Long-term Clinical Outcomes and Biomarker Analyses of Atezolizumab Therapy for Patients With Metastatic Triple-Negative Breast Cancer: A Phase 1 Study

Fundamental knowledge and research regarding the role of immunity in triple-negative breast cancer from 2014-2024: A bibliometric analysis

Immunity has vital research value and promising applications in triple-negative breast cancer (TNBC). Nevertheless, few bibliometric analyses have systematically investigated this area. This study aimed to comprehensively review the collaboration and impact of countries, institutions, authors, and journals on the role of immunity in TNBC from a bibliometric perspective, evaluate the keyword co-occurrence of the knowledge structure, and identify hot trends and emerging topics. Articles and reviews related to immunity in TNBC were retrieved from the Web of Science core collection using subject search. A bibliometric study was conducted primarily using CiteSpace and VOSviewer. A total of 3,104 articles and reviews were included from January 1, 2014, through December 31, 2024. The number of articles on immunization in TNBC is rising. These publications are mainly from 415 institutions in 82 countries, led by China and the USA. Among these publications, Lajos Pusztai published the most papers, while Peter Schmid was co-cited the most. The most productive journals focused on molecular biology, biological immunology, and clinical medicine. Furthermore, co-citation analysis revealed that tumor microenvironment, biomarkers, and immune checkpoint inhibitors are current and developing research areas. The keywords "immunotherapy" and "nanoparticles" are also likely to be new trends and focal points for future research. This study adopted bibliometric and visualization methods to provide a comprehensive review of the research on immunization in TNBC. This article will help researchers better understand the dynamic evolution of the role of immunity in TNBC and identify areas for future research.

Immunotherapy in breast cancer: current landscape and emerging trends

Breast cancer remains one of the most prevalent malignancies worldwide, underscoring an urgent need for innovative therapeutic strategies. Immunotherapy has emerged as a transformative frontier in this context. In triple-negative breast cancer (TNBC), the combination of immunotherapy based on PD-1/PD-L1 immune checkpoint inhibitors (ICIs) with chemotherapy has proven efficacious in both early and advanced clinical trials. These encouraging results have led to the approval of ICIs for TNBC, opening up new therapeutic avenues for challenging-to-treat patient populations. Furthermore, a multitude of ongoing trials are actively investigating the efficacy of immunotherapy-based combinations, including ICIs in conjunction with chemotherapy, targeted therapy and radiation therapy, as well as other novel strategies such as bispecific antibodies, CAR-T cells and cancer vaccines across all breast cancer subtypes, including HR-positive/HER2-negative and HER2-positive disease. This review provides a comprehensive overview of current immunotherapeutic approaches in breast cancer, highlighting pivotal findings from recent clinical trials and the potential impact of these advancements on patient outcomes.

Phase 2 trial of imprime and pembrolizumab immunotherapy in metastatic triple negative breast cancer patients who have progressed beyond first line chemotherapy

The Phase 2 IMPRIME 1 study evaluated the combination of the pathogen-associated molecular pattern (PAMP) Imprime with the immune checkpoint inhibitor (ICI) pembrolizumab as second or later line of treatment (2 L+) for patients with metastatic triple-negative breast cancer (mTNBC). Eligible patients with mTNBC received weekly Imprime (4 mg/kg) intravenously in combination with pembrolizumab (200 mg every 3 weeks). Primary endpoints were overall response rate (ORR) and safety. Secondary endpoints included disease control rate (DCR), duration of response (DoR), progression free survival (PFS), and overall survival (OS). Exploratory endpoints included correlations between immune cell activation markers in tumor tissues and blood and response to therapy. Of the 42 evaluable patients, six had a response (one complete, five partial), with an ORR of 14.3% by RECIST v1.1. Median PFS was 2.7 months, median OS was 16.4 months, and DCR was 54.8%, with responders achieving a median DoR of 15.2 months. Therapy was generally well tolerated and resulted in an increase of immune activation markers, with higher levels of activation in peripheral blood associated with response and improved survival. The combination of Imprime and pembrolizumab was safe and demonstrated immune activation in tumor tissues and peripheral blood in patients with TNBC. Improved response rates were observed compared to historical studies of ICI monotherapy in similar patient populations. Study number (ClinicalTrials.gov trial registration): NCT02981303.

Proximity-induced membrane protein degradation for cancer therapies

The selective modulation of membrane proteins presents a significant challenge in drug development, particularly in cancer therapies. However, conventional small molecules and biologics often face significant hurdles in effectively targeting membrane-bound proteins, largely due to the structural complexity of these proteins and their involvement in intricate cellular processes. In light of these limitations, proximity-induced protein modulation has recently emerged as a transformative approach. It leverages molecule-induced proximity strategies to commandeer endogenous cellular machinery for precise protein manipulation. One of these modulatory strategies is protein degradation, wherein membrane-targeting degraders derived from proximity-induction approaches offer a unique therapeutic avenue by inducing the irreversible removal of key oncogenic and immune-regulatory proteins to combat cancer. This review explores the fundamental principles underlying proximity-driven membrane protein degradation, highlighting key strategies such as LYTACs, PROTABs, TransTACs, and IFLD that are reshaping targeted cancer therapy. We discuss recent technological advancements in the application of proximity-induced degraders across breast cancer, lung cancer, immunotherapy, and other malignancies, underscoring how these innovative approaches have demonstrated significant therapeutic potential. Lastly, while these emerging technologies offer significant promise, they still face substantial limitations, including drug delivery, selectivity, and resistance mechanisms that need to be addressed to achieve successful clinical translation.

PILRα on tumor cells interacts with the T cell surface protein CD99 to suppress antitumor immunity

Immune checkpoint blockade using anti-programmed cell death protein 1/programmed cell death 1 ligand 1 antibody effectively targets the tumor-T cell interaction in cancer treatment, yet the overall response rate of less than 30% necessitates the identification of additional immune checkpoints modulating T cell function. Here, we identified the tumor cell-expressed paired immunoglobulin-like type 2 receptor alpha (PILRα) as an immune suppressor targeting T cells using high-throughput screening. PILRα inhibits T cell activation, proliferation and effector function by targeting CD99, a T cell surface antigen, suppressing ZAP70/NFAT/IL-2/JAK/STAT signaling. A cluster of O-glycosylated serine and threonine residues within the stalk region is critical for PILRα-CD99 interactions. Blocking these interactions with a stalk-targeting anti-PILRα antibody enhances T cell antitumor immunity and suppresses tumor growth. When combined with programmed cell death protein 1 antibody, anti-PILRα antibody shows synergistic tumor suppression. Notably, PILRα is highly expressed in several human cancers and predicts poor prognosis. These findings unveil PILRα as an immune checkpoint with therapeutic potential for clinical cancer immunotherapy.

Current Status of Immune Checkpoint Inhibitors and Treatment Responsive Biomarkers for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC), accounting for about 10%-20% of all breast cancer cases, is characterized by its aggressive nature, high recurrence rates, and poor prognosis. Unlike other breast cancer subtypes, TNBC lacks hormone receptors and specific molecular targets, limiting therapeutic options. In recent years, immune checkpoint inhibitors (ICIs) have shown promise in treating TNBC by targeting immune evasion mechanisms. Despite these advancements, several issues remain unresolved, including low response rates in programmed cell death ligand 1 (PD-L1) negative TNBC subtypes and the challenge of predicting which patients will benefit from ICIs. Consequently, there is growing interest in identifying reliable biomarkers beyond PD-L1 expression. This review synthesizes recent studies to provide a comprehensive perspective on ICI therapy in TNBC, clarifying the status of single-agent ICI therapies and combination strategies, emphasizing the need for further research into biomarkers. These insights provide clues for more personalized and effective treatment approaches, ultimately aiming to improve clinical outcomes for patients with TNBC.

Reprogramming the breast tumor immune microenvironment: cold-to-hot transition for enhanced immunotherapy

This review discusses reprogramming the breast tumor immune microenvironment from an immunosuppressive cold state to an immunologically active hot state. A complex interplay is revealed, in which the accumulation of metabolic byproducts-such as lactate, reactive oxygen species (ROS), and ammonia-is shown to impair T-cell function and promote tumor immune escape. It is demonstrated that the tumor microenvironment (TME) is dominated by immunosuppressive cytokines, including interleukin-10 (IL-10), transforming growth factorβ (TGFβ), and IL-35. Notably, IL-35 is produced by regulatory T cells and breast cancer cells. The conversion of conventional T cells into IL-35-producing induced regulatory T cells, along with the inhibition of pro-inflammatory cytokine secretion, contributes to the suppression of anti-tumor immunity. It is further demonstrated that key immune checkpoint molecules-such as PD-1, PDL1, CTLA-4, TIM-3, LAG-3, and TIGIT-are upregulated within the TME, leading to Tcell exhaustion and diminished immune responses. The blockade of these checkpoints is shown to restore T-cell functionality and is proposed as a strategy to convert cold tumors into hot ones with robust effector cell infiltration. The therapeutic potential of chimeric antigen receptor (CAR)T cell therapy is also explored, and targeting specific tumor-associated antigens, such as glycoproteins and receptor tyrosine kinases, is highlighted. It is suggested that CART cell efficacy can be enhanced by combining these cells with immune checkpoint inhibitors and other immunomodulatory agents, thereby overcoming the barriers imposed by the immunosuppressive TME. Moreover, the role of the microbiome in regulating estrogen metabolism and systemic inflammation is reviewed. Alterations in the gut microbiota are shown to affect the TME, and microbiome-based interventions are proposed as an additional means to facilitate the cold-to-hot transition. It is concluded that by targeting the metabolic and immunological pathways that underpin immune suppression-through combination strategies involving checkpoint blockade, CART cell therapies, and microbiome modulation-the conversion of the breast TME from cold to hot can be achieved. This reprogramming is anticipated to enhance immune cell infiltration and function, thereby improving the overall efficacy of immunotherapies and leading to better clinical outcomes for breast cancer patients.

