Immunotherapy in breast cancer: an overview of current strategies and perspectives

Investigation and validation of neurotransmitter receptor-related biomarkers for forecasting clinical outcomes and immunotherapeutic efficacy in breast cancer

PURPOSE

The prognostic role of neurotransmitters and their receptors in breast cancer (BC) has not been fully investigated. The aim of this study was to construct a survival model for the prognosis of BC patients based on neurotransmitter receptor-related genes (NRRGs).

METHODS

BC-related differentially expressed genes (DEGs) were screened and intersected with NRRGs. GO, KEGG and PPI analyses were performed. Univariate Cox, Least Absolute Shrinkage and Selection Operator (LASSO) and multivariate Cox regression analyses were used to construct prognostic models for biomarker expression levels. The model was validated using an external validation set. The receiver operating characteristic curves (ROC) for diagnostic value prediction and clinicopathologic characteristic nomogram were constructed. qRT-PCR was used for further in vitro validation experiments.

RESULTS

Forty-five overlapping genes were obtained by intersecting BC-related DEGs with 172 NRRGs. Univariate Cox, LASSO and multivariate Cox regression analyses were used to construct prognostic models for the expression levels of biomarkers including DLG3, SLC1A1, PSCA and PRKCZ. The feasibility of the model was validated by the GEO validation set. ROC curves were established for diagnostic value prediction. Patients in the high-risk group had a worse prognosis, higher TMB score, higher probability of gene mutation, and higher immune cell infiltration. RiskScore, M, N and Age were strongly correlated with survival. The mRNA expression levels of DLG3, PSCA and PRKCZ in the BC group were significantly higher than those in the control group.

CONCLUSION

Risk prediction model based on DLG3, SLC1A1, PSCA and PRKCZ, which are closely related to BC prognosis, was successfully constructed.

Amelioration of breast cancer therapies through normalization of tumor vessels and microenvironment: paradigm shift to improve drug perfusion and nanocarrier permeation

Breast cancer (BC) is the most commonly diagnosed cancer among women. Chemo-, immune- and photothermal therapies are employed to manage BC. However, the tumor microenvironment (TME) prevents free drugs and nanocarriers (NCs) from entering the tumor premises. Formulation scientists rely on enhanced permeation and retention (EPR) to extravasate NCs in the TME. However, recent research has demonstrated the inconsistent nature of EPR among different patients and tumor types. In addition, angiogenesis, high intra-tumor fluid pressure, desmoplasia, and high cell and extracellular matrix density resist the accumulation of NCs in the TME. In this review, we discuss TME normalization as an approach to improve the penetration of drugs and NCSs in the tumor premises. Strategies such as normalization of tumor vessels, reversal of hypoxia, alleviation of high intra-tumor pressure, and infiltration of lymphocytes for the reversal of therapy failure have been discussed in this manuscript. Strategies to promote the infiltration of anticancer immune cells in the TME after vascular normalization have been discussed. Studies strategizing time points to administer TME-normalizing agents are highlighted. Mechanistic pathways controlling the angiogenesis and normalization processes are discussed along with the studies. This review will provide greater tumor-targeting insights to the formulation scientists.

Enhancing the anti-tumor activity and reprogramming M2 macrophages by delivering siRNAs against SIRPα and STAT6 via M1 exosomes and combining with anti-PD-L1

BACKGROUND

The invasive property of breast cancer and the complex composition of the tumor microenvironment (TME) antibodies like anti-PD-L1, can inhibit tumor growth by promoting macrophage phagocytosis. In this research, we used anti-PD-L1 antibody and siRNAs targeting SIRPα (siSIRPα) and STAT6 (siSTAT6). The siRNAs were transported to macrophages using M1-derived exosomes.

METHODS

For this purpose, exosomes were isolated from the supernatant of lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Next, siSIRPα and siSTAT6 were electroporated into the M1-exosomes. M1-exosomes without siRNA or loaded with different siRNAs were used to treat M2 macrophages. Then, the polarization of macrophages was evaluated. By co-culturing of treated macrophages with 4T1 cells, anti-tumor functions of macrophages were assessed.

RESULTS

It was demonstrated that siRNA-loaded M1-exosomes induced macrophage polarization into an M1 phenotype and promoted the anti-tumor effects of macrophages as shown by a reduction in migration, invasion and proliferation of 4T1 cells, as well as an enhancement of phagocytosis of 4T1 cells by macrophages.

CONCLUSION

This study demonstrated the potential of a multifaceted therapeutic approach targeting TAMs to enhance anti-tumor immune responses in breast cancer.

Tumor microenvironment and immunotherapy for triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a subtype of breast cancer known for its high aggressiveness and poor prognosis. Conventional treatment of TNBC is challenging due to its heterogeneity and lack of clear targets. Recent advancements in immunotherapy have shown promise in treating TNBC, with immune checkpoint therapy playing a significant role in comprehensive treatment plans. The tumor microenvironment (TME), comprising immune cells, stromal cells, and various cytokines, plays a crucial role in TNBC progression and response to immunotherapy. The high presence of tumor-infiltrating lymphocytes and immune checkpoint proteins in TNBC indicates the potential of immunotherapeutic strategies. However, the complexity of the TME, while offering therapeutic targets, requires further exploration of its multiple roles in immunotherapy. In this review, we discuss the interaction mechanism between TME and TNBC immunotherapy based on the characteristics and composition of TME, and elaborate on and analyze the effect of TME on immunotherapy, the potential of TME as an immune target, and the ability of TME as a biomarker. Understanding these dynamics will offer new insights for enhancing therapeutic approaches and investigating stratification and prognostic markers for TNBC patients.

Knowledge mapping of immunotherapy for breast cancer: A bibliometric analysis from 2013 to 2022

Breast cancer is the leading cause of cancer-related death among women globally. Immunotherapy has emerged as a major milestone in contemporary oncology. This study aims to conduct a bibliometric analysis in the field of immunotherapy for breast cancer, providing a comprehensive overview of the current research status, identifying trends and hotspots in research topics. We searched and retrieved data from the Web of Science Core Collection, and performed a bibliometric analysis of publications on immunotherapy for breast cancer from 2013 to 2022. Current status and hotspots were evaluated by co-occurrence analysis using VOSviewer. Evolution and bursts of knowledge base were assessed by co-citation analysis using CiteSpace. Thematic evolution by bibliometrix package was used to discover keywords trends. The attribution and collaboration of countries/regions, institutions and authors were also explored. A total of 7,975 publications were included. In co-occurrence analysis of keywords, 6 major clusters were revealed: tumor microenvironment, prognosis biomarker, immune checkpoints, novel drug delivery methods, immune cells and therapeutic approaches. The top three most frequently mentioned keywords were tumor microenvironment, triple-negative breast cancer, and programmed cell death ligand 1. The most productive country, institution and author were the USA (2926 publications), the University of Texas MD Anderson Cancer Center (219 publications), and Sherene Loi (28 publications), respectively. There has been a rapid growth in studies on immunotherapy for breast cancer worldwide. This research area has gained increasing attention from different countries and institutions. With the rising incidence of breast cancer, immunotherapy represents a research field of significant clinical value and potential.

The Train: A Supply of Inspiration for Delivering High-Quality Cancer Care

BACKGROUND

The past 10 years have convincingly shown that the TRAIN-studies, with their starting point in Antoni van Leeuwenhoek (Amsterdam), have proved their significance for breast cancer patients with stage II or III human epidermal growth factor receptor 2 (HER2)-positive breast cancer. The main aim of these studies is to maximize a positive, clinically relevant outcome with the least burdensome neoadjuvant systemic treatment option after which surgery and systemic treatment (in accordance with the current oncology guidelines) is provided.

RATIONALE AND CONCLUSIONS

The breast cancer train studies give rise to plenty of ideas for optimization of treatment in oncology, which is in the best interest of the patient, the treating doctor or caregiver, and society. By developing new, forthcoming ideas, the train is moving steadily and constantly, with high-quality treatment and care expected only to continue rising.

CDK4/6 inhibitors in HR-positive breast cancer immunotherapy

Breast cancer is the most prevalent malignant tumour among women. Approximately 70 % of patients are hormone receptor (HR)-positive and undergo endocrine therapy as the main form of treatment; however, the efficacy of this type of therapy is limited by some factors, such as drug resistance and complex tumour microenvironments. Using network pharmacology and molecular docking, this study examined how CDK4/6 inhibitors enhance the effects of immunotherapy for HR-positive breast cancer, focusing on their effects on the tumour microenvironment (TME) and immune cell activity. CDK4/6 inhibitor influence crucial signalling pathways, including TP53 and EGFR, underscoring their importance in modulating immune responses and combating drug resistance. Our analysis revealed that the combination of CDK4/6 inhibitors with other immunotherapies, such as immune checkpoint inhibitors, might play an important role in improving the effectiveness of treatment in patients with cancer. This study provides new perspectives on treatment options for HR-positive breast cancers, promoting ongoing research and improvements in therapeutic approaches.

