Clinical management of women with metastatic breast cancer: a descriptive study according to age group

What are the needs in oral antitumor therapy? An analysis of patients' and practitioners' preferences

Background

Since the European approval of CDK4/6 inhibitors in 2016, the treatment of patients with hormone-receptor-positive, HER2-negative metastatic breast cancer has changed significantly. Compared with chemotherapy, endocrine-based therapy has different treatment regimens and is associated with new side effects. Oral therapy aims for optimal drug efficacy and long treatment times while maintaining maximum independence and quality of life resulting in the conservation of medical staff resources.

Methods

A monocentric analysis of therapy preferences of practitioners (25 nurses and physicians) and patients (11 on endocrine monotherapy, 17 on endocrine-based therapy, and 14 on intravenous chemotherapy) was performed using specific questionnaires. Preferences were assessed using a four-point Likert scale or bidirectional response options.

Results

All patients were highly supportive of oral therapy (mean agreement score on the Likert scale 1.3, p < 0.001 vs. all other options) and a consultation interval of 4 weeks (2.0, p = 0.015 vs. 3 weeks). Practitioners also preferred oral therapy (1.4) and visits every 4 weeks (1.6). In general, patients on oral therapies reported higher compatibility of their therapy with daily life than patients on chemotherapy (1.6 and 1.7 vs. 2.6, p = 0.006). Outpatient oncology is the main source of information for all patients, mainly in case of side effects (2.0) and open questions (1.8). Regarding oral antitumor therapy regimens, patients do not show a significant preference for a specific regimen, while practitioners prefer a continuous regimen (1.6) over a 21/7 regimen (21 days on and 7 days off therapy, 2.5). Patients are likely to accept mild side effects (e.g., neutropenia, diarrhea, polyneuropathy, fatigue) and would still adhere to their initial choice of regimen (continuous or 21/7). Only when side effects occur with a severity of CTCAE grade 3 do patients prefer the regimen in which the side effects occur for a shorter period of time.

Conclusion

Patients and practitioners prefer oral antitumor therapy-both continuous and 21/7 regimens-over other application forms. Patient education and proper therapy management, supported by additional tools, contribute to the specific management of side effects and high adherence. This allows quality of life to be maintained during long-term therapy with CDK4/6 inhibitors in patients with metastatic breast cancer.

The Tumor Immune Microenvironment in Breast Cancer Progression

BACKGROUND

The tumor microenvironment significantly influences breast cancer development, progression, and metastasis. Various immune cell populations, including T cells, B cells, NK cells, and myeloid cells exhibit diverse functions in different breast cancer subtypes, contributing to both anti-tumor and pro-tumor activities.

PURPOSE

This review provides an overview of the predominant immune cell populations in breast cancer subtypes, elucidating their suppressive and prognostic effects. We aim to outline the role of the immune microenvironment from normal breast tissue to invasive cancer and distant metastasis.

METHODS

A comprehensive literature review was conducted to analyze the involvement of immune cells throughout breast cancer progression.

RESULTS

In breast cancer, tumors exhibit increased immune cell infiltration compared to normal tissue. Variations exist across subtypes, with higher levels observed in triple-negative and HER2+ tumors are linked to better survival. In contrast,  ER+ tumors display lower immune infiltration, associated with poorer outcomes. Furthermore, metastatic sites commonly exhibit a more immunosuppressive microenvironment.

CONCLUSION

Understanding the complex interaction between tumor and immune cells during breast cancer progression is essential for future research and the development of immune-based strategies. This comprehensive understanding may pave the way for more effective treatment approaches and improved patients outcomes.

Unique macrophage phenotypes activated by BMP signaling in breast cancer bone metastases

Metastatic breast cancer (mBC) tissue in bone was systematically profiled to define the composition of the tumor microenvironment. Gene expression identified a high myeloid signature of patients with improved survival outcomes. Bone metastases were profiled by spatial proteomics to examine myeloid populations within the stroma that correlated with macrophage functions. Single-cell spatial analysis uncovered macrophage activation in the stroma of mBC bone lesions. Matched BC patient samples of primary breast tumor and bone metastasis tissues were compared for gene expression in the bone, where bone morphogenetic protein 2 (BMP2) was most significantly upregulated. Immune cell changes from breast to bone demonstrated a loss of lymphoid cells but a consistent population of macrophages. BMP-activated macrophages were increased uniquely in bone. Bone marrow-derived macrophage activation coupled with BMP inhibition increased inflammatory responses. Using experimental mouse models of mBC bone metastasis and trained immunity, we found that BMP inhibition restricts progression of metastases early in the macrophage activation state but not after tumors were established in the bone. This study revealed unique myeloid BMP activation states that are distinctly integrated with bone metastases.

Pain associated with breast cancer: etiologies and therapies

Pain associated with breast cancer is a prevalent problem that negatively affects quality of life. Breast cancer pain is not limited to the disease course itself but is also induced by current therapeutic strategies. This, combined with the increasing number of patients living with breast cancer, make pain management for breast cancer patients an increasingly important area of research. This narrative review presents a summary of pain associated with breast cancer, including pain related to the cancer disease process itself and pain associated with current therapeutic modalities including radiation, chemotherapy, immunotherapy, and surgery. Current pain management techniques, their limitations, and novel analgesic strategies are also discussed.

Tailoring Near-Infrared-IIb Fluorescence of Thulium(III) by Nanocrystal Structure Engineering

Currently, mainstream lanthanide probes with fluorescence located in the second near-infrared subwindow of 1500-1700 nm (NIR-IIb) are predominantly Er(III)-based nanoparticles (NPs). Here we report a newly developed NIR-IIb fluorescent nanoprobe, α-Tm NP (cubic-phase NaYF4@NaYF4:Tm@NaYF4), with an emission at 1630 nm. We activate the 1630 nm emission of Tm(III) in α-Tm NP through the large spread of the Stark split sublevels induced by the crystal-field effect of the α-NaYF4 host. Further, we systematically investigated the effect of crystalline structure of the host NaYF4 NP (cubic phase (α) or hexagonal phase (β)), the type and concentrations of dopants (Yb(III), Tm(III), and Ca(II) ions) in the α-phase host, and the thicknesses of the interlayer and inert shell on the NIR-IIb fluorescence of Tm(III). The ultimate nanostructure presents a significant enhancement factor of the NIR-IIb photoluminescence intensity of Tm(III) up to ∼315. With this bright NIR-IIb fluorescent nanoprobe, we demonstrate high-spatial-resolution time-coursing imaging of breast cancer bone metastasis.

Metastasis, characteristic, and treatment of breast cancer in young women and older women: A study from the Surveillance, Epidemiology, and End Results registration database

BACKGROUND

Younger age is an independent risk factor for breast cancer (BC) prognosis, and BC in young women is often considered more aggressive. BC patients with different age and molecular subtypes have different metastasis patterns and survival. Herein, we aim to explore the metastasis patterns, characteristics and treatment methods of young patients with BC, and to compare them with older patients.

METHODS

Data of young patients (aged ≤40 years old) and older patients (aged >40 years old) with BC were extracted from the Surveillance, Epidemiology, and End Results (SEER) registration database in 2010-2019 in this retrospective cohort study. Univariate and multivariate competing risk models and proportional hazard models were used to explore the association between different metastasis patterns and treatments and BC prognoses in young and older patients. Kaplan-Meier (KM) curves were drawn to reflect the survival probability of patients with BC who have different metastasis patterns. Also, we performed subgroup analysis of different metastasis patterns to explore the association between different treatments and overall survival (OS)/cancer specific survival (CSS) in patients with BC. The evaluation index was hazard ratios (HRs) with 95% confidence intervals (CIs).

RESULTS

Totally, 5,984 patients died, and 92.56% of them died from BC. There were respectively 1,089 young patients and 9,105 older patients, and we found some differences of characteristics and metastasis patterns between them. After adjusting for covariates, young patients who had brain metastasis and multiple sites metastasis seemed to have high risk of both lower OS and CSS. Among older patients with BC, brain metastasis, liver metastasis, and multiple sites metastasis were all positively associated with both lower OS and CSS. In young and older patients, those who not receive radiotherapy or surgery, or received non-surgery combined with radiotherapy seemed to have high risk of both lower OS and CSS. Breast-conserving surgery (BCS) and surgery combined with radiotherapy were associated with higher OS and CSS in young patients, while only older patients received surgery combined with radiotherapy had higher OS and CSS. Results of subgroup analysis indicated that for patients with different metastasis patterns, developing a personalized treatment plan is necessary.