The Interplay Between DNA Repair and the Immune Microenvironment in Pancreatic Cancer

This narrative review describes the relationship between DNA repair and the immune microenvironment in pancreatic cancer and its potential clinical relevance. Pancreatic cancer is a devastating disease, often diagnosed at an advanced and incurable stage. BRCA or PALB2 mutations occur in a small subset, disabling accurate DNA double-strand break repair and sensitizing tumors to platinum-based chemotherapy and poly-ADP ribose polymerase inhibitors. While immune checkpoint blockade targeting PD1 and CTLA4 is ineffective for most patients, accumulating translational work indicates that those with BRCA or PALB2 mutations harbor a distinct and more permissive immune microenvironment. The phase 2 TAPUR study and retrospective series demonstrate that combined PD1 and CTLA4 inhibition can be effective for this subgroup of patients. In this manuscript, we review the current treatment landscape, the underlying mechanisms for immune resistance, and the interplay between defective DNA repair and the immune microenvironment in pancreatic cancer.

Quantitative proteomics analysis of triple-negative breast cancers

Triple-negative breast cancer (TNBC) accounts for approximately 15% of all Breast Cancer (BC) cases with poorer prognosis and clinical outcomes compared to other BC subtypes due to greater tumor heterogeneity and few therapeutically targetable oncogenic drivers. To reveal actionable pathways for anti-cancer treatment, we use a proteomic approach to quantitatively compare the abundances of 6306 proteins across 55 formalin-fixed and paraffin-embedded (FFPE) TNBC tumors. We identified four major TNBC clusters by unsupervised clustering analysis of protein abundances. Analyses of clinicopathological characteristics revealed associations between the proteomic profiles and clinical phenotypes exhibited by each subtype. We validate the findings by inferring immune and stromal cell type composition from genome-wide DNA methylation profiles. Finally, quantitative proteomics on TNBC cell lines was conducted to identify in vitro models for each subtype. Collectively, our data provide subtype-specific insights into molecular drivers, clinicopathological phenotypes, tumor microenvironment (TME) compositions, and potential pharmacologic vulnerabilities for further investigations.

Role of Tumor-Associated Macrophages in Breast Cancer Immunotherapy

Breast cancer (BC) is the second leading cause of death among women worldwide. Immunotherapy has become an effective treatment for BC patients due to the rapid development of medical technology. Considerable breakthroughs have been made in research, marking the beginning of a new era in cancer treatment. Among them, various cancer immunotherapies such as immune checkpoint inhibitors (ICIs), cancer vaccines, and adoptive cell transfer are effective and have good prospects. The tumor microenvironment (TME) plays a crucial role in determining the outcomes of tumor immunotherapy. Tumor-associated macrophages (TAMs) are a key component of the TME, with an immunomodulatory effect closely related to the immune evasion of tumor cells, thereby affecting malignant progression. TAMs also significantly affect the therapeutic effect of ICIs (such as programmed death 1/programmed death ligand 1 (PD-1/PD-L1) inhibitors). TAMs are composed of multiple heterogeneous subpopulations, including M1 phenotypes macrophages (M1) and M2 phenotypes macrophages (M2). Furthermore, they mainly play an M2-like role and moderate a variety of harmful consequences such as angiogenesis, immunosuppression, and metastasis. Therefore, TAMs have become a key area of focus in the development of tumor therapies. However, several tumor immunotherapy studies demonstrated that ICIs are effective only in a small number of solid cancers, and tumor immunotherapy still faces relevant challenges in the treatment of solid tumors. This review explores the role of TAMs in BC immunotherapy, summarizing their involvement in BC development. It also explains the classification and functions of TAMs, outlines current tumor immunotherapy approaches and combination therapies, and discusses the challenges and potential strategies for TAMs in immuno-oncology treatments.

Atezolizumab and Trastuzumab Plus Chemotherapy for ERBB2-Positive Locally Advanced Resectable Gastric Cancer: A Randomized Clinical Trial

Importance

Effective treatment of locally advanced gastric cancer (GC) or gastroesophageal junction (GEJ) cancer remains a challenge.

Objective

To compare the efficacy and safety of atezolizumab plus trastuzumab plus capecitabine and oxaliplatin chemotherapy (XELOX) vs trastuzumab plus XELOX in Chinese patients with locally advanced human epidermal growth factor receptor 2 (ERBB2; formerly HER2)-positive GC or adenocarcinoma of the GEJ.

Design, Setting, and Participants

This was an open-label phase 2 randomized clinical trial conducted at 8 study sites in China. Patient recruitment started on February 25, 2021, and this study is ongoing as participants are still being actively followed up. Chinese patients eligible for surgery with locally advanced ERBB2-positive GC or adenocarcinoma of the GEJ were included. Data were analyzed from March 2021 to October 2023.

Interventions

Eligible patients were enrolled and randomly assigned 1:1 to perioperative treatment with either atezolizumab plus trastuzumab plus XELOX (arm A) or trastuzumab plus XELOX (arm B) for 3 neoadjuvant cycles (3 weeks per cycle) and 5 adjuvant cycles.

Main Outcomes and Measures

The primary efficacy end point was the pathological complete response (pCR) rate following completion of neoadjuvant therapy and surgery.

Results

In total, 42 patients were screened and randomly assigned to arm A (n = 21) or arm B (n = 21). The median (range) ages were 61 (33-72) years and 65 (49-72) years in arm A and arm B, respectively, and 39 patients (93%) were male. The pCR rate was significantly higher in arm A (8 [38%]) than arm B (3 [14%]; difference, 23.8%; 90% CI, 1.3-44.7). Age younger than 65 years, male sex, and intestinal Lauren classification were significantly associated with a better pCR rate in arm A. Median event-free survival, disease-free survival, and overall survival were not reached. Based on the same way of interpretation, major pathologic response should be statistically significantly different between the 2 arms, while other outcome measures remained not significantly different. The incidence of treatment-emergent adverse events was 100% (21 of 21) and 100% (21 of 21) in arms A and B, respectively; grade 3 or higher TEAEs, 57% (12 of 21) and 67% (14 of 21), respectively; and serious TEAEs, 29% (6 of 21) and 10% (2 of 21), respectively.

Conclusions and Relevance

In this randomized clinical trial, add-on atezolizumab to trastuzumab plus XELOX therapy demonstrated promising efficacy in this patient population, and no new safety concerns were raised.

Trial Registration

ClinicalTrials.gov Identifier: NCT04661150.

Exploration of Traditional Chinese Medicine Comprehensive Treatment of Triple Negative Breast Cancer Based on Molecular Pathological Mechanism

Triple-negative breast cancer (TNBC) is recognized as the most aggressive subtype of breast cancer and is associated with poor prognosis. Clinically, TNBC is associated with significant invasiveness, high propensity for metastasis, frequent recurrence, and unfavorable outcomes. The absence of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2 (HER2) in TNBC renders it unresponsive to endocrine therapies and treatments that target HER2. Consequently, the current therapeutic options are primarily confined to surgical intervention, adjuvant chemotherapy, and radiotherapy. Given the considerable heterogeneity of TNBC, targeted therapies have emerged as promising avenues for treatment. Furthermore, immunotherapy has demonstrated the potential to enhance overall survival and therapeutic response in patients with TNBC. Additionally, research indicates that traditional Chinese medicine (TCM) may yield beneficial effects in the management of this cancer subtype. This review aims to consolidate recent advancements in treatment strategies for TNBC, particularly those based on molecular subtypes.

Efficacy and Safety of Immunochemotherapy in Advanced Triple-negative Breast Cancer: A Meta-analysis of Randomised Clinical Trials

AIMS

Based on the existing controversial clinical research results, this study conducted a comprehensive meta-analysis of relevant literature to clarify the benefits of immunochemotherapy (ICT)-which combines immune checkpoint inhibitors and chemotherapy (CT)-for patients with advanced triple-negative breast cancer (aTNBC).

MATERILAS AND METHODS

A thorough literature search was conducted up to February 15, 2024. Subsequently, meta-analyses were performed to aggregate hazard ratios (HRs) for progression-free survival (PFS) and overall survival (OS), odds ratios (ORs) for objective response rate (ORR) and relative risks (RRs) for adverse events (AEs).

RESULTS

Six randomised clinical trials (RCTs) involving 3,105 patients met the inclusion criteria. In comparison with CT, ICT yielded significant enhancements in PFS (HR, 0.80; 95%CI: 0.73-0.87), OS (HR, 0.87; 95%CI: 0.80-0.96), and ORR (OR, 1.34; 95%CI: 1.15-1.55) in the intention-to-treat population. However, ICT also exhibited an increase in grade ≥3 AEs (RR, 1.11; 95%CI: 1.04-1.19) and severe AEs (RR, 1.40; 95%CI: 1.18-1.66). Subgroup analyses revealed that ICT significantly improved PFS (HR, 0.67; 95%CI: 0.58-0.77), OS (HR, 0.75; 95%CI: 0.64-0.87), and ORR (OR, 1.47; 95%CI: 1.16-1.84) within the PD-L1-positive subgroup, whereas no statistically significant differences were detected for PD-L1-negative population.

CONCLUSION

ICT demonstrates superior efficacy over conventional CT in the treatment of aTNBC, albeit accompanied by heightened toxicity. Notably, the assessment of PD-L1 status may serve as a valuable biomarker in discerning aTNBC patients who are particularly predisposed to derive benefit from ICT.

PROSPERO NUMBER

CRD42024513270.

