Clinical outcome of brain metastases differs significantly among breast cancer subtypes

Targeting HMGA1 contributes to immunotherapy in aggressive breast cancer while suppressing EMT

Metastasis is an obstacle to the clinical treatment of aggressive breast cancer (BC). Studies have shown that high mobility group A1 (HMGA1) is abnormally expressed in various cancers and mediates tumor proliferation and metastasis. Here, we provided more evidence that HMGA1 mediated epithelial to mesenchymal transition (EMT) through the Wnt/β-catenin pathway in aggressive BC. More importantly, HMGA1 knockdown enhanced antitumor immunity and improved the response to immune checkpoint blockade (ICB) therapy by upregulating programmed cell death ligand 1 (PD-L1) expression. Simultaneously, we revealed a novel mechanism by which HMGA1 and PD-L1 were regulated by the PD-L1/HMGA1/Wnt/β-catenin negative feedback loop in aggressive BC. Taken together, we believe that HMGA1 can serve as a target for the dual role of anti-metastasis and enhancing immunotherapeutic responses.

The role of the NDRG1 in the pathogenesis and treatment of breast cancer

Breast cancer (BC) is the leading cause of cancer death in women. This disease is heterogeneous, with clinical subtypes being estrogen receptor-α (ER-α) positive, having human epidermal growth factor receptor 2 (HER2) overexpression, or being triple-negative for ER-α, progesterone receptor, and HER2 (TNBC). The ER-α positive and HER2 overexpressing tumors can be treated with agents targeting these proteins, including tamoxifen and pertuzumab, respectively. Despite these treatments, resistance and metastasis are problematic, while TNBC is challenging to treat due to the lack of suitable targets. Many studies examining BC and other tumors indicate a role for N-myc downstream-regulated gene-1 (NDRG1) as a metastasis suppressor. The ability of NDRG1 to inhibit metastasis is due, in part, to the inhibition of the initial step in metastasis, namely the epithelial-to-mesenchymal transition. Paradoxically, there are also reports of NDRG1 playing a pro-oncogenic role in BC pathogenesis. The oncogenic effects of NDRG1 in BC have been reported to relate to lipid metabolism or the mTOR signaling pathway. The molecular mechanism(s) of how NDRG1 regulates the activity of multiple signaling pathways remains unclear. Therapeutic strategies that up-regulate NDRG1 have been developed and include agents of the di-2-pyridylketone thiosemicarbazone class. These compounds target oncogenic drivers in BC cells, suppressing the expression of multiple key hormone receptors including ER-α, progesterone receptor, androgen receptor, and prolactin receptor, and can also overcome tamoxifen resistance. Considering the varying role of NDRG1 in BC pathogenesis, further studies are required to examine what subset of BC patients would benefit from pharmacopeia that up-regulate NDRG1.

Anti-Hormonal Therapy in Breast Cancer and Its Effect on the Blood-Brain Barrier

The molecular receptor status of breast cancer has implications for prognosis and long-term metastasis. Although metastatic luminal B-like, hormone-receptor-positive, HER2−negative, breast cancer causes brain metastases less frequently than other subtypes, though tumor metastases in the brain are increasingly being detected of this patient group. Despite the many years of tried and tested use of a wide variety of anti-hormonal therapeutic agents, there is insufficient data on their intracerebral effectiveness and their ability to cross the blood-brain barrier. In this review, we therefore summarize the current state of knowledge on anti-hormonal therapy and its intracerebral impact and effects on the blood-brain barrier in breast cancer.

CSCO expert consensus on the diagnosis and treatment of breast cancer brain metastasis