CONCLUSIONS

Characteristics of BC between young patients and older patients were different. Clinicians should focus on different metastasis sites and choose appropriate treatments in patients with different ages, which may improve the prognoses.

Aberrant expression of bone morphogenetic proteins in the disease progression and metastasis of breast cancer

Background

Bone morphogenetic proteins (BMPs) play crucial roles in the tumorigenesis and metastasis of cancers. Controversy remains about the exact implications of BMPs and their antagonists in breast cancer (BC), due to their diverse and complex biological functions and signalling. A comprehensive study of the whole family and their signalling in breast cancer is provoked.

Methods

Aberrant expression of BMP, BMP receptors and antagonists in primary tumours in breast cancer were analysed by using TCGA-BRCA and E-MTAB-6703 cohorts. Related biomarkers including ER, HER, proliferation, invasion, angiogenesis, lymphangiogenesis and bone metastasis were involved to identify the relationship with BMPs in breast cancer.

Results

The present study showed BMP8B was significantly increased in breast tumours, while BMP6 and ACVRL1 were decreased in breast cancer tissues. The expressions of BMP2, BMP6, TGFBR1 and GREM1 were significantly correlated with BC patients' poor overall survival. Aberrant expression of BMPs, together with BMP receptors, were explored in different subtypes of breast cancer according to ER, PR and HER2 status. Furthermore, higher levels of BMP2, BMP6 and GDF5 were revealed in triple negative breast cancer (TNBC) whilst BMP4, GDF15, ACVR1B, ACVR2B and BMPR1B were relatively higher in Luminal type BC. ACVR1B and BMPR1B were positively correlated with ERα but were inversely correlated with ERβ. High expression of GDF15, BMP4 and ACVR1B were associated with poorer overall survival in HER2 positive BC. BMPs also play dual roles in tumour growth and metastasis of BC.

Conclusion

A shift pattern of BMPs was showed in different subtypes of breast cancer suggesting a subtype specific involvement. It provokes more research to shed light on the exact role of these BMPs and receptors in the disease progression and distant metastasis through a regulation of proliferation, invasion and EMT.

Incidence and prognostic significance of receptor discordance between primary breast cancer and paired bone metastases

ER, PgR and HER-2 status are the cornerstones of choosing systemic therapy for breast cancer, but can change during the disease course. Guidelines recommended the biopsy of the metastatic tumor to reassess receptor status. Bone is the most frequent metastatic site of breast cancer but remained technically difficult to biopsy. Our study aimed to evaluate the incidence and prognostic significance of receptor discordance between primary breast cancer and paired bone metastases. One hundred and fifty-five breast cancer patients were diagnosed with pathology-confirmed bone metastasis at Fudan University Shanghai Cancer Center. Ninety-three patients with receptor status available on both primary tumor and bone metastases were included in our study. ER, PgR and HER-2 status converted from positive to negative in 10.8% (10/93), 28.0% (26/93) and 8.6% (8/93) of the patients, while ER, PgR and HER-2 status converted from negative to positive in 3.2% (3/93), 4.3% (4/93) and 1.1% (1/93) of the patients, respectively. 40.4% (17/42) of the HER2-0 tumors converted to HER2-low, which enabled them to receive the treatment of new antibody-drug conjugates (ADCs). Prior endocrine and anti-HER2 therapy were the independent risk factors for receptor conversion. Loss of HR expression in bone metastases was significantly associated with worse first-line PFS (adjusted hazard ratio = 3.271, P-value = .039) and OS (adjusted hazard ratio = 6.09, P-value = .011). In conclusion, our study confirmed that patients may experience receptor conversion between primary breast cancer and bone metastases, possibly influenced by prior treatments, which significantly influenced prognosis. The rebiopsy of bone metastases in patients with primary HER2-0 tumors may benefit from the new ADC drugs.

Exosomes from LSD1 knockdown breast cancer cells activate osteoclastogenesis and inhibit osteoblastogenesis

Bone metastasis is a common and incurable complication of breast cancer. Lysine-specific demethylase 1 (LSD1), a histone demethylase, plays an important role in the metastasis of breast cancer. However, the role of LSD1 in bone metastasis of breast cancer is unclear. We hypothesized that exosomes from LSD1 knockdown breast cancer cells promote bone metastasis by remodeling bone microenvironment. To verify this hypothesis, exosomes from LSD1 knockdown Estrogen receptor-positive cancer cell lines, MCF7 and T47D, were isolated, and the effects of these exosomes on osteoblast and osteoclast differentiation were investigated. Interestingly, exosomes from LSD1 knockdown breast cancer cells inhibited osteoblast differentiation and promoted osteoclast differentiation. Mechanistically, miR-6881-3p was decreased in the exosomes from LSD1 knockdown cells, and miR-6881-3p suppressed the expression of pre-B-cell leukemia homeobox 1 (PBX1) and additional sex combs like-2 (ASXL2), two genes with essential functions in osteoblast and osteoclast differentiations respectively. Transfection of miR-6881-3p into LSD1 knockdown cells reversed the effects of the exosomes on osteoblast and osteoclast differentiations. Our study reveals important roles of LSD1 on the regulation of exosomal miRNAs and the formation of favorable bone microenvironment for metastasis.

Metastasis patterns and prognosis in young breast cancer patients: A SEER database analysis

Background

There are few studies on young patients with metastatic breast cancer (MBC). This study aims to explore the metastasis pattern and prognosis of young patients with MBC.

Methods

A total of 6,336 MBC patients diagnosed in the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2015 were selected. They were divided into two age groups: the younger group (≤40 years old) and the older group (>40 years old). χ² test was used to compare clinicopathological characteristics. Survival differences were compared by Kaplan–Meier analysis. Cox regression models were used to determine the prognostic factors affecting survival. Propensity score matching (PSM) was performed to balance the effects of baseline clinicopathological differences.

Results

Finally, 494 patients (7.8%) who are ≤40 years old and 5,842 patients (92.2%) who are >40 years old were included. In the younger group, the proportion of liver metastasis was significantly higher than that in the older group; the proportion of lung metastasis was significantly lower than that of the older group. Kaplan–Meier analysis showed that the younger group had the best prognosis and the older group had the worst. Youth is an independent protective factor for overall survival (OS). In the younger group, liver metastasis had the best prognosis among all metastatic sites, and the HER2-enriched subtype had the best prognosis among all subtypes.

Conclusions

The disease in young MBC patients is more aggressive but has a better prognosis, especially in liver metastases and the HER2-enriched subtypes.

Imaging of Bone Metastases in Breast Cancer

Bone metastases are a common site of spread in advanced breast cancer and responsible for morbidity and high health care costs. Imaging contributes to staging and response assessment of the skeleton and has been instrumental in guiding patient management for several decades. Historically this has been with radiographs, computed tomography and bone scans. More recently, molecular and hybrid imaging methods have undergone significant development, including the addition of single photon emission computed tomography/computed tomography to the bone scan, positron emission tomography, with bone-specific and tumor-specific tracers, and magnetic resonance imaging with complementary functional diffusion-weighted imaging. These have allowed different aspects of the abnormal biology associated with bone metastases to be explored. There is ability to interrogate the bone microenvironment with bone-specific tracers and cancer cell characteristics with tumor-specific methods that complement morphological appearances on computed tomography or magnetic resonance imaging. Alongside the advent of novel, more effective and nuanced therapies for bone metastases in breast cancer, there is accumulating evidence that the developments in imaging allow more sensitive and specific detection of bone metastases as well as more accurate and earlier assessment of treatment response leading to improvements in patient management.

Clinical Characteristics, Prognostic Factors and Treatment Outcomes of Patients with Bone-Only Metastatic Breast Cancer

Introduction

Bone is the most frequent site of breast cancer metastasis. Differences between those who present with de novo bone-only metastasis (BOM) and those who progress to bone-only disease following a diagnosis of early-stage breast cancer are not clear. Such differences in clinical course might have an impact on the aggressiveness of treatment. This study presents the clinical and pathological features, along with treatment outcomes, of breast cancer patients with BOM in relation to the timing and type of bone metastasis.

Patients and Methods

Patients with breast cancer and BOM were retrospectively reviewed. De novo BOM was defined as bone metastasis diagnosed at presentation or within the first 4 months of follow-up. Treatment outcomes of patients with de novo, compared to those with subsequent BOM, are presented.

