Tumor microenvironment and breast cancer survival: combined effects of breast fat, M2 macrophages and hyaluronan create a dismal prognosis

Identification of Immune Characteristics of 2 Subtypes of Breast Cancer by Combining Polyamine Metabolism-related Genes to Help With Immunotherapy

This project aims to explore the clustering value of polyamine metabolism-related genes (PMRGs) in breast cancer (BC) to assist treatment. ConsensusClusterPlus R package was employed to cluster BC patients based on the expression of PMRGs. Using the edgeR R package, we analyzed differentially expressed genes (DEGs) of different molecular clusters. Core genes were screened and enriched by the PPI network. Univariate COX was applied to determine genes tightly linked with survival. ConsensusClusterPlus R package was employed to cluster PMRGs. Differences in immune infiltration and expression of immune checkpoints between 2 subgroups were analyzed. Response to immunotherapy was assessed based on the expression level of immunophenoscore (IPS). Drug sensitivity of different PMRG clusters was assessed by pRRophitic R package. We clustered BC patients into 2 different subtypes with different survival rates and biological functions based on the expression of 16 PMRGs. Application of univariate COX analysis identified genes greatly associated with survival and divided BC patients into 2 different PMRG clusters. Patients in the 2 clusters exhibited differences in overall survival rate and immune cell infiltration levels, with multiple immune cells displaying higher immune levels in PMRG cluster 2. PMRG cluster 2 demonstrated higher expression of HLA and IC as well as IPS. Cluster 1 exhibited higher sensitivity to (5Z)-7-Oxozeaenol, 5-Fluorouracil, and 681640, while cluster 2 exhibited higher sensitivity to A-443654 and A-770041. We identified 2 clusters of PMRG with significant differences in the immune microenvironment in BC and predicted potential drugs, aiming to find new directions for clinical treatment of BC.

The Role of Glycocalyx Diversity and Thickness for Nanoparticle Internalization in M1-/M2-like Macrophages

Very small superparamagnetic iron oxide nanoparticles (VSOPs) show diagnostic value in multiple diseases as a promising MRI contrast agent. Macrophages predominantly ingest VSOPs, but the mechanism remains unclear. This study identifies differences in VSOP uptake between pro-inflammatory M1 and anti-inflammatory M2 macrophages and explores the role of the pericellular glycocalyx. Glycosaminoglycans (GAG) synthesis activities and the pericellular glycocalyx for M1/M2-like macrophages were assessed by RT-qPCR, Click-iT reaction, and WGA-FITC staining. The uptake of europium-VSOP and Synomag by the two subtypes was measured using Prussian blue staining, fluorescent microscopy, and magnetic particle spectroscopy. The findings revealed that M2-like macrophages had higher GAG synthesis activity, a thicker glycocalyx, and increased nanoparticle uptake compared to M1-like macrophages. Enzymatic glycocalyx degradation significantly decreased nanoparticle uptake. This study demonstrates a positive correlation between glycocalyx and nanoparticle uptake that could be exploited for imaging and targeted therapy, particularly in cancer, where macrophage subtypes play distinct roles.

Predictive and Prognostic Relevance of Tumor-Infiltrating Immune Cells: Tailoring Personalized Treatments against Different Cancer Types

TIICs are critical components of the TME and are used to estimate prognostic and treatment responses in many malignancies. TIICs in the tumor microenvironment are assessed and quantified by categorizing immune cells into three subtypes: CD66b+ tumor-associated neutrophils (TANs), FoxP3+ regulatory T cells (Tregs), and CD163+ tumor-associated macrophages (TAMs). In addition, many cancers have tumor-infiltrating M1 and M2 macrophages, neutrophils (Neu), CD4+ T cells (T-helper), CD8+ T cells (T-cytotoxic), eosinophils, and mast cells. A variety of clinical treatments have linked tumor immune cell infiltration (ICI) to immunotherapy receptivity and prognosis. To improve the therapeutic effectiveness of immune-modulating drugs in a wider cancer patient population, immune cells and their interactions in the TME must be better understood. This study examines the clinicopathological effects of TIICs in overcoming tumor-mediated immunosuppression to boost antitumor immune responses and improve cancer prognosis. We successfully analyzed the predictive and prognostic usefulness of TIICs alongside TMB and ICI scores to identify cancer's varied immune landscapes. Traditionally, immune cell infiltration was quantified using flow cytometry, immunohistochemistry, gene set enrichment analysis (GSEA), CIBERSORT, ESTIMATE, and other platforms that use integrated immune gene sets from previously published studies. We have also thoroughly examined traditional limitations and newly created unsupervised clustering and deconvolution techniques (SpatialVizScore and ProTICS). These methods predict patient outcomes and treatment responses better. These models may also identify individuals who may benefit more from adjuvant or neoadjuvant treatment. Overall, we think that the significant contribution of TIICs in cancer will greatly benefit postoperative follow-up, therapy, interventions, and informed choices on customized cancer medicines.

Identification of Transcriptomic Signatures of Pancreatic Ductal Adenocarcinoma-Derived Exosomes That Promote Macrophage M2 Polarization and Predict Prognosis: S100A9 Reveals Tumor Progression

Background

Exosomes play a role in intercellular communication and participate in the interaction between pancreatic ductal adenocarcinoma (PDAC) cells and immune cells. Macrophages can receive tumor cell-derived exosomes to polarize into M2-type macrophages, which can enhance the invasion and metastasis of pancreatic cancer, leading to poor prognosis. However, the mechanism by which pancreatic cancer cell-derived exosomes promote M2-type macrophages is still unclear.