Modeling intratumor heterogeneity in breast cancer

Reduced therapy response in breast cancer has been correlated with heterogeneity in biomarker composition, expression level, and spatial distribution of cancer cells within a patient tumor. Thus, there is a need for models to replicate cell-cell, cell-stromal, and cell-microenvironment interactions during cancer progression. Traditional two-dimensional (2D) cell culture models are convenient but cannot adequately represent tumor microenvironment histological organization,in vivo3D spatial/cellular context, and physiological relevance. Recently, three-dimensional (3D)in vitrotumor models have been shown to provide an improved platform for incorporating compositional and spatial heterogeneity and to better mimic the biological characteristics of patient tumors to assess drug response. Advances in 3D bioprinting have allowed the creation of more complex models with improved physiologic representation while controlling for reproducibility and accuracy. This review aims to summarize the advantages and challenges of current 3Din vitromodels for evaluating therapy response in breast cancer, with a particular emphasis on 3D bioprinting, and addresses several key issues for future model development as well as their application to other cancers.

Chitosan-derived drug free "artificial beacon" simulating immunogenetic cell death cascade effector to initiate immune response for cancer therapy

Immunogenetic cell death (ICD) is widely participated in tumor immune therapy. However, the stress responses triggered by individual ICD inducers are typically not strong enough to effectively kickstart an ICD effect and successful ICD necessitates a high level of ICD stimulus, which may be linked to dose-related toxicity. In this research, we developed a drug-free "artificial beacon" ATP/CSO@ECM that mimics the ICD cascade system to kickstart an immune response with cationic chitosan (CSO) as a bridge, which participated in integrating tumor antigens and functional damage-associated molecular patterns (DAMPs) into one effector by electrostatic interaction. This beacon is made up of ATP/CSO nanocomplexes covered by an engineered cell membrane (ECM), which is verified to enrich with high mobility group box 1 (HMGB1) and calreticulin (CRT). When exposed to the acidic tumor environment, the ATP/CSO@ECM underwent a morphological change by proton buffering capability of CSO. This resulted in the release of simulated DAMPs and the adjuvant CSO, all of which collaborated to activate dendritic cells and ultimately prolong the effectiveness of immunotherapy. This chitosan-derived "artificial beacon" ATP/CSO@ECM fully mobilizes the function of CSO and avoids the insufficient ICD effect by concentrating signaling molecules, providing a hopeful strategy for using the ICD process in targeted cancer therapy.

Staphylococcus epidermidis biofilm in inflammatory breast cancer and its treatment strategies

Bacterial biofilms represent a significant challenge in both clinical and industrial settings because of their robust nature and resistance to antimicrobials. Biofilms are formed by microorganisms that produce an exopolysaccharide matrix, protecting function and supporting for nutrients. Among the various bacterial species capable of forming biofilms, Staphylococcus epidermidis, a commensal organism found on human skin and mucous membranes, has emerged as a prominent opportunistic pathogen, when introduced into the body via medical devices, such as catheters, prosthetic joints, and heart valves. The formation of biofilms by S. epidermidis on these surfaces facilitates colonization and provides protection against host immune responses and antibiotic therapies, leading to persistent and difficult-to-treat infections. The possible involvement of biofilms for breast oncogenesis has recently created the curiosity. This paper therefore delves into S. epidermidis biofilm involvement in breast cancer. S. epidermidis biofilms can create a sustained inflammatory environment through their metabolites and can break DNA in breast tissue, promoting cellular proliferation, angiogenesis, and genetic instability. Preventing biofilm formation primarily involves preventing bacterial proliferation using prophylactic measures and sterilization of medical devices and equipment. In cancer treatment, common modalities include chemotherapy, surgery, immunotherapy, alkylating agents, and various anticancer drugs. Understanding the relationship between anticancer drugs and bacterial biofilms is crucial, especially for those undergoing cancer treatment who may be at increased risk of bacterial infections, for improving patient outcomes. By elucidating these interactions, strategies to prevent or disrupt biofilm formation, thereby reducing the incidence of infections associated with medical devices and implants, can be identified.

Polyphenols as Immunomodulators and Epigenetic Modulators: An Analysis of Their Role in the Treatment and Prevention of Breast Cancer

Breast cancer poses a substantial health challenge for women globally. Recently, there has been a notable increase in scholarly attention regarding polyphenols, primarily attributed to not only the adverse effects associated with conventional treatments but also their immune-preventive impacts. Polyphenols, nature-derived substances present in vegetation, including fruits and vegetables, have received considerable attention in various fields of science due to their probable wellness merits, particularly in the treatment and hindrance of cancer. This review focuses on the immunomodulatory effects of polyphenols in breast cancer, emphasizing their capacity to influence the reaction of adaptive and innate immune cells within the tumor-associated environment. Polyphenols are implicated in the modulation of inflammation, the enhancement of antioxidant defenses, the promotion of epigenetic modifications, and the support of immune functions. Additionally, these compounds have been shown to influence the activity of critical immune cells, including macrophages and T cells. By targeting pathways involved in immune evasion, polyphenols may augment the capacity of the defensive system to detect and eliminate tumors. The findings suggest that incorporating polyphenol-rich foods into the diet could offer a promising, collaborative (integrative) approach to classical breast cancer remedial procedures by regulating how the defense mechanism interacts with the disease.

Impact of Neoadjuvant Therapy on PD-L1 Expression in Triple-Negative Breast Cancer and Correlation with Clinicopathological Factors

BACKGROUND

This study aims to deliver more insights on the impact of neoadjuvant treatment on Pd-L1 expression and to evaluate its correlation with clinicopathological factors.

METHODS

We reviewed 88 TNBC cases for the period 2021-2023. Data on age, tumor size, stage, and treatment were collected. Histological slides were assessed for subtype, grade, and TILs. A total of 48 received neoadjuvant treatment. HER2 and Ki67 were evaluated via immunohistochemistry. PD-L1 expression was tested on primary and residual tumors. Statistical analysis was performed using IBM SPSS (p < 0.05).

RESULTS

In this study, PD-L1 positive expression was found in 44.3% of primary tumors, with 52.9% of initially positive cases losing expression post-treatment. TILs were significantly higher in PD-L1-positive tumors (mean 41.79% vs. 27.55%, p = 0.001). A notable correlation was found between PD-L1 expression and Ki-67 proliferation index, with PD-L1-positive tumors having a median Ki-67 of 64.49 compared to 52.86 in negative cases (p = 0.015). Neoadjuvant immunotherapy led to a lower mean residual cancer burden (0.95 vs. 2.55, p = 0.002) compared to chemotherapy alone. Higher Ki-67 levels (≥50%) were associated with better treatment outcomes, showing a mean RCB score of 1.60 versus 3.16 for lower levels (p = 0.022). HER2-negative cases had a higher prevalence of favorable pathological response (54.5%) compared to HER2-low tumors (25%, p = 0.048), because of the strong correlation to high proliferative index.

CONCLUSIONS

In conclusion, PD-L1 expression in TNBC shows significant discordance post-treatment, highlighting the need for routine testing and further research on predictive biomarkers.

Spatial transcriptomics reveals substantial heterogeneity in triple-negative breast cancer with potential clinical implications

While triple-negative breast cancer (TNBC) is known to be heterogeneous at the genomic and transcriptomic levels, spatial information on tumor organization and cell composition is still lacking. Here, we investigate TNBC tumor architecture including its microenvironment using spatial transcriptomics on a series of 92 patients. We perform an in-depth characterization of tumor and stroma organization and composition using an integrative approach combining histomorphological and spatial transcriptomics. Furthermore, a detailed molecular characterization of tertiary lymphoid structures leads to identify a gene signature strongly associated to disease outcome and response to immunotherapy in several tumor types beyond TNBC. A stepwise clustering analysis identifies nine TNBC spatial archetypes, further validated in external datasets. Several spatial archetypes are associated with disease outcome and characterized by potentially actionable features. In this work, we provide a comprehensive insight into the complexity of TNBC ecosystem with potential clinical relevance, opening avenues for treatment tailoring including immunotherapy.