Results

242 patients, median age (range) at diagnosis was 52 (27–80) years were enrolled. The majority of the patients (77.3%) had de novo BOM with multiple sites of bone involvement (82.6%). At a median follow-up of 37.7 months, the median overall survival (OS) for patients with de novo BOM disease was significantly shorter than those who developed so subsequently; 40.8 months (95% CI, 51.1–184.1) compared to 80.9 months (95% CI, 36.4–47.9), p < 0.001. Tumor grade, hormone receptor status and type of bone lesions (lytic versus sclerotic) had a significant impact on survival outcomes.

Conclusion

Breast cancer with de novo BOM is a distinct clinical entity with unfavorable prognosis and is associated with shorter survival. Several risk factors for poor outcomes were identified and might inform treatment plans.

Genome-wide expression reveals potential biomarkers in breast cancer bone metastasis

Breast cancer metastases are most commonly found in bone, an indication of poor prognosis. Pathway-based biomarkers identification may help elucidate the cellular signature of breast cancer metastasis in bone, further characterizing the etiology and promoting new therapeutic approaches. We extracted gene expression profiles from mouse macrophages from the GEO dataset, GSE152795 using the GEO2R webtool. The differentially expressed genes (DEGs) were filtered by log2 fold-change with threshold 1.5 (FDR < 0.05). STRING database and Enrichr were used for GO-term analysis, miRNA and TF analysis associated with DEGs. Autodock Vienna was exploited to investigate interaction of anti-cancer drugs, Actinomycin-D and Adriamycin. Sensitivity and specificity of DEGs was assessed using receiver operating characteristic (ROC) analyses. A total of 61 DEGs, included 27 down-regulated and 34 up-regulated, were found to be significant in breast cancer bone metastasis. Major DEGs were associated with lipid metabolism and immunological response of tumor tissue. Crucial DEGs, Bcl3, ADGRG7, FABP4, VCAN, and IRF4 were regulated by miRNAs, miR-497, miR-574, miR-138 and TFs, CCDN1, STAT6, IRF8. Docking analysis showed that these genes possessed strong binding with the drugs. ROC analysis demonstrated Bcl3 is specific to metastasis. DEGs Bcl3, ADGRG7, FABP4, IRF4, their regulating miRNAs and TFs have strong impact on proliferation and metastasis of breast cancer in bone tissues. In conclusion, present study revealed that DEGs are directly involved in of breast tumor metastasis in bone tissues. Identified genes, miRNAs, and TFs can be possible drug targets that may be used for the therapeutics. However, further experimental validation is necessary.

Stress in Metastatic Breast Cancer: To the Bone and Beyond

Simple Summary

Breast cancer is the most common cancer affecting women of all ages worldwide. In spite of the encouraging advances made in early diagnosis, 10% of breast cancer patients are still affected with metastatic breast cancer at the time of diagnosis. The available therapeutic options are predominantly palliative, and thus this unfavourable prognosis is associated with a low survival rate. Intriguingly, stress has been shown to promote the growth of breast tumours and the incidence of metastasis. Herein, we describe the contribution of the sympathetic hyperactivation induced by stress to the progression of breast cancer and its dissemination to distant organs, specifically to the bone, but also to the lung, liver and brain. The putative sympathetic adrenergic signalling mechanisms responsible for this modulation are also summarised. The knowledge gathered highlights the therapeutic potential of targeting sympathetic signalling to tackle cancer progression and metastasis.

Abstract

Breast cancer (BRCA) remains as one the most prevalent cancers diagnosed in industrialised countries. Although the overall survival rate is high, the dissemination of BRCA cells to distant organs correlates with a significantly poor prognosis. This is due to the fact that there are no efficient therapeutic strategies designed to overcome the progression of the metastasis. Over the past decade, critical associations between stress and the prevalence of BRCA metastases were uncovered. Chronic stress and the concomitant sympathetic hyperactivation have been shown to accelerate the progression of the disease and the metastases incidence, specifically to the bone. In this review, we provide a summary of the sympathetic profile on BRCA. Additionally, the current knowledge regarding the sympathetic hyperactivity, and the underlying adrenergic signalling pathways, involved on the development of BRCA metastasis to distant organs (i.e., bone, lung, liver and brain) will be revealed. Since bone is a preferential target site for BRCA metastases, greater emphasis will be given to the contribution of α2- and β-adrenergic signalling in BRCA bone tropism and the occurrence of osteolytic lesions.

MicroRNAs: Emerging Regulators of Metastatic Bone Disease in Breast Cancer

Bone metastasis is a frequent complication in patients with advanced breast cancer. Once in the bone, cancer cells disrupt the tightly regulated cellular balance within the bone microenvironment, leading to excessive bone destruction and further tumor growth. Physiological and pathological interactions in the bone marrow are mediated by cell-cell contacts and secreted molecules that include soluble proteins as well as RNA molecules. MicroRNAs (miRNAs) are short non-coding RNAs that post-transcriptionally interfere with their target messenger RNA (mRNA) and subsequently reduce protein abundance. Since their discovery, miRNAs have been identified as critical regulators of physiological and pathological processes, including breast cancer and associated metastatic bone disease. Depending on their targets, miRNAs can exhibit pro-tumorigenic or anti-tumorigenic functions and serve as diagnostic and prognostic biomarkers. These properties have encouraged pre-clinical and clinical development programs to investigate miRNAs as biomarkers and therapeutic targets in various diseases, including metastatic cancers. In this review, we discuss the role of miRNAs in metastatic bone disease with a focus on breast cancer and the bone microenvironment and elaborate on their potential use for diagnostic and therapeutic purposes in metastatic bone disease and beyond.

Breast Cancer Xenograft Murine Models

Mice are used as model organisms to understand the pathological basis of a variety of human diseases, including breast cancer. Both immunocompetent and immunocompromised mouse models are used depending on the scope of the study. Immunocompetent models allow the study of the impact of the immune system in murine models of mammary cancer, while immunodeficient mice serve as ideal host organisms to understand the behavior of human breast cancers within a biological system. Xenografting of human breast cancer cells into immunocompromised mouse models continues to be the most used fundamental animal model in preclinical breast cancer research. These in vivo models allow critical understanding of tumor biology and assessment of novel treatments, a necessary prelude to testing new drugs in the clinic. In this chapter, we provide detailed methodology for the use of non-obese diabetic (NOD) severe combined immunodeficient (SCID) mice in several breast cancer xenografting procedures, including established cell lines and patient-derived xenografts (PDXs).

Metastasis patterns and prognosis in breast cancer patients aged ≥ 80 years: a SEER database analysis

Background: This study aimed to investigate the metastasis patterns and prognosis of breast cancer (BC) in patients aged ≥ 80 years with distant metastases, as the current literature lacks studies in this population.

Methods: A retrospective, population-based study using data from the Surveillance, Epidemiology, and End Results (SEER) database was conducted to evaluate 36,203 patients with BC from 2010 to 2016. Patients were classified into three groups, the older group (aged ≥ 80 years), middle-aged group (aged 60-79 years), and younger group (aged < 60 years). The role of age at the time of BC diagnosis in metastasis patterns was investigated, and the survival of different age groups of patients with BC was assessed.

Results: Overall, 4,359 (12%) patients were diagnosed with BC at age ≥ 80 years, 19,688 (54%) at 60-79 years, and 12,156 (34%) at < 60 years. Compared with the other two groups, those in the older group had a lower rate of treatment acceptance. Statistical analysis revealed that older patients were more likely to have lung invasion only (odds ratio [OR]: 1.274, 95% confidence interval [CI]: 1.163-2.674) and less likely to have bone invasion only (OR: 0.704, 95% CI: 0.583-0.851), brain invasion only (OR: 0.329, 95% CI: 0.153-0.706), or multiple metastatic sites (OR: 0.361, 95% CI: 0.284-0.458) compared to the other two groups. Age at diagnosis was an independent prognostic factor for survival. The older group had the worst overall survival (OS, P<0.001) and BC-specific survival (CSS, P<0.001). Furthermore, patients aged ≥ 80 years with only liver metastasis had the worst CSS and OS.

Conclusion: Patients aged ≥ 80 years were less likely to be receptive to cancer-related therapy and had the highest cancer mortality rate among all patients. Our findings will hopefully help clinicians develop more appropriate modalities of cancer treatment in elderly BC patients.