Breast cancer scoring based on a multiplexed profiling of soluble and cell-associated (immune) markers facilitates the prediction of pembrolizumab therapy

BACKGROUND

The immune checkpoint targeting is nowadays an integral part of cancer therapies. However, only a minority of patients experience long-term benefits. Thus, the identification of predictive biomarkers contributing to therapy response is urgently needed.

METHODS

Here, we analyzed different immune and tumor specific expression and secretion profiles in the peripheral blood and tumor samples of 50 breast cancer patients by multicolor flow cytometry and bead-based immunoassays at the time of diagnosis. Due to individual phenotype variations, we quantitatively scored 25 expressed and secreted immune-associated (e.g., LAG-3, PD-1, TIM-3, CD27) and tumor relevant markers (e.g., PD-L1, CD44, MHC-I, MHC-II) in immune checkpoint-treated triple negative breast cancer patients based on the current literature. The calculated score divided the patients into individuals with predicted pCR (total score of > 0) or predicted residual disease (total score of ≤ 0). At the end of the neoadjuvant therapy, the truly achieved pathological complete response (pCR; end of observation) was determined.

RESULTS

The calculated score was 79% in accordance with the achieved pCR at the time of surgery. Moreover, the sensitivity was 83.3%, the specificity 76.9%, the positive predictive value 62.5%, and the negative predictive value 90.9%. In addition, we identified a correlation of PD-1 and LAG-3 expression between tumor-associated and peripheral immune cells, which was independent of the subtype. Overall, PD-1 was the most frequently expressed checkpoint. However, in a number of patient-derived tumors, additional checkpoints as LAG-3 and TIM-3 were substantially (co-)expressed, which potentially compromises anti-PD-(L)1 mono-therapy.

CONCLUSIONS

This study represents a proof-of-principle to identify potential checkpoint therapy responders in advance at the time of diagnosis. The work was based on a scoring derived from a multiplexed marker profiling. However, larger patient cohorts need to be prospectively evaluated for further validation.

Genetically engineered macrophages reverse the immunosuppressive tumor microenvironment and improve immunotherapeutic efficacy in TNBC

The main challenges in current immunotherapy for triple-negative breast cancer (TNBC) lie in the immunosuppressive tumor microenvironment (TME). Considering tumor-associated macrophages (TAMs) are the most abundant immune cells in the TME, resetting TAMs is a promising strategy for ameliorating the immunosuppressive TME. Here, we developed genetically engineered macrophages (GEMs) with gene-carrying adenoviruses, to maintain the M1-like phenotype and directly deliver the immune regulators interleukin-12 and CXCL9 into local tumors, thereby reversing the immunosuppressive TME. In tumor-bearing mice, GEMs demonstrated targeted enrichment in tumors and successfully reprogramed TAMs to M1-like macrophages. Moreover, GEMs significantly enhanced the accumulation, proliferation, and activation of CD8+ T cells, mature dendritic cells, and natural killer cells within tumors, while diminishing M2-like macrophages, immunosuppressive myeloid-derived suppressor cells, and regulatory T cells. This treatment efficiently suppressed tumor growth. In addition, combination therapy with GEMs and anti-programmed cell death protein 1 further improved interferon-γ+CD8+ T cell percentages and tumor inhibition efficacy in an orthotopic murine TNBC model. Therefore, this study provides a novel strategy for reversing the immunosuppressive TME and improving immunotherapeutic efficacy through live macrophage-mediated gene delivery.

New progress in imaging diagnosis and immunotherapy of breast cancer

Breast cancer (BC) is a predominant malignancy among women globally, with its etiology remaining largely elusive. Diagnosis primarily relies on invasive histopathological methods, which are often limited by sample representation and processing time. Consequently, non-invasive imaging techniques such as mammography, ultrasound, and Magnetic Resonance Imaging (MRI) are indispensable for BC screening, diagnosis, staging, and treatment monitoring. Recent advancements in imaging technologies and artificial intelligence-driven radiomics have enhanced precision medicine by enabling early detection, accurate molecular subtyping, and personalized therapeutic strategies. Despite reductions in mortality through traditional treatments, challenges like tumor heterogeneity and therapeutic resistance persist. Immunotherapies, particularly PD-1/PD-L1 inhibitors, have emerged as promising alternatives. This review explores recent developments in BC imaging diagnostics and immunotherapeutic approaches, aiming to inform clinical practices and optimize therapeutic outcomes.

Biological and clinical significance of tumour-infiltrating lymphocytes in the era of immunotherapy: a multidimensional approach

Immune-checkpoint inhibitors (ICIs) have improved clinical outcomes across several solid tumour types. Prominent efforts have focused on understanding the anticancer mechanisms of these agents, identifying biomarkers of response and uncovering resistance mechanisms to develop new immunotherapeutic approaches. This research has underscored the crucial roles of the tumour microenvironment and, particularly, tumour-infiltrating lymphocytes (TILs) in immune-mediated tumour elimination. Numerous studies have evaluated the prognostic and predictive value of TILs and the mechanisms that govern T cell dysfunction, fuelled by technical developments in single-cell transcriptomics, proteomics, high-dimensional spatial platforms and advanced computational models. However, questions remain regarding the definition of TILs, optimal strategies to study them, specific roles of different TIL subpopulations and their clinical implications in different treatment contexts. Additionally, most studies have focused on the abundance of major TIL subpopulations but have not developed standardized quantification strategies or analysed other crucial aspects such as their functional profile, spatial distribution and/or arrangement, tumour antigen-reactivity, clonal diversity and heterogeneity. In this Review, we discuss a conceptual framework for the systematic study of TILs and summarize the evidence regarding their biological properties and biomarker potential for ICI therapy. We also highlight opportunities, challenges and strategies to support future developments in this field.

Sciatic nerve stimulation enhances NK cell cytotoxicity through dopamine signaling and synergizes immunotherapy in triple-negative breast cancer

AIMS

Triple-negative breast cancer (TNBC) has shown resistance to immunotherapy. Stimulating ProkR2-bearing sensory neurons of the sciatic nerve has been reported to regulate immune function by catecholamine release through the vagal-adrenal axis. We aimed to investigate the impact of sciatic nerve stimulation on anti-tumor immune responses and immunotherapy efficacy in TNBC.

METHODS

We implemented ProkR2-bearing neuron stimulation in a TNBC mouse model. Single-cell RNA sequencing, flow cytometry, and immunohistochemistry were employed to uncover alterations in the tumor immune microenvironment. Immune cell depletion and receptor inhibitors were used to verify the cellular and molecular mechanisms by which neurostimulation regulates anti-tumor immunity.

RESULTS

Sciatic nerve stimulation inhibited 4T1 tumor growth by activating natural killer (NK) cells in the tumor microenvironment. The D1-like dopamine receptor-cAMP-PKA-CREB signaling pathway is essential for enhanced NK cell cytotoxicity and tumor inhibition induced by neurostimulation. Neurostimulation upregulated tumor PD-L1 expression through IFN-gamma pathway. Combining sciatic nerve stimulation with anti-PD-1 therapy resulted in superior tumor control compared to either approach alone and demonstrated good safety.

CONCLUSIONS

This research addresses a long-standing gap in understanding neuro-immune regulation in cancer treatment, presenting a promising strategy for overcoming immunoresistance in TNBC.

Gamabufotalin loaded micro-nanocomposites for multimodal therapy of metastatic TNBC by efficiently inducing ICD

Gamabufotalin (CS-6), a main active compound derived from Chinese medicine Chansu, exhibits a robust inhibitory effect on programmed death-ligand 1 (PD-L1) in triple-negative breast cancer (TNBC) cells. Despite its potential for tumor therapy, the medical application of CS-6 is constrained by its hydrophobic nature, lack of targeting capability, and weak immunogenic cell death (ICD) effect. To address these limitations and improve the therapeutic efficiency of this drug against metastatic TNBC, we designed a new kind of CS-6@CPB-S.lux that integrates carboxy-Prussian blue nanoparticles (CPB NPs), CS-6, and attenuated Salmonella typhimurium (S.lux) for TNBC therapy. In vitro and in vivo results have confirmed that CS-6@CPB NPs were efficiently delivered to neoplastic tissue by the tumor hypoxic chemotaxis property of S.lux, wherein the nanomedicine induced significant tumor cell necroptosis and apoptosis via photothermal therapy (PTT) of CPB NPs and chemotherapy of CS-6, which elicited ICD and inhibited PD-L1 expression, resulting in dendritic cells (DCs) maturation and effector T cells activation to comprehensively eliminate tumors. Additionally, the CS-6@CPB-S.lux + Laser treatment significantly transformed the immunosuppressive tumor microenvironment (TME), enhancing antitumor immunity through promoting the polarization of tumor-associated macrophages into antitumorigenic M1 and reducing Tregs recruitment. Consequently, this comprehensive therapy not only inhibited primary and abscopal tumor progression but also prevented TNBC metastasis, which significantly prolonged survival time in animal models. In summary, these findings indicated an alternative approach for metastatic TNBC therapy.

Androgen receptor expression distribution characteristics in young female breast cancer patients in China: a study of clinicopathological features

Background

The expression of androgen receptor (AR) in breast cancer has potential implications for predicting clinical outcomes, especially amongst young female patients. Numerous studies have reported that the co-expression of AR with hormone receptors (HRs) is correlated with a favorable prognosis in breast cancer. However, research on the frequency and distribution of AR expression in Chinese breast cancer patients is limited. This study aims to investigate the relationship between AR expression and the expression of progesterone receptor (PR), estrogen receptor (ER), P53, human epidermal growth factor receptor 2 (HER2), and epidermal growth factor receptor (EGFR) in breast cancer patients, and the distribution of molecular subtypes of breast cancer. Further, we aim to explore the pattern of AR expression and its correlation with clinicopathological features and prognosis among young female patients in China.