Immune environment of high-TIL breast cancer: triple negative and hormone receptor positive HER2 negative

This study explores differences in immune cell (IC) composition and spatial distribution between triple-negative breast cancer (TNBC) and hormone receptor-positive, HER2-negative breast cancer (HR + HER2-BC) in high-TIL (≥60%) cases, focusing on PD-L1 status. Using multiplex immunofluorescence on resected tumor tissues from 18 TNBC and 14 HR + HER2-BC cases, we analyzed IC types (CD20, CD8, CD4, FOXP3) and their spatial interactions. TNBC showed a unique IC composition characterized by a higher proportion of CD8 + IC (stroma: 27% vs 17%, p < 0.001; tumor: 54% vs 31%, p < 0.001) and CD4 + FOXP3 + IC (stroma: 3.9% vs 3.0%, p = 0.036), compared to HR + HER2-BC. Notably, PD-L1 positive TNBC cases demonstrated denser infiltration CD4 + FOXP3 + IC in the stromal region compared to HR + HER2-BC (146.4 ± 67.1/mm2 vs 114.3 ± 146.9/mm2, p = 0.036), along with pronounced IC clustering near TC. Both tumor subtypes displayed varied IC compositions based on PD-L1 status. In conclusion, IC composition and spatial distribution in high-TIL TNBC and HR + HER2-BC significantly differ, influenced by PD-L1 status.

Mechanical HIFU and immune checkpoint inhibition: toward clinical implementation

Objective: Immune checkpoint inhibition (ICI) has significantly advanced the field of immuno-oncology, yet not all patients benefit from this therapy. Combining ICI with other therapeutic modalities, including tumor ablation, is currently being explored as a method to enhance ICI efficacy. Mechanical High-Intensity Focused Ultrasound (M-HIFU) represents a promising tumor ablative therapy, inducing cavitation within the tumor, resulting in tumor cell destruction and the release of danger signals and tumor antigens, two key factors contributing to anti-tumor immune responses.

Methods/Results: Preclinical studies on the impact of M-HIFU on the anti-tumor immune response are guiding the translational application of this technique in the clinical setting. This review provides a comprehensive overview of the current understanding of the effects of M-HIFU on the immune system. We report on the effect of M-HIFU on soluble immune modulators and immune cells in different preclinical models, and potential contributions to the anti-tumor immune response. We discuss clinical studies applying M-HIFU and studies that have combined ICI with other ablative therapies to draw parallels to clinical implementation of M-HIFU. Further, we will highlight essential questions that should be addressed in future clinical trials exploring the combination of M-HIFU and ICI in the clinical setting.

Conclusion: Overall, this review offers guidance for the clinical implementation of combining M-HIFU with ICI and highlights key questions that remain to be addressed in first clinical studies.

Breast cancer and cardiovascular health

Modern cancer therapies greatly improve clinical outcomes for both early and advanced breast cancer patients. However, these advances have raised concerns about potential short- and long-term toxicities, including cardiovascular toxicities. Therefore, understanding the common risk factors and underlying pathophysiological mechanisms contributing to cardiovascular toxicity is essential to ensure best breast cancer outcomes. While cardio-oncology has emerged as a sub-speciality to address these challenges, it is essential that all cardiologists recognize and understand the cardiovascular consequences of cancer therapy. This review aims to provide a comprehensive overview of the potential adverse cardiovascular effects associated with modern breast cancer therapies. A preventive, diagnostic, and therapeutic workflow to minimize the impact of cardiovascular toxicity on patient outcomes is presented. Key aspects of this workflow include regular monitoring of cardiovascular function, early detection and management of cancer therapy-related cardiovascular toxicities, and optimization of cardiovascular risk factor control. By highlighting the gaps in knowledge in some areas, this review aims to emphasize the critical role of cardio-oncology research in ensuring the holistic well-being of patients with breast cancer.

Genomic, immunologic, and prognostic associations of TROP2 (TACSTD2) expression in solid tumors

BACKGROUND

TROP2 (TACSTD2) expression is associated with decreased overall survival (OS) in some solid tumors, and the TROP2-targeting antibody-drug conjugate (ADC) sacituzumab govitecan has been approved in breast and urothelial carcinomas. We aimed to explore the multi-omic landscape associated with TACSTD2 gene expression in various solid tumors to identify patients most likely to benefit from this approach.

METHODS

Breast (N = 11 246), colorectal (N = 15 425), hepatocellular (N = 433), pancreatic (N = 5488), and urothelial (N = 4125) tumors were stratified into quartiles by TACSTD2 gene expression, analyzed by next-generation DNA sequencing, whole transcriptome sequencing, and immunohistochemistry at Caris Life Sciences (Phoenix, AZ). Survival data were obtained from insurance claims, and Kaplan-Meier estimates were calculated for molecularly defined cohorts.

RESULTS

Several pathogenic mutations were associated with TACSTD2-high tumors, including TP53 in breast, colorectal (CRC), pancreatic, and hepatocellular cancers; KRAS in pancreatic and CRC cancers; ARID1A and FGFR3 in urothelial cancer; and CTNNB1 in hepatocellular cancer. TACSTD2-low breast tumors were enriched for copy number amplifications in CCND1 and FGF/R family member genes. TACSTD2 high was generally associated with more immune cell infiltration and greater T-cell inflammation scores. Patients with TACSTD2-high breast, CRC, and pancreatic cancers demonstrated a significantly shorter OS than TACSTD2-low tumors. This was restricted to CRC with microsatellite stable tumors and patients with pancreatic cancer with KRAS-mutant tumors. Patients with breast cancer with TACSTD2-high tumors also experienced significantly worse OS following immune checkpoint inhibitors.

CONCLUSIONS

TACSTD2 expression is associated with key driver alterations and a more active immune microenvironment, suggesting possible combinatorial strategies with TROP2-targeting ADCs plus immunotherapy in various solid tumors.

Light-activated hypoxia-sensitive biomimetic decoy efficiently cascading photodynamic-chemo therapy for breast cancer

The hypoxic microenvironment within the tumor microenvironment of breast cancer imposes a challenge in overcoming chemotherapy resistance. In this investigation, we designed a novel strategy utilizing a light-controlled cascade targeting nanomedicine specifically tailored for enhanced immune therapy of breast cancer. Albumin nanoparticle was achieved by crosslinking, followed by loading TPZ and Ce6, and subsequent modification to enable selective binding with CD44 hyaluronic acid to form nanomedicine. Encouragingly, it was demonstrated the remarkable ability of the nanomedicine to effectively internalize into cellular entities, thereby inducing apoptosis in 4T1 cells efficiently in vitro when exposed to light irradiation. In vivo assessments showcased the exceptional aptitude of the nanomedicine not only for preferential accumulation within tumor tissues, but also for substantial suppression of tumor growth. Immune mechanisms have shown that nanomedicine treatment promoted the maturation of DCs in vivo, enhanced the proportion of CD8+ T cells in the spleen and tumor, and simultaneously upregulated the ratio of M1 macrophages favorable for anti-tumor effects. These outcomes collectively advance a fresh perspective for the clinical breast cancer therapy.

Precision medicine in breast cancer (Review)

Precision medicine in breast cancer is a revolutionary approach that customizes diagnosis and treatment based on individual and tumor characteristics, departing from the traditional one-size-fits-all approach. Breast cancer is diverse, with various subtypes driven by distinct genetic mutations. Understanding this diversity is crucial for tailored treatment strategies that target specific vulnerabilities in each tumor. Genetic testing, particularly for mutations in breast cancer gene (BRCA) DNA repair-associated genes, helps assess hereditary risks and influences treatment decisions. Molecular subtyping guides personalized treatments, such as hormonal therapies for receptor-positive tumors and human epidermal growth factor receptor 2 (HER2)-targeted treatments. Targeted therapies, including those for HER2-positive and hormone receptor-positive breast cancers, offer more effective and precise interventions. Immunotherapy, especially checkpoint inhibitors, shows promise, particularly in certain subtypes such as triple-negative breast cancer, with ongoing research aiming to broaden its effectiveness. Integration of big data and artificial intelligence enhances personalized treatment strategies, while liquid biopsies provide real-time insights into tumor dynamics, aiding in treatment monitoring and modification. Challenges persist, including accessibility and tumor complexity, but emerging technologies and precision prevention offer hope for improved outcomes. Ultimately, precision medicine aims to optimize treatment efficacy, minimize adverse effects and enhance the quality of life for patients with breast cancer.

Establishment and verification of a prognostic immune cell signature-based model for breast cancer overall survival

Background

Breast cancer (BRCA) is a prevalent and aggressive disease. Despite various treatments being applied, a significant number of patients continue to experience unfavorable prognoses. Accurate prognosis prediction in BRCA is crucial for tailoring individualized treatment plans and improving patient outcomes. Recent studies have highlighted the significance of immune cell infiltration in the tumor microenvironment (TME), but predicting survival remains challenging due to the heterogeneity of BRCA. The aim of this study was thus to produce an immune cell signature-based framework capable of predicting the prognosis of patients with BRCA.

