Emerging treatments in HER2-positive advanced breast cancer: Keep raising the bar

Personalized prediction of breast cancer candidates for Anti-HER2 therapy using 18F-FDG PET/CT parameters and machine learning: a dual-center study

Background

Accurately evaluating human epidermal growth factor receptor (HER2) expression status in breast cancer enables clinicians to develop individualized treatment plans and improve patient prognosis. The purpose of this study was to assess the performance of a machine learning (ML) model that was developed using 18F-FDG PET/CT parameters and clinicopathological features in distinguishing different levels of HER2 expression in breast cancer.

Methods

This retrospective study enrolled breast cancer patients who underwent 18F-FDG PET/CT scans prior to treatment at Lianyungang First People's Hospital (centre 1, n=157) and the Third Affiliated Hospital of Soochow University (centre 2, n=84). Two classification tasks were analysed: distinguishing HER2-zero expression from HER2-low/positive expression (Task 1) and distinguishing HER2-low expression from HER2-positive expression (Task 2). For each task, patients from Centre 1 were randomly divided into training and internal test sets at a 7:3 ratio, whereas patients from Centre 2 served as an external test set. The prediction models included logistic regression (LR), support vector machine (SVM), extreme gradient boosting (XGBoost) and multilayer perceptron (MLP), and SHAP analysis provided model interpretability. Model performance was evaluated via the area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).

Results

XGBoost models exhibited the best predictive performance in both tasks. For Task 1, recursive feature elimination (RFE) was used to select 8 features, excluding pathological features, and the XGBoost model achieved AUCs of 0.888, 0.844 and 0.759 for the training, internal and external testing sets, respectively. The top three features according to the SHAP values were the tumour minimum diameter, mean standardized uptake value (SUVmean) and CTmean. For Task 2, 9 features were selected, including progesterone receptor (PR) status as a pathological feature. The XGBoost model achieved AUCs of 0.920, 0.814 and 0.693 for the training, internal and external testing sets, respectively. The top three features according to the SHAP values were the PR status, maximum tumour diameter and metabolic tumour volume (MTV).

Conclusions

ML models that incorporate 18F-FDG PET/CT parameters and clinicopathological features can aid in the prediction of different HER2 expression statuses in breast cancer.

Leveraging HER2-targeted biparatopic antibodies in solid tumors

Biparatopic antibodies (bpAbs), which target non-overlapping epitopes on the same antigen, offer unique mechanisms of action and therapeutic applications that surpass those of conventional monospecific antibodies. These distinctive properties have positioned bpAbs as effective therapeutic agents in the treatment of cancer and infectious diseases, especially in cases where current treatments face limitations. Among these, HER2-targeted bpAbs have shown significant improvements in survival outcomes for patients with solid tumors that depend on HER2 signaling. However, a comprehensive understanding of their clinical impact, mechanisms of action, and limitations in therapeutic use remains lacking. Here, we review and contrast the clinical performance of the well-established HER2-targeted bpAbs in current use, with a focus on their mechanisms of action, associated limitations, and potential combination strategies. We also highlight emerging investigational bpAbs-based agents that have shown promise in the treatment of HER2-positive solid cancers. These advancements may lead to enhanced therapeutic options and potentially broaden the scope of bpAbs in cancer therapy.

Unravelling the role of ubiquitin-specific proteases in breast carcinoma: insights into tumour progression and immune microenvironment modulation

Breast cancer is a prevalent malignancy worldwide, and its treatment has increasingly shifted towards precision medicine, with immunotherapy emerging as a key therapeutic strategy. Deubiquitination, an essential epigenetic modification, is regulated by deubiquitinating enzymes (DUBs) and plays a critical role in immune function and tumor progression. Ubiquitin-specific proteases (USPs), a prominent subgroup of DUBs, are involved in regulating immune cell functions, antigen processing, and T cell development in the context of breast cancer. Certain USPs also modulate the differentiation of immune cells, such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), within the breast cancer immune microenvironment. Furthermore, several USPs influence the expression of PD-L1, thus affecting the efficacy of immune checkpoint inhibitors. The overexpression of USPs may promote immune evasion, contributing to the development of treatment resistance. This review elucidates the role of USPs in modulating the immune microenvironment and immune responses in breast cancer. Additionally, it discusses effective strategies for combining USP inhibitors with other therapeutic agents to enhance treatment outcomes. Therefore, targeting USPs presents the potential to enhance the efficacy of immunotherapy and overcome drug resistance, offering a more effective treatment strategy for breast cancer patients.

