Hormone Receptor/Human Epidermal Growth Factor Receptor 2-positive breast cancer: Where we are now and where we are going

Paclitaxel-related type I Kounis Syndrome in a very young patient with HER2-positive breast cancer and the role of genomics to disentangle a complex therapeutic scenario: a case report and narrative review

We present the first documented oncologic case of a type I Kounis syndrome (KS) following paclitaxel administration, in a very young patient with HER2-positive(+) early-stage breast cancer (BC). KS is a relatively rare acute coronary syndrome triggered by anaphylactic or hypersensitivity reactions, of which there is limited awareness among healthcare providers. It is subdivided in four subtypes depending on cardiac artery medical history. While no established management guidelines exist, its treatment requires addressing severe infusion reactions while ensuring proper myocardial perfusion. We hereby illustrate its successful acute management and report on how tumor genomics through the novel HER2DX assay helped re-defining the entire neo/adjuvant oncologic strategy. HER2DX integrates tumor size and nodal involvement with 27 genes' expression data tracking four biological BC-related and immunologic signatures so to estimate a prognostic and a predictive score. This report demonstrates how clinical and genomic data can be effectively integrated to optimize therapeutic decisions in HER2+ BC, offering a model for personalized care also in atypical and complex cases.

Multidisciplinary discussion on phenotypical characterization of metastatic breast cancer and patient pathway optimization from an expert panel across South Italian regions

Breast cancer (BC) might change its receptor status during malignant progression, resulting in challenging clinical care. The project, developed during two residential meetings by expert Italian oncologists and pathologists, was aimed at optimizing metastatic BC management. A 17-point survey was administered to healthcare workers in centers of three regions, essentially to assess the perception of metastasis biopsy on treatment choice in different BC molecular subtypes, the appropriate timing for performing tissue and liquid biopsy in metastatic BC, the selection of target genes and the use of multidisciplinary approaches in tumour management. Nineteen centers participated in the survey. The first important finding was that most centers manage more than 150 patients yearly, and 95% have a pathology department. Some questions received a substantial agreement: tissue biopsy of metastatic BC was largely considered as mandatory, generally performed at onset of metastatic disease. Liquid biopsy is not used by all centers, confirming its strict dependency on the available technologies. The answers on the therapeutic line change in case of HER2 + disease becoming triple negative confirmed an attitude consistent with clinical practice. The survey also revealed that half of the interviewed oncologists discuss with multidisciplinary team only for selected cases. The survey revealed that while a shared consensus exists on the importance of metastasis biopsy, some areas still deserve attention to achieve standardized approaches: interdisciplinary collaboration and more effective communication between specialists and patients are necessary to optimize the diagnostic and therapeutic journey of women with metastatic BC.

Molecular classification of hormone receptor-positive /HER2-positive breast cancer reveals potential neoadjuvant therapeutic strategies

Significant heterogeneity exists in hormone receptor (HR)-positive/HER2-positive (HR+/HER2+) breast cancer, contributing to suboptimal pathological complete response rates with conventional neoadjuvant treatment regimens. Overcoming this challenge requires precise molecular classification, which is pivotal for the development of targeted therapies. We conducted molecular typing on a cohort of 211 patients with HR+/HER2+ breast cancer and performed a comprehensive analysis of the efficacy of various neoadjuvant treatment regimens. Our findings revealed four distinct molecular subtypes, each exhibiting unique characteristics and therapeutic implications. The HER2-enriched subtype, marked by activation of the HER2 signaling and hypoxia-inducible factor 1 (HIF-1) pathway, may benefit from intensified anti-HER2-targeted therapy. Estrogen receptor (ER)-activated subtype demonstrated potential sensitivity to combined therapeutic strategies targeting both ER and HER2 pathways. Characterized by high immune cell infiltration, the immunomodulatory subtype showed sensitivity to HER2-targeted antibody-drug conjugates (ADCs) and promise for immune checkpoint therapy. The highly heterogeneous subtype requires a multifaceted therapeutic approach. Organoid susceptibility assays suggested phosphoinositide 3-kinase inhibitors may be a potential treatment option. These findings underscore the importance of molecular subtyping in HR+/HER2+ breast cancer, offering a framework for developing precise and personalized treatment strategies. By addressing the heterogeneity of the disease, these approaches have the potential to optimize therapeutic outcomes and improve patient care.

CYP2D6 polymorphisms and endoxifen concentration in Chinese patients with breast cancer

BACKGROUND

The plasma concentration of endoxifen, the active metabolite of tamoxifen, might be affected by different CYP2D6 genotypes in patients with breast cancer, but solid evidence is still lacking in Asian patients. This prospective study aimed to investigate the relationship between CYP2D6 genetic polymorphisms and endoxifen plasma concentrations among Chinese patients with breast cancer treated with tamoxifen.

METHODS

From August 2015 to June 2018, 110 patients with breast cancer were enrolled. CYP2D6 variant alleles and endoxifen plasma concentration were determined using Sanger sequencing and high-performance liquid chromatography-tandem mass spectrometry, respectively.

RESULTS

The most frequent allele of CYP2D6 was *10 (56.4%). The most frequent genotype of CYP2D6 was *10/*10 (33%), *1/*10(28.2%) and *2/*10(14.5%). Sixty-four patients (58.2%) were Normal Metabolizers (NM), while 46 (41.8%) were Intermediate Metabolizers (IM). All patients except two had endoxifen concentrations above the threshold of 5.9ng/ml. The median endoxifen plasma concentrations for patients with CYP2D6 genotypes *1/*2 and *1/10 were higher compared to other genotypes (p = 0.012). The median endoxifen plasma concentration was higher in NM than in IM (18ng/ml vs. 13ng/ml, p = 0.0077). Patients with CYP2D6*10(T/T) had lower endoxifen concentrations than those with *10(C/T) and *10(C/C) but the difference was not significant. There were no significant differences in adverse events between patients in the NM and IM groups or between patients with the CYP2D6*10 (T/T) genotype and non-*10 (T/T) genotype.

CONCLUSION

Only CYP2D6 IMs and NMs were identified in this study. Almost all patients had the endoxifen concentrations above the threshold. The endoxifen plasma concentration was lower in CYP2D6 IMs than in NMs, but these variants did not compromise the adverse effects of tamoxifen in Asian patients with breast cancer.

TRIAL REGISTRATION

The study protocol was approved by the institutional review boards of Sun YatSen University Cancer Center (Ethics approval number, B201506501,20160115).

Triple-positive breast cancer: navigating heterogeneity and advancing multimodal therapies for improving patient outcomes

Triple-positive breast cancer (TPBC), a unique subtype of luminal breast cancer, is characterized by concurrent positivity for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Owing to the crosstalk between the ER and HER2 signaling pathways, the standard of care and drug resistance of this particular subtype are difficult challenges. Recent research and clinical trials have indicated a shift in the treatment paradigm for TPBC from single-target therapies to multi-pathway, multitarget strategies aiming to comprehensively modulate intricate signaling networks, thereby overcoming resistance and enhancing therapeutic outcomes. Among multiple strategies, triple-drug therapy has emerged as a promising treatment modality, demonstrating potential efficacy in patients with TPBC. Moving forward, there is a critical need to perform in-depth analyses of specific mechanisms of cancer pathogenesis and metastasis, decipher the complex interactions between different genes or proteins, and identify concrete molecular targets, thus paving the way for the development of tailored therapeutic strategies to combat TPBC effectively.

Valuable predictive power of prognostic nutritional index in metastatic breast cancer patients treated with CDK4/6 inhibitors

AIMS AND OBJECTIVES

The prognostic value of nutritional status in HR+/HER2- metastatic breast cancer (mBC) patients treated with CDK4/6 inhibitors (CDK4/6is) and endocrine therapy (ET) is unclear.

METHODS/MATERIALS

The effect of PNI values before starting CDK 4/6i on patient prognosis was retrospectively analyzed.

RESULTS

A total of 431 patients were evaluated. After 35.7 months of follow-up, the median overall survival (mOS) was 46.3 months (95% CI, 29.7-62.8). The PNI-low group had decreased progression-free survival compared to the PNI-high group [16.6 vs. 30.5 months; univariate HR = 1.640, 95% confidence interval (CI): 1.281-2.099, P < .001]. The PNI-low group's mOS was noticeably shorter than the PNI-high group (35.0 months vs. not reached; multivariate-adjusted HR: 2.082, 95% CI: 1.398-3.102, P < .001). When stratified by CDK4/6i line: In patients using CDK4/6i as the first line, mPFS for the PNI-low and PNI-high group was 24.6 vs. 35.6 months (P = .026), and survival probabilities at 24, 36, and 48 months in the PNI-low and PNI-high groups were 75%, 62%, 57%, and 88%, 80%, and 72%, respectively (P = .002). In patients using CDK4/6i as the second line and after, mPFS was 8.2 vs.12.0 months (P = .014), and mOS was 18.6 vs. 39.6 months (P = .001) for the PNI-low and PNI-high group, respectively. The ORR and DCR were significantly lower in the low-PNI group than in the high-PNI group (P = .018 and P = .017, respectively). The incidence of grade 3-4 side effects due to CDK4/6is (39.8% vs. 30.7%, P = .046) was significantly greater in the PNI-low group than in the PNI-high group.

CONCLUSIONS

This study's results suggest that PNI is an easily measured and reliable indicator of prognosis in mBC patients treated with CDK4/6i and ET.

The prognostic and predictive value of the luminal-like subtype in hormone receptor-positive breast cancer: an analysis of the DATA trial

BACKGROUND

This study determines the prognostic value of the luminal-like subtype in patients with hormone receptor-positive breast cancer and explores whether the efficacy of extended anastrozole therapy differs between patients with luminal A-like versus luminal B-like tumours.