Methods

The GSE169246 dataset was from the Gene Expression Omnibus (GEO) database, comprising single-cell RNA sequencing (scRNA-seq) data from 95 individuals with BRCA. Seurat, principal component analysis (PCA), the unified matrix polynomial approach (UMAP) algorithm, and linear dimensionality reduction were used to determine the heterogeneity of T cells. Overlapping analysis of differentially expressed genes (DEGs), genes associated with prognosis, and T-cell pharmacodynamics-related genes were used to obtain the T-cell core pharmacodynamics-related genes. The dimensionality of the T-cell core pharmacodynamics-related genes was reduced employing the least absolute shrinkage and selection operator (LASSO) Cox regression model and the LASSO model. The prognostic model was built via a Cox analysis of the overall survival (OS) information. The clinical sample included 95 patients with BRCA who underwent surgical treatment from October 2018 to October 2021 at the Second Affiliated Hospital of Qiqihar Medical University. Patients were divided into a good prognosis group and a poor prognosis group based on their prognostic outcomes. The predictive value of tumor characteristics and immune responses was validated through correlation analysis, logistic regression analysis, and receiver operating characteristic (ROC) analysis.

Results

A group of 95 genes was used to establish a prognostic model. In the GEO clinical sample, with a high-risk group demonstrating shorter median survival times (2,447 vs. 6,498 days, P=4.733e-12). Area under the curve (AUC) values of 0.75, 0.75, and 0.72 were obtained for 2-, 4-, and 6-year OS predictions, respectively. Clinical validation found that the 6-year OS of the favorable prognosis group was significantly higher than that of the unfavorable prognosis group (92.06% vs. 65.62%; P=0.005). Poor prognosis was positively correlated with age, tumor size, B-cell level, and CTLA4 level and negatively correlated with tumor stage (T1/T2), lymph node metastasis stage (N0), clinical stage I-II, CD3+T-cell, CD4+T-cell, CD8+T-cell, neutrophil, lymphocyte, natural kill cell, TIGIT expression and OS. The combined model of clinical parameters had an AUC value of 0.898.

Conclusions

This study established a prognostic model that demonstrated excellent predictive value for OS of BRCA. The predictive model developed offers valuable insights into prognosis and treatment planning, emphasizing the importance of tumor characteristics and immune cell infiltration.

Mesoporous Microneedles Enabled Localized Controllable Delivery of Stimulator of Interferon Gene Agonist Nanoexosomes for FLASH Radioimmunotherapy against Breast Cancer

The immunosuppressive nature of the tumor microenvironment (TME) contributes to radioresistance, thereby impairing the effectiveness of radiotherapy as a therapeutic intervention. Activation through the stimulator of interferon genes (STING) pathway shows potential in modulating immunogenicity. However, the therapeutic efficacy of STING agonists might be restricted by off-target effects and potential cytotoxicity. In this work, nanoexosomes (EXOs) loaded within porous microneedles were employed for precise delivery of the STING agonist MSA-2 (MEM) to the tumor site. Leveraging the enhanced tumor penetration enabled by microneedles, EXOs can be continually released and accumulate within deep residual tumors. Once internalized, these EXOs release the encapsulated MSA-2, facilitating the activation of the STING pathway upon exposure to ultrahigh dose-rate (FLASH) irradiation. This strategy elevates the type I interferon level, promotes dendric cell maturation, and modulates the immunosuppressive TME, showing efficient antitumor efficacy in both primary/metastatic tumors. Furthermore, the induction of a potent immune response effectively prevented tumor recurrence. The combination of EXO-loaded microneedles with FLASH radiotherapy resulted in minimal systemic side effects, attributed to precise drug delivery and radioprotection conferred by FLASH. Altogether, the strategic design of EXO-loaded microneedles holds promise for enhancing MSA-2 delivery, thereby mitigating the radioresistant tumor microenvironment through STING cascade activation-mediated immunotherapy, consequently optimizing the outcomes of FLASH radiotherapy.

The wonders of X-PDT: an advance route to cancer theranostics

Global mortality data indicates cancer as the second-leading cause of death worldwide. Therefore, there's a pressing need to innovate effective treatments to address this significant medical and societal challenge. In recent years, X-ray-induced photodynamic therapy (X-PDT) has emerged as a promising advancement, revolutionizing traditional photodynamic therapy (PDT) for deeply entrenched malignancies by harnessing penetrating X-rays as external stimuli. Recent developments in X-ray photodynamic therapy have shown a trend toward minimizing radiation doses to remarkably low levels after the proof-of-concept demonstration. Early detection and real-time monitoring are crucial aspects of effective cancer treatment. Sophisticated X-ray imaging techniques have been enhanced by the introduction of X-ray luminescence nano-agents, alongside contrast nanomaterials based on X-ray attenuation. X-ray luminescence-based in vivo imaging offers excellent detection sensitivity and superior image quality in deep tissues at a reasonable cost, due to unhindered penetration and unimpeded auto-fluorescence of X-rays. This review emphasizes the significance of X-ray responsive theranostics, exploring their mechanism of action, feasibility, biocompatibility, and promising prospects in imaging-guided therapy for deep-seated tumors. Additionally, it discusses promising applications of X-PDT in treating breast cancer, liver cancer, lung cancer, skin cancer, and colorectal cancer.

Osteopontin is a therapeutic target that drives breast cancer recurrence

Recurrent breast cancers often develop resistance to standard-of-care therapies. Identifying targetable factors contributing to cancer recurrence remains the rate-limiting step in improving long-term outcomes. In this study, we identify tumor cell-derived osteopontin as an autocrine and paracrine driver of tumor recurrence. Osteopontin promotes tumor cell proliferation, recruits macrophages, and synergizes with IL-4 to further polarize them into a pro-tumorigenic state. Macrophage depletion and osteopontin inhibition decrease recurrent tumor growth. Furthermore, targeting osteopontin in primary tumor-bearing female mice prevents metastasis, permits T cell infiltration and activation, and improves anti-PD-1 immunotherapy response. Clinically, osteopontin expression is higher in recurrent metastatic tumors versus female patient-matched primary breast tumors. Osteopontin positively correlates with macrophage infiltration, increases with higher tumor grade, and its elevated pathway activity is associated with poor prognosis and long-term recurrence. Our findings suggest clinical implications and an alternative therapeutic strategy based on osteopontin's multiaxial role in breast cancer progression and recurrence.

Melanin-intercalated layered double hydroxide LDH/MNP as a stable photothermal agent

Melanin nanoparticles (MNPs) are a type of electronegative compound that can be used as photothermal agent for cancer treatment. Nevertheless, the agglomeration of MNP, which is one of the limitations in practice, contributes to the instability of MNP. Pristine layered double hydroxide (LDH), as a kind of positive inorganic material when there exist no other cargo between its layers, can accommodate electronegative molecules between its layers to endow them with stable properties. Hence, in this study, electronegative MNP was intercalated into LDH lamellas via ion-exchange method to obtain the stable original photothermal agent LDH/MNP, solving the tough problem of MNP's agglomeration. The surface morphology, X-ray diffraction and fourier transform infrared spectra affirmed the successful intercalation of MNP between LDH lamellas. The Z-average particle sizes of LDH/MNP on day 0, 7 and 14 were measured as 221.8 nm, 227.6 nm and 230.5 nm without obvious fluctuation, while the particle sizes of MNP went through dramatic enlargement from 105.8 nm (day 0) to 856.1 nm (day 7), indicating the better stability of LDH/MNP than MNP. The typical polymer dispersity index (PDI) values on day 0, 7 and 14 verified the better stability of LDH/MNP, too. Photothermal properties of LDH/MNP were assessed and the results ensured the representative photothermal properties of LDH/MNP. The fine cytocompatibility of LDH/MNP was verified via cytotoxicity test. Results confirmed that the agglomeration of MNP disappeared after its intercalation into LDH and LDH/MNP possessed fine stability as well as typical photothermal property. The intercalation of MNP into LDH gave the photothermal agent MNP a promising way for its better stability and long-term availability in photothermal treatment.

Targeting CD276 for T cell-based immunotherapy of breast cancer

BACKGROUND

Breast cancer (BC) is the most common malignancy in women. Immunotherapy has revolutionized treatment options in many malignancies, and the introduction of immune checkpoint inhibition yielded beneficial results also in BC. However, many BC patients are ineligible for this T cell-based therapy, others do not respond or only briefly. Thus, there remains a high medical need for new therapies, particularly for triple-negative BC. CD276 (B7-H3) is overexpressed in several tumors on both tumor cells and tumor vessels, constituting a promising target for immunotherapy.

METHODS

We analyzed tumor samples of 25 patients using immunohistochemistry to assess CD276 levels. The potential of CC-3, a novel bispecific CD276xCD3 antibody, for BC treatment was evaluated using various functional in vitro assays.

RESULTS

Pronounced expression of CD276 was observed in all analyzed tumor samples including triple negative BC. In analyses with BC cells, CC-3 induced profound T cell activation, proliferation, and T cell memory subset formation. Moreover, treatment with CC-3 induced cytokine secretion and potent tumor cell lysis.

CONCLUSION

Our findings characterize CD276 as promising target and preclinically document the therapeutic potential of CC-3 for BC treatment, providing a strong rationale for evaluation of CC-3 in BC patients in a clinical trial for which the recruitment has recently started.

