Breast carcinoma subtypes show different patterns of metastatic behavior

Endophytic fungi: A future prospect for breast cancer therapeutics and drug development

Globally, breast cancer is a primary contributor to cancer-related fatalities and illnesses among women. Consequently, there is a pressing need for safe and effective treatments for breast cancer. Bioactive compounds from endophytic fungi that live in symbiosis with medicinal plants have garnered significant interest in pharmaceutical research due to their extensive chemical composition and prospective medicinal attributes. This review underscores the potentiality of fungal endophytes as a promising resource for the development of innovative anticancer agents specifically tailored for breast cancer therapy. The diversity of endophytic fungi residing in medicinal plants, success stories of key endophytic bioactive metabolites tested against breast cancer and the current progress with regards to in vivo studies and clinical trials on endophytic fungal metabolites in breast cancer research forms the underlying theme of this article. A thorough compilation of putative anticancer compounds sourced from endophytic fungi that have demonstrated therapeutic potential against breast cancer, spanning the period from 1990 to 2022, has been presented. This review article also outlines the latest trends in endophyte-based drug discovery, including the use of artificial intelligence, machine learning, multi-omics approaches, and high-throughput strategies. The challenges and future prospects associated with fungal endophytes as substitutive sources for developing anticancer drugs targeting breast cancer are also being highlighted.

Disrupting EGFR-HER2 Transactivation by Pertuzumab in HER2-Positive Cancer: Quantitative Analysis Reveals EGFR Signal Input as Potential Predictor of Therapeutic Outcome

Pertuzumab (Perjeta®), a humanized antibody binding to the dimerization arm of HER2 (Human epidermal growth factor receptor-2), has failed as a monotherapy agent in HER2 overexpressing malignancies. Since the molecular interaction of HER2 with ligand-bound EGFR (epidermal growth factor receptor) has been implied in mitogenic signaling and malignant proliferation, we hypothesized that this interaction, rather than HER2 expression and oligomerization alone, could be a potential molecular target and predictor of the efficacy of pertuzumab treatment. Therefore, we investigated static and dynamic interactions between HER2 and EGFR molecules upon EGF stimulus in the presence and absence of pertuzumab in HER2+ EGFR+ SK-BR-3 breast tumor cells using Förster resonance energy transfer (FRET) microscopy and fluorescence correlation and cross-correlation spectroscopy (FCS/FCCS). The consequential activation of signaling and changes in cell proliferation were measured by Western blotting and MTT assay. The autocorrelation functions of HER2 diffusion were best fitted by a three-component model corrected for triplet formation, and among these components the slowly diffusing membrane component revealed aggregation induced by EGFR ligand binding, as evidenced by photon-counting histograms and co-diffusing fractions. This aggregation has efficiently been prevented by pertuzumab treatment, which also inhibited the post-stimulus interaction of EGFR and HER2, as monitored by changes in FRET efficiency. Overall, the data demonstrated that pertuzumab, by hindering post-stimulus interaction between EGFR and HER2, inhibits EGFR-evoked HER2 aggregation and phosphorylation and leads to a dose-dependent decrease in cell proliferation, particularly when higher amounts of EGF are present. Consequently, we propose that EGFR expression on HER2-positive tumors could be taken into consideration as a potential biomarker when predicting the outcome of pertuzumab treatment.

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.

Exploration of anatomical distribution of brain metastasis from breast cancer at first diagnosis assisted by artificial intelligence

Objectives

This study aimed to explore the spatial distribution of brain metastases (BMs) from breast cancer (BC) and to identify the high-risk sub-structures in BMs that are involved at first diagnosis.

Methods

Magnetic resonance imaging (MRI) scans were retrospectively reviewed at our centre. The brain was divided into eight regions according to its anatomy and function, and the volume of each region was calculated. The identification and volume calculation of metastatic brain lesions were accomplished using an automatically segmented 3D BUC-Net model. The observed and expected rates of BMs were compared using 2-tailed proportional hypothesis testing.

Results

A total of 250 patients with BC who presented with 1694 BMs were retrospectively identified. The overall observed incidences of the substructures were as follows: cerebellum, 42.1 %; frontal lobe, 20.1 %; occipital lobe, 9.7 %; temporal lobe, 8.0 %; parietal lobe, 13.1 %; thalamus, 4.7 %; brainstem, 0.9 %; and hippocampus, 1.3 %. Compared with the expected rate based on the volume of different brain regions, the cerebellum, occipital lobe, and thalamus were identified as higher risk regions for BMs (P value ≤ 5.6*10-3). Sub-group analysis according to the type of BC indicated that patients with triple-negative BC had a high risk of involvement of the hippocampus and brainstem.

Conclusions

Among patients with BC, the cerebellum, occipital lobe and thalamus were identified as higher-risk regions than expected for BMs. The brainstem and hippocampus were high-risk areas of the BMs in triple negative breast cancer. However, further validation of this conclusion requires a larger sample size.

Imaging features of breast cancer subtypes on contrast enhanced ultrasound: a feasibility study

The objective of this research was to study the contrast enhancement patterns of the different molecular subtypes of breast cancer on contrast-enhanced ultrasound (CEUS) using both qualitative and quantitative parameters. This prospective study included females with a single breast mass which was histopathologically proven carcinoma. B mode ultrasound (USG) and CEUS were performed in all patients during baseline assessment. Qualitative CEUS assessment encompassed enhancement pattern, presence of fill-in and washout. Quantitative assessment included measurement of peak enhancement, time to peak; area under the curve and mean transit time. A p-value < 0.05 was considered statistically significant for differentiating the subtypes. The included thirty masses were categorised into two subtypes-triple negative breast cancer (TNBC) (36.7%) and non-TNBC (63.3%) subtypes. With B-mode USG, a statistically significant difference was observed between the two groups with respect to their shape and margins. TNBC lesions showed an oval shape, circumscribed margins and peripheral nodular enhancement on CEUS with the absence of fill-in even in the delayed phase (p-value - 0.04). The two subtypes did not significantly differ in terms of quantitative perfusion parameters. The various subtypes of breast cancer therefore possess distinct contrast enhancement patterns. CEUS potentially allows differentiation amongst these molecular subtypes that may aid in radiology-pathology (rad-path) correlation and follow up of the patients.

Construction of ceRNA prognostic model based on the CCR7/CCL19 chemokine axis as a biomarker in breast cancer

BACKGROUND

The study of CCR7/CCL19 chemokine axis and breast cancer (BC) prognosis and metastasis is a current hot topic. We constructed a ceRNA network and risk-prognosis model based on CCR7/CCL19.

METHODS

Based on the lncRNA, miRNA and mRNA expression data downloaded from the TCGA database, we used the starbase website to find the lncRNA and miRNA of CCR7/CCL19 and established the ceRNA network. The 1008 BC samples containing survival data were divided into Train group (504 cases) and Test group (504 cases) using R "caret" package. Then we constructed a prognostic risk model using RNA screened by univariate Cox analysis in the Train group and validated it in the Test and All groups. In addition, we explored the correlation between riskScores and clinical trials and immune-related factors (22 immune-infiltrating cells, tumor microenvironment, 13 immune-related pathways and 24 HLA genes). After transfection with knockdown CCR7, we observed the activity and migration ability of MDA-MB-231 and MCF-7 cells using CCK8, scratch assays and angiogenesis assays. Finally, qPCR was used to detect the expression levels of five RNAs in the prognostic risk model in MDA-MB-231 and MCF-7 cell.

RESULTS

Patients with high expression of CCR7 and CCL19 had significantly higher overall survival times than those with low expression. The ceRNA network is constructed by 3 pairs of mRNA-miRNA pairs and 8 pairs of miRNA-lncRNA. After multivariate Cox analysis, we obtained a risk prognostic model: riskScore= -1.544 *`TRG-AS1`+ 0.936 * AC010327.5 + 0.553 *CCR7 -0.208 *CCL19 -0.315 *`hsa-let-7b-5p. Age, stage and riskScore can all be used as independent risk factors for BC prognosis. By drug sensitivity analysis, we found 5 drugs targeting CCR7 (convolamine, amikacin, AH-23,848, ondansetron, flucloxacillin). After transfection with knockdown CCR7, we found a significant reduction in cell activity and migration capacity in MDA-MB-231 cells.

CONCLUSION

We constructed the first prognostic model based on the CCR7/CCL19 chemokine axis in BC and explored its role in immune infiltration, tumor microenvironment, and HLA genes.