MATERIALS AND METHODS

The phase III DATA study (NCT00301457) examined the efficacy of 6 versus 3 years of anastrozole in postmenopausal women with early-stage hormone receptor-positive breast cancer who had received 2-3 years of tamoxifen. Patients with available formalin-fixed paraffin-embedded tissue blocks were identified and classified by immunohistochemical luminal-like subtype. Distant recurrence (DR) and breast cancer-specific mortality (BCSM) were compared by luminal-like subtype and treatment arm using competing risk methods.

RESULTS

This study included 788 patients: 491 had a luminal A-like tumour and 297 had a luminal B-like tumour. The median follow-up time was 13.1 years. Patients with luminal B-like tumours experienced a higher risk of DR [subdistribution hazard ratio (sHR) 1.44, 95% confidence interval (CI) 1.03-2.01, P = 0.03] and BCSM (sHR 1.68, 95% CI 1.15-2.45, P = 0.008) than patients with luminal A-like tumours. The efficacy of extended anastrozole therapy differed between patients with luminal A-like tumours (DR: sHR 0.51, 95% CI 0.30-0.88, P = 0.02; BCSM: sHR 0.39, 95% CI 0.19-0.82, P = 0.01) and patients with luminal B-like tumours (DR: sHR 2.09, 95% CI 0.96-4.53, P = 0.06; BCSM: sHR 2.36, 95% CI 0.80-7.00, P = 0.12) (P-interaction = 0.03 and P-interaction = 0.06, respectively).

CONCLUSION

In patients with hormone receptor-positive breast cancer, the luminal B-like subtype was associated with a significantly worse prognosis when compared with the luminal A-like subtype. Extended anastrozole therapy halved the risk of DR and BCSM in patients with luminal A-like tumours, whereas no effect was seen in patients with luminal B-like tumours.

Non-Luminal Disease Score for Everolimus in Patients with Hormone Receptor‑positive and Human Epidermal Growth Factor Receptor 2-Negative Advanced Breast Cancer: A Multicenter and Retrospective Study

Purpose

This study aims to explore the role of the non-luminal disease score (NOLUS) for everolimus in patients with hormone receptor-positive and human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer (ABC).

Methods

NOLUS has previously been established as an algorithm: NOLUS (0-100) = - 0.45 × ER(%) - 0.28 × PR(%) + 0.27 × Ki67(%) + 73. Information of cancer patients was retrospectively collected from three cancer centers in China.

Results

Totally, 198 HR+/HER2- ABC patients with complete records in expression rates (%) of ER, PR and Ki67 were enrolled in the study. The expression rates (%) of ER, PR, and Ki67 were 38.8 ± 27.9 versus 80.9 ± 14.2 (p < 0.001), 13.9 ± 14.3 versus 50.2 ± 30.4 (p < 0.001), and 37.8 ± 23.6 versus 28.7 ± 19.9 (p = 0.04), respectively, for NOLUS-positive patients and NOLUS-negative patients. For the overall population, the median PFS was 5.8 months versus 5.1 months in NOLUS-positive and NOLUS-negative patients (p = 0.16, HR = 0.75, 95% CI = 0.50, 1.12). The median 1L-, 2L, and 3L-PFS was 13.9 months versus 11.8 months (p = 0.22, HR = 1.63, 95% CI = 0.74, 3.62), 6.7 months versus 3.6 months (p = 0.08, HR = 0.34, 95% CI = 0.10, 1.18), and 4.6 months versus 4.0 months (p = 0.81, HR = 1.07, 95% CI = 0.63, 1.79) respectively, for NOLUS-positive patients and NOLUS-negative patients.

Conclusion

NOLUS-positive patients have a lower percentage of ER and PR, but a higher percentage of Ki67 index. The correlation between the benefits of everolimus and NOLUS failed to develop significance, suggesting that NOLUS may not be applicable in predicting everolimus efficacy in patients with HR+/HER2- ABC. Further research is expected.

Role of Oxidative Stress in the Occurrence, Development, and Treatment of Breast Cancer

Breast cancer is one of the most prevalent cancers worldwide. Recent studies have increasingly emphasized the role of oxidative stress in the initiation and progression of breast cancer. This article reviews how oxidative stress imbalance influences the occurrence and advancement of breast cancer, elucidating the intricate mechanisms through which reactive oxygen species (ROS) operate in this context and their potential therapeutic applications. By highlighting these critical insights, this review aims to enhance our understanding of oxidative stress as a potential target for innovative therapeutic strategies in the management of breast cancer.

Adding Anti-HER2 Therapy to Neoadjuvant Endocrine Therapy Seems Effective in Hormone Receptor and HER2 Positive Breast Cancer Patients Unfit for Chemotherapy: A Nationwide Population-Based Cohort Study

Introduction: Data are lacking on the optimal neoadjuvant systemic treatment (NST) for women with hormone receptor-positive (HR+) human epidermal growth factor receptor 2-positive (HER2+) breast cancer if they are unfit to receive the combination of chemotherapy and anti-HER2 therapy. The aim of this study was to determine whether the rates of ypT0 and ypN0 differ between patients treated with neoadjuvant endocrine therapy (NET) versus NET combined with anti-HER2 therapy (NET+aHER2). Materials and Methods: Data from the Netherlands Cancer Registry were analysed to identify women diagnosed with primary HR+/HER2+ breast cancer between 2008 and 2019, treated with either NET or NET+aHER2. The ypT0 and ypN0 rates were analysed (using uni- and multivariable logistic regression analyses, as applicable) in relation to the characteristics of the patient, the tumour, and the treatment. Results: Of the 190 patients identified (median age 77), 150 had been treated with NET and 40 with NET+aHER2. Patients with clinically node-positive disease (cN+) were significantly more likely to have been treated with NET+aHER2 (p = 0.029). The ypT0 rate was significantly higher after NET+aHER2, with 10.0% (4/40) versus 1.3% (2/150) following NET (p = 0.019). The ypN0 rate was significantly higher after NET+aHER2, with 25.0% (6/24) versus 5.5% (3/55) following NET in the cN+ patients (p = 0.020) and 81.3% (13/16) versus 55.8% (53/95) after NET in the cN- patients (p = 0.047). In the cN- patients, the ypN0 status was independently associated with age (p = 0.008) and the administration of NET+aHER2 (p = 0.016). Conclusions: The rates of ypT0 and ypN0 in women with HR+/HER2+ breast cancer treated with NST was significantly higher following NET+aHER2 than after NET.

COVID-19 vaccination anti-cancer impact on the PI3K/AKT signaling pathway in MC4L2 mice models

The most promising method of containing the COVID-19 pandemic is considered to be vaccination against SARS-CoV-2 infection. However, research on the relationship between vaccination against COVID-19 and cancer has primarily examined induced immunity rather than the disease itself. Considering that breast cancer is the most common cancer among women, the main goal of this study was to examine the impact of the Sinopharm and AstraZeneca vaccination on tumor characteristics such as tumor size, important tumor markers, tumor-infiltrating lymphocytes, metastasis to vital organs, and investigation of the PI3K/AKT signaling pathway, and the expression levels of relevant genes (PTEN, mTOR, AKT, PI3K, GSK3, and FoxO1) of the luminal B (MC4L2) mouse model. The tumor size of the mice was measured and monitored every two days, and after thirty days, the mice were euthanized. Remarkably, after vaccination, all vaccinated mice showed a decrease in the size of their tumor and an increase in the number of lymphocytes that had invaded the tumors. Tumor marker levels (VEGF, Ki-67, MMP-2/9), CD4/CD8 ratio, metastasis to vital organs, hormone receptors (ER, PR, and HER-2), and expression of genes related to the advancement of the PI3K/AKT signaling pathway were lower in vaccinated mice. Our research showed that the COVID-19 vaccine can have an anti-cancer effect by slowing the tumor progression and metastasis.

The use of nanomaterials as drug delivery systems and anticancer agents in the treatment of triple-negative breast cancer: an updated review (year 2005 to date)

Triple-negative breast cancer (TNBC) is characterised by the lack or low expression of estrogen, progesterone, and human epidermal growth factor receptor 2 receptors. TNBC has a high recurrence rate, swiftly metastasizes, and has a high mortality rate. Subsequently, the increase in cases of TNBC has signaled the need for treatment strategies with improved drug delivery systems. New diagnostic approaches, chemical entities, formulations particular those in the nanometric range have emerged after extensive scientific research as alternative strategies for TNBC treatment. As compared to contemporary cancer therapy, nanoparticles offer peculiar tunable features namely small size, shape, electrical charge, magnetic and fluorescent properties. Specifically in targeted drug delivery, nanoparticles have been demonstrated to be highly efficient in encapsulating, functionalization, and conjugation. Presently, nanoparticles have ignited and transformed the approach in photodynamic therapy, bioimaging, use of theranostics and precision medicine delivery in breast cancer. Correspondingly, recent years have witnessed a drastic rise in literature pertaining to treatment of TNBC using nanomaterials. Subsequently, this manuscript aims to present a state-of-the-art of nanomaterials advance on TNBC treatment; the ubiquitous utility use of nanomaterials such as liposomes, dendrimers, solid lipid nanomaterials, gold nanomaterials and quantum dots as anticancer agents and drug delivery systems in TNBC.

Recent progress of CDK4/6 inhibitors' current practice in breast cancer

Dysregulated cellular proliferation represents a hallmark feature across all cancers. Aberrant activation of the cyclin-dependent kinase 4 and 6 (CDK4/6) pathway, independent of mitogenic signaling, engenders uncontrolled breast cancer cell proliferation. Consequently, the advent of CDK4/6 inhibition has constituted a pivotal milestone in the realm of targeted breast cancer therapy. The combination of CDK4/6 inhibitors (CDK4/6i) with endocrine therapy (ET) has emerged as the foremost therapeutic modality for patients afflicted with hormone receptor-positive (HR + )/HER2-negative (HER2-) advanced breast cancer. At present, the Food and Drug Administration (FDA) has sanctioned various CDK4/6i for employment as the primary treatment regimen in HR + /HER2- breast cancer. This therapeutic approach has demonstrated a substantial extension of progression-free survival (PFS), often amounting to several months, when administered alongside endocrine therapy. Within this comprehensive review, we systematically evaluate the utilization strategies of CDK4/6i across various subpopulations of breast cancer and explore potential therapeutic avenues following disease progression during application of CDK4/6i therapy.