Modeling the management of patients with human epidermal growth factor receptor 2-positive breast cancer with liquid biopsy: the future of precision medicine

PURPOSE OF REVIEW

In the evolving landscape of human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) management, liquid biopsy offers unprecedented opportunities for guiding clinical decisions. Here, we review the most recent findings on liquid biopsy applications in HER2-positive BC and its potential role in addressing challenges specific to this BC subtype.

RECENT FINDINGS

Recent studies have highlighted the significance of liquid biopsy analytes, primarily circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs), in stratifying patients' prognosis, predicting treatment response, and monitoring tumor evolution in both early and advanced stages of BC. Liquid biopsy holds promise in studying minimal residual disease to detect and potentially treat disease recurrence before it manifests clinically. Additionally, liquid biopsy may have significant implication in the management of brain metastasis, a major challenge in HER2-positive BC, and could redefine parameters for determining HER2 positivity. Combining ctDNA and CTCs is crucial for a comprehensive understanding of HER2-positive tumors, as they provide complementary insights.

SUMMARY

Research efforts are needed to address analytical challenges, validate, and broaden the application of liquid biopsy in HER2-positive BC. This effort will ultimately facilitate its integration into clinical practice, optimizing the care of patients with HER2-positive tumors.

HER-2 Receptor and αvβ3 Integrin Dual-Ligand Surface-Functionalized Liposome for Metastatic Breast Cancer Therapy

Human epidermal growth factor receptor-2 (HER2)-positive breast cancer metastasis remains the primary cause of mortality among women globally. Targeted therapies have revolutionized treatment efficacy, with Trastuzumab (Trast), a monoclonal antibody, targeting HER2-positive advanced breast cancer. The tumor-homing peptide iRGD enhances the intratumoral accumulation and penetration of therapeutic agents. Liposomes serve as versatile nanocarriers for both hydrophilic and hydrophobic drugs. Gefitinib (GFB) is a potential anticancer drug against HER2-positive breast cancer, while Lycorine hydrochloride (LCH) is a natural compound with anticancer and anti-inflammatory properties. This study developed TPGS-COOH-coated liposomes co-loaded with GFB and LCH, prepared by the solvent injection method, and surface-functionalized with Trast and iRGD. The dual surface-decorated liposomes (DSDLs) were characterized for their particle size (PS), polydispersity index (PDI), zeta potential (ZP), surface chemistry, surface morphology, and their crystallinity during in-vitro drug release, drug encapsulation, and in-vitro cell line studies on SK-BR-3 and MDA-MB-231 breast cancer cells. The half-maximum inhibitory concentration (IC-50) values of single decorated liposomes (SDLs), iRGD-LP, and Trast-LP, as well as DSDLs (iRGD-Trast-LP) on SK-BR-3 cells, were 6.10 ± 0.42, 4.98 ± 0.36, and 4.34 ± 0.32 μg/mL, respectively. Moreover, the IC-50 values of SDLs and DSDLs on MDA-MB-231 cells were 15.12 ± 0.68, 13.09 ± 0.59, and 11.08 ± 0.48 μg/mL, respectively. Cellular uptake studies using confocal laser scanning microscopy (CLSM) showed that iRGD and Trast functionalization significantly enhanced cellular uptake in both cell lines. The wound-healing assay demonstrated a significant reduction in SDL and DSDL-treated MDA-MB-231 cell migration compared to the control. Additionally, the blood compatibility study showed minimal hemolysis (less than 5% RBC lysis), indicating good biocompatibility and biosafety. Overall, these findings suggest that TPGS-COOH-coated, GFB and LCH co-loaded, dual-ligand (iRGD and Trast) functionalized, multifunctional liposomes could be a promising therapeutic strategy for treating HER2-positive metastatic breast cancer.