Methods

M2 macrophage-associated exosome-derived key module genes were identified by differentially expressed genes (DEGs) and weighted gene co-expression network analysis (WGCNA) analysis using exoRbase 2.0, The Cancer Genome Atlas (TCGA), and The International Cancer Genome Consortium (ICGC) databases. Multivariate Cox regression analysis was used to identify key prognostic genes and obtain regression coefficients to establish prognostic signature. Immune infiltration, tumor mutations, and GSEA among different risk groups were compared. exoRbase 2.0, Gene Expression Profiling Interactive Analysis 2 (GEPIA2), HPA, and TISCH2 databases were used to further analyze the expression pattern of S100A9 in pancreatic cancer. In vitro experiments, cell-derived exosome isolation, quantitative polymerase chain reaction (qPCR), western blot, flow cytometry analysis, cell transfection, transwell assay, and CCK-8 assay were applied to investigate the roles of S100A9 in macrophage M2 polarization and tumor progression.

Results

The key genes of PDAC-derived exosomes promoting M2-type macrophage polarization were identified, and a risk score model was established. The risk score is related to the expression of common immune checkpoints, immune score, and stromal score, and the tumor mutational burden and biological function of high- and low-risk groups were also different. S100A9 was positively correlated with M2-type macrophage marker. In addition, scRNA-seq data from the TISCH2 database revealed that S100A9 is predominantly expressed in pancreatic cancer cells and mono/macrophage cells, suggesting that S100A9 in pancreatic cancer cells could be received by macrophages, thereby inducing macrophage polarization. In vitro, we used exosomes from BxPC-3 cell lines to coculture macrophages and found that macrophages were mainly polarized toward M2 type, which further promoted the proliferation and metastasis of PDAC.

Conclusions

Our study established a reliable risk score model for PDAC-derived exosomes and M2 macrophages, identified the important role of S100A9 in macrophage M2 polarization, which provides a new strategy for the diagnosis and treatment of PDAC, and strengthened the understanding of the mechanism of tumor development and metastasis.

The regulatory role of autophagy between TAMs and tumor cells

Cancer has become a global public health problem and its harmful effects have received widespread attention. Conventional treatments such as surgical resection, radiotherapy and other techniques are applicable to clinical practice, but new drugs are constantly being developed and other therapeutic approaches, such as immunotherapy are being applied. In addition to studying the effects on individual tumor cells, it is important to explore the role of tumor microenvironment on tumor cell development since tumor cells do not exist alone but in the tumor microenvironment. In the tumor microenvironment, tumor cells are interconnected with other stromal cells and influence each other, among which tumor-associated macrophages (TAMs) are the most numerous immune cells. At the same time, it was found that cancer cells have different levels of autophagy from normal cells. In cancer therapy, the occurrence of autophagy plays an important role in promoting tumor cell death or inhibiting tumor cell death, and is closely related to the environment. Therefore, elucidating the regulatory role of autophagy between TAMs and tumor cells may be an important breakthrough, providing new perspectives for further research on antitumor immune mechanisms and improving the efficacy of cancer immunotherapy.

Identification of breast cancer subgroups and immune characterization based on glutamine metabolism-related genes

Immunotherapy is a promising treatment for breast cancer (BC). However, due to individual differences and tumor heterogeneity, immunotherapy is only applicable to some BC patients. Glutamine metabolism plays a role in inhibiting immunotherapy, but its role in BC is limitedly studied. Therefore, we aimed to identify different BC subgroups based on glutamine metabolism and characterize the features of different subgroups to provide guidance for personalized immunotherapy for BC patients. Using unsupervised clustering analysis, we classified BC patients in The Cancer Genome Atlas (TCGA) with glutamine metabolism-related genes and obtained low-risk (LR) and high-risk (HR) subgroups. Survival analysis revealed that prognosis of LR subgroup was notably better than HR subgroup. Through ssGSEA and CIBERSORT methods, we disclosed that infiltration levels of B cells, Mast cells, T helper cells, and Th2 cells, and Type II IFN Response immune function were notably higher in LR subgroup than in HR subgroup. The Wilcox algorithm comparison denoted that DEPTH of LR subgroup was significantly lower than HR subgroup. The TIDE of LR subgroup was significantly higher than HR subgroup. Functional annotation of differentially expressed genes revealed that channel activity and the Estrogen signaling pathway may be related to BC prognosis. Ten hub genes were selected between the subgroups through the STRING database and Cytoscape, and their correlation with drugs was predicted on the CellMiner website. This study analyzed the immune characteristics of BC subgroups based on glutamine metabolism and provided reference for prognosis prediction and personalized immunotherapy.

KDELC2 Upregulates Glioblastoma Angiogenesis via Reactive Oxygen Species Activation and Tumor-Associated Macrophage Proliferation

Glioblastoma is notorious for its rapid progression and neovascularization. In this study, it was found that KDEL (Lys-Asp-Glu-Leu) containing 2 (KDELC2) stimulated vasculogenic factor expression and induced human umbilical vein endothelial cell (HUVEC) proliferation. The NLRP3 inflammasome and autophagy activation via hypoxic inducible factor 1 alpha (HIF-1α) and mitochondrial reactive oxygen species (ROS) production was also confirmed. The application of the NLRP3 inflammasome inhibitor MCC950 and autophagy inhibitor 3-methyladenine (3-MA) indicated that the above phenomenon activation correlated with an endothelial overgrowth. Furthermore, KDELC2 suppression decreased the endoplasmic reticulum (ER) stress factors' expression. The ER stress inhibitors, such as salubrinal and GSK2606414, significantly suppressed HUVEC proliferation, indicating that ER stress promotes glioblastoma vascularization. Finally, shKDELC2 glioblastoma-conditioned medium (CM) stimulated TAM polarization and induced THP-1 cells to transform into M1 macrophages. In contrast, THP-1 cells co-cultured with compensatory overexpressed (OE)-KDELC2 glioblastoma cells increased IL-10 secretion, a biomarker of M2 macrophages. HUVECs co-cultured with shKDELC2 glioblastoma-polarized THP-1 cells were less proliferative, demonstrating that KDELC2 promotes angiogenesis. Mito-TEMPO and MCC950 increased caspase-1p20 and IL-1β expression in THP-1 macrophages, indicating that mitochondrial ROS and autophagy could also interrupt THP-1-M1 macrophage polarization. In conclusion, mitochondrial ROS, ER stress, and the TAMs resulting from OE-KDELC2 glioblastoma cells play important roles in upregulating glioblastoma angiogenesis.