Combining Endocrine Therapy with Trastuzumab Emtansine Improves Progression-Free Survival and Overall Survival in HER2-Positive, Hormone Receptor-Positive Metastatic Breast Cancer

Background and Objectives: Patients with human epidermal growth factor receptor 2 (HER2) -positive, hormone receptor-positive (HR-positive) metastatic breast cancer (MBC) usually undergo trastuzumab emtansine (T-DM1) therapy in subsequent lines. Combining endocrine therapy (ET) with T-DM1 can improve treatment outcomes in this subtype. Therefore, this study aimed to investigate the benefits of using T-DM1 with ET in HER2-positive and HR-positive MBC. This study was the first to investigate the benefits of combining ET with T-DM1. Material and Methods: This study analyzed the medical records of patients with HER2-positive and HR-positive MBC who were treated with T-DM1 from June 2010 to December 2021. The patients were divided into groups based on whether they received concomitant ET with T-DM1. The primary endpoint was to determine the progression-free survival (PFS), while the secondary endpoints were overall survival (OS), objective response rate, and safety of the treatment. Results: Our analysis examined 88 patients, of whom 32 (36.4%) were treated with T-DM1 in combination with ET. The combination therapy showed a significant improvement in median PFS (15.4 vs. 6.4 months; p = 0.00004) and median OS (35.0 vs. 23.1 months; p = 0.026) compared to T-DM1 alone. The ORR was also higher in the combination group (65.6% vs. 29.3%; p = 0.026). Patients treated with pertuzumab priorly had reduced median PFS on T-DM1 compared to those who were not treated with pertuzumab (11.7 vs. 5.4 months, respectively; p < 0.01). T-DM1 demonstrated better median PFS in HER2 3+ patients compared to HER2 2+ patients, with an amplification ratio of >2.0 (10.8 vs 5.8 months, respectively; p = 0.049). The safety profiles were consistent with previous T-DM1 studies. Conclusions: The combination of T-DM1 with ET can significantly improve PFS and OS in patients with HER2-positive and HR-positive MBC. Our study suggests that prior pertuzumab treatment plus trastuzumab treatment might decrease T-DM1 efficacy.

Real-world treatment patterns of adjuvant endocrine therapy and ovarian suppression in premenopausal HR+/HER2+ breast cancer

BACKGROUND

The optimal adjuvant endocrine therapy (ET) in hormone receptor positive (HR+) and human epidermal growth factor receptor 2 positive (HER2+) premenopausal breast cancer (BC) remains unclear. Moreover, the benefit and clinical indications of ovarian suppression (OS) is poorly elucidated. We described real-world patterns surrounding choice of ET and clinicopathologic features which predicted treatment with OS in a contemporary cohort of premenopausal women with HR+/HER2+ BC.

METHODS

This retrospective analysis included premenopausal patients with nonmetastatic HR+/HER2+ BC from the CancerLinQ Discovery database from January 2010 to May 2020. Women were less than 50 years and received chemotherapy, anti-HER2 therapy, and ET. They were categorized into 1 of 4 groups based on type of ET prescribed at initiation: aromatase inhibitor (AI) + OS, OS, tamoxifen + OS, or tamoxifen. Multivariable logistic regression assessed associations between clinicopathologic features and OS use.

RESULTS

Out of 360,540 patients with BC, 937 were included. The majority (n = 818, 87%) were prescribed tamoxifen, whereas 4 (0.4%), 50 (5.3%), and 65 (6.9%) received OS, tamoxifen + OS and AI + OS, respectively. No clinicopathologic features predicted OS use apart from age; patients <35 years were more likely to receive OS compared with those ≥35 years (odds ratio 2.33, p < 0.001).

CONCLUSIONS

This is the first real-world study evaluating ET treatment patterns in HR+/HER2+ premenopausal BC. OS use was uncommon and the majority received tamoxifen as the preferred ET regardless of most clinicopathologic risk factors. Additional research is needed to optimize ET decisions in young women with this distinct BC subtype.

Distinct ER and PR expression patterns significantly affect the clinical outcomes of early HER2-positive breast cancer: A real-world analysis of 871 patients treated with neoadjuvant therapy

INTRODUCTION

The impact of distinct estrogen receptor (ER) and progesterone receptor (PR) expression patterns on tumor behavior and treatment outcomes within HER2-positive breast cancer is not fully explored. This study aimed to comprehensively examine the clinical differences among patients with HER2-positive breast cancer harboring distinct ER and PR expression patterns in the neoadjuvant setting.

METHODS

This retrospective analysis included 871 HER2-positive breast patients treated with neoadjuvant therapy at our hospital between 2011 and 2022. Comparisons were performed across the three hormone receptor (HR)-specific subtypes, namely the ER-negative/PR-negative/HER2-positive (ER-/PR-/HER2+), the single HR-positive (HR+)/HER2+, and the triple-positive breast cancer (TPBC) subtypes.

RESULTS

Of 871 patients, 21.0% had ER-/PR-/HER2+ tumors, 33.6% had single HR+/HER2+ disease, and 45.4% had TPBC. Individuals with single HR+/HER2+ tumors and TPBC cases demonstrated significantly lower pathological complete response (pCR) rates compared to those with ER-/PR-/HER2+ tumors (36.9% vs. 24.3% vs. 49.2%, p < 0.001). Multivariate analysis confirmed TPBC as significantly associated with decreased pCR likelihood (OR = 0.42, 95%CI 0.28-0.63, p < 0.001). Survival outcomes, including disease-free survival (DFS) and overall survival (OS), showed no significant differences across HR-specific subtypes in the overall patient population. However, within patients without anti-HER2 therapy, TPBC was linked to improved DFS and a trend towards better OS.

CONCLUSIONS

HER2-positive breast cancer exhibited three distinct HR-specific subtypes with varying clinical manifestations and treatment responses. These findings suggest personalized treatment strategies considering ER and PR expression patterns, emphasizing the need for further investigations to unravel molecular traits underlying HER2-positive breast cancer with distinct HR expression patterns.

Real-world study of palbociclib combined with endocrine therapy for patients with metastatic breast cancer: A comparison of subsequent treatment patterns and HER2 expression analysis

BACKGROUND

Cyclin-dependent kinase 4/6 inhibitors combined with endocrine therapy (ET) comprise the standard treatment for patients with hormone receptor-positive and human epidermal growth factor 2 (HER2)-negative metastatic breast cancer. The optimal systematic treatment after progression on palbociclib and the role of HER2 expression among these patients remain unclear.

METHODS

The authors retrospectively identified 361 patients who received palbociclib combined with ET. Progression-free survival (PFS) and overall survival (OS) were analyzed based on subsequent treatments and HER2 status (PFSsub and OSsub, respectively). PFS1 and OS1 were calculated from palbociclib administration to disease progression/death and death from any cause, respectively. PFSsub and OSsub were calculated from subsequent treatment initiation.

RESULTS

The median PFS1 and OS1 were 10.2 and 39.9 months, respectively. The median PFSsub and OSsub of 111 patients (54.7%) who received chemotherapy were 4.9 months and 20.0 months, respectively, whereas those of 89 patients (43.8%) who received endocrine backbone therapy were 5.9 months and 29.3 months, respectively. Among them, 31 patients (15.3%) who received abemaciclib combined with new ET showed better PFSsub and OSsub (12.2 months and not reached, respectively). The median PFS1 was significantly shorter in the HER2-low subgroup than in the HER2-zero subgroup among patients who received second-line or later palbociclib (6.1 vs. 7.8 months; p = .040) but did not differ among patients who received first-line palbociclib.

CONCLUSIONS

Various regimens after palbociclib use were received. An improvement was noted in PFS among patients who received endocrine backbone therapy relative to chemotherapy, which may have been secondary to the receipt of chemotherapy by patients with more aggressive disease. HER2 status was not related to the effect of first-line palbociclib, but it may play a role in later lines.

Hexachlorobenzene as a differential modulator of the conventional and metronomic chemotherapy response in triple negative breast cancer cells

Aim

Triple negative breast cancer (TNBC) is usually treated with high doses of paclitaxel, whose effectiveness may be modulated by the action of environmental contaminants such as hexachlorobenzene. High doses of paclitaxel cause adverse effects such as low cellular selectivity and the generation of resistance to treatment due to an increase in the expression of multidrug resistance proteins (MRPs). These effects can be reduced using a metronomic administration scheme with low doses. This study aimed to investigate whether hexachlorobenzene modulates the response of cells to conventional chemotherapy with paclitaxel or metronomic chemotherapy with paclitaxel plus carbachol, as well as to study the participation of the MRP ATP-binding cassette transporter G2 (ABCG2) in human TNBC MDA-MB231 cells.

Methods

Cells were treated with hexachlorobenzene alone or in combination with conventional or metronomic chemotherapies. The effects of treatments on cell viability were determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and the nuclear factor kappa B pathway participation was evaluated using a selective inhibitor. ABCG2 expression and its modulation were determined by western blot.

Results

Results confirmed that paclitaxel reduces MDA-MB231 cell viability in a concentration-dependent manner. Results also showed that both conventional and metronomic chemotherapies reduced cell viability with similar efficacy. Although hexachlorobenzene did not modify cell viability per se, it did reverse the effect induced by the conventional chemotherapy, without affecting the efficacy of the metronomic chemotherapy. Additionally, a differential modulation of ABCG2 expression was determined, mediated by the nuclear factor kappa B pathway, which was directly related to the modulation of cell sensitivity to another cycle of paclitaxel treatment.

