Durvalumab with olaparib and paclitaxel for high-risk HER2-negative stage II/III breast cancer: Results from the adaptively randomized I-SPY2 trial

The Identification of Novel Prognostic and Predictive Biomarkers in Breast Cancer via the Elucidation of Tumor Ecotypes Using Ecotyper

Background

Breast cancer is a highly heterogeneous disease, characterized by tumor and nontumor cells at various cell states. Ecotyper is an innovative machine learning framework that quantifies the tumor microenvironment and delineates the tumor ecosystem, demonstrating clinical significance. However, further validation is needed in breast cancer.

Methods

Ecotyper was applied to identify multiple cellular states and tumor ecotypes using large-scale breast cancer bulk sequencing data, followed by a detailed analysis of their associations with clinical classification, molecular subtypes, survival prognosis, and immunotherapy response. Identified subtypes were further characterized using single-cell and spatial data sets to reveal molecular profiles.

Results

In a comprehensive analysis of 6578 breast cancer samples from four data sets, Ecotyper identified 69 cellular states and 10 tumor ecotypes. Of these, 37 cellular states significantly correlated with overall survival. Notably, specific states within epithelial cells, macrophages/monocytes, and fibroblasts were linked to a worse prognosis. CE2 abundance was identified as the most significant marker indicating unfavorable prognosis and was further validated in an additional data set of 116 HER2-negative patients. These biomarkers also indicated the efficacy of neoadjuvant immunotherapy in breast cancer. CE2-high cancers were characterized by an abundance of basal-like epithelial cells, scant lymphocytic infiltration, and activation of hypoxia signaling. Single-cell analysis showed that CE2-high areas were rich in SPP1-positive tumor-associated macrophages(TAM), basal-like epithelial cells, and hypoxic cancer-associated fibroblasts(CAF). Spatially, these regions were often peripheral in triple-negative breast cancer, adjacent to fibrotic/necrotic zones. Multiplex immunofluorescence confirmed the enrichment of SPP1+CD68+TAM and HIF1A+SMA+CAF in hypoxic triple-negative breast cancer (TNBC) regions.

Conclusions

Ecotyper identified novel biomarkers for breast cancer prognosis and treatment prediction. The CE2-high region may represent a hypoxic immune-suppressive niche.

The role of ferroptosis in breast cancer: Tumor progression, immune microenvironment interactions and therapeutic interventions

Ferroptosis represents a distinctive and distinct form of regulated cellular death, which is driven by the accumulation of lipid peroxidation. It is distinguished by altered redox lipid metabolism and is linked to a spectrum of cellular activities, including cancer. In breast cancer (BC), with triple negative breast cancer (TNBC) being an iron-and lipid-rich tumor, inducing ferroptosis was thought to be a novel approach to killing breast tumor cells. However, in the recent past, a novel conceptual framework has emerged which posits that in addition to the promotion of tumor cell death, ferritin deposition has a potent immunosuppressive effect on the tumor immune microenvironment (TIME) via the influence on both innate and adaptive immune responses. TIME of BC includes various cell populations from both the innate and adaptive immune systems. In this review, the internal association between iron homeostasis and the progression of ferroptosis, along with the common inducers and protectors of ferroptosis in BC, are discussed in detail. Furthermore, a comprehensive analysis is conducted on the dual role of ferroptosis in immune cells and proto-oncogenic functions, along with an evaluation of the potential applications of immunogenic cell death-targeted immunotherapy in TIME of BC. It is anticipated that our review will inform future research endeavors that seek to integrate ferroptosis and immunotherapy in the management of BC.

Immunotherapy in Triple-Negative Breast Cancer

Currently, immunotherapy has led to a paradigmatic shift in the treatment of many cancer types, including triple-negative breast cancer. Immunotherapy increases the efficacy of the immune system in treating cancer, with a durable effect due to immunologic memory. The PD-1 inhibitor, pembrolizumab, combined with neoadjuvant chemotherapy, improved event-free survival and is a new standard of care for patients with high-risk, early stage triple-negative breast cancer (TNBC), regardless of tumor PD-L1 expression. For metastatic TNBC, pembrolizumab combined with chemotherapy is a new standard of care for first-line therapy for PD-L1+ metastatic TNBC, and it improves overall survival. The PD-L1 inhibitor, atezolizumab, combined with nab-paclitaxel, is also approved for first-line treatment of metastatic PD-L1+ TNBC. The aim of this review is to examine the existing evidence and ongoing studies on immunotherapy in patients with early stage and metastatic triple-negative breast cancer (TNBC), including new combination strategies with several drugs, such as chemotherapy, targeted therapy, or radiation and to discuss immune checkpoint inhibitor (ICI) applications and the possibility of emerging strategies in different TNBC stages.

Immunotherapy in primary hormone-receptor positive breast cancer: A systematic review

Hormone-receptor positive (HR+), HER2 negative breast cancer (BC) is considered immunologically silent, thus investigation of immunotherapy in this subtype has evolved slower. This systematic review offers an overview of the clinical trials investigating the safety and efficacy of ICI in primary HR+/HER2- BC. Literature search was conducted up to October 30, 2022 to identify immunotherapy trials with checkpoint inhibitors in non-metastatic HR+/HER2- breast cancer. 39 trials were identified, mainly in early-phase clinical trials. None of the trials investigate ICI monotherapy and only 2 Phase 3 clinical trials are ongoing. Most trials investigate the use of ICI in the neoadjuvant setting in combination with chemotherapy. 18 trials have reported results and 6 of them efficacy results specifically for HR+/HER2- BC. ICI could be a promising therapeutic strategy for HR+/HER2- BC, however clinical benefit is restricted to subgroups of patients, depending on tumor molecular profile.

APOL6 as a potential biomarker of immuno-correlation and therapeutic prediction in cancer immunotherapy

The emergence of immune checkpoint inhibitors (ICIs) has significantly revolutionized the approach to treating advanced cancers. Despite their remarkable efficacy, not all patients exhibit favorable responses to ICI therapy. Hence, more biomarkers for therapeutic prediction need to be discovered. In this study, we utilized public cohorts to investigate the predictive significance and immunological associations of apolipoprotein L6 (APOL6) in cancers. The expression of APOL6 was found to be enhanced in tumors of patients who exhibited strong immunotherapeutic responses across various types of cancer. Furthermore, APOL6 showed immune correlations in pan-cancer and was confirmed by the tissue microarray cohort and in vitro experiments. Overall, this study highlights that APOL6 serves as a beneficial biomarker for immune checkpoint inhibitors in patients with cancer. Additional research involving larger numbers of patients and the underlying mechanism is necessary to determine its effectiveness as a biomarker for predicting the benefits of ICIs.

Novel clinical potential of poly (ADP‑ribose) polymerase inhibitors in triple‑negative breast cancer: Mechanistic insights and clinical applications (Review)

Breast cancer is one of the most prevalent malignant tumors worldwide, and triple-negative breast cancer (TNBC) presents a major therapeutic challenge due to the lack of effective targeted treatment options. Poly (ADP-ribose) polymerase (PARP) plays a critical role in DNA damage repair, and its inhibitors have shown significant therapeutic efficacy in patients with TNBC exhibiting breast cancer susceptibility gene (BRCA) mutations. The present review aimed to analyze the molecular mechanisms of cell death induced by DNA damage related to PAR and PARP, thoroughly exploring the role of PARP in regulatory pathways. Additionally, it intended to highlight clinical trials and therapeutic outcomes of PARP inhibitors currently used in TNBC treatment. In particular, the current review delves into the mechanisms of drug resistance, such as BRCA mutation reversion and PARP protein trapping, and examines potential strategies to overcome PARP inhibitor resistance in the future. Ultimately, the present study aims to offer novel perspectives and research directions for further optimizing the application of PARP inhibitors in TNBC therapy.

PARP Inhibitors in the Neoadjuvant Setting; A Comprehensive Overview of the Rationale for their Use, Past and Ongoing Clinical Trials

PURPOSEOF REVIEW

Poly (ADP-ribose) polymerases (PARPs) are enzymes essential for detecting and repairing DNA damage through poly-ADP-ribosylation. In cancer, cells with deficiencies in homologous recombination repair mechanisms often become more dependent on PARP-mediated repair mechanisms to effectively repair dsDNA breaks. As such, PARP inhibitors (PARPis) were introduced into clinical practice, serving as a key targeted therapy option through synthetic lethality in the treatment of cancers with homologous recombination repair deficiency (HRD). Though PARPis are currently approved in the adjuvant setting for several cancer types such as ovarian, breast, prostate and pancreatic cancer, their potential role in the neoadjuvant setting remains under investigation. This review outlines the rationale for using PARPi in the neoadjuvant setting and evaluates findings from early and ongoing clinical trials.

RECENT FINDINGS

Our analysis indicates that numerous studies have explored PARPi as a neoadjuvant treatment for HRD-related cancers. The majority of neoadjuvant PARPi trials have been performed in breast and ovarian cancer, while phase II/III evidence supporting efficacy in prostate and pancreatic cancers remains limited. Studies are investigating PARPi in the neoadjuvant setting of HRD-related cancers. Future research should prioritize combination strategies with immune checkpoint inhibitors and expand outcome measures to include patient satisfaction and quality-of-life metrics.