Breast cancer is one of the most common malignancies among women worldwide. According to the International Agency for Research on Cancer, breast cancer affected more Chinese women than any other cancer in 2020. The brain is an increasingly common metastatic sites of breast cancer. Although the risk of developing brain metastases (BMs) is lower in breast cancer than in lung cancer and melanoma, due to its high prevalence, it is the second most common cause of BM among solid tumors, being second only to lung cancer. The incidence of breast cancer brain metastasis (BCBM) differs by molecular subtype. Half of patients with advanced human epidermal growth factor receptor-2 (HER2)-positive and one-third of patients with triple-negative breast cancer (TNBC) develop BM. The clinical manifestations of leptomeningeal metastasis (LM) are often non-specific and may manifest as a variety of signs and symptoms, mainly including brain parenchyma involvement and meningeal irritation syndromes cranial nerve involvement, increased intracranial pressure, and progressive brain dysfunction. Therefore, the Chinese Society of Clinical Oncology (CSCO) Breast Cancer Committee has developed this expert consensus on BM, in an effort to improve the overall prognosis of BCBM and promote the standardized diagnosis and treatment of this disease. During the development of this expert consensus, we carried out a comprehensive literature review and referred to some of the most authoritative guidelines in China and abroad. In this consensus, we will discuss clinical manifestations, imaging examinations, pathological diagnosis, treatments, prognosis, follow-up and monitoring. We hope this consensus will be of help to all the clinicians majored in breast cancer and other similar professions.

Real-world outcomes among patients with HER2+ metastatic breast cancer with brain metastases

BACKGROUND: Among patients with human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer (MBC), incidence of brain metastases (BMs) is relatively high and increasing. Despite the high unmet need for patients with HER2+ MBC and BMs, real-world data on treatment patterns and outcomes for these patients are limited. OBJECTIVE: To compare treatment patterns and overall survival (OS) among patients with HER2+ MBC with and without BMs in the United States. METHODS: This was a real-world retrospective cohort study in which adults diagnosed with HER2+ MBC between January 1, 2016, and May 31, 2019, were identified in the Flatiron Health electronic health records database. The cohort was stratified by presence of BMs at MBC diagnosis (baseline) and before the initiation of each line of therapy (LOT). Key outcomes were OS and systemic therapy/regimen used within each LOT. An adjusted Cox proportional hazards model was used to evaluate the impact of BMs on OS. RESULTS: Of 1,755 included patients, 173 (9.9%) had BMs at baseline. Trastuzumab+ pertuzumab-based regimens were the most common first- (n = 689, 44.3%) and second-line (n = 316, 35.3%) treatments for all patients. Among patients with BMs, trastuzumab emtansine was the most common third-line regimen (n = 18, 23.4%). Lapatinib-based regimens were used more frequently among patients with BMs but were used by less than 20% of patients with BMs within any LOT. Median OS was 22.3 and 37.3 months for patients with and without BMs at baseline, respectively. Patients with BMs had a higher risk of death compared with patients without BMs (HR, 3.2; 95% CI = 2.6-3.8). CONCLUSIONS: BMs are associated with an increased risk of mortality among patients with HER2+ MBC. Further studies are needed to evaluate the extent to which novel systemic therapies for HER2+ MBC address the unmet need among patients with BMs. DISCLOSURES: This study was funded by Seagen Inc. Andres Forero-Torres is an employee of and owns stock in Seagen Inc. Kendra DeBusk is an employee of Seagen Inc. and owns stock in Seagen Inc. and Roche. Andy Surinach and Yutong Liu are employees of Genesis Research, which received funding from Seagen Inc. in connection with this study. At the time of this study, Chimeka Ike was an employee of Seagen Inc. and owns stock in Seagen Inc. At the time of this study, Nicolas Lindegger was an employee of Seagen Inc., Seagen International GmbH, and owns stock in Seagen Inc. and Roche. At the time of this study, Naomi Schwartz was a paid consultant to Seagen Inc.; she currently is an employee of and owns stock in Seagen Inc.

NDRG1 in Aggressive Breast Cancer Progression and Brain Metastasis

BACKGROUND

N-Myc downstream regulated gene 1 (NDRG1) suppresses metastasis in many human malignancies, including breast cancer, yet has been associated with worse survival in patients with inflammatory breast cancer. The role of NDRG1 in the pathobiology of aggressive breast cancers remains elusive.

METHODS

To study the role of NDRG1 in tumor growth and brain metastasis in vivo, we transplanted cells into cleared mammary fat pads or injected them in tail veins of SCID/Beige mice (n = 7-10 per group). NDRG1 protein expression in patient breast tumors (n = 216) was assessed by immunohistochemical staining. Kaplan-Meier method with 2-sided log-rank test was used to analyze the associations between NDRG1 and time-to-event outcomes. A multivariable Cox regression model was used to determine independent prognostic factors. All statistical tests were 2-sided.