Conclusions

The findings indicate that, in human TNBC MDA-MB231 cells, in the presence of hexachlorobenzene, the metronomic combination of paclitaxel plus carbachol is more effective in affecting the tumor biology than the conventional therapeutic administration scheme of paclitaxel.

Targeted Therapies and Drug Resistance in Advanced Breast Cancer, Alternative Strategies and the Way beyond

"Targeted therapy" or "precision medicine" is a therapeutic strategy launched over two decades ago. It relies on drugs that inhibit key molecular mechanisms/pathways or genetic/epigenetic alterations that promote different cancer hallmarks. Many clinical trials, sponsored by multinational drug companies, have been carried out. During this time, research has increasingly uncovered the complexity of advanced breast cancer disease. Despite high expectations, patients have seen limited benefits from these clinical trials. Commonly, only a minority of trials are successful, and the few approved drugs are costly. The spread of this expensive therapeutic strategy has constrained the resources available for alternative research. Meanwhile, due to the high cost/benefit ratio, other therapeutic strategies have been proposed by researchers over time, though they are often not pursued due to a focus on precision medicine. Notable among these are drug repurposing and counteracting micrometastatic disease. The former provides an obvious answer to expensive targeted therapies, while the latter represents a new field to which efforts have recently been devoted, offering a "way beyond" the current research.

The inhibitory effect of trastuzumab on BT474 triple‑positive breast cancer cell viability is reversed by the combination of progesterone and estradiol

Breast cancer expressing the estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER2) is known as triple-positive (TPBC). TPBC represents 9-11% of breast cancer cases worldwide and is a heterogeneous subtype. Notably, TPBC presents a therapeutic challenge due to the crosstalk between the hormonal (ER and PR) and HER2 pathways. Patients with TPBC are treated with trastuzumab (TTZ); however, several patients treated with TTZ tend to relapse. The present study aimed to investigate the effect of the PR on inhibitory effect of TTZ on cell viability. BT474 cells (a model of TPBC) and BT474 PR-silenced cells were treated with either TTZ, progesterone (Pg), the PR antagonist mifepristone (RU486) or estradiol (E2) alone or in combination for 144 h (6 days). Cell viability assays and western blotting were subsequently performed. The results showed that Pg and E2 interfered with the inhibitory effect of TTZ on cell viability and this effect was potentiated when both hormones were combined. Pg was revealed to act through the PR, mainly activating the PR isoform B (PR-B) and inducing the protein expression levels of CDK4 and cyclin D1; however, it did not reactivate the HER2/Akt pathway. By contrast, E2 was able to increase PR isoform A (PR-A) expression, which was inhibited by Pg. Notably, in most of the experiments, RU486 did not antagonize the effects of Pg. In conclusion, Pg and E2 may interfere with the inhibitory effect of TTZ on cell viability through PR-B activation and PR-A inactivation.

Efficacy of everolimus-based therapy in advanced triple-positive breast cancer: Experience from three cancer centers in China

BACKGROUND

Triple-positive breast cancer (TPBC) is highly invasive and lacks well-established treatment strategies, especially in patients with advanced stage disease. This study aimed to explore the efficacy of everolimus in patients with metastatic TPBC (mTPBC) in a multicenter real-world setting.

METHODS

A total of 2518 cancer patients who received everolimus-based therapy were enrolled from three cancer institutes in China from 2014 to 2022. Their clinicopathological characteristics were collected from medical records. The indicators for the efficacy of everolimus were progression-free survival (PFS), objective response rate (ORR) and clinical benefit rate (CBR).

RESULTS

We collected 79 HER2-enriched patients that were treated with everolimus-based therapy, 43 of whom were mTPBC. The most commonly used therapeutic combinations was everolimus plus endocrine therapy (18/43, 41.9%). Among all combinations, everolimus plus chemotherapy plus trastuzumab developed the longest PFS of 10.9 months (95% CI: 1.5-20.3). Seventeen patients (32.6%) with mTPBC received everolimus as frontline treatment (1 L/2 L/3 L, FL), and 26 patients (67.4%) as backline treatment (>3 L, BL). Among all the population, the median PFS for everolimus was 4.5 months (range: 3.0-6.0), ORR was 30.2%, and CBR was 48.8%. PFSFL of 10.9 months was significantly longer than 4.0 months for PFSBL (p = 0.003, HR = 0.31, 95% CI: 0.14-0.67). ORRFL was 41.2%, showing no significance compared to ORRBL of 23.1% (one-sided p = 0.11). CBRFL was observed better of 76.5% versus CBRBL of 46.2% (one-sided p = 0.026).

CONCLUSION

Everolimus as frontline treatment achieves clinical benefits for Chinese patients with mTPBC, which may provide some references for the management of Chinese mTPBC patients.

Microswimmer-Assisted Dual-Signal Sensor for Multiple Targets in Whole Blood

Accurate detection of biomarkers in whole blood is an important aspect of diagnostic testing but remains a challenge due to various interferences. However, using a self-calibrating two-signal strategy offers a solution that can overcome interference caused by experimental and environmental factors. Here, we proposed a novel microswimmer {methylene blue (MB)@ZIF-90@aptamer-HER2/3,3',5,5'-tetramethylbenzidine (TMB)@ZIF-90@aptamer-ER}-dual-signal (electrochemical and fluorescence) homogeneous sensor based on functionalized ZIF nanomaterials for one-step simultaneous detection of human epidermal growth factor receptor-2 (HER2) and estrogen receptor (ER) in whole blood. The proposed one-step ZIF-90 synthesis encapsulates TMB and MB with dual-signal properties. HER2 and ER aptamers adsorbed on MB@ZIF-90/TMB@ZIF-90 function as the gate switches. The microswimmer targets the HER2 and ER with adenosine triphosphate (ATP)-driven motion. When targets are present, aptamers dissociate and reduce the microswimmer's surface negative charge. The microswimmer undergoes attack and decomposition by swimming ATP due to the strong coordination force between ATP and Zn2+, leading to the release of MB and TMB. The negative charges on the surface of indium tin oxide enrich MB and TMB with positive charges, thereby increasing the intensities of electrochemical and fluorescence signals. The detection process was completed within 40 min, and the detection limits for ER and HER2 were 8.1 and 5.7 fg/mL respectively, with a linear range of 0.25-20 pg/mL.

The Role of Female Reproductive Hormones in the Association between Migraine and Breast Cancer: An Unanswered Question

Accumulating epidemiological studies have investigated a possible interconnection between migraine (Mi) and breast cancer (BC) because of the strong link between these diseases and female reproductive hormones. This review aims to consolidate findings from epidemiological studies and explore biologically plausible hypothetical mechanisms related to hormonal pathways. Current evidence suggests a protective role of Mi in BC development, particularly in case-control studies but not in cohort ones. The inconsistency among studies may be due to several reasons, including diagnostic criteria for Mi and the age gap between the development of these two diseases. Furthermore, recent research has challenged the concept of a net beneficial effect of Mi on BC, suggesting a more complex relationship between the two conditions. Many polymorphisms/mutations in hormone-related pathways are involved in at least one of the two conditions. The most promising evidence has emerged for a specific alteration in the estrogen receptor 1 gene (rs2228480). However, the possible specific mutation or polymorphism involved in this association has not yet been identified. Further studies with robust methodologies are needed to validate the protective role of Mi in BC and fully elucidate the precise nature of this causal relationship.

Nuclear and Cytoplasmic hTERT, Tumor-Infiltrating Lymphocytes, and Telomere Elongation Leukocytes Are Independent Factors in the Response to Neoadjuvant Treatment in HER2-Enriched Breast Cancer

HER2-enriched tumors are responsible for 20% of breast tumors and have high rates of immune infiltrates in the tumor stroma that respond favorably to neoadjuvant chemotherapy. In the context of tumors, telomeres control cell death and prevent tumor cells from replicating discontinuously, leading to their immortalization. This study aimed to evaluate the presence of tumor-infiltrating lymphocytes, hTERT expression, hTERT promoter mutation, and leukocyte telomere length in HER2-enriched breast tumors. A total of 103 cases were evaluated, 19 with pathologic complete response. The TILs percentage was above ≥10 in 44 cases (43%) and significantly present in patients ≥50 years of age. hTERT staining positivity was mostly nuclear, significantly present in the non-pCR group, and associated with a lower survival rate. Leukocyte telomeres were elongated for HER2-enriched tumors, and in multivariate analysis, shortening was associated with an increased risk of death. Overall, our results show that the nuclear and cytoplasmic presence of hTERT may indicate a worse prognosis and that leukocyte telomere elongation is a protective factor.

Outcomes for the first four lines of therapy in patients with HER2-positive advanced breast cancer: results from the SONABRE registry

PURPOSE

We assessed the systemic treatment choices and outcomes in patients diagnosed with human epidermal growth factor receptor-2-positive (HER2 +) advanced breast cancer (ABC), for the first four lines of systemic therapy and by hormone receptor (HR) status.

METHODS

We identified 330 patients diagnosed with HER2 + ABC in 2013-2018 in the Southeast of The Netherlands, of whom 64% with HR + /HER2 + and 36% with HR-/HER2 + disease. Overall survival (OS) from start of therapy was calculated using the Kaplan-Meier method.

RESULTS

In real world, 95% of patients with HR + /HER2 + and 74% of patients with HR-/HER2 + disease received systemic therapy. In HR + /HER2 + disease, use of endocrine, chemo- and HER2-targeted therapy was , respectively, 64%, 46% and 60% in first line, and 39%, 64% and 75% in fourth line. In HR-/HER2 + disease, 91-96% of patients received chemotherapy and 77-91% HER2-targeted therapy, irrespective of line of therapy. In patients with HR + /HER2 + disease, median OS was 34.9 months (95%CI:25.8-44.0) for the first line and 12.8 months (95%CI:10.7-14.9) for the fourth line. In HR-/HER2 + disease, median OS was 39.9 months (95%CI:23.9-55.8) for the first line and 15.2 months (95%CI:10.9-19.5) for the fourth line. For patients treated with first-line pertuzumab, trastuzumab plus chemotherapy, median OS was not reached at 56.0 months in HR + /HER2 + disease and 48.4 months (95%CI:32.6-64.3) in HR-/HER2 + disease.