Inhibiting glycolysis facilitated checkpoint blockade therapy for triple-negative breast cancer

Cancer cells are characterized by their altered energy metabolism. A hallmark of cancer metabolism is aerobic glycolysis, also called the Warburg effect. Hexokinase 2 (HK2), a crucial glycolytic enzyme converting glucose to glucose-6-phosphate, has been identified as a central player in the Warburg effect. Deletion of HK2 decreases cancer cell proliferation in animal models without explicit side effects, suggesting that targeting HK2 is a promising strategy for cancer therapy. In this study, we discovered a correlation between HK2 and the tumor immune response in triple-negative breast cancer. Inhibition of HK2 led to a reduction in G-CSF expression in 4T1 cells and a decrease in the development of myeloid-derived suppressor cells which, in turn, enhanced T cell immunity and prolonged the survival of 4T1 tumor-bearing mice. Furthermore, the HK2 inhibitor 3-BrPA improved the therapeutic efficacy of anti-PD-L1 therapy in 4T1 tumor-bearing mouse models. This study highlights the potential of glycolysis-targeting interventions as a novel treatment strategy, which can be combined with immunotherapy for the treatment of triple-negative breast cancer.

Current Status of Breast Cancer Immunotherapy and Prognosis-Related Markers

Breast cancer, being the most common type of cancer globally, stands out as the primary malignant tumor affecting females. With the advent of breast cancer immunotherapy, inhibitors targeting immune checkpoints such as anti-PD-1 (Programmed cell death protein 1) / PD-L1 (Programmed cell death-Ligand 1) and CTLA-4 (Cytotoxic T Lymphocyte-Associated Antigen-4) have demonstrated promising outcomes for breast cancer patients across all molecular subtypes, particularly those with advanced breast cancer and triple-negative breast cancer (TNBC). Our current focus lies in accurately predicting the prognosis of breast cancer patients and the effectiveness of immunotherapy. This article provides a review of emerging biomarkers for breast cancer, encompassing immune-related markers, metabolic indicators, and potential prognosis-related markers. The primary emphasis of the article is to review immune-related tumor biomarkers in breast cancer. Our goal is to summarize relevant studies capable of forecasting breast cancer prognosis and immunotherapy effectiveness. Lastly, we delve into the future directions of breast cancer immunotherapy development.

Recent Advances in Immune Checkpoint Inhibitors for Triple-Negative Breast Cancer

While immunotherapy has transformed treatment across various cancers, its impact on breast cancer is relatively limited. Recent advances have established immunotherapy as an effective approach for triple-negative breast cancer (TNBC), an aggressive subtype with limited therapeutic targets and poor prognosis. Specifically, pembrolizumab, an immune checkpoint inhibitor (ICI), is now approved for both first-line metastatic and early-stage TNBC. In metastatic TNBC, combining ICIs with chemotherapy, particularly pembrolizumab, has demonstrated survival benefits in patients with PD-L1-positive disease. However, extending these benefits to broader populations has proven challenging, highlighting the need for better patient selection and novel strategies. Emerging approaches include combining ICIs with antibody-drug conjugates, PARP inhibitors, dual ICIs, and bispecific antibodies targeting angiogenesis and immune checkpoints. These strategies aim to overcome resistance and expand immunotherapy's efficacy beyond the PD-1/PD-L1 pathway. In early-stage disease, pembrolizumab combined with chemotherapy in the neoadjuvant setting has significantly improved pathologic complete response, event-free survival, and overall survival, establishing a new standard of care. Ongoing research aims to determine the optimal timing for ICI administration, explore less toxic chemotherapy backbones, utilize biomarkers for personalized treatment, and assess whether adding complementary treatments, such as radiation therapy for high-risk cases, can improve outcomes. This review examines the successes and setbacks of ICI use in TNBC, offering a comprehensive overview of current practices and future directions. It emphasizes optimizing ICI timing, leveraging biomarkers, and integrating novel agents to refine treatment approaches for both metastatic and early-stage TNBC. As immunotherapy continues to evolve, future research must address the unmet needs of this challenging breast cancer subtype, offering hope for improved outcomes.

The Crosstalk with CXCL10-Rich Tumor-Associated Mast Cells Fuels Pancreatic Cancer Progression and Immune Escape

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease, necessitating approaches to improve prognosis. As the mediator of allergic process, mast cells have been found in various cancers and are associated with survival. However, the biological behaviors of tumor-associated mast cells (TAMCs) remain unclear. Herein, an excessive infiltration of TAMCs in PDAC is demonstrated, which apparently associated with poor survival in PDAC patients. PDAC cells are found to recruit CXCR2+ MCs into TME, and then inhibited MCs ferroptosis, and maintained their proliferation. Concomitantly, the tumor-derived exosome miR-188-5p activated the PTEN/AKT/GSK3β signaling, further stabilized transcriptional factor ERG by inhibiting its ubiquitin degradation, and finally enhanced the transcription of cxcl10 within TAMCs. In reverse, TAMCs-derived CXCL10 reversely promoted tumor epithelial-mesenchymal transition and induced immunosuppressive tumor microenvironment by recruiting CXCR3+ Tregs. Sodium cromoglycate (SCG) is a membrane stabilizer for MCs and confirmed as an effective and widely used agent to block TAMCs-derived CXCL10 and further sensitize the therapeutic efficacy of anti-PD-1 antibody plus gemcitabine for PDAC. These findings illuminate a critical and innovative crosstalk between TAMCs and PDAC cells that promote PDAC progression, and SCG sensitizes PDAC to the current immuno-chemotherapy, which reveals its potential to be a valuable adjuvant for PDAC patients.

Artificial intelligence predicts multiclass molecular signatures and subtypes directly from breast cancer histology: a multicenter retrospective study

Detection of biomarkers of breast cancer incurs additional costs and tissue burden. We propose a deep learning-based algorithm (BBMIL) to predict classical biomarkers, immunotherapy-associated gene signatures, and prognosis-associated subtypes directly from hematoxylin and eosin stained histopathology images. BBMIL showed the best performance among comparative algorithms on the prediction of classical biomarkers, immunotherapy related gene signatures, and subtypes.

Tumor-stroma proportion is associated with increased M2 macrophage abundance and predicts the resistance to immune checkpoint blockade in breast cancer

BACKGROUND

The tumor stroma has been reported to be associated with worse prognosis in several solid tumors, but its prognostic value in breast cancer (BRCA) is still undefined.

METHODS

In this research, multiple public and in-house patient cohorts were collected to demonstrate the clinical and immune correlations of tumor-stroma proportion (TSP) in BRCA. In addition, in vitro assays uncovered the oncogenic role of TSP-related collagen in BRCA.

RESULTS

High TSP status based on hematoxylin and eosin (HE) staining was associated with positive hormone receptor status, advanced clinical stages, and poor immune checkpoint blockade (ICB) response. In addition, we developed a RNA-sequencing (RNA-seq)-based stromal score based on four critical genes expression (AEBP1, COL6A3, CTSK, and PLAC9). Both TSP status and stromal score were positively associated with increased M2 macrophage abundance in BRCA. Moreover, tumor collagen has been found to be enriched in samples with the high TSP status, and collagen promoted BRCA cells aggressiveness and macrophage M2 polarization.

CONCLUSIONS

The tumor stroma was found to be notably related to poor ICB response in patients with BRCA as a result of tumor stroma-macrophage interactions. Thus, the TSP status could predict the clinical outcomes of BRCA patients receiving ICB therapy.

Circadian Rhythm Disruption in Triple-Negative Breast Cancer: Molecular Insights and Treatment Strategies

Disruption of the circadian clock has been closely linked to the initiation, development, and progression of cancer. This study aims to explore the impact of circadian rhythm disruption (CRD) on triple-negative breast cancer (TNBC). We analyzed bulk and single-cell RNA sequencing data to assess circadian rhythm status in TNBC using multiple bioinformatic tools, alongside metabolomic profiles and tumor microenvironment evaluations to understand the influence of CRD on metabolic reprogramming and immune evasion. The results indicate that TNBC experiences profound CRD. Patients with a higher CRDscore exhibit significantly poorer relapse-free survival compared to those with a lower CRDscore. Cyclic ordering by periodic structure (CYCLOPS) identified significant changes in rhythmic gene expression patterns between TNBC and normal tissues, with TNBC showing a "rush hour" effect, where peak expression times are concentrated within specific time windows. Transcripts with disrupted circadian rhythms in TNBC were found to be involved in key pathways related to cell cycle regulation, metabolism, and immune response. Metabolomic analysis further revealed that TNBCs with high CRDscore are enriched in carbohydrate and amino acid metabolism pathways, notably showing upregulation of tryptophan metabolism. High CRDscore was also linked to an immunosuppressive tumor microenvironment, characterized by reduced immune cell infiltration, exhausted CD8+ T cells, and a diminished response to immune checkpoint blockade therapy. These findings suggest that the disrupted molecular clock in TNBC may activate tryptophan metabolism, thereby promoting immune evasion and potentially reducing the effectiveness of immunotherapy.

Immunotherapy and its racial specificity for breast cancer treatment in Asia: a narrative review

Immunotherapy, including immune checkpoint inhibitors, adoptive cell therapy, cancer vaccines, and other modalities, represents a significant advancement in cancer treatment. Breast cancer, traditionally considered less amenable to immunotherapy, has demonstrated responsiveness to immunotherapy when combined with conventional treatment options. These integrative strategies enhance the effectiveness of immunotherapy, bringing hope to patients. Furthermore, precision therapies guided by predictive biomarkers refine the scope of breast cancer immunotherapy and broaden its advantages. Notably, it is essential to recognise the differences in breast cancer epidemiology, clinical outcomes, and molecular signatures between Asian populations and those in Europe and North America. These include a higher proportion of premenopausal patients and variation in subtype distribution and gene mutation profiles, underscoring the importance of considering racial specificity in immunotherapy. Clinical efforts in Asia, supported by ethnicity-specific studies, indigenous immunotherapeutic agents, and precision medicine informed by predictive biomarkers, provide tailored treatment options. This review aims to present an overview of breast cancer immunotherapy while address the racial specificity to inform its application for Asian patients.