Methods

Formalin-fixed paraffin-embedded tissue samples from 321 young female breast cancer patients were collected from the Third Hospital of Nanchang. Immunohistochemistry was used to assess the expression of AR, ER, PR, HER2, and Ki67. A statistical analysis was conducted to explore the correlation between the expression of AR and these molecular markers, as well as their distribution across different molecular subtypes of breast cancer, and their prognostic significance.

Results

A total of 321 breast cancer patients were included in this study. Significant correlations were found between the positive expression of AR and the high expression of PR and ER (P<0.001). The rate of P53 positivity was significantly higher in the AR-positive patients than the AR-negative patients (P=0.01). Additionally, HER2 expression was significantly higher in the AR-positive patients than the AR-negative patients (P<0.001). Notably, the rate of EGFR positivity was significantly lower in the AR-positive patients compared to AR-negative patients (P<0.001). In relation to the molecular subtypes, AR positivity was significantly associated with the luminal A subtype (P<0.001), while the triple-negative breast cancer (TNBC)/basal-like subtype was more common in the AR-negative patients.

Conclusions

This study revealed that in young female breast cancer patients in China, AR-positive breast cancer was significantly associated with the high expression of HRs, increased P53 expression and reduced EGFR expression. The expression status of AR can serve as a biomarker to predict therapeutic responses but could also influence the classification of molecular subtypes and the selection of treatment strategies.

PD-1/PD-L1 inhibitors plus chemotherapy versus chemotherapy alone for Asian patients with advanced triple-negative breast cancer: a phase III RCTs based meta-analysis

Background

Advanced triple-negative breast cancer (TNBC) presents significant therapeutic challenges, particularly in Asian populations, which exhibit distinct biological and genetic characteristics. Immunotherapy combined with chemotherapy has emerged as a promising approach; however, its efficacy compared to chemotherapy alone remains under investigation. This meta-analysis aims to evaluate the clinical outcomes of PD-1/PD-L1 inhibitors combined with chemotherapy (PIC) versus chemotherapy alone in the treatment of advanced TNBC in Asian patients.

Methods

A systematic literature search was performed across six databases for phase 3 randomized controlled trials (RCTs). Only studies comparing the outcomes of PIC versus chemotherapy alone in patients with advanced TNBC, including subgroup analyses of Asian populations, were included. Data were pooled to assess overall survival (OS), progression-free survival (PFS), responses, and safety profiles.

Results

A total of 1041 patients from five phase 3 RCTs were included in the final analysis. Compared to chemotherapy alone, PIC therapy significantly improved PFS (hazard ratio [HR]: 0.74 [0.62, 0.88], P = 0.0008). No significant difference was observed in OS (HR: 0.78 [0.55, 1.12], P = 0.18), although a slight trend favoring PIC therapy was noted. Among PD-L1-positive patients, both OS (HR: 0.62 [0.44, 0.86], P = 0.005) and PFS (HR: 0.66 [0.50, 0.86], P = 0.003) were significantly improved in the PIC group. The PIC group also exhibited a substantially higher OS rate at 12-36 months and a higher PFS rate at 6-30 months. However, the incidence of immune-related AEs (irAEs) (risk ratio [RR]: 1.69 [1.33, 2.15], P < 0.0001) and grade 3-5 irAEs (RR: 3.11 [1.59, 6.10], P = 0.001) was significantly higher in the PIC group. The most common irAEs in the PIC group were hypothyroidism (14.40%), dermatitis (10.00%), and infusion reactions (8.85%). Both treatment groups exhibited similar response rates and treatment-related AEs (TRAEs).

Conclusions

In Asian patients with advanced TNBC, PIC significantly improved survival compared to chemotherapy alone. Although the combination therapy was associated with a higher incidence of irAEs, its clinical benefits support its use as a viable treatment option for this population.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42024622428.

Divide and Conquer-Targeted Therapy for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive and malignant type of breast cancer with limited treatment options and poor prognosis. One of the most significant impediments in TNBC treatment is the high heterogeneity of this disease, as highlighted by the detection of several molecular subtypes of TNBC. Each subtype is driven by distinct mutations and pathway aberrations, giving rise to specific molecular characteristics closely connected to clinical behavior, outcomes, and drug sensitivity. This review summarizes the knowledge regarding TNBC molecular subtypes and how it can be harnessed to devise tailored treatment strategies instead of blindly using targeted drugs. We provide an overview of novel targeted agents and key insights about new treatment modalities with an emphasis on the androgen receptor signaling pathway, cancer stem cell-associated pathways, phosphatidylinositol 3-kinase (PI3K)/AKT pathway, growth factor signaling, and immunotherapy.

Temporal and spatial composition of the tumor microenvironment predicts response to immune checkpoint inhibition

Immune checkpoint inhibition (ICI) has fundamentally changed cancer treatment. However, only a minority of patients with metastatic triple negative breast cancer (TNBC) benefit from ICI, and the determinants of response remain largely unknown. To better understand the factors influencing patient outcome, we assembled a longitudinal cohort with tissue from multiple timepoints, including primary tumor, pre-treatment metastatic tumor, and on-treatment metastatic tumor from 117 patients treated with ICI (nivolumab) in the phase II TONIC trial. We used highly multiplexed imaging to quantify the subcellular localization of 37 proteins in each tumor. To extract meaningful information from the imaging data, we developed SpaceCat, a computational pipeline that quantifies features from imaging data such as cell density, cell diversity, spatial structure, and functional marker expression. We applied SpaceCat to 678 images from 294 tumors, generating more than 800 distinct features per tumor. Spatial features were more predictive of patient outcome, including features like the degree of mixing between cancer and immune cells, the diversity of the neighboring immune cells surrounding cancer cells, and the degree of T cell infiltration at the tumor border. Non-spatial features, including the ratio between T cell subsets and cancer cells and PD-L1 levels on myeloid cells, were also associated with patient outcome. Surprisingly, we did not identify robust predictors of response in the primary tumors. In contrast, the metastatic tumors had numerous features which predicted response. Some of these features, such as the cellular diversity at the tumor border, were shared across timepoints, but many of the features, such as T cell infiltration at the tumor border, were predictive of response at only a single timepoint. We trained multivariate models on all of the features in the dataset, finding that we could accurately predict patient outcome from the pre-treatment metastatic tumors, with improved performance using the on-treatment tumors. We validated our findings in matched bulk RNA-seq data, finding the most informative features from the on-treatment samples. Our study highlights the importance of profiling sequential tumor biopsies to understand the evolution of the tumor microenvironment, elucidating the temporal and spatial dynamics underlying patient responses and underscoring the need for further research on the prognostic role of metastatic tissue and its utility in stratifying patients for ICI.

Hormone therapy enhances anti-PD1 efficacy in premenopausal estrogen receptor-positive and HER2-negative advanced breast cancer

The efficacy of immunotherapy for estrogen receptor-positive/HER2-negative (ER+/HER2-) metastatic breast cancer (MBC) has not been proven. We conduct a phase 1b/2 trial to assess the efficacy of combining pembrolizumab (anti-PD1 antibody), exemestane (nonsteroidal aromatase inhibitor), and leuprolide (gonadotropin-releasing hormone agonist) for 15 patients with premenopausal ER+/HER2- MBC who had failed one to two lines of hormone therapy (HT) without chemotherapy. The primary endpoint of progression-free survival rate at 8 months (i.e., 64.3%) is achieved. Moreover, 5 of the 14 evaluable subjects exhibited partial responses (overall response rate = 35.7%). The combination of anti-PD1 antibody and anti-hormone therapy is associated with an enhanced immunoreactive microenvironment influencing treatment efficacy, as observed in pre- and post-treatment tumor samples through NanoString analysis. Post-treatment tumors are associated with increased immune response and immune cells. The findings indicate that combining HT with anti-PD1 antibody is a promising treatment strategy for patients with premenopausal ER+/HER2- MBC. This study was registered at ClinicalTrials.gov (NCT02990845).

Long-Term and Sustained Remission of Advanced Triple-Negative Breast Cancer with Large Chest Wall Lesions after Transient Chemoimmunotherapy: A Case Report

Introduction

We report a case of advanced triple-negative breast cancer (TNBC) with special clinical manifestations, in which a durable remission was achieved after short-term administration of toripalimab combined with chemotherapy. The progress, advantages, and unique experience of chemoimmunotherapy in TNBC were examined.

Case Presentation

A patient with TNBC with local recurrence 2 years following surgery, with inoperable large chest wall lesions and positive PD-L1 as the main manifestations, was treated with toripalimab plus paclitaxel (albumin-bound) for 5 months and achieved a partial remission. Twenty-five months after the discontinuation of treatment, the chest wall lesions exhibited a slow but continuous decline, until they achieved a nearly complete remission; however, the patient eventually died from cancer progression.

Conclusion

Typically, chest wall recurrence in TNBC has a poor prognosis; however, recurrence was rapidly controlled, sustained remission was achieved after immunotherapy combined with chemotherapy, and the curative effect continued after drug withdrawal, which is a rare occurrence. Thus, the tailing effect of immune checkpoint inhibitors was confirmed in the treatment of TNBC.

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.

Current and future immunotherapy for breast cancer

Substantial therapeutic advancement has been made in the field of immunotherapy in breast cancer. The immune checkpoint inhibitor pembrolizumab in combination with chemotherapy received FDA approval for both PD-L1 positive metastatic and early-stage triple-negative breast cancer, while ongoing clinical trials seek to expand the current treatment landscape for immune checkpoint inhibitors in hormone receptor positive and HER2 positive breast cancer. Antibody drug conjugates are FDA approved for triple negative and HER2+ disease, and are being studied in combination with immune checkpoint inhibitors. Vaccines and bispecific antibodies are areas of active research. Studies of cellular therapies such as tumor infiltrating lymphocytes, chimeric antigen receptor-T cells and T cell receptor engineered cells are promising and ongoing. This review provides an update of recent major clinical trials of immunotherapy in breast cancer and discusses future directions in the treatment of breast cancer.