RESULTS

We generated new sublines that exhibited a distinct propensity to metastasize to the brain. NDRG1-high-expressing cells produced more prevalent brain metastases (100% vs 44.4% for NDRG1-low sublines, P = .01, Fisher's exact test), greater tumor burden, and reduced survival in mice. In aggressive breast cancer cell lines, silencing NDRG1 led to reduced migration, invasion, and tumor-initiating cell subpopulations. In xenograft models, depleting NDRG1 inhibited primary tumor growth and brain metastasis. In patient breast tumors, NDRG1 was associated with aggressiveness: NDRG1-high expression was also associated with shorter overall survival (hazard ratio [HR] = 2.27, 95% confidence interval [95% CI] = 1.20 to 4.29, P = .009) and breast cancer-specific survival (HR = 2.19, 95% CI = 1.07 to 4.48, P = .03). Multivariable analysis showed NDRG1 to be an independent predictor of overall survival (HR = 2.17, 95% CI = 1.10 to 4.30, P = .03) and breast cancer-specific survival rates (HR = 2.27, 95% CI = 1.05 to 4.92, P = .04).

CONCLUSIONS

We demonstrated that NDRG1 drives tumor progression and brain metastasis in aggressive breast cancers and that NDRG1-high expression correlates with worse clinical outcomes, suggesting that NDRG1 may serve as a therapeutic target and prognostic biomarker in aggressive breast cancers.

Anti-EGFR VHH-armed death receptor ligand-engineered allogeneic stem cells have therapeutic efficacy in diverse brain metastatic breast cancers

Basal-like breast cancer (BLBC) shows brain metastatic (BM) capability and overexpresses EGFR and death-receptors 4/5 (DR4/5); however, the anatomical location of BM prohibits efficient drug-delivery to these targetable markers. In this study, we developed BLBC-BM mouse models featuring different patterns of BMs and explored the versatility of estem cell (SC)-mediated bi-functional EGFR and DR4/5-targeted treatment in these models. Most BLBC lines demonstrated a high sensitivity to EGFR and DR4/5 bi-targeting therapeutic protein, E_VDR_L [anti-EGFR VHH (E_V) fused to DR ligand (DR_L)]. Functional analyses using inhibitors and CRISPR-Cas9 knockouts revealed that the E_V domain facilitated in augmenting DR4/5-DR_L binding and enhancing DR_L-induced apoptosis. E_VDR_L secreting stem cells alleviated tumor-burden and significantly increased survival in mouse models of residual-tumor after macrometastasis resection, perivascular niche micrometastasis, and leptomeningeal metastasis. This study reports mechanism based simultaneous targeting of EGFR and DR4/5 in BLBC and defines a new treatment paradigm for treatment of BM.

"Triple-Negative Breast Cancer Central Nervous System Metastases From the Laboratory to the Clinic"

ABSTRACT

Triple-negative breast cancer (TNBC) accounts for 15% to 20% of breast cancers and has an incidence as high as 50% of brain metastases once patients develop advanced disease. The lack of targeted and effective therapies, characteristic of this subtype of breast cancer, is especially evident once central nervous system (CNS) metastases occur. Compared with other subtypes of breast cancer, TNBC patients have the shorter interval from diagnosis to development of brain metastases and the shorter overall survival once they occur, a median of 4 to 6 months. Preclinical studies of TNBC and CNS microenvironment are actively ongoing, clarifying mechanisms and orienting more effective approaches to therapy. While the first drugs have been specifically approved for use in metastatic TNBC, data on their CNS effect are still awaited.

The current status of cancer survivorship care and a consideration of appropriate care model in Korea

Purpose

Breast cancer patients with a human epidermal growth factor receptor 2 (HER2) enriched subtype are known to have higher rates of brain metastases (BM) than other patients. This study aimed to evaluate treatment options and survival outcomes.

