Characterisation of luminal and triple-negative breast cancer with HER2 Low protein expression

The impact of HER2-Low expression in salivary duct carcinoma: Clinicopathologic features, survival outcomes, and association with androgen receptor-targeted therapy

OBJECTIVES

Recent advances in systemic therapy for salivary duct carcinoma (SDC) have been driven by the development of HER2- and androgen receptor (AR)-targeted therapies. Trastuzumab deruxtecan has proven effective not only in HER2-positive but also HER2-low breast and gastro-esophageal cancers. However, the significance of HER2-low expression in SDC remains unknown. This study aimed to investigate the clinicopathologic characteristics, prognostic implications, and impact on efficacy to AR-targeted therapy in HER2-low SDC.

MATERIALS AND METHODS

This was a multi-center, observational study. HER2 status was reclassified as follows: HER2-positive (IHC3+ or 2+/ISH+ ), HER2-low (IHC1+ or 2+/ISH-), and HER2-zero (IHC0). The subjects were compared in three groups: total population, curative treatment cohort, and AR-targeted therapy cohort.

RESULTS

The total population consisted of 526 patients, of whom, 271 (52 %), 184 (35 %), and 71 (13 %) had HER2-positive, -low, and -zero tumors, respectively. Sex, M category, histological origin, Ki67, and p53 expression differed significantly between the HER2-low and HER2-positive cases. No differences in relapse-free or overall survival were observed for HER2 status in the curative treatment cohort; however, in the AR-targeted therapy cohort, the HER2-low group had significantly better response rates (41.6 % vs. 18.9 %, Odds ratio = 0.30, P = 0.012) and longer median progression-free survival (6.9 vs. 4.2 months, Hazard ratio = 1.61, P = 0.029) than those of the HER2-positive group.

CONCLUSION

HER2-low showed different clinicopathologic features from HER2-positive cases, with no prognostic differences observed in patients who underwent curative treatment. Still, HER2-low may be associated with the efficacy of AR-targeted therapy.

Landscape of lncRNAs expressed in Mexican patients with triple‑negative breast cancer

Long non‑coding RNAs (lncRNAs) are key regulators of gene expression, that can regulate a range of carcinogenic processes. Moreover, they exhibit stability in biological fluids, with some displaying tissue specificity. As their expression depends on specific conditions or is linked to the regulation of particular signaling pathways, lncRNAs are promising candidates for providing insights into the likely progression of the disease. This allows for the stratification of patients based on their risk of progression, making them potential prognostic biomarkers in various types of cancer. In addition, the tissue‑specific expression profile of lncRNAs renders them ideal candidates for detection, prognosis and monitoring of cancer progression. The present study aims to provide an overview of differentially expressed lncRNAs in Mexican patients with triple‑negative breast cancer (TNBC), a subtype of breast cancer. The aim was to identify potential prognostic biomarkers that can be applied to improve the clinical management of Mexican patients with TNBC. Human Transcriptome Array 2.0 microarrays were used to analyze the transcriptome of TNBC and luminal tumors, which are reported to have a good prognosis amongst aggressive tumor types. Subsequently, results from these microarrays were validated in a cohort from The Cancer Genome Atlas, an independent cohort of Mexican patients and in breast cancer cell lines (MCF7, ZR75, T47D, MDA‑MB‑231, MDA‑MB‑468 and BT20). A total of 746 differentially expressed transcripts were identified, including 102 lncRNAs in TNBC compared with luminal tumors. Among the lncRNAs with the most significant changes in expression levels, SOX9‑AS was highly expressed in TNBC, whereas the expression of Lnc‑peroxidasin‑3:1 (Lnc‑PXDN‑3:1), Lnc‑RNA Synapse Defective Rho GTPase Homolog (Lnc‑SYDE) and long intergenic non‑coding RNA (LINC)01087 were decreased. In addition, the low expression of lncRNA LINC01087, LINC02568, ACO22196, and lncRNA eosinophil granule ontogeny transcript (Lnc‑EGOT) was associated with poor overall survival (OS). Further analysis revealed that the high expression levels of Lnc‑PXDN‑3:1, Lnc RNA fibrous sheath interacting protein 1‑6:3 and (LINC)00182 were associated with reduced survival in patients with the luminal subtype of breast cancer. Similarly, low expression levels of lncRNAs such as GATA binding protein 3‑1 (Lnc‑GATA‑3‑1), LINC01087, and BX679671.1 in luminal subtypes of breast cancer, as well as LINC00504 and LncRNA rho guanine nucleotide exchange factor 38 intronic transcript 1 (Lnc‑ARHGEF38‑IT1) in basal subtypes have been linked to poorer survival. The interactions and functions of LINC01087 were then investigated, revealing the interaction of LINC01087 with RNAs and transcription factors, highlighting their potential involvement in the estrogen receptor pathway. The present study provided a detailed analysis of the expression of lncRNAs in TNBC, which highlights the role of lncRNAs as a biomarker in the survival outcomes of patients with breast cancer to improve the understanding of transcriptional regulation in TNBC.