Gal-3 blocks the binding between PD-1 and pembrolizumab

INTRODUCTION

Immune checkpoint inhibitors (ICI) have revolutionized the treatment of metastatic malignant melanoma (MM) and improved long-term survival. Despite the impressive results, some patients still have progressive disease, and the search for biomarkers predicting response to ICI treatment is ongoing. In this search, galectin-3 (Gal-3) has been suggested as a molecule of interest, both as a marker of treatment response and as a treatment target to potentiate ICI therapy. We have previously demonstrated the binding between programmed cell death 1 (PD-1) and Gal-3, and here, we investigated the interaction between PD-1, pembrolizumab, and Gal-3 in metastatic MM patients.

METHODS

The binding between PD-1, pembrolizumab and Gal-3 was investigated by surface plasmon resonance (SPR) and cryogenic electron microscopy (cryo-EM). The function was studied in in vitro cultures and soluble levels of both PD-1 and Gal-3 were measured in metastatic MM patients, treated with pembrolizumab.

RESULTS

By SPR, we demonstrated that Gal-3 can block the binding between PD-1 and pembrolizumab, and further visualized a steric inhibition using cryo-EM. T cells cultured with Gal-3 had reduced pro-inflammatory cytokine production, which could not be rescued by pembrolizumab. In patients with metastatic MM, high levels of Gal-3 in plasma were found in patients with a longer progression-free survival in the study period, whereas high Gal-3 expression in the tumor was seen in patients with disease progression. Soluble PD-1 levels in plasma increased after treatment with pembrolizumab and correlated with disease progression.

CONCLUSION

We demonstrate that the interaction between PD-1 and Gal-3 interferes with the binding of pembrolizumab, supporting that an immune suppression induced by Gal-3 in the tumor microenvironment cannot be rescued by pembrolizumab.

Human breast tissue engineering in health and disease

The human mammary gland represents a highly organized and dynamic tissue, uniquely characterized by postnatal developmental cycles. During pregnancy and lactation, it undergoes extensive hormone-stimulated architectural remodeling, culminating in the formation of specialized structures for milk production to nourish offspring. Moreover, it carries significant health implications, due to the high prevalence of breast cancer. Therefore, gaining insight into the unique biology of the mammary gland can have implications for managing breast cancer and promoting the well-being of both women and infants. Tissue engineering techniques hold promise to narrow the translational gap between existing breast models and clinical outcomes. Here, we provide an overview of the current landscape of breast tissue engineering, outline key requirements, and the challenges to overcome for achieving more predictive human breast models. We propose methods to validate breast function and highlight preclinical applications for improved understanding and targeting of breast cancer. Beyond mammary gland physiology, representative human breast models can offer new insight into stem cell biology and developmental processes that could extend to other organs and clinical contexts.

Role of Immunotherapy in Conjunction With the Surgical Treatment of Breast Cancer: Preoperative and Postoperative Applications

Breast cancer is one of the most common cancers in the world. Since the appearance of molecular medicine, the perspective of breast cancer treatment has changed, making it more successful in comparison with the treatment during previous years. Numerous ongoing trials are exploring the capacity of immunotherapy, mainly in immune checkpoint inhibitors (ICIs), in conjunction with conventional therapies or with antibody-drug conjugates (ADCs). The current narrative review discusses the advantages and limitations of immunotherapy in breast cancer treatment in conjunction with the surgical options available. Going through the modern capacity of surgery treatment and how the use of immunotherapy in conjunction with it has emerged as a transformative approach to breast cancer and listing the main complications and adverse effects caused by ICIs. We searched Google Scholar, PubMed, MEDLINE, and EMBASS. Fourteen different articles showed that the use of cytokines and cancer vaccines revealed new possibilities to treat breast cancer with antibodies against PD-1/PD-L1 (pembrolizumab), PI3K/Akt/mTOR (alpelisib and everolimus), CAR T-cell (chimeric antigen receptor), PARP (poly ADP-ribose polymerase), and CTLA4 (cytotoxic T-lymphocyte-associated protein 4), and with representative relevance of changing in tumor microenvironment. Immunotherapy made it possible to reduce recurrences, after radiotherapy and surgery. Estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) targets show also a high effectivity. In recent years, the release of new strategies has become promising, for changing the microenvironment and de-escalation of therapy based on tumor biology, novel biomarkers, and tumor spread.

Breast cancer immunotherapy: Realities and advances

Breast cancer (BC) is the most common malignant tumor and the main cause of death in women worldwide. With increased knowledge regarding tumor escape mechanisms and advances in immunology, many new antitumor strategies such as nonspecific immunotherapies, monoclonal antibodies, anticancer vaccines, and oncolytic viruses, among others, make immunotherapy a promising approach for the treatment of BC. However, these approaches still require meticulous assessment and readjustment as resistance and modest response rates remain important barriers. In this article, we aim to summarize the most recent data available in BC immunotherapy to include the results of ongoing clinical trials and approved therapies used as monotherapies or in combination with conventional treatments.

Multifunctional Biomimetic Liposomes with Improved Tumor-Targeting for TNBC Treatment by Combination of Chemotherapy, Antiangiogenesis and Immunotherapy

Triple negative breast cancer (TNBC) featuring high relapses and metastasis shows limited clinical therapeutic efficiency with chemotherapy for the extremely complex tumor microenvironment, especially angiogenesis and immunosuppression. Combination of antiangiogenesis and immunotherapy holds promise for effective inhibition of tumor proliferation and invasion, while it remains challenging for specific targeting drug delivery to tumors and metastatic lesions. Here, a multifunctional biomimetic liposome loading Gambogic acid (G/R-MLP) is developed using Ginsenoside Rg3 (Rg3) to substitute cholesterol and cancer cell membrane coating, which is designed to increase long-circulating action by a low immunogenicity and specifically deliver gambogic acid (GA) to tumor site and metastatic lesions by homologous targeting and glucose transporter targeting. After G/R-MLP accumulates in the primary tumors and metastatic nodules, it synergistically enhances the antitumor efficacy of GA, effectively suppressing the tumor growth and lung metastasis by killing tumor cells, inhibiting tumor cell migration and invasion, achieving antiangiogenesis and improving the antitumor immunity. All in all, the strategy combining chemotherapy, antiangiogenesis, and immunotherapy improves therapeutic efficiency and prolonged survival, providing a new perspective for the clinical treatment of TNBC.

Tertiary lymphoid structures' pattern and prognostic value in primary adenocarcinoma of jejunum and ileum

To date, there have been no reports on tertiary lymphoid structures (TLS) in primary adenocarcinoma of jejunum and ileum. In this study, we employed digital pathology image analysis software to classify and quantify TLS, and evaluated the maturity of TLS using immunohistochemistry. Molecular genetics and immunotherapy biomarker detection were performed using next-generation sequencing technology, such as tumor mutational burden (TMB) and microsatellite instability (MSI). The aim of this study was to investigate the presence, location, maturity, association with immunotherapy biomarkers, and prognostic value of TLS in primary adenocarcinoma of jejunum and ileum. Compared to secondary follicle-like TLS (SFL-TLS), intra-tumoral TLS (IT-TLS) were more likely to manifest as early TLS (E-TLS) (P = 0.007). Compared to IT-TLS, SFL-TLS had a higher propensity to occur at the invasive margin (IM) (P = 0.032) and showed a trend towards being more prevalent at the tumor periphery (P = 0.057). In terms of immunotherapy biomarkers, there was a higher trend of IM-TLS density in PD-L1(22C3) score CPS < 1 group compared to PD-L1(22C3) score CPS ≥ 1 group (P = 0.071). TMB-H was significantly associated with MSI-H (P = 0.040). Univariate survival analysis demonstrated a correlation between high SFL-TLS group and prolonged disease free survival (DFS) (P = 0.047). There was also a trend towards prolonged DFS in the E-TLS-high group compared to the E-TLS-low group (P = 0.069). The peri-tumoral TLS (PT-TLS)-high group showed a trend of prolonged overall survival (OS) compared to the PT-TLS-low group (P = 0.090). In conclusion, the majority of TLS were located at the invasive margin and tumor periphery, predominantly consisting of mature TLS, while IT-TLS were mainly immature. Notably, TMB was closely associated with MSI and PD-L1, indicating potential predictive value for immunotherapy in primary adenocarcinoma of jejunum and ileum.