Methods

A total of 115 breast cancer brain metastases (BCBM) patients with nearly complete medical records were retrospectively analyzed. Additionally, 36 patients were HER2 enriched types according to histological subtypes. The BM was found by brain magnetic resonance imaging in patients who had neurologic symptoms or by regular screening. Age, breast tumor size, number of BM, histological subtypes, first treatment of breast cancer, estrogen receptor, and HER2 status, stage, local treatment of BM were analyzed. Median overall survival, 5-year survival were analyzed from the data.

Results

The median survival time after BM was 6 months, the mean survival time was 16.3 months, and the 5-year survival after BM was only 8.0%. Factors that significantly affect the survival of BCBM patients include histological subtype, number of BM, use of lapatinib in multivariate analysis. A total of 19 out of 36 HER2 enriched patients were treated with lapatinib or capecitabine. For the treatment of HER2 enriched patients, additional use of blood-brain barrier (BBB) crossing substances, as well as local treatment for BM, significantly improve the survival rate in the Kaplan-Meier method (P=0.001).

Conclusion

A combination of local treatment modality for BCBM and the use of substances that cross the BBB for the HER2 enriched patient improved the survival rate.

Brain metastases from breast cancer

BACKGROUND

Breast cancer (BC) is one of the commonest causes of brain metastases (BM): approximately 10-16 % of patients diagnosed with metastatic breast cancer will eventually develop BM during the course of their disease, however, certain subtypes have a higher risk of this event. The aim of this analysis was therefore to evaluate the prognosis and the pattern and imaging features of BM according to different BC subtypes.

PATIENTS AND METHODS

We retrospectively reviewed the case records of patients with breast cancer and evidence of brain metastases from the database of IPO Porto between 2014-2018. The data obtained were statistically analysed.

RESULTS

We analysed 147 patients with BM from BC. The triple-negative subtype had the shortest overall survival (OS) after BM, besides a short period of time between BC and BM. HER2 overexpressing tumors had the longest OS. The estrogen-receptor positive group had the greatest interval between initial BC diagnosis and diagnosis of BM. Larger lesions showed a heterogeneous contrast enhancement and were heterogeneous pn T2WI sequences; a hyposignal on T2*WI was also associated with larger lesions. Triple-negative BC tended to have more heterogeneous lesions on T1WI. We noticed that the hippocampus is rarely affected by metastatic lesions.

CONCLUSIONS

Based on the BC subtype it is possible to make a prediction about the prognosis of the disease and some imaging features of the BM, but not about their pattern of distribution. These data support further research concerning prevention, early detection, and treatment of BM from BC.

Heterogeneity and vascular permeability of breast cancer brain metastases

Improvements in the diagnosis and treatment of systemic breast cancer have led to a prolongation in patient survival. Unfortunately, these advances are also associated with an increased incidence of brain metastases (BM), with the result that many patients succumb due to BM treatment failure. Intracranial delivery of many chemotherapeutic agents and other therapeutics is hindered by the presence of an impermeable blood-brain barrier (BBB) designed to protect the brain from harmful substances. The formation of BM compromises the integrity of the BBB, resulting in a highly heterogeneous blood-tumor barrier (BTB) with varying degrees of vascular permeability. Here, we discuss how blood vessels play an important role in the formation of brain micrometastases as well as in the transformation from poorly permeable BM to highly permeable BM. We then review the role of BTB vascular permeability in the diagnostics and the choice of treatment regimens for breast cancer brain metastases (BCBM) and discuss whether the vasculature of primary breast cancers can serve as a biomarker for BM. Specifically, we examine the association between the vascular permeability of BCBM and their accumulation of large molecules such as antibodies, which remains largely unexplored.