Mechanistic elucidation of Juglanthraquinone C targeting breast Cancer: A network Pharmacology-based investigation

Breast cancer is the leading cause of death among women worldwide. Despite the recent treatment options like surgery, chemotherapy etc. the lethality of breast cancer is alarming. Natural compounds are considered a better treatment option against breast carcinoma because of their lower side effects and specificity in targeting important proteins involved in the aberrant activation of pathways in breast cancer. A recently discovered compound called Juglanthraquinone C, which is found in the bark of the Juglans mandshurica Maxim (Juglandaceae) tree has shown promising cytotoxicity in hepatocellular carcinoma. However, not much data is available on the molecular mechanisms followed by this compound. Therefore, we aimed to investigate the molecular mechanism followed by Juglanthraquinone C against breast cancer. We used the network pharmacology technique to analyse the mechanism of action of Juglanthraquinone C in breast cancer and validated our study by applying various computational tools such as UALCAN, cBioportal, TIMER, docking and simulation. The results showed the compound and breast cancer target network shared 31 common targets. Moreover, we observed that Juglanthraquinone C targets multiple deregulated genes in breast cancer such as TP53, TGIF1, IGF1R, SMAD3, JUN, CDC42, HBEGF, FOS and signaling pathways such as PI3K-Akt pathway, TGF-β signaling pathway, MAPK pathway and HIPPO signaling pathway. A docking examination revealed that the investigated drug had a high affinity for the primary target TGIF1 protein. A stable protein-ligand combination was generated by the best hit molecule, according to molecular dynamics modeling. The main aim of this study was to examine Juglanthraquinone C's significance as a prospective breast cancer treatment and to better understand the molecular mechanism this substance uses in breast cancer since there is a need to discover new therapeutics to decrease the load on current therapeutics which also are currently ineffective due to several side effects and development of drug resistance.

A Tumor Microenvironment-Driven Network Regulated by STAT3 and p65 Negatively Controls the Enrichment of Cancer Stem Cells in Human HR+/HER2- Breast Cancer

Hormone receptor-positive and HER2-negative (HR+/HER2-; luminal A) tumors are prevalent in breast cancer. Our past studies demonstrated that "TME Stimulation" (estrogen + TNFα + EGF, representing three arms of the tumor microenvironment, TME) has enriched metastasis-forming cancer stem cells (CSCs) in HR+/HER2- human breast cancer cells. Here, following information obtained by RNAseq analyses of TME-stimulated CSCs and Non-CSCs, we found that TME Stimulation has induced the activation of S727-STAT3, Y705-STAT3, STAT1 and p65. Upon TME Stimulation, stattic (STAT3 inhibitor) usage demonstrated that Y705-STAT3 activation negatively controlled CSC enrichment and epithelial-to-mesenchymal transition (EMT) traits, while inducing CXCL8 (IL-8) and PD-L1 expression. However, STAT3 knock-down (siSTAT3) had no effect on these functions; in terms of CSC enrichment, p65 had down-regulatory roles that compensated for the loss of an entire STAT3 protein. Y705-STAT3 and p65 acted additively in reducing CSC enrichment, and Y705A-STAT3 variant + sip65 has enriched chemo-resistant CSCs. Clinical data analyses revealed an inverse correlation between Y705-STAT3 + p65 phosphorylation and CSC signature in luminal A patients, and connection to improved disease course. Overall, we find regulatory roles for Y705-STAT3 and p65 in TME-stimulated HR+/HER2- tumors, with the ability to limit CSC enrichment. These findings raise concerns about using inhibitors of STAT3 and p65 as therapeutic strategies in the clinic.

PD-1/PD-L1 blockade inhibits epithelial-mesenchymal transition and improves chemotherapeutic response in breast cancer

Therapies targeting the PD-1/PD-L1 axis have recently been implemented for triple negative breast cancer (TNBC) management with limited efficacy, indicating that this axis may promote tumor growth by means other than immune suppression. Because PD-L1 overexpression causes resistance to the chemotherapeutic response in many cancers, here we explored the tumor promoting role of the PD-1/PD-L1 axis in breast cancer. We observed that the downregulation of PD-L1 by specific siRNA and pharmacological inhibitor significantly suppressed tumor cell proliferation, invasion and migration thereby enhancing T cell-mediated cell killing in vitro. We also showed that inhibiting PD-L1 improves cytotoxic sensitivity to chemotherapy in TNBC cells. Our in vivo results confirmed that combining a PD-L1 inhibitor with chemotherapy could significantly reduce tumor progression by inhibiting epithelial-mesenchymal transition. Overall, our results proved that PD-L1 contributes to the transformation and progression of breast cancer cells and that its intervention is a promising therapeutic strategy against breast cancer.

The Role of Autophagy in Breast Cancer Metastasis

Patient morbidity and mortality is significantly increased in metastatic breast cancer. The metastasis process of breast cancer is very complicated and is delicately controlled by various factors. Autophagy is one of the important regulatory factors affecting metastasis in breast cancer by engaging in cell mobility, metabolic adaptation, tumor dormancy, and cancer stem cells. Here, we discuss the effects of autophagy on metastasis in breast cancer and assess the potential use of autophagy modulators for metastasis treatment.

Molecular subtypes predict the preferential site of distant metastasis in advanced breast cancer: a nationwide retrospective study

Objective

This study aimed to explore possible associations between molecular subtypes and site of distant metastasis in advanced breast cancer (ABC).

Methods

3577 ABC patients were selected from 21 hospitals of seven geographic regions in China from 2012-2014. A questionnaire was designed to collect medical information regarding demographic characteristics, risk factors, molecular subtype, recurrence/metastasis information, and disease-free survival (DFS). The cancers were classified into Luminal A, Luminal B, HER2-enriched and Triple Negative subtypes. Chi-square test and multivariate Cox proportional hazard models were performed to explore the associations between molecular subtypes and distant metastasis sites.

Results

A total of 2393 cases with molecular subtypes information were finally examined. Patients with Luminal A (51.1%) and Luminal B (44.7%) were most prone to bone metastasis, whereas liver metastasis was more frequently observed in HER2-enriched ABC patients (29.1%).The cumulative recurrence and metastasis rates of ABC patients at 36 months of DFS were the most significant within molecular types, of which Triple Negative was the highest (82.7%), while that of Luminal A was the lowest (58.4%). In the adjusted Cox regression analysis, Luminal B, HER2-enriched and Triple Negative subtypes increased the risk of visceral metastasis by 23%, 46% and 87% respectively. In addition, Triple Negative patients had a higher probability of brain metastasis (HR 3.07, 95% CI: 1.04-9.07).

Conclusion

Molecular subtypes can predict the preferential sites of distant metastasis, emphasizing that these associations were of great help in choices for surveillance, developing appropriate screening and cancer management strategies for follow-up and personalized therapy in ABC patients.

Evaluation of breast cancer metastasis and mortality rates based on molecular subtype: A description study

BACKGROUND

Breast cancer in Indonesia has continued to increase. One diagnostic modality is immunohistochemical examination to determine breast cancer subtypes.

OBJECTIVE

To determine breast cancer metastasis and mortality rates based on molecular subtypes.

METHODS

A descriptive study was conducted based on retrospective data from hospital medical records from January 2016 to December 2019. The data comprised age, clinical stage, histopathological grade, molecular subtype, location, metastasis, and breast cancer mortality. The data were processed and analyzed.

RESULTS

This study involved 172 patients. The most prevalent breast cancer subtypes were luminal A (60, 34.8%), followed by HER2 (47, 27.4%), triple-negative (38, 22.4%), and luminal B (27, 15.4%). The metastasis rate was 37.21% (64/172), with bone the tissue most affected (32 cases, 50%), followed by lung (24 cases, 37.5%) and liver (8 cases, 12.5%). The highest rates of bone, lung, and liver metastases were subtypes luminal A (31%), HER2 (29%), and triple-negative (38%), respectively. The mortality rate was 21% (36/172), with most in the triple-negative group (28.9%), followed by luminal B (25.9%), HER2 (21.2%), and luminal A (13.3%).

CONCLUSIONS

Determination of breast cancer molecular subtypes through immunohistochemistry can determine the level of metastasis and mortality in breast cancer.

Web-Based Dynamic Nomograms for Predicting Overall Survival and Cancer-Specific Survival in Breast Cancer Patients with Lung Metastases

BACKGROUND

60-70% of patients who die from breast cancer have lung metastases. However, there is a lack of readily available tools for accurate risk stratification in patients with breast cancer lung metastases (BCLM). Therefore, a web-based dynamic nomogram was developed for BCLM to quickly, accurately, and intuitively assess overall and cancer-specific survival rates.

METHODS

Patients diagnosed with BCLM between 2004 and 2016 were extracted from the Surveillance, Epidemiology, and Final Results (SEER) database. After excluding incomplete data, all patients were randomly assigned to training and validation cohorts (2:1). Patients' basic clinical information, detailed pathological staging and treatment information, and sociological information were included in further analysis. Nomograms were constructed following the evaluations of the Cox regression model and verified using the concordance index (C-index), calibration curves, time-dependent receiver operating characteristic (ROC) curves, and decision curve analysis (DCA). Web-based dynamic nomograms were published online.

