Targeting HER2-positive breast cancer: advances and future directions

Role of liposomes in chemoimmunotherapy of breast cancer

In the dynamic arena of cancer therapeutics, chemoimmunotherapy has shown tremendous promise, especially for aggressive forms of breast cancer like triple-negative breast cancer (TNBC). This review delves into the significant role of liposomes in enhancing the effectiveness of chemoimmunotherapy by leveraging breast cancer-specific mechanisms such as the induction of immunogenic cell death (ICD), reprogramming the tumour microenvironment (TME), and enabling sequential drug release. We examine innovative dual-targeting liposomes that capitalise on tumour heterogeneity, as well as pH-sensitive formulations that offer improved control over drug delivery. Unlike prior analyses, this review directly links advancements in preclinical research-such as PAMAM dendrimer-based nanoplatforms and RGD-decorated liposomes-to clinical trial results, highlighting their potential to revolutionise TNBC treatment strategies. Additionally, we address ongoing challenges related to scalability, toxicity, and regulatory compliance, and propose future directions for personalised, immune-focused nanomedicine. This work not only synthesises the latest research but also offers a framework for translating liposomal chemoimmunotherapy from laboratory research to clinical practice.

Growth inhibitory peptides: a potential novel therapeutic approach to cancer treatment

Cancer remains a major global public health concern, with considerable interest in exploring biological molecules for cancer treatment and prevention. Growth inhibitory peptide (GIP), a promising new class of biological therapeutics, has drawn attention for its distinct anti-tumor properties. Derived from human alpha-fetoprotein (HAFP), this synthetic 34-amino-acid peptide has demonstrated substantial anti-tumor effects across various cancer cell lines, effectively inhibiting tumor cell proliferation, migration, and metastasis. Studies reveal that GIP mediates its effects through a range of mechanisms, including interactions with G protein-coupled receptors (GPCRs), anti-cell adhesion activities, inhibition of cell spreading and metastatic processes, morphological alterations, platelet aggregation inhibition, immune enhancement, cell membrane disruption, ion channel blockade, and cell cycle arrest. While GIP has exhibited promising anti-tumor activity in both in vitro and in vivo models, further investigation is essential to advance its development as a therapeutic drug, particularly regarding pharmacokinetics, safety profiles, storage stability, and clinical efficacy.

Targeting "don't eat me" signal: breast cancer immunotherapy

PURPOSE

Breast cancer ranks as the most prevalent cancer type impacting women globally, both in terms of incidence and mortality rates, making it a major health concern for females. There's an urgent requirement to delve into new cancer treatment methods to improve patient survival rates.

METHODS

Immunotherapy has gained recognition as a promising area of research in the treatment of breast cancer, with targeted immune checkpoint therapies demonstrating the potential to yield sustained clinical responses and improve overall survival rates. Presently, the predominant immune checkpoints identified on breast cancer cells include CD47, CD24, PD-L1, MHC-I, and STC-1, among others. Nevertheless, the specific roles of these various immune checkpoints in breast carcinogenesis, metastasis, and immune evasion have yet to be comprehensively elucidated. We conducted a comprehensive review of the existing literature pertaining to breast cancer and immune checkpoint inhibitors, providing a summary of findings and an outlook on future research directions.

RESULTS

This article reviews the advancements in research concerning each immune checkpoint in breast cancer and their contributions to immune evasion, while also synthesizing immunotherapy strategies informed by these mechanisms. Furthermore, it anticipates future research priorities, thereby providing a theoretical foundation to guide immunotherapy as a potential interventional approach for breast cancer treatment.

CONCLUSION

Knowledge of immune checkpoints will drive the creation of novel cancer therapies, and future breast cancer research will increasingly emphasize personalized treatments tailored to patients' specific tumor characteristics.

A new strategy to HER2-specific antibody discovery through artificial intelligence-powered phage display screening based on the Trastuzumab framework

Human epidermal growth factor receptor 2 (HER2) is a recognized drug target, and it serves as a critical target for various cancer treatments, necessitating the discovery of more antibodies for therapeutic and detection purposes. Here, we have developed an innovative workflow for antibody generation through Artificial Intelligence-powered Phage Display Screening (AIPDS). This workflow integrates artificial intelligence-driven antibody CDRH3 sequence design, high-throughput DNA synthesis and phage display screening. We applied AIPDS workflow to generate promising antibodies against the human epidermal growth factor receptor 2 (HER2), offering a template for streamlined antibody generation. Seven novel antibodies stood out, demonstrating promising efficacy in various functional assays. Notably, DYHER2-02 demonstrates strong performance across all experimental tests. In summary, our study introduces a novel methodology to generate new antibody variants of an existing antibody using an AI-assisted phage display approach. These new antibody variants hold potential applications in research, diagnosis, and therapeutic applications.

Clinical applications of circulating tumor cell detection: challenges and strategies

Circulating tumor cells (CTCs) are pivotal in the distant metastasis of tumors, serving as one of the primary materials for liquid biopsy. They hold significant clinical importance in assessing prognosis, predicting efficacy, evaluating therapeutic outcomes, and studying recurrence, metastasis, and resistance mechanisms in cancer patients. Nevertheless, the rareness and heterogeneity of CTC and the complexity of metastasis make the clinical application of CTC detection confront many challenges, which may need to be settled by some practical strategies. This article will review the content mentioned above.

Biologics for novel driver altered non-small cell lung cancer: potential and pitfalls

Precision medicine has revolutionized clinical paradigm of lung cancer (LC) patients optimizing therapeutical options on the basis of molecular fingerprinting of tumor cells. The advent of the genomic era contributed to the widespread diffusion of sequencing technologies laying the basis for the approval of an increasing number of clinically relevant predictive biomarkers in clinical settings. In the rapidly evolving scenario of predictive biomarkers, mandatory testing genes demonstrated a statistically significant clinical benefit in LC patients elected to molecular tests, but emerging biomarkers are under investigation to raise the bar in the clinical management of LC patients. To date, promising IHC-based predictive biomarkers emerged as potentially integrative tools in the panel of clinically approved biomarkers. On this basis, genomic, transcriptomic and proteomic data are gaining ground toward "3D" biology" supporting the need of a multidimensional analysis of tumor cells to clinically stratify LC patients. Here we sought to overview the most promising biomarkers investigated in clinical trials to be integrated into diagnostic panel of predictive biomarkers tools for NSCLC patients.

Racial and Ethnic Disparities in Receipt of ERBB2-Targeted Therapy for Breast Cancer, 2010-2020

Importance

Among older women (aged ≥50 years) with ERBB2 (formerly HER2 or HER2/neu)-positive breast cancer, research has shown racial and ethnic disparities in access to ERBB2-targeted therapies, with Black women receiving treatment at lower rates than their White counterparts.

Objective

To examine racial and ethnic disparities in receipt of ERBB2-targeted therapies and changes in receipt over time.

Design, Setting, and Participants

This retrospective cohort study used Surveillance, Epidemiology, and End Results-Medicare linked data from January 1, 2010, to December 31, 2020. Beneficiaries who were diagnosed with ERBB2-positive breast cancer between 2010 and 2019, were aged 66 years or older at diagnosis, were continuously enrolled in Medicare Parts A and B in the 12 months before and after diagnosis, and had localized or regional stage disease at diagnosis were included. Data were analyzed from February through September 2024.

Exposure

Race and ethnicity defined as non-Hispanic Black or African American, Hispanic, or non-Hispanic White.

Main Outcome and Measures

The primary outcome was receipt of ERBB2-targeted therapies in the 12 months after diagnosis of ERBB2-positive breast cancer. Modified Poisson regression was used to evaluate the probability of receiving ERBB2-targeted therapy by race and ethnicity.

Results

Among 12 765 beneficiaries with ERBB2-positive breast cancer (median [IQR] age, 74 [69-80] years; 99.2% female), 8.1% were of Black, 6.9% Hispanic, and 85.0% White race and ethnicity, and 54.2% received ERBB2-targeted therapy. The overall proportion who received ERBB2-targeted therapies increased from 41.3% in 2010-2011 to 64.3% in 2018-2019. Compared with White patients, Black patients had a lower likelihood of receiving ERBB2-targeted therapies in 2010-2011 (adjusted risk ratio [ARR], 0.81; 95% confidence limit [CL], 0.68-0.97), as did Hispanic patients (ARR, 0.75; 95% CL, 0.62-0.92). Racial and ethnic disparities in receipt of ERBB2-targeted therapies narrowed over time, with no significant differences observed across racial and ethnic groups in 2018-2019 for Black patients (ARR, 0.97; 95% CL, 0.87-1.08) and Hispanic patients (ARR, 1.05; 95% CL, 0.95-1.16).