Identification of ALDH1A3 as a Viable Therapeutic Target in Breast Cancer Metastasis-Initiating Cells

The development of efficacious therapies targeting metastatic spread of breast cancer to the brain represents an unmet clinical need. Accordingly, an improved understanding of the molecular underpinnings of central nervous system spread and progression of breast cancer brain metastases (BCBM) is required. In this study, the clinical burden of disease in BCBM was investigated, as well as the role of aldehyde dehydrogenase 1A3 (ALDH1A3) in the metastatic cascade leading to BCBM development. Initial analysis of clinical survival trends for breast cancer and BCBM determined improvement of breast cancer survival rates; however, this has failed to positively affect the prognostic milestones of triple-negative breast cancer (TNBC) brain metastases (BM). ALDH1A3 and a representative epithelial-mesenchymal transition (EMT) gene signature (mesenchymal markers, CD44 or Vimentin) were compared in tumors derived from BM, lung metastases (LM), or bone metastases (BoM) of patients as well as mice after injection of TNBC cells. Selective elevation of the EMT signature and ALDH1A3 were observed in BM, unlike LM and BoM, especially in the tumor edge. Furthermore, ALDH1A3 was determined to play a role in BCBM establishment via regulation of circulating tumor cell adhesion and migration phases in the BCBM cascade. Validation through genetic and pharmacologic inhibition of ALDH1A3 via lentiviral shRNA knockdown and a novel small-molecule inhibitor demonstrated selective inhibition of BCBM formation with prolonged survival of tumor-bearing mice. Given the survival benefits via targeting ALDH1A3, it may prove an effective therapeutic strategy for BCBM prevention and/or treatment.

Nanoparticles Containing a Combination of a Drug and an Antibody for the Treatment of Breast Cancer Brain Metastases

In women with human epidermal growth factor 2 (HER2)-positive breast cancer, the improved control of systemic disease with new therapies has unmasked brain metastases that historically would have remained clinically silent. The efficacy of therapeutic agents against brain metastases is limited by their inability to permeate the blood-brain and blood-tumor barriers (BBB and BTB) in therapeutic amounts. Here, we investigate the potential of mucic acid-based, targeted nanoparticles designed to transcytose the BBB/BTB to deliver a small molecule drug, camptothecin (CPT), and therapeutic antibody, Herceptin, to brain metastases in mice. Treatment with BBB-targeted combination CPT/Herceptin nanoparticles significantly inhibits tumor growth compared to free CPT/Herceptin and BBB-targeted nanoparticles carrying CPT alone. Though not as efficacious, BBB-targeted nanoparticles carrying only Herceptin also elicit considerable antitumor activity. These results demonstrate the potential of the targeted nanoparticle system for the delivery of an antibody alone or in combination with other drugs across the BBB/BTB to improve the therapeutic outcome.

Treatment and outcomes in patients with central nervous system metastases from breast cancer in the real-life ESME MBC cohort

AIM

The aims of the present study were to describe treatment patterns and survival outcomes in patients with central nervous system metastases (CNSM) selected among metastatic breast cancer (MBC) patients included in a retrospective study from the Epidemiological Strategy and Medical Economics (ESME) MBC cohort.

METHODS

Neurological progression-free survival (NPFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Significant contributors to NPFS were determined using a multivariate Cox proportional hazards model.

RESULTS

After a median follow-up of 42.8 months, of 16 701 patients included in the ESME MBC database, CNSM were diagnosed in 24.6% of patients. The most frequent treatments after diagnosis of CNSM were whole-brain radiotherapy (WBRT) (45.2%) and systemic treatment (59.3%). Median OS and NPFS were 7.9 months (95% CI: 7.2-8.4) and 5.5 months (95% CI: 5.2-5.8), respectively. In multivariate analysis, age >70 years (vs <50 years; HR = 1.40; 95% CI: 1.24-1.57), triple-negative tumours (vs HER2-/HR+; HR = 1.87; 95% CI: 1.71-2.06), HER2+/HR-tumours (vs HER2-/HR+; HR = 1.14; 95% CI: 1.02-1.27), ≥3 metastatic sites (vs < 3; HR = 1.32; 95% CI: 1.21-1.43) and ≥3 previous treatment lines (vs < 3; HR = 1.75; 95% CI: 1.56-1.96) were detrimental for NPFS. A time interval between selection and CNSM diagnosis superior to 18 months (vs <9 months; HR = 0.88; 95% CI: 0.78-0.98) was associated with longer NPFS.

CONCLUSIONS

This study describes current treatment patterns of MBC patients in a "real life" setting. Despite advances in stereotactic radiation therapy, most of the patients still received WBRT. More research is warranted to identify patient subsets for tailored treatment strategies.

