been proposed to link obesity and diabetes with cancer progression, including an increase in insulin/IGF-1 signaling, lipid and glucose uptake and metabolism, alterations in the profile of cytokines, chemokines, and adipokines, as well as changes in the adipose tissue directly adjacent to the cancer sites. This review aims to summarize and provide an update on the epidemiological and mechanistic evidence linking obesity and type 2 diabetes with cancer, focusing on the roles of insulin, lipids, and adipose tissue.

Cancer health disparities in racial/ethnic minorities in the United States

There are well-established disparities in cancer incidence and outcomes by race/ethnicity that result from the interplay between structural, socioeconomic, socio-environmental, behavioural and biological factors. However, large research studies designed to investigate factors contributing to cancer aetiology and progression have mainly focused on populations of European origin. The limitations in clinicopathological and genetic data, as well as the reduced availability of biospecimens from diverse populations, contribute to the knowledge gap and have the potential to widen cancer health disparities. In this review, we summarise reported disparities and associated factors in the United States of America (USA) for the most common cancers (breast, prostate, lung and colon), and for a subset of other cancers that highlight the complexity of disparities (gastric, liver, pancreas and leukaemia). We focus on populations commonly identified and referred to as racial/ethnic minorities in the USA-African Americans/Blacks, American Indians and Alaska Natives, Asians, Native Hawaiians/other Pacific Islanders and Hispanics/Latinos. We conclude that even though substantial progress has been made in understanding the factors underlying cancer health disparities, marked inequities persist. Additional efforts are needed to include participants from diverse populations in the research of cancer aetiology, biology and treatment. Furthermore, to eliminate cancer health disparities, it will be necessary to facilitate access to, and utilisation of, health services to all individuals, and to address structural inequities, including racism, that disproportionally affect racial/ethnic minorities in the USA.

Cross Talk between COVID-19 and Breast Cancer

Cancer patients are more susceptible to COVID-19; however, the prevalence of COVID-19 in different types of cancer is still inconsistent and inconclusive. Here, we delineate the intricate relationship between breast cancer and COVID-19. Breast cancer and COVID-19 share the involvement of common comorbidities, hormonal signalling pathways, gender differences, rennin- angiotensin system (RAS), angiotensin-converting enzyme-2 (ACE-2), transmembrane protease serine 2 (TMPRSS2) and dipeptidyl peptidase-IV (DPP-IV). We also shed light on the possible effects of therapeutic modalities of COVID-19 on breast cancer outcomes. Briefly, we conclude that breast cancer patients are more susceptible to COVID-19 in comparison with their normal counterparts. Women are more resistant to the occurrence and severity of COVID-19. Increased expressions of ACE2 and TMPRSS2 are correlated with occurrence and severity of COVID-19, but higher expression of ACE2 and lower expression of TMPRSS2 are prognostic markers for overall disease free survival in breast cancer. The ACE2 inhibitors and ibuprofen therapies for COVID-19 treatment may aggravate the clinical condition of breast cancer patients through chemo-resistance and metastasis. Most of the available therapeutic modalities for COVID-19 were also found to exert positive effects on breast cancer outcomes. Besides drugs in clinical trend, TMPRSS2 inhibitors, estrogen supplementation, androgen deprivation and DPP-IV inhibitors may also be used to treat breast cancer patients infected with SARS-CoV-2. However, drug-drug interactions suggest that some of the drugs used for the treatment of COVID-19 may modulate the drug metabolism of anticancer therapies which may lead to adverse drug reaction events.

The midlife transition and the risk of cardiovascular disease and cancer Part I: magnitude and mechanisms