Conclusions and Relevance

These findings suggest a narrowing of racial and ethnic disparities in receipt of ERBB2-targeted therapies over time among older Medicare beneficiaries with ERBB2-positive breast cancer. Future research is needed to understand the practices that contributed to the narrowing of racial and ethnic disparities and to develop implementation strategies to effectively improve the quality and equity of breast cancer care.

Precision medicine in Salivary Gland Carcinoma: Insights from breast and prostate cancer

Salivary Gland Carcinomas (SGC) are a heterogeneous group of diseases with varied histologies, biology, clinical behaviors, and therapeutic approaches. The World Health Organization classifies SGCs into Low Aggression and High Aggression categories. Due to their rarity and unique biology, managing SGCs is challenging, often requiring expert histological diagnosis and treatment based on low-level evidence. Despite recent international guidelines, several critical aspects of SGC management remain unresolved, in particular regarding systemic treatment. Recent discoveries of molecular alterations, such as HER2 amplification, and AR overexpression, have provided diagnostic, prognostic, and predictive biomarkers for alternative treatments. While some targeted treatment have corresponding EMA-approved therapies, others do not. Treatment strategies are further complicated by synchronous alterations, such as AR-positive SGCs with concomitant HER2 amplification. Open questions remain on the optimal use of these drugs, whether in early-stage disease, post-surgery, or in palliative settings. Given the rarity of the disease and the consequent lack of high quality data in literature, it is of importance a cross-fertilization process from other, more common disease such as breast and prostate cancers. In the current narrative review we analyze current evidence on the targeted treatment on salivary gland carcinomas and shared features with breast and prostate cancer.

Sortilin-Mediated Rapid, Precise and Sustained Degradation of Membrane Proteins via mRNA-Encoded Lysosome-Targeting Chimera

Recent advances in lysosome-targeting degradation technologies have introduced strategies to regulate therapeutic membrane proteins (MPs), potentially transforming treatment paradigms. However, challenges persist, including limited degradation precision due to the broad distribution of lysosome-targeting receptors (LTRs), as well as the high cost and complexity of recombinant protein production or chemical synthesis. Herein, it identifies sortilin as a promising LTR, highly expressed in malignancies but minimally present in healthy tissues outside the nervous system. Using AlphaFold-Multimer, it screened for a specific non-endogenous protein binder to sortilin and developed a modular, mRNA-encoded lysosomal targeting chimera (MedTAC) strategy, enabling rapid design and precise degradation of oncogenic MPs. In a breast cancer-bearing mouse model, a single low dose of MedTACPTK7 (0.5 mg kg-1) reduced protein tyrosine kinase-7 (PTK7) levels by up to 80% within 24 h, with sustained degradation of 44% at 72 h, demonstrating excellent pharmacokinetics. MedTACPTK7 significantly extended survival to over 50 days without systemic toxicity, compared to 20-30 days in controls. This MedTAC strategy establishes sortilin as a selective and efficient shuttle for targeted protein degradation, offering a scalable, rapidly producible platform for biochemical research and precise therapeutic applications.

An Optimized Droplet Digital PCR Assay for HER2 Copy Number Variation in Breast Cancer Based on Multi-reference Genes

Targeted therapy is essential for the 15-30% invasive breast cancer patients with human epidermal growth factor receptor 2 (HER2) over-expression. However, current HER2 diagnosing methods rely on complex manual works and highly subjective interpretations. To more accurately and objectively assess the HER2 amplification status of formalin fixed paraffin embedded (FFPE) samples, a droplet digital PCR (ddPCR) assay based on multi-reference genes was developed. We established a four-fluorescence ddPCR assay using breast cancer cell lines (T-47D and SK-BR-3) and validated it on 101 clinical breast cancer FFPE samples. Compared to clinicopathological results, the ddPCR assay based on two out of three reference genes demonstrated superior sensitivity (82.6%), specificity (98.7%), and consistency (95.0%) in determining HER2 status over assays using single or three reference genes. Whole genome sequencing of the abnormal cases further confirmed that the ddPCR assay outperformed clinical immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and quantitative PCR (qPCR) in accuracy. Our findings demonstrate that the multi-reference gene ddPCR assay significantly improves the accuracy of HER2 status detection and reduces errors associated with chromosome 17 abnormalities. This method holds promise as a complementary or alternative approach to conventional IHC and FISH testing in tissue biopsies and is also feasible for liquid biopsies.

Not All HER2-Positive Breast Cancers Are the Same: Intratumoral Heterogeneity, Low-Level HER2 Amplification, and Their Impact on Neoadjuvant Therapy Response

HER2 positive breast cancers are frequently treated with neoadjuvant anti-HER2 and chemotherapy (NACT). However, treatment response varies, with a subset of tumors showing high residual cancer burden (RCB). This study investigates the relationship between HER2 immunohistochemical (IHC) intratumoral heterogeneity (ITH), low level HER2 amplification, and tumor response to NACT. A total of 205 post-NACT HER2 positive breast carcinomas with available RCB results were classified into five HER2 groups: IHC 3+ (HER2 IHC positive, no FISH performed), Group 1-High (FISH HER2 copies >8 or HER2/CEP17 ratio >4), Group 1-Intermediate (HER2 copies > 6 to 8 or ratio > 3 to 4), Group 1-Low (HER2 copies 4 to 6 and ratio 2 to 3), and Group 3 (HER2 copies ≥ 6 and ratio < 2). Low level HER2 amplification, collectively designated as HER2 copies 4-8 or HER2/CEP17 ratio <4, was associated with reduced response to HER2-targeted therapy and higher RCB post-NACT. HER2 IHC ITH, defined as the presence of at least three distinct staining intensities with at least 10% of tumor cells exhibiting weak or no staining, was significantly more prevalent in low level HER2 amplification groups (Gp1-Int: 93.3%, Gp1-Low: 87.5%, Gp3: 80.0%) compared to high level amplification groups (IHC 3+: 24.7%, Gp1-High: 28.6%) (p<.001). Both low level HER2 amplification and HER2 IHC ITH, regardless of hormone receptor status, were independently associated with poor treatment response, and tumors demonstrating both features had the highest likelihood of low therapeutic efficiency. These findings suggest that both low level HER2 amplification and HER2 IHC ITH contribute to poor NACT response and may warrant alternative therapeutic strategies. Further prospective studies are needed to refine the clinical significance of low level HER2 amplification and IHC ITH, particularly in the context of novel HER2-targeted therapies such as antibody-drug conjugates.

Association of statin use on survival outcomes of patients with early-stage HER2-positive breast cancer in the APHINITY trial

PURPOSE

There is evidence that statins might improve the outcome of patients with breast cancer. The role of statins in patients with early HER2-positive breast cancer is unknown. Therefore, we explored the association between statin use and survival outcomes in early HER2-positive breast cancer patients in the phase III APHINITY trial (adjuvant pertuzumab/trastuzumab).

METHODS

All patients (intent-to-treat population, n = 4804) were included (6.2 years median follow-up database). The primary objective was to investigate the association of statin use on invasive disease-free survival (IDFS), distant relapse-free interval (DRFI), and overall survival (OS). Patients who received statins at baseline, or started statins within 1 year from randomization were considered statin users. Survival curves were estimated using the Kaplan-Meier method. We used a Cox proportional hazards model for multivariate analysis.

RESULTS

Overall, 423 (8.8%) patients were classified as statin users. They were older, more often postmenopausal, had a higher body mass index, more often diabetes, hypertension, coronary heart disease and hyperlipidemia, had smaller sized tumors, were treated more often with breast conserving surgery, and less often with anthracycline-containing regimens. Overall, 508 IDFS events (12.8% among statin users and 10.4% among non-statin users) and 272 deaths (8.5% and 5.4%, respectively) occurred. In multivariate analysis, statin use was not associated with IDFS (HR, 1.11; 95% CI, 0.80-1.52), DRFI (HR, 1.21; 95% CI, 0.81-1.81) nor OS (HR, 1.16; 95% CI, 0.78-1.73).