Exosomal miR-19a and IBSP cooperate to induce osteolytic bone metastasis of estrogen receptor-positive breast cancer

Bone metastasis is an incurable complication of breast cancer. In advanced stages, patients with estrogen-positive tumors experience a significantly higher incidence of bone metastasis (>87%) compared to estrogen-negative patients (<56%). To understand the mechanism of this bone-tropism of ER+ tumor, and to identify liquid biopsy biomarkers for patients with high risk of bone metastasis, the secreted extracellular vesicles and cytokines from bone-tropic breast cancer cells are examined in this study. Both exosomal miR-19a and Integrin-Binding Sialoprotein (IBSP) are found to be significantly upregulated and secreted from bone-tropic ER+ breast cancer cells, increasing their levels in the circulation of patients. IBSP is found to attract osteoclast cells and create an osteoclast-enriched environment in the bone, assisting the delivery of exosomal miR-19a to osteoclast to induce osteoclastogenesis. Our findings reveal a mechanism by which ER+ breast cancer cells create a microenvironment favorable for colonization in the bone. These two secreted factors can also serve as effective biomarkers for ER+ breast cancer to predict their risks of bone metastasis. Furthermore, our screening of a natural compound library identifies chlorogenic acid as a potent inhibitor for IBSP-receptor binding to suppress bone metastasis of ER+ tumor, suggesting its preventive use for bone recurrence in ER+ patients.

dSPIC: a deep SPECT image classification network for automated multi-disease, multi-lesion diagnosis

BACKGROUND

Functional imaging especially the SPECT bone scintigraphy has been accepted as the effective clinical tool for diagnosis, treatment, evaluation, and prevention of various diseases including metastasis. However, SPECT imaging is brightly characterized by poor resolution, low signal-to-noise ratio, as well as the high sensitivity and low specificity because of the visually similar characteristics of lesions between diseases on imaging findings.

METHODS

Focusing on the automated diagnosis of diseases with whole-body SPECT scintigraphic images, in this work, a self-defined convolutional neural network is developed to survey the presence or absence of diseases of concern. The data preprocessing mainly including data augmentation is first conducted to cope with the problem of limited samples of SPECT images by applying the geometric transformation operations and generative adversarial network techniques on the original SPECT imaging data. An end-to-end deep SPECT image classification network named dSPIC is developed to extract the optimal features from images and then to classify these images into classes, including metastasis, arthritis, and normal, where there may be multiple diseases existing in a single image.

RESULTS

A group of real-world data of whole-body SPECT images is used to evaluate the self-defined network, obtaining a best (worst) value of 0.7747 (0.6910), 0.7883 (0.7407), 0.7863 (0.6956), 0.8820 (0.8273) and 0.7860 (0.7230) for accuracy, precision, sensitivity, specificity, and F-1 score, respectively, on the testing samples from the original and augmented datasets.

CONCLUSIONS

The prominent classification performance in contrast to other related deep classifiers including the classical AlexNet network demonstrates that the built deep network dSPIC is workable and promising for the multi-disease, multi-lesion classification task of whole-body SPECT bone scintigraphy images.

Mechanisms Supporting the Use of Beta-Blockers for the Management of Breast Cancer Bone Metastasis

Simple Summary

Bone represents the most common site of metastasis for breast cancer and the establishment and growth of metastatic cancer cells within the skeleton significantly reduces the quality of life of patients and their survival. The interplay between sympathetic nerves and bone cells, and its influence on the process of breast cancer bone metastasis is increasingly being recognized. Several mechanisms, all dependent on β-adrenergic receptor signaling in stromal bone cells, were shown to promote the establishment of disseminated cancer cells into the skeleton. This review provides a summary of these mechanisms in support of the therapeutic potential of β-blockers for the early management of breast cancer metastasis.

Abstract

The skeleton is heavily innervated by sympathetic nerves and represents a common site for breast cancer metastases, the latter being the main cause of morbidity and mortality in breast cancer patients. Progression and recurrence of breast cancer, as well as decreased overall survival in breast cancer patients, are associated with chronic stress, a condition known to stimulate sympathetic nerve outflow. Preclinical studies have demonstrated that sympathetic stimulation of β-adrenergic receptors in osteoblasts increases bone vascular density, adhesion of metastatic cancer cells to blood vessels, and their colonization of the bone microenvironment, whereas β-blockade prevented these events in mice with high endogenous sympathetic activity. These findings in preclinical models, along with clinical data from breast cancer patients receiving β-blockers, support the pathophysiological role of excess sympathetic nervous system activity in the formation of bone metastases, and the potential of commonly used, safe, and low-cost β-blockers as adjuvant therapy to improve the prognosis of bone metastases.

Harnessing the power of antibodies to fight bone metastasis

Antibody-based therapies have proved to be of great value in cancer treatment. Despite the clinical success of these biopharmaceuticals, reaching targets in the bone microenvironment has proved to be difficult due to the relatively low vascularization of bone tissue and the presence of physical barriers. Here, we have used an innovative bone-targeting (BonTarg) technology to generate a first-in-class bone-targeting antibody. Our strategy involves the use of pClick antibody conjugation technology to chemically couple the bone-targeting moiety bisphosphonate to therapeutic antibodies. Bisphosphonate modification of these antibodies results in the delivery of higher conjugate concentrations to the bone metastatic niche, relative to other tissues. In xenograft mice models, this strategy provides enhanced inhibition of bone metastases and multiorgan secondary metastases that arise from bone lesions. Specific delivery of therapeutic antibodies to the bone, therefore, represents a promising strategy for the treatment of bone metastatic cancers and other bone diseases.

Intramedullary rod failure in metastatic breast cancer: Do triple negative cancer patients have more revision surgery?

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Intramedullary rodding can be considered for bone lesions in breast cancer.

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No difference in revision rate among patients with different receptor-status.

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Mean intramedullary rod revision time was 19 months.

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Revision cumulative incidence: 6% at 12 months and 20% at 60 months.

Background

Breast cancer is the most common cancer and second cause of death in women worldwide. Patients with breast cancer are classified into subgroups based on the presence or absence of hormone receptors and the human epidermal growth factor 2-neu (HER-2) marker, the different molecular profiles come with an associated prognosis and variety of possible treatment options. Patients with triple negative cancer have a worse prognosis, a more aggressive behavior, higher likelihood of spreading, a higher risk of recurrence and a poorer outcome overall. Intramedullary rod fixation has proven to provide a good outcome and function in patients with metastatic breast cancer, but no study has addressed the receptor-status potential outcome differences that may affect disease progression at an orthopaedic surgery site.

Questions/Purposes

(1) Do patients with triple negative breast cancer have a higher revision rate of intramedullary rod fixation of bone metastases? (2) Do patients with metastatic triple negative breast cancer have a higher revision rate of intramedullary rod fixation due to local disease progression?

Methods

This was a single-center, observational, retrospective cohort study. Fifty-seven patients with a diagnosis of breast cancer metastatic to long bones who underwent surgical fixation with an intramedullary rod for a pathological fracture or an impending fracture due to a bone metastasis with a Mirels’ score equal or above 8 between January 2004 and December 2016 at our institution were included. All implants used were from the same manufacturer (Stryker Corp., Mahwah, NJ, USA). Patients were divided into two groups based on the receptor status of the tumor and were classified either as triple negative, when the tumor lacked progesterone, estrogen and HER-2 receptors, or as receptor-positive when the presence of one or a combination of either three was proven. In the triple-negative tumor group the mean follow up time was 26 months (SD 29) and median follow up time was 16 months. In the receptor-positive tumor group mean follow up was 27 months (SD 24) with a median follow up of 19 months. To assess possible associations between different factors and the outcomes of interest, we used either the chi-square test or Fisher’s exact test for categorical variables and the ANOVA test for continuous variables. For the survival assessment, a Kaplan-Meier analysis was performed and for the cumulative incidence a competing risk analysis was utilized.

Results

The intramedullary rod revision rate for patients in the triple-negative tumor group was 17%, while for the receptor-positive group it was 12%, this was not statistically different for our sample size. The mean time for revision of the intramedullary rod in the whole sample was 19 months (SD 11, range 6–40). The causes of revision were disease progression (43%), nonunion (29%) and surgeon error (29%). The cumulative incidence of revision surgery was 6% (CI 95%, 2–14%) at 12 months and 20% (CI 95%, 8–36%) at 60 months.

Conclusions

Intramedullary rodding can be considered for the treatment of long bones metastases in breast cancer patients for an impending or actual pathological fracture. There is no difference in the intramedullary rod revision rate among patients with different receptor-status when comparing triple-negative tumor patients and receptor-positive ones.

Level of Evidence

Level III, therapeutic study.