Beyond failure of endocrine-based therapies in HR+/HER2 negative advanced breast cancer: What before chemotherapy? A glimpse into the future

Despite the impressive improvements achieved by endocrine therapy and CDK4/6 inhibitors (CDK4/6i) and the forthcoming availability of alternative endocrine manipulations and targeted therapies, hormone-receptor positive/HER2 negative (HR+/HER2-) advanced breast cancer (ABC) is almost inevitably destined to become endocrine- refractory. At this time chemotherapy has been recently challenged and partly replaced by new targeted options as antibody-drug conjugated (ADCs). Trastuzumab-deruxtecan has been proven meaningfully superior to chemotherapy either in 1st and later lines after progression to CDK4/6i in HER2-low ABC and results with other ADCs as Sacituzumab Govitecan and Datopotamab-deruxtecan are promising, but the definition of cross-resistance between these drugs sharing either antibody or payload is crucial before implementing them in a useful sequence. While PARP inhibitors are the standard 2nd line in patients with gBRCA mutation, it is not still known whether patients with mutations of PALB2 or of other homologous recombinant defect (HRD)-related genes will benefit of the same treatment. On the other hand, the results obtained with immune checkpoint inhibitors (ICIs) in HR+ /HER2-ABC contrarily to the early setting are disappointing up to now, but investigations of ICIs in combination with other targeted drugs which may increase immune response and the search for better markers of activity are under way. Moreover the anticipation in upfront treatment of ADCs or PARPi in patients with features of putative endocrine resistance and/or of less sensitiviy to CDK4/6i and the choice of therapy in patients recurring during or soon after adjuvant CDK4/6i and olaparib represent further challenges for the future.

A system review of neoadjuvant immune checkpoint blockade for breast cancer

Background

The clinical application of immune checkpoint blockade (ICB)-based neoadjuvant therapy has been approved in breast cancer since 2021. However, no studies have evaluated its efficacy and safety in randomized and non-randomized settings. Additionally, there exists controversy about which specific subpopulation can benefit from this management strategy.

Methods

We searched MEDLINE and EMBASE databases for prospective clinical trials of ICB-based neoadjuvant therapy in breast cancer. Information regarding pathological complete response (pCR), event-free survival (EFS), overall survival (OS), and treatment-related adverse event (TRAE) were pooled to estimate the efficacy and safety. Hazard ratio, relative risk (RR) and their 95% confidence intervals (CIs) were calculated.

Results

Among 22 eligible trials including 6134 women with resectable breast cancer, there were 11 randomized studies with 5574 patients. Pooled analysis on pCR (RR, 1.38; 95% CI, 1.20-1.58; P<0.001), EFS (hazard ratio, 0.67; 95% CI, 0.54-0.81; P<0.001), and OS (hazard ratio, 0.56; 95% CI, 0.35-0.91; P=0.01) revealed that ICB-based neoadjuvant therapy was associated with favorable outcomes over conventional treatment. Moreover, the benefits of EFS were independent of PD-L1 expression (Pinteraction =0.57) and pCR (Pinteraction =0.37) in neoadjuvant immunotherapy. However, combining ICB with conventional neoadjuvant treatment significantly increased the risk of high-grade TRAE (RR, 1.06; 95% CI, 1.01-1.12; P=0.03), serious TRAE (RR, 1.57; 95% CI, 1.26-1.94; P<0.001), treatment discontinuation due to TRAE (RR, 1.47; 95% CI, 1.14-1.90; P=0.003), and potentially fatal adverse event (RR, 2.25; 95% CI, 0.80-6.31; P=0.12).

Conclusion

The combination of ICB with conventional neoadjuvant treatment is associated with favorable clinical outcomes and importantly, increased grade 3+ toxicities. Clinicians should meticulously monitor patients to minimize the risk of treatment discontinuation in individuals with potentially curable breast cancer.

Co-regulator activity of Mediator of DNA Damage Checkpoint 1 (MDC1) is associated with DNA repair dysfunction and PARP inhibitor sensitivity in lobular carcinoma of the breast

Invasive lobular carcinoma of the breast (ILC) is typically estrogen receptor α (ER)-positive and presents with biomarkers of anti-estrogen sensitive disease, yet patients with ILC face particularly poor long-term outcomes with increased recurrence risk, suggesting endocrine response and ER function are unique in ILC. ER is co-regulated by the DNA repair protein Mediator of DNA Damage Checkpoint 1 (MDC1) specifically in ILC cells, driving distinct ER activity. However, this novel MDC1 activity is associated with dysfunctional canonical DNA repair activity by MDC1, but without typical features of DNA repair deficiency. To understand reciprocal activities of MDC1, we profiled the MDC1 interactome and found MDC1-associated proteins in ILC cells mirror a "BRCA-like" state lacking key homologous recombination (HR) proteins, consistent with HR dysfunction but distinct from classic "BRCAness". HR dysfunction in ILC cells is supported by single-cell transcriptome and DNA repair activity analyses, with DNA repair signaling and functional data, showing dysfunctional induction and resolution of HR. In parallel, ILC tumor data are consistent with a distinct form of HR dysfunction via impaired HR resolution, lacking BRCA-like genomic scarring but showing elevated signatures of PARP inhibitor sensitivity. We demonstrate this HR dysfunction can be exploited using PARP inhibition, and found that talazoparib treatment produced a durable growth suppression both in vitro and in multiple ILC xenografts in vivo. ILC-specific ER:MDC1 activity creates a new context for ER and MDC1 function in ILC, at the cost of a DNA repair dysfunction, which may be therapeutically targetable.

The evolving landscape of genetic biomarkers for immunotherapy in primary and metastatic breast cancer

Background

Major advances have been achieved in the characterization of primary breast cancer genomic profiles. Limited information is available on the genomic profile of tumors originating from different metastatic locations in recurrent/metastatic (R/M) breast cancer, especially in Asian patients. This study aims to decipher the mutational profiles of primary and R/M breast cancer in Chinese patients using next-generation sequencing.

Methods

A total of 563 breast cancer patients were enrolled, and 590 tumor tissues and matched peripheral blood samples were collected and subjected to targeted sequencing with a panel of 1,021 cancer-related genes. The mutation spectrum, DNA damage response (DDR) genes, commonly altered signal pathways, and immunotherapy-related markers were compared between primary and R/M breast cancer. The molecular differences between our cohort and the Memorial Sloan Kettering Cancer Center (MSKCC) dataset were also explored.

Results

A total of 361 samples from primary and 229 samples from R/M breast cancer were analyzed. BRCA2, ATRX, and ATM were more frequently observed in R/M lesions among the 36 DDR genes. An ESR1 mutation and PD-L1 and PD-L2 amplification were enriched in R/M breast cancer (all p<0.05). Compared with the MSKCC dataset, we recruited more patients diagnosed at age 50 or younger and more patients with triple-negative breast cancer (TNBC) subtypes. The TNBC patients in our dataset had a higher percentage of PD-L1 amplification in metastasis tumors (p<0.05).

Conclusions

This study revealed the distinctive mutational features of primary and R/M tumors in Chinese breast cancer patients, which are different from those from Western countries. The enrichment of PD-L1 amplification in metastatic TNBC indicates the necessity to re-biopsy metastatic tumors for immunotherapy.

Natural Products as Novel Therapeutic Agents for Triple-Negative Breast Cancer: Current Evidence, Mechanisms, Challenges, and Opportunities

Breast cancer (BC) tops the list of causes for female fatalities globally, with the elusive triple-negative breast cancer (TNBC) constituting 10-20% of all cases. Current clinical strategies for combating TNBC encompass a multifaceted approach, including surgical intervention, radiation therapy, chemotherapy, and advanced targeted drugs and immunotherapies. While these modalities have catalyzed significant advancements in TNBC management, lingering limitations continue to pose formidable challenges. There is an acute need for novel therapeutics in the realm of TNBC treatment. Natural products (NPs) have emerged as a rich reservoir for pharmaceutical innovation, owing to their extraordinary range of structures and physicochemical properties. Scholars have reported diverse evidence of NPs' efficacy against TNBC. This review aims to comprehensively explore the bioactive constituents, specifics and commonalities of chemical structure, and pharmacological mechanisms of NPs, specifically examining their multifaceted roles in impeding TNBC. NPs, which have recently garnered significant interest, are intriguing in terms of their capacity to combat TNBC through multifaceted mechanisms, including the suppression of tumor cell proliferation, the induction of apoptosis, and the inhibition of tumor metastasis. These natural agents primarily encompass a range of compounds, including terpenoids, glycosides, phenolic compounds, and alkaloids. An in-depth exploration has unveiled their involvement in key signaling pathways, including the transforming growth factor-beta (TGF-β), vascular endothelial growth factor A (VEGFA), phosphoinositide 3-kinase/protein kinase B (PI3K/AKT), Wingless/Int-1 (Wnt) /β-catenin, and mitogen-activated protein kinase (MAPK) pathways. Meanwhile, this review also looks at the challenges and opportunities that arise from harnessing natural compounds to influence TNBC, while outlining the prospective trajectory for future research in the field of NPs.