CONCLUSION

In APHINITY, statin use was not associated with improved survival outcomes. These results must be interpreted with caution due to the exploratory nature of the analysis and the associated limitations.

ErbB2/HER2-targeted CAR-NK cells eliminate breast cancer cells in an organoid model that recapitulates tumor progression

Chimeric antigen receptor-engineered NK cells hold promise for adoptive cancer immunotherapy. In one such approach, the ErbB2 (HER2)-specific CAR-NK cell line NK-92/5.28.z is under investigation as an off-the-shelf therapy in a phase I trial in glioblastoma patients. To evaluate activity of NK-92/5.28.z cells against ErbB2-positive breast cancer, here we developed an organoid model derived from CKP mice that allows conditional activation of oncogenic driver mutations. Expression of ErbB2 and Cre recombinase in CKP mammary epithelial cells induced malignant transformation, with the resulting EC-CKP cells characterized by neoplastic morphology, loss of p53, and constitutive activation of the MAP kinase pathway. NK-92/5.28.z cells demonstrated potent CAR-mediated cytotoxicity against EC-CKP organoids, with tumor cell lysis dependent on exposure time and organoid size. In vivo passaging of EC-CKP organoids revealed cellular plasticity and induced an EMT phenotype associated with increased resistance to standard therapies. Importantly, NK-92/5.28.z cells retained high and specific cytotoxicity against these breast cancer cells in vitro and in an aggressive organoid-based in vivo mouse model that reflects advanced-stage disease. Our data highlight the therapeutic potential of NK-92/5.28.z cells against ErbB2-positive breast cancer, supporting their further development toward clinical application.

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.

Enhanced antibody-mediated cellular cytotoxicity of germline-like anti-HER2 antibodies through a point mutation in complementarity-determining regions

Human epidermal growth factor receptor 2 (HER2) is highly overexpressed on the surface of breast cancer cells, presenting an attractive target for therapeutic antibodies. Antibody-dependent cellular cytotoxicity (ADCC) is a central mechanism underlying the antitumor activities of anti-HER2 monoclonal antibodies. Here, we engineered Ab5, a germline-like anti-HER2 monoclonal antibody derived from a naïve human antibody library. Our aim was to enhance the ADCC properties of Ab5 by affinity maturation. Through an in silico aided mutagenesis analysis, we identified an Ab5 mutant termed Ab5m, exhibiting enhanced affinity compared with the parental Ab5. Computational modeling predicted that a crucial interacting residue, aspartic acid 31 on the complementarity-determining region 1 of the heavy chain involved in the important charged interactions with HER2 domain II. Substitution of aspartic acid with glutamic acid decreased the interaction energies, resulting in a remarkable affinity enhancement of Ab5m-scFv (KD = 0.2 nM) compared with parental Ab5-scFv (KD = 1.5 nM). This affinity maturation translated into the obvious improvement in ADCC and notable enhancement of tumor ablation in vivo, either alone or in combination with anti-B7-H3 antibodies. These findings suggest that the potential of affinity optimization as a strategy to enhance the ADCC properties of human germline antibodies.

PAK5 promotes the trastuzumab resistance by increasing HER2 nuclear accumulation in HER2-positive breast cancer

Nuclear HER2 (N-HER2) predicts resistance to HER2-targeted therapy and poor prognosis of breast cancer patients, and the underlying mechanisms remain unclear. Here, we show that high expression of p21-activated kinase 5 (PAK5) is associated with HER2-targeted therapy resistance and poor outcomes of breast cancer patients. Excitingly, we find an increase in N-HER2 protein expression in patients with high PAK5 expression, who demonstrate resistance to trastuzumab treatment. PAK5 phosphorylates methyltransferase METTL14 on serine 399 to enhance m6A modification of lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), leading to increased MALAT1 stability. The stabilized MALAT1 inhibits ubiquitin-proteasomal degradation of the N-HER2 by affecting the interaction of deubiquitinase USP8 and N-HER2, thereby promoting N-HER2 accumulation. Moreover, HER2 upregulates the expression of PAK5 and MALAT1, activating the HER2-MALAT1 positive feedback loop. Importantly, PAK5 promotes the therapeutic resistance of HER2-positive breast cancer cells by increasing N-HER2 protein both in vitro and vivo. These findings highlight PAK5 as a therapeutic target for combating trastuzumab resistance in HER2-positive breast cancer.

Machine learning prediction of HER2-low expression in breast cancers based on hematoxylin-eosin-stained slides

BACKGROUND

Treatment with HER2-targeted therapies is recommended for HER2-positive breast cancer patients with HER2 gene amplification or protein overexpression. Interestingly, recent clinical trials of novel HER2-targeted therapies demonstrated promising efficacy in HER2-low breast cancers, raising the prospect of including a HER2-low category (immunohistochemistry, IHC) score of 1 + or 2 + with non-amplified in-situ hybridization for HER2-targeted treatments, which necessitated the accurate detection and evaluation of HER2 expression in tumors. Traditionally, HER2 protein levels are routinely assessed by IHC in clinical practice, which not only requires significant time consumption and financial investment but is also technically challenging for many basic hospitals in developing countries. Therefore, directly predicting HER2 expression by hematoxylin-eosin (HE) staining should be of significant clinical values, and machine learning may be a potent technology to achieve this goal.

METHODS

In this study, we developed an artificial intelligence (AI) classification model using whole slide image of HE-stained slides to automatically assess HER2 status.

RESULTS

A publicly available TCGA-BRCA dataset and an in-house USTC-BC dataset were applied to evaluate our AI model and the state-of-the-art method SlideGraph + in terms of accuracy (ACC), the area under the receiver operating characteristic curve (AUC), and F1 score. Overall, our AI model achieved the superior performance in HER2 scoring in both datasets with AUC of 0.795 ± 0.028 and 0.688 ± 0.008 on the USCT-BC and TCGA-BRCA datasets, respectively. In addition, we visualized the results generated from our AI model by attention heatmaps, which proved that our AI model had strong interpretability.

CONCLUSION

Our AI model is able to directly predict HER2 expression through HE images with strong interpretability, and has a better ACC particularly in HER2-low breast cancers, which provides a method for AI evaluation of HER2 status and helps to perform HER2 evaluation economically and efficiently. It has the potential to assist pathologists to improve diagnosis and assess biomarkers for companion diagnostics.

Simultaneously induce apoptosis and inhibiting metastasis of Triple negative breast cancer Enabled by a highly potent NIR fluorescent inhibitor

Triple-negative breast cancer (TNBC) is a cancerous tumor that poses a global threat to women's lives and health. Currently, chemotherapy is the preferred treatment for advanced TNBC. In this work, we have identified a novel NIR fluorescent inhibitor, SWMU690, which can effectively inhibit the proliferation of TNBC at low doses. The half-maximal inhibitory concentration (IC50) values of SWMU690 against the MDA-MB-231, 4 T1, and T47D cell lines were determined to be 104 nM, 509.4 nM, and 206 nM, respectively. We found that SWMU690 specifically localized in mitochondria to trigger mitochondria-mediated intrinsic apoptotic pathways. Furthermore, SWMU690 can suppress the production of ATP to inhibit TNBC metastasis. This study demonstrated the advantage of disrupting the function of mitochondria in inhibiting the proliferation and metastasis of TNBC, and may have other applications in the treatment of other malignant tumors.