STING-Activating Polymer-Drug Conjugates for Cancer Immunotherapy

The stimulator of interferon genes (STING) pathway links innate and adaptive antitumor immunity and therefore plays an important role in cancer immune surveillance. This has prompted widespread development of STING agonists for cancer immunotherapy, but pharmacological barriers continue to limit the clinical impact of STING agonists and motivate the development of drug delivery systems to improve their efficacy and/or safety. We developed SAPCon, a STING-activating polymer-drug conjugate platform based on strain-promoted azide-alkyne cycloaddition of a novel dimeric amidobenzimidazole (diABZI) STING prodrug to hydrophilic poly(dimethylacrylamide-co-azido-ethylmethacrylate) polymer chains through a cathepsin B-responsive linker to increase circulation time and enable passive tumor accumulation. We found that intravenously administered SAPCon accumulated at tumor sites, where it was endocytosed by tumor-associated myeloid cells, resulting in increased STING activation in the tumor tissue. Consequently, SAPCon promoted an immunogenic tumor microenvironment characterized by increased frequency of activated macrophages and dendritic cells and improved infiltration of CD8+ T cells, resulting in inhibition of tumor growth, prolonged survival, and enhanced response to anti-PD-1 immune checkpoint blockade in orthotopic breast cancer models. Collectively, these studies position SAPCon as a modular and programmable platform for improving the efficacy of systemically administered STING agonists for cancer immunotherapy.

A Preliminary Analysis of Circulating Tumor Microemboli from Breast Cancer Patients during Follow-Up Visits

BACKGROUND

Most breast cancer-related deaths are caused by distant metastases and drug resistance. It is important to find appropriate biomarkers to monitor the disease and to predict patient responses after treatment early and accurately. Many studies have found that clustered circulating tumor cells, with more correlations with metastatic cancer and poor survival of patients than individual ones, are promising biomarkers.

METHODS

Eighty samples from eleven patients with breast cancer during follow-up visits were examined. By using a microfluidic chip and imaging system, the number of circulating tumor cells and microemboli (CTC/CTM) were counted to assess the distribution in stratified patients and the potential in predicting the disease condition of patients after treatments during follow-up visits. Specific components and subtypes of CTM were also preliminarily investigated.

RESULTS

Compared to CTC, CTM displayed a distinguishable distribution in stratified patients, having a better AUC value, in predicting the disease progression of breast cancer patients during follow-up visits in this study. Four subtypes were categorized from the identified CTM by considering different components. In combination with CEA and CA153, enumerated CTC and CTM from individual patients were applied to monitor the disease condition and patient response to the therapy during follow-up visits.

CONCLUSIONS

The CTM and its subtypes are promising biomarkers and valuable tools for studying cancer metastasis and longitudinally monitoring cancer patients during follow-up visits.

Characterizing the Tumor Microenvironment and Its Prognostic Impact in Breast Cancer

The tumor microenvironment (TME) is crucial in cancer development and therapeutic response. Immunotherapy is increasingly recognized as a critical component of cancer treatment. While immunotherapies have shown efficacy in various cancers, including breast cancer, patient responses vary widely. Some patients receive significant benefits, while others experience minimal or no improvement. This disparity underscores the complexity and diversity of the immune system. In this study, we investigated the immune landscape and cell-cell communication within the TME of breast cancer through integrated analysis of bulk and single-cell RNA sequencing data. We established profiles of tumor immune infiltration that span across a broad spectrum of adaptive and innate immune cells. Our clustering analysis of immune infiltration identified three distinct patient groups: high T cell abundance, moderate infiltration, and low infiltration. Patients with low immune infiltration exhibited the poorest survival rates, while those in the moderate infiltration group showed better outcomes than those with high T cell abundance. Moreover, the high cell abundance group was associated with a greater tumor burden and higher rates of TP53 mutations, whereas the moderate infiltration group was characterized by a lower tumor burden and elevated PIK3CA mutations. Analysis of an independent single-cell RNA-seq breast cancer dataset confirmed the presence of similar infiltration patterns. Further investigation into ligand-receptor interactions within the TME unveiled significant variations in cell-cell communication patterns among these groups. Notably, we found that the signaling pathways SPP1 and EGF were exclusively active in the low immune infiltration group, suggesting their involvement in immune suppression. This work comprehensively characterizes the composition and dynamic interplay in the breast cancer TME. Our findings reveal associations between the extent of immune infiltration and clinical outcomes, providing valuable prognostic information for patient stratification. The unique mutations and signaling pathways associated with different patient groups offer insights into the mechanisms underlying diverse tumor immune infiltration and the formation of an immunosuppressive tumor microenvironment.

An Abscopal Effect on Lung Metastases in Canine Mammary Cancer Patients Induced by Neoadjuvant Intratumoral Immunotherapy with Cowpea Mosaic Virus Nanoparticles and Anti-Canine PD-1

Neoadjuvant intratumoral (IT) therapy could amplify the weak responses to checkpoint blockade therapy observed in breast cancer (BC). In this study, we administered neoadjuvant IT anti-canine PD-1 therapy (IT acPD-1) alone or combined with IT cowpea mosaic virus therapy (IT CPMV/acPD-1) to companion dogs diagnosed with canine mammary cancer (CMC), a spontaneous tumor resembling human BC. CMC patients treated weekly with acPD-1 (n = 3) or CPMV/acPD-1 (n = 3) for four weeks or with CPMV/acPD-1 (n = 3 patients not candidates for surgery) for up to 11 weeks did not experience immune-related adverse events. We found that acPD-1 and CPMV/acPD-1 injections resulted in tumor control and a reduction in injected tumors in all patients and in noninjected tumors located in the ipsilateral and contralateral mammary chains of treated dogs. In two metastatic CMC patients, CPMV/acPD-1 treatments resulted in the control and reduction of established lung metastases. CPMV/acPD-1 treatments were associated with altered gene expression related to TLR1-4 signaling and complement pathways. These novel therapies could be effective for CMC patients. Owing to the extensive similarities between CMC and human BC, IT CPMV combined with approved anti-PD-1 therapies could be a novel and effective immunotherapy to treat local BC and suppress metastatic BC.

Myeloid‑derived suppressor cells as targets of emerging therapies and nanotherapies (Review)

Breast cancer (BC) is the leading cause of cancer-related mortality among women worldwide. Immunotherapies are a promising approach in cancer treatment, particularly for aggressive forms of BC with high mortality rates. However, the current eligibility for immunotherapy remains limited to a limited fraction of patients with BC. Myeloid-derived suppressor cells (MDSCs), originating from myeloid cells, are known for their dual role in immunosuppression and tumor promotion, significantly affecting patient outcomes by fostering the formation of premetastatic niches. Consequently, targeting MDSCs has emerged as a promising avenue for further exploration in therapeutic interventions. Leveraging nanotechnology-based drug delivery systems, which excel in accumulating drugs within tumors via passive or active targeting mechanisms, are a promising strategy for the use of MDSCs in the treatment of BC. The present review discusses the immunosuppressive functions of MDSCs, their role in BC, and the diverse strategies for targeting them in cancer therapy. Additionally, the present review discusses future advancements in BC treatments focusing on MDSCs. Furthermore, it elucidates the mechanisms underlying MDSC activation, recruitment and differentiation in BC progression, highlighting the clinical characteristics that render MDSCs suitable candidates for the therapy and targeted nanotherapy of BC.

Protein biomarkers for subtyping breast cancer and implications for future research: a 2024 update

INTRODUCTION

Breast cancer subtyping is used clinically for diagnosis, prognosis, and treatment decisions. Subtypes are categorized by cell of origin, histomorphology, gene expression signatures, hormone receptor status, and/or protein levels. Categorizing breast cancer based on gene expression signatures aids in assessing a patient's recurrence risk. Protein biomarkers, on the other hand, provide functional data for selecting therapies for primary and recurrent tumors. We provide an update on protein biomarkers in breast cancer subtypes and their application in prognosis and therapy selection.

AREAS COVERED

Protein pathways in breast cancer subtypes are reviewed in the context of current protein-targeted treatment options. PubMed, Science Direct, Scopus, and Cochrane Library were searched for relevant studies between 2017 and 17 August 2024.

EXPERT OPINION

Post-translationally modified proteins and their unmodified counterparts have become clinically useful biomarkers for defining breast cancer subtypes from a therapy perspective. Tissue heterogeneity influences treatment outcomes and disease recurrence. Spatial profiling has revealed complex cellular subpopulations within the breast tumor microenvironment. Deciphering the functional relationships between and within tumor clonal cell populations will further aid in defining breast cancer subtypes and create new treatment paradigms for recurrent, drug resistant, and metastatic disease.

Comparison of water- vs. land-based exercise for improving functional capacity and quality of life in patients living with and beyond breast cancer (the AQUA-FiT study): a randomized controlled trial

BACKGROUND

Patients living with and beyond breast cancer frequently exhibit several side effects that can impact quality of life and physical functioning way beyond diagnosis and cancer therapies. Traditional on-land exercise has shown to be effective in reducing several symptoms of BC but little is known about the role of water-based exercise in improving physical and psychological well-being.

OBJECTIVES

To compare land- vs. water-based exercise training for BC survivors to improve Health-Related Quality of Life (HRQoL), cancer-related fatigue (CRF), physical functioning, body composition and physical activity in patients with BC.