CONCLUSION

Survival times for later lines of therapy are surprisingly long and justify the use of multiple lines of systemic therapy in well-selected patients with HER2 + ABC. Our real-world evidence adds valuable observations to the accumulating evidence that within HER2 + ABC, the HR status defines two distinct disease subtypes.

Unlocking the Resistance to Anti-HER2 Treatments in Breast Cancer: The Issue of HER2 Spatial Distribution

Approximately 15% of breast cancers are classified as HER2-positive, with an amplification of the ERBB2 gene and/or an overexpression of the HER2 protein. Up to 30% of HER2-positive breast cancers shows heterogeneity in HER2 expression and different patterns of spatial distribution, i.e., the variability in the distribution and expression of the HER2 protein within a single tumour. Spatial heterogeneity may potentially affect treatment, response, assessment of HER2 status and consequently, may impact on the best treatment strategy. Understanding this feature can help clinicians to predict response to HER2-targeted therapies and patient outcomes, and to fine tune treatment decisions. This review summarizes the available evidence on HER2 heterogeneity and spatial distribution and how this may affect current available treatment choices, exploring possible opportunities for overcoming this issue, such as novel pharmacological agents, belonging to the group of antibody-drug conjugates.

Addition of endocrine therapy to dual anti-HER2 targeted therapy in initial treatment of HER2 + /HR + metastatic breast cancer

PURPOSE

Dual anti-HER2 targeted therapy and chemotherapy is the current first-line standard of care for HER2 + metastatic breast cancer (MBC), with endocrine therapy (ET) the backbone of treatment in hormone receptor positive (HR +) disease. The potential ET benefit in HER2 + /HR + patients is unknown as pivotal dual anti-HER2 clinical trials precluded ET use.

METHODS

Real-world data from a multi-site registry of consecutive HER2 + MBC patients treated at clinician discretion were examined. Patients that were HR + (ER + and/or PR +) and had received first-line chemotherapy alongside trastuzumab and pertuzumab were explored. Of 362 patients in the registry, 215 were excluded due to being HR- (n = 210) or not receiving chemotherapy (n = 5).

RESULTS

Of the 147 patients included, 91 (62%) received concurrent ET and 56 (38%) had not. Comparing the groups, there were no significant differences in age, performance status, metastatic sites, use of previous therapy and de novo metastatic disease. More patients with ER + PR + disease versus those with ER + PR- or ER-PR + received ET (73 vs 45%). The addition of ET was associated with significantly improved 5-year PFS (HR 0.58, CI 0.37-0.89, p = 0.014) and OS (HR 0.52, CI 0.31-0.90, p = 0.018), with no increase in adverse events noted.

CONCLUSION

The addition of ET to first-line dual anti-HER2 therapy post chemotherapy in patients with HER2 + /HR + MBC was associated with major gains in PFS and OS with no safety concerns evident. Further studies of this combination are justified, along with studies of how best to integrate other agents that are active in this patient subset, including CDK4/6 inhibitors.

Analysis of the clinicopathological characteristics and prognosis of triple-positive breast cancer and HER2-positive breast cancer-A retrospective study

Background

Adjuvant chemotherapy and targeted therapy have become standard postoperative therapeutic modalities for human epidermal growth factor receptor 2 (HER2)-positive breast cancer(HER2-positive,HR-negative), including triple-positive breast cancer(HER2-positive,HR-positive). However, these two types of breast cancer differ in terms of pathogenesis. This article analyzes these two types of breast cancer by comparing their prognoses.

Methods

The clinicopathological characteristics of 135 patients, including 60 patients with triple-positive breast cancer and 75 patients with HER2-positive breast cancer, were analyzed to compare the disease-free survival (DFS) and overall survival (OS) of the two groups over a 5-year period. A multifactorial Cox risk model was constructed by grouping age, menstrual status, maximum tumor diameter, number of lymph node metastases, pathological staging, and Ki-67 staining results. All statistical data were analyzed in detail using SPSS25.0 statistical software.

Results

The 5-year OS rates of patients with breast cancer in the triple-positive and HER2-positive groups were 96.7% and 82.7%, respectively, and the 5-year DFS rates were 90% and 73.3%, respectively. The Cox results revealed that molecular staging was an independent factor affecting recurrent metastasis and survival of breast cancer patients (hazard ratio [HR] =2.199, 95% confidence interval [CI], 1.296-8.266; HR = 9.994, 95% CI, 2.019-49.465).

Conclusion

The 5-year DFS and OS rates were significantly better in the triple-positive group than in the HER2-positive group. Subgroups received different prognosis for different chemotherapy regimens. Breast cancer patients should be treated according to the risk of recurrence with symptomatic treatment and precise regulation.

Clinical implications of the intrinsic molecular subtypes in hormone receptor-positive and HER2-negative metastatic breast cancer

Traditionally, the classification of breast cancer relies on the expression of immunohistochemical (IHC) biomarkers readily available in clinical practice. Using highly standardized and reproducible assays across patient cohorts, intrinsic molecular subtypes of breast cancer - also called "intrinsic subtypes" (IS) - have been identified based on the expression of 50 genes. Although IHC-based subgroups and IS moderately correlate to each other, they are not superimposable. In fact, non-luminal biology has been detected in a substantial proportion (5-20%) of hormone receptor-positive (HoR+) tumors, has prognostic value, and identifies reduced and increased sensitivity to endocrine therapy and chemotherapy, respectively. During tumor progression, a shift toward a non-luminal estrogen-independent and more aggressive phenotype has been demonstrated. Intrinsic genomic instability and cell plasticity, alone or combined with external constraints deriving from treatment selective pressure or interplay with the tumor microenvironment, may represent the determinants of such biological diversity between primary and metastatic disease, and during metastatic tumor evolution. In this review, we describe the distribution and the clinical behavior of IS as the disease progresses, focusing on HoR+/HER2-negative advanced breast cancer. In addition, we provide an overview of the ongoing clinical trials aiming to validate the predictive and prognostic value of IS towards their incorporation into routine care.

A multicentre single arm phase 2 trial of neoadjuvant pyrotinib and letrozole plus dalpiciclib for triple-positive breast cancer

Current therapies for HER2-positive breast cancer have limited efficacy in patients with triple-positive breast cancer (TPBC). We conduct a multi-center single-arm phase 2 trial to test the efficacy and safety of an oral neoadjuvant therapy with pyrotinib, letrozole and dalpiciclib (a CDK4/6 inhibitor) in patients with treatment-naïve, stage II-III TPBC with a Karnofsky score of ≥70 (NCT04486911). The primary endpoint is the proportion of patients with pathological complete response (pCR) in the breast and axilla. The secondary endpoints include residual cancer burden (RCB)-0 or RCB-I, objective response rate (ORR), breast pCR (bpCR), safety and changes in molecular targets (Ki67) from baseline to surgery. Following 5 cycles of 4-week treatment, the results meet the primary endpoint with a pCR rate of 30.4% (24 of 79; 95% confidence interval (CI), 21.3-41.3). RCB-0/I is 55.7% (95% CI, 44.7-66.1). ORR is 87.4%, (95% CI, 78.1-93.2) and bpCR is 35.4% (95% CI, 25.8-46.5). The mean Ki67 expression reduces from 40.4% at baseline to 17.9% (P < 0.001) at time of surgery. The most frequent grade 3 or 4 adverse events are neutropenia, leukopenia, and diarrhoea. There is no serious adverse event- or treatment-related death. This fully oral, chemotherapy-free, triplet combined therapy has the potential to be an alternative neoadjuvant regimen for patients with TPBC.

Integrating new oral selective oestrogen receptor degraders in the breast cancer treatment

PURPOSE OF REVIEW

Oral SERDs are under extensive development to overcome fulvestrant main limitations, including intramuscular-only formulation and poor performance in early-stage hormone receptor-positive (HR+)/HER2-negative breast cancer. This review summarizes the most relevant evidence published so far and envisions the potential integration of oral SERDs in the therapeutic algorithm of HR+/HER2-negative metastatic breast cancer (MBC).

RECENT FINDINGS

Amcenestrant and giredestrant, two of the most promising oral SERDs, recently failed to show a significant improvement in progression-free survival (PFS) in pivotal trials. Conversely, elacestrant demonstrated significant PFS superiority over standard-of-care endocrine therapy (aromatase inhibitors or fulvestrant) in MBC. Additionally, it did not show unusual side effects observed with other oral SERDs, like bradycardia, hematotoxicity and vision impairment, and proved to be effective also in case of ESR1 -mutant endocrine-resistant breast cancer. Combination trials of oral SERDs with target agents, such as CDK4/6-inhibitors, are ongoing. Finally, some window-of-opportunity trials showed promising on-target activity in early-stage for this drug class.

SUMMARY

Promising results from early-phase trials are not translating into sufficient clinical benefit in pivotal trials of main oral SERDs in monotherapy, except for elacestrant. Whether oral SERDs might become the backbone for combination strategies in MBC or the preferred (neo)adjuvant endocrine agents is under evaluation.