Profiling Multiple CD8+ T-cell Functional Dimensions Enhances Breast Cancer Immune Assessment

CD8+ T-cell abundance is insufficient to assess antitumor immunity and shows poor performance in predicting breast cancer prognosis and immunotherapy response, presumably owing to the complexity of CD8+ T-cell functionalities. Although single-cell RNA sequencing can dissect the multifaceted functions of CD8+ T cells for better immune assessment, its clinical application is limited. In this study, we developed bulk RNA sequencing-based FuncDimen models from integrative analysis of single-cell RNA sequencing and matched bulk RNA sequencing data to evaluate CD8+ T-cell functionalities across five dimensions: tumor reactivity, cytotoxicity, IFNγ secretion, proliferation, and apoptosis. The FuncDimen models quantifying different functional dimensions of CD8+ T cells were validated in our breast cancer cohort and external databases using immunofluorescence and imaging mass cytometry. We calculated the FuncAggre score by weighted aggregation of all five FuncDimen models to encapsulate the overall antitumor immunity. In our breast cancer cohort and external databases, the FuncAggre score demonstrated superior predictive performance for breast cancer prognosis (time-dependent AUC: 0.56-0.70) and immunotherapy response (AUC: 0.71-0.83) over other immune biomarkers, regardless of the breast cancer molecular subtype. Together, the FuncDimen models offer a refined assessment of antitumor immunity mediated by CD8+ T cells in the clinic, enhancing prognostic prediction and aiding personalized immunotherapy in breast cancer.

Analysis of the chemotherapy effect of albumin-bound paclitaxel combined with pirarubicin and cyclophosphamide on breast cancer and the effects of PCR, ORR, and CBR

Objective

To explore the chemotherapy effect of albumin-bound paclitaxel combined with pirarubicin and cyclophosphamide on breast cancer and the effects of PCR, ORR and CBR.

Methods

This was a retrospective study. During the period from January 2022 to December 2023, ninety patients with breast cancer who were treated in The First People's Hospital of Changde City were included as the research objects. Based on the principle of randomized control, the above patients were divided into the control group (45 cases, treated with pirarubicin and cyclophosphamide) and the observation group (45 cases, treated with albumin-bound paclitaxel combined with pirarubicin and cyclophosphamide) by the random number table. Compared the chemotherapy effect and safety of the two groups.

Results

After treatment, the PCR, ORR and CBR of the observation group were higher than those of the control group, while the levels of CA152, CA125, TPS, HER-2, Ki-67 and EGFR were lower than those of the control group, and the differences were statistically significant (P<0.05). The incidence of adverse reactions was 33.33% (15/45), which was slightly higher than that of 28.89% (13/45) in the control group, the difference was not statistically significant (P>0.05).

Conclusion

Albumin-bound paclitaxel combined with pirarubicin and cyclophosphamide is a safe regimen that can further enhance the effect of neoadjuvant chemotherapy in the treatment of breast cancer, and it has a certain value for dissemination in the treatment of breast cancer can further enhance the effect of neoadjuvant chemotherapy in patients, which is of certain value for clinical promotion.

CD47 is a tumor cell-derived exosomal signature and regulates tumor immune microenvironment and immunotherapy responses

BACKGROUND

The pathogenesis of ovarian cancer (OvCa) involves a complex interplay of genetic, environmental, and hormonal factors. With the in-depth exploration of tumor ecosystem, exosomes can mediate the immunological status of tumor microenvironment (TME). Therefore, we aimed to recognize the tumor-derived exosomes (TEXs) which can distinguish the immune-hot and cold tumors and reflect the immunotherapeutic responses.

METHODS

A large set of transcriptomic and single-cell RNA-sequencing (scRNA-seq) datasets were downloaded and used to analyze the expression pattern of CD47 and its immuno-correlations in OvCa and multiple epithelial cell carcinomas such as breast cancers. In addition, a pan-gynecological cancer cohort was used to validate the correlation between CD47 and the inflamed TME.

RESULTS

In the current study, we found that CD47 was a TEX signature and had no transcriptional differences among patients with different clinicopathological features. Moreover, CD47 expression was positively correlated with the activation of immunological signaling pathways and enrichment of immune cell subpopulations in OvCa. Furthermore, in breast cancer and gynecological cancers, CD47, specially expressed in tumor cells, also showed favorable ability to distinguish the immune-hot and cold carcinomas. Moreover, in immunotherapy cohorts of breast cancer and other epithelial cell carcinomas, patients with CD47-high phenotype were more sensitive to immunotherapy and tended to achieve remission after treatment. Results from the TMA showed that CD47 was upregulated in tumor tissues and positively correlated with CD8 level.

CONCLUSION

In conclusion, CD47 is associated with an inflammatory TME, immune-hot tumors, and sensitivity of immunotherapy, highlighting the values of CD47 in identifying immunological traits and an immunotherapeutic response.

Extracellular matrix cancer-associated fibroblasts promote stromal fibrosis and immune exclusion in triple-negative breast cancer

The impact of high heterogeneity of cancer-associated fibroblasts (CAFs) on triple-negative breast cancer (TNBC) immunotherapy response has not been fully elucidated, restricting progress in precision immuno-oncology. We integrated single-cell transcriptomic data from 18 TNBC patients and analyzed fibroblast subpopulations. Extracellular matrix CAFs (ecmCAFs) were identified as a fibroblast subpopulation with distinct ECM-associated characteristics. The ecmCAFs were significantly enriched in TNBC patients with residual disease after neoadjuvant immunotherapy and contributed to a fibrotic tumor microenvironment and T-cell exclusion. Secreted phosphoprotein 1 (SPP1) positive macrophages (SPP1+ Mφs) were closely localized to ecmCAFs and produced more transforming growth factor beta (TGFB1), interleukin 1 beta (IL1B), and SPP1 under hypoxic conditions. SPP1+ Mφs were found to facilitate the differentiation of normal breast fibroblasts to ecmCAFs, thus promoting ECM remodeling and stromal fibrosis. Our work revealed the critical role of ecmCAFs in generating a desmoplastic architecture and driving immunosuppression in TNBC. © 2025 The Pathological Society of Great Britain and Ireland.

Breast cancer: pathogenesis and treatments

Breast cancer, characterized by unique epidemiological patterns and significant heterogeneity, remains one of the leading causes of malignancy-related deaths in women. The increasingly nuanced molecular subtypes of breast cancer have enhanced the comprehension and precision treatment of this disease. The mechanisms of tumorigenesis and progression of breast cancer have been central to scientific research, with investigations spanning various perspectives such as tumor stemness, intra-tumoral microbiota, and circadian rhythms. Technological advancements, particularly those integrated with artificial intelligence, have significantly improved the accuracy of breast cancer detection and diagnosis. The emergence of novel therapeutic concepts and drugs represents a paradigm shift towards personalized medicine. Evidence suggests that optimal diagnosis and treatment models tailored to individual patient risk and expected subtypes are crucial, supporting the era of precision oncology for breast cancer. Despite the rapid advancements in oncology and the increasing emphasis on the clinical precision treatment of breast cancer, a comprehensive update and summary of the panoramic knowledge related to this disease are needed. In this review, we provide a thorough overview of the global status of breast cancer, including its epidemiology, risk factors, pathophysiology, and molecular subtyping. Additionally, we elaborate on the latest research into mechanisms contributing to breast cancer progression, emerging treatment strategies, and long-term patient management. This review offers valuable insights into the latest advancements in Breast Cancer Research, thereby facilitating future progress in both basic research and clinical application.

VEGFA Gene Expression in Breast Cancer Is Associated With Worse Prognosis, but Better Response to Chemotherapy and Immunotherapy

Background

Vascular endothelial growth factor-A (VEGFA) is a key inducer of angiogenesis, responsible for generating new blood vessels in the tumor microenvironment (TME) and facilitating metastasis. Notably, Avastin, which targets VEGFA, failed to demonstrate any significant benefit in clinical trials for breast cancer (BC). This study aimed to investigate the clinical relevance of VEGFA gene expression in BC.

Methods

A total of 7,336 BC patients across eight independent cohorts: ISPY2 (GSE173839), Sweden Cancerome Analysis Network-Breast (SCAN-B) (GSE96058), Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), GSE25066, GSE163882, GSE34138, GSE20194, and The Cancer Genome Atlas (TCGA), were analyzed. The calculated median VEGFA expression level was used to stratify these cohorts into high and low groups.

Results

High VEGFA was associated with worse disease-free, disease-specific, and overall survival in the METABRIC cohort, with findings supported by the SCAN-B cohort, which also showed worse overall survival (all P < 0.02). High VEGFA expression was seen in triple-negative breast cancer (TNBC) but not in BC with lymph node metastasis. Additionally, there was a significant correlation between high VEGFA expression and higher silent and non-silent mutations, single-nucleotide variant (SNV) neoantigens, homologous recombination defect, intratumoral heterogeneity, in the TCGA cohort. In the TCGA, METABRIC, and SCAN-B cohorts, high VEGFA BC was also associated with higher cell proliferation: higher Ki67 gene expression, higher Nottingham histological grade, and consistent enrichment of all the Hallmark cell proliferation-related gene sets. Unexpectedly, the angiogenesis gene set was not enriched in any of the cohorts and showed no association with infiltrations of lymphatic or blood vascular endothelial cells besides pericytes. High VEGFA BC had significantly less infiltration of anti-cancer immune cells but higher infiltration of pro-cancer immune cells in TCGA, METABRIC, and SCAN-B cohorts. Interestingly, BC, which had a pathological complete response (pCR) after anthracycline- and taxane-based neoadjuvant therapy, was associated with significantly heightened VEGFA expression in both estrogen receptor (ER)+/human epidermal growth factor receptor 2 (HER2)- and TNBC subtypes in the GSE25066 cohort and after immunotherapy in ER+/ HER2- subtype, but not TNBC in the ISPY2 cohort.