Heart disease and cancer are the leading causes of death in the United States. In women, the clinical appearance of both entities-coronary heart disease and cancer (breast, endometrium, and ovary)-escalate during the decades of the midlife transition encompassing the menopause. In addition to the impact of aging, during the interval between the age of 40 and 65 years, the pathophysiologic components of metabolic syndrome also emerge and accelerate. These include visceral adiposity (measured as waist circumference), hypertension, diabetes, and dyslipidemia. Osteoporosis, osteoarthritis, sarcopenia, depression, and even cognitive decline and dementia appear, and most, if not all, are considered functionally related. Two clinical reports confirm the interaction linking the emergence of disease: endometrial cancer and metabolic syndrome. One describes the discovery of unsuspected endometrial cancer in a large series of elective hysterectomies performed in aged and metabolically susceptible populations. The other is from the Women's Health Initiative Observational Study, which found a positive interaction between endometrial cancer and metabolic syndrome regardless of the presence or absence of visceral adiposity. Both provide additional statistical support for the long-suspected causal interaction among the parallel but variable occurrence of these common entities-visceral obesity, heart disease, diabetes, cancer, and the prevalence of metabolic syndrome. Therefore, 2 critical clinical questions require analysis and answers: 1: Why do chronic diseases of adulthood-metabolic, cardiovascular, endocrine-and, in women, cancers of the breast and endometrium (tissues and tumors replete with estrogen receptors) emerge and their incidence trajectories accelerate during the postmenopausal period when little or no endogenous estradiol is available, and yet the therapeutic application of estrogen stimulates their appearance? 2: To what extent should identification of these etiologic driving forces require modification of the gynecologist's responsibilities in the care of our patients in the postreproductive decades of the female life cycle? Part l of this 2-part set of "expert reviews" defines the dimensions, gravity, and interactive synergy of each clinical challenge gynecologists face while caring for their midlife (primarily postmenopausal) patients. It describes the clinically identifiable, potentially treatable, pathogenic mechanisms driving these threats to quality of life and longevity. Part 2 (accepted, American Journal of Obstetrics & Gynecology) identifies 7 objectives of successful clinical care, offers "triage" prioritization targets, and provides feasible opportunities for insertion of primary preventive care initiatives. To implement these goals, a reprogrammed, repurposed office visit is described.

Association between prior use of anti-diabetic medication and breast cancer stage at diagnosis

BACKGROUND

Knowledge regarding antidiabetic medication (ADM) use prior to breast cancer (BC) diagnosis remains limited. The objectives were to (1) evaluate if the prior use of ADM was associated with BC stage at diagnosis and (2) identify and compare patient characteristics among BC patients using different ADMs.

RESEARCH DESIGN AND METHODS

Newly diagnosed female BC patients exposed to any medication during one year prior to cancer diagnosis were identified in 2008-2013 Linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database. Stage at diagnosis, categorized as early and advanced, was the primary outcome. Chi-square tests were used to compare characteristics and logistic regression models were applied to examine the effect while controlling for patient's characteristics.

RESULTS

A total of 1,719 female BC patients used ADM while 6,084 patients were non-ADM users. Although a higher proportion of ADM users (20.36%) were diagnosed with advanced stage compared to the non-ADM users (14.46%), the difference was not statistically significant after adjusting for the patients' characteristics. Besides, insulin users were more likely to be diagnosed with advanced stage (adjusted odds ratio 1.69; 95% CI 1.15, 2.48) compared to metformin users.

CONCLUSIONS

The association between ADM use and BC diagnostic characteristics varied based on different treatments.

Breast cancer risk factors and their effects on survival: a Mendelian randomisation study

BACKGROUND

Observational studies have investigated the association of risk factors with breast cancer prognosis. However, the results have been conflicting and it has been challenging to establish causality due to potential residual confounding. Using a Mendelian randomisation (MR) approach, we aimed to examine the potential causal association between breast cancer-specific survival and nine established risk factors for breast cancer: alcohol consumption, body mass index, height, physical activity, mammographic density, age at menarche or menopause, smoking, and type 2 diabetes mellitus (T2DM).

METHODS

We conducted a two-sample MR analysis on data from the Breast Cancer Association Consortium (BCAC) and risk factor summary estimates from the GWAS Catalog. The BCAC data included 86,627 female patients of European ancestry with 7054 breast cancer-specific deaths during 15 years of follow-up. Of these, 59,378 were estrogen receptor (ER)-positive and 13,692 were ER-negative breast cancer patients. For the significant association, we used sensitivity analyses and a multivariable MR model. All risk factor associations were also examined in a model adjusted by other prognostic factors.

RESULTS

Increased genetic liability to T2DM was significantly associated with worse breast cancer-specific survival (hazard ratio [HR] = 1.10, 95% confidence interval [CI] = 1.03-1.17, P value [P] = 0.003). There were no significant associations after multiple testing correction for any of the risk factors in the ER-status subtypes. For the reported significant association with T2DM, the sensitivity analyses did not show evidence for violation of the MR assumptions nor that the association was due to increased BMI. The association remained significant when adjusting by other prognostic factors.