Breast Cancer Survival Outcomes and Tumor-Associated Macrophage Markers: A Systematic Review and Meta-Analysis

INTRODUCTION

Tumor-associated macrophages (TAMs) in breast cancer are associated with a poor prognosis. Early studies of TAMs were largely limited to the pan-macrophage marker CD68, however, more recently, an increasing number of studies have used CD163, a marker expressed by alternatively activated M2 macrophages and TAM subsets. We hypothesized that CD163-positive (CD163+) TAMs would be a better predictor of survival outcomes in breast cancer compared to CD68+  TAMs.

METHODS

We performed a systematic literature search of trials (from 1900 to August 2020) reporting overall survival (OS) or progression-free survival (PFS), breast cancer-specific survival (BCSS), TAM phenotype, and density. Thirty-two studies with 8446 patients were included. Meta-analyses were carried out on hazard ratios (HRs) for survival outcomes of breast cancer patients with a high density of TAMs (CD68+ and/or CD163+) compared to a low density of TAMs.

RESULTS

A high density of TAMs (CD68+ and/or CD163+) was associated with decreased OS (HR 1.69, 95% CI 1.37-2.07) and reduced PFS (HR 1.64; 95% CI 1.35-1.99). Subgrouping by CD marker type showed a lower OS for high density of CD163+ TAMs (HR 2.24; 95% CI 1.71-2.92) compared to a high density of CD68+  TAMs (HR 1.5; 95% CI 1.12-2). A high density of TAMs (CD68+  and/or CD163+) in triple-negative breast cancer (TNBC) cases was associated with lower OS (HR 2.81, 95% CI 1.35-5.84).

CONCLUSION

Compared to CD68+  TAMs, a high density of CD163+ TAMs that express a similar phenotype to M2 macrophages are a better predictor of poor survival outcomes in breast cancer.

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

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

Metabolic Reprogramming of Breast Tumor-Educated Macrophages Revealed by NMR Metabolomics

The metabolic crosstalk between tumor cells and tumor-associated macrophages (TAMs) has emerged as a critical contributor to tumor development and progression. In breast cancer (BC), the abundance of immune-suppressive TAMs positively correlates with poor prognosis. However, little is known about how TAMs reprogram their metabolism in the BC microenvironment. In this work, we have assessed the metabolic and phenotypic impact of incubating THP-1-derived macrophages in conditioned media (CM) from two BC cell lines cultured in normoxia/hypoxia: MDA-MB-231 cells (highly metastatic, triple-negative BC), and MCF-7 cells (less aggressive, luminal BC). The resulting tumor-educated macrophages (TEM) displayed prominent differences in their metabolic activity and composition, compared to control cells (M0), as assessed by exo- and endometabolomics. In particular, TEM turned to the utilization of extracellular pyruvate, alanine, and branched chain keto acids (BCKA), while exhibiting alterations in metabolites associated with several intracellular pathways, including polyamines catabolism (MDA-TEM), collagen degradation (mainly MCF-TEM), adenosine accumulation (mainly MDA-TEM) and lipid metabolism. Interestingly, following a second-stage incubation in fresh RPMI medium, TEM still displayed several metabolic differences compared to M0, indicating persistent reprogramming. Overall, this work provided new insights into the metabolic plasticity of TEM, revealing potentially important nutritional exchanges and immunoregulatory metabolites in the BC TME.

Characterization of Hyaluronan Localization in the Developing Mammary Gland and Mammary Tumors

The extracellular matrix (ECM) is biochemically and biomechanically important for the structure and function of the mammary gland, which undergoes vast structural changes throughout pubertal and reproductive development. Although hyaluronan (HA) is a ubiquitous glycosaminoglycan (GAG) of the mammary gland ECM, extensive characterization of HA deposition in the mammary gland is lacking. Understanding physiologic HA metabolism is critical as this tightly controlled system is often hijacked in cancer. In the current studies, we characterize HA regulation throughout mammary gland development to better understand subsequent dysregulation of HA in mammary tumors. Using immunofluorescence (IF) imaging, we demonstrate that organized HA-rich septa exist in the mammary gland stroma throughout puberty, pregnancy, and involution. Furthermore, we find heterogeneous HA deposition within two murine models of breast cancer. Using cell specific isolation techniques, we characterize expression of genes associated with HA binding, synthesis, and degradation within EpCAM + epithelial cells, CD90.2 + fibroblasts, and F4/80 + macrophages isolated from mammary glands and tumors. Most notably, we identify elevated levels of the hyaluronidases Hyal1 and Hyal2 in tumor-association macrophages (TAMs), suggesting a role for TAM-mediated turnover of HA in the tumor microenvironment (TME). Gene expression is supported functionally by in vitro experiments in which macrophages treated with tumor-cell conditioned media exhibit increased hyaluronidase activity. These findings link TAMs to the direct degradation of HA within the TME of mammary tumors, which has negative implications for patient survival.

The crosstalk within the breast tumor microenvironment in type II diabetes: Implications for cancer disparities

Obesity-driven (type 2) diabetes (T2D), the most common metabolic disorder, both increases the incidence of all molecular subtypes of breast cancer and decreases survival in postmenopausal women. Despite this clear link, T2D and the associated dysfunction of diverse tissues is often not considered during the standard of care practices in oncology and, moreover, is treated as exclusion criteria for many emerging clinical trials. These guidelines have caused the biological mechanisms that associate T2D and breast cancer to be understudied. Recently, it has been illustrated that the breast tumor microenvironment (TME) composition and architecture, specifically the surrounding cellular and extracellular structures, dictate tumor progression and are directly relevant for clinical outcomes. In addition to the epithelial cancer cell fraction, the breast TME is predominantly made up of cancer-associated fibroblasts, adipocytes, and is often infiltrated by immune cells. During T2D, signal transduction among these cell types is aberrant, resulting in a dysfunctional breast TME that communicates with nearby cancer cells to promote oncogenic processes, cancer stem-like cell formation, pro-metastatic behavior and increase the risk of recurrence. As these cells are non-malignant, despite their signaling abnormalities, data concerning their function is never captured in DNA mutational databases, thus we have limited insight into mechanism from publicly available datasets. We suggest that abnormal adipocyte and immune cell exhaustion within the breast TME in patients with obesity and metabolic disease may elicit greater transcriptional plasticity and cellular heterogeneity within the expanding population of malignant epithelial cells, compared to the breast TME of a non-obese, metabolically normal patient. These challenges are particularly relevant to cancer disparities settings where the fraction of patients seen within the breast medical oncology practice also present with co-morbid obesity and metabolic disease. Within this review, we characterize the changes to the breast TME during T2D and raise urgent molecular, cellular and translational questions that warrant further study, considering the growing prevalence of T2D worldwide.