High Expression of Complement 3 Enhances the Efficacy of Neoadjuvant Chemotherapy Prior to Oncoplastic Surgery for HER2-Positive Breast Cancer

Background: Neoadjuvant chemotherapy for breast cancer (BC) improves patient prognosis, but its efficacy is hindered by the disease's high heterogeneity. This study enhances effectiveness of targeted therapy to improve clinical outcomes. Methods: This study enrolled 335 patients from three centers. Differentially expressed genes were identified using DESeq2, and Venn analysis was applied to identify hub Complement genes. Hub gene expression was validated through public databases and IHC in real-world samples. In addition, associations between these genes and clinical factors were evaluated. Survival analysis, using the log-rank test, assessed overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI) as end points. The authors also locate hub Complement 3 gene position by immunofluorescence. Results: The study identified C3 as a hub Complement gene associated with trastuzumab sensitivity. C3 shows higher expression in normal than tumor tissues. C3 was highly expressed in HER2-negative and early-stage BC, but showed no differences in lymph node or metastasis subgroups. High C3 expression correlated with better OS, DSS, and PFI, particularly in HER2+ patients. IHC analysis confirmed higher C3 expression in normal tissues with the lowest in triple-negative BC. Immunofluorescence findings suggest that C3 recruits complement receptor 2 to enhance trastuzumab efficacy in HER2+ patients. Conclusions: This finding highlights the potential of complement 3 to improve therapeutic outcomes and pave the way for more personalized treatment strategies in BC.

HERmione: Understanding the Needs of Patients Living with Metastatic HER2-Positive Breast Cancer Through a Cross-Sectional Survey in Parallel with Patients and Oncologists

BACKGROUND/OBJECTIVES

HER2-positive metastatic breast cancer continues to have a significant impact on patients' lives. The HERmione project was conducted in France to identify patients' needs for support and information, understand services offered, and identify differences in the perception of burden between patients and oncologists.

METHODS

Between July and October 2022, 273 patients with HER2-positive metastatic breast cancer and 40 oncologists were surveyed. The mean age of patients was 52 years, with most receiving treatment at specialized cancer centers (38%) or other public hospitals (34%).

RESULTS

The survey revealed a substantial burden of the disease and treatment in patients, perceptions that differed from those of oncologists. Both the physical and mental well-being of the patients were below average. Despite the burden of the disease, patients lacked access to many types of support, particularly support with sexual well-being. Additionally, 60% of patients did not have access to nursing support. Patients had high expectations regarding access to information but often did not know where to access this information. Despite this, they still exhibited treatment preferences.

CONCLUSIONS

These findings suggest that enhanced communication is critical to ensure that patients receive adequate support. Nursing support could improve patient-oncologist communication and thereby enhance patient well-being. Finally, to meet patient expectations regarding information access, a broader array of support tools should be offered.

Fibroblast growth factor receptor four inhibitor FGF401 improves the efficacy of trastuzumab in FGFR4-overexpressing breast cancer cells

Breast cancer is the most common cancer among women. Among them, human epidermal growth factor receptor-positive (HER2+) breast cancer is more malignant. Fortunately, many anti-HER2 drugs are currently used in clinical treatments to increase patient survival. However, some HER2+ patients (~15%) still develop drug resistance after receiving trastuzumab treatment, leading to treatment failure. Using CCLE and METABRIC database analyses, we found that fibroblast growth factor receptor 4 (FGFR4) mRNA was highly detected in tumors from HER2+ breast cancer patients (p < .001) and was associated with poorer survival in breast cancer patients. Through retrospective immunohistochemical staining analysis, we detected higher expression of FGFR4 protein in breast cancer tissues collected from patients who were resistant to trastuzumab therapy compared with breast cancer patients who responded to treatment. An FGFR4 inhibitor (FGF401) effectively inhibits tumor growth in trastuzumab-insensitive patient-derived xenograft (PDX) tumor-bearing mice. For molecular mechanism studies, we demonstrated that HER2/FGFR4 protein complexes were detected on the cell membrane of the tumor tissues in these trastuzumab-insensitive PDX tumor tissues. After trastuzumab treatment in these drug-resistant breast cancer cells, FGFR4 translocates and enters the nucleus. However, trastuzumab-induced nuclear translocation of FGFR4/HER2-intracellular domain protein complex in trastuzumab-resistant cancer cells is blocked by FGF401 treatment. We believe that FGFR4 overexpression and complex formation with HER2 can serve as molecular markers to assist clinicians in identifying trastuzumab-resistant tumors. Our results suggest that FGF401 combined with trastuzumab as adjuvant therapy for patients with trastuzumab-resistant breast cancer may be a potential new treatment strategy.

Comparison of Clinicopathological Characteristics for HER2-Null, HER2-Ultralow and HER2-Low Breast Cancer: A Single-Center Study

Background and Objectives: A recent clinical trial has demonstrated that breast cancer with low-HER2 expression levels responds to trastuzumab deruxtecan treatment. This has prompted a re-evaluation of HER2-targeted therapies in the HER2-negative group. Further research is required in the form of more detailed information about HER2-negative breast cancers with HER2-null, HER2-ultralow, and HER2-low subgroups. This study represents a novel approach to this field. Materials and Methods: HER2-negative breast cancer patients were classified into three groups as HER2-null, HER2-ultralow, and HER2-low. A comparison of clinicopathological features was analyzed retrospectively. Results: Of 722 patients, 22.3% were HER2-null, 23.7% were HER2-ultralow, 54.0% were HER2-low. While two-thirds of all the patients were evaluated as having T2 tumors, T4 tumors constituted 2.4%. Among HER2-negative cases, 11.8% were triple-negative and 88.2% were hormone-positive. The mean tumor diameter was 0.57 cm larger in the HER2-ultralow group than in the HER2-null group and 0.34 cm larger in the HER2-low group than in the HER2-null group. HER2-null tumors tend to be smaller. The HER2-low group was more likely to relapse than the HER2-null group. There were no significant differences in the distribution of hormone positivity or negativity (TNBC) among the groups; they accounted for 89.2% and 10.8% of all cases, respectively. Conclusions: HER2-negative breast cancer is a heterogeneous disease and deserves a detailed review in terms of diagnosis and treatment. HER2-ultralow tumors are larger in size and have a prognosis comparable to HER2-null tumors. HER2-low tumors tend to recur much more frequently and with poorer outcomes. In this field, new therapeutic approaches may result in better outcomes.

A new, immunocompetent brain-metastatic mouse model of HER2-positive breast cancer

Brain metastasis is a common and devastating complication of cancer that affects over 50% of HER2-positive (HER2+) breast cancer patients. The lack of effective long-term treatment options for brain metastasis significantly increases morbidity and mortality among these patients. Therefore, understanding the underlying mechanisms that drive brain metastasis is critically important for developing new strategies to treat it effectively. Genetically engineered mouse models (GEMMs) of HER2+ breast cancer have been instrumental in understanding the development and progression of HER2+ breast cancer. However, the GEMM models for HER2+ breast cancer do not develop brain metastasis and are not suitable for the study of brain metastasis. We therefore developed a fully immunocompetent mouse model of experimental brain metastasis in HER2+ breast cancer by injecting a murine HER2/neu-expressing mammary-tumor-cell line into the arterial circulation of syngeneic FVB/N mice followed by isolation of brain-metastatic derivatives through in-vivo selection. By this in-vivo serial passaging process, we selected highly brain-metastatic (BrM) derivatives known as neu-BrM. Notably, after intracardiac injection, neu-BrM cells generated brain metastasis in 100% of the mice, allowing us to study the later stages of metastatic progression, including cancer-cell extravasation and outgrowth in the brain. Analogous to human brain metastasis, we observed reactive gliosis and significant immune infiltration in the brain tissue of mice injected with neu-BrM cells. We further confirmed that brain-metastatic lesions in the neu-BrM model express HER2. Consistently, we found that the brain-metastatic burden in these mice can be significantly reduced but not eliminated with tucatinib, an FDA-approved, blood-brain-barrier-penetrant HER2 inhibitor. Therefore, the neu-BrM HER2+ breast cancer model can be used to investigate the roles of innate and adaptive immune-system components during brain-metastatic progression and the mechanisms of HER2-therapy response and resistance.

Exploring Novel Therapeutic Targets in Breast Cancer via Comprehensive Omics Profiling and Experimental Verification

BACKGROUND

Breast cancer is the leading cause of cancer-related deaths among women worldwide. Deciphering the molecular mechanisms of breast cancer is crucial for developing targeted therapeutic approaches.