CONCLUSIONS

This extensive MR analysis suggests that T2DM may be causally associated with worse breast cancer-specific survival and therefore that treating T2DM may improve prognosis.

Type 2 Diabetes Mellitus Induced Paracrine Effects on Breast Cancer Metastasis Through Extracellular Vesicles Derived from Human Mesenchymal Stem Cells

Cancer metastasis is the leading cause of mortality among breast cancer patients. Type 2 diabetes mellitus (T2DM) has been suggested as a risk factor of breast cancer; however, whether or not T2DM is associated with breast tumor metastasis remains unclear. In this study, we examined the involvement of T2DM with breast cancer metastasis by a combined approach of a meta-analysis and experimental research. The results of a systematic review and meta-analysis suggested that diabetes significantly increases the risk of lymph node metastasis by 1.10-fold (P < 0.01). Consistently, our data from experimental research showed that T2DM induced paracrine effects of mesenchymal stem cells (MSCs), a key contributor to cancer progression, to stimulate metastasis of breast cancer cells (BCCs) by two independent mechanisms. First, T2DM induced the excess secretion of interleukin 6 (IL6) from MSCs, which activated the JAK/STAT3 pathway in BCCs, thus promoting the metastasis of BCCs. Second, beside the EGR-1-/IL6-dependent mechanism, T2DM altered the functions of MSC-derived extracellular vesicles (EVs), which are highly associated with the metastasis of BCCs. Our present study showed that T2DM is a risk factor for breast cancer metastasis, and MSC-derived EVs might be useful for developing a novel anti-breast cancer therapy strategy.

Diabetes as a Risk Factor for Breast Cancer

Diabetes is one of the most important chronic conditions worldwide, and breast cancer is the most prevalent cancer in women worldwide. Several types of research have been conducted to ascertain the link between diabetes and its potential for increasing the risk of breast cancer. This research aims to determine the relationship between diabetes and breast cancer; patients with diabetes have a higher risk than the general population of developing cancer, and diabetes patients have a higher incidence and mortality of breast cancer. This research also reviewed the relationship between cytokines, the mitogenic effect of insulin-like growth factors, and breast cells. The review includes searching the PubMed database using the keywords "diabetes," "breast cancer," "risk factor," and "premenopausal." The search returned 53 articles used for review of this article.

Type 2 diabetes, breast cancer specific and overall mortality: Associations by metformin use and modification by race, body mass, and estrogen receptor status

INTRODUCTION

While type 2 diabetes (T2D) has been associated with increased all-cause mortality among women diagnosed with breast cancer (BC), the association between T2D and breast cancer-specific (BCS) mortality is unresolved. The goal of this study was to examine the association between T2D and BCS mortality and examine the influence of metformin treatment on mortality rates.

METHODS

A retrospective cohort study was conducted between 2002 and 2008 at Emory University Hospitals among non-Hispanic black and white women who had confirmed diagnosis of stage I-III BC and known diabetes status (T2D: n = 73; non-T2D: n = 514). Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

Compared to non-T2D patients, T2D women had almost a 2-fold increase in BCS mortality after adjusting for covariates (HR = 2.01; 95%CI = 1.02-3.98). Though attenuated, the increased hazard of death was also observed for all-cause mortality (HR = 1.74; 95%CI = 1.06-2.87). T2D patients who were not on metformin had substantially higher hazard of BCS mortality compared to non-diabetic patients (HR = 4.54; 95%CI = 1.98-10.44), whereas the association among T2D patients treated with metformin was weak (HR = 1.20; 95%CI = 0.36-3.97) and included the null.

CONCLUSIONS

Among women with BC, T2D is associated with increased BCS mortality. Metformin treatment for T2D during the initial diagnosis of BC may improve outcomes.