Advances in Intraoperative Flow Cytometry

Flow cytometry is the gold-standard laser-based technique to measure and analyze fluorescence levels of immunostaining and DNA content in individual cells. It provides a valuable tool to assess cells in the G0/G1, S, and G2/M phases, and those with polyploidy, which holds prognostic significance. Frozen section analysis is the standard intraoperative assessment for tumor margin evaluation and tumor resection. Here, we present flow cytometry as a promising technique for intraoperative tumor analysis in different pathologies, including brain tumors, leptomeningeal dissemination, breast cancer, head and neck cancer, pancreatic tumor, and hepatic cancer. Flow cytometry is a valuable tool that can provide substantial information on tumor analysis and, consequently, maximize cancer treatment and expedite patients’ survival.

Breast cancer microenvironment and obesity: challenges for therapy

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

Machine Learning-Devised Immune-Related lncRNA Signature Panel Predicts the Prognosis and Immune Landscape in Breast Cancer Novel IRLP Signature in BRCA

Long noncoding RNAs (lncRNAs) actively participate in breast cancer (BRCA) tumorigenesis via epigenetic mechanisms. Our study identified immune-related lncRNA (irlncRNA) pairs and compiled them into a set of noncoding gene signatures able to stratify subtypes of BRCA associated with variable degrees of survival and immune cell infiltration. A 40 immune-related lncRNA pair (IRLP) signature including 43 irlncRNAs was built, with high sensitivity and specificity for the prediction of survival in different molecular subtypes of BRCA. Results demonstrated that the low-risk group showed a significantly longer survival rate, and this novel IRLP signature was highly associated with survival status, T stage, metastatic disease, and overall stage in BRCA. Immune infiltrating analyses found that the low-risk group has a lower expression level of macrophage M2 and a higher expression level of immunosuppressed biomarkers than the high-risk group. DEirlncRNAs were further proven to be significantly related to the MAPK signaling, Jak-STAT signaling, and ErbB signaling pathways in BRCA. In conclusion, the 40 IRLP signature showed a promising clinical prediction value in the prognosis of different molecular subtypes and immunotherapy response in BRCA, and the underlying mechanism for these IRLPs warrants further investigations.

Mammographic breast density and survival in women with invasive breast cancer

PURPOSE

We explored the under-debate association between mammographic breast density (MBD) and survival.

METHODS

From the Piedmont Cancer Registry, we identified 693 invasive breast cancer (BC) cases. We analyzed the overall survival in strata of MBD through the Kaplan-Meier method. Using the Cox proportional hazards model, we estimated the hazard ratios (HRs) of death; using the cause-specific hazards regression model, we estimated the HRs of BC-related and other causes of death. Models included term for Breast Imaging-Reporting and Data System (BI-RADS) MBD (categorized as BI-RADS 1 and BI-RADS 2-4) and were adjusted for selected patient and tumour characteristics.

RESULTS

There were 102 deaths, of which 49 were from BC. After 5 years, the overall survival was 69% in BI-RADS 1 and 88% in BI-RADS 2-4 (p < 0.01). Compared to BI-RADS 2-4, the HRs of death for BI-RADS 1 were 1.65 (95% CI 1.06-2.58) in the crude model and 1.35 (95% CI 0.84-2.16) in the fully adjusted model. Compared to BI-RADS 2-4, the fully adjusted HRs for BI-RADS 1 were 1.52 (95% CI 0.74-3.13) for BC-related death and 1.83 (95% CI 0.84-4.00) for the other causes of death.

CONCLUSION

Higher MBD is one of the strongest independent risk factors for BC, but it seems not to have an unfavorable impact on survival.

Role of Biological Mediators of Tumor-Associated Macrophages in Breast Cancer Progression

BACKGROUND

Breast cancer (BRCA) has become the most common cancer worldwide. The tumor microenvironment (TME) in the breast exerts a crucial role in promoting BRCA initiation, progression, and metastasis. Tumor-associated macrophages (TAMs) are the primary component of tumor-infiltrating immune cells through biological mediators which convert TME into malignant tumors. Combinations of these biological mediators can promote tumor growth, metastasis, angiogenesis, immune suppression, and limit the anti-tumor activity of conventional chemotherapy and radiotherapy.

OBJECTIVES

The present study aimed to highlight the functions of several biological mediators in the breast which generate TME into malignant tumors. Furthermore, this review offers a rationale for TAM-targeted therapy as a novel treatment strategy for BRCA Results: this review emphasizes TAM-associated biological mediators of TME viz., cancer-associated fibroblasts, endothelial cells, adipocytes, tumor-derived exosomes, extracellular matrix, and other immune cells, which facilitates TME into malignant tumors. Evidence suggests that the increased infiltration of TAMs and elevated expression of TAM-related genes are associated with a poor prognosis of BRCA. Based on these findings, TAM-targeted therapeutic strategies, including inhibitors of CSF-1/CSF-1R, CCL2/CCR2, CCL5-CCR5, bisphosphonate, nanoparticle, and exosomal-targeted delivery have been developed, and are currently being employed in intervention trials.

CONCLUSION

This review concludes the roles of biological mediators of TME interact with TAMs in BRCA that provide a rationale for TAM-targeted therapy as a novel treatment approach for BRCA.