RESULTS

3916 breast cancer patients with lung metastases were identified from the SEER database. Based on multivariate Cox regression analysis, overall survival (OS) and cancer-specific survival (CSS) are significantly correlated with 13 variables: age, marital status, race, grade, T stage, surgery, chemotherapy, bone metastatic, brain metastatic, liver metastatic, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2). These are included in the construction of the nomogram of OS and CSS. The time-dependent receiver operating characteristic curve, decision curve analysis, consistency index, and calibration curve prove the distinct advantages of the nomogram.

CONCLUSIONS

Our web-based dynamic nomogram effectively integrates patient molecular subtype and sociodemographic characteristics with clinical characteristics and guidance and can be easily used. ER-Negative should receive attention in diagnosing and treating BCLM.

A pilot study: Comparison of TRPS1 and GATA3 immunoperoxidase staining using cytologic smears in entities reportedly positive for GATA3

BACKGROUND

Metastatic breast carcinoma (mBC) is frequently encountered and may be challenging to diagnose as the tumor cells can morphologically resemble carcinomas of other primary origins. An additional challenge is that direct smears are often the only sample type available for immunostaining studies in cytology. Trichorhinophalangeal syndrome GATA-binding type 1 1 (TRPS1) is a highly sensitive marker for BC compared to the commonly used marker GATA3, especially in triple-negative BC (TNBC), in histologic samples. However, its sensitivity and specificity in mBC and other GATA3-positive tumors have not been studied.

METHODS

The authors identified the following cytology cases: 37 GATA3-positive mBC cases and 19 available cases that were deemed mBC but were GATA3-negative during the original case workup and five cases of each of eight epithelioid entities known to have high rates of GATA3 positivity and commonly seen in cytology practice. Immunostainings of TRPS1 and GATA3 were performed on the chosen smears following standard protocols.

RESULTS

TRPS1 was positive in all 37 GATA3-positive mBC cases and in 18 of the 19 GATA3-negative mBC cases. TRPS1 was negative in all five of the seven frequently GATA3-positive epithelioid entities, with the exception of salivary duct carcinomas where GATA3 was positive in a rate ranging 60%-100% among them.

CONCLUSIONS

TRPS1 is as sensitive as GATA3 in GATA3-positive mBC and is more sensitive than GATA3 in TNBC. TRPS1 is negative in most GATA3-positive nonbreast tumors. Thus, the combination of TRPS1 and GATA3 could be used to differentiate breast primary from others in most situations.

Prominin 1 Significantly Correlated with Bone Metastasis of Breast Cancer and Influenced the Patient’s Prognosis

Background

This study is aimed at identifying the important biomarkers associated with bone metastasis (BM) in breast cancer (BRCA).

Methods

The GSE175692 dataset was used to detect significant differential expressed genes (DEGs) between BRCA samples with or without BM, and DEG-related pathways were then explored. Further, we constructed the protein-protein interaction (PPI) network on GEGs and filtered 5 vital nodes. We then performed the Cox regression, Kaplan-Meier analysis, nomogram, and ROC curve to filter the most significant prognosis genes. The GSE14020 and GSE124647 datasets were used to verify the expression and prognostic value of hub genes, respectively. Finally, the gene set enrichment analysis (GSEA) was performed to reveal the potential mechanism.

Results

Totally, 74 DEGs were detected, which mainly correlated with infectious disease, signaling molecules, and interaction. The 5 important DEGs were then filtered, and the Cox regression further showed that 2 genes, including prominin 1 (PROM1) and C-C motif chemokine ligand 2 (CCL2), were related to the prognosis of BRCA metastasis patients. Especially, PROM1 presented a better prognostic performance on the survival probability of patients than CCL2. Verification analysis further confirmed the abnormal expression and significant prognostic influence of PROM1. Finally, GSEA revealed that PROM1 was negatively related to IGF1 and mTOR pathways in BRCA metastasis.

Conclusion

PROM1 was an important biomarker associated with BRCA bone metastasis and affected the prognosis of metastatic BRCA patients. It may play a vital role in metastatic BRCA by negatively regulating IGF1 and mTOR pathways.

PAK-dependent regulation of actin dynamics in breast cancer cells

Metastatic Breast Cancer has a poor 25% survival rate and currently there are no clinical therapeutics which target metastasis. 'Migrastatics' are a new drug class which target migration pathway effector proteins in order to inhibit cancer cell invasion and metastasis. The p21-activated kinases (PAKs) are essential drivers of breast cancer cell migration and invasion through their regulation of actin cytoskeletal dynamics. Therefore, the PAKs present as attractive migrastatic candidates. Here we review how PAKs regulate distinct aspects of breast cancer actin dynamics focussing on cytoskeletal reorganisation, cell:matrix adhesion, actomyosin contractility and degradative invasion. Lastly, we discuss the introduction of PAK migrastatics into the well-honed breast cancer clinical pipeline.

Global Increase in Breast Cancer Incidence: Risk Factors and Preventive Measures

Breast cancer is a global cause for concern owing to its high incidence around the world. The alarming increase in breast cancer cases emphasizes the management of disease at multiple levels. The management should start from the beginning that includes stringent cancer screening or cancer registry to effective diagnostic and treatment strategies. Breast cancer is highly heterogeneous at morphology as well as molecular levels and needs different therapeutic regimens based on the molecular subtype. Breast cancer patients with respective subtype have different clinical outcome prognoses. Breast cancer heterogeneity emphasizes the advanced molecular testing that will help on-time diagnosis and improved survival. Emerging fields such as liquid biopsy and artificial intelligence would help to under the complexity of breast cancer disease and decide the therapeutic regimen that helps in breast cancer management. In this review, we have discussed various risk factors and advanced technology available for breast cancer diagnosis to combat the worst breast cancer status and areas that need to be focused for the better management of breast cancer.

Tumor Cell-Autonomous Pro-Metastatic Activities of PD-L1 in Human Breast Cancer Are Mediated by PD-L1-S283 and Chemokine Axes

Simple Summary

Triple-negative breast cancer (TNBC) is an aggressive disease that responds in a limited manner to immune checkpoint blockades targeting the PD-L1/PD-1 axis, suggesting that PD-L1 potentiates TNBC progression via pathways not related to immune suppression. We demonstrated that, in human breast cancer cells, PD-L1 expression increased in a cell-autonomous manner tumor cell growth, invasion and release of pro-metastatic factors; these activities were elevated by exposure to PD-1 and were markedly impaired in S283-mutated PD-L1-expressing cells. Invasion of WT-PD-L1-expressing TNBC cells depended on autocrine chemokine circuits, involving CXCR1/2, CCR2, CCR5 and their ligands. In T cell-deficient mice, WT-PD-L1 exhibited increased tumor growth and metastasis by TNBC cells, whereas S283A-PD-L1-expressing cells showed a very poor tumorigenic and metastatic profile. These findings on cell-autonomous and PD-1-induced pro-metastatic activities of PD-L1 in cancer cells suggest that treatments targeting PD-L1 could improve the efficacy of immune-targeting checkpoint inhibitors, e.g., anti-PD-1 or anti-CTLA-4 in TNBC.

Abstract

Therapies targeting the PD-L1/PD-1 axis have recently been introduced to triple-negative breast cancer (TNBC) with limited efficacy, suggesting that this axis promotes tumor progression through mechanisms other than immune suppression. Here, we over-expressed WT-PD-L1 in human TNBC cells (express endogenous PD-L1) and in luminal-A breast cancer cells (no endogenous PD-L1 expression) and demonstrated that cell-autonomous PD-L1 activities lead to increased tumor cell growth, invasion and release of pro-metastatic factors (CXCL8, sICAM-1, GM-CSF). These activities were promoted by PD-1 and were inhibited by mutating S283 in PD-L1. Invasion of WT-PD-L1-cells required signaling by chemokine receptors CXCR1/2, CCR2 and CCR5 through autocrine circuits involving CXCL8, CCL2 and CCL5. Studies with T cell-deficient mice demonstrated that cell-autonomous WT-PD-L1 activities in TNBC cells increased tumor growth and metastasis compared to knock-out (KO)-PD-L1-cells, whereas S283A-PD-L1-expressing cells had minimal ability to form tumors and did not metastasize. Overall, our findings reveal autonomous and PD-1-induced tumor-promoting activities of PD-L1 that depend on S283 and on chemokine circuits. These results suggest that TNBC patients whose tumors express PD-L1 could benefit from therapies that prevent immune suppression by targeting PD-1/CTLA-4, alongside with antibodies to PD-L1, which would allow maximal impact by mainly targeting the cancer cells.