METHODS

This study analyzed gene expression profiles from the Gene Expression Omnibus (GEO) database to identify differentially expressed genes (DEGs) in breast cancer. Mendelian randomization (MR) analysis was then employed using publicly available eQTL databases to evaluate potential causal relationships between these DEGs and breast cancer. Enrichment analyses were further conducted to explore their functional significance. Furthermore, external validation of co-expressed genes was conducted using The Cancer Genome Atlas (TCGA) database. In vitro functional assays and drug sensitivity analyses were performed on selected target genes to validate their roles in breast cancer pathogenesis and treatment.

RESULTS

A total of 1052 upregulated and 1380 downregulated genes were identified in breast cancer. Additionally, MR analysis revealed 12 significant co-expressed genes potentially contributing to breast cancer pathogenesis. These genes were primarily enriched in lipid metabolism and immune responses via regulating microRNA functions and AMPK signaling. Validation through the TCGA database confirmed differential expression of these genes in breast cancer tissues. Strikingly, functional assays of the less-reported genes DNASE2 and ATOH8 demonstrated their involvement in breast cancer pathogenesis through modulating proliferation, migration, and invasion of cancer cells. Notably, several commonly used clinical drugs for breast cancer management, such as 5-Fluorouracil, exhibited dramatically increased sensitivity to DNASE2 and ATOH8 expression.

CONCLUSIONS

Our study provides novel insights into the molecular basis of breast cancer pathogenesis and identifies promising therapeutic strategies for this condition.

Detection of Human Circulating and Extracellular Vesicle-Derived miRNAs in Serum of Humanized Mice Transplanted with Human Breast Cancer (HER2+ and TNBC) Cells-A Proof of Principle Investigation

Humanized tumor mice (HTM) allow for preclinical cancer treatment studies of breast cancer (BC) under human-like conditions. This study utilized HTM for the first time to investigate potential miRNA biomarker candidates for treatment response in sera and extracellular vesicles (EVs), following X-irradiation and atezolizumab (anti-PD-L1) treatment. We identified the changes of human-specific miRNAs (miR-23b-3p and miR-155-5p) after irradiation and anti-PD-L1 treatment in HTMs with human epidermal growth factor receptor 2 positive (HER2+ BC) and triple-negative breast cancer (TNBC). The high degree of conserved, circulating free miRNA in mice and men represents a challenge of our assay; however, miRNAs with ≥2 nucleotide mismatches can be employed for human-specific analysis, and even conserved miRNAs may be utilized under clearly defined conditions of human tumor growth in HTM. A comparative analysis of extracellular vesicle miRNA cargo and free-circulating serum miRNAs revealed several exosome-specific miRNAs (miR-29b-3p, miR-34c-5p, miR-203a-3p, miR-378g, and miR-382-5p) in HTMs, which are known to play roles in BC. Our findings demonstrate that HTMs are a suitable model to identify treatment-induced changes in free-circulating and exosomal miRNAs that influence tumor progression and immunological tumor defense, both locally and at distant sites. This study presents a proof-of-principle approach to analyzing cell-free nucleotides and exosomes in a human-like, preclinical in vivo setting. Further refinements are necessary to enhance the sensitivity and the specificity of the HTM-based approach.

A Comprehensive Review About the Use of Monoclonal Antibodies in Cancer Therapy

Monoclonal antibodies (mAbs) targeting various pathways in cancer therapy play crucial roles in enhancing the immune system's ability to recognise and eliminate tumour cells. These therapies are designed to either block inhibitory immune checkpoint pathways or to target specific tumour cell markers for direct destruction. Additionally, mAbs can modulate the tumour microenvironment, enhance antibody-dependent cellular cytotoxicity, and inhibit angiogenesis, further amplifying their therapeutic impact. Below is a summary of monoclonal antibodies targeting key pathways, along with their indications and mechanisms of action, which are reviewed based on therapeutic mechanisms.

Enhanced Targeted Drug Delivery System to Control Avidity and Drug Encapsulation Using E2 Nanocages and SpyTag/SpyCatcher

Although antibody-drug conjugates offer advanced targeted anticancer therapy that overcomes the limitations of conventional chemotherapy and therapeutic antibodies, they are restricted in their capacity to carry multiple hydrophobic payloads. Protein nanocages have emerged as versatile therapeutic platforms for targeted drug delivery, offering advantages like precise molecular assembly, biocompatibility, and multivalent targeting. This study presents the development of engineered E2 nanocages functionalized with anti-HER2 single-chain variable fragments (scFv) using the SpyTag/SpyCatcher ligation system to achieve controlled scFv display valency. The results demonstrate that increasing anti-HER2 scFv valency enhances HER2 binding affinity via avidity effects, with the highest valency nanocages showing the highest binding avidity. Furthermore, cysteine residues were introduced into the E2 nanocages to enable conjugation with monomethyl auristatin E (MMAE) through maleimide chemistry, achieving efficient drug loading. The resulting MMAE-conjugated nanocages displayed potent, subnanomolar cytotoxicity in HER2-positive SKBR3 and BT-474 cell lines while sparing HER2-negative MDA-MB-231 cells at concentrations up to 1 nM. These results underscore the critical role of scFv valency in enhancing HER2 targeting and highlight the potential of E2 protein nanocages as specific, potent platforms for targeted cancer therapy. In this study, we developed an enhanced targeted drug delivery system using E2 nanocages and scFv with SpyCatcher/SpyTag ligation to regulate binding avidity and encapsulate hydrophobic drugs. The modular design and pH-sensitive dissociation of these nanocages establish a foundation for next-generation precision medicine strategies.

Anti-breast cancer activity of a novel genetically engineered fusion protein composed of HER2 affibody and proapoptotic peptide R8-KLA

HER2-positive breast cancer is an aggressive subtype with unfavorable prognoses. Although HER2-targeted agents represented by monoclonal antibodies have achieved remarkable success in the clinic, there are still a substantial number of patients with disease relapse. Recently, multifunctional fusion proteins obtained via genetic engineering technology have received much attention in targeted tumor therapy, especially in breast cancer. In this study, we genetically engineered a novel recombinant fusion protein, named HMK, which was designed as a bifunctional construct including the HER2-specific affibody ZHER2:342 for targeted receptor recognition, and a proapoptotic module featuring a cell-penetrating octa-arginine (R8) motif conjugated to an antimicrobial peptide KLA. High-purity HMK proteins were successfully obtained using E. coli expression system and Ni-Nitrilotriacetic acid affinity purification method. HMK exhibited higher cytotoxicity in HER2-positive breast cancer cells SK-BR-3 (IC50 of 8.36 ± 0.62 μM) compared to normal breast epithelial cells MCF-10A (IC50 of 32.40 ± 2.93 μM), demonstrating favorable selectivity. HMK induced apoptosis in SK-BR-3 cells via activating both endogenous and exogenous apoptotic pathways, as evidenced by the cleavage of Caspase 8, Caspase 9, Caspase 3, and PARP. Caspase inhibitor Z-VAD significantly reversed the function of HMK in SK-BR-3 cells, suggesting that caspase-dependent apoptosis was crucial for the anti-breast cancer activity of HMK. Our results suggested that HMK protein may have the potential to become a candidate molecule for HER2-positive breast cancer treatment.

HER2 testing: evolution and update for a companion diagnostic assay

Human epidermal growth factor receptor 2 (HER2; encoded by ERBB2) testing has been a cornerstone of patient selection for HER2-targeted therapies, principally in breast cancer but also in several other solid tumours. Since the introduction of HercepTest as the original companion diagnostic for trastuzumab, HER2 assessment methods have evolved substantially, incorporating various testing modalities, from western blots, immunohistochemistry and fluorescence in situ hybridization, to early chromogenic quantitative methods and, probably in the future, fully quantitative methods. The advent of highly effective HER2-targeted antibody-drug conjugates with clinical activity at low levels of HER2 expression, such as trastuzumab deruxtecan, has necessitated the re-evaluation of HER2 testing, particularly for HER2-low tumours. In this Review, we provide an in-depth overview of the evolution of HER2 testing, the current clinical guidelines for HER2 testing across various solid tumours, challenges associated with current testing methodologies and the emerging potential of quantitative techniques. We discuss the importance of accurately defining HER2-low expression for therapeutic decision-making and how newer diagnostic approaches, such as quantitative immunofluorescence and RNA-based assays, might address the limitations of traditional immunohistochemistry-based methods. As the use of HER2-targeted therapies continues to expand to a wider range of tumour types, ensuring the precision and accuracy of HER2 testing will be crucial for guiding treatment strategies and improving patient outcomes.