Using Phosphatidylinositol Phosphorylation as Markers for Hyperglycemic Related Breast Cancer

Studies have suggested that type 2 diabetes (T2D) is associated with a higher incidence of breast cancer and related mortality rates. T2D postmenopausal women have an ~20% increased chance of developing breast cancer, and women with T2D and breast cancer have a 50% increase in mortality compared to breast cancer patients without diabetes. This correlation has been attributed to the general activation of insulin receptor signaling, glucose metabolism, phosphatidylinositol (PI) kinases, and growth pathways. Furthermore, the presence of breast cancer specific PI kinase and/or phosphatase mutations enhance metastatic breast cancer phenotypes. We hypothesized that each of the breast cancer subtypes may have characteristic PI phosphorylation profiles that are changed in T2D conditions. Therefore, we sought to characterize the PI phosphorylation when equilibrated in normal glycemic versus hyperglycemic serum conditions. Our results suggest that hyperglycemia leads to: 1) A reduction in PI3P and PIP3, with increased PI4P that is later converted to PI(3,4)P2 at the cell surface in hormone receptor positive breast cancer; 2) a reduction in PI3P and PI4P with increased PIP3 surface expression in human epidermal growth factor receptor 2-positive (HER2+) breast cancer; and 3) an increase in di- and tri-phosphorylated PIs due to turnover of PI3P in triple negative breast cancer. This study begins to describe some of the crucial changes in PIs that play a role in T2D related breast cancer incidence and metastasis.

<p>Glycosylated Hemoglobin A1c Is Associated with Anthropometric Measurements and Tumor Characteristics in Breast Cancer Patients</p>

Purpose

To investigate the association between glycosylated hemoglobin A1c (HbA1c) with anthropometric measurements and clinicopathologic characteristics of breast cancer patients. Such data are lacking in Arabian countries.

Patients and Methods

A cross-sectional study was conducted at the Outpatient Oncology Unit at King Hussein Medical Center at the Royal Medical Services (RMS) and 223 breast cancer patients were included. Blood levels of HbA1c were measured and patients were classified into normal/non-diabetic (HbA1c <5.7%), prediabetic (HbA1c 5.7–6.4%), and diabetic (HbA1c ≥6.5%).

Results

The average age of patients was 49.9±10.3 years. Most patients had waist circumference equal to or more than 80 cm (91.9%) and more than half (55.2%) had waist-hip ratio equal to or more than 0.85. Mean body mass index (BMI) was 29.9±5.7 kg/m². The mean level of HbA1c was 6.2±1.4% (range 4.7% to 12.6%). HbA1c levels revealed that most patients in this study classified as prediabetics (44.4%). There was a significant positive correlation between HbA1c levels and each of patient's age (r=0.267, p<0.001), waist circumference (r=0.180, p=0.008), and waist-hip ratio (r=0.278, p<0.001). Compared with premenopausal breast cancer patients, postmenopausal patients had significantly higher HbA1c blood levels (t=–3.542, p=0.003). HbA1c was significantly associated with stage (p=0.044) and grade (p=0.016) of carcinoma in premenopausal breast cancer patients. Among postmenopausal cases, HbA1c was significantly associated with molecular subtype of the disease (p=0.039).

Conclusion

The majority of Jordanian breast cancer patients in this study are prediabetic, obese, and had visceral obesity. HbA1c levels are increased among older patients and those who have greater waist circumference and waist-hip ratio. HbA1c is associated with advanced stage and grade of breast carcinoma in premenopausal patients and with molecular subtype in postmenopausal cases. These findings urge the need to screen breast cancer patients for glycemic status upon disease presentation and to further consider treatments to control hyperglycemia in order to reduce the impact of metabolic derangements on disease prognosis and outcomes.

Increasing risk of diabetes mellitus in postmenopausal women with newly diagnosed primary breast cancer

AIMS/INTRODUCTION

We sought to determine if postmenopausal women who develop breast cancer are at increased risk of developing diabetes mellitus.

MATERIALS AND METHODS

The Taiwan National Health Insurance Research Database was searched from 2001 to 2015 for women aged ≥55 years (postmenopausal) with a diagnosis of primary breast cancer. Participants were age-matched with women without breast cancer in a 1:5 ratio. Cox proportional hazards analyses were used to examine associations between breast cancer, risk factors and the development of diabetes mellitus.