Printing the Pathway Forward in Bone Metastatic Cancer Research: Applications of 3D Engineered Models and Bioprinted Scaffolds to Recapitulate the Bone-Tumor Niche

Breast cancer commonly metastasizes to bone, resulting in osteolytic lesions and poor patient quality of life. The bone extracellular matrix (ECM) plays a critical role in cancer cell metastasis by means of the physical and biochemical cues it provides to support cellular crosstalk. Current two-dimensional in-vitro models lack the spatial and biochemical complexities of the native ECM and do not fully recapitulate crosstalk that occurs between the tumor and endogenous stromal cells. Engineered models such as bone-on-a-chip, extramedullary bone, and bioreactors are presently used to model cellular crosstalk and bone-tumor cell interactions, but fall short of providing a bone-biomimetic microenvironment. Three-dimensional bioprinting allows for the deposition of biocompatible materials and living cells in complex architectures, as well as provides a means to better replicate biological tissue niches in-vitro. In cancer research specifically, 3D constructs have been instrumental in seminal work modeling cancer cell dissemination to bone and bone-tumor cell crosstalk in the skeleton. Furthermore, the use of biocompatible materials, such as hydroxyapatite, allows for printing of bone-like microenvironments with the ability to be implanted and studied in in-vivo animal models. Moreover, the use of bioprinted models could drive the development of novel cancer therapies and drug delivery vehicles.

Real-life prognosis of 5041 bone-only metastatic breast cancer patients in the multicenter national observational ESME program

BACKGROUND

Bone-only (BO) metastatic breast cancer (MBC) is considered a more favorable entity than other MBC presentations. However, only few retrospective series and data from selected randomized controlled trials have been reported so far.

METHODS

Using the French national multicenter ESME (Epidemiological Strategy and Medico Economics) Data Platform, the primary objective of our study was to compare the overall survival (OS) of patients with BO versus non-BO MBC at diagnosis, with adjustment on main prognostic factors using a propensity score. Secondary objectives were to compare first-line progression-free survival (PFS1), describe treatment patterns, and estimate factors associated with OS.

RESULTS

Out of 20,095 eligible women, 5041 (22.4%) patients had BO disease [hormone-receptor positive (HR+)/human epidermal growth-factor-receptor-2 negative (HER2-), n = 4 102/13,229 (31%); HER2+, n = 644/3909 (16.5%); HR-/HER2-, n = 295/2 957 (10%)]. BO MBC patients had a better adjusted OS compared with non-BO MBC [52.1 months (95% confidence interval (CI) 50.3-54.1) versus 34.7 months (95% CI 34.0-35.6) respectively]. The 5-year OS rate of BO MBC patients was 43.4% (95% CI 41.7-45.2). They also had a better PFS1 [13.1 months (95% CI 12.6-13.8) versus 8.5 months (95% CI 8.3-8.7), respectively]. This observation could be repeated in all subtypes. BO disease was an independent prognostic factor of OS [hazard ratio 0.68 (95% CI 0.65-0.72), p < 0.0001]. Results were concordant in all analyses.

CONCLUSION

BO MBC patients have better outcomes compared with non-BO MBC, consistently, through all MBC subtypes.

Comparison of the clinicopathological characteristics and prognosis between Chinese patients with breast cancer with bone-only and non-bone-only metastasis

Bone is the most common site of metastatic spread in patients with breast cancer. Patients with bone-only metastasis (BOM) are a unique group. The aim of the present study was to compare the clinicopathological characteristics, survival and prognostic factors of patients with BOM and non-BOM. The clinical data of 1,290 patients with metastatic breast cancer treated at the Tianjin Medical University Cancer Institute and Hospital (Tianjin, China) between January 2008 and December 2017 were reviewed. The clinical data were divided into a BOM group (n=208 cases) and a non-BOM group (n=1,082 cases). Patients with BOM had longer disease-free survival, progression-free survival (PFS) and overall survival (OS) compared with patients in the non-BOM group. The hormone receptor (HR) status and number of metastases were significant influencing factors of PFS in the BOM group. Furthermore, the HR status, location of bone metastasis and number of bone metastases were significantly associated with OS of patients in the BOM group. Age at diagnosis of metastasis, HR status and tumor stage were significantly associated with OS in the non-BOM group. In the BOM group, patients with HR⁺/human epidermal growth factor receptor 2 (HER2)⁻ tumors had the most favorable prognosis. In the non-BOM group, patients with HR⁺/HER2⁻ and HER2⁺ tumors had improved prognosis. In the BOM with HR⁺/HER2⁻ subgroup, the PFS and OS of patients receiving endocrine therapy or sequential therapy (chemotherapy followed by endocrine therapy) was significantly improved compared with those receiving chemotherapy alone (P<0.05). Skeletal-related events were significantly associated with the number of bone metastases (P<0.001). The most common secondary metastatic site in the BOM group was the liver. The prognosis of the patients in the BOM group was improved compared with that in the non-BOM patients. HR⁻ and multiple bone metastases, as well as combined axial and appendicular bone metastases, were significantly associated with poor prognosis in the patients with BOM. For patients in the HR⁺/HER2⁻ BOM subgroup, endocrine therapy alone resulted in satisfactory results.

Diagnostic value of radionuclide in bone metastasis after breast cancer surgery: A protocol of systematic review

BACKGROUND

The objective of this study is to evaluate the accuracy of radionuclide in diagnosis of bone metastasis (BM) after breast cancer surgery (BCS).

METHODS

The electronic databases (Cochrane Library, MEDLINE, EMBASE, Web of Science, CBM, and CNKI) will be systematically and comprehensively searched until June 1, 2020 for eligible studies that reported the diagnosis of radionuclide in BM after BCS. In addition, we will also identify grey literatures, such as conference abstracts, and reference lists of included studies. All process of study identification, data extraction, and study methodological quality evaluation will be performed by 2 independent authors. All divergences will be settled by a third author through discussion. All data analysis will be carried out by RevMan 5.3 software (London, UK).

RESULTS

This study will scrutinize the most recent evidence of radionuclide in detection of BM after BCS.

CONCLUSION

This study may provide evidence of accuracy of radionuclide in diagnosis of BM following BCS.

STUDY REGISTRATION NUMBER

PROSPERO CRD42020187646.

Preclinical study of boron neutron capture therapy for bone metastasis using human breast cancer cell lines

Bone metastasis has a major impact on the quality of life that general therapy cannot control. We established a bone metastasis model with a human breast cancer cell line and investigated the therapeutic effect of boron neutron capture therapy (BNCT). BNCT suppressed tumor growth in cases of intramedullary small tumors without damaging normal tissues, providing preliminary evidence that it is a potentially new therapeutic option for controlling tumor growth from bone metastasis. Further research is warranted for its clinical application.

Combined administration of a small-molecule inhibitor of TRAF6 and Docetaxel reduces breast cancer skeletal metastasis and osteolysis

Tumour necrosis factor receptor-associated factor 6 (TRAF6) has been implicated in breast cancer and osteoclastic bone destruction. Here, we report that 6877002, a verified small-molecule inhibitor of TRAF6, reduced metastasis, osteolysis and osteoclastogenesis in models of osteotropic human and mouse breast cancer. First, we observed that TRAF6 is highly expressed in osteotropic breast cancer cells and its level of expression was higher in patients with bone metastasis. Pre-exposure of osteoclasts and osteoblasts to non-cytotoxic concentrations of 6877002 inhibited cytokine-induced NFκB activation and osteoclastogenesis, and reduced the ability of osteotropic human MDA-MB-231 and mouse 4T1 breast cancer cells to support bone cell activity. 6877002 inhibited human MDA-MB-231-induced osteolysis in the mouse calvaria organ system, and reduced soft tissue and bone metastases in immuno-competent mice following intra-cardiac injection of mouse 4T1-Luc2 cells. Of clinical relevance, combined administration of 6877002 with Docetaxel reduced metastasis and inhibited osteolytic bone damage in mice bearing 4T1-Luc2 cells. Thus, TRAF6 inhibitors such as 6877002 - alone or in combination with conventional chemotherapy - show promise for the treatment of metastatic breast cancer.

Dietary Selenium Supplementation Does Not Attenuate Mammary Tumorigenesis-Mediated Bone Loss in Male MMTV-PyMT Mice

Bone wasting occurs during the progression of breast cancer and contributes to breast cancer mortality. We evaluated the effect of methylseleninic acid (MSeA), an anti-carcinogenic form of selenium, on bone microstructural changes in the presence of mammary tumors in a male breast cancer model of mouse mammary tumor virus-polyomavirus middle T-antigen (MMTV-PyMT). In this study, we performed microcomputed tomographic analysis of femurs and vertebrae collected from a study showing that dietary supplementation with MSeA reduces mammary tumorigenesis in male mice. Compared to age-matched, non-tumor-bearing mice (MMTV-PyMT negative), the presence of mammary tumors significantly reduced the bone volume fraction, trabecular thickness, and bone mineral density while it increased the structure model index in femurs, but not in vertebrae. Moreover, mammary tumorigenesis decreased plasma concentrations of osteocalcin. Supplementation with MSeA did not affect these changes in MMTV-PyMT mice. In conclusion, mammary tumorigenesis caused bone loss in MMTV-PyMT mice. However, dietary supplementation with MSeA did not attenuate mammary tumor-associated bone loss in this model of male breast cancer.