Molecular and clinicopathological characteristics of invasive breast cancers with HER2-ultralow expression

The identification of HER2-low and HER2-ultralow breast cancer (BC) subgroups has garnered considerable attention following the demonstrated clinical efficacy of HER2-targeted antibody-drug conjugates (ADCs). This study investigated whether these subgroups represent distinct biological subtypes compared to HER2-undetected tumors. Analyzing 297 HER2-negative BCs stratified by immunohistochemistry (50.2 % HER2-low, 35.7 % HER2-ultralow, 14.1 % HER2-undetected), we systematically compared clinicopathological and molecular profiles (AmoyDx® HANDLE Classic Panel). HER2-detected tumors (combined low/ultralow cohort) showed significant differences in hormone receptor (HR) positivity versus HER2-undetected tumors (p = 0.001). The mutation frequencies of the three most frequently altered genes (TP53, PIK3CA, and PTEN) in HER2-ultralow tumors did not significantly differ from those in the two other subgroups. However, HER2-detected tumors exhibited different molecular alterations compared to HER2-undetected tumors, with increased PIK3CA mutations in the former (p = 0.024) and TP53 mutation enrichment in the latter (p = 0.007). These differences attenuated when tumors were stratified by HR status. In addition, HER2 expression positively correlated with ERBB2 copy number, showing higher mean values in HER2-detected subgroups versus undetected counterparts (2.01 ± 0.31 vs 1.88 ± 0.23; p = 0.011). While no significant survival differences emerged across subgroups, most mortality events occurred in HER2-low (6/12, 50.0 %) and HER2-ultralow (5/12, 41.7 %) cases. Our findings indicate that while HER2-low and HER2-ultralow breast cancers may not represent independent biological subtypes, their clinical distinction from HER2-undetected tumors remains crucial due to potential ADC therapeutic implications.

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.

Triple-negative breast cancer molecular subtypes and potential detection targets for biological therapy indications

Triple-negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer associated with poor prognosis. While chemotherapy remains the conventional treatment approach, its efficacy is limited and often accompanied by significant toxicity. Advances in precision-targeted therapies have expanded treatment options for TNBC, including immunotherapy, poly (ADP-ribose) polymerase inhibitors, androgen receptor inhibitors, cell cycle-dependent kinase inhibitors, and signaling pathway inhibitors. However, the heterogeneous nature of TNBC contributes to variations in treatment outcomes, underscoring the importance of identifying intrinsic molecular subtypes for personalized therapy. Additionally, due to patient-specific variability, the therapeutic response to targeted treatments is inconsistent. This highlights the need to strategize patients based on potential therapeutic targets for targeted drugs to optimize treatment strategies. This review summarizes the classification strategies and immunohistochemical (IHC) biomarkers for TNBC subtypes, along with potential targets for identifying indications for targeted drug therapy. These insights aim to support the development of personalized treatment approaches for TNBC patients.

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.

Clinical characteristics, metastasis patterns, and treatment outcomes of HER2-low breast cancer

Breast cancer (BC) is a heterogeneous disease, traditionally classified by hormone receptor and HER2 (human epidermal growth factor receptor 2) status. HER2-low, characterized by low HER2 expression without gene amplification, recently gained attention. While new therapies are promising, its clinical significance remains unclear. We analysed 241,510 BC patients diagnosed between 2000 and 2020 in Germany using data from the German Cancer Registry Group. HER2 status was determined using immunohistochemistry and fluorescence in situ hybridization results, and patients were classified as HER2-positive, HER2-low or HER2-zero. Clinical features, chemosensitivity and long-term outcomes - metastasis-free survival (MFS), recurrence-free survival (RFS), and overall survival (OS) - were analysed using Cox models. HER2-low comprised 42% of female and 47% of male patients, predominantly hormone receptor positive. Metastatic patterns in HER2-low and HER2-zero were similar but differed from HER2-positive, which showed more liver metastasis and multiple metastatic sites. HER2-positive showed worse MFS, RFS, and OS than HER2-zero and HER2-low subtypes. Pathological complete response (pCR) rates after neoadjuvant chemotherapy were highest in HER2-positive. HER2-low has higher hormone receptor positivity, distinguishing it from HER2-zero. While metastatic behaviour, treatment and long-term response in HER2-low were comparable to HER2-zero, the hormone receptor status seems to play a critical role in these outcomes.