Conclusions

Our research indicates that high VEGFA BC confers high cell proliferation, reduced immune cell infiltration, and poorer survival, but allows better response to anthracycline- and taxane-based chemotherapy, and immunotherapy.

Heterogeneity of tertiary lymphoid structures predicts the response to neoadjuvant therapy and immune microenvironment characteristics in triple-negative breast cancer

BACKGROUND

Tertiary lymphoid structures (TLSs) impact cancer outcomes, including in triple-negative breast cancer (TNBC), where their role in immune modulation during neoadjuvant therapy (NAT) is underexplored.

METHODS

This study employed single-cell RNA sequencing (scRNA-seq), multiplex immunofluorescence (mIF) staining, and radiomic techniques to evaluate TLSs and the tumour microenvironment (TME) in TNBC patient samples before and after NAT.

RESULTS

The presence of TLSs in TNBC was associated with B-cell maturation and T-cell activation. Compared with TLS-low TNBC, TLS-high TNBC showed significantly greater expression of immunoglobulin family genes (IGHM and IGHG1) in B cells and greater cytotoxicity of neoantigen-specific CD8 + T cells (neoTCR8). Additionally, mIF revealed notable differences between TLSs and the TME in TNBC. Although CD8 + T-cell levels do not predict the NAT response effectively, TLS maturity strongly correlated with better NAT outcomes and prognosis (P < 0.05). An imaging biomarker scoring system was also developed to predict TLS status and NAT efficacy.

CONCLUSION

Our results demonstrated changes in TLSs and the TME in TNBC patients post-NAT. These findings confirm the predictive value of mature TLSs (mTLSs) and support the use of personalised immunotherapy based on post-NAT immune characteristics, thereby improving clinical outcomes.

Graph convolution networks model identifies and quantifies gene and cancer specific transcriptome signatures of cancer driver events

BACKGROUND

The identification and drug targeting of cancer causing (driver) genetic alterations has seen immense improvement in recent years, with many new targeted therapies developed. However, identifying, prioritizing, and treating genetic alterations is insufficient for most cancer patients. Current clinical practices rely mainly on DNA level mutational analyses, which in many cases fail to identify treatable driver events. Arguably, signal strength may determine cell fate more than the mutational status that initiated it. The use of transcriptomics, a complex and highly informative representation of cellular and tumor state, had been suggested to enhance diagnostics and treatment successes. A gene-expression based model trained over known genetic alterations could improve identification and quantification of cancer related biological aberrations' signal strength.

METHODS

We present STAMP (Signatures in Transcriptome Associated with Mutated Protein), a Graph Convolution Networks (GCN) based framework for the identification of gene expression signatures related to cancer driver events. STAMP was trained to identify the p53 dysfunction of cancer samples from gene expression, utilizing comprehensive curated graph structures of gene interactions. Predictions were modified for generating a quantitative score to rank the severity of a driver event in each sample. STAMP was then extended to almost 300 tumor type-specific predictive models for important cancer genes/pathways, by training to identify well-established driver events' annotations from the literature.

RESULTS

STAMP achieved very high AUC on unseen data across several tumor types and on an independent cohort. The framework was validated on p53 related genetic and clinical characteristics, including the effect of Variants of Unknown Significance, and showed strong correlation with protein function. For genes and tumor types where targeted therapy is available, STAMP showed correlation with drugs sensitivity (IC50) in an independent cell line database. It managed to stratify drug effect on samples with similar mutational profiles. STAMP was validated for drug-response prediction in clinical patients' cohorts, improving over a state-of-the-art method and suggesting potential biomarkers for cancer treatments.

CONCLUSIONS

The STAMP models provide a learning framework that successfully identifies and quantifies driver events' signal strength, showing utility in portraying the molecular landscape of tumors based on transcriptomics. Importantly, STAMP manifested the ability to improve targeted therapy selection and hence can contribute to better treatment.

Cardiotoxicity associated with immune checkpoint inhibitors: Systematic review and meta-analysis

BACKGROUND AND AIMS

The aim of this systematic review was to assess the risk of cardiac toxicity in patients undergoing approved PD-1 (nivolumab, pembrolizumab, cemiplimab, dostarlimab), PD-L1 (atezolizumab, avelumab, durvalumab), and CTLA-4 (ipilimumab) inhibitors.

RESULTS

Among a total of 2272 articles, 11 phase II and III clinical trials included: 5463 patients and 175 cardiac adverse events. The most common cardiac disorder was atrial fibrillation (12 %), while cardiac arrest and cardiac failure (6 %) led to death in three cases. Overall, ICI treatment increased the risk of cardiotoxicity compared with control groups (RR=1.62, 95 %-CI= 1.18-2.24, p-value=0.0033; OR=1.71, 95 %-CI= 1.20-2.42, p-value=0.0027).

CONCLUSIONS

This study proved that the recognition of frequency and severity of all grade cardiotoxicity associated with ICIs is still underestimated. Thus, a systematic cardiological screening becomes necessary, in order to intercept the potential cardiological complications beforehand and optimize the outcomes of the respective treatment with PD-1, PD-L1 and CTLA-4 inhibitors.

Hormone Receptor-Positive HER2-Negative/MammaPrint High-2 Breast Cancers Closely Resemble Triple-Negative Breast Cancers

PURPOSE

The MammaPrint (MP) prognostic assay categorizes breast cancers into high- and low-risk subgroups, and the high-risk group can be further subdivided into high-1 (MP-H1), and very high-risk high-2 (MP-H2). The aim of this analysis was to assess clinical and molecular differences between the hormone receptor-positive (HR+)/HER2-negative MP-H1, -H2, and triple-negative (TN) MP-H1 and -H2 cancers.

EXPERIMENTAL DESIGN

Pretreatment gene expression data from 742 HER2-negative breast cancers enrolled in the I-SPY2 neoadjuvant trial were used. Prognostic risk categories were assigned using the MP assay. Transcriptional similarities across the four receptor and prognostic groups were assessed using principal component analyses and by identifying differentially expressed genes. We also examined pathologic complete response rates and event-free survivals by risk group.

RESULTS

Principal component analysis showed that HR+/MP-H2 tumors clustered with TN/MP-H2 cancers. Only 125 genes showed differential expression between the HR+/MP-H2 and TN/MP-H2 cancers, whereas 1,465 genes were differentially expressed between HR+/MP-H2 and -H1. Gene set analysis revealed similarly high expression of cell cycle, DNA repair, and immune infiltration-related pathways in HR+/MP-H2 and TN/MP-H2 cancers. HR+/MP-H2 cancers also showed low estrogen receptor-related gene expression. Pathologic complete response rates were similarly high in TN/MP-H2 and HR+/MP-H2 cancers (42% vs. 30.5%; P = 0.11), and MP-H2 cancers with residual cancer had similarly poor event-free survival regardless of estrogen receptor status.

CONCLUSIONS

In conclusion, HR+/MP-H2 cancers closely resemble TN breast cancers in transcriptional and clinical features and benefit from similar treatment strategies.

TBX3 shapes an immunosuppressive microenvironment and induces immunotherapy resistance

Background: Identifying biomarkers that predict immunotherapy efficacy and discovering new targets for combination therapies are critical elements for improving the prognosis of bladder cancer (BLCA) patients. Methods: Firstly, we explored the expression patterns of TBX3 in normal and pan-cancer tissues and the correlation between TBX3 and the immune microenvironment using data from multiple public databases. Then, we combined various techniques, including bulk RNA sequencing, single-cell RNA sequencing, high-throughput cytokine arrays, functional experiments, ProcartaPlex multiplex immunoassays and TissueFAXS panoramic tissue quantification assays, to demonstrate that TBX3 shapes an immunosuppressive tumor microenvironment (TME) in BLCA. Results: We identified TBX3 as a key factor associated with the immunosuppressive microenvironment in BLCA through a systematic multi-omics analysis. We found that TBX3 is primarily expressed in malignant cells, where TBX3high tumor cells increase the secretion of TGFβ1, which promotes the infiltration of cancer-associated fibroblasts (CAFs), thereby forming an immunosuppressive microenvironment. We further demonstrated that TBX3 enhances TGFβ1 expression by binding to the TGFβ1 promoter, and blocking TGFβ1 counteracts the immunosuppressive effects of TBX3. Moreover, TBX3 reduced the cancer-killing efficiency of CD8+ T cells by decreasing the proportion of GZMB+ CD8+ T cells, and knocking down TBX3 combined with anti-PD-1 treatment increased CD8+ T cell infiltration and reduced CAFs in vivo. We also validated the inverse relationship between TBX3+ malignant cells and CD8+ T cells and the positive relationship with CAFs in tissue microarrays. Lastly, we found that TBX3 predicted immunotherapy efficacy in our real-world immunotherapy cohort and multiple public cohorts. Conclusion: In summary, TBX3 promotes BLCA progression and immunotherapy resistance by inducing an immunosuppressive microenvironment, and targeting TBX3 could enhance the efficacy of immunotherapy for BLCA.