Obesity modulates the immune macroenvironment associated with breast cancer development

Growing evidence demonstrates a strong correlation between obesity and an increased risk of breast cancer, although the mechanisms involved have not been completely elucidated. Some reports have described a crosstalk between adipocytes, cancer cells, and immune cells within the tumor microenvironment, however, it is currently unknown whether obesity can promote tumor growth by inducing systemic alterations of the immune cell homeostasis in peripheral lymphoid organs and adipose tissue. Here, we used the E0771 breast cancer cell line in a mouse model of diet-induced obesity to analyze the immune subpopulations present in the tumors, visceral adipose tissue (VAT), and spleen of lean and obese mice. Our results showed a significant reduction in the frequency of infiltrating CD8⁺ T cells and a decreased M1/M2 macrophage ratio, indicative of the compromised anti-tumoral immune response reported in obesity. Despite not finding differences in the percentage or numbers of intratumoral Tregs, phenotypic analysis showed that they were enriched in CD39⁺, PD-1⁺ and CCR8⁺ cells, compared to the draining lymph nodes, confirming the highly immunosuppressive profile of infiltrating Tregs reported in established tumors. Analysis of peripheral T lymphocytes showed that tumor development in obese mice was associated to a significant increase in the percentage of peripheral Tregs, which supports the systemic immunosuppressive effect caused by the tumor. Interestingly, evaluation of immune subpopulations in the VAT showed that the characteristic increase in the M1/M2 macrophage ratio reported in obesity, was completely reversed in tumor-bearing mice, resembling the M2-polarized profile found in the microenvironment of the growing tumor. Importantly, VAT Tregs, which are commonly decreased in obese mice, were significantly increased in the presence of breast tumors and displayed significantly higher levels of Foxp3, indicating a regulatory feedback mechanism triggered by tumor growth. Altogether, our results identify a complex reciprocal relationship between adipocytes, immune cells, and the tumor, which may modulate the immune macroenvironment that promotes breast cancer development in obesity.

IL-2 Modulates TAMs Derived Exosomal MiRNAs to Ameliorate Hepatocellular Carcinoma Development and Progression

Background. Interleukin-2 (IL-2) is proved to play an irreplaceable role in antitumor regulation in numerous experimental and clinical trials. Tumor-associated macrophages (TAMs) are able to release exosomes to promote the development and progression of hepatocellular carcinoma (HCC) as essential component of microenvironment. In this study, our intention is to explore the effects of the exosomes from TAMs with IL-2 treatment on HCC development. TAMs were collected and cultured from HCC tissues. The exosomes from the TAMs treated with IL-2 (Exo^IL2-TAM) or not (Exo^TAM) were identified and used to treat HCC cells in vivo and in vitro. The proliferation, apoptosis, and metastasis of HCC cells were measured. The changes of miRNAs in exosomes were explored to clarify the possible mechanisms. Both decrease of cell proliferation and metastasis and increase of apoptosis were observed with Exo^IL2-TAM treatment compared with Exo^TAMin vivo and in vitro. miR-375 was obviously augmented in Exo^IL2-TAM and HCC cells treated with Exo^IL2-TAM. Taken together, IL-2 may modulate exosomal miRNAs from TAMs to ameliorate hepatocellular carcinoma development. This study provides a new perspective to explain the mechanism by which IL-2 inhibits hepatocellular carcinoma and implies the potential clinical value of exosomal miRNAs released by TAMs.

Scavenger receptor MARCO contributes to macrophage phagocytosis and clearance of tumor cells

Macrophage receptor with collagenous structure (MARCO) is a member of the class A scavenger receptor family which is expressed on the cell surface of macrophages. It is well known that MARCO avidly binds to unopsonized pathogens, leading to its ingestion by macrophages. However, the role of MARCO in the recognition and phagocytosis of tumor cells by macrophages remains poorly understood. In this study, we used lentiviral technology to knockdown and overexpress MARCO and investigated the ability of macrophages to phagocytose tumor cells. Our results showed that MARCO expression was correlated with the ability of macrophages to carry on phagocytosis. MARCO knockdown led to significant decreases in the number of engulfment pseudopodia of macrophages and inhibition of the phagocytosis of tumor cells. On the other hand, MARCO overexpression elevated activity of SYK, PI3K and Rac1 in macrophages, which led to changes in macrophage morphology and enhanced phagocytosis by promoting formation of stress fibers and pseudopodia. By Co-IP analysis we showed that MARCO directly binds to the β5 integrin of SL4 tumor cells. In summary, these results demonstrated the important role for MARCO in demonstrated tumor cells uptake and clearance by macrophages.

Tumor-associated macrophages in osteosarcoma

Osteosarcoma (OS) is the most common primary bone tumor in children and adolescents. It is an aggressive tumor with a tendency to spread to the lung, which is the most common site of metastasis. Patients with advanced OS with metastases have poor prognoses despite the application of chemotherapy, thus highlighting the need for novel therapeutic targets. The tumor microenvironment (TME) of OS is confirmed to be essential for and supportive of tumor growth and dissemination. The immune component of the OS microenvironment is mainly composed of tumor-associated macrophages (TAMs). In OS, TAMs promote tumor growth and angiogenesis and upregulate the cancer stem cell-like phenotype. However, TAMs inhibit the metastasis of OS. Therefore, much attention has been paid to investigating the mechanism of TAMs in OS development and the progression of immunotherapy for OS. In this article, we aim to summarize the roles of TAMs in OS and the major findings on the application of TAMs in OS treatment.

Construction and Identification of a Novel 5-Gene Signature for Predicting the Prognosis in Breast Cancer

Background: Breast cancer is one of the most common malignancies in women worldwide. The purpose of this study was to identify the hub genes and construct prognostic signature that could predict the survival of patients with breast cancer (BC).

Methods: We identified differentially expressed genes between the responder group and non-responder group based on the GEO cohort. Drug-resistance hub genes were identified by weighted gene co-expression network analysis, and a multigene risk model was constructed by univariate and multivariate Cox regression analysis based on the TCGA cohort. Immune cell infiltration and mutation characteristics were analyzed.