MHC class II-mediated spontaneous rejection of breast carcinomas expressing model neoantigens

BACKGROUND

Cancers persist despite expression of immunogenic neoantigens and ongoing antitumor immune responses. While some occult tumors likely are cleared by effective antitumor immune responses, the targeted antigens are not easily identifiable as those tumors spontaneously disappear.

METHODS

We used mouse models with a defined antigenic protein mimicking tumor-specific neoantigens to address the nature of these spontaneous anti-tumor immune responses.

RESULTS

BALB/c (H-2d ) mice challenged with BALB/c breast tumors expressing the rat-erbB2 oncoprotein succumb to their tumors despite ongoing immune responses targeting tumor-specific model antigens. Meanwhile, congenic BALB.B (H-2b ) and H-2d/H-2b F1 hybrid mice spontaneously eliminate genetically matched tumors in a major histocompatibility complex (MHC)-II dependent manner. Adoptive transfer and immune cell depletion strategies revealed CD4+ T cells and CD20+ B cells are crucial mediators of the protective response in H-2b mice. Furthermore, passive transfer of immune serum from mice rejecting their tumors confers resistance in tumor antigen-tolerant animals with an inversely proportional relationship between tumor outgrowth and the amount of rat-erbB2 specific antibody present in tumor-bearing mice. Introduction of the rat-erb2 ectodomain into other H-2b tumor models also promotes their spontaneous tumor rejection. Notably, the tumor microenvironments differ in rat-erbB2+ tumor-bearing BALB.B and BALB/c mice at the time of fate decision in the models reflecting the differences between effective and ineffective tumor immune responses.

CONCLUSIONS

We find that the effective antitumor immunity targeting neoantigens in these breast cancer models is determined by MHC-II-restricted presentation of optimal cancer-associated antigens. These responses are dependent on CD4+ T cells, B cells, and antigen-specific antibodies.

The Co-Expression and Cellular Location of HER Family Members, EGFRvIII, Putative Cancer Stem Cell Biomarkers CD44 and CD109 in Patients with Glioblastoma, and Their Impacts on Prognosis

BACKGROUND/OBJECTIVES

The aberrant expression and activation of HER family members is a known major oncogenic pathway for the proliferation, progression, and metastasis of a wide range of human malignancies. In this study, our aim was to examine the relative expression and prognostic significance of all members of the HER family, the type III EGFR mutant (EGFRvIII), and the putative stem cell markers CD44 and CD109 in patients with glioblastoma.

METHODS

The expression levels of wild-type EGFR (wtEGFR), HER2, HER3, HER4, EGFRvIII, CD44, and CD109 were determined in tumour specimens from 80 patients by immunohistochemistry. The staining was scored based on the percentage of positive tumour cells, the intensity, and the cellular location of immunostaining. The association between the expression level of the biomarkers and patient overall survival was evaluated using Chi-squared, Kaplan-Meier survival curves, and log-rank tests.

RESULTS

At a cut-off value of ≥5% with positive staining, 46% (wtEGFR), 75% (HER2), 19% (HER3), 71% (HER4), 85% (EGFRvIII), 95% (CD44), and 16% (CD109) of the cases were positive for these biomarkers. Interestingly, at the same cut-off value, the expression of wtEGFR in these patients was accompanied by co-expression with HER2 (35%), HER3 (0%), HER4 (30%), EGFRvIII (36%), CD44 (44%), HER2/EGFRvIII (28%), HER2/CD44 (31%), and EGFRvIII/CD44 (36%). In addition, the expression of EGFRvIII was accompanied by co-expression with HER2 (65%), HER3 (15%), HER4 (63%), CD44 (83%), CD109 (16%), wtEGFR/HER2 (28%), and 55% of the cases had co-expression of EGFRvIII/HER2/HER4/CD44. With the exception of HER2 expression, at cut-off values of ≥5% of tumour cells with positive staining, which was associated with better overall survival [HR = 0.57 (p = 0.038), HR = 0.56 (p = 0.034)], there was no significant association between the expression of other members of the HER family, EGFRvIII, CD44, and CD109 on the overall survival in both univariate and multivariate analysis. Conclusions Our results suggest that the co-expression of different members of the HER family, with EGFRvIII, CD44, and CD109, occurs in patients with glioblastoma. As the results of therapy with EGFR inhibitors have not been encouraging in patients with a brain tumour, further investigation should determine whether the co-expression of such biomarkers can be of predictive value for the response to the therapy with various types of HER inhibitors and their potential as therapeutic targets for co-targeted therapy.

Novel strategies in breast cancer management: From treatment to long-term remission

Breast cancer (BC) is the most common malignancy among women and a leading cause of cancer-related mortality worldwide. Although improvements in early detection and therapy have been made, metastatic breast cancer (mBC) continues to be an incurable disease. Although existing treatments can prolong survival and enhance quality of life, they do not provide a definitive cure. Targeted therapies have significantly improved outcomes, particularly for subtypes such as human epidermal growth factor receptor 2 (HER2)-positive and hormone receptor (HR)-positive (HR+) BC. Key innovations include antibodydrug conjugates (ADCs) and next-generation endocrine therapies. ADCs combine monoclonal antibodies with cytotoxic agents, allowing targeted delivery to tumor cells while minimizing systemic toxicity. Immunotherapy is emerging as a promising approach for aggressive subtypes, such as triple-negative breast cancer (TNBC). Strategies under investigation include chimeric antigen receptor T-cell (CAR-T) therapy, tumor-infiltrating lymphocyte (TIL) therapies, and natural killer (NK) cell treatments, all aimed at enhancing the ability of the immune system to target and eliminate resistant tumor cells. Tissue engineering, particularly hydrogel-based delivery systems, offers the potential for localized treatment. These systems enable the controlled release of therapeutic agents or immune cells directly to the tumor site, supporting tissue regeneration and enhancing immune surveillance to reduce recurrence. Despite these advancements, challenges remain, including treatment resistance, the immunosuppressive tumor microenvironment, and high costs. Overcoming these barriers requires further innovation in drug delivery systems and a deeper understanding of tumor biology.

Digitally quantified area of residual tumor after neoadjuvant chemotherapy in HER2-positive breast cancer

BACKGROUND

The area of residual tumor (ART) is a quantitative method for assessing tumors after neoadjuvant chemotherapy (NAC). This study evaluated whether ART can identify a favorable prognosis group in patients with HER2-positive surgically resected breast cancer and residual tumors post-NAC.

METHODS

We retrospectively reviewed patients with HER2-positive who underwent surgery after NAC, including trastuzumab, from 2005 to 2022 at our institution. ART was assessed at the maximum cut surface of the residual primary tumor using digital pathology images. Receiver operating characteristic curve analysis determined ART-Low and ART-High cutoffs, excluding ART-0 (0 mm2) patients.

RESULTS

Of the 219 patients, 82 had ART greater than 0 mm2. The median follow-up was 90.2 months. The number of patients in the ART-0, ART-Low (0 < ART ≤ 4.0 mm2), and ART-High (> 4.0 mm2) groups were 137, 39, and 43, respectively. The ART-Low group showed significantly shorter event-free survival compared to the ART-0 group (HR 3.50, 95% CI 1.52-8.06), and the ART-High group also tended toward poorer prognosis (HR 2.31, 95% CI 0.89-5.97). However, there was no significant difference in prognosis between the ART-Low and ART-High groups.

CONCLUSIONS

The current study suggests that even minimal residual tumor cells in the primary site can significantly impact on prognosis in HER2-positive early breast cancer.

Bone-Induced HER2 Promotes Secondary Metastasis in HR+/HER2- Breast Cancer

SIGNIFICANCE

Given the urgent need for alternative strategies to block metastasis progression, we demonstrate that blocking HER2-mediated secondary metastasis improves clinical outcome and establish HER2 as a biomarker for bone metastasis in patients with initial HR+/HER2- breast cancer, which represents ∼70% of all cases.