Bone Metastatic Breast Cancer: Advances in Cell Signaling and Autophagy Related Mechanisms

Bone metastasis is a frequent complication of breast cancer with nearly 70% of metastatic breast cancer patients developing bone metastasis during the course of their disease. The bone represents a dynamic microenvironment which provides a fertile soil for disseminated tumor cells, however, the mechanisms which regulate the interactions between a metastatic tumor and the bone microenvironment remain poorly understood. Recent studies indicate that during the metastatic process a bidirectional relationship between metastatic tumor cells and the bone microenvironment begins to develop. Metastatic cells display aberrant expression of genes typically reserved for skeletal development and alter the activity of resident cells within the bone microenvironment to promote tumor development, resulting in the severe bone loss. While transcriptional regulation of the metastatic process has been well established, recent findings from our and other research groups highlight the role of the autophagy and secretory pathways in interactions between resident and tumor cells during bone metastatic tumor growth. These reports show high levels of autophagy-related markers, regulatory factors of the autophagy pathway, and autophagy-mediated secretion of matrix metalloproteinases (MMP's), receptor activator of nuclear factor kappa B ligand (RANKL), parathyroid hormone related protein (PTHrP), as well as WNT5A in bone metastatic breast cancer cells. In this review, we discuss the recently elucidated mechanisms and their crosstalk with signaling pathways, and potential therapeutic targets for bone metastatic disease.

Advances in radiotherapy in bone metastases in the context of new target therapies and ablative alternatives: A critical review

In patients with bone metastases (BM), radiotherapy (RT) is used to alleviate symptoms, reduce the risk of fracture, and improve quality of life (QoL). However, with the emergence of concepts like oligometastases, minimal invasive surgery, ablative therapies such as stereotactic ablative RT (SABR), radiosurgery (SRS), thermal ablation, and new systemic anticancer therapies, there have been a paradigm shift in the multidisciplinary approach to BM with the aim of preserving mobility and function survival. Despite guidelines on using single-dose RT in uncomplicated BM, its use remains relatively low. In uncomplicated BM, single-fraction RT produces similar overall and complete response rates to RT with multiple fractions, although it is associated with a higher retreatment rate of 20% versus 8%. Complicated BM can be characterised as the presence of impending or existing pathologic fracture, a major soft tissue component, existing spinal cord or cauda equina compression and neuropathic pain. The rate of complicated BM is around 35%. Unfortunately, there is a lack of prospective trials on RT in complicated BM and the best dose/fractionation regimen is not yet established. There are contradictory outcomes in studies reporting BM pain control rates and time to pain reduction when comparing SABR with Conventional RT. While some studies showed that SABR produces a faster reduction in pain and higher pain control rates than conventional RT, other studies did not show differences. Moreover, the local control rate for BM treated with SABR is higher than 80% in most studies, and the rate of grade 3 or 4 toxicity is very low. The use of SABR may be preferred in three circumstances: reirradiation, oligometastatic disease, and radioresistant tumours. Local ablative therapies like SABR can delay change or use of systemic therapy, preserve patients' Qol, and improve disease-free survival, progression-free survival and overall survival. Moreover, despite the potential benefit of SABR in oligometastatic disease, there is a need to establish the optial indication, RT dose fractionation, prognostic factors and optimal timing in combination with systemic therapies for SABR. This review evaluates the role of RT in BM considering these recent treatment advances. We consider the definition of complicated BM, use of single and multiple fractions RT for both complicated and uncomplicated BM, reirradiation, new treatment paradigms including local ablative treatments, oligometastatic disease, systemic therapy, physical activity and rehabilitation.

Endogenous and Therapeutic Estrogens: Maestro Conductors of the Microenvironment of ER+ Breast Cancers

Estrogen receptor alpha (ERα) marks heterogeneous breast cancers which display a repertoire of somatic genomic mutations and an immune environment that differs from other breast cancer subtypes. These cancers also exhibit distinct biological behaviors; despite an overall better prognosis than HER2+ or triple negative breast cancers, disseminated dormant cells can lead to disease recurrence decades after the initial diagnosis and treatment. Estrogen is the best studied driver of these cancers, and antagonism or reduction of estrogen activity is the cornerstone of therapeutic approaches. In addition to reducing proliferation of ERα+ cancer cells, these treatments also alter signals to multiple other target cells in the environment, including immune cell subpopulations, cancer-associated fibroblasts, and endothelial cells via several distinct estrogen receptors. In this review, we update progress in our understanding of the stromal cells populating the microenvironments of primary and metastatic ER+ tumors, the effects of estrogen on tumor and stromal cells to modulate immune activity and the extracellular matrix, and net outcomes in experimental and clinical studies. We highlight new approaches that will illuminate the unique biology of these cancers, provide the foundation for developing new treatment and prevention strategies, and reduce mortality of this disease.

Continuous Inflammatory Stimulation Leads via Metabolic Plasticity to a Prometastatic Phenotype in Triple-Negative Breast Cancer Cells

Chronic inflammation promotes cancer progression by affecting the tumor cells and their microenvironment. Here, we demonstrate that a continuous stimulation (~6 weeks) of triple-negative breast tumor cells (TNBC) by the proinflammatory cytokines tumor necrosis factor α (TNFα) + interleukin 1β (IL-1β) changed the expression of hundreds of genes, skewing the cells towards a proinflammatory phenotype. While not affecting stemness, the continuous TNFα + IL-1β stimulation has increased tumor cell dispersion and has induced a hybrid metabolic phenotype in TNBC cells; this phenotype was indicated by a transcription-independent elevation in glycolytic activity and by increased mitochondrial respiratory potential (OXPHOS) of TNBC cells, accompanied by elevated transcription of mitochondria-encoded OXPHOS genes and of active mitochondria area. The continuous TNFα + IL-1β stimulation has promoted in a glycolysis-dependent manner the activation of p65 (NF-κB), and the transcription and protein expression of the prometastatic and proinflammatory mediators sICAM-1, CCL2, CXCL8 and CXCL1. Moreover, when TNBC cells were stimulated continuously by TNFα + IL-1β in the presence of a glycolysis inhibitor, their conditioned media had reduced ability to recruit monocytes and neutrophils in vivo. Such inflammation-induced metabolic plasticity, which promotes prometastatic cascades in TNBC, may have important clinical implications in treatment of TNBC patients.

Risk Factors and Survival of Patients With Liver Metastases at Initial Metastatic Breast Cancer Diagnosis in Han Population

The risk factors for morbidity and mortality in patients with breast cancer liver metastases (BCLM) upon initial metastatic breast cancer (MBC) diagnosis have not been adequately identified in Han population. Data of 3,161 female patients who were initially diagnosed with MBC from December 1991 to September 2019 and treated in the China National Cancer Center were extracted and a total of 2,263 MBC patients were included in our study, among which 550 patients had liver metastases. Multivariable logistic regression was performed to identify risk factors for the presence of liver metastases at initial MBC diagnosis. Univariable and multivariable Cox proportional hazards regression analyses were conducted to determine prognostic factors for the survival of BCLM patients. Patients with hormone receptor (HR)-negative, human epidermal growth factor receptor 2 (HER2)-positive (35.0% of the entire population) subtype had the highest incidence of liver metastases. De novo stage IV breast cancer, HR−/HER2+ and HR+/HER2+ subtypes were associated with higher odds of liver metastases and patients with lung metastases had lower risk of liver metastases at initial MBC diagnosis. The median overall survival of BCLM patients was 31.4 months and BCLM patients with HR+/HER2− subtype had the longest survival of 38.2 months. Older age, worse performance status, later stage of initial breast cancer, triple-negative subtype and lung metastases were significantly associated with a poorer prognosis in BCLM patients. Our study offers insights into the incidence and prognosis of BCLM patients at initial MBC diagnosis in Han population.

Persistent Inflammatory Stimulation Drives the Conversion of MSCs to Inflammatory CAFs That Promote Pro-Metastatic Characteristics in Breast Cancer Cells

The pro-inflammatory cytokines tumor necrosis factor α (TNFα) and interleukin 1β (IL-1β) are expressed simultaneously and have tumor-promoting roles in breast cancer. In parallel, mesenchymal stem cells (MSCs) undergo conversion at the tumor site to cancer-associated fibroblasts (CAFs), which are generally connected to enhanced tumor progression. Here, we determined the impact of consistent inflammatory stimulation on stromal cell plasticity. MSCs that were persistently stimulated by TNFα + IL-1β (generally 14-18 days) gained a CAF-like morphology, accompanied by prominent changes in gene expression, including in stroma/fibroblast-related genes. These CAF-like cells expressed elevated levels of vimentin and fibroblast activation protein (FAP) and demonstrated significantly increased abilities to contract collagen gels. Moreover, they gained the phenotype of inflammatory CAFs, as indicated by the reduced expression of α smooth muscle actin (αSMA), increased proliferation, and elevated expression of inflammatory genes and proteins, primarily inflammatory chemokines. These inflammatory CAFs released factors that enhanced tumor cell dispersion, scattering, and migration; the inflammatory CAF-derived factors elevated cancer cell migration by stimulating the chemokine receptors CCR2, CCR5, and CXCR1/2 and Ras-activating receptors, expressed by the cancer cells. Together, these novel findings demonstrate that chronic inflammation can induce MSC-to-CAF conversion, leading to the generation of tumor-promoting inflammatory CAFs.