Identifying subgroups deriving the most benefit from PD-1 checkpoint inhibition plus chemotherapy in advanced metastatic triple-negative breast cancer: a systematic review and meta-analysis

BACKGROUND

The combination of immunotherapy and chemotherapy has demonstrated an enhancement in progression-free survival (PFS) for individuals with advanced and metastatic triple-negative breast cancer (TNBC) when compared to the use of chemotherapy alone. Nevertheless, the extent to which different subgroups of metastatic TNBC patients experience this benefit remains uncertain.

OBJECTIVES

Our objective was to conduct subgroup analyses to more precisely identify the factors influencing these outcomes.

MATERIALS AND METHODS

The PubMed database was searched until Dec 2023 for studies that compared PD-1 checkpoint inhibitors plus chemotherapy (ICT) with chemotherapy (CT) alone. The primary outcome of interest was progression-free survival (PFS). Review Manager (RevMan) version 5.4. was used for the data analysis.

RESULTS

Four randomized controlled trials (RCTs) comprising 2468 advanced and metastatic TNBC were included in this systematic review and meta-analysis. PFS surge with combined therapy was observed in White (HR 0.80 [0.70, 0.91], p = 0.0007) and Asian ethnicities (HR 0.73 [0.58, 0.93], p = 0.01) but not in Blacks (HR 0.72 [0.42, 1.24], p = 0.24). Overall, patients with distant metastasis demonstrated to derive the PFS benefit from additional immunotherapy (HR 0.87 [0.77, 0.99], p = 0.03); however, metastasis to individual distant site was associated with failure to achieve any treatment difference (Bone: HR 0.79 [0.41, 1.52], p = 0.49; Lung: HR 0.85 [0.70, 1.04], p = 0.11; Liver: HR 0.80 [0.64, 1.01], p = 0.06). While number of metastases > 3 also showed to impact the PFS advantage (HR 0.89 [0.69, 1.16], p = 0.39). While patients, regardless of prior chemotherapy, experienced a notable enhancement in PFS with ICT (Overall: HR 0.79 [0.71, 0.88], p < 0.0001; Yes: HR 0.87 [0.76, 1.00], p = 0.05; No: HR 0.67 [0.56, 0.80], p < 0.00001), those previously exposed to chemotherapy exhibited a significantly smaller PFS advantage compared to those without prior chemotherapy, as evidenced by a significant subgroup difference (Test for subgroup difference: P = 0.02, I2 = 82.2%). Patients lacking PD-L1 expression also failed to achieve any additional benefit from immunotherapy (PD-L1-: HR 0.95 [0.81, 1.12]; p = 0.54; PD-L1+: HR 0.73 [0.64, 0.85], p < 0.0001). Age, ECOG status, and presentation with de novo metastasis/recurrent shown no impact on IT-associated PFS advantage.

CONCLUSIONS

Patient- and treatment- related factors such as ethnicity, distant metastases, number of metastases (> 3), previous exposure to chemotherapy and PD-L1 expression, seem to influence or restrict the advantage in progression-free survival associated with the addition of immunotherapy to chemotherapy, as opposed to chemotherapy alone, in patients with advanced and metastatic TNBC. Larger studies are warranted to validate these outcomes.

NF-κB associated markers of prognosis in early and metastatic triple negative breast cancer

BACKGROUND

Triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer. While PD-1 based immunotherapies overall have led to improved treatment outcomes for this disease, a diverse response to frontline chemotherapy and immunotherapy still exist in TNBC, highlighting the need for more robust prognostic markers.

METHODS

Tumor-intrinsic immunotranscriptomics, serum cytokine profiling, and tumor burden studies were conducted in two syngeneic mouse models to assess differential effects in both the early-stage and metastatic setting. Bioinformatic analyses of both early and metastatic TNBC patient data were performed to assess if identified NF-κB-associated factors are associated with improved patient clinical outcomes.

RESULTS

NF-κB signaling driven by lymphotoxin beta expression is associated with tumor regression in TNBC mouse models. Furthermore, lymphotoxin beta expression in patient TNBC cohorts is prognostic of improved survival outcomes.

CONCLUSIONS

This study highlights the potential role for NF-κB-associated factors, specifically lymphotoxin beta to be used as prognostic markers in TNBC, which could ultimately provide insight for improved targeted treatment approaches in the clinic.

Global biomarker trends in triple-negative breast cancer research: a bibliometric analysis

BACKGROUND

Triple-negative breast cancer (TNBC) is defined as breast cancer that is negative for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER-2) in cancer tissue. The lack of specific biomarkers makes the diagnosis and prognosis of TNBC challenging.

METHOD

A comprehensive literature review and bibliometric analysis was performed using CiteSpace, VOSviewer and Scimago Graphica.

RESULTS

TNBC biomarker research has been growing rapidly in recent years, reflecting the enormous academic interest in TNBC biomarker research. A total of 127 journals published relevant studies and 1749 authors were involved in the field, with developed countries such as the United States, France, and the United Kingdom contributing greatly to the field. Collaborative network analysis found that the research in this field has not yet formed good communication and interaction, and the partnership should be strengthened in the future in order to promote the in-depth development of TNBC biomarker research. A comprehensive analysis of keywords and co-cited literature, etc. found that TNBC biomarker research mainly focuses on immune checkpoint markers, microenvironment-related markers, circulating tumor DNA, metabolic markers, genomics markers and so on. These research hotspots will help to better understand the molecular characteristics and biological processes of TNBC, and provide more accurate biomarkers for its diagnosis, treatment and prognosis.

CONCLUSIONS

The bibliometric analysis highlighted global trends and key directions in TNBC biomarker research. Future developments in TNBC biomarker research are likely to be in the direction of multi-omics integration, meticulous study of the microenvironment, targeted therapeutic biomarkers, application of liquid biopsy, application of machine learning and artificial intelligence, and individualized therapeutic strategies. Young scholars should learn and collaborate across disciplines, pay attention to new technologies and methods, improve their data analysis skills, and continue to follow up on the latest research trends in order to meet the challenges and opportunities in the field of TNBC biomarkers.

Prognostic value of tumor-infiltrating lymphocyte subtypes and microorganisms in triple-negative breast cancer

ABSTRACT

Tumor-infiltrating lymphocytes (TILs) are key components of the tumor microenvironment (TME) and serve as prognostic markers for breast cancer. Patients with high TIL infiltration generally experience better clinical outcomes and extended survival compared to those with low TIL infiltration. However, as the TME is highly complex and TIL subtypes perform distinct biological functions, TILs may only provide an approximate indication of tumor immune status, potentially leading to biased prognostic results. Therefore, we reviewed the interactions between immune-infiltrating subtypes and tumor cells throughout the entire TME. By examining the antitumor or protumor effects of each TIL subtype, we aimed to better characterize the tumor immune landscape, offering more accurate and comprehensive insights for guiding triple-negative breast cancer (TNBC) treatment. In addition, this approach could lead to the development of new therapeutic targets, enabling tailored treatment strategies and precision medicine. Accumulating evidence suggests that the intestinal microbiome and its metabolites influence antitumor responses by modulating innate and adaptive immunity, with specific bacteria potentially serving as biomarkers for predicting clinical responses. Various studies have identified microorganisms in breast tissue, previously considered sterile, revealing differences in breast microbial composition between patients with breast cancer and controls, as well as associations between specific breast microorganisms and clinicopathologic features, including immune correlations. The aim of this review was to provide a more comprehensive set of prognostic markers for TNBC and to tap into potential-specific therapeutic targets.

Biomarkers in breast cancer 2024: an updated consensus statement by the Spanish Society of Medical Oncology and the Spanish Society of Pathology

This revised consensus statement of the Spanish Society of Medical Oncology (SEOM) and the Spanish Society of Pathological Anatomy (SEAP) updates the recommendations for biomarkers use in the diagnosis and treatment of breast cancer that we first published in 2018. The expert group recommends determining in early breast cancer the estrogen receptor (ER), progesterone receptor (PR), Ki-67, and Human Epidermal growth factor Receptor 2 (HER2), as well as BReast CAncer (BRCA) genes in high-risk HER2-negative breast cancer, to assist prognosis and help in indicating the therapeutic options, including hormone therapy, chemotherapy, anti-HER2 therapy, and other targeted therapies. One of the four available genetic prognostic platforms (Oncotype DX®, MammaPrint®, Prosigna®, or EndoPredict®) may be used in ER-positive patients with early breast cancer to establish a prognostic category and help decide with the patient whether adjuvant treatment may be limited to hormonal therapy. In second-line advanced breast cancer, in addition, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) and estrogen receptor 1 (ESR1) should be tested in hormone-sensitive cases, BRCA gene mutations in HER2-negative cancers, and in triple-negative breast cancer (TNBC), programmed cell death-1 ligand (PD-L1). Newer biomarkers and technologies, including tumor-infiltrating lymphocytes (TILs), homologous recombination deficiency (HRD) testing, serine/threonine kinase (AKT) pathway activation, and next-generation sequencing (NGS), are at this point investigational.

Global biomarker trends in triple-negative breast cancer research: a bibliometric analysis

BACKGROUND

Triple-negative breast cancer (TNBC) is defined as breast cancer that is negative for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER-2) in cancer tissue. The lack of specific biomarkers makes the diagnosis and prognosis of TNBC challenging.

METHOD

A comprehensive literature review and bibliometric analysis was performed using CiteSpace, VOSviewer and Scimago Graphica.