A Deep-Learning Approach for Diagnosis of Metastatic Breast Cancer in Bones from Whole-Body Scans

(1) Background: Bone metastasis is one of the most frequent diseases in breast, lung and prostate cancer; bone scintigraphy is the primary imaging method of screening that offers the highest sensitivity (95%) regarding metastases. To address the considerable problem of bone metastasis diagnosis, focused on breast cancer patients, artificial intelligence methods devoted to deep-learning algorithms for medical image analysis are investigated in this research work; (2) Methods: Deep learning is a powerful algorithm for automatic classification and diagnosis of medical images whereas its implementation is achieved by the use of convolutional neural networks (CNNs). The purpose of this study is to build a robust CNN model that will be able to classify images of whole-body scans in patients suffering from breast cancer, depending on whether or not they are infected by metastasis of breast cancer; (3) Results: A robust CNN architecture is selected based on CNN exploration performance for bone metastasis diagnosis using whole-body scan images, achieving a high classification accuracy of 92.50%. The best-performing CNN method is compared with other popular and well-known CNN architectures for medical imaging like ResNet50, VGG16, MobileNet, and DenseNet, reported in the literature, providing superior classification accuracy; and (4) Conclusions: Prediction results show the efficacy of the proposed deep learning approach in bone metastasis diagnosis for breast cancer patients in nuclear medicine.

Survival in breast cancer patients with spine metastases: Prognostic assessment involving molecular markers

BACKGROUND

To clarify and update the prognostic assessment for heterogeneous population of patients with breast cancer and spine metastases (SpM), using molecular markers.

METHODS

The patient data used in this study was obtained from a French national multi-center database of patients treated for breast cancer with SpM between 2014 and 2017. 556 SpM cases were diagnosed.

RESULTS

Median overall survival (OS) time for all patients following the SpM event was 43.9 months. First, we confirmed 3 previously known significant prognostic factors for survival of patients with SpM: young age [HR: 2.019, 95% CI 1.343-3.037; p = 0.001], good WHO status [ Status 0 HR: 2.823, 95% CI 1.231-3.345; p < 0.0001] or [ Status 1 HR: 1.956, 95% CI 0.768-2.874; p = 0.001] and no-ambulatory neurological status: Frankel A-C [HR: 0.438, 95% CI 0.248-0.772; p = 0.004]. Secondly, we determined the effect of gene mutations on survival in patients with SpM, and we identified that HER2+ cancer subtype [HR: 1.567, 95% CI 0.946-2.557; p = 0.008] was an independent predictor of longer survival, whereas basal cancer subtype [HR: 0.496, 95% CI 0.353-0.699; p < 0.0001] was associated with a poorer prognosis. Other factors including the number of SpM, surgery, extraspinal metastases, synchrone metastases, metastasis-free survival, and SpM recurrence were not identified as prognostically relevant to survival.

CONCLUSION

Survival and our ability to estimate it in breast cancer patients with SpM has improved significantly. Therefore, SpM prognostic scoring algorithms should be updated and incorporate genotypic data on subtypes to make treatment more adaptive.

[Expression of NUF2 in breast cancer and its clinical significance]

OBJECTIVE

To investigate the expression of the cell division- associated gene NUF2 in breast cancer and its clinical significance.

METHODS

The expression of NUF2 in breast cancer tissues was analyzed using Oncomine database. The relationship between the expression of NUF2 and the prognosis of breast cancer was analyzed using the Kaplan-Meier Plotter database. Gene set enrichment analysis (GSEA) and GEO database were used to investigate the effect of NUF2 on gene enrichment. The String database was utilized to analyze the proteins associated with NUF2. The TIMER database was analyzed to assess the correlations of NUF2 with BUB1, MAD2L1 and MYC. The expressions of NUF2 mRNA in 8 pairs of breast cancer tissues and adjacent tissues were verified by q-PCR.

RESULTS

Compared with that in normal breast tissue, NUF2 was significantly overexpressed in breast cancer (P &lt; 0.001). The overall survival time (HR = 1.52, P = 0.015) and the recurrence-free survival time (HR = 1.85, P = 3.2e-14) of the patients with high NUF2 expression were significantly shorter than those of patients with low NUF2 expression. In patients with high NUF2 expression, the enriched genes were involved mainly in cell cycle, P53, G2/M, DNA repair, MYC, and PI3K-AKT-MTOR signaling pathways, which were associated with tumor proliferation, invasion, metastasis and stemness. Combination of the results of String database, gene enrichment and TIMER database analyses suggested that NUF2 interacted directly with BUB1, MAD2L1, and MYC, which could promote the progression of breast cancer. The results of q-PCR showed that NUF2 expression was up-regulated in 6 cancer tissues and down-regulated in 2 cancer tissues.

CONCLUSIONS

NUF2 gene is overexpressed in breast cancer, and its expression level is important in predicting the prognosis of breast cancer.

Development of Zoledronic Acid-Based Nanoassemblies for Bone-Targeted Anticancer Therapy

Bone metastasis occurs in the majority of cancer patients, which hampers quality of life and significantly decreases survival. Aggressive chemotherapy is a traditional treatment regimen that induces severe systemic toxicities. Therefore, bone-directed therapies are highly warranted. We report a novel nanoparticle formulation that is composed of poly(vinylpyrrolidone) and tannic acid core nanoparticles (PVT NPs) that forms self-assembly with zoledronic acid (ZA@PVT NPs). The construction of ZA@PVT NPs was confirmed by particle size, zeta potential, transmission electron microscopy, and spectral analyses. An optimized bone-targeted ZA@PVT NPs formulation showed greater binding and internalization in in vitro with metastasis prostate and breast cancer cells. ZA@PVT NPs were able to deliver ZA more efficiently to tumor cells, which inhibited proliferation of human prostate and breast cancer cells. In addition, ZA@PVT NPs were capable of targeting mouse bones and prostate tumor microarray tissues (ex vivo) while sparing all other vital organs. More importantly, ZA@PVT NPs induce chemo sensitization to docetaxel treatment in cancer cells. Overall, the study results confirm that ZA-based, bone-targeted NPs have great potential for the treatment of bone metastasis in the near future.

Prediction of early metastatic disease in experimental breast cancer bone metastasis by combining PET/CT and MRI parameters to a Model-Averaged Neural Network

Macrometastases in bone are preceded by bone marrow invasion of disseminated tumor cells. This study combined functional imaging parameters from FDG-PET/CT and MRI in a rat model of breast cancer bone metastases to a Model-averaged Neural Network (avNNet) for the detection of early metastatic disease and prediction of future macrometastases. Metastases were induced in 28 rats by injecting MDA-MB-231 breast cancer cells into the right superficial epigastric artery, resulting in the growth of osseous metastases in the right hind leg of the animals. All animals received FDG-PET/CT and MRI at days 0, 10, 20 and 30 after tumor cell injection. In total, 18/28 rats presented with metastases at days 20 or 30 (64.3%). None of the animals featured morphologic bone lesions during imaging at day 10, and the imaging parameters acquired at day 10 did not differ significantly between animals with metastases at or after day 20 and those without (all p > 0.3). The avNNet trained with the imaging parameters acquired at day 10, however, achieved an accuracy of 85.7% (95% CI 67.3-96.0%) in predicting future macrometastatic disease (ROC_AUC 0.90; 95% CI 0.76-1.00), and significantly outperformed the predictive capacities of all single parameters (all p ≤ 0.02). The integration of functional FDG-PET/CT and MRI parameters into an avNNet can thus be used to predict macrometastatic disease with high accuracy, and their combination might serve as a surrogate marker for bone marrow invasion as an early metastatic process that is commonly missed during conventional staging examinations.