Antimetastatic and Antitumor Activities of Orally Administered NAX014 Compound in a Murine Model of HER2-Positive Breast Cancer

The natural isoquinoline alkaloid Berberine (BBR) has been shown to possess several therapeutic effects, including anticancer activity. Different BBR derivatives have been designed and synthesized in order to obtain new compounds with enhanced anticancer efficacy. We previously showed that intraperitoneal (IP) administration of the BBR-derived NAX014 compound was able to counteract HER-2 overexpressing mammary tumors onset and progression in transgenic mice. However, the IP administration was found to induce organ toxicity at doses higher than 2.5 mg/Kg. In this study, we evaluated the effect of intragastric (IG) administration of 20 mg/kg of NAX014 on both safety and anticancer efficacy in HER-2/neu transgenic mice. Furthermore, cancer cell dissemination and migration, tumor cell senescence and immunological changes were examined. Our results demonstrated that IG NAX014 administration delayed the onset of mammary tumors with no negative effects on health and survival. NAX014 reduced HER-2 overexpressing BC cells migration in vitro and the frequency of lung metastasis in HER-2/neu transgenic mice. A statistically significant increase of senescence-associated p16 expression was observed in tumors from NAX014-treated mice, and the induction of cell senescence was observed in HER-2 overexpressing BC cells after in vitro treatment with NAX014. Although NAX014 did not modulate the presence of tumor-infiltrating lymphocytes, the level of circulating TNF-α and VEGF was found to be reduced in NAX014-treated mice. The overall results address the NAX014 compound as potential tool for therapeutic strategies against HER-2 overexpressing breast cancer.

Receptor Discordance of Metastatic Breast Cancer Depending on the Molecular Subtype

Introduction

Almost 30% of all women with early-stage breast cancer develop metastases. Treatment of metastatic disease is often based on the immunohistochemical information of the primary tumor, despite possible discordance of the hormone and Her2 receptor status.

Objectives

The aim of this study was to compare the receptor status of the primary tumor with the metastasis, and to evaluate for receptor discordance with regard to the molecular subtype, receptor status, and the localization of the metastases.

Methods

We retrospectively analyzed the data of all consecutive women with metastatic breast cancer, who underwent treatment at the Medical University Vienna between 2009 and 2016. Associations were calculated using the χ²or Fisher's exact test; years from primary diagnosis to metastatic disease were calculated using the Kaplan-Meier method.

Results

We identified 213 metastatic breast cancer patients, of whom 67 (31.5%) showed a discordant receptor status. Out of 32 patients with luminal A subtype, 14 (43.8%) had a switch of at least one receptor; 27 of 53 patients (50.9%) with luminal B subtype and 21 of 32 patients (65.6%) with Her2+ subtype showed receptor discordance; for triple-negative disease, 5 of 19 patients (36.3%) had a switch of at least one receptor. In 63 samples of bone metastases, 13 (20.6%) had discordant estrogen receptor status (p = 0.04). In 55 samples of bone metastases, 35 (63.3%) had discordant Her2 status (p = 0.002).

Conclusions

Our data show high rates of receptor discordance in metastatic breast cancer. Apart from the primary tumor, the immunohistochemical receptor status of the metastasis needs to be verified. This can lead to a change in treatment and prognosis.

Application of Biomarkers for the Prediction and Diagnosis of Bone Metastasis in Breast Cancer

The most common metastatic site of breast cancer is the bone. Metastatic bone disease can alter the integrity of the bone and cause serious complications, thereby greatly reducing health-related quality of life and leading to high medical costs. Although diagnostic methods and treatments for bone metastases (BM) are improving, some patients with early breast cancer who are at high risk of BM are not diagnosed early enough, leading to delayed intervention. Moreover, whole-body scintigraphy cannot easily distinguish BM from non-malignant bone diseases. To circumvent these issues, specific gene and protein biomarkers are being investigated for their potential to predict, diagnose, and evaluate breast cancer prognosis. In this review, we summarized the current biomarkers associated with BM in breast cancer and their role in clinical applications to assist in the diagnosis and treatment of BM in the future.

Safety and Efficacy of Long-Term Zoledronic Acid in Advanced Breast Cancer with Bone Metastasis in South China

Background

This retrospective study aimed to characterize the long-term (>24 months) safety profile of zoledronic acid (ZA). We aimed to investigate whether long-term ZA treatment had greater benefits than short-term treatment in patients from southern China with advanced breast cancer (ABC) with bone metastasis. Patients and Methods. A total of 566 metastatic breast cancer cases were included and divided into two groups according to the duration of ZA treatment. The included patients had at least one lytic bone lesion and had no skeletal-related events (SREs) prior to ZA therapy. The primary endpoint was to analyze the safety and long-term adverse effects, which covered osteonecrosis of jaws (ONJ), renal impairment, and hearing impairment. The second objective was to determine the efficacy of long-term ZA treatment by the incidence of SREs.

Results

Fifteen patients were diagnosed with ONJ (2.7%): nine in the short-term group (3.1%) and six in the long-term group (2.2%, P = 0.606). Five cases (0.9%) had renal function impairment: two in the short-term group (0.7%) and four in the long-term group (1.1%, P = 0.676). One patient (0.2%) in the long-term group had hearing impairment after 23 months of ZA treatment (0.4%, P = 0.482). In total, 103 cases in the short-term group (35.2%) and 138 cases in long-term group (50.5%) developed SREs (P < 0.001). The mean annual SRE rate was 0.3 in the short-term group (range, 0-3.1) versus 0.2 in the long-term group (0-1.0, P = 0.269). Subgroup analysis suggested that cases with non-load-bearing bone involvement and those who received systematic anticancer therapy without chemotherapy might benefit from long-term ZA treatment. Cox regression analysis indicated poor performance status, and nonvisceral organ involvement predicted high risk for SRE.

Conclusions

The extension of ZA treatment did not increase the long-term adverse events and reduced the annual incidence of SREs beyond 24 months. Although longer treatment of ZA over 24 months appeared to be safe, further prospective investigation is required.

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.

Diagnosis and Treatment of Bone Metastases in Breast Cancer: Radiotherapy, Local Approach and Systemic Therapy in a Guide for Clinicians

The standard care for metastatic breast cancer (MBC) is systemic therapies with imbrication of focal treatment for symptoms. Recently, thanks to implementation of radiological and metabolic exams and development of new target therapies, oligometastatic and oligoprogressive settings are even more common-paving the way to a paradigm change of focal treatments role. In fact, according to immunophenotype, radiotherapy can be considered with radical intent in these settings of patients. The aim of this literature review is to analyze available clinical data on prognosis of bone metastases from breast cancer and benefits of available treatments for developing a practical guide for clinicians.

Risk factors of distant metastasis after surgery among different breast cancer subtypes: a hospital-based study in Indonesia

Background

More than one third of breast cancer patients including those that are diagnosed in early stages will develop distant metastasis. Patterns of distant metastasis and the associated risks according to the molecular subtypes are not completely revealed particularly in populations of patients with delayed diagnosis and advanced stages.

Methods

Breast cancer patients (n = 1304) admitted to our institute (2014–2017) were evaluated to identify the metastatic patterns and the associated risks. Metastatic breast cancers at diagnosis were found in 245 patients (18.7%), and 1059 patients were then grouped into non-metastatic and metastatic groups after a median follow-up of 3.8 years.

Results

Infiltration of the tumor to the skin and chest wall prevailed as the most powerful predictor for distant metastasis (OR 2.115, 95% CI 1.544–2.898) particularly in the luminal A-like subtype (OR 2.685, 95% CI 1.649–4.371). Nodal involvement was also significantly associated with the risk of distant metastasis (OR 1.855, 95% CI 1.319–2.611), and the risk was higher in the Luminal A-like subtype (OR 2.572, 95% CI 1.547–4.278). Luminal A-like subtype had a significant higher risk of bone metastasis (OR 1.601, 95% CI 1.106–2.358). In respect to treatment, a combination of anthracyclines and taxanes-based chemotherapy was significantly associated with lower distant organ spread in comparison with anthracycline-based chemotherapy (OR 0.510, 95% CI 0.355–0.766) and the effect was stronger in Luminal A-like subtype (OR 0.417, 95% CI 0.226–0.769). Classification into Luminal and non-Luminal subtypes revealed significant higher risks of bone metastasis in the Luminal subtype (OR 1.793, 95% CI 1.209–2.660) and pulmonary metastasis in non-Luminal breast cancer (OR 1.445, 95% CI 1.003–2.083).

Conclusion

In addition to guiding the treatment plan, a comprehensive analysis of clinicopathological variables including the molecular subtypes could assist in the determination of distant metastasis risks of breast cancer patients. Our study offers new perspectives concerning the risks of distant metastasis in breast cancer subtypes in order to plan intensive surveillance or escalation of treatment particularly in a setting where patients are predominantly diagnosed in late stages.