METHODS

A randomised, parallel group (1:1) controlled trial was conducted between 2020 and 2022. Patients were randomly allocated to complete a similar exercise training twice weekly during 12 weeks either on land (LG) using traditional gym equipment or in a swimming pool (WG) using body-weight exercises and water-suitable accessories. Both groups were supervised and monitored by an experienced physiotherapist. Main outcome was HRQoL (EORTC QLQ C30 and B23 module) and CRF measured with the Piper Scale. Secondary variables included functional capacity with the 6 Minutes Walking Test (6MWT), upper and lower body strength (handgrip strength and 30″ Sit-to-Stand (STS) test), body composition and objectively measured physical activity.

RESULTS

28 patients were assessed and randomised during the study period. One patient did not receive the allocated intervention due to skin issues and one patient was dropped out during the intervention. A significant effect of time was found for both symptom severity (F(2,52) = 6.46, p = 0.003) and overall functioning (F1.67,43.45 = 5.215, p =0 .013) but no interaction was found between group and time. No effects were reported for CRF. Similar findings were reported for functional capacity (time effect F1.231,32.019 = 16.818, p < 0.001) and lower body strength (time effect F2,52 = 15.120, p < 0.001) as well as fat mass (time effect F2,52 = 4.38, p = 0.017). Notably, a significant time per group interaction was reported for physical activity (F2,52 = 6.349, p =0.003) with patients in the WG significantly improving PA levels over time while patients in the LG exhibited a marked decreased.

CONCLUSIONS

Exercise training either in water or on land can decrease symptom severity and improve functionality and body composition. Water-based training seems more effecting than land-based exercise to improve physical activity patterns over time.

Metronomic chemotherapy plus anti-PD-1 in metastatic breast cancer: a Bayesian adaptive randomized phase 2 trial

It remains unclear whether metronomic chemotherapy is superior to conventional chemotherapy when combined with immune checkpoint blockade. Here we performed a phase 2 clinical trial of metronomic chemotherapy combined with PD-1 blockade to compare the efficacy of combined conventional chemotherapy and PD-1 blockade using Bayesian adaptive randomization and efficacy monitoring. Eligible patients had metastatic HER2-negative breast cancer and had not received more than one prior line of standard chemotherapy. Patients (total n = 97) were randomized to receive (1) metronomic vinorelbine (NVB) monotherapy (n = 11), (2) NVB plus anti-PD-1 toripalimab (n = 7), (3) anti-angiogenic bevacizumab, NVB and toripalimab (n = 27), (4) conventional cisplatin, NVB and toripalimab (n = 26), or (5) metronomic cyclophosphamide, capecitabine, NVB and toripalimab (the VEX cohort) (n = 26). The primary endpoint was disease control rate (DCR). Secondary objectives included progression-free survival (PFS) and safety. The study met the primary endpoint. The VEX (69.7%) and cisplatin (73.7%) cohorts had the highest DCR. The median PFS of patients in the VEX cohort was the longest, reaching 6.6 months, followed by the bevacizumab (4.0 months) and cisplatin (3.5 months) cohorts. In general, the five regimens were well tolerated, with nausea and neutropenia being the most common adverse events. An exploratory mass cytometry analysis indicated that metronomic VEX chemotherapy reprograms the systemic immune response. Together, the clinical and translational data of this study indicate that metronomic VEX chemotherapy combined with PD-1 blockade can be a treatment option in patients with breast cancer. ClinicalTrials.gov Identifier: NCT04389073 .

Combining luteolin and curcumin synergistically suppresses triple-negative breast cancer by regulating IFN and TGF-β signaling pathways

Combining two or more chemicals in chemotherapy is rapidly increasing because of its higher efficacy, lower toxicity, lower dosages, and lower drug resistance. Here, we identified a novel combination of luteolin (LUT) and curcumin (CUR), two bioactive compounds from foods, synergistically suppressed triple-negative breast cancer (TNBC) cell proliferation (LUT 30 µM + CUR 20 µM), colony formation (LUT 1 µM + CUR 2 µM), and tumor growth in xenograft mice (LUT 10 mg/kg body weight/day + CUR 20 mg/kg body weight/day, i.p. injection every other day, 5 weeks), while the individual chemical alone did not show these inhibitory effects significantly at the selected concentrations/dosages. Our total RNA transcriptome analysis in xenograft tumors revealed that combining LUT and CUR synergistically activated type I interferon (IFN) signaling and suppressed transforming growth factor-beta (TGF-β) signaling pathways, which was further confirmed by the expression/activity of several proteins of the pathways in tumors. In addition, this combination of LUT and CUR also synergistically decreased oncoprotein levels of c-Myc and Notch1, the critical molecules required to maintain stem cell properties, tumor clonal evolution, and drug resistance. These results suggest that the combination of LUT and CUR synergistically inhibits TNBC by suppressing multiple cellular mechanisms, such as proliferation, colony formation, and transformation, as well as tumor migration, invasion, and metastasis, via regulating IFN and TGF-β signaling pathways. Therefore, combining LUT and CUR may be an effective therapeutic agent to treat highly aggressive, drug-resistant TNBC patients after clinical trials.

Hypoxia-induced epigenetic regulation of breast cancer progression and the tumour microenvironment

The events that control breast cancer progression and metastasis are complex and intertwined. Hypoxia plays a key role both in oncogenic transformation and in fueling the metastatic potential of breast cancer cells. Here we review the impact of hypoxia on epigenetic regulation of breast cancer, by interfering with multiple aspects of the tumour microenvironment. The co-dependent relationship between oxygen depletion and metabolic shift to aerobic glycolysis impacts on a range of enzymes and metabolites available in the cell, promoting posttranslational modifications of histones and chromatin, and changing the gene expression landscape to facilitate tumour development. Hormone signalling, particularly through ERα, is also tightly regulated by hypoxic exposure, with HIF-1α expression being a prognostic marker for therapeutic resistance in ER+ breast cancers. This highlights the strong need to understand the hypoxia-endocrine signalling axis and exploit it as a therapeutic target. Furthermore, hypoxia has been shown to enhance metastasis in TNBC cells, as well as promoting resistance to taxanes, radiotherapy and even immunotherapy through microRNA regulation and changes in histone packaging. Finally, several other mediators of the hypoxic response are discussed. We highlight a link between ionic dysregulation and hypoxia signalling, indicating a potential connection between HIF-1α and tumoural Na+ accumulation which would be worth further exploration; we present the role of Ca2+ in mediating hypoxic adaptation via chromatin remodelling, transcription factor recruitment and changes in signalling pathways; and we briefly summarise some of the findings regarding vesicle secretion and paracrine induced epigenetic reprogramming upon hypoxic exposure in breast cancer. By summarising these observations, this article highlights the heterogeneity of breast cancers, presenting a series of pathways with potential for therapeutic applications.

Prognostic and clinicopathological significance of fibrinogen-to-albumin ratio (FAR) in patients with breast cancer: a meta-analysis

BACKGROUND

The fibrinogen-to-albumin ratio (FAR) has been extensively studied for its role in predicting the prognosis of breast cancer (BC) patients; however, existing findings are conflicting. Therefore, this meta-analysis was conducted to identify the significance of FAR in predicting BC prognosis.

METHODS

We searched PubMed, Embase, Web of Science, Cochrane Library, and China National Knowledge Infrastructure databases until May 25, 2024. The value of FAR for predicting overall survival (OS) and disease-free survival (DFS) in BC was examined by calculating the combined hazard ratios (HRs) and 95% confidence intervals (CIs). Correlations between FAR and clinicopathological factors were analyzed using combined odds ratios (ORs) and 95% CIs.

RESULTS

Eight studies involving 4094 patients were included in this work. As shown by our combined data, increased FAR significantly predicted poor OS (HR = 2.84, 95% CI = 1.83-4.39, p < 0.001) and poor DFS (HR = 2.43, 95% CI = 1.66-3.58, p < 0.001) of BC. Moreover, the combined data showed that increased FAR was significantly correlated with age ≥ 50 years (OR = 2.04, 95% CI = 1.37-3.04, p < 0.001), stage III cancer (OR = 1.53, 95% CI = 1.04-2.27, p = 0.033), and the presence of lymph node metastases (OR = 1.33, 95% CI = 1.11-1.61, p = 0.002). Nonetheless, FAR was not significantly associated with tumor size, ER/PR/HER-2 status, or lymphovascular invasion in patients with BC.

CONCLUSION

In this meta-analysis, higher FAR was significantly associated with unfavorable OS and DFS in patients with BC and significantly correlated with several features predictive of cancer development in BC.