Impact of breast cancer cells´ secretome on the brain metastatic niche remodeling

Brain metastases occur in approximately 10-20% of patients with metastatic breast cancer showing a very poor overall survival. Curiously, different molecular subtypes (that show specific gene expression signatures and differential prognostic significance) are associated with different risks for brain metastases development, suggesting that cancer cells harbor specific molecular programs that award them intrinsic advantages to survive in this specific foreign tissue. Emerging data has been revealing that biophysical and/or mechanical properties of the brain extracellular matrix (ECM), along with those of the brain resident cells, play a crucial role in creating the best conditions for survival, colonization and outgrowth of breast cancer cells in this distinct microenvironment. Although several reports show that cancer cells modulate metastatic niches way before they reach the target organ, few data exist for the brain metastatic niche. Indeed, little is known concerning how factors secreted by cancer cells activate brain resident cells and/or modify brain ECM biomechanical properties and how these modifications impact cells´ ability to metastasize the brain. The brain is a particular organ, protected by the blood brain barrier (BBB), and containing exclusive functional units and very special cell types. Additionally, it is the organ with the most singular ECM and biomechanical properties. Thus, this cancer cell-brain metastatic niche interaction must present distinct properties. Consequently, the search for putative molecular markers that modulate the brain pre-metastatic niche, thus promoting the successful metastatic homing of cancer cells, is urgently needed. In this review, we will discuss key aspects regarding breast cancer cells and the brain pre-metastatic niche paracrine communication that is crucial to initiate the metastatic cascade. We will focus on cancer cell`s secretome influence into the brain microenvironment, specifically on its impact on tissue mechanics and on brain resident cells as regulators of the pre-metastatic niche formation, ultimately promoting metastatic colonization.

Neoadjuvant neratinib promotes ferroptosis and inhibits brain metastasis in a novel syngeneic model of spontaneous HER2+ve breast cancer metastasis

Background

Human epidermal growth factor receptor-2 (HER2)-targeted therapies prolong survival in HER2-positive breast cancer patients. Benefit stems primarily from improved control of systemic disease, but up to 50% of patients progress to incurable brain metastases due to acquired resistance and/or limited permeability of inhibitors across the blood-brain barrier. Neratinib, a potent irreversible pan-tyrosine kinase inhibitor, prolongs disease-free survival in the extended adjuvant setting, and several trials evaluating its efficacy alone or combination with other inhibitors in early and advanced HER2-positive breast cancer patients are ongoing. However, its efficacy as a first-line therapy against HER2-positive breast cancer brain metastasis has not been fully explored, in part due to the lack of relevant pre-clinical models that faithfully recapitulate this disease. Here, we describe the development and characterisation of a novel syngeneic model of spontaneous HER2-positive breast cancer brain metastasis (TBCP-1) and its use to evaluate the efficacy and mechanism of action of neratinib.

Methods

TBCP-1 cells were derived from a spontaneous BALB/C mouse mammary tumour and characterised for hormone receptors and HER2 expression by flow cytometry, immunoblotting and immunohistochemistry. Neratinib was evaluated in vitro and in vivo in the metastatic and neoadjuvant setting. Its mechanism of action was examined by transcriptomic profiling, function inhibition assays and immunoblotting.

Results

TBCP-1 cells naturally express high levels of HER2 but lack expression of hormone receptors. TBCP-1 tumours maintain a HER2-positive phenotype in vivo and give rise to a high incidence of spontaneous and experimental metastases in the brain and other organs. Cell proliferation/viability in vitro is inhibited by neratinib and by other HER2 inhibitors, but not by anti-oestrogens, indicating phenotypic and functional similarities to human HER2-positive breast cancer. Mechanistically, neratinib promotes a non-apoptotic form of cell death termed ferroptosis. Importantly, metastasis assays demonstrate that neratinib potently inhibits tumour growth and metastasis, including to the brain, and prolongs survival, particularly when used as a neoadjuvant therapy.

Conclusions

The TBCP-1 model recapitulates the spontaneous spread of HER2-positive breast cancer to the brain seen in patients and provides a unique tool to identify novel therapeutics and biomarkers. Neratinib-induced ferroptosis provides new opportunities for therapeutic intervention. Further evaluation of neratinib neoadjuvant therapy is warranted.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1177-1) contains supplementary material, which is available to authorized users.