De novo metastatic breast cancer: Subgroup analysis of molecular subtypes and prognosis

The purpose of the present study was to analyze the clinical and pathological characteristics, treatment, and prognosis of de novo metastatic breast cancer (DnMBC). Information regarding 1,890 patients treated for advanced breast cancer at the Tianjin Medical University Cancer Hospital between January 2008 to December 2017 was collected. Clinicopathological characteristics, treatments and outcomes of these patients were compared using the chi-square test, log-rank test, and Cox regression analysis. A total of 171 patients were diagnosed with DnMBC. The median age at diagnosis was 53 years (range, 23–77). The percentage of T4 staging was higher (37.4%), 69.6% of patients were estrogen receptor (ER) positive, 59.1% were progesterone receptor positive, 29.8% had positive human epidermal growth factor receptor 2 (HER2) status, 68.4% had Ki-67 ≥20%, 55% had oligometastasis at the initial diagnosis, ~87.7% were treated with chemotherapy initially and 24% received palliative surgery for the primary tumor. After a median follow-up time of 26 months, the median progression-free survival (PFS) and overall survival (OS) among patients with DnMBC were 11 (8.7–13.3) months and 34 (27.9–40.1) months, respectively. In the multivariable model, ER status and sites of first metastasis (oligometastasis or polymetastasis) were identified to be independent predictors of PFS (P<0.05); ER status, primary tumor stage, and surgical treatment of primary tumors were identified to be independent predictors of OS (P<0.05). In conclusion, the clinicopathological characteristics of DnMBC are greater invasiveness and a higher risk of progression. Palliative surgical treatment may improve the prognosis of HR+/HER2-patients with oligometastasis. Therefore, individualized treatment as required is particularly important.

Establishment and characterization of highly osteolytic luminal breast cancer cell lines by intracaudal arterial injection

Bone is one of the most common metastatic sites of breast cancer, and bone metastasis profoundly affects the quality of life of breast cancer patients. Bone metastasis is commonly observed among all the subtypes of breast cancer; however, its molecular mechanism has been analyzed only in triple-negative subtype of breast cancer (TNBC). To characterize the molecular mechanisms of bone metastasis of luminal breast cancer, we established a bone-metastatic model of the MCF7, luminal breast cancer cell line, with enhanced osteolytic activity by intracaudal arterial injection (CAI). Pathological analysis of the established cell lines revealed that they exhibited fierce osteolytic ability by promoting osteoclast differentiation and activity. The signature genes extracted from highly osteolytic MCF7 cell lines were differed from those of bone-metastatic TNBC cell lines. Our results suggest that unique mechanisms of osteolysis in bone-metastatic lesions of luminal breast cancer. In addition, several up-regulated genes in MCF7-BM (Bone Metastasis) 02 cell lines correlated with poor prognosis with luminal breast cancer patients. Our findings support further study on the bone-metastatic mechanisms of luminal breast cancer.

Impact of Docetaxel on blood-brain barrier function and formation of breast cancer brain metastases

BACKGROUND

Breast cancer (BC) is the most frequent malignant tumor in females and the 2nd most common cause of brain metastasis (BM), that are associated with a fatal prognosis. The increasing incidence from 10% up to 40% is due to more effective treatments of extracerebral sites with improved prognosis and increasing use of MRI in diagnostics. A frequently administered, potent chemotherapeutic group of drugs for BC treatment are taxanes usually used in the adjuvant and metastatic setting, which, however, have been suspected to be associated with a higher incidence of BM. The aim of our study was to experimentally analyze the impact of the taxane docetaxel (DTX) on brain metastasis formation, and to elucidate the underlying molecular mechanism.

METHODS

A monocentric patient cohort was analyzed to determine the association of taxane treatment and BM formation. To identify the specific impact of DTX, a murine brain metastatic model upon intracardial injection of breast cancer cells was conducted. To approach the functional mechanism, dynamic contrast-enhanced MRI and electron microscopy of mice as well as in-vitro transendothelial electrical resistance (TEER) and tracer permeability assays using brain endothelial cells (EC) were carried out. PCR-based, immunohistochemical and immunoblotting analyses with additional RNA sequencing of murine and human ECs were performed to explore the molecular mechanisms by DTX treatment.

RESULTS

Taxane treatment was associated with an increased rate of BM formation in the patient cohort and the murine metastatic model. Functional studies did not show unequivocal alterations of blood-brain barrier properties upon DTX treatment in-vivo, but in-vitro assays revealed a temporary DTX-related barrier disruption. We found disturbance of tubulin structure and upregulation of tight junction marker claudin-5 in ECs. Furthermore, upregulation of several members of the tubulin family and downregulation of tetraspanin-2 in both, murine and human ECs, was induced.

CONCLUSION

In summary, a higher incidence of BM was associated with prior taxane treatment in both a patient cohort and a murine mouse model. We could identify tubulin family members and tetraspanin-2 as potential contributors for the destabilization of the blood-brain barrier. Further analyses are needed to decipher the exact role of those alterations on tumor metastatic processes in the brain.

Dynamic interactions between the extracellular matrix and estrogen activity in progression of ER+ breast cancer

Metastatic, anti-estrogen resistant estrogen receptor α positive (ER+) breast cancer is the leading cause of breast cancer deaths in U.S. women. While studies have demonstrated the importance of the stromal tumor microenvironment in cancer progression and therapeutic responses, effects on the responses of ER+ cancers to estrogen and anti-estrogens are poorly understood, particularly in the complex in vivo environment. In this study, we used an estrogen responsive syngeneic mouse model to interrogate how a COL1A1-enriched fibrotic ECM modulates integrated hormonal responses in cancer progression. We orthotopically transplanted the ER+ TC11 cell line into wild-type (WT) or collagen-dense (Col1a1^tm1Jae/+, mCol1a1) syngeneic FVB/N female mice. Once tumors were established, recipients were supplemented with 17β-estradiol (E2), tamoxifen, or left untreated. Although the dense/stiff environment in mCol1a1 recipients did not alter the rate of E2-induced proliferation of the primary tumor, it fostered the agonist activity of tamoxifen to increase proliferation and AP-1 activity. Manipulation of estrogen activity did not alter the incidence of lung lesions in either WT or mCol1a1 hosts. However, the mCol1a1 environment enabled tamoxifen-stimulated growth of pulmonary metastases and further fueled estrogen-driven growth. Moreover, E2 remodeled peritumoral ECM architecture in WT animals, modifying alignment of collagen fibers and altering synthesis of ECM components associated with increased alignment and stiffness, and increasing FN1 and POSTN expression in the pulmonary metastatic niche. These studies demonstrate dynamic interactions between ECM properties and estrogen activity in progression of ER+ breast cancer, and support the need for therapeutics that target both ER and the tumor microenvironment.

Risk factors for distant metastasis of patients with primary triple-negative breast cancer

Objective: Triple-negative breast cancer (TNBC) involves higher rates of recurrence and distant metastasis. The present study sought to characterize the risk factors for distant metastasis of TNBC.

Methods: The Surveillance, Epidemiology, and End Results (SEER) database was exploited to enroll patients diagnosed with TNBC from 2010 to 2015. The eligible patients were dichotomized into locoregional and distant metastasis at the time of diagnosis. Patients’ demographics and tumor features, and treatment were evaluated to identify the risk factors for distant metastasis of primary TNBC. The categorical variables were examined by chi-square tests. Univariate and multivariate logistic regression analyses were used to determine the risk factors for distant metastasis. Breast cancer-specific survival (BCSS) and overall survival (OS) were estimated by Kaplan–Meier plots with log-rank tests.

Results: We collected 26863 patients with primary TNBC, 1330 (5.0%) of them presented with distant metastasis. In the univariate analysis, all the variables indicated statistical significance. The significant variables were subsequently enlisted into the multivariate logistic regression analysis. Age > 50, higher clinical stage T and N, and tumor size > 5 cm were independent risk factors for distant metastasis of primary TNBC. Moreover, higher clinical stage T and stage N were independent risk factors for bone metastasis of the patients. TNBC patients with either bone or visceral metastasis have poor survival, with brain metastasis worst of all, though the OS difference was not statistically significant.

Conclusions: TNBC patients with larger age, higher clinical stage, larger tumor size were more predisposed to have distant metastasis. Great attention should be paid to the prognosis of these patients with distant metastasis.

Reclassification of breast cancer: Towards improved diagnosis and outcome

BACKGROUND

The subtyping of breast cancer based on features of tumour biology such as hormonal receptor and HER2 status has led to increasingly patient-specific treatment and thus improved outcomes. However, such subgroups may not be sufficiently informed to best predict outcome and/or treatment response. The incorporation of multi-modal data may identify unexpected and actionable subgroups to enhance disease understanding and improve outcomes.

METHODS

This retrospective cross-sectional study used the cancer registry Surveillance, Epidemiology and End Results (SEER), which represents 28% of the U.S. population. We included adult female patients diagnosed with breast cancer in 2010. Latent class analysis (LCA), a data-driven technique, was used to identify clinically homogeneous subgroups ("endophenotypes") of breast cancer from receptor status (hormonal receptor and HER2), clinical, and demographic data and each subgroup was explored using Bayesian networks.