RESULTS

TNBC biomarker research has been growing rapidly in recent years, reflecting the enormous academic interest in TNBC biomarker research. A total of 127 journals published relevant studies and 1749 authors were involved in the field, with developed countries such as the United States, France, and the United Kingdom contributing greatly to the field. Collaborative network analysis found that the research in this field has not yet formed good communication and interaction, and the partnership should be strengthened in the future in order to promote the in-depth development of TNBC biomarker research. A comprehensive analysis of keywords and co-cited literature, etc. found that TNBC biomarker research mainly focuses on immune checkpoint markers, microenvironment-related markers, circulating tumor DNA, metabolic markers, genomics markers and so on. These research hotspots will help to better understand the molecular characteristics and biological processes of TNBC, and provide more accurate biomarkers for its diagnosis, treatment and prognosis.

CONCLUSIONS

The bibliometric analysis highlighted global trends and key directions in TNBC biomarker research. Future developments in TNBC biomarker research are likely to be in the direction of multi-omics integration, meticulous study of the microenvironment, targeted therapeutic biomarkers, application of liquid biopsy, application of machine learning and artificial intelligence, and individualized therapeutic strategies. Young scholars should learn and collaborate across disciplines, pay attention to new technologies and methods, improve their data analysis skills, and continue to follow up on the latest research trends in order to meet the challenges and opportunities in the field of TNBC biomarkers.

Efficacy and safety of PARPis combined with an ICIs for advanced or metastatic triple-negative breast cancer: a single-arm meta-analysis

Although the intervention for triple-negative breast cancer (TNBC) patients has improved and survival time has increased, the combination of immune checkpoint inhibitors(ICIs) and PARP inhibitors (Poly ADP-Ribose Polymerase inhibitors, PARPis) is still controversial. Previous studies revealed that the combined use of ICIs and PARPis led to increased antitumor activity. However, most of these combined regimens are nonrandomized controlled trials with small sample sizes. The purpose of this meta-analysis was to evaluate the efficacy and safety of ICIs combined with PARPis in patients with advanced or metastatic TNBC. The PubMed, Embase, Cochrane Library and Web of Science databases were systematically searched. The results including the objective remission rate (ORR), disease control rate (DCR), progression-free survival (PFS) and adverse events (AEs), were subjected to further analysis. Four studies involving 110 subjects were included in this meta-analysis. The combined ORR and DCR were 23.6% and 53.6%, respectively; while the ORR and DCR of BRCAmut patients were 38.1% and 71.4%, respectively. The median PFS of the patients was 4.29 months. As for safety, the most common AEs were nausea (49.0%), anemia (44.3%) and fatigue (40.6%). Most of them were grade 1 or 2, and the incidence of adverse events ≥ III was obviously low. Except for anemia, the incidence of AEs ≥ III was < 10%. This meta-analysis revealed that the combination of ICIs and PARPis has good efficacy and safety for advanced or metastatic TNBC patients.

PD-1/PD-L1 immune checkpoint blockade in breast cancer: research insights and sensitization strategies

Immunotherapy targeting programmed cell death-1 (PD-1) and PD-L1 immune checkpoints has reshaped treatment paradigms across several cancers, including breast cancer. Combining PD-1/PD-L1 immune checkpoint blockade (ICB) with chemotherapy has shown promising efficacy in both early and metastatic triple-negative breast cancer, although only a subset of patients experiences durable responses. Identifying responders and optimizing immune drug selection are therefore critical. The effectiveness of PD-1/PD-L1 immunotherapy depends on both tumor-intrinsic factors and the extrinsic cell-cell interactions within the tumor microenvironment (TME). This review systematically summarizes the key findings from clinical trials of ICBs in breast cancer and examines the mechanisms underlying PD-L1 expression regulation. We also highlight recent advances in identifying potential biomarkers for PD-1/PD-L1 therapy and emerging evidence of TME alterations following treatment. Among these, the quantity, immunophenotype, and spatial distribution of tumor-infiltrating lymphocytes stand out as promising biomarkers. Additionally, we explore strategies to enhance the effectiveness of ICBs in breast cancer, aiming to support the development of personalized treatment approaches tailored to the unique characteristics of each patient's tumor.

High CTLA-4 gene expression is an independent good prognosis factor in breast cancer patients, especially in the HER2-enriched subtype

BACKGROUND

Breast cancer (BC) is the most common cancer in women and the leading cause of cancer-related death worldwide. This heterogeneous disease has been historically considered a non-immunogenic type of cancer. However, recent advances in immunotherapy have increased the interest in knowing the role of the immune checkpoints (IC) and other immune regulation pathways in this neoplasia.

METHODS

In this retrospective study, we evaluated the correlation of mRNA expression of CTLA-4, PDCD1 (PD1), CD274 (PD-L1), PDCD1LG2 (PD-L2), CD276 (B7-H3), JAK2, and FOXO1 with clinicopathological factors and BC patient's outcome by real-time quantitative polymerase chain reaction (qPCR).

RESULTS

Our results showed that immunoregulatory gene expression depends on BC immunophenotype being CTLA-4 and PDCD1 (PD1) overexpressed on triple-negative/basal-like (TN/BL) and luminal B/HER2-positive phenotypes, respectively, and CD276 (B7-H3), JAK2 and FOXO1 associated with both luminal A and luminal B/HER2-negative tumors. In addition, we found that these genes can also be related to aggressive and non-aggressive clinicopathological characteristics in BC. Finally, survival analysis showed that CTLA-4 expression levels emerge as a significant independent factor of good prognosis in BC patients, especially in the HER2-enriched subtype.

CONCLUSION

Considering all these data, we can conclude that the expression of immunoregulatory genes depends on tumor phenotype and has potential clinical implications in BC patients.

Virtual patient analysis identifies strategies to improve the performance of predictive biomarkers for PD-1 blockade

Patients with metastatic triple-negative breast cancer (TNBC) show variable responses to PD-1 inhibition. Efficient patient selection by predictive biomarkers would be desirable but is hindered by the limited performance of existing biomarkers. Here, we leveraged in silico patient cohorts generated using a quantitative systems pharmacology model of metastatic TNBC, informed by transcriptomic and clinical data, to explore potential ways to improve patient selection. We evaluated and quantified the performance of 90 biomarker candidates, including various cellular and molecular species, at different cutoffs by a cutoff-based biomarker testing algorithm combined with machine learning-based feature selection. Combinations of pretreatment biomarkers improved the specificity compared to single biomarkers at the cost of reduced sensitivity. On the other hand, early on-treatment biomarkers, such as the relative change in tumor diameter from baseline measured at two weeks after treatment initiation, achieved remarkably higher sensitivity and specificity. Further, blood-based biomarkers had a comparable ability to tumor- or lymph node-based biomarkers in identifying a subset of responders, potentially suggesting a less invasive way for patient selection.

Investigating tumor immunogenicity in breast cancer: deciphering the tumor immune response to enhance therapeutic approaches

The interplay between immune cells and malignant cells represents an essential chapter in the eradication of breast cancer. This widely distributed and diverse form of cancer represents a major threat to women worldwide. The incidence of breast cancer is related to several risk factors, notably genetic predisposition and family antecedents. Despite progress in treatment modalities varying from surgery and chemotherapy to radiotherapy and targeted therapies, persistently high rates of recurrence, metastasis, and treatment resistance underscore the urgent need for new therapeutic approaches. Immunotherapy has gained considerable ground in the treatment of breast cancer, as it takes advantage of the complex interactions within the tumor microenvironment. This dynamic interplay between immune and tumor cells has become a key point of focus in immunological research. This study investigates the role of various cancer markers, such as neoantigens and immune regulatory genes, in the diagnosis and treatment of breast tumors. Moreover, it explores the future potential of immune checkpoint inhibitors as therapeutically effective agents, as well as the challenges that prevent their efficacy, in particular tumor-induced immunosuppression and the difficulty of achieving tumor specificity.

PD-1 inhibitor sintilimab treated patients with metastatic triple-negative breast cancer

Purpose

Triple-negative breast cancer (TNBC) is a highly challenging subtype due to a unique tumor microenvironment. Several evidence (IMpassion130 trial and KEYNOTE-355 trial) supported the therapeutic effect of the immune checkpoint inhibitor in TNBC. However, the efficacy and safety of the PD-1 inhibitor sintilimab in breast cancer (BC) has not been well-investigated. So the real-world data on sintilimab-treated patients with metastatic BC were collected and analyzed in this study.

Methods

The patients were eligible according to the requirements included: ages between 18 years and 75 years; recurrent or metastatic TNBC; measurable disease based on RECIST v1.1; no limitation on the prior systemic treatments; and ECOG performance status of 0-1. Patients received sintilimab 200 mg intravenously every 3 weeks until unacceptable toxicity or disease progression.

Results

From 1 June 2019 to 1 October 2022, 40 female patients (median age, 55.5 years) with metastatic TNBC (mTNBC) were enrolled into the study. The median prior lines of systemic therapy for mTNBC was three (range, 1-8), with 60% of cases receiving at least three lines of therapy for metastatic disease. The visceral or brain metastasis was detected in 40.4% or 9.6% of patients, respectively. The median duration of response was 2.8 months (range, 0.7-21.0), and the median number of sintilimab doses administered was 4 (range, 1-30). The ORR and DCR were 22.5% and 72.5%, separately. The median PFS was 3.5 months (range, 1.4-21.0), with a 6-month PFS rate of 15.0% (6/40). The median OS was 52.5 months (range, 9.0-247.0) as of data cut-off. Common adverse effects were acceptable, and fatigue, skin rash, and pruritus were the frequent toxicity observed. Two cases of grade 3 curable adverse events were considered to be treatment-related. PD-L1-positive tumor was found in 40% cases (4/10) of mTNBC. Although statistical difference was not reached, the trend was obvious. Patients with PD-L1-positive tumor gained better treatment response, while the TMB-high carrier received more benefits of PFS and OS.