RESULTS

A total of 4,607 women with primary breast cancer and 23,035 age-matched controls without breast cancer were included (mean age 58.6 ± 9.1 years). Adjusting for age, income, urbanization, Charlson Comorbidity Index and medical conditions, the risk of diabetes mellitus for participants with breast cancer at 1, 5, 10 and 15 years was 1.70-, 1.34-, 1.27- and 1.24-fold higher, respectively, than for participants without breast cancer (adjusted hazard ratio [aHR] 1.70, 95% confidence interval [CI] 1.40-2.05; aHR 1.34, 95% CI 1.17-1.54; aHR 1.27, 95% CI 1.13-1.44; aHR 1.24, 95% CI 1.11-1.40). The risk of diabetes mellitus at 1 year for breast cancer patients receiving hormone therapy was 1.22-fold higher than in those not receiving hormone therapy (aHR 1.22, 95% CI 0.86-1.74), but without statistical significance.

CONCLUSIONS

Postmenopausal women with breast cancer are at increased risk of developing diabetes mellitus, independent of receiving hormone therapy, and should be closely monitored to establish an early diagnosis and therapeutic intervention for improving related outcomes.

Endocrine Therapy-related Endocrinopathies-Biology, Prevalence and Implications for the Management of Breast Cancer

Nearly 270,000 new breast cancer cases are predicted to be diagnosed in the USA in 2019 with more than 70% being estrogen receptor positive and treated using endocrine therapy. The suppression of estrogen biosynthesis or action via the use of ovarian suppression, aromatase inhibitors and selective estrogen receptor modulators/degraders, respectively, is effective in approximately 70% of women. The systemic inhibition of estrogen during breast cancer treatment is also associated with side effects due to the important endocrine functions of this steroid hormone, including its role in the maintenance of energy homeostasis and bone health. The current work will present perspectives of the impact of endocrine therapy from the point of view of breast medical oncology, endocrinology, and basic science.

Diabetes and its Potential Impact on Head and Neck Oncogenesis

In recent years, the incidence of diabetes mellitus and cancer has increased sharply; indeed, these have become the two most important diseases threatening health and survival. Head and neck (HN) tumors are the sixth most common malignancies in humans. Numerous studies have shown that there are many common risk factors for diabetes mellitus and HN squamous cell carcinoma, including advanced age, poor diet and lifestyle, and environmental factors. However, the mechanism linking the two diseases has not been identified. A number of studies have shown that diabetes affects the development, metastasis, and prognosis of HN cancer, potentially through the associated hyperglycemia, hyperinsulinemia and insulin resistance, or chronic inflammation. More recent studies show that metformin, the first-line drug for the treatment of type 2 diabetes, can significantly reduce the risk of HN tumor development and reduce mortality in diabetic patients. Here, we review recent progress in the study of the relationship between diabetes mellitus and HN carcinogenesis, and its potential mechanisms, in order to provide a scientific basis for the early diagnosis and effective treatment of these diseases.

Relationship between Diabetes and Diabetes Medications and Risk of Different Molecular Subtypes of Breast Cancer

BACKGROUND

Type II diabetes and certain diabetes treatments have been observed to impact breast cancer risk. However, their associations with different breast cancer molecular subtype defined by estrogen receptor (ER)/progesterone receptor (PR)/HER2 status are unclear.

METHODS

We conducted a retrospective multi-center population-based case-case study consisting of 4,557 breast cancer cases to evaluate the impact of type II diabetes and diabetes medications on the risk of different breast cancer molecular subtypes [ER⁺/HER2^-, ER⁺/HER2⁺, triple negative (ER^-/PR^-/HER2^-), and HER2 overexpressing (H2E, ER^-/PR^-/HER2⁺)]. Using ER⁺/HER2^- cases as the reference group, we estimated ORs and corresponding 95% confidence intervals (CI) for each subtype using polytomous logistic regression.

RESULTS

Compared with those without a diabetes history, women with type II diabetes had a 38% (95% CI, 1.01-1.89) increased odds of triple-negative breast cancer (TNBC). Current and longer term recent metformin use (13-24 months of treatment within the 24-month period prior to breast cancer diagnosis) was associated with elevated odds of TNBC (OR = 1.54; 95% CI, 1.07-2.22 and OR = 1.80; 95% CI, 1.13-2.85, respectively).

CONCLUSIONS

The odds of having a triple-negative rather than ER⁺/HER2^- breast cancer is greater for women with type II diabetes, and particularly for those who were users of metformin. This finding is supported by some preclinical data suggesting that diabetes may be more strongly associated with risk of triple-negative disease.