RESULTS

Included were 44,346 patients, 1257 (3%) of whom had distant organ metastases at diagnosis. Four endophenotypes were identified with LCA: 1) "Favourable biology" had entirely local disease with favourable biology, 2) "HGHR-" had the highest incidence of HR- receptor status and highest grade but few metastases and relatively good outcomes, 3) "HR+ bone" had isolated bone metastases and uniform receptor status (HR+/HER2-), and 4) "Distant organ spread" had high metastatic burden and poor survival. Bayesian networks revealed clinically intuitive interactions between patient and disease features.

CONCLUSIONS

We have identified four distinct subgroups of breast cancer using LCA, including one unexpected group with good outcomes despite having the highest average histologic grade and rate of HR- tumours. Deeper understanding of subgroup characteristics can allow us to 1) identify actionable group properties relating to disease biology and patient features and 2) develop group-specific diagnostics and treatments.

Treatment response as predictor for brain metastasis in triple negative breast cancer: A score-based model

BACKGROUND

Triple negative breast cancer (TNBC) has worse prognosis than other subtypes of breast cancer, and many patients develop brain metastasis (BM). We developed a simple predictive model to stratify the risk of BM in TNBC patients receiving neo-adjuvant chemotherapy (NAC), surgery, and radiation therapy (RT).

METHODS

Patients with TNBC who received NAC, surgery, and RT were included. Cox proportional hazards method was used to evaluate factors associated with BM. Significant factors predictive for BM on multivariate analysis (MVA) were used to develop a risk score. Patients were divided into three risk groups: low, intermediate, and high. A receiver operating characteristic (ROC) curve was drawn to evaluate the value of the risk group in predicting BM. This predictive model was externally validated.

RESULTS

A total of 160 patients were included. The median follow-up was 47.4 months. The median age at diagnosis was 49.9 years. The 2-year freedom from BM was 90.5%. Persistent lymph node positivity, HR 8.75 (1.76-43.52, P = 0.01), and lack of downstaging, HR 3.46 (1.03-11.62, P = 0.04), were significant predictors for BM. The 2-year rate of BM was 0%, 10.7%, and 30.3% (P < 0.001) in patients belonging to low-, intermediate-, and high-risk groups, respectively. Area under the ROC curve was 0.81 (P < 0.001). This model was externally validated (C-index = 0.79).

CONCLUSIONS

Lack of downstaging and persistent lymph node positivity after NAC are associated with development of BM in TNBC. This model can be used by the clinicians to stratify patients into the three risk groups to identify those at increased risk of developing BM and potentially impact surveillance strategies.

ER+/HER2+ Breast Cancer Has Different Metastatic Patterns and Better Survival Than ER-/HER2+ Breast Cancer

BACKGROUND

Human epidermal growth factor receptor 2-positive (HER2⁺) breast cancer is generally treated with HER2-targeted therapy combined with chemotherapy. Patients with HER2⁺ and estrogen receptor-positive (ER⁺) cancer are additionally treated with long-term hormone therapy. This study examined the metastatic pattern and prognosis of both ER⁺/HER2⁺ and ER^-/HER2⁺ breast cancer.

PATIENTS AND METHODS

A total of 54,147 patients with HER2⁺ breast cancer from the National Cancer Data Base (NCDB, 2010-2013) and 31,946 patients with HER2⁺ breast cancer from the Surveillance, Epidemiology, and End Results Program (SEER, 2010-2014) were examined. Sites of metastasis and overall survival (OS) were examined in the NCDB, while OS and breast cancer-specific survival were examined in the SEER database.

RESULTS

Compared to ER^-/HER2⁺ breast cancer, ER⁺/HER2⁺ breast cancer was more likely to metastasize to bone but less likely to brain, liver, and lung and less likely to result in multiple metastases. In univariate analysis based on the NCDB, patients with ER^-/HER2⁺ breast cancer had worse OS in all metastasis subsets, including patients who received HER2-targeted therapy. This poor survival for ER^-/HER2⁺ persisted in patients with metastasis to bone and lung, and multiple metastases. In multivariate analysis adjusting for age, tumor grade, surgery, chemotherapy, HER2-targeted therapy, and hormone therapy, ER^-/HER2⁺ patients with bone metastasis still had worse OS. In the SEER, ER^-/HER2⁺ patients had both worse OS and breast cancer-specific survival in univariate analysis.

CONCLUSION

This large study showed patients with ER⁺/HER2⁺ and ER^-/HER2⁺ breast cancers had different metastatic patterns. Patients with ER^-/HER2⁺ breast cancer may require more aggressive treatment.

Breast Cancer Recurrence Risk Assessment: Is Non-Invasive Monitoring an Option?

BACKGROUND

Metastatic breast cancer (MBC) represents a life-threatening disease with a median survival time of 18-24 months that often can only be treated palliatively. The majority of women suffering from MBC are those who had been previously diagnosed with locally advanced disease and subsequently experienced cancer recurrence in the form of metastasis. However, according to guidelines, no systemic follow-up for monitoring purposes is recommended for these women. The purpose of this article is to review current methods of recurrent risk assessment as well as non-invasive monitoring options for women at risk for distant disease relapse and metastasis formation.

METHODS

We used PubMed and national guidelines, such as the National Comprehensive Cancer Network (NCCN), to find recently published studies on breast cancer recurrence risk assessment and systemic monitoring of breast cancer patients through non-invasive means.

RESULTS

The options for recurrence risk assessment of locally invasive breast cancer has improved due to diverse genetic tests, such as Oncotype DX, MammaPrint, the PAM50 (now known as the "Prosigna Test") assay, EndoPredict (EP), and the Breast Cancer Index (BCI), which evaluate a women's risk of relapse according to certain cancer-gene expression patterns. Different promising non-invasive urinary protein-based biomarkers with metastasis surveillance potential that have been identified are MMP-2, MMP-9, NGAL, and ADAM12. In particular, ααCTX, ββCTX, and NTX could help to monitor bone metastasis.

CONCLUSION

In times of improved recurrence risk assessment of women with breast cancer, non-invasive biomarkers are urgently needed as potential monitoring options for women who have an increased risk of recurrence. Urine as a bioliquid of choice provides several advantages - it is non-invasive, can be obtained easily and frequently, and is economical. Promising biomarkers that could help to follow up women with increased recurrence risk have been identified. In order for them to be implemented in clinical usage and national guideline recommendations, further validation in larger independent cohorts will be needed.

A phase II clinical trial of the Aurora and angiogenic kinase inhibitor ENMD-2076 for previously treated, advanced, or metastatic triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) remains an aggressive breast cancer subtype with limited treatment options. ENMD-2076 is a small-molecule inhibitor of Aurora and angiogenic kinases with proapoptotic and antiproliferative activity in preclinical models of TNBC.

METHODS

This dual-institution, single-arm, two-stage, phase II clinical trial enrolled patients with locally advanced or metastatic TNBC previously treated with one to three prior lines of chemotherapy in the advanced setting. Patients were treated with ENMD-2076 250 mg orally once daily with continuous dosing in 4-week cycles until disease progression or unacceptable toxicity occurred. The primary endpoint was 6-month clinical benefit rate (CBR), and secondary endpoints included progression-free survival, pharmacokinetic profile, safety, and biologic correlates in archival and fresh serial tumor biopsies in a subset of patients.

RESULTS

Forty-one patients were enrolled. The 6-month CBR was 16.7% (95% CI, 6-32.8%) and included two partial responses. The 4-month CBR was 27.8% (95% CI, 14-45.2%), and the average duration of benefit was 6.5 cycles. Common adverse events included hypertension, fatigue, diarrhea, and nausea. Treatment with ENMD-2076 resulted in a decrease in cellular proliferation and microvessel density and an increase in p53 and p73 expression, consistent with preclinical observations.

CONCLUSIONS

Single-agent ENMD-2076 treatment resulted in partial response or clinical benefit lasting more than 6 months in 16.7% of patients with pretreated, advanced, or metastatic TNBC. These results support the development of predictive biomarkers using archival and fresh tumor tissue, as well as consideration of mechanism-based combination strategies.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01639248 . Registered on July 12, 2012.

Population-based validation of the National Cancer Comprehensive Network recommendations for breast cancer staging

OBJECTIVE

The aim of the current study is to evaluate the performance characteristics of the National Comprehensive Cancer Network (NCCN) staging recommendations for breast cancer with regard to the detection of lung, bone, and liver metastases.

METHODS

Surveillance, epidemiology, and end points (SEER) database (2010-2015) was accessed, and patients with breast cancer and complete information about T stage and clinical N stage, ER status, Her2 status, and metastatic sites were extracted. Performance characteristics evaluated for the current study included sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), number needed to investigate (NNI), and accuracy.