Conclusion

In our study, preliminary evidence provided the anticancer activity and acceptable adverse effects of sintilimab administered every 3 weeks to pretreated patients with mTNBC. Sintilimab showed its efficacy and safety of immunotherapy for patients with advanced TNBC.

Narrative review on efficacy and safety of anti-angiogenesis in combination with immunotherapy in the treatment of breast cancer

Background and Objective

Breast cancer was the second frequently diagnosed cancer in 2022 among all cancers. Besides classical chemotherapy and radiation, immunotherapy and targeted therapy are both identical treatment options for patients with advanced breast cancer. Immunotherapy is a therapeutic approach to control and eliminate tumors by restarting and maintaining the tumor-immunity cycle and restoring the body's normal anti-tumor immune response. Immunotherapy alone or in combination with other therapies has been shown to be clinically beneficial in a variety of solid tumors with a manageable safety profile. However, immunotherapy alone cannot fully satisfy the therapeutic needs for patients with breast cancer. Therefore, there is an urgent need for immunotherapy to be combined with other therapeutic approaches to increase treatment efficacy.

Methods

We systematically searched PubMed database for relevant studies published over the past 5 years. Articles were screened for eligibility and key data extracted.

Key Content and Findings

We assess the current breast cancer treatment landscape, summarizing efficacy and safety of recent immunotherapy, chemotherapy combined with immunotherapy, immunotherapy combined with anti-angiogenic therapy. In the treatment of breast cancer, aiming to promote further research and applications of this novel treatment regimen in patients with breast cancer. Since anti-angiogenic therapy can reprogramme the tumor immune microenvironment, immunotherapy in combination with anti-angiogenic therapy might have a synergistic effect, igniting a new hope for immunotherapy for breast cancer patients. The review's conclusions offer insightful information on the state of breast cancer treatment today. In the end, improving clinical practice and pertinent research for immunotherapy combination therapy will contribute to bettering patient outcomes, raising quality of life, and creating more potent treatments.

Conclusions

This review emphasizes the potential of immunotherapy combinations, especially with anti-angiogenic therapeutic regimens, as a viable strategy for the treatment of breast cancer through a thorough study of the literature. To improve treatment approaches, lessen side effects for patients, and find trustworthy biomarkers to forecast response to immunotherapy combo medicines, further research is necessary.

PD-L1 expression and tumor-infiltrating lymphocytes: Correlations and prognostic values in Chinese triple-negative breast cancer patients with different molecular subtyping

OBJECTIVE

To investigate the correlation between programmed death ligand-1 (PD-L1) expression and tumor-infiltrating lymphocytes (TILs) and evaluate the prognostic value of PD-L1 and TILs in Chinese triple-negative breast cancer (TNBC) patients with different molecular subtype METHODS: This retrospective study was conducted at 2020. Specifically, the pre-chemotherapy clinical data and non-stained tissue blocks of 465 TNBC patients visited the Fudan University Shanghai Cancer Center (FUSCC) between 2008 and 2014 were collected, with their blocks sliced and stained using PD-L1(SP142), and the outcome of subsequent chemotherapy obtained in 2020. The relapse-free survival (RFS) of the study population was calculated. The baseline PD-L1 expression status correlations with TILs and molecular subtypes were assessed using Spearman's rank correlation analysis and the Kruskal-Wallis test. Kaplan-Meier survival analyses were undertaken to evaluate the prognosis value of TILs and PD-L1 expression.

RESULTS

PD-L1 expression status on IC was moderately and positively correlated with stromal tumor-infiltrating lymphocytes (sTILs) (rs = 0.502, P <0.001) and iTILs (rs = 0.410, P < 0.001), respectively. PD-L1 expression status and TILs showed significant differences among molecular subtypes (P < 0.001), with the highest proportion of PD-L1+ and high TILs patients observed in the immunomodulatory (IM) subtype. TILs were significantly associated with RFS. Moreover, sTILs could act as an independent predictor of RFS (RR 0.953, 95 % CI 0.920 ∼ 0.987, P = 0.007), while PD-L1 expression status did not show the same prognostic significance.

CONCLUSIONS

The incorporation of pre-treatment TILs and PD-L1 expression status as valuable tools for optimizing patient selection for immunotherapy and managing the risks associated with chemotherapy in Chinese TNBC patients.

DATA AVAILABILITY

The data sets generated and analyzed during the current study are available from the corresponding author.

Window of opportunity trials with immune checkpoint inhibitors in triple-negative breast cancer

Patients with triple-negative breast cancer (TNBC) have a relatively poor clinical outcome. The immune checkpoint inhibitor (ICI) pembrolizumab combined with chemotherapy is the current standard of care in TNBC patients with stage II and III. Monotherapy with ICIs has not been comprehensively assessed in the neoadjuvant setting in TNBC patients, given unfavorable results in metastatic trials. ICIs, however, have been tested in the window of opportunity (WOO) before surgery or standard chemotherapy-based neoadjuvant treatment. The WOO design is well suited to assess an ICI alone or in combination with other ICIs, targeted therapy, radiotherapy or cryotherapy, and measure their pharmacodynamic and clinical effect in this treatment-naive population. Some patients show a good response to ICIs in WOO studies. Biomarkers like tumor-infiltrating lymphocytes, programmed death ligand-1, and interferon-γ signature may predict activity and may identify patients likely to benefit from ICIs. Moreover, an increase in tumor-infiltrating lymphocytes, programmed death ligand-1 expression or T cell receptor expansion following administration of ICIs in the WOO setting could potentially inform of immunotherapy benefit, which would allow tailoring further treatment. This article reviews WOO trials that assessed immunotherapy in the early-stage TNBC population, and how these results could be translated to test de-escalation strategies of neoadjuvant chemotherapy and immunotherapy without compromising a patient's prognosis.

Caspase-1-dependent spatiality in triple-negative breast cancer and response to immunotherapy

Tumor immune microenvironment (TIME) spatial organization predicts outcome and therapy response in triple-negative breast cancer (TNBC). An immunosuppressive TIME containing elevated tumor-associated macrophages (TAM) and scarce CD8+ T cells is associated with poor outcome, but the regulatory mechanisms are poorly understood. Here we show that ETS1-driven caspase-1 expression, required for IL1β processing and TAM recruitment, is negatively regulated by estrogen receptors alpha (ERα) and a defining feature of TNBC. Elevated tumoral caspase-1 is associated with a distinct TIME characterized by increased pro-tumoral TAMs and CD8+ T cell exclusion from tumor nests. Mouse models prove the functional importance of ERα, ETS1, caspase-1 and IL1β in TIME conformation. Caspase-1 inhibition induces an immunoreactive TIME and reverses resistance to immune checkpoint blockade, identifying a therapeutically targetable mechanism that governs TNBC spatial organization.

Present and Future of Immunotherapy for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) lacks the expression of estrogen receptors (ERs), human epidermal growth factor receptor 2 (HER2), and progesterone receptors (PRs). TNBC has the poorest prognosis among breast cancer subtypes and is more likely to respond to immunotherapy due to its higher expression of PD-L1 and a greater percentage of tumor-infiltrating lymphocytes. Immunotherapy has revolutionized TNBC treatment, especially with the FDA's approval of pembrolizumab (Keytruda) combined with chemotherapy for advanced cases, opening new avenues for treating this deadly disease. Although immunotherapy can significantly improve patient outcomes in a subset of patients, achieving the desired response rate for all remains an unmet clinical goal. Strategies that enhance responses to immune checkpoint blockade, including combining immunotherapy with chemotherapy, molecularly targeted therapy, or radiotherapy, may improve response rates and clinical outcomes. In this review, we provide a short background on TNBC and immunotherapy and explore the different types of immunotherapy strategies that are currently being evaluated in TNBC. Additionally, we review why combination strategies may be beneficial, provide an overview of the combination strategies, and discuss the novel immunotherapeutic opportunities that may be approved in the near future for TNBC.

PARP inhibition with rucaparib alone followed by combination with atezolizumab: Phase Ib COUPLET clinical study in advanced gynaecological and triple-negative breast cancers

BACKGROUND

Combining PARP inhibitors (PARPis) with immune checkpoint inhibitors may improve clinical outcomes in selected cancers. We evaluated rucaparib and atezolizumab in advanced gynaecological or triple-negative breast cancer (TNBC).

METHODS

After identifying the recommended dose, patients with PARPi-naive BRCA-mutated or homologous recombination-deficient/loss-of-heterozygosity-high platinum-sensitive ovarian cancer or TNBC received rucaparib plus atezolizumab. Tumour biopsies were collected pre-treatment, during single-agent rucaparib run-in, and after starting combination therapy.

RESULTS

The most common adverse events with rucaparib 600 mg twice daily and atezolizumab 1200 mg on Day 1 every 3 weeks were gastrointestinal effects, fatigue, liver enzyme elevations, and anaemia. Responding patients typically had BRCA-mutated tumours and higher pre-treatment tumour levels of PD-L1 and CD8 + T cells. Markers of DNA damage repair decreased during rucaparib run-in and combination treatment in responders, but typically increased in non-responders. Apoptosis signature expression showed the reverse. CD8 + T-cell activity and STING pathway activation increased during rucaparib run-in, increasing further with atezolizumab.

CONCLUSIONS

In this small study, rucaparib plus atezolizumab demonstrated acceptable safety and activity in BRCA-mutated tumours. Increasing anti-tumour immunity and inflammation might be a key mechanism of action for clinical benefit from the combination, potentially guiding more targeted development of such regimens.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov (NCT03101280).