Comprehensive Pan-cancer Analysis of CMPK2 as Biomarker and Prognostic Indicator for Immunotherapy

BACKGROUND

UMP-CMP kinase 2 (CMPK2) is involved in mitochondrial DNA synthesis, which can be oxidized and released into the cytoplasm in innate immunity. It initiates the assembly of NLRP3 inflammasomes and mediates various pathological processes such as human immunodeficiency virus infection and systemic lupus erythematosus. However, the role of CMPK2 in tumor progression and tumor immunity remains unclear.

METHODS

We identified CMPK2 expression patterns in the Genotype Tissue-Expression (GTEx), The Cancer Genome Atlas (TCGA), and the Cancer Cell Line Encyclopedia (CCLE) databases. Validation was performed using immunohistochemical staining data from the Human Protein Atlas (HPA) database and qPCR experiments. Receiver operating characteristic curve analysis and Kaplan-Meier survival analysis were conducted to assess the clinical relevance of CMPK2 expression. The Estimation of Stromal and Immune Cells in Malignant Tumor Tissues Using Expression Data (ESTIMATE) algorithm and the Tumor IMmune Estimation Resource (TIMER) database were used to evaluate the correlation between CMPK2 and immune infiltration in tumors. The Tumor Immune Syngeneic Mouse (TISMO) database and other public datasets were utilized to assess the impact of CMPK2 on immune therapy response. MEXPRESS and MethSurv databases were employed to investigate the effects of methylation on CMPK2 expression.

RESULTS

CMPK2 expression was elevated in 23 cancers and decreased in two cancers. Furthermore, CMPK2 expression had a high diagnostic value for 16 cancers. Elevated CMPK2 expression was associated with lower overall survival (OS), disease-specific survival (DSS), and progression- free interval (PFI) in four cancers. Immune microenvironment-related analysis revealed strong associations between CMPK2 expression and immune cell infiltration, as well as immune checkpoint expression across various tumors. Notably, in four mouse immunotherapy cohorts, CMPK2 expression in treated mouse tumors was higher post-treatment. In five clinical immunotherapy cohorts, patients with high CMPK2 expression show better responses to immunotherapy. Moreover, the methylation level of CMPK2 gene was closely correlated to its expression and tumor prognosis. Among these cancers, the clinical and immunological indications of skin cutaneous melanoma (SKCM) are particularly closely related to CMPK2 expression.

CONCLUSION

Our analysis preliminarily describes the complex function of CMPK2 in cancer progression and immune microenvironment, highlighting its potential as a diagnostic and therapeutic target for immunotherapy.

Estrogen Signaling in Early-Stage Breast Cancer: Impact on Neoadjuvant Chemotherapy and Immunotherapy

Neoadjuvant chemoimmunotherapy (NACIT) has been shown to improve pathologic complete response (pCR) rates and survival outcomes in stage II-III triple-negative breast cancer (TNBC). Promising pCR rate improvements have also been documented for selected patients with estrogen receptor-positive (ER+) human epidermal growth factor receptor 2-negative (HER2-) breast cancer (BC). However, one size does not fit all and predicting which patients will benefit from NACIT remains challenging. Accurate predictions would be useful to minimize immune-related toxicity, which can be severe, irreversible, and potentially impact fertility and quality of life, and to identify patients in need of alternative treatments. This review aims to capitalize on the existing translational and clinical evidence on predictors of treatment response in patients with early-stage BC treated with neoadjuvant chemotherapy (NACT) and NACIT. It summarizes evidence suggesting that NACT/NACIT effectiveness may correlate with pre-treatment tumor characteristics, including mutational profiles, ER expression and signaling, immune cell presence and spatial organization, specific gene signatures, and the levels of proliferating versus quiescent cancer cells. However, the predominantly qualitative and descriptive nature of many studies highlights the challenges in integrating various potential response determinants into a validated, comprehensive, and multimodal predictive model. The potential of novel multi-modal approaches, such as those based on artificial intelligence, to overcome current challenges remains unclear, as these tools are not free from bias and shortcut learning. Despite these limitations, the rapid evolution of these technologies, coupled with further efforts in basic and translational research, holds promise for improving treatment outcome predictions in early HER2- BC.

Olaparib-associated toxicity in cancer patients: a systematic review and meta-analysis

PURPOSE

To investigate the characteristics of olaparib-associated adverse events (AEs) in cancer patients.

METHODS

Databases were searched for phase II and III randomized controlled trials (RCTs) involving olaparib treatment up to March 2024. A systematic assessment was performed.

RESULTS

Twenty-seven RCTs involving 9542 patients were included. This meta-analysis indicates that olaparib could significantly increase the risk of developing any all-grade (RR, 1.08; 95% CI, 1.03-1.13; p = 0.001) and high-grade (RR, 1.45; 95% CI, 1.19-1.77; p = 0.0003) AEs in cancer patients. Olaparib could increase the risk of dose reduction (RR, 3.00; 95% CI, 1.59-5.70; p = 0.0007) and treatment discontinuation (RR, 2.00; 95% CI, 1.28-3.14; p = 0.002). Hematologic toxicities and gastrointestinal toxicities commonly occur in patients receiving olaparib. Anemia, nausea, and fatigue were the most frequent AEs, with olaparib increasing the risk of both all-grade and high-grade occurrences of these events. Patients with longer treatment durations tend to have a higher risk of anemia. Patients with urinary system tumors tend to have a higher risk of nausea, while those with breast cancer tend to have a higher risk of fatigue. Olaparib maintenance therapy may be associated with a higher risk of fatigue. Olaparib could increase other AEs such as diarrhea, vomiting, decreased appetite, dyspepsia, dysgeusia, dizziness, headache, back pain, urinary tract infection, dyspnea, and cough.

CONCLUSION

Olaparib-containing therapy could increase the occurrence of specific AEs in patients with cancer. Clinicians should be aware of these risks and conduct regular monitoring.

Clinical Implications of Breast Cancer Intrinsic Subtypes

Estrogen receptor-positive (ER+) and estrogen receptor-negative (ER-) breast cancers have different genomic architecture and show large-scale gene expression differences consistent with different cellular origins, which is reflected in the luminal (i.e., ER+) versus basal-like (i.e., ER-) molecular class nomenclature. These two major molecular subtypes have distinct epidemiological risk factors and different clinical behaviors. Luminal cancers can be subdivided further based on proliferative activity and ER signaling. Those with a high expression of proliferation-related genes and a low expression of ER-associated genes, called luminal B, have a high risk of early recurrence (i.e., within 5 years), derive significant benefit from adjuvant chemotherapy, and may benefit from adding immunotherapy to chemotherapy. This subset of luminal cancers is identified as the genomic high-risk ER+ cancers by the MammaPrint, Oncotype DX Recurrence Score, EndoPredict, Prosigna, and several other molecular prognostic assays. Luminal A cancers are characterized by low proliferation and high ER-related gene expression. They tend to have excellent prognosis with adjuvant endocrine therapy. Adjuvant chemotherapy may not improve their outcome further. These cancers correspond to the genomic low-risk categories. However, these cancers remain at risk for distant recurrence for extended periods of time, and over 50% of distant recurrences occur after 5 years. Basal-like cancers are uniformly highly proliferative and tend to recur within 3-5 years of diagnosis. In the absence of therapy, basal-like breast cancers have the worst survival, but these also include many highly chemotherapy-sensitive cancers. Basal-like cancers are often treated with preoperative chemotherapy combined with an immune checkpoint inhibitor which results in 60-65% pathologic complete response rates that herald excellent long-term survival. Patients with residual cancer after neoadjuvant therapy can receive additional postoperative chemotherapy that improves their survival. Currently, there is no clinically actionable molecular subclassification for basal-like cancers, although cancers with high androgen receptor (AR)-related gene expression and those with high levels of immune infiltration have better prognosis, but currently their treatment is not different from basal-like cancers in general. A clinically important, minor subset of breast cancers are characterized by frequent HER2 gene amplification and high expression of a few dozen genes, many residing on the HER2 amplicon. This is an important subset because of the highly effective HER2 targeted therapies which are synergistic with endocrine therapy and chemotherapy. The clinical behavior of HER2-enriched cancers is dominated by the underlying ER subtype. ER+/HER2-enriched cancers tend to have more indolent course and lesser chemotherapy sensitivity than their ER counterparts.

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.

Efficacy and Safety of Paclitaxel-Based PD-1/PD-L1 Immunotherapies for Triple-Negative Breast Cancer: A Systematic Review and Network Meta-Analysis

Background

Triple negative breast cancer (TNBC) is a deadly subtype of breast cancer with limited treatment options. Currently, programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) inhibitors have become the first choice for breast cancer immunotherapies. Despite paclitaxel being considered a cornerstone drug in breast cancer treatment, the effectiveness, safety, and optimal drug selection for its combination with PD-1/PD-L1 inhibitors remain uncertain.

Methods

We conducted a systematic review and network meta-analysis, performing a comprehensive literature search across PubMed, Embase, and the Cochrane Library from the inception of each database through May 18, 2024. Selected trials were those that assessed the efficacy and safety of paclitaxel-based PD-1/PD-L1 therapies for the treatment of TNBC. The primary endpoint assessed was overall survival (OS), while secondary outcomes included progression-free survival (PFS), adverse events (AEs), overall response rate (ORR), and Pathological complete response (pCR). This study is registered in PROSPERO under registration number CRD42023429651.