IMPACT

Our study provides novel evidence regarding potential differential effects of type II diabetes and metformin use on risk of different molecular subtypes of breast cancer.

Metformin as an adjuvant in breast cancer treatment

Breast cancer is one of the most common malignancies in females. It is an etiologically complex disease driven by a multitude of cellular pathways. The proliferation and spread of breast cancer is intimately linked to cellular glucose metabolism, given that glucose is an essential cellular metabolic substrate and that insulin signalling has mitogenic effects. Growing interest has focused on anti-diabetic agents in the management of breast cancer. Epidemiologic studies show that metformin reduces cancer incidence and mortality among type 2 diabetic patients. Preclinical in vitro and in vivo research provides intriguing insight into the cellular mechanisms behind the oncostatic effects of metformin. This article aims to provide an overview of the mechanisms in which metformin may elicit its anti-cancerous effects and discuss its potential role as an adjuvant in the management of breast cancer.

Post genome-wide gene-environment interaction study: The effect of genetically driven insulin resistance on breast cancer risk using Mendelian randomization

PURPOSE

The role of insulin resistance (IR) in developing postmenopausal breast cancer has not been thoroughly resolved and may be confounded by lifestyle factors such as obesity. We examined whether genetically determined IR is causally associated with breast cancer risk.

METHODS

We conducted Mendelian randomization (MR) analyses using individual-level data from our previous meta-analysis of a genome-wide association study (GWAS) (n = 11,109 non-Hispanic white postmenopausal women). Four single-nucleotide polymorphisms were associated with fasting glucose (FG), 2 with fasting insulin (FI), and 6 with homeostatic model assessment-IR (HOMA-IR) but were not associated with obesity. We used this GWAS to employ hazard ratios (HRs) for breast cancer risk by adjusting for potential confounding factors.

RESULTS

No direct association was observed between comprising 12 IR genetic instruments and breast cancer risk (HR = 0.93, 95% CI: 0.76-1.14). In phenotype-specific analysis, genetically elevated FG was associated with reduced risk for breast cancer (main contributor of this MR-effect estimate: G6PC2 rs13431652; HR = 0.59, 95% CI: 0.35-0.99). Genetically driven FI and HOMA-IR were not significantly associated. Stratification analyses by body mass index, exercise, and dietary fat intake with combined phenotypes showed that genetically elevated IR was associated with greater breast cancer risk in overall obesity and inactive subgroups (single contributor: MTRR/LOC729506 rs13188458; HR = 2.21, 95% CI: 1.03-4.75).

CONCLUSIONS

We found complex evidence for causal association between IR and risk of breast cancer, which may support the potential value of intervention trials to lower IR and reduce breast cancer risk.

Type 2 Diabetes, but Not Insulin (Analog) Treatment, Is Associated With More Advanced Stages of Breast Cancer: A National Linkage of Cancer and Pharmacy Registries

OBJECTIVE

To investigate whether women with type 2 diabetes (T2D) develop a more advanced stage of breast cancer and whether treatment with insulin (analogs) is associated with specific breast cancer characteristics.

RESEARCH DESIGN AND METHODS

For this nested case-control study, women with breast cancer diagnosed in 2002-2014 were selected from the linked Netherlands Cancer Registry-PHARMO Database Network (N = 33,377). T2D was defined as receiving two or more dispensings of noninsulin blood glucose-lowering drugs prior to breast cancer diagnosis. Women with T2D were matched to women without diabetes. Among women with T2D, insulin users and nonusers were compared. Multivariable ordinal logistic regression was used to investigate the association between T2D/insulin and breast cancer characteristics, including TNM classification (tumor size, lymph node status, metastasis), morphology, grade, estrogen receptor and progesterone receptor (PR), human epidermal growth factor receptor 2, and molecular subtype.

RESULTS

Women with T2D (n = 1,567) were more often diagnosed with a more advanced tumor stage (odds ratio 1.28 [95% CI 13-1.44]) and a higher grade (1.22 [1.08-1.39]) though less often with a PR-negative breast tumor (0.77 [0.67-0.89]) than women without diabetes (n = 6,267). No associations were found for the other breast cancer characteristics. Women with T2D using insulin (n = 388) were not diagnosed with different breast cancer characteristics compared with women with T2D not using insulin (n = 1,179).