Controversial topics in metastatic HR+/HER2- breast cancer: Guiding treatment by a modified Delphi approach

The treatment of HR+/HER2- metastatic breast cancer with cyclin-dependent kinases 4 and 6 inhibitors combined with endocrine therapy has recently emerged as the most relevant therapeutic strategy. However, in routine clinical practice, the best therapeutic approach in patients with comorbidities at early relapsing or ab initio metastatic disease, PI3KCA mutation, is still debated among oncologists. Given these areas of uncertainty, we conducted a Delphi survey to describe and confront the level of agreement or disagreement between clinicians working in referral vs local spoke oncological hospitals and summarize a consensus on these debated topics. In total, 56 items were drafted using the Nominal Group Technique and used for the Delphi Survey. A total of 46 clinicians participated in the survey. Overall, the consensus threshold among all participants was reached in 46/56 items (82%), and Delphi Survey results showed a high level of consensus. For the 10 items (18%) that did not reach the consensus threshold, possible explanations considering differences in clinical practice and recent findings from literature are provided in the Discussion. Outcomes from the present survey may help guide treatment in multiple comorbidities, early recurring and ab initio metastatic disease, and PI3KCA mutation, where evidence from randomized trials and level 1 evidence is currently missing.

Efficacy and Safety of Pyrotinib in Human Epidermal Growth Factor Receptor 2-Positive Advanced Breast Cancer: A Multicenter, Retrospective, Real-World Study

Purpose

Pyrotinib, a novel human epidermal growth factor receptor 2 (HER2)-targeted tyrosine kinase inhibitor (TKI), has led to remarkable survival outcomes in HER2-positive advanced breast cancer (ABC) in clinical trials and was approved for second-line standards of treatment for HER2+ ABC in China. However, the clinical trials could not fully reflect reality of clinical practice, and predictive factors were still lacking. This study aimed to assess the actual efficacy and safety of pyrotinib in HER2+ ABC in real-world setting.

Patients and Methods

In this multicenter, retrospective, observational real-world study, we analyzed 171 patients with HER2+ ABC, who received pyrotinib-based treatment from November 2017 to November 2020. The primary end point was progression-free survival (PFS). Secondary end points included overall survival (OS), objective response rate (ORR), clinical benefit rate (CBR) and safety.

Results

Up to November 30, 2021, the median PFS (mPFS) was 12.0 months for all patients. One hundred and sixty-two patients (94.7%) with measurable lesions had been included in efficacy assessment. The ORR and CBR were 45.1% and 81.5%, respectively. A significantly longer PFS was reported in patients who received pyrotinib as first-line treatment, had the ECOG-PS of 0–1, as well as those who were lapatinib-naive. In addition, multivariable analysis indicated that ECOG-PS of 2–4, positive hormone receptor (HR) status, and presence of visceral metastasis were independent negative predictors of PFS. As far as we know, this study first reported the survival outcome of pyrotinib cross-line treatment, with a mPFS of 5.0 months. All grades of adverse events (AEs) occurred in 171 patients (100%), and the most common AE was diarrhea (86.5%).

Conclusion

This study further demonstrated the outstanding efficacy and safety of pyrotinib and reported the potential predictors of survival in HER2+ ABC.

The antiviral drug telaprevir induces cell death by reducing FOXA1 expression in estrogen receptor α ( ERα )‐positive breast cancer cells

Previously, we found that telaprevir (Tel), the inhibitor of hepatitis C virus NS3/4A serine protease, reduces estrogen receptor α (ERα) content at the transcriptional level without binding to the receptor, prevents ERα transcriptional activity, and inhibits basal and 17β‐estradiol (E2)‐dependent cell proliferation in different breast cancer (BC) cell lines. Here, we further characterize the Tel action mechanisms on ERα levels and function, identify a possible molecular target of Tel in BC cells, and evaluate Tel as an antiproliferative agent for BC treatment. Tel‐dependent reduction in ERα levels and function depends on a Tel‐dependent decrease in FOXA1 levels and activity. The effect of Tel is transduced by the IGF1‐R/AKT/FOXA1 pathway, with the antiviral compound interacting with IGF1‐R. Tel prevents the proliferation of several BC cell lines, while it does not affect the proliferation of normal nontransformed cell lines, and its antiproliferative effect is correlated with the ratio of FOXA1/IGF1‐R expression. In conclusion, Tel interferes with the IGF1‐R/AKT/FOXA1 pathway and induces cell death in ERα‐expressing BC cells. Thus, we propose that this antiviral could be repurposed for the treatment of ERα‐expressing BC.

Immune effects of CDK4/6 inhibitors in patients with HR+/HER2− metastatic breast cancer: Relief from immunosuppression is associated with clinical response

Background

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) are innovative small target molecules that, in combination with endocrine therapy, have recently been employed in the treatment of patients with HR⁺/HER2⁻ metastatic breast cancer (mBC). In this prospective study, we investigate the impact of CDK4/6i on the immune profile of patients with HR⁺/HER2⁻ mBC.

Methods

Immune cell subsets were analysed using flow cytometry of peripheral blood mononuclear cells (PBMCs) isolated from patients with HR⁺/HER2⁻ mBC, both before and during treatment. Regulatory T cells (Tregs) were identified using the markers CD4, CD25, CTLA4, CD45RA, and intracellular FOXP3. Monocytic and polymorphonuclear myeloid-derived suppressor cells (M-MDSCs and PMN-MDSCs) and other immune populations were analysed using CD45, CD14, CD66b, CD11c, HLA-DR, CD3, CD8, CD28, CD137, PD1, CD45RA, CCR7, and Ki67.

Findings

The percentage of circulating Tregs and M/PMN-MDSCs was significantly downregulated from baseline during CDK4/6i-treatment (p<0.0001 and p<0.05, respectively). In particular, the effector Treg subset (CD4⁺CD25⁺FOXP3^highCD45RA⁻) was strongly reduced (p<0.0001). The decrease in Treg levels was significantly greater in responder patients than in non-responder patients. Conversely, CDK4/6i treatment was associated with increased levels of CD4⁺ T cells and anti-tumour CD137⁺CD8⁺ T cells (p<0.05).

Interpretation

CDK4/6i treatment results in downregulation of Tregs, M-MDSCs, and PMN-MDSCs, thus weakening tumour immunosuppression. This decrease is associated with response to treatment, highlighting the importance of unleashing immunity in cancer treatment efficacy. These results suggest a novel mechanism of immunomodulation in mBC and provide valuable information for the future design of novel treatments combining CDK4/6i with immunotherapy in other cancer settings.

Funding

Sapienza University of Rome.

Dalpiciclib Combined With Pyrotinib and Letrozole in Women With HER2-Positive, Hormone Receptor-Positive Metastatic Breast Cancer (LORDSHIPS): A Phase Ib Study

Purpose

The LORDSHIPS study aimed to explore the safety and efficacy of a novel fully oral triplet combination of dalpiciclib (a potent cyclin-dependent kinase 4/6 inhibitor), pyrotinib (a HER2 tyrosine kinase inhibitor) and endocrine therapy letrozole in patients with HER2-positive, hormone receptor (HR)-positive metastatic breast cancer (MBC) in the front-line setting.

Patients and Methods

Postmenopausal women with HER2-positive, HR-positive MBC were recruited in the dose-finding phase Ib trial. A standard 3 + 3 design was used to determine safety, tolerability, and recommended phase II dose (RP2D) for the combination.

Results

A total of 15 patients were enrolled to three dose combination cohorts (letrozole/pyrotinib/dalpiciclib, level/I: 2.5/400/125 mg, n=5; level/L1: 2.5/400/100 mg, n=6; level/L2: 2.5/320/125 mg, n=4). Three patients experienced dose-limiting toxicities (level/I, n=2; level/L1, n=1) and level/L2 was identified as RP2D. The most frequent grade 3-4 adverse events were neutropenia (46.7%), leukopenia (40.0%), oral mucositis (26.7%) and diarrhea (20.0%). The confirmed objective response rate (ORR) was 66.7% (95% CI: 38.4% to 88.2%). The confirmed ORR of study treatment as first line (1L) and second line (2L) HER2-targeted therapy was 85.7% (6/7) and 50.0% (4/8), respectively. Median progression-free survival (PFS) was 11.3 months (95% CI: 5.3 months to not reached). PFS in 1L setting was not reached yet, while PFS in 2L setting was 10.9 months (95% CI: 1.8 to 13.7 months).

Conclusions

The fully oral combination of dalpiciclib, pyrotinib and letrozole is a promising chemotherapy-sparing treatment option for HER2-positive, HR-positive MBC patients. The planned dose-expansion phase II study is ongoing.

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT03772353.

The initial hormone receptor/HER2 subtype is the main determinator of subtype discordance in advanced breast cancer: a study of the SONABRE registry

Purpose

The hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) are the main parameters in guiding systemic treatment choices in breast cancer, but can change during the disease course. This study aims to evaluate the biopsy rate and receptor subtype discordance rate in patients diagnosed with advanced breast cancer (ABC).

Methods

Patients diagnosed with ABC in seven hospitals in 2007–2018 were selected from the SOutheast Netherlands Advanced BREast cancer (SONABRE) registry. Multivariable logistic regression analyses were performed to identify factors influencing biopsy and discordance rates.

Results

Overall, 60% of 2854 patients had a biopsy of a metastatic site at diagnosis. One of the factors associated with a reduced biopsy rate was the HR + /HER2 + primary tumor subtype (versus HR + /HER2- subtype: OR = 0.68; 95% CI: 0.51–0.90). Among the 748 patients with a biopsy of the primary tumor and a metastatic site, the overall receptor discordance rate was 18%. This was the highest for the HR + /HER2 + primary tumor subtype, with 55%. In 624 patients with metachronous metastases, the HR + /HER2 + subtype remained the only predictor significantly related to a higher discordance rate, irrespective of prior (neo-)adjuvant therapies (OR = 7.49; 95% CI: 3.69–15.20).

Conclusion

The HR + /HER2 + subtype has the highest discordance rate, but the lowest biopsy rate of all four receptor subtypes. Prior systemic therapy was not independently related to subtype discordance. This study highlights the importance of obtaining a biopsy of metastatic disease, especially in the HR + /HER2 + subtype to determine the most optimal treatment strategy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06472-5.