Results: A 5-gene signature (GP6, MAK, DCTN2, TMEM156, and FKBP14) was constructed as a prognostic risk model. The 5-gene signature demonstrated favorable prediction performance in different cohorts, and it has been confirmed that the signature was an independent risk indicater. The nomogram comprising 5-gene signature showed better performance compared with other clinical features, Further, in the high-risk group, high M2 macrophage scores were related with bad prognosis, and the frequency of TP53 mutations was greater in the high-risk group than in the low-risk group. In the low-risk group, high CD8+ T cell scores were associated with a good prognosis, and the frequency of CDH1 mutations was greater in the low-risk group than that in the high-risk group. At the same time, patients in the low risk group have a good response to immunotherapy in terms of immunotherapy. The results of immunohistochemistry showed that MAK, GP6, and TEMEM156 were significantly highly expressed in tumor tissues, and DCTN2 was highly expressed in normal tissues.

Conclusions: Our study may find potential new targets against breast cancer, and provide new insight into the underlying mechanisms.

The tumor microenvironment as driver of stemness and therapeutic resistance in breast cancer: New challenges and therapeutic opportunities

BACKGROUND

Breast cancer (BC), the second most common cause of cancer-related deaths, remains a significant threat to the health and wellness of women worldwide. The tumor microenvironment (TME), comprising cellular components, such as cancer-associated fibroblasts (CAFs), immune cells, endothelial cells and adipocytes, and noncellular components such as extracellular matrix (ECM), has been recognized as a critical contributor to the development and progression of BC. The interplay between TME components and cancer cells promotes phenotypic heterogeneity, cell plasticity and cancer cell stemness that impart tumor dormancy, enhanced invasion and metastasis, and the development of therapeutic resistance. While most previous studies have focused on targeting cancer cells with a dismal prognosis, novel therapies targeting stromal components are currently being evaluated in preclinical and clinical studies, and are already showing improved efficacies. As such, they may offer better means to eliminate the disease effectively.

CONCLUSIONS

In this review, we focus on the evolving concept of the TME as a key player regulating tumor growth, metastasis, stemness, and the development of therapeutic resistance. Despite significant advances over the last decade, several clinical trials focusing on the TME have failed to demonstrate promising effectiveness in cancer patients. To expedite clinical efficacy of TME-directed therapies, a deeper understanding of the TME is of utmost importance. Secondly, the efficacy of TME-directed therapies when used alone or in combination with chemo- or radiotherapy, and the tumor stage needs to be studied. Likewise, identifying molecular signatures and biomarkers indicating the type of TME will help in determining precise TME-directed therapies.

Recent Progress on Immunotherapy for Breast Cancer: Tumor Microenvironment, Nanotechnology and More

Immunotherapy is a major emerging treatment for breast cancer (BC). However, not all breast cancer patients derive benefit from immunotherapy. Predictive biomarkers of immunotherapy, such as tumor mutation burden and tumor-infiltrating lymphocytes, are promising to stratify the patients with BC and optimize the therapeutic effect. Various targets of the immune response pathway have also been explored to expand the modalities of immunotherapy. The use of nanotechnology for the imaging of predictive biomarkers and the combination with other therapeutic modalities presents a number of advantages for the immunotherapy of BC. In this review, we summary the emerging therapeutic modalities of immunotherapy, present prominent examples of immunotherapy in BC, and discuss the future opportunity of nanotechnology in the immunotherapy of BC.

Characteristics of Infiltrating Immune Cells and a Predictive Immune Model for Cervical Cancer

The role of infiltrating immune cells within the tumor microenvironment has received considerable attention, but their function in cervical cancer remains to be elucidated; thus, comprehensive evaluation of their predictive value is needed. Using cervical cancer samples from 406 patients, immune cell infiltration was evaluated via immunohistochemistry. CD3+, CD4+, CD8+, CD20+, CD57+, CD68+, and CD163+ cell infiltration was compared in samples from adjacent tissues and the tumor center. The associations between immune cell distributions in the tumor center, clinicopathological features, and prognosis were correlated among immune cell types. Using three immune features, an immune model was constructed based on a Cox regression analysis with the least absolute shrinkage and selection operator (lasso) penalty to derive immune risk scores.

Immune cells that infiltrated the tumor center correlated with clinicopathological characteristics and prognosis. The immune risk scores were an independent prognostic indicator and were found to predict cervical cancer prognosis as well as the effects of chemoradiotherapy. We classified patients into either high- or low-risk subgroups (namely CD4+^highCD163+^highCD57+^low and CD4+^lowCD163+^lowCD57+^high, respectively) based on their immune scores. Significant differences were found in the 3-year overall survival of patients with high- and low-risk scores (83.0% vs. 96.6%; P < 0.001). High immune risk scores resulted in decreased overall survival for patients in stages IB1+IIA1, IB2+IIA2, and IIB-IV (P = 0.001, P = 0.008, and P = 0.044, respectively). Overall survival was significantly worse following chemoradiotherapy in high-scoring patients in stages IB1+IIA1 and IB2+IIA2 (P = 0.001 and P=0.008, respectively). Moreover, overall survival was significantly worse after radiotherapy or chemotherapy in high-scoring patients in stage IB1+IIA1 (P = 0.03). Our work reveals that the distribution of infiltrating immune cells affects their function in cervical cancer. Our tumor center-centric immune model effectively predicted survival, suggesting its potential use in identifying suitable candidates for chemoradiotherapy.

Three Cases of Bilateral Breast Absence Associated with Familial Congenital Ectodermal Defects

Objective

This study aims to analyze three cases of bilateral breast absence associated with congenital ectodermal defects in the same family to identify a suitable clinical treatment plan.