Characterization of molecular scores and gene expression signatures in primary breast cancer, local recurrences and brain metastases

Background

Breast cancer is a leading cause of cancer-related death in women worldwide. Despite extensive studies in all areas of basic, clinical and applied research, accurate prognosis remains elusive, thus leading to overtreatment of many patients. Diagnosis could be improved by introducing multigene molecular scores in standard clinical practice. Several tests that work with formalin-fixed tissue have become routine. Molecular scores usually include several genes representing processes, response to oestrogens, progestogens and human epidermal growth factor receptor 2 (Her2), respectively, which are combined additively in single values. These multi-gene scores have the advantage of being more robust and reproducible than single-gene scores. Their utility may be further enhanced by combining them with classical diagnostic parameters. Here, we present an exploratory study comparing the RISK and research versions of Oncotype DX recurrence score (RS), Prosigna Risk of Recurrence (ROR) and EndoPredict (EP) with respect to their prognostic potential for ipsilateral recurrence and/or distant relapse in brain, and we compared the scores to the intrinsic subtypes based on PAM50.

Methods

RNA was extracted from formalin-fixed, paraffin-embedded (FFPE) tissue cores of primary tumours, local recurrences and brain metastases. Gene expression was measured on a NanoString nCounter Analysis System. Intrinsic subtypes and molecular scores were computed according to published literature and RISK, RS, ROR and EP were compared against each other and to the intrinsic subtypes Luminal A (lumA), Luminal B (lumB), Her2-enriched (Her2↑), Basal-like (basal), and Normal-like (normal) of PAM50. Local recurrences and brain metastases were compared to their corresponding primary tumours.

Results

All four molecular scores were highly correlated. Highest correlations were observed among genes related to proliferation while lower correlations were found among oestrogen-related genes. The scores were significantly higher in primary tumours progressing to brain metastases as compared to recurrence-free primary tumours and primary tumours that relapsed as local recurrences.

Conclusions

RISK and ROR-P are prognostic for primary tumours metastasizing to the brain. All four scores, RISK, RS, EP and ROR-P failed to discriminate between primary tumours that remained recurrence-free and primary tumours relapsing as local recurrences.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5752-8) contains supplementary material, which is available to authorized users.

Exosomes: A Promising Avenue for the Diagnosis of Breast Cancer

Currently, despite the advances in individualized treatment, breast cancer still remains the deadliest form of cancer in women. Diagnostic, prognostic, and therapy-predictive methods are mainly based on the evaluation of tumor tissue samples and are aimed to improve the overall therapeutic level. Therefore, the exploration of a series of circulating biomarkers, which serve as the information source of tumors and could be obtained by peripheral blood samples, represents a high field of interest. Apart from classical biomarkers, exosomes, which are nanovesicles, are emerging as an accessible and efficient source of cell information. The purpose of this review is to summarize the peculiarities of the presently available breast cancer exosomal biomarkers; the review also provides the prediction of a multitude of potential target genes of exosomal microRNAs using 4 databases.

Investigational chemotherapy and novel pharmacokinetic mechanisms for the treatment of breast cancer brain metastases

In women, breast cancer is the most common cancer diagnosis and second most common cause of cancer death. More than half of breast cancer patients will develop metastases to the bone, liver, lung, or brain. Breast cancer brain metastases (BCBM) confers a poor prognosis, as current therapeutic options of surgery, radiation, and chemotherapy rarely significantly extend life and are considered palliative. Within the realm of chemotherapy, the last decade has seen an explosion of novel chemotherapeutics involving targeting agents and unique dosage forms. We provide a historical overview of BCBM chemotherapy, review the mechanisms of new agents such as poly-ADP ribose polymerase inhibitors, cyclin-dependent kinase 4/6 inhibitors, phosphatidyl inositol 3-kinaseinhibitors, estrogen pathway antagonists for hormone-receptor positive BCBM; tyrosine kinase inhibitors, antibodies, and conjugates for HER2+ BCBM; repurposed cytotoxic chemotherapy for triple negative BCBM; and the utilization of these new agents and formulations in ongoing clinical trials. The mechanisms of novel dosage formulations such as nanoparticles, liposomes, pegylation, the concepts of enhanced permeation and retention, and drugs utilizing these concepts involved in clinical trials are also discussed. These new treatments provide a promising outlook in the treatment of BCBM.