Therapeutic efficacy of proton transport inhibitors alone or in combination with cisplatin in triple negative and hormone sensitive breast cancer models

Triple negative breast cancers (TNBCs) are very aggressive and have a poor prognosis due to lack of efficacious therapies. The only effective treatment is chemotherapy that however is frequently hindered by the occurrence of drug resistance. We approached this problem in vitro and in vivo on a triple negative and a hormone sensitive breast cancer cell lines: 4T1 and TS/A. A main defense mechanism of tumors is the extrusion of intracellular protons derived from the metabolic shift to glycolysis, and necessary to maintain an intracellular pH compatible with life. The resulting acidic extracellular milieu bursts the malignant behavior of tumors and impairs chemotherapy. Therefore, we investigated the efficacy of combined therapies that associate cisplatin (Cis) with proton exchanger inhibitors, such as esomeprazole (ESO) and 5-(N-ethyl-N-isopropyl)amiloride (EIPA). Our results demonstrate that in the 4T1 triple negative model the combined therapy Cis plus EIPA is significantly more effective than the other treatments. Instead, in the TS/A tumor the best therapeutic result is obtained with ESO alone. Remarkably, in both 4T1 and TS/A tumors these treatments correlate with increase of CD8+  T lymphocytes and dendritic cells, and a dramatic reduction of M2 macrophages and other suppressor myeloid cells (MDSC) in the tumor infiltrates.

The Synergistic Effects of SHR6390 Combined With Pyrotinib on HER2+/HR+ Breast Cancer

HER2+/HR+ breast cancer is a special molecular type of breast cancer. Existing treatment methods are prone to resistance; “precision treatment” is necessary. Pyrotinib is a pan-her kinase inhibitor that can be used in HER2-positive tumors, while SHR6390 is a CDK4/6 inhibitor that can inhibit ER+ breast cancer cell cycle progression and cancer cell proliferation. In cancer cells, HER2 and CDK4/6 signaling pathways could be nonredundant; co-inhibition of both pathways by combination of SHR6390 and pyrotinib may have synergistic anticancer activity on HER2+/HR+ breast cancer. In this study, we determined the synergy of the two-drug combination and underlying molecular mechanisms. We showed that the combination of SHR6390 and pyrotinib synergistically inhibited the proliferation, migration, and invasion of HER2+/HR+ breast cancer cells in vitro. The combination of two drugs induced G1/S phase arrest and apoptosis in HER2+/HR+ breast cancer cell lines. The combination of two drugs prolonged the time to tumor recurrence in the xenograft model system. By second-generation RNA sequencing technology and enrichment analysis of the pyrotinib-resistant cell line, we found that FOXM1 was associated with induced resistance to HER2-targeted therapy. In HER2+/HR+ breast cancer cell lines, the combination of the two drugs could further reduce FOXM1 phosphorylation, thereby enhancing the antitumor effect to a certain extent. These findings suggest that SHR6390 combination with pyrotinib suppresses the proliferation, migration, and invasion of HER2+/HR+ breast cancers through regulation of FOXM1.

Intratumoral Heterogeneity and Immune Response Indicators to Predict Overall Survival in a Retrospective Study of HER2-Borderline (IHC 2+) Breast Cancer Patients

Breast cancer (BC) categorized as human epidermal growth factor receptor 2 (HER2) borderline [2+ by immunohistochemistry (IHC 2+)] presents challenges for the testing, frequently obscured by intratumoral heterogeneity (ITH). This leads to difficulties in therapy decisions. We aimed to establish prognostic models of overall survival (OS) of these patients, which take into account spatial aspects of ITH and tumor microenvironment by using hexagonal tiling analytics of digital image analysis (DIA). In particular, we assessed the prognostic value of Immunogradient indicators at the tumor–stroma interface zone (IZ) as a feature of antitumor immune response. Surgical excision samples stained for estrogen receptor (ER), progesterone receptor (PR), Ki67, HER2, and CD8 from 275 patients with HER2 IHC 2+ invasive ductal BC were used in the study. DIA outputs were subsampled by HexT for ITH quantification and tumor microenvironment extraction for Immunogradient indicators. Multiple Cox regression revealed HER2 membrane completeness (HER2 MC) (HR: 0.18, p = 0.0007), its spatial entropy (HR: 0.37, p = 0.0341), and ER contrast (HR: 0.21, p = 0.0449) as independent predictors of better OS, with worse OS predicted by pT status (HR: 6.04, p = 0.0014) in the HER2 non-amplified patients. In the HER2-amplified patients, HER2 MC contrast (HR: 0.35, p = 0.0367) and CEP17 copy number (HR: 0.19, p = 0.0035) were independent predictors of better OS along with worse OS predicted by pN status (HR: 4.75, p = 0.0018). In the non-amplified tumors, three Immunogradient indicators provided the independent prognostic value: CD8 density in the tumor aspect of the IZ and CD8 center of mass were associated with better OS (HR: 0.23, p = 0.0079 and 0.14, p = 0.0014, respectively), and CD8 density variance along the tumor edge predicted worse OS (HR: 9.45, p = 0.0002). Combining these three computational indicators of the CD8 cell spatial distribution within the tumor microenvironment augmented prognostic stratification of the patients. In the HER2-amplified group, CD8 cell density in the tumor aspect of the IZ was the only independent immune response feature to predict better OS (HR: 0.22, p = 0.0047). In conclusion, we present novel prognostic models, based on computational ITH and Immunogradient indicators of the IHC biomarkers, in HER2 IHC 2+ BC patients.

Evaluating the Risk of Breast Cancer Recurrence and Metastasis After Adjuvant Tamoxifen Therapy by Integrating Polymorphisms in Cytochrome P450 Genes and Clinicopathological Characteristics

Tamoxifen (TAM) is the most commonly used adjuvant endocrine drug for hormone receptor-positive (HR+) breast cancer patients. However, how to accurately evaluate the risk of breast cancer recurrence and metastasis after adjuvant TAM therapy is still a major concern. In recent years, many studies have shown that the clinical outcomes of TAM-treated breast cancer patients are influenced by the activity of some cytochrome P450 (CYP) enzymes that catalyze the formation of active TAM metabolites like endoxifen and 4-hydroxytamoxifen. In this study, we aimed to first develop and validate an algorithm combining polymorphisms in CYP genes and clinicopathological signatures to identify a subpopulation of breast cancer patients who might benefit most from TAM adjuvant therapy and meanwhile evaluate major risk factors related to TAM resistance. Specifically, a total of 256 patients with invasive breast cancer who received adjuvant endocrine therapy were selected. The genotypes at 10 loci from three TAM metabolism-related CYP genes were detected by time-of-flight mass spectrometry and multiplex long PCR. Combining the 10 loci with nine clinicopathological characteristics, we obtained 19 important features whose association with cancer recurrence was assessed by importance score via random forests. After that, a logistic regression model was trained to calculate TAM risk-of-recurrence score (TAM RORs), which is adopted to assess a patient's risk of recurrence after TAM treatment. The sensitivity and specificity of the model in an independent test cohort were 86.67% and 64.56%, respectively. This study showed that breast cancer patients with high TAM RORs were less sensitive to TAM treatment and manifested more invasive characteristics, whereas those with low TAM RORs were highly sensitive to TAM treatment, and their conditions were stable during the follow-up period. There were some risk factors that had a significant effect on the efficacy of TAM. They were tissue classification (tumor Grade < 2 vs. Grade ≥ 2, p = 2.2e-16), the number of lymph node metastases (Node-Negative vs. Node < 4, p = 5.3e-07; Node < 4 vs. Node ≥ 4, p = 0.003; Node-Negative vs. Node ≥ 4, p = 7.2e-15), and the expression levels of estrogen receptor (ER) and progesterone receptor (PR) (ER < 50% vs. ER ≥ 50%, p = 1.3e-12; PR < 50% vs. PR ≥ 50%, p = 2.6e-08). The really remarkable thing is that different genotypes of CYP2D6*10(C188T) show significant differences in prediction function (CYP2D6*10 CC vs. TT, p < 0.019; CYP2D6*10 CT vs. TT, p < 0.037). There are more than 50% Chinese who have CYP2D6*10 mutation. So the genotype of CYP2D6*10(C188T) should be tested before TAM therapy.

The role of ferroptosis-related genes for overall survival prediction in breast cancer

Background

Ferroptosis is a novel iron‐dependent form of cell death, which is implicated in various diseases including cancers. However, the influence of ferroptosis‐related genes on the prognosis of breast cancer remains unclear.

Methods

RNA sequencing data of 1053 breast cancer tissue samples and 111 normal tissue samples from The Cancer Genome Atlas (TCGA) were analyzed. Expression levels of 259 ferroptosis‐related genes were compared. Gene Ontology (GO) and the Kyoto Gene and Genomic Encyclopedia (KEGG) analyses were conducted on differentially expressed genes. Cox univariate analysis was conducted to explore the potential prognostic biomarkers of breast cancer. Infiltrating immune cell status was assessed.

Results

A total of 66 ferroptosis‐related genes were differentially expressed in breast cancer tissues. The enriched GO terms included Biological Process (mainly included response to oxidative stress, cellular response to chemical stress, multicellular organismal homeostasis, cofactor metabolic process, response to metal ion, response to steroid hormone, cellular response to oxidative stress, transition metal ion homeostasis, iron ion homeostasis, and cellular iron ion homeostasis), Cellular Component (mainly included apical plasma membrane, early endosome, apical part of cell, lipid droplet, basolateral plasma membrane, blood microparticle, clathrin‐coated pit, caveola, astrocyte projection, and pronucleus) and Molecular Function (mainly included iron ion binding, ubiquitin protein ligase binding, oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, oxidoreductase activity, acting on the CH−OH group of donors, NAD or NADP as acceptor, ferric iron binding, aldo−keto reductase (NADP) activity, oxidoreductase activity, acting on single donors with incorporation of molecular oxygen, steroid dehydrogenase activity, alditol:NADP+1−oxidoreductase activity, and alcohol dehydrogenase (NADP+) activity). The enriched KEGG pathway mainly included the HIF‐1 signaling pathway, NOD‐like receptor signaling pathway, ferroptosis, IL‐17 signaling pathway, central carbon metabolism in cancer, PPAR signaling pathway, PD‐L1 expression, and PD‐1 checkpoint pathway in cancer. Among them, 38 ferroptosis‐related genes were significantly associated with the prognosis of breast cancer. The prognostic model was constructed, and breast cancer patients in low‐risk group had a better prognosis. In addition, risk score of ferroptosis prognostic model was negatively correlated with B cells (r = −0.063, p = 0.049), CD8+ T cells (r = −0.083, p = 0.010), CD4+ T cells (r = −0.097, p = 0.002), neutrophils (r = −0.068, p = 0.033), and dendritic cells (r = 0.088, p = 0.006).

Conclusions

The ferroptosis pathway plays a key role in breast cancer. Some differentially expressed ferroptosis‐related genes can be used as prognostic biomarkers for breast cancer.

Comparing Biomarkers for Predicting Pathological Responses to Neoadjuvant Therapy in HER2-Positive Breast Cancer: A Systematic Review and Meta-Analysis

INTRODUCTION

The predictive strength and accuracy of some biomarkers for the pathological complete response (pCR) to neoadjuvant therapy for HER2-positive breast cancer remain unclear. This study aimed to compare the accuracy of the HER2-enriched subtype and the presence of PIK3CA mutations, namely, TILs, HRs, and Ki-67, in predicting the pCR to HER2-positive breast cancer therapy.

METHODS

We screened studies that included pCR predicted by one of the following biomarkers: the HER2-enriched subtype and the presence of PIK3CA mutations, TILs, HRs, or Ki-67. We then calculated the pooled sensitivity, specificity, positive and negative predictive values (PPVs and NPVs, respectively), and positive and negative likelihood ratios (LRs). Summary receiver operating characteristic (SROC) curves and areas under the curve (AUCs) were used to estimate the diagnostic accuracy.

RESULTS

The pooled estimates of sensitivity and specificity for the HER2-enriched subtype and the presence of PIK3CA mutations, namely, TILs, HRs, and Ki-67, were 0.66 and 0.62, 0.85 and 0.27, 0.49 and 0.61, 0.54 and 0.64, and 0.68 and 0.51, respectively. The AUC of the HER2-enriched subtype was significantly higher (0.71) than those for the presence of TILs (0.59, p = 0.003), HRs (0.65, p = 0.003), and Ki-67 (0.62, p = 0.005). The AUC of the HER2-enriched subtype had a tendency to be higher than that of the presence of PIK3CA mutations (0.58, p = 0.220). Moreover, it had relatively high PPV (0.58) and LR+ (1.77), similar NPV (0.73), and low LR- (0.54) compared with the other four biomarkers.

CONCLUSIONS

The HER2-enriched subtype has a moderate breast cancer diagnostic accuracy, which is better than those of the presence of PIK3CA mutations, TILs, HRs, and Ki-67.

Identification of a risk prediction model for clinical prognosis in HER2 positive breast cancer patients

Background New biomarkers are needed to identify different clinical outcomes for HER2+ breast cancer (BC). Methods Differential genes of HER2+ BC were screened based on TCGA database. We used WGCNA to identify the genes related to the survival. Genetic Algorithm was used to structure risk prediction model. The prognostic model was validated in GSE data. Results We constructed a risk prediction model of 6 genes to identify prognosis of HER2+ BC, including CLEC9A, PLD4, PIM1, PTK2B, AKNAD1 and C15orf27. Kaplan-Meier curve showed that the model effectively distinguished the survival of HER2+ BC patients. The multivariate Cox regression suggested that the risk model was an independent predictor for HER2+ BC. Analysis related to immune showed that significant differences in immune infiltration between high- and low-risk groups classified by the prognostic model. Conclusions Our study identified a risk prediction model of 6 genes that could distinguish the prognosis of HER2+ BC.

Nanobody-Based Theranostic Agents for HER2-Positive Breast Cancer: Radiolabeling Strategies

The overexpression of human epidermal growth factor 2 (HER2) in breast cancer (BC) has been associated with a more aggressive tumor subtype, poorer prognosis and shorter overall survival. In this context, the development of HER2-targeted radiotracers is crucial to provide a non-invasive assessment of HER2 expression to select patients for HER2-targeted therapies, monitor response and identify those who become resistant. Antibodies represent ideal candidates for this purpose, as they provide high contrast images for diagnosis and low toxicity in the therapeutic setting. Of those, nanobodies (Nb) are of particular interest considering their favorable kinetics, crossing of relevant biological membranes and intratumoral distribution. The purpose of this review is to highlight the unique characteristics and advantages of Nb-based radiotracers in BC imaging and therapy. Additionally, radiolabeling methods for Nb including direct labeling, indirect labeling via prosthetic group and indirect labeling via complexation will be discussed, reporting advantages and drawbacks. Furthermore, the preclinical to clinical translation of radiolabeled Nbs as promising theranostic agents will be reported.

Novel Nitrogen-Based Chalcone Analogs Provoke Substantial Apoptosis in HER2-Positive Human Breast Cancer Cells via JNK and ERK1/ERK2 Signaling Pathways

Natural chalcones possess antitumor properties and play a role as inducers of apoptosis, antioxidants and cytotoxic compounds. We recently reported that novel nitrogen chalcone-based compounds, which were generated in our lab, have specific effects on triple-negative breast cancer cells. However, the outcome of these two new compounds on human epidermal growth factor receptor 2 (HER2)-positive breast cancer remains nascent. Thus, we herein investigated the effects of these compounds (DK-13 and DK-14) on two HER2-positive breast cancer cell lines, SKBR3 and ZR75. Our data revealed that these compounds inhibit cell proliferation, deregulate cell-cycle progression and significantly induce cell apoptosis in both cell lines. Furthermore, the two chalcone compounds cause a significant reduction in the cell invasion ability of SKBR3 and ZR75 cancer cells. In parallel, we found that DK-13 and DK-14 inhibit colony formation of both cell lines in comparison to their matched controls. On the other hand, we noticed that these two compounds can inhibit angiogenesis in the chorioallantoic membrane model. The molecular pathway analysis of chalcone compounds exposed cells revealed that these compounds inhibit the expression of both JNK1/2/3 and ERK1/2, the major plausible molecular pathways behind these events. Our findings implicate that DK-13 and DK-14 possess effective chemotherapeutic outcomes against HER2-positive breast cancer via the ERK1/2 and JNK1/2/3 signaling pathways.

Dissecting the biological heterogeneity of HER2-positive breast cancer

HER2-positive (HER2+) breast cancer (BC) is a heterogenous and multifaceted disease, with interesting therapeutic implications. First, all intrinsic molecular subtypes can be identified in HER2+ tumors, with the HER2-enriched being the most frequent. Such subtypes do not differ much from their counterparts in HER2-negative disease, apart for the high expression of genes in/near the HER2 amplicon on chromosome 17. Intrinsic subtyping, along with the quantification of ERBB2 mRNA levels, is associated with higher rates of pathologic complete response across neoadjuvant trials of dual HER2 blockade and might help select patients for de-escalation and escalation treatment strategies. Secondly, HER2+ tumors have a broad range of DNA alterations. ERBB2 mutations and alterations in the PI3K/Akt/mTOR pathway are among the most frequent and might predict benefit from potent pan-HER, PI3K and mTOR inhibitors. Moreover, HER2+ tumors are usually infiltrated by lymphocytes. These tumor infiltrating-lymphocytes (TILs) predict response to neoadjuvant anti-HER2-based treatment and exert a prognostic role. PD-L1, detected in ∼42 % of HER2+ BC, might also be useful to define patients responding to novel anti-PD1/PD-L1 immunotherapies. New multiparametric clinicopathologic and genomic tools accounting for this complexity, such as HER2DX, are under development to define more tailored treatment approaches. Finally, HER2-targeted antibody-drug conjugates (ADC) such as trastuzumab deruxtecan might be active in tumors with low expression of HER2. Overall, there is a need to molecularly characterize and develop novel targeted therapies for HER2+ disease.

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Almost 50 % of HER2+ breast cancer (BC) are molecularly HER2-Enriched (HER2-E).

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Most relevant mutations are found in ERBB2 (∼4 %) and PI3K/AKT/mTOR pathway (>30 %).

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Tumor infiltrating lymphocytes are frequent, predictive and prognostic in HER2+ BC.

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HER2 heterogeneity and HER2 low status are gaining therapeutic relevance.

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New treatments need to consider HER2+ molecular and microenvironmental complexity.

Tamoxifen overcomes the trastuzumab-resistance of SK-BR-3 tumorspheres by targeting crosstalk between cytoplasmic estrogen receptor α and the EGFR/HER2 signaling pathway

Since trastuzumab-resistance remains a major obstacle to the successful treatment of HER2-positive breast cancer, a detailed understanding of the mechanisms responsible is required to direct future pharmacotherapeutic strategies. Recently, several studies have indicated that the quiescent natures of cancer stem cells contribute to treatment resistance and tumor recurrence. Thus, in this study, we investigated the mechanism underlying trastuzumab resistance in a quiescent cell population using tumorsphere cultures and explored better therapeutic strategies to overcome trastuzumab resistance in HER2-positive breast cancer patients. We observed that most cells in SK-BR-3 tumorspheres were quiescent, showing the accumulation of cells at the G0/G1 phase as compared to cells in monolayer culture. Furthermore, SK-BR-3 tumorspheres exhibited enhanced EGFR/HER2 signaling, which was incompletely inhibited by trastuzumab, and subsequently led to trastuzumab-resistance. Interestingly, cytoplasmic estrogen receptor α (ERα) expression was markedly elevated in tumorspheres and was associated with enhanced EGFR/