Methods

Three patients (case 1 and case 2 are a brother–sister relationship; case 3 is their father) complained of the absence of breasts, nipples, and areolas, accompanied by deformity of facial features and fingers; all other clinical indexes were normal. Case 1 first underwent bilateral papillary reconstruction, with areola embroidery carried out six months later. Case 2 first underwent prosthetic breast augmentation, and after ten months, she underwent nipple reconstruction and auricular cartilage, silica gel prosthesis rhinoplasty, epicanthus correction, and areola embroidery. Gene tests were carried out for both cases. Case 3 did not undergo any surgical procedures.

Results

The operations achieved good results, although in case 2, the reconstructed nipples retracted and became smaller. Neither of the subjects had adverse reactions after the procedures. A heterozygous mutation of the KCTD1 gene c.2020A>T (p.i674f), a mutation inherited from case 3 (their father), was detected through gene analysis. Copy number analysis and single-nucleotide polymorphism (SNP) analysis were carried out, but no copy number variation possibly related to clinical manifestations was detected.

Conclusion

The bilateral breast absence associated with familial congenital ectodermal defects in cases 1 and 2 were found to be induced by a heterozygous mutation of the KCTD1 gene c.2020A>T (p.i674f) inherited from case 3 (their father). Two of the three cases underwent surgical treatment, and good clinical results were achieved.

Breast adipose tissue macrophages (BATMs) have a stronger correlation with breast cancer survival than breast tumor stroma macrophages (BTSMs)

Background

An abundance of tumor-associated macrophages has been shown to be an independent prognostic factor for a poor prognosis of human breast cancer (BC). Adipose tissue accounts for the largest proportion of the breast and has also been identified as an independent indicator of poor survival in BC. This study aims to elucidate if the influence of adipose tissue in BC might be mediated by macrophages. The roles of macrophages in the breast tumor-stroma (breast tumor stroma macrophages, BTSM) and macrophages in the surrounding adipose tissue (breast adipose tissue macrophages, BATM) were explored separately.

Methods

Two hundred ninety-eight BC tissue samples were analyzed immunohistochemically. The number of macrophages was detected by CD68+ staining. The quantity of BATMs and BTSMs was correlated to clinical and pathological parameters as well as to disease-free survival (DFS) and overall survival (OS).

Results

The amounts of BATMs and BTSMs strongly correlated with each other (r = 0.5, p = 2.98E−15). The quantity of BTSMs, but not of BATMs, was significantly associated with the BC molecular subtype (p = 0.000011), and all triple-negative BC tumors contained high amounts of BTSMs. BATMs were negatively associated with DFS (p = 0.0332). Both BATMs (p = 0.000401) and BTSMs (p = 0.021) were negatively associated with OS in the Kaplan-Meier analysis, but only BATMs remained an independent factor in the multivariate Cox-regression analysis (HR = 4.464, p = 0.004). Combining prostaglandin E2 receptor 3 (EP3)-expression and the quantity of BATMs, a subgroup with an extremely poor prognosis could be identified (median OS 2.31 years in the “high BATMs/low EP3” subgroup compared to 11.42 years in the most favorable “low BATMs/high EP3” subgroup, p = 0.000002).

Conclusion

Our findings suggest that BTSMs and BATMs seem to be involved differently in BC. Breast adipose tissue might contribute to the aggressiveness of BC via BATMs, which were independently associated with BC survival. BATMs’ role and occurrence might be functionally dependent on EP3, as a combination of both factors was strongly associated with survival. Targeting BATMs—eventually in combination with targeting the EP3-pathway—might be promising for future therapies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-021-01422-x.

Sphingomyelin synthase 2 facilitates M2-like macrophage polarization and tumor progression in a mouse model of triple-negative breast cancer

High infiltration of M2-polarized macrophages in the primary tumor indicates unfavorable prognosis and poor overall survival in the patients with triple-negative breast cancer (TNBC). Thus, reversing M2-polarized tumor-associated macrophages in the tumors has been considered as a potential therapeutic strategy for TNBC. Sphingomyelin synthase 2 (SMS2) is the key enzyme for sphingomyelin production, which plays an important role in plasma membrane integrity and function. In this study we investigated whether SMS2 inhibitor or SMS2 gene knockout could reduce macrophages M2 polarization and tumor progression in a mouse model of TNBC. We showed that SMS2 mRNA expression was linked to immunosuppressive tumor microenvironment and poor prognosis in TNBC patients. The knockout of SMS2 or application of 15w (a specific SMS2 inhibitor) markedly decreased the generation of M2-type macrophages in vitro, and reduced the tumor weight and lung metastatic niche formation in a 4T1-TNBC mouse model. We further demonstrated that the in vivo antitumor efficacy of 15w was accompanied by a multifaceted remodeling of tumor immune environment reflecting not only the suppression of M2-type macrophages but also diminished levels of regulatory T cells and myeloid-derived suppressor cells leading to a dramatically improved infiltration of antitumor CD8+ T lymphocytes. Collectively, our results reveal a novel and important role of SMS2 in the protumorigenic function and may offer a new strategy for macrophage-targeted anticancer therapy.

T cell immunoglobulin and mucin domain protein 3 inhibits glycolysis in RAW 264.7 macrophages through Hexokinase 2

T cell immunoglobulin and mucin domain-3 (Tim-3), an immune checkpoint molecule, plays critical roles in maintaining innate immune homeostasis; however, the mechanisms underlying these roles remain to be determined. Here, we determined that Tim-3 controls glycolysis in macrophages and thus contributes to phenotype shifting. Tim-3 signal blockade significantly increases lactate production by macrophages, but does not influence cell proliferation or apoptosis. Tim-3 attenuates glucose uptake by inhibiting hexokinase 2 (HK2) expression in macrophages. Tim-3-mediated inhibition of macrophage glycolysis and the expression of proinflammatory cytokines, tumour necrosis factor (TNF)-α and interleukin (IL)-1β are reversed by HK2 silencing. Finally, we demonstrated that Tim-3 inhibits HK2 expression via the STAT1 pathway. We have thus discovered a new way by which Tim-3 modulates macrophage function.