Genomic landscape of circulating tumor DNA in HER2-low metastatic breast cancer

The large population of HER2-low breast cancer patients necessitates further research to provide enhanced clinical guidance. In this study, we retrospectively analyzed 1071 metastatic breast cancer (MBC) patients and the circulating tumor DNA (ctDNA) to investigate clinicopathological and genetic alterations of HER2-low MBC patients. The effect of HER2-low status on different treatment modalities was explored in two prospective clinical trials (NCT03412383, NCT01917279) and a retrospective study. Our findings suggest TP53, PIK3CA, and ESR1 are frequently mutated genes in HER2-low MBC. Compared to the HER2-0 group, mutations observed in the HER2-low group are more closely associated with metabolic pathway alterations. Additionally, among patients with ERBB2 mutations and treated with pyrotinib, the HER2-low group may experience superior prognosis when compared to the HER2-0 group. Notably, we did not find any statistically significant disparity in the response to chemotherapy, endocrine therapy, or CDK4/6 inhibitor therapy between HER2-0 and HER2-low breast cancer patients. Interestingly, within the subgroup of individuals with metabolic pathway-related gene mutations, we found that HER2-low group exhibited a more favorable response to these treatments compared to HER2-0 group. Additionally, dynamic analysis showed the HER2-low MBC patients whose molecular tumor burden index decreased or achieved early clearance of ctDNA after the initial two treatment cycles, exhibited prolonged survival. Moreover, we classified HER2-low MBC into three clusters, providing a reference for subsequent treatment with enhanced precision. Our study offers valuable insights into the biology of HER2-low MBC and may provide reference for personalized treatment strategies.

Real-world application of disitamab vedotin (RC48-ADC) in patients with breast cancer with different HER2 expression levels: efficacy and safety analysis

BACKGROUND

Disitamab vedotin (RC48-ADC), an antibody-drug conjugate (ADC), combines specific antibody disitamab with cytotoxicity monomethyl auristatin E to effectively target the human epidermal growth factor receptor 2 (HER2) protein on tumor cells for precise elimination. Recent studies have demonstrated that RC48-ADC offers therapeutic benefits for patients with HER2-positive and HER2-low-expression breast cancer (BC). However, a thorough exploration of its efficacy and safety in real-world settings for patients with metastatic breast cancer (mBC) is currently lacking.

METHODS

This retrospective, multicenter, real-world study included patients with mBC who received RC48-ADC from September 2021 to March 2024. These patients include HER2-positive BC and HER2-low-expression BC. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), restricted mean survival time, objective response rate (ORR), and disease control rate (DCR). Factors affecting efficacy and the occurrence of treatment-related adverse events (TRAE) were evaluated.

RESULTS

The study included a cohort of 89 patients with mBC, with 48 of those being identified as HER2-positive. As of March 2024, 22 deaths were recorded, with an immature median OS. Total PFS varied from 1.0 to 31.2 months, with a median of 5.5 months (95% CI, 4.368-6.632). HER2-positive patients exhibited prolonged PFS compared with HER2-low-expression patients (6.6 months vs 4.1 months, P = .023). The overall ORR stood at 25.8% (95% CI, 0.178-0.358), with higher rates observed in HER2-positive patients compared with HER2-low-expression patients (31.3% vs 19.5%). Similarly, the overall DCR was 78.7% (95% CI, 0.691-0.859), with HER2-positive patients demonstrating superior DCR compared with HER2-low-expression patients (83.3% vs 73.2%). Notably, HER2 expression emerged as the primary determinant of RC48-ADC efficacy. The most prevalent TRAE among all patients included leukopenia (21.3%) and alopecia (20.2%).

CONCLUSION

RC48-ADC showcases promising efficacy and manageable safety in patients with both HER2-positive and HER2-low-expression mBC.