RESULTS

A total of 239,196 patients were included in the analysis. For the overall cohort, the required PPV (for the recognition of lung metastases) is 10.6% and NNI to detect one case of lung metastasis is 9.4. Likewise, PPV (for the recognition of bone metastases) is 18.6% and NNI to detect one case of bone metastasis is 5.3. Moreover, PPV (for the recognition of liver metastases) is 7.6% and NNI to detect one case of liver metastasis is 13.1. When changing the threshold for baseline imaging to includeT2N1 patients, a better balance between sensitivity and specificity among ER+/Her2- patients (> 92% for both sensitivity and specificity for the three metastatic sites) was observed. On the other hand, the proposed change improved sensitivity while it lowers significantly the specificity among Her2+ and triple negative subtypes (specificity < 84% for Her2+ disease for the three metastatic sites; specificity < 87% for triple negative disease for the three metastatic sites).

CONCLUSION

The current NCCN recommendations for breast cancer staging have an excellent NPV and miss only few patients with lung, liver, or bone metastases. Future studies incorporating the subtype of breast cancer as a determinant of staging pathway is needed.

A Nomogram for Distinction and Potential Prediction of Liver Metastasis in Breast Cancer Patients

Liver metastasis from breast cancer has poor prognosis. We aimed at developing a reliable tool for making a distinction and prediction for liver metastasis in breast cancer patients, thus helping clinical diagnosis and treatment. In this study, totally 6238 patients from SEER database with known distant metastasis status and clinicopathologic variables were enrolled and divided randomly into training and validating groups. Logistic regression was used to screen variables and a nomogram was constructed. After multivariate logistic regression, sex, histology type, N stage, grade, age, ER, PR, HER2 status as significant variables for constructing the nomogram. The nomogram for distinguishing and predicting liver metastasis in breast cancer passed the calibration and validation steps and the areas under the receiver operating characteristic curve of the training set and the validation set were 0.6602 and 0.6511 respectively. Our nomogram is a reliable and robust tool for the distinction and prediction of liver metastasis in breast cancer patients, thus helping better choose medical examinations and optimize therapeutic regimen under the cooperation among medical oncologists and surgeons.

LAPTM4B gene copy number gain is associated with inferior response to anthracycline-based chemotherapy in hormone receptor negative breast carcinomas

PURPOSE

To determine the associations between lysosomal-associated transmembrane protein 4b (LAPTM4B) gene copy number and response to different chemotherapy regimens in hormone receptor negative (HR-) primary breast carcinomas.

PATIENTS AND METHODS

Two cohorts were analyzed: (1) 69 core biopsies from HR-breast carcinomas treated with neoadjuvant chemotherapy (anthracycline based in 72.5% of patients and non-anthracycline based in 27.5% of patients). (2) Tissue microarray (TMA) of 74 HR-breast carcinomas treated with adjuvant therapy (77.0% of the patients received anthracycline, 17.6% of the patients non-anthracycline-based therapy, and in 5.4% of the cases, no treatment data are available). Interphase FISH technique was applied on pretreatment core biopsies (cohort I) and on TMAs (cohort II) using custom-made dual-labelled FISH probes (LAPTM4B/CEN8q FISH probe Abnova Corp.).

RESULTS

In the neoadjuvant cohort in the anthracycline-treated group, we observed a significant difference (p = 0.029) of average LAPTM4B copy number between the non-responder and pathological complete responder groups (4.1 ± 1.1 vs. 2.6 ± 0.1). In the adjuvant setting, the anthracycline-treated group of metastatic breast carcinomas was characterized by higher LAPTM4B copy number comparing to the non-metastatic ones (p = 0.046). In contrast, in the non-anthracycline-treated group of patients, we did not find any LAPTM4B gene copy number differences between responder vs. non-responder groups or between metastatic vs. non-metastatic groups.

CONCLUSION

Our results confirm the possible role of the LAPTM4B gene in anthracycline resistance in HR- breast cancer. Analyzing LAPTM4B copy number pattern may support future treatment decision.

Risk factors and survival outcomes in patients with breast cancer and lung metastasis: a population-based study

The risk factors for morbidity and mortality in breast cancer lung metastases (BCLM) patients still remain poorly identified. The aim of this study was to assess the incidence and survival of BCLM and associated risk factors. Patients with BCLM were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Multivariate logistic regression analysis was used to determine the risk factors for BCLM. Predictors of factors associated with death were analyzed in Cox regression and Fine and Gray's test. Of the 11568 patients with stage IV breast cancer, 4213 (36.4%) had BCLM and 1214 (10.5%) had metastases confined to lungs. The median survival time for patients with BCLM was 21 months, and 15.5% of the patients were alive more than 3 years. The tumor subtype distribution was 45.3% HR⁻/HER2⁻, 12.2% HR⁺/HER2⁺, 7.8% HR⁻/HER2^+, and 15.0% triple‐negative subtype. Compared with patients without BCLM, those with BCLM were more likely to be aged, female, black, higher tumor grade, HR⁻/HER2⁺, HR⁺/HER2^+, and triple‐negative subtypes at diagnosis. Survival analysis showed that the aged, black race, HR⁻/HER2⁺, triple‐negative subtype, higher grade were the independent risk factor for BCLM patients’ survival, while HR⁺/HER2⁺ subtype, insured status, and married status suggested better prognosis. In conclusion, the incidence and prognosis of BCLM varied by tumor subtypes, age, and race. Elderly patients with HER2‐positive or triple‐negative tumors were more likely to have BCLM.

The role of biomarkers in the management of bone-homing malignancies

Bone represents a common site of metastasis from several solid tumours, including breast, prostate and lung malignancies. The onset of bone metastases (BM) is associated not only with serious skeletal complications, but also shortened overall survival, owing to the lack of curative treatment options for late-stage cancer.

Despite the diagnostic advances, BM detection often occurs in the symptomatic stage, underlining the need for novel strategies aimed at the early identification of high-risk patients. To this purpose, both bone turnover and tumour-derived markers are being investigated for their potential diagnostic, prognostic and predictive roles.

In this review, we summarize the pathogenesis of BM in breast, prostate and lung tumours, while exploring the current research focused on the identification and clinical validation of BM biomarkers.

Breast cancer subtype and stage are prognostic of time from breast cancer diagnosis to brain metastasis development

Breast cancer brain metastasis (BCBM) is associated with high morbidity and mortality. Patients with breast cancer risk factors associated with rapid development of BCBM could potentially benefit from early brain metastasis screening. We retrospectively reviewed all BCBM patients treated with brain radiotherapy at our institution from 1997 to 2015. Interval time to BCBM was defined as date of pathologic breast cancer diagnosis to date of radiographic evidence of brain metastasis. Patients were stratified by breast cancer molecular subtype and stage at diagnosis. Kaplan Meier analysis was conducted on time to development of BCBM. Breast cancer risk factors were correlated with time to BCBM on Cox proportion hazard analysis. The study cohort comprised 121 BCBM patients, with median interval time to BCBM of 46 months. Times to BCBM for Her2+/2HR+, Her2+, Her2-/HR+, and triple-negative (TNBC) subtypes were 70, 44, 42, and 28 months respectively (p = 0.002). Time to BCBM for stages I, II, III, and IV were 70, 54, 29, and 24 months, respectively (p = 0.000). BCBM patients were further stratified by both molecular subtype (TNBC vs. non-TNBC) and stage (I, II vs. III, IV). Median times to BCBM for non-TNBC/stage I-II, TNBC/stage I-II, non-TNBC stage III-IV, and TNBC/stage III-IV were 68, 47, 29, and 6 months respectively (p = 0.000). Subtype and stage were associated with shorter time to BCBM on multivariate analysis. Subtype and initial stage are independently correlated with decreased time to development of BCBM. Patients with advanced high stage and triple negative breast cancer develop brain metastases significantly earlier.

Immune Modulation by Vitamin D: Special Emphasis on Its Role in Prevention and Treatment of Cancer

PURPOSE

Vitamin D has been known to be involved in mineral and bone homeostasis for many years. In the past its main use was in treating osteoporosis and rickets. In recent years it was found that vitamin D is an immune-modulating agent and may also have a role in several diseases, including autoimmune diseases. The immune-modulating effects appear to be mediated by vitamin D interaction with the vitamin D receptor (VDR) that has transcriptional effects and is expressed on various cell types, especially those of the immune system. Immunologic and rheumatologic diseases were the first to be studied, but at the moment the spotlight is on the interactions between tumor cells and vitamin D. This review focuses on four forms of cancer that apparently benefit from a vitamin D supplementation during treatment: prostate, breast, and colorectal cancers and melanoma. Several studies reported that differences exist between white and black patients, which we discuss in the review.

METHODS

We systematically searched PubMed for studies published in English. The search terms included vitamin D, cancer, breast, colorectal, prostate, and melanoma.

FINDINGS AND IMPLICATIONS

Our findings show that vitamin D has the potential to become a valid coadjuvant in the treatment of cancer.