Results

A total of 8 RCTs meeting our eligibility criteria were included, involving 4626 patients who received either Paclitaxel (Paclitaxel-placebo/chemotherapy) or a combination of durvalumab, pembrolizumab, atezolizumab, toripalimab with paclitaxel. The pooled results demonstrated that Durvalumab combined with Paclitaxel significantly reduced the hazard ratio for OS (surface under the cumulative ranking [SUCRA]: 91.05%) and PFS compared with Paclitaxel alone (SUCRA: 83.52%). Additionally, Durvalumab plus Paclitaxel significantly improved the ORR compared with Paclitaxel (odds ratio [OR]: 2.30; 95% credible interval [CrI]: 1.10-5.20). For safety outcomes, Atezolizumab plus Paclitaxel showed a favorable profile in AEs, with no significant differences observed between groups. In the pCR study, Pembrolizumab plus Paclitaxel was the most effective treatment option (SUCRA: 81.85%).

Conclusions

When combined with paclitaxel, PD-1/PD-L1 inhibitors exhibit a favorable survival benefit. The combination of Durvalumab and paclitaxel represents the optimal treatment option. In the future, attention should be paid to the TNBC subtypes and drug dosage, as these factors may help to design personalized TNBC treatment programs.

PEARL: A Phase Ib/II Biomarker Study of Adding Radiation Therapy to Pembrolizumab Before Neoadjuvant Chemotherapy in Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer

PURPOSE

To assess safety and immune biomarkers after preoperative radiation therapy (RT) and anti-PD1 therapy in breast cancer.

MATERIALS AND METHODS

A phase I/IIb trial of pembrolizumab with RT was conducted in patients with triple-negative breast cancer (TNBC) and hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) breast cancer. All received pembrolizumab followed by a second cycle + RT (anti-PD1/RT) of 24 Gy/three daily fractions delivered to the breast tumor and then neoadjuvant chemotherapy (NAC). Blood and tumor biopsies were obtained at baseline, after anti-PD1, and after anti-PD-RT. Coprimary end points were safety and change in tumor-infiltrating lymphocytes (TILs). Secondary end points were pathologic complete response (pCR), residual cancer burden (RCB) rates, and event-free survival (EFS).

RESULTS

Sixty-six patients with stage I-III breast cancer (54 TNBC, 12 HR+/HER2-) were enrolled. The median follow-up was 32 months. Safety end point was met. Incidence of grade ≥3 toxicities was 41%. The pCR rate was 59.2%, 33.3%, and 54.5% for the TNBC, HR+/HER2-, and entire cohort, respectively. A total of 77.8% of TNBC and 41.6% of HR+/HER2- had a near pCR (RCB 0-1). The 3-year EFS was 80%. In the entire cohort, PD-L1 expression increased after anti-PD1 (median Combined Positive Score [CPS], 7.49-23.20; 95% CI, -41.88 to -6.30; P = .044) and anti-PD1/RT (median CPS, 7.49-23.41; 95% CI, -41.88 to -6.30; P = .009), compared with baseline. In TNBC, adding RT to anti-PD1 significantly decreased TILs (28.9%-17.1%; 95% CI, 2.46 to 21.09; P = .014). Baseline TILs correlated with PD-L1 expression and TNF-a.

CONCLUSION

Preoperative RT with pembrolizumab is safe and results in high pCR rates and 3-year EFS, despite the lack of pembrolizumab during NAC. PD-L1 and TILs may be predictive biomarkers for preoperative anti-PD1/RT response. Reduction in TILs after adding RT to anti-PD1 highlights the importance of treatment sequencing.

Immunotherapy for hormone receptor‒positive HER2-negative breast cancer

Additional therapies are needed to improve outcomes in patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative breast cancer. Research on the potential role of immunotherapy, particularly programmed cell death protein 1/programmed cell death ligand 1 inhibitors, is rapidly expanding in both the early and metastatic settings with some preliminary evidence suggesting benefit when used as part of combination therapy. Several ongoing phase 3 studies should help define their future role in treating these patients.

Immune and gene-expression profiling in estrogen receptor low and negative early breast cancer

BACKGROUND

The cutoff of <1% positive cells to define estrogen receptor (ER) negativity by immunohistochemistry (IHC) in breast cancer (BC) is debated. We explored the tumor immune microenvironment and gene-expression profile of patients with early-stage HER2-negative ER-low (ER 1%-9%) BC, comparing them to ER-negative (ER <1%) and ER-intermediate (ER 10%-50%) tumors.

METHODS

Among 921 patients with early-stage I-III, ER ≤50%, HER2-negative BCs, tumors were classified as ER-negative (n = 712), ER-low (n = 128), or ER-intermediate (n = 81). Tumor-infiltrating lymphocytes (TILs) were evaluated. CD8+, FOXP3+ cells, and PD-L1 status were assessed by IHC and quantified by digital pathology. We analyzed 776 BC-related genes in 116 samples. All tests were 2-sided at a <.05 significance level.

RESULTS

ER-low and ER-negative tumors exhibited similar median TILs, statistically significantly higher than ER-intermediate tumors. CD8/FOXP3 ratio and PD-L1 positivity rates were comparable between ER-low and ER-negative groups. These groups showed similar enrichment in basal-like intrinsic subtypes and comparable expression of immune-related genes. ER-low and ER-intermediate tumors showed significant transcriptomic differences. High TILs (≥30%) were associated with improved relapse-free survival (RFS) in ER-low (5-year RFS 78.6% vs 66.2%, log-rank P = .033, hazard ratio [HR] 0.37 [95% CI = 0.15 to 0.96]) and ER-negative patients (5-year RFS 85.2% vs 69.8%, log-rank P < .001, HR 0.41 [95% CI = 0.27 to 0.60]).

CONCLUSIONS

ER-low and ER-negative tumors are similar biological and molecular entities, supporting their comparable clinical outcomes and treatment responses, including to immunotherapy. Our findings contribute to the growing evidence calling for a reevaluation of ER-positive BC classification and management, aligning ER-low and ER-negative tumors more closely.

Datopotamab-deruxtecan plus durvalumab in early-stage breast cancer: the sequential multiple assignment randomized I-SPY2.2 phase 2 trial

Sequential adaptive trial designs can help accomplish the goals of personalized medicine, optimizing outcomes and avoiding unnecessary toxicity. Here we describe the results of incorporating a promising antibody-drug conjugate, datopotamab-deruxtecan (Dato-DXd) in combination with programmed cell death-ligand 1 inhibitor, durvalumab, as the first sequence of therapy in the I-SPY2.2 phase 2 neoadjuvant sequential multiple assignment randomization trial for high-risk stage 2/3 breast cancer. The trial includes three blocks of treatment, with initial randomization to different experimental agent(s) (block A), followed by a taxane-based regimen tailored to tumor subtype (block B), followed by doxorubicin-cyclophosphamide (block C). Subtype-specific algorithms based on magnetic resonance imaging volume change and core biopsy guide treatment redirection after each block, including the option of early surgical resection in patients predicted to have a high likelihood of pathologic complete response, which is the primary endpoint assessed when resection occurs. There are two primary efficacy analyses: after block A and across all blocks for six prespecified HER2-negative subtypes (defined by hormone receptor status and/or response-predictive subtypes). In total, 106 patients were treated with Dato-DXd/durvalumab in block A. In the immune-positive subtype, Dato-DXd/durvalumab exceeded the prespecified threshold for success (graduated) after block A; and across all blocks, pathologic complete response rates were equivalent to the rate expected for the standard of care (79%), but 54% achieved that result after Dato-DXd/durvalumab alone (block A) and 92% without doxorubicin-cyclophosphamide (after blocks A + B). The treatment strategy across all blocks graduated in the hormone-negative/immune-negative subtype. No new toxicities were observed. Stomatitis was the most common side effect in block A. No patients receiving block A treatment alone had adrenal insufficiency. Dato-DXd/durvalumab is a promising therapy combination that can eliminate standard chemotherapy in many patients, particularly the immune-positive subtype.ClinicalTrials.gov registration: NCT01042379 .

Comprehensive pancancer analysis reveals that LPCAT1 is a novel predictive biomarker for prognosis and immunotherapy response

Lysophosphatidylcholine acyltransferase 1 (LPCAT1) is a crucial enzyme involved in phospholipid metabolism and is essential for maintaining the structure and functionality of biofilms. However, a comprehensive examination of the role of LPCAT1 across various cancer types is lacking. Multiple public databases have been utilized to examine LPCAT1 expression, genetic alterations, methylation, prognosis, biological function, and its relationship with antitumor immunity in different cancer types. The function of LPCAT1 in glioma, breast cancer and liver cancer cells was further verified using in vitro experiments. Our research indicated that LPCAT1 is upregulated in various cancers and is accompanied by a wide range of amplification mutations. Higher LPCAT1 expression was associated with poorer prognosis across multiple cancers. Further in vitro experiments demonstrated that interfering with LPCAT1 expression increased apoptosis in glioma, breast cancer and liver cancer cells and concurrently suppressed their proliferation and migration. Functional enrichment analysis revealed that LPCAT1-associated genes were primarily enriched in immune and cancer progression pathways, such as the JAK/STAT, MYC, and EMT, etc. Moreover, LPCAT1 expression was closely associated with immune cell infiltration and immune checkpoint-related gene expression. Interestingly, LPCAT1 expression levels were generally higher in patients in the immunotherapy response group. The combination of LPCAT1 and PDL1 serves as an effective predictor of immunotherapy response. In conclusion, LPCAT1 is involved in immune regulation and tumor progression and holds promise as a biomarker for predicting patient outcomes and immunotherapy efficacy.