Possibility of Human Epidermal Growth Factor Receptor 2 Expression as a Treatment Selection Indicator in Early Triple-Negative Breast Cancer

Background This study aimed to evaluate the relationship among human epidermal growth factor receptor 2 (HER2) expression level, pathological complete response (pCR) rate of neoadjuvant chemotherapy, and prognosis in early-stage triple-negative breast cancer (TNBC). Methodology This retrospective study analyzed the relationship among HER2 expression level, pCR rate, clinicopathological factors, and prognosis in 39 patients who were diagnosed with TNBC between 2012 and 2020 at Osaka Rosai Hospital and underwent surgery after neoadjuvant chemotherapy (NAC). Results Patients' age ranged 33-86 (median = 57) years, and the observation period ranged 5-130 (median = 60) months. The HER2 expression levels were HER2 (0), HER2 (1+), and HER2 (2+, fluorescence in situ hybridization test (FISH); negative) for 18, 12, and 9 cases, respectively. The pCR rates were 38.9%, 8.3%, and 44.4% for HER2 (0), HER2 (1+), and HER2 (2+, FISH; negative), respectively, and no correlation was observed with the degree of HER2 expression. The prognosis of distant disease-free survival (DDFS) differed depending on the HER2 status (p = 0.032), and this trend was also observed in overall survival (OS) (p = 0.012). This tendency became even stronger when comparing HER2-low and HER2 (0) (p = 0.028 and p = 0.01, respectively). HER2 expression was significantly decreased from before to after NAC (p = 0.001). Conclusions HER2 expression did not correlate with the pCR rate of NAC but did correlate with DDFS and OS. Thus, patients with an HER2 (0) status are considered to have a poor prognosis and should be more aggressively considered for perioperative chemotherapy, e.g., immune checkpoint inhibitors.

In silico evaluation of potential breast cancer receptor antagonists from GC-MS and HPLC identified compounds in Pleurotus ostreatus extracts

Introduction: Pharmacotherapeutic targets for breast cancer include the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor (EGFR). Inhibitors of these receptors could be interesting therapeutic candidates for the treatment and management of breast cancer (BC). Aim: This study used GC-MS and HPLC to identify bioactive compounds in Pleurotus ostreatus (P. ostreatus) extracts and applied in silico methods to identify potent EGFR, ER, and PR inhibitors from the compounds as potential drug candidates. Method: GC-MS and HPLC were used to identify bioactive chemicals in P. ostreatus extracts of aqueous (PO-A), methanol (PO-M), ethanol (PO-E), chloroform (PO-C), and n-hexane (PO-H). The ER, PR, and EGFR model optimization and molecular docking of compounds/control inhibitors in the binding pocket were simulated using AutoDock Vina in PyRx. The drug-likeness, pharmacokinetic, and pharmacodynamic features of prospective docking leads were all anticipated. Result: The results indicated the existence of 29 compounds in PO-A, 36 compounds in PO-M and PO-E, 42 compounds in PO-C, and 22 compounds in PO-H extracts. With ER, only o-tolylamino-acetic acid (4-nitro-benzylidene)-hydrazide (-7.5 kcal mol-1) from the ethanolic extract could bind to the receptor. PR and EGFR, on the other hand, identified several compounds with higher binding affinities than the control. Ergotaman-3',6',18-trione (-8.1 kcal mol-1), 5,10-diethoxy-2,3,7,8-tetrahydro-1H,6H-dipyrrolo[1,2-a:1',2'-d]pyrazine (-7.8 kcal mol-1) from the aqueous extract; o-tolylamino-acetic acid (4-nitro-benzylidene)-hydrazide (-8.4 kcal mol-1) from the ethanolic extract had better binding affinity compared to progesterone (-7.7 kcal mol-1). Likewise, ergotaman-3',6',18-trione (-9.7 kcal mol-1) from the aqueous extract and phenol, 2,4-bis(1,1-dimethyl ethyl) (-8.2 kcal mol-1) from the chloroform extract had better binding affinities compared to the control, gefitinib (-7.9 kcal mol-1) with regards to EGFR. None of the PO-H or PO-M extracts outperformed the control for any of the proteins. Phenols and flavonoids such as quercetin, luteolin, rutin, chrysin, apigenin, ellagic acid, and naringenin had better binding affinity to PR and EGFR compared to their control. Conclusion: The identified compounds in the class of phenols and flavonoids were better lead molecules due to their ability to strongly bind to the proteins' receptors. These compounds showed promising drug-like properties; they could be safe and new leads for creating anticancer medicines.

Breast cancer highlights from 2023: Knowledge to guide practice and future research

This narrative work highlights a selection of published work from 2023 with potential implications for breast cancer practice. We feature publications that have provided new knowledge immediately relevant to patient care or for future research. We also highlight guidelines that have reported evidence-based or consensus recommendations to support practice and evaluation in breast cancer diagnosis and treatment. The scope of selected highlights represents various domains and disciplines in cancer control, from prevention to treatment of early and advanced breast cancer.