Prognostic Value of Fas/Fas Ligand Expression on Circulating Tumor Cells (CTCs) and Immune Cells in the Peripheral Blood of Patients with Metastatic Breast Cancer

The Fas/Fas ligand (FasL) system is a major apoptosis-regulating pathway with a key role in tumor immune surveillance and metastasis. The expression of Fas/FasL on mammary tumor tissues holds prognostic value for breast cancer (BC) patients. We herein assessed Fas/FasL expression on circulating tumor cells (CTCs) and matched peripheral blood mononuclear cells (PBMCs) from 98 patients with metastatic BC receiving first-line treatment. Fas+, FasL+, and Fas+/FasL+ CTCs were identified in 88.5%, 92.3%, and 84.6% of CTC-positive patients, respectively. In addition, Fas+/FasL+, Fas-/FasL+, and Fas-/FasL- PBMCs were identified in 70.3%, 24.2%, and 5.5% of patients, respectively. A reduced progression-free survival (PFS) was revealed among CTC-positive patients (median PFS: 9.5 versus 13.4 months; p = 0.004), and specifically among those harboring Fas+/FasL+ CTCs (median PFS: 9.5 vs. 13.4 months; p = 0.009). On the other hand, an increased overall survival (OS) was demonstrated among patients with Fas+/FasL+ PBMCs rather than those with Fas-/FasL+ and Fas-/FasL- PBMCs (median OS: 35.7 vs. 25.9 vs. 14.4 months, respectively; p = 0.008). These data provide for the first time evidence on Fas/FasL expression on CTCs and PBMCs with significant prognostic value for patients with metastatic BC, thus highlighting the role of the Fas/FasL system in the peripheral immune response and metastatic progression of BC.

Advancements in Understanding the Hide-and-Seek Strategy of Hibernating Breast Cancer Cells and Their Implications in Oncology from a Broader Perspective: A Comprehensive Overview

Despite recent advancements in technology, breast cancer still poses a significant threat, often resulting in fatal consequences. While early detection and treatments have shown some promise, many breast cancer patients continue to struggle with the persistent fear of the disease returning. This fear is valid, as breast cancer cells can lay dormant for years before remerging, evading traditional treatments like a game of hide and seek. The biology of these dormant breast cancer cells presents a crucial yet poorly understood challenge in clinical settings. In this review, we aim to explore the mysterious world of dormant breast cancer cells and their significant impact on patient outcomes and prognosis. We shed light on the elusive role of the G9a enzyme and many other epigenetic factors in breast cancer recurrence, highlighting its potential as a target for eliminating dormant cancer cells and preventing disease relapse. Through this comprehensive review, we not only emphasise the urgency of unravelling the dynamics of dormant breast cancer cells to improve patient outcomes and advance personalised oncology but also provide a guide for fellow researchers. By clearly outlining the clinical and research gaps surrounding dormant breast cancer cells from a molecular perspective, we aim to inspire further exploration of this critical area, ultimately leading to improved patient care and treatment strategies.

Advancements in Immunotherapy for Breast Cancer: Mechanisms, Efficacy, and Future Directions

Breast cancer is a major global health challenge characterized by its diverse biological behavior and varying treatment responses. Traditional therapies, including surgery, radiation, chemotherapy, hormonal therapy, and targeted therapy, have significantly advanced breast cancer treatment but are often limited by issues such as resistance, side effects, and variable efficacy. Immunotherapy has emerged as a transformative approach, leveraging the body's immune system to target and eliminate cancer cells. This review provides a comprehensive overview of recent advancements in immunotherapy for breast cancer, detailing the mechanisms of various therapeutic strategies, including checkpoint inhibitors, monoclonal antibodies, cancer vaccines, adoptive cell therapy, and oncolytic virus therapy. We evaluate the efficacy of these approaches in different stages of breast cancer, highlighting successes and challenges encountered in clinical settings. The review also addresses the current limitations of immunotherapy, such as treatment-related adverse effects, resistance mechanisms, and issues of cost and accessibility. We discuss promising future directions, including emerging targets, combination therapies, and personalized medicine approaches. By integrating recent research and clinical trial data, this review aims to elucidate the potential of immunotherapy to revolutionize breast cancer treatment, offering insights into its future role in improving patient outcomes and shaping the landscape of oncological care.

Dissecting the tumor microenvironment in response to immune checkpoint inhibitors via single-cell and spatial transcriptomics

Cancer is a disease that undergoes selective pressure to evolve during its progression, becoming increasingly heterogeneous. Tumoral heterogeneity can dictate therapeutic response. Transcriptomics can be used to uncover complexities in cancer and reveal phenotypic heterogeneity that affects disease response. This is especially pertinent in the immune microenvironment, which contains diverse populations of immune cells, and whose dynamic properties influence disease response. The recent development of immunotherapies has revolutionized cancer therapy, with response rates of up to 50% within certain cancers. However, despite advances in immune checkpoint blockade specifically, there remains a significant population of non-responders to these treatments. Transcriptomics can be used to profile immune and other cell populations following immune-checkpoint inhibitor (ICI) treatment, generate predictive biomarkers of resistance or response, assess immune effector function, and identify potential immune checkpoints. Single-cell RNA sequencing has offered insight into mRNA expression within the complex and heterogeneous tumor microenvironment at single-cell resolution. Spatial transcriptomics has enabled measurement of mRNA expression while adding locational context. Here, we review single-cell sequencing and spatial transcriptomic research investigating ICI response within a variety of cancer microenvironments.

Understanding tissue-resident macrophages unlocks the potential for novel combinatorial strategies in breast cancer

Tissue-resident macrophages (TRMs) are an integral part of the innate immune system, but their biology is not well understood in the context of cancer. Distinctive resident macrophage populations are identified in different organs in mice using fate mapping studies. They develop from the yolk sac and self-maintain themselves lifelong in specific tissular niches. Similarly, breast-resident macrophages are part of the mammary gland microenvironment. They reside in the breast adipose tissue stroma and close to the ductal epithelium and help in morphogenesis. In breast cancer, TRMs may promote disease progression and metastasis; however, precise mechanisms have not been elucidated. TRMs interact intimately with recruited macrophages, cytotoxic T cells, and other immune cells along with cancer cells, deciding further immunosuppressive or cytotoxic pathways. Moreover, triple-negative breast cancer (TNBC), which is generally associated with poor outcomes, can harbor specific TRM phenotypes. The influence of TRMs on adipose tissue stroma of the mammary gland also contributes to tumor progression. The complex crosstalk between TRMs with T cells, stroma, and breast cancer cells can establish a cascade of downstream events, understanding which can offer new insight for drug discovery and upcoming treatment choices. This review aims to acknowledge the previous research done in this regard while exploring existing research gaps and the future therapeutic potential of TRMs as a combination or single agent in breast cancer.

Assessing risks and knowledge gaps on the impact of systemic therapies in early breast cancer on female fertility: A systematic review of the literature

The therapeutic landscape for early breast cancer (eBC) has expanded by introducing novel anticancer agents into clinical practice. During their reproductive years, women with eBC should be informed of the potential risk of premature ovarian insufficiency (POI) and infertility with the proposed systemic therapy. Although the topic of female fertility is becoming increasingly relevant in patients with cancer, limited information is available on the gonadotoxicity of new agents available for eBC treatment. Analyses from clinical trials and prospective data on ovarian function biomarkers are lacking. The purpose of this systematic review is to report the available preclinical and clinical data on female fertility risk with the use of the new agents that are part of clinical practice use or under development for eBC management. This review highlights the clear need to perform additional research efforts to improve our understanding on the gonoadtoxicity of new anticancer agents.

Chronic Use of Abemaciclib Leading to Breathlessness and Demise: A Case Report

Checkpoint inhibitor pneumonitis (CIP) is a potentially fatal disease that can occur at any duration of treatment. Patients may present with vague respiratory symptoms such as progressive cough, dyspnea, and decreased activity tolerance. Among checkpoint inhibitors, CIP is higher in programmed death 1 (PD-1) inhibitors. An 82-year-old Latina woman with estrogen receptor (ER)-positive human epidermal growth factor receptor (HER)-2-negative lobular carcinoma of the right breast had been treated by partial mastectomy followed by adjuvant hormonal treatment and radiation in 2014. Then CMF (cyclophosphamide, methotrexate, and 5-fluorouracil) was followed by letrozole and abemaciclib, PD-1, therapy in 2022. In 2023, the patient presented with a dry cough and worsening dyspnea with a new oxygen requirement. She was admitted to the hospital with a diagnosis of multifocal pneumonia and sepsis. She unfortunately developed rapidly higher oxygen requirements and acute respiratory distress syndrome (ARDS) and was ultimately presumed to have CIP. She was intubated on hospital day 6 and extubated on day 12 with no plans for reintubation and do-not-resuscitate status. She subsequently had demise after a period of respiratory arrest. CIP is rare but associated with fatal outcomes, especially with the development of ARDS. It is important, along the course of cancer treatment and goals of care discussion, to educate patients and their families on possible side effects of chemotherapy and involve specialists early with the goal of lowering mortality rates. Most patients do not survive this unfortunate progression of disease.