Hormone receptors status: a strong determinant of the kinetics of brain metastases occurrence compared with HER2 status in breast cancer

Breast cancer (BC) metastatic behavior varies according to the hormone receptors (HR) and HER2 statuses. Indeed, patients with triple-negative (TN) and HER2+ tumors are at higher risk of brain metastases (BM). The objective of this multinational cohort was to evaluate BM kinetics depending on the BC subtype. We retrospectively analyzed a series of BC patients with BM diagnosed in four European institutions (1996-2016). The delay between BC and BM diagnoses (BM-free survival) according to tumor biology was estimated with the Kaplan-Meier method. A multivariate analysis was performed using the Cox proportional hazards regression model. 649 women were included: 32.0% HER2-/HR+, 24.8% TN, 22.2% HER2+/HR- and 21.0% HER2+/HR+ tumors. Median age at BM diagnosis was 56 (25-85). In univariate analysis, BM-free survival differed depending on tumor biology: HER2-/HR+ 5.3 years (95% CI 4.6-5.9), HER2+/HR+ 4.4 years (95% CI 3.4-5.2), HER2+/HR- 2.6 years (95% CI 2.2-3.1) and TN 2.2 years (95% CI 1.9-2.7) (p < 0.001). It was significantly different between HR+ and HR- tumors (5.0 vs. 2.5 years, p < 0.001), and between HER2+ and HER2- tumors (3.2 vs. 3.8 years, p = 0.039). In multivariate analysis, estrogen-receptors (ER) and progesterone-receptors (PR) negativity, but not HER2 status, were independently associated with BM-free survival (hazard ratio = 1.36 for ER, p = 0.013, 1.31 for PR, p = 0.021, and 1.01 for HER2+ vs. HER2- tumors, p = 0.880). HR- and HER2+ tumors are overrepresented in BC patients with BM, supporting a higher risk of BM in these biological subtypes. HR status, but not HER2 status, impacts the kinetics of BM occurrence.

External validation of Modified Breast Graded Prognostic Assessment for breast cancer patients with brain metastases: A multicentric European experience

BACKGROUND

Several prognostic scores have been developed to estimate survival of breast cancer (BC) patients with brain metastases (BM). Modified Breast Graded Prognostic Assessment (GPA), based on a single-institution cohort of 1552 patients, has been proposed as refinement of Breast-GPA. In addition to age, tumour subtype and KPS, Modified Breast-GPA comprises number of BM. This study was designed to validate Modified Breast-GPA.

PATIENTS AND METHODS

Clinical data of 668 BC patients diagnosed with BM at four institutions between 1996 and 2016 were reviewed. Patients were classified by Breast-GPA and Modified Breast-GPA. Overall survival (OS) was calculated from time of BM diagnosis to death or last follow-up. Cox proportional models were used to calculate hazard-ratios and their 95% CI. The performances of Breast-GPA and Modified Breast-GPA were compared using Harrell's concordance index.

RESULTS

Median age at BM diagnosis was 56 years (range 24-85). At last follow-up, 632 patients (94.6%) had died. Median OS was 8.1 months (95% CI 6.9-9.4). The number of BM (1-3 vs. >3) was significantly associated with OS in univariate analysis (p < 0.001) and having >3 BM was identified as a negative prognostic factor in multivariate analysis. Both Breast-GPA and Modified Breast-GPA accurately predicted OS (p < 0.001 for both scores). Performance of Modified Breast-GPA was better: concordance indices were 0.6390 (95% CI, 0.6381 to 0.6399) and 0.6647 (95% CI, 0.6639 to 0.6655) for Breast-GPA and Modified Breast-GPA, respectively (p < 0.001).

CONCLUSIONS

This work provides the first external independent validation of Modified Breast-GPA and confirms its better performance as compared to Breast-GPA.