Pharmacological inhibition of the IKKε/TBK-1 axis potentiates the anti-tumour and anti-metastatic effects of Docetaxel in mouse models of breast cancer

IκB kinase subunit epsilon (IKKε), a key component of NFκB and interferon signalling, has been identified as a breast cancer oncogene. Here we report that the IKKε/TBK1 axis plays a role in the initiation and progression of breast cancer osteolytic metastasis. Cancer-specific knockdown of IKKε in the human MDA-MB-231-BT cells and treatment with the verified IKKε/TBK1 inhibitor Amlexanox reduced skeletal tumour growth and osteolysis in mice. In addition, combined administration of Amlexanox with Docetaxel reduced mammary tumour growth of syngeneic 4T1 cells, inhibited metastases and improved survival in mice after removal of the primary tumour. Functional and mechanistic studies in breast cancer cells, osteoclasts and osteoblasts revealed that IKKε inhibition reduces the ability of breast cancer cells to grow, move and enhance osteoclastogenesis by engaging both IRF and NFκB signalling pathways. Thus, therapeutic targeting of the IKKε/TBK1 axis may be of value in the treatment of advanced triple negative breast cancer.

Upregulated osterix promotes invasion and bone metastasis and predicts for a poor prognosis in breast cancer

Approximately 70% of patients with advanced breast cancer develop bone metastases, accompanied by complications, such as bone pain, fracture, and hypercalcemia. However, our understanding of the molecular mechanisms that govern this process remains fragmentary. Osterix (Osx) is a zinc finger-containing transcription factor essential for osteoblast differentiation and bone formation. Here, we identified the functional roles of Osx in facilitating breast cancer invasion and bone metastasis. Osx upregulation was associated with lymph node metastasis and was negatively prognostic for overall survival. Knockdown of Osx inhibited invasion of breast cancer and osteolytic metastasis by downregulating MMP9, MMP13, VEGF, IL-8, and PTHrP, which are involved in invasion, angiogenesis, and osteolysis; overexpression of Osx had the opposite effect. Moreover, MMP9 was a direct target of Osx and mediated the Osx-driven invasion of breast cancer cells. Together, our data showed that Osx facilitates bone metastasis of breast cancer by upregulating the expression of a cohort of genes that contribute to steps in the metastatic cascade. These findings suggest that Osx is an attractive target for the control of bone metastasis of breast cancers.

Nuclear Medicine Imaging Techniques for Detection of Skeletal Metastases in Breast Cancer

Bone is the most common site of metastases from advanced breast cancer. Whole-body bone scintigraphy has been most frequently used in the process of managing cancer patients; its advantage is that it provides rapid whole-body imaging for screening of osteoblastic or sclerotic/mixed bone metastases at reasonable cost. Recent advanced techniques, such as single-photon emission computed tomography (SPECT)/CT, quantitative analysis, and bone scan index, contribute to better understanding of the disease state. More recent advances in machines and PET drugs improve the staging of the skeleton with higher sensitivity and specificity.

Dickkopf-1 (Dkk1) protein expression in breast cancer with special reference to bone metastases

Dysregulation of the Wnt inhibitor dickkopf-1 protein (Dkk1) has been reported in a variety of cancers. In addition, it has been linked to the progression of malignant bone disease by impairing osteoblast activity. This study investigated serum- and tissue levels of Dkk1 in breast cancer patients with- or without bone metastases. Serum Dkk1 levels were measured by ELISA in 89 breast cancer patients and 86 healthy women. Tissue levels of Dkk1 and β-catenin, a major downstream component of Wnt transduction pathway, were tested with immunohistochemical staining in 143 different tissues, including adjacent non-tumoral breast tissues, primary breast tumours, lymph nodes metastases, and bone metastases. Serum levels of Dkk1 were significantly increased in breast cancer patients without metastases compared with healthy controls and even more increased in patients with bone metastases. Tissue expression of Dkk1 was positive in 70% of tested primary breast cancer tissues and demonstrated significant correlation with histological type and PR status. Less frequent expression of Dkk1 was found in lymph nodes metastases and bone metastases compared with adjacent non-tumoral breast tissues and primary breast tumours. Tissue expression of β-catenin was positive in the vast majority of all tested tissue types indicating activated Wnt/β-catenin signalling. Our results suggested that Wnt/β-catenin signalling in breast tumours and their secondary lymph nodes- and bone metastases is dysregulated and this could be related to aberrant Dkk1 expression levels. Hence, Dkk1 protein might provide insights into the continued development of novel comprehensive and therapeutic strategies for breast cancer and its bone metastases.

Prognostic Factors in Patients with Metastatic Breast Cancer with Bone-Only Metastases

This article describes the association between pain attributable to bone metastasis and location, as well as number and type of bone metastases at time of bone metastasis diagnosis in metastatic breast cancer patients with bone‐only metastases. The resulting outcomes analysis should allow for earlier interventions or identification for clinical trial involvement.

Background.

Patients with metastatic breast cancer with bone‐only metastases (BOM) are a unique patient population without consensus regarding high‐risk characteristics, which we sought to establish.

Methods.

We identified 1,445 patients with BOM followed for at least 6 months at MD Anderson Cancer Center from January 1, 1997, to December 31, 2015.

Results.

Seventy‐one percent (n = 936) of the 1,325 patients with BOM with available pain characterization were symptomatic at time of BOM diagnosis. Pain was more common in patients with lytic compared with blastic or sclerotic metastases (odds ratio [OR], 1.79; 95% confidence interval [CI,] 1.26–2.53) and multiple versus single bone metastases (OR, 1.37; 95% CI, 1.03–1.83). Poorer overall survival (OS) was also noted in patients with multiple bone metastases (median OS, 4.80 years; 95% CI, 4.49–5.07) compared with single bone metastasis (median OS, 7.54 years; 95% CI, 6.28–10.10) and in patients with metastases in both the axial and appendicular skeleton (median OS, 4.58 years; 95% CI, 4.23–4.96) compared with appendicular‐only (median OS, 6.78 years; 95% CI, 5.26–7.96) or axial‐only metastases (median OS, 5.62 years; 95% CI, 4.81–6.69). Black/non‐Hispanic patients had poorer outcomes, and patients aged 40–49 years at time of breast cancer diagnosis had significantly better OS compared with both younger and older patient groups.

Conclusion.

Overall, several risk features for decreased OS were identified, including multiple bone metastases and both axial and appendicular skeleton involvement. Multiple bone metastases and lytic bone metastases were associated with increased pain.

Implications for Practice.

Patients with metastatic breast cancer and bone‐only metastases (BOM) represent a poorly characterized patient subset. The ability to identify unique patient characteristics at time of BOM diagnosis associated with increased morbidity or mortality would allow for recognition of patients who would benefit from more aggressive therapy. In this study, the largest sample of patients with BOM thus far reported is characterized, highlighting several higher‐risk BOM groups, including those with multiple bone metastases and bone metastases in both the axial and appendicular skeleton at time of BOM diagnosis. In addition to tailoring current practices for these high‐risk patients, ongoing studies of these patients are indicated.

Accuracy of whole-body HDP SPECT/CT, FDG PET/CT, and their combination for detecting bone metastases in breast cancer: an intra-personal comparison

New generation SPECT/CT scanners allow rapid whole-body imaging, and potentially facilitate significantly improved diagnostic accuracy. Thus, the aim of this study was to compare the diagnostic accuracy of whole-body Tc-99m-HDP SPECT/CT, F-18-FDG PET/CT, and their combination for detecting bone metastases in breast cancer. Women with biopsy-proven breast cancer that were referred for whole-body SPECT/CT and FDG PET/CT were consecutively included in this retrospective study. Two blinded readers independently interpreted all scans. In a per-patient analysis, the diagnostic performances of whole-body SPECT/CT, FDG PET/CT, and their combination were compared using receiver operating characteristic (ROC) analysis. In a per-lesion analysis, the performances were compared using figures of merit (FoM) differences in Jackknife alternative free-response ROC analysis, which considers the location information. Follow-up served as reference standard. Overall, 25 consecutive women (median age: 55; range 38-82) with 117 lesions were included. The median follow-up was 21 months (2-46 months). The per-patient analysis revealed no significant differences in diagnostic performance (P = 0.16), while the per-lesion analysis revealed a diagnostic superiority of whole-body SPECT/CT over FDG PET/CT (P = 0.004). Specifically, the PET/CT FoM was significantly lower than the SPECT/CT FoM (FoM difference = -0.11, 95% CI [-0.21; -0.02], P = 0.021). No significant difference was observed between SPECT/CT and the combination of SPECT/CT and PET/CT. The per-lesion analysis suggest that SPECT/CT has a higher diagnostic accuracy than FDG PET/CT for the detection of bone metastases. Thus, SPECT/CT may be a useful adjunct to FDG PET/CT for staging of breast cancer patients.