Datopotamab-deruxtecan in early-stage breast cancer: the sequential multiple assignment randomized I-SPY2.2 phase 2 trial

Among the goals of patient-centric care are the advancement of effective personalized treatment, while minimizing toxicity. The phase 2 I-SPY2.2 trial uses a neoadjuvant sequential therapy approach in breast cancer to further these goals, testing promising new agents while optimizing individual outcomes. Here we tested datopotamab-deruxtecan (Dato-DXd) in the I-SPY2.2 trial for patients with high-risk stage 2/3 breast cancer. I-SPY2.2 uses a sequential multiple assignment randomization trial design that includes three sequential blocks of biologically targeted neoadjuvant treatment: the experimental agent(s) (block A), a taxane-based regimen tailored to the tumor subtype (block B) and doxorubicin-cyclophosphamide (block C). Patients are randomized into arms consisting of different investigational block A treatments. Algorithms based on magnetic resonance imaging and core biopsy guide treatment redirection after each block, including the option of early surgical resection in patients predicted to have a high likelihood of pathological complete response, the primary endpoint. There are two primary efficacy analyses: after block A and across all blocks for the six prespecified breast cancer subtypes (defined by clinical hormone receptor/human epidermal growth factor receptor 2 (HER2) status and/or the response-predictive subtypes). We report results of 103 patients treated with Dato-DXd. While Dato-DXd did not meet the prespecified threshold for success (graduation) after block A in any subtype, the treatment strategy across all blocks graduated in the hormone receptor-negative HER2-Immune-DNA repair deficiency- subtype with an estimated pathological complete response rate of 41%. No new toxicities were observed, with stomatitis and ocular events occurring at low grades. Dato-DXd was particularly active in the hormone receptor-negative/HER2-Immune-DNA repair deficiency- signature, warranting further investigation, and was safe in other subtypes in patients who followed the treatment strategy. ClinicalTrials.gov registration: NCT01042379 .

MAP3K1 mutations confer tumor immune heterogeneity in hormone receptor-positive HER2-negative breast cancer

Treatment for hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) breast cancer, the most common type of breast cancer, has faced challenges such as endocrine therapy resistance and distant relapse. Immunotherapy has shown progress in treating triple-negative breast cancer, but immunological research on HR+/HER2- breast cancer is still in its early stages. Here, we performed a multi-omics analysis of a large cohort of patients with HR+/HER2- breast cancer (n = 351) and revealed that HR+/HER2- breast cancer possessed a highly heterogeneous tumor immune microenvironment. Notably, the immunological heterogeneity of HR+/HER2- breast cancer was related to mitogen-activated protein kinase kinase kinase 1 (MAP3K1) mutation and we validated experimentally that a MAP3K1 mutation could attenuate CD8+ T cell-mediated antitumor immunity. Mechanistically, MAP3K1 mutation suppressed MHC-I-mediated tumor antigen presentation through promoting the degradation of antigen peptide transporter 1/2 (TAP1/2) mRNA, thereby driving tumor immune escape. In preclinical models, the postbiotic tyramine could reverse the MAP3K1 mutation-induced MHC-I reduction, thereby augmenting the efficacy of immunotherapy. Collectively, our study identified the vital biomarker driving the immunological heterogeneity of HR+/HER2- breast cancer and elucidated the underlying molecular mechanisms, which provided the promise of tyramine as what we believe to be a novel therapeutic strategy to enhance the efficacy of immunotherapy.

Strategies for the treatment of hormone receptor-positive HER2-low breast cancer based on clinical practice: a round table discussion

Human epidermal growth factor receptor 2 (HER2)-low breast cancer is a newly identified targetable subset of breast tumors, and its clinical characteristics and treatment strategies are controversial. The emergence of novel anti-HER2 antibody-drug conjugate (ADC) has brought promising approaches for HER2-low breast cancer treatment. Several clinical trials have validated the efficacy and safety of trastuzumab deruxtecan (T-Dxd) in HER2-low breast cancer at different treatment settings. The treatment timing, candidate identification, long-term management, and overcoming drug resistance are crucial questions to improve breast cancer patient survival. Here we present a clinical case of hormone receptor-positive (HR+) HER2-low breast cancer patient who experienced neoadjuvant chemotherapy, surgery, adjuvant, and first-line endocrine therapy with limited effectiveness. After the treatment failure of CDK4/6 inhibitors, the utilization of T-Dxd brought a long-term disease response and tolerable low toxicities. In this round table discussion, we summarized opinions and recommendations from breast cancer surgeons and oncologists on treatment strategies for this patient. The discussion mainly focused on the precise diagnosis of HER2-low breast cancer, treatment design at different disease status, regimens selection according to drug response, strategies consideration for overcoming drug resistance and the management of adverse events in long-term survival. These opinions would provide critical insights to improve HER2-low breast cancer treatment and offer valuable suggestions for clinical practice.

Comprehensive single-cell and bulk transcriptomic analyses to develop an NK cell-derived gene signature for prognostic assessment and precision medicine in breast cancer

Background

Natural killer (NK) cells play crucial roles in mediating anti-cancer activity in breast cancer (BRCA). However, the potential of NK cell-related molecules in predicting BRCA outcomes and guiding personalized therapy remains largely unexplored. This study focused on developing a prognostic and therapeutic prediction model for BRCA by incorporating NK cell-related genes.

Methods

The data analyzed primarily originated from the TCGA and GEO databases. The prognostic role of NK cells was evaluated, and marker genes of NK cells were identified via single-cell analysis. Module genes closely associated with immunotherapy resistance were identified by bulk transcriptome-based weighted correlation network analysis (WGCNA). Following taking intersection and LASSO regression, NK-related genes (NKRGs) relevant to BRCA prognosis were screened, and the NK-related prognostic signature was subsequently constructed. Analyses were further expanded to clinicopathological relevance, GSEA, tumor microenvironment (TME) analysis, immune function, immunotherapy responsiveness, and chemotherapeutics. Key NKRGs were screened by machine learning and validated by spatial transcriptomics (ST) and immunohistochemistry (IHC).

Results

Tumor-infiltrating NK cells are a favorable prognostic factor in BRCA. By combining scRNA-seq and bulk transcriptomic analyses, we identified 7 NK-related prognostic NKRGs (CCL5, EFHD2, KLRB1, C1S, SOCS3, IRF1, and CCND2) and developed an NK-related risk scoring (NKRS) system. The prognostic reliability of NKRS was verified through survival and clinical relevance analyses across multiple cohorts. NKRS also demonstrated robust predictive power in various aspects, including TME landscape, immune functions, immunotherapy responses, and chemotherapeutic sensitivity. Additionally, KLRB1 and CCND2 emerged as key prognostic NKRGs identified through machine learning and external validation, with their expression correlation with NK cells confirmed in BRCA specimens by ST and IHC.

Conclusions

We developed a novel NK-related gene signature that has proven valuable for evaluating prognosis and treatment response in BRCA, expecting to advance precision medicine of BRCA.

The Influence of Microbiota on Breast Cancer: A Review

Breast cancer remains one of the leading causes of death among women worldwide, and recent research highlights its growing connection to alterations in the microbiota. This review delves into the intricate relationship between microbiotas and breast cancer, exploring its presence in healthy breast tissue, its changes during cancer progression, and its considerable impact on both the tumor microenvironment (TME) and the tumor immune microenvironment (TIME). We extensively analyze how the microbiota influences cancer growth, invasion, metastasis, resistance to drugs, and the evasion of the immune system, with a special focus on its effects on the TIME. Furthermore, we investigate distinct microbial profiles associated with the four primary molecular subtypes of breast cancer, examining how the microbiota in tumor tissues compares with that in adjacent normal tissues. Emerging studies suggest that microbiotas could serve as valuable diagnostic and prognostic biomarkers, as well as targets for therapy. This review emphasizes the urgent need for further research to improve strategies for breast cancer prevention, diagnosis, and treatment. By offering a detailed examination of the microbiota's critical role in breast cancer, this review aims to foster the development of novel microbiota-based approaches for managing the disease.

Improving efficacy of TNBC immunotherapy: based on analysis and subtyping of immune microenvironment

Triple-negative breast cancer (TNBC) is a highly aggressive type of breast cancer that encompasses several distinct subtypes. Recent advances in immunotherapy offer a promising future for the treatment of these highly heterogeneous and readily metastatic tumors. Despite advancements, the efficacy of immunotherapy remains limited as shown by unimproved efficacy of PD-L1 biomarker and limited patient benefit. To enhance the effectiveness of TNBC immunotherapy, we conducted investigation on the microenvironment, and corresponding therapeutic interventions of TNBC and recommended further investigation into the identification of additional biomarkers that can facilitate the subtyping of TNBC for more targeted therapeutic approaches. TNBC is a highly aggressive subtype with dismal long-term survival due to the lack of opportunities for traditional endocrine and targeted therapies. Recent advances in immunotherapy have shown promise, but response rates can be limited due to the heterogeneous tumor microenvironments and developed therapy resistance, especially in metastatic cases. In this review, we will investigate the tumor microenvironment of TNBC and corresponding therapeutic interventions. We will summarize current subtyping strategies and available biomarkers for TNBC immunotherapy, with a particular emphasis on the need for further research to identify additional prognostic markers and refine tailored therapies for specific TNBC subtypes. These efforts aim to improve treatment sensitivity and ultimately enhance survival outcomes for advanced-stage TNBC patients.