Eganelisib combined with immune checkpoint inhibitor therapy and chemotherapy in frontline metastatic triple-negative breast cancer triggers macrophage reprogramming, immune activation and extracellular matrix reorganization in the tumor microenvironment

BACKGROUND

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with a poor prognosis particularly in the metastatic setting. Treatments with anti-programmed cell death protein-1/programmed death-ligand 1 (PD-L1) immune checkpoint inhibitors (ICI) in combination with chemotherapies have demonstrated promising clinical benefit in metastatic TNBC (mTNBC) but there is still an unmet need, particularly for patients with PD-L1 negative tumors. Mechanisms of resistance to ICIs in mTNBC include the presence of immunosuppressive tumor-associated macrophages (TAMs) in the tumor microenvironment (TME). Eganelisib is a potent and selective, small molecule PI3K-γ inhibitor that was shown in preclinical studies to reshape the TME by reducing myeloid cell recruitment to tumors and reprogramming TAMs from an immune-suppressive to an immune-activating phenotype and enhancing activity of ICIs. These studies provided rationale for the clinical evaluation of eganelisib in combination with the anti-PD-L1 atezolizumab and nab-paclitaxel in firstline mTNBC in the phase 2 clinical trial MAcrophage Reprogramming in Immuno-Oncology-3 (MARIO-3, NCT03961698). We present here for the first time, in-depth translational analyses from the MARIO-3 study and supplemental data from eganelisib monotherapy Ph1/b study in solid tumors (MARIO-1, NCT02637531).

METHODS

Paired pre-treatment and post-treatment tumor biopsies were analyzed for immunophenotyping by multiplex immunofluorescence (n=11), spatial transcriptomics using GeoMx digital spatial profiling (n=12), and PD-L1 immunohistochemistry, (n=18). Peripheral blood samples were analyzed using flow cytometry and multiplex cytokine analysis.

RESULTS

Results from paired tumor biopsies from MARIO-3 revealed gene signatures of TAM reprogramming, immune activation and extracellular matrix (ECM) reorganization. Analysis of PD-L1 negative tumors revealed elevated ECM gene signatures at baseline that decreased after treatment. Gene signatures of immune activation were observed regardless of baseline PD-L1 status and occurred in patients having longer progression-free survival. Peripheral blood analyses revealed systemic immune activation.

CONCLUSIONS

This is the first report of translational analyses including paired tumor biopsies from a phase 2 clinical study of the first-in-class PI3K-γ inhibitor eganelisib in combination with atezolizumab and nab-paclitaxel in frontline mTNBC. These results support the mechanism of action of eganelisib as a TAM-reprogramming immunotherapy and support the rationale for combining eganelisib with ICI and chemotherapy in indications with TAM-driven resistance to ICI.

Upregulation of collagen type X alpha 1 promotes the progress of triple-negative breast cancer via Wnt/β-catenin signaling

Triple-negative breast cancer (TNBC) is a malignant tumor with high degree of malignancy and lack of effective target treatment. The research aims to explore the role and mechanism of X collagen alpha-1 chain protein (COL10A1 gene) in TNBC. UALCAN and Kaplan-Meier were used to detect the expression of COL10A1 and its role in the prognosis of breast cancer patients. The cells with stably expressing high levels of COL10A1 were obtained by recombinant lentivirus infection. The expression of COL10A1 in cells was temporarily downregulated by siRNA interference fragments. Real-time quantitative polymerase chain reaction and western blot analysis were utilized to detect the changes of COL10A1 mRNA and protein expression. The biological functions of the cells were evaluated by colony formation, cell counting kit-8, cell invasion and wound healing experiments. In addition, the effect of COL10A1 on angiogenesis was investigated by tube formation assay. Xenograft tumor model was used to confirm the effect of COL10A1 on tumorigenicity in vivo and multiplex fluorescent immunohistochemistry to detect multiple proteins simultaneously. The possible molecular mechanism of the function of COL10A1 was speculated through the detection of proteins in functionally related pathways. COL10A1 is highly expressed and is significantly associated with worse overall survival (OS) and recurrence-free survival (RFS) in TNBC. Overexpression of COL10A1 increased the clone formation rate and cell migration capacity of TNBC cells. In the COL10A1 overexpression group, the clone formation rates of MD-MB-231 and BT-549 cells (21.5 ± 0.62, 27.83 ± 3.72)% were significantly higher than those in the control group(15.23 ± 2.79, 19.4 ± 1.47)%, and the relative migration ratio (47.40 ± 3.09, 41.26 ± 4.33)% were higher than those in the control group (34.48 ± 2.03, 21.80 ± 1.03)%. When the expression of COL10A1 was downregulated, the ability of clone formation and wound-healing migration capacity in TNBC cells was weakened. Upregulated COL10A1 in TNBC cells generated more junctions and longer total segments between vascular endothelial cells, and promoted angiogenesis of the cells, and thus enhanced the tumorigenesis. In TNBC, it was found that COL10A1 might affect epithelial-mesenchymal transition (EMT) of the cells through Wnt/β-catenin signaling pathway by the detection of the related pathway proteins. COL10A1 is highly expressed in TNBC, and its high expression leads to poor OS and RFS. COL10A1 may enhance TNBC cell proliferation, migration and tumor-related angiogenesis, and promote tumorigenesis in vivo via Wnt/β-catenin signaling.

CXCR6 expression correlates with radiotherapy response and immune context in triple-negative breast cancer-experimental studies

BACKGROUND

The chemokine receptor CXCR6 is critical for sustained tumor control mediated by CD8+ cytotoxic T cells (CTLs) in tumors. Previous studies have shown that ionizing radiation induces an inflamed immune contexture by upregulating CXCR6. However, the clinical significance of CXCR6 expression in triple-negative breast cancer (TNBC) and its correlation with radiotherapy remains unknown. This study aimed to clarify the prognostic value of CXCR6 and its role in the breast tumor microenvironment (TME).

METHODS

The messenger RNA and protein expression of CXCR6 in human TNBC and their association with survival were analyzed. The role of CXCR6 in the immune context was investigated using a combination of single-cell RNA sequencing, bulk transcriptome sequencing data, and fluorescence-based multiplex immunohistochemistry (mIHC) techniques.

RESULTS

Elevated CXCR6 expression correlated with better clinical outcomes and superior response to adjuvant radiotherapy and immunotherapy in TNBC. CXCR6 fostered an immunostimulatory microenvironment characterized by upregulated cytotoxic markers. We also found that CXCR6 plays a crucial role in regulating the differentiation of CD8+ T cells and the intercellular communication of immune cell subtypes, thus shaping the TME.

CONCLUSIONS

This study highlights the emerging role of CXCR6 in shaping the TME and targeting CXCR6 may be a promising strategy for improving the effectiveness of radiotherapy and immunotherapy in TNBC.

Towards targeting the breast cancer immune microenvironment

The tumour immune microenvironment is shaped by the crosstalk between cancer cells, immune cells, fibroblasts, endothelial cells and other stromal components. Although the immune tumour microenvironment (TME) serves as a source of therapeutic targets, it is also considered a friend or foe to tumour-directed therapies. This is readily illustrated by the importance of T cells in triple-negative breast cancer (TNBC), culminating in the advent of immune checkpoint therapy in combination with cytotoxic chemotherapy as standard of care for both early and advanced-stage TNBC, as well as recent promising signs of efficacy in a subset of hormone receptor-positive disease. In this Review, we discuss the various components of the immune TME in breast cancer and therapies that target or impact the immune TME, as well as the complexity of host physiology.

Tumor necrosis factor receptor 2 promotes endothelial cell-mediated suppression of CD8+ T cells through tuning glycolysis in chemoresistance of breast cancer

BACKGROUND

T cells play a pivotal role in chemotherapy-triggered anti-tumor effects. Emerging evidence underscores the link between impaired anti-tumor immune responses and resistance to paclitaxel therapy in triple-negative breast cancer (TNBC). Tumor-related endothelial cells (ECs) have potential immunoregulatory activity. However, how ECs regulate T cell activity during TNBC chemotherapy remains poorly understood.

METHODS

Single-cell analysis of ECs in patients with TNBC receiving paclitaxel therapy was performed using an accessible single-cell RNA sequencing (scRNA-seq) dataset to identify key EC subtypes and their immune characteristics. An integrated analysis of a tumor-bearing mouse model, immunofluorescence, and a spatial transcriptome dataset revealed the spatial relationship between ECs, especially Tumor necrosis factor receptor (TNFR) 2+ ECs, and CD8+ T cells. RNA sequencing, CD8+ T cell proliferation assays, flow cytometry, and bioinformatic analyses were performed to explore the immunosuppressive function of TNFR2 in ECs. The downstream metabolic mechanism of TNFR2 was further investigated using RNA sequencing, cellular glycolysis assays, and western blotting.

RESULTS

In this study, we identified an immunoregulatory EC subtype, characterized by enhanced TNFR2 expression in non-responders. By a mouse model of TNBC, we revealed a dynamic reduction in the proportion of the CD8+ T cell-contacting tumor vessels that could co-localize spatially with CD8+ T cells during chemotherapy and an increased expression of TNFR2 by ECs. TNFR2 suppresses glycolytic activity in ECs by activating NF-κB signaling in vitro. Tuning endothelial glycolysis enhances programmed death-ligand (PD-L) 1-dependent inhibitory capacity, thereby inducing CD8+ T cell suppression. In addition, TNFR2+ ECs showed a greater spatial affinity for exhausted CD8+ T cells than for non-exhausted CD8+ T cells. TNFR2 blockade restores impaired anti-tumor immunity in vivo, leading to the loss of PD-L1 expression by ECs and enhancement of CD8+ T cell infiltration into the tumors.

CONCLUSIONS

These findings reveal the suppression of CD8+ T cells by ECs in chemoresistance and indicate the critical role of TNFR2 in driving the immunosuppressive capacity of ECs via tuning glycolysis. Targeting endothelial TNFR2 may serve as a potent strategy for treating TNBC with paclitaxel.