Cancer Metastases to Bone: Concepts, Mechanisms, and Interactions with Bone Osteoblasts

The skeleton is a unique structure capable of providing support for the body. Bone resorption and deposition are controlled in a tightly regulated balance between osteoblasts and osteoclasts with no net bone gain or loss. However, under conditions of disease, the balance between bone resorption and deposition is upset. Osteoblasts play an important role in bone homeostasis by depositing new bone osteoid into resorption pits. It is becoming increasingly evident that osteoblasts additionally play key roles in cancer cell dissemination to bone and subsequent metastasis. Our laboratory has evidence that when osteoblasts come into contact with disseminated breast cancer cells, the osteoblasts produce factors that initially reduce breast cancer cell proliferation, yet promote cancer cell survival in bone. Other laboratories have demonstrated that osteoblasts both directly and indirectly contribute to dormant cancer cell reactivation in bone. Moreover, we have demonstrated that osteoblasts undergo an inflammatory stress response in late stages of breast cancer, and produce inflammatory cytokines that are maintenance and survival factors for breast cancer cells and osteoclasts. Advances in understanding interactions between osteoblasts, osteoclasts, and bone metastatic cancer cells will aid in controlling and ultimately preventing cancer cell metastasis to bone.

Prospective Study of Serial 18F-FDG PET and 18F-Fluoride PET to Predict Time to Skeletal-Related Events, Time to Progression, and Survival in Patients with Bone-Dominant Metastatic Breast Cancer

Assessing therapy response of breast cancer bone metastases is challenging. In retrospective studies, serial ¹⁸F-FDG PET was predictive of time to skeletal-related events (tSRE) and time to progression (TTP). ¹⁸F-NaF PET improves bone metastasis detection compared with bone scanning. We prospectively tested ¹⁸F-FDG PET and ¹⁸F-NaF PET to predict tSRE, TTP, and overall survival (OS) in patients with bone-dominant metastatic breast cancer (MBC). Methods: Patients with bone-dominant MBC were imaged with ¹⁸F-FDG PET and ¹⁸F-NaF PET before starting new therapy (scan1) and again at a range of times centered around approximately 4 mo later (scan2). Maximum standardized uptake value (SUV_max) and lean body mass adjusted standardized uptake (SUL_peak) were recorded for a single index lesion and up to 5 most dominant lesions for each scan. tSRE, TTP, and OS were assessed exclusive of the PET images. Univariate Cox regression was performed to test the association between clinical endpoints and ¹⁸F-FDG PET and ¹⁸F-NaF PET measures. mPERCIST (Modified PET Response Criteria in Solid Tumors) were also applied. Survival curves for mPERCIST compared response categories of complete response+partial response+stable disease versus progressive disease for tSRE, TTP, and OS. Results: Twenty-eight patients were evaluated. Higher ¹⁸F-FDG SUL_peak at scan2 predicted shorter time to tSRE (P = <0.001) and TTP (P = 0.044). Higher ¹⁸F-FDG SUV_max at scan2 predicted a shorter time to tSRE (P = <0.001). A multivariable model using ¹⁸F-FDG SUV_max of the index lesion at scan1 plus the difference in SUV_max of up to 5 lesions between scans was predictive for tSRE and TTP. Among 24 patients evaluable by ¹⁸F-FDG PET mPERCIST, tSRE and TTP were longer in responders (complete response, partial response, or stable disease) than in nonresponders (progressive disease) (P = 0.007, 0.028, respectively), with a trend toward improved survival (P = 0.1). An increase in the uptake between scans of up to 5 lesions by ¹⁸F-NaF PET was associated with longer OS (P = 0.027). Conclusion: Changes in ¹⁸F-FDG PET parameters during therapy are predictive of tSRE and TTP, but not OS. mPERCIST evaluation in bone lesions may be useful in assessing response to therapy and is worthy of evaluation in multicenter, prospective trials. Serial ¹⁸F-NaF PET was associated with OS but was not useful for predicting TTP or tSRE in bone-dominant MBC.

Interleukin-6 receptor inhibitor suppresses bone metastases in a breast cancer cell line

BACKGROUND

Interleukin-6 (IL-6) is a potent inflammatory cytokine that appears to play a key role in cancer growth and metastasis. In the present study, the effects of IL-6 receptor (IL-6R) on breast cancer aggressiveness and bone metastases were investigated.

METHODS

MDA-MB-231 (MDA-231) cells were treated in the presence or absence of anti-human IL-6 receptor (IL-6R) monoclonal antibody and examined with respect to cell survival. The expressions of signal transducer and activator of transcription 3 (Stat3), vascular endothelial growth factor (VEGF), and receptor activator of NF-κB (RANK) were analyzed by SDS-PAGE and immunoblotting. MDA-231 cells were injected into the left ventricle of mice, and then anti-human IL-6R monoclonal antibody or saline was administered intraperitoneally for 28 days. After 28 days, the incidence of bone metastases was evaluated in the hind limbs by radiography and histology.

RESULTS

Anti-human IL-6R monoclonal antibody reduced bone metastases in an animal model injected with MDA-231 cells on radiological and histomorphometric analyses. The mechanism of bone metastasis inhibition involved inhibited cell proliferation and decreased expressions of phospho-Stat3, VEGF, and RANK in MDA-231 cells.

CONCLUSIONS

The results of the present study suggest that inhibition of IL-6 signaling may become a preventive therapeutic option for breast cancer and bone metastases.

TGF-α Overexpression in Breast Cancer Bone Metastasis and Primary Lesions and TGF-α Enhancement of Expression of Procancer Metastasis Cytokines in Bone Marrow Mesenchymal Stem Cells

Bone metastasis (BM) is the advanced complication of breast cancer, while bone marrow-derived mesenchymal stem cells (BMSCs) in the microenvironment unclearly contribute to cancer metastasis. This study investigated potential roles of transforming growth factor- (TGF-) α in the interaction between breast cancer and BMSCs in BM. Clinical cases of breast cancer with bone metastasis (BMBC), breast cancer without bone metastasis (Non-BM-BC), and benign fibroadenoma (Benign) were enlisted in a retrospective study. TGF-α was found obviously overexpressed in BM lesion of BMBC compared to primary lesion of both BMBC and Non-BM-BC (P < 0.01), and TGF-α was higher in primary lesion of both BMBC and Non-BM-BC (P < 0.01) than Benign group. Interestingly, TGF-α in nontumor tissues of both BMBC and Non-BM-BC was at a higher level than Benign group (P < 0.01), and numbers of macrophages in nontumor tissues of both BMBC and Non-BM-BC (P < 0.01) were higher than Benign group. Furthermore, in cultured human BMSCs, TGF-α stimulated production of procancer cytokines including IL-6, VEGF, FGF10, FGF17, and TGF-β1 in a dose-dependent manner. Thus, TGF-α in BC could potentially be an important signal of carcinogenesis and metastasis. Macrophages in the nontumor tissue of BC may not be protective but could promote cancer metastasis.

Incidence, risk factors and prognostic characteristics of bone metastases and skeletal-related events (SREs) in breast cancer patients: A systematic review of the real world data

Purpose

The aim was to systematically extrapolate the occurrence, risk factors, prognostic characteristics, management and outcome of bone metastases (BM) and skeletal related events (SREs) of breast cancer survivors in the real world clinical setting.

Methods

A systematic literature search of PubMed, Web of Science, EMBASE OvidSP and EBSCO Academic Search Complete was conducted. Published prospective and retrospective papers investigating BM and SREs in breast cancer patients in non-trial settings were identified and systematically reviewed.

Results

Twenty-four studies met the inclusion criteria. Incidences of BM based on new diagnosis, length of BM-free interval (BMFI) and number and sites of BM were detected by 17 of 24 studies. Seven studies included in the review were subjected to analyses of risk factors for BM. Developments of SREs regarding the occurrence ratio of total and specific SREs, SERs-free interval (SREFI) and the first-line therapy for SREs were observed in 16 of 24 studies. Out of 5 studies, we extracted uni- and multivariate analysis of risk factor for SREs and out of 16 studies - predictors for survival in breast cancer patients with BM.

Conclusions

BM and SREs are common problems in non-trial breast cancer populations. Patient demographics, clinical stage, tumor pathological type, molecular receptors status are significantly risk factors for incidence of BM, SREs and the survival. The unique characteristics of BM and SREs in breast cancer patients should be taken into account in future randomized controlled trials, as to optimize individual treatment options and assure a maximally long good quality of life.