Folic acid-modified Exosome-PH20 enhances the efficiency of therapy via modulation of the tumor microenvironment and directly inhibits tumor cell metastasis

High accumulation of hyaluronan (HA) in the tumor microenvironment leads to an increase in the interstitial pressure and reduction perfusion of drugs. Furthermore, high molecular-weight (HMW)-HA suppresses M1 macrophage polarization, enhances M2 polarization, and induces immunosuppression. Hyaluronidase treatment have attempted to decrease the quantity of HA in tumors. However, hyaluronidase-driven HA degradation driven accelerates tumor cell metastasis, which is a major cause of mortality in cancer patients. Thus, we designed a novel exosome-based drug delivery system (DDS), named Exos-PH20-FA, using genetic engineering to express human hyaluronidase (PH20) and self-assembly techniques to modify the exosomes with folic acid (FA). Our results show that Exos-PH20-FA degraded HMW-HA to low-molecular-weight (LMW)-HA. Moreover, LMW-HA polarized macrophages to the M1 phenotype and reduced the number of relevant immunosuppressive immunocytes which changed the immune microenvironment from an immunosuppressive to immunosupportive phenotype. Furthermore, we demonstrated Exos-PH20-FA directly reduced hyaluronidase-induced metastasis of tumor cells. This tumor treatment also allowed an enhanced delivery of chemotherapy by tumor-targeting effect with FA modification. Our findings indicate that Exos-PH20-FA improves tumor treatment efficiency and reduces the side effects of hyaluronidase treatment, namely tumor cell metastasis. This all-in-one exosome-based HA targeting DDS maybe a promising treatment that yields more efficient and safer results.

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High molecular-weight hyaluronan is related to tumor progression.

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The degradation of hyaluronan enhance cancer cell migration and metastasis.

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Folic acid can target tumor and inhibit tumor cell migration.

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Exosomes are ideal carriers for chemotherapeutics, folic acid and hyaluronidase.

Targeting of CD163+ Macrophages in Inflammatory and Malignant Diseases

The macrophage is a key cell in the pro- and anti-inflammatory response including that of the inflammatory microenvironment of malignant tumors. Much current drug development in chronic inflammatory diseases and cancer therefore focuses on the macrophage as a target for immunotherapy. However, this strategy is complicated by the pleiotropic phenotype of the macrophage that is highly responsive to its microenvironment. The plasticity leads to numerous types of macrophages with rather different and, to some extent, opposing functionalities, as evident by the existence of macrophages with either stimulating or down-regulating effect on inflammation and tumor growth. The phenotypes are characterized by different surface markers and the present review describes recent progress in drug-targeting of the surface marker CD163 expressed in a subpopulation of macrophages. CD163 is an abundant endocytic receptor for multiple ligands, quantitatively important being the haptoglobin-hemoglobin complex. The microenvironment of inflammation and tumorigenesis is particular rich in CD163+ macrophages. The use of antibodies for directing anti-inflammatory (e.g., glucocorticoids) or tumoricidal (e.g., doxorubicin) drugs to CD163+ macrophages in animal models of inflammation and cancer has demonstrated a high efficacy of the conjugate drugs. This macrophage-targeting approach has a low toxicity profile that may highly improve the therapeutic window of many current drugs and drug candidates.

Tumor Cell Associated Hyaluronan-CD44 Signaling Promotes Pro-Tumor Inflammation in Breast Cancer

Cancer has been conceptualized as a chronic wound with a predominance of tumor promoting inflammation. Given the accumulating evidence that the microenvironment supports tumor growth, we investigated hyaluronan (HA)-CD44 interactions within breast cancer cells, to determine whether this axis directly impacts the formation of an inflammatory microenvironment. Our results demonstrate that breast cancer cells synthesize and fragment HA and express CD44 on the cell surface. Using RNA sequencing approaches, we found that loss of CD44 in breast cancer cells altered the expression of cytokine-related genes. Specifically, we found that production of the chemokine CCL2 by breast cancer cells was significantly decreased after depletion of either CD44 or HA. In vivo, we found that CD44 deletion in breast cancer cells resulted in a delay in tumor formation and localized progression. This finding was accompanied by a decrease in infiltrating CD206+ macrophages, which are typically associated with tumor promoting functions. Importantly, our laboratory results were supported by human breast cancer patient data, where increased HAS2 expression was significantly associated with a tumor promoting inflammatory gene signature. Because high levels of HA deposition within many tumor types yields a poorer prognosis, our results emphasize that HA-CD44 interactions potentially have broad implications across multiple cancers.

Breast Adipocyte Co-culture Increases the Expression of Pro-angiogenic Factors in Macrophages

Obese individuals with breast cancer have a poorer prognosis and higher risk of metastatic disease vs. non-obese patients. Adipose tissue in obese individuals is characterized by an enhanced macrophage infiltration, creating a microenvironment that favors tumor progression. Here, we demonstrate a role for adipocyte-macrophage interactions in the regulation of angiogenesis. Co-culture of THP-1 macrophages with human breast adipocytes led to increased expression of the pro-angiogenic growth factor, vascular endothelial growth factor A (VEGFA). Several adipocyte-derived proteins including leptin, insulin, IL-6, and TNF-α were each capable of increasing VEGFA expression in THP-1 macrophages, identifying these as possible mediators of the changes that were observed with co-culture. Furthermore, analysis of THP-1 culture media by antibody array revealed that THP-1 secrete several other pro-angiogenic signals in response to adipocyte co-culture, including interleukin 8 (IL-8), matrix metalloproteinase 9 (MMP9), pentraxin 3 (PTX3), and serpin E1 (plasminogen activator inhibitor 1, PAI1) after co-culture with human adipocytes. We used an in vitro endothelial tube formation assay with human vascular endothelial cells to evaluate the effects of THP-1 culture media on angiogenesis. Here, culture media from THP-1 cells previously exposed to human adipocytes stimulated endothelial tube formation more significantly than THP-1 cells cultured alone. In summary, we find that adipocyte co-culture stimulates the expression of pro-angiogenic mediators in macrophages and has pro-angiogenic effects in vitro, thus representing a possible mechanism for the enhanced risk of breast cancer progression in obese individuals.