CONCLUSIONS

Our study suggests that women with T2D are at increased risk to be diagnosed with a more aggressive type of breast cancer than women without diabetes. No evidence was found that the use of insulin (analogs) is associated with developing more advanced breast cancer tumors.

Effects of different glucose concentrations on the leptin signaling pathway in MCF-7 and T47D breast cancer cells

Aim

Leptin activates multiple intracellular signaling pathways, including JAK/STAT, by binding to its receptor. Leptin is also an important regulator of glucose homeostasis. Although both glucose and leptin increase breast cancer cell proliferation in vitro, whether the enhancing effect of glucose on the proliferation of breast cancer cells is mediated by the leptin signaling pathway is not known. The aim of this study was to investigate the effect of different glucose concentrations on the leptin signaling pathway in MCF-7 and T47D breast cancer cells.

Material and Methods

MCF-7 and T47D cell proliferation in different glucose concentrations (2.5 mM, 5 mM, 25 mM, or 50 mM) were assayed using CCK-8 assay. Leptin, leptin receptors (ObR, ObRb) as well as STAT3 mRNA and protein levels in both cell lines in different glucose concentrations were examined by RT-PCR and western blot, respectively.

Results

Incubation in 2.5 mM, 5 mM, 25 mM, or 50 mM glucose for 72h significantly increased the proliferation of both MCF-7 and T47D cells compared to 0 mM glucose incubated cells (P<0.001). mRNA levels of leptin, ObR, ObRb or STAT3 in 2.5 mM, 5 mM, 25 mM, or 50 mM glucose incubated cells were not significantly different in both cell lines compared to 0 mM (p>0.05). However, ObR protein levels in MCF-7 cells incubated in 25 mM glucose was significantly lower compared to 0 mM glucose by western blot (p<0.05).

Conclusion

Our data suggest that the enhancing effect of glucose on breast cancer cell proliferation is not mediated by the JAK/STAT pathway.

Diabetes, Obesity, and Breast Cancer

The rates of obesity and diabetes are increasing worldwide, whereas the age of onset for both obesity and diabetes are decreasing steadily. Obesity and diabetes are associated with multiple factors that contribute to the increased risk of a number of different cancers, including breast cancer. These factors are hyperinsulinemia, elevated IGFs, hyperglycemia, dyslipidemia, adipokines, inflammatory cytokines, and the gut microbiome. In this review, we discuss the current understanding of the complex signaling pathways underlying these multiple factors involved in the obesity/diabetes-breast cancer link, with a focus particularly on the roles of the insulin/IGF system and dyslipidemia in preclinical breast cancer models. We review some of the therapeutic strategies to target these metabolic derangements in cancer. Future research directions and potential therapeutic strategies are also discussed.

The association of diabetes mellitus and insulin treatment with expression of insulin-related proteins in breast tumors

BACKGROUND

The insulin receptor (INSR) and the insulin growth factor 1 receptor (IGF1R) play important roles in the etiology of both diabetes mellitus and breast cancer. We aimed to evaluate the expression of hormone and insulin-related proteins within or related to the PI3K and MAPK pathway in breast tumors of women with or without diabetes mellitus, treated with or without insulin (analogues).

METHODS

Immunohistochemistry was performed on tumor tissue of 312 women with invasive breast cancer, with or without pre-existing diabetes mellitus, diagnosed in 2000-2010, who were randomly selected from a Danish breast cancer cohort. Women with diabetes were 2:1 frequency matched by year of birth and age at breast cancer diagnosis to those without diabetes. Tumor Microarrays were successfully stained for p-ER, EGFR, p-ERK1/2, p-mTOR, and IGF1R, and scored by a breast pathologist. Associations of expression of these proteins with diabetes, insulin treatment (human insulin and insulin analogues) and other diabetes medication were evaluated by multivariable logistic regression adjusting for menopause and BMI; effect modification by menopausal status, BMI, and ER status was assessed using interactions terms.

RESULTS

We found no significant differences in expression of any of the proteins in breast tumors of women with (n = 211) and without diabetes (n = 101). Among women with diabetes, insulin use (n = 53) was significantly associated with higher tumor protein expression of IGF1R (OR = 2.36; 95%CI:1.02-5.52; p = 0.04) and p-mTOR (OR = 2.35; 95%CI:1.13-4.88; p = 0.02), especially among women treated with insulin analogues. Menopause seemed to modified the association between insulin and IGF1R expression (p = 0.07); the difference in IGF1R expression was only observed in tumors of premenopausal women (OR = 5.10; 95%CI:1.36-19.14; p = 0.02). We found no associations between other types of diabetes medication, such as metformin, and protein expression of the five proteins evaluated.

CONCLUSIONS

In our study, breast tumors of women with pre-existing diabetes did not show an altered expression of selected PI3K/MAPK pathway-related proteins. We observed an association between insulin treatment and increased p-mTOR and IGF1R expression of breast tumors, especially in premenopausal women. This observation, if confirmed, might be clinically relevant since the use of IGF1R and mTOR inhibitors are currently investigated in clinical trials.

Type II Diabetes and Incidence of Estrogen Receptor Negative Breast Cancer in African American Women

White women with type II diabetes (T2D) have an estimated 20% increased risk of developing breast cancer. Little is known about associations by breast cancer subtype or among African American (AA) women, who are disproportionately affected by T2D and estrogen receptor negative (ER-) breast cancer. We assessed the relation of T2D to incidence of ER- and ER+ breast cancer in data from the Black Women's Health Study, a prospective cohort of AA women enrolled in 1995 and followed biennially. During 847,934 person-years of follow-up, there were 1,851 incident invasive breast cancers, including 914 ER+ and 468 ER- cases. Multivariable Cox proportional hazards models were used to compute HRs for breast cancer incidence associated with T2D relative to no T2D, controlling for body mass index (BMI) and other potential confounders. The HR for T2D relative to no T2D was 1.18 [95% confidence interval (CI) 1.00-1.40] for overall breast cancer incidence, with the increase accounted for by ER- cancer: HRs were 1.02 (95% CI, 0.80-1.31) for ER+ and 1.43 (95% CI, 1.03-2.00) for ER- cancer. The HR for T2D and ER- breast cancer was highest among nonobese women (1.92; 95% CI, 1.22-3.04). The findings suggest that AA women with T2D are at increased risk of developing ER- breast cancer and that poor metabolic health may be more important than obesity for this subtype. Given the high prevalence of T2D in AA women, the observed association could, in part, explain racial disparities in incidence of ER- breast cancer. Cancer Res; 77(22); 6462-9. ©2017 AACR.

Demographic Characteristics, Survival and Prognostic Factors of Early Breast Cancer Patients with Type 2 Diabetes Mellitus: A Hospital-Based Cohort Study

Objective: With increasing prevalence of type 2 diabetes mellitus and breast cancer in Iran, we aimed to search hospital registries of breast cancer patients to investigate type 2 diabetes mellitus association with survival outcomes of early breast cancer after adjustment of confounding factors. Methods: In a retrospective cohort study conducted from July 2003 to Feb 2014 and followed up until death or December 2016, female patients with early breast cancer who have been treated for the first time at the Cancer Institute of Iran, were divided to diabetic and non-diabetic groups. Primary and secondary outcomes were relapse free survival (RFS) and overall survival (OS). SPSS version 23 was used for analysis of data. Other variables included age, tumor stage, hormone receptor status, tumor subtype, and patient’s body mass index (BMI). Result: From a total of 1021 patients, 218 (21.4%) had type 2 diabetes mellitus. Diabetic patients had a higher mean age (53.31 vs 47.00), higher mean BMI (31.13 vs 29.15), lower HER2 expression (20.8% vs 32.1%) and higher frequency of luminal A subtype (61.1% vs 51.0). Overall, after adjustment of other variables, diabetes status did not affect RFS or OS independently. However, in luminal A subgroup, patients with diabetes mellitus had significantly lower survival outcomes of OS (135.277 vs 154.701) and RFS (114.107 vs 133.612) as well as OS higher hazard ratio of 1.830 and RFS hazard ratio of 1.663 compared to non-diabetic patients. BMI, hormone receptor status and tumor stage significantly affected the survival of the patients. Conclusion: In the present study, in addition to known breast cancer risk factors, BMI and type 2 diabetes mellitus had an independent impact on survival of the patients, highlighting the importance of health issues such as obesity and diabetes suboptimal performance in the treatment outcomes of early breast cancer patients in Iran.