Tumor‑associated neutrophils: Critical regulators in cancer progression and therapeutic resistance (Review)

Cancer is the second leading cause of death among humans worldwide. Despite remarkable improvements in cancer therapies, drug resistance remains a significant challenge. The tumor microenvironment (TME) is intimately associated with therapeutic resistance. Tumor‑associated neutrophils (TANs) are a crucial component of the TME, which, along with other immune cells, play a role in tumorigenesis, development and metastasis. In the current review, the roles of TANs in the TME, as well as the mechanisms of neutrophil‑mediated resistance to cancer therapy, including immunotherapy, chemotherapy, radiotherapy and targeted therapy, were summarized. Furthermore, strategies for neutrophil therapy were discussed and TANs were explored as potential targets for cancer treatment. In conclusion, the need to explore the precise roles, recruitment pathways and mechanisms of action of TANs was highlighted for the purpose of developing therapies that precisely target TANs and reverse drug resistance.

TUXEDO-4: phase II study of trastuzumab-deruxtecan in HER2-low breast cancer with new or progressing brain metastases

CLINICAL TRIAL REGISTRATION

NCT06048718 (clinicaltrials.gov); 2023 -506,702-39-00 (EudraCT number).

A novel anti-HER2/EGFR bispecific antibody-drug conjugate demonstrates promising antitumor efficacy and overcomes resistance to HER2- or EGFR-targeted ADCs

HER2 and EGFR are frequently co-expressed in various tumors. While antibody-drug conjugates (ADCs) targeting HER2, such as T-DM1 and T-Dxd, have shown remarkable antitumor effects in clinical responses, their effectiveness is constrained by drug resistance. EGFR amplification or high expression is one of the factors that lead to resistance against HER2-targeted ADCs. Likewise, the amplification of HER2 may lead to the development of resistance to EGFR-targeted therapies. To overcome these challenges, we, therefore, developed a bispecific antibody (B2C4) that targets HER2 and EGFR. B2C4 exhibited strong binding affinity and internalization activity in tumor cells with high expression of HER2 and EGFR, as well as in those with high expression of either target. B2C4 was then conjugated with vc-MMAE to create a bispecific ADC (B2C4-MMAE) with an average DAR of 4.05. By effectively engaging both arms of the bispecific ADC, B2C4-MMAE demonstrated significant antitumor activity in tumor cells and animal models that were unresponsive HER2- or EGFR-targeted ADCs. B2C4-MMAE could serve as an alternative therapeutic option for tumors that are resistant to single-target treatments. Additionally, B2C4-MMAE exhibited potential in treating tumors resistant to T-Dxd, underscoring its promise as a treatment for challenging cases.

Targeting HSP90AA1 to overcome multiple drug resistance in breast cancer using magnetic nanoparticles loaded with salicylic acid

Multiple drug resistance (MDR) remains a major obstacle in effective breast cancer chemotherapy. This study explores the role of HSP90AA1 in driving MDR and evaluates the potential of magnetic nanoparticles (Fe3O4@SA) loaded with salicylic acid (SA) to counteract drug resistance. A comprehensive screening of 200 SA-related target genes identified nine core genes, including HSP90AA1. Pharmacophore analysis revealed that SA interacts with HSP90AA1, a key regulator of mitochondrial K+ channels. Fe3O4@SA nanoparticles demonstrated efficient cellular uptake and lysosomal escape, markedly improving the chemosensitivity of resistant breast cancer cells and promoting apoptosis. In vivo experiments further confirmed the anticancer efficacy of Fe3O4@SA, highlighting its potential as a promising therapeutic strategy to overcome MDR in breast cancer.

LINC01235 Promotes Clonal Evolution through DNA Replication Licensing-Induced Chromosomal Instability in Breast Cancer

Despite the development of HER2-targeting drugs such as trastuzumab and T-DXd, treatment resistance is a substantial challenge, often leading to relapse and distant metastasis. Tumor heterogeneity in HER2-positive breast cancer drives the evolution of resistant clones following therapeutic stress. However, the targetable drivers of anti-HER2 treatment resistance are not thoroughly identified. This study aims to use neoadjuvant-targeted therapy cohorts and a patient-derived organoid in vitro treatment model to uncover the potential targetable drivers of anti-HER2 treatment resistance. it is found that LINC01235 significantly enhances DNA replication licensing and chromosomal instability, fostering clonal expansion and evolution, and ultimately increasing resistance to therapeutic interventions. LINC01235 regulates global H3K27ac, H3K9ac, and H3K36me3 modifications, promotes H2A.Z expression in regulatory regions, and increases the accessibility of DNA licensing factors to their promoter regions. XRCC5 is identified as a key component for maintaining genomic stability, crucial for LINC01235's role in replication licensing. Furthermore, therapeutic strategies targeting LINC01235, including the use of antisense oligonucleotides or ATR inhibitors, which showed promise in overcoming treatment resistance are explored. These findings underscore the pivotal role of LINC01235 in driving resistance mechanisms and highlight novel avenues for targeted therapies to improve the outcomes of patients with HER2-positive breast cancer.

Artificial Intelligence and Breast Cancer Management: From Data to the Clinic

Breast cancer (BC) remains a significant threat to women's health worldwide. The oncology field had an exponential growth in the abundance of medical images, clinical information, and genomic data. With its continuous advancement and refinement, artificial intelligence (AI) has demonstrated exceptional capabilities in processing intricate multidimensional BC-related data. AI has proven advantageous in various facets of BC management, encompassing efficient screening and diagnosis, precise prognosis assessment, and personalized treatment planning. However, the implementation of AI into precision medicine and clinical practice presents ongoing challenges that necessitate enhanced regulation, transparency, fairness, and integration of multiple clinical pathways. In this review, we provide a comprehensive overview of the current research related to AI in BC, highlighting its extensive applications throughout the whole BC cycle management and its potential for innovative impact. Furthermore, this article emphasizes the significance of constructing patient-oriented AI algorithms. Additionally, we explore the opportunities and potential research directions within this burgeoning field.

Monoclonal Antibodies in Clinical Trials for Breast Cancer Treatment

One of the most potent therapeutic and diagnostic agents in contemporary medicine is the monoclonal antibody (mAb). mAbs can perform a variety of tasks in breast cancer (BC), including identifying and delivering therapeutic medications to targets, preventing cell development, and suppressing immune system inhibitors including directly attacking cancer cells. mAbs are one of the most effective therapeutic options, particularly for HER2, but they have not been well studied for their use in treating other forms of BC, particularly triple negative breast tumors. Bispecific and trispecific mAbs have created new opportunities for more targeted specific efficacy, which has a positive impact on the viability of antigen specificity. They are more versatile and effective than other forms of treatment, emerging as most popular option for treating BC. However, mAbs have a limit in treatment due to certain adverse effects, including fever, shaking, exhaustion, headache, nausea, and vomiting, as well as rashes, bleeding, and difficulty breathing. To examine the current and prospective future capacities of mAbs with regard to the detection and treatment of BC, the present review highlights advantages and disadvantages of mAb approach.

Proteogenomic discovery of RB1-defective phenocopy in cancer predicts disease outcome, response to treatment, and therapeutic targets

Genomic defects caused by truncating mutations or deletions in the Retinoblastoma tumor suppressor gene (RB1) are frequently observed in many cancer types leading to dysregulation of the RB pathway. Here, we propose an integrative proteogenomic approach that predicts cancers with dysregulation in the RB pathway. A subset of these cancers, which we term as "RBness," lack RB1 genomic defects and yet phenocopy the transcriptional profile of RB1-defective cancers. We report RBness as a pan-cancer phenomenon, associated with patient outcome and chemotherapy response in multiple cancer types, and predictive of CDK4/6 inhibitor response in estrogen-positive breast cancer. Using RNA interference and a CRISPR-Cas9 screen in isogenic models, we find that RBness cancers also phenocopy synthetic lethal vulnerabilities of cells with RB1 genomic defects. In summary, our findings suggest that dysregulation of the RB pathway in cancers lacking RB1 genomic defects provides a molecular rationale for how these cancers could be treated.

The multiple functions and mechanisms of long non-coding RNAs in regulating breast cancer progression

Breast cancer (BC) is a malignant tumor that has the highest morbidity and mortality rates in the female population, and its high tendency to metastasize is the main cause of poor clinical prognosis. Long non-coding RNAs (lncRNAs) have been extensively documented to exhibit aberrant expression in various cancers and influence tumor progression via multiple molecular pathways. These lncRNAs not only modulate numerous aspects of gene expression in cancer cells, such as transcription, translation, and post-translational modifications, but also play a crucial role in the reprogramming of energy metabolism by regulating metabolic regulators, which is particularly significant in advanced BC. This review examines the characteristics and mechanisms of lncRNAs in regulating BC cells, both intracellularly (e.g., cell cycle, autophagy) and extracellularly (e.g., tumor microenvironment). Furthermore, we explore the potential of specific lncRNAs and their regulatory factors as molecular markers and therapeutic targets. Lastly, we summarize the application of lncRNAs in the treatment of advanced BC, aiming to offer novel personalized therapeutic options for patients.

Exploring the anticancer potential of Jerantinine A from Tabernaemontana coronaria against prostate, breast, and ovarian cancers: a computational approach

OBJECTIVES

Cancer remains a significant global health challenge, with prostate, breast, and ovarian cancers ranking among the leading causes of morbidity and mortality. Natural products, particularly those derived from medicinal plants, have gained attention for their potential in alternative cancer therapies. The main objective of the study was an isolation and characterization of Jerantinine A, a bioactive alkaloid from Tabernaemontana coronaria, and its interactions with key protein targets involved in cancer progression.

METHODS

Jerantinine A was isolated through column chromatography and characterized using spectroscopic techniques, including UV-visible spectroscopy, FTIR, and NMR. Molecular docking studies were performed to assess its binding affinities with six critical protein targets: PTEN and androgen receptor for prostate cancer, CXCR4 and HER2 for ovarian cancer, and CDK1 and NEK2 for breast cancer.

RESULTS

Molecular docking analyses revealed that Jerantinine A exhibits strong binding affinities with all six protein targets, suggesting its potential to inhibit cancer cell proliferation by interfering with key signaling pathways.

CONCLUSIONS

These findings underscore the therapeutic potential of T. coronaria, particularly through Jerantinine A, as a promising candidate for cancer treatment. By targeting pivotal proteins associated with prostate, breast, and ovarian cancers, Jerantinine A offers a foundation for further research and development as a novel anti-cancer agent.

Molecular Subtypes and Mechanisms of Breast Cancer: Precision Medicine Approaches for Targeted Therapies

Breast cancer remains one of the most prevalent diseases worldwide, primarily affecting women. Its heterogeneous nature poses a significant challenge in the development of effective and targeted treatments. Molecular characterization has enabled breast cancer to be classified into four main subtypes: luminal A, luminal B, HER2-positive, and triple-negative breast cancer, based on hormone receptor expression and HER2 status. A deeper understanding of these molecular markers and their associated signaling pathways, such as MAPK and PI3K/AKT, is essential for improving prognosis and optimizing treatment strategies. Currently, several therapeutic agents are utilized in neoadjuvant and adjuvant therapies, often in combination with surgical interventions. However, emerging evidence highlights the growing challenge of drug resistance, which significantly limits the efficacy of existing treatments. Addressing this issue may require innovative approaches, including combination therapies and precision medicine strategies, tailored to the molecular profile of each patient. Therefore, a comprehensive understanding of the pathophysiologic mechanisms driving breast cancer progression and resistance is crucial for the development of advanced targeted therapies with greater precision and efficacy. This review aims to explore recent advancements in molecular research related to breast cancer subtypes and provide a critical analysis of current therapeutic approaches within the framework of precision medicine.

Comprehensive analysis of HER2 Low Breast Cancer Response to Neoadjuvant Chemotherapy, a Retrospective Cohort Study

BACKGROUND

This study aimed to identify the response and survival outcomes of HER2-low patients following neoadjuvant chemotherapy (NAC).

METHOD

A retrospective cohort of patients who received NAC in the Department of Breast Surgery at Peking Union Medical College Hospital (PUMCH) from September 27, 2016, to January 23, 2024, was reviewed. Multivariate logistic regression and Cox proportional hazards models were used to identify factors associated with pathological complete response (pCR) and survival outcomes. The Kaplan-Meier method was applied to compare survival outcomes between HER2-zero and HER2-low patients.

RESULT

Four hundred and twenty-one patients meeting the inclusion criteria. The pCR rate of HER2-zero patients was significantly higher than that of HER2-low patients after adjusting for confounders (OR = 2.83, 95% CI: 1.44-5.65, adjusted P = .003). HER2-low patients demonstrated the most stable status after NAC within the hormone receptor (HR)-positive subset (80.82%) and the most unstable status within the HR-negative subset (57.69%). HER2-zero status was associated with worse disease-free survival (DFS) (HR = 1.94, 95% CI: 1.13-3.32, adjusted P = .02), but not with overall survival (OS) (HR = 1.18, 95% CI: 0.59-2.37, P = .65). HER2-zero patients had significantly worse DFS than HER2-low patients in the entire cohort (P = .014) and the HR-positive subset (P < .001). pCR could serve as a surrogate endpoint of favorable survival outcomes for HER2-zero patients, but not for HER2-low patients.

CONCLUSION

HER2-low patients might exhibit distinct characteristics compared with HER2-zero patients following NAC. Further multicenter, prospective studies are warranted to validate the conclusions of this exploratory research and assess whether HER2-low expression could serve as a new clinical subtype for evaluating NAC treatment outcomes.

Construction and validation of a novel nomogram for prediction of lymph node metastasis in HER2-positive breast cancer: based on the optimal number of examined lymph nodes for accurate nodal staging

PURPOSE

This study aimed to construct and validate a novel nomogram for prediction of lymph node metastasis in HER2-positive breast cancer based on the optimal number of examined lymph nodes (ELNs) for accurate nodal staging.

METHODS

We included 4,040 patients diagnosed with HER2-positive breast cancer from the SEER database, randomly allocating them into training and validation cohorts in a 7:3 ratio. The optimal number of ELNs was identified via piecewise linear regression. The association of ELNs count with nodal migration was evaluated through Logistic Regression (LR) analysis and Random Forest (RF). The nomogram was constructed, and its' performance was evaluated by the receiver operating characteristic curves, calibration curve and Decision curve analysis curves.

RESULTS

The optimal number of ELNs was 13. LR and RF identified the optimal number of ELNs, radiotherapy status, chemotherapy status, T stage, and grade as independent predictive variables for node metastasis, which were used in the nomogram's construction. And the area under the curve values for the nomogram were 0.829 (95% confidence interval (CI): 0.813-0.845) and 0.833 (95% CI:0.808-0.858) in the training and test split respectively, surpassing those of the optimal number of ELNs (0.649, 95% CI: 0.631-0.667 and 0.676, 95% CI:0.648-0.704). Calibration plots exhibited low Brier scores (0.150 for training split, 0.145 for test split).

CONCLUSION

This study developed a novel nomogram that integrates the optimal number of ELNs with other independent risk factors, facilitating individualized prediction of lymph node metastasis in patients with HER2-positive breast cancer.

Complete preclinical evaluation of the novel antibody mimetic Nanofitin-IRDye800CW for diverse non-invasive diagnostic applications in the management of HER-2 positive tumors

There are well-known limitations associated to the use of antibodies in the non-invasive detection of HER-2 expression. In fact, current procedures recommended for diagnostic purposes of HER-2 status are still invasive techniques. Here, a novel, smaller diagnostic probe, the anti-HER-2 Nanofitin conjugated to the fluorophore IRDye800CW (NF-800), underwent an in vitro/in vivo proof of concept study by Optical Imaging. NF-800 showed high affinity and specificity for the cellular target, and the ability to internalize into HER-2 positive cells. By ex vivo analysis, NF-800 showed a selective tumor accumulation in xenograft tumor models, and also a good tumor targeting efficacy in translational preclinical setups, such as orthotopic and patient-derived xenograft (PDX) models. In the latter, NF-800 was compared to the anti-HER-2 antibody Trastuzumab, displaying a large diagnostic advantage. Interestingly, NF-800 did not seem to share the same binding site with Trastuzumab and Pertuzumab, opening specific theragnostic opportunities for NF-800 in combination with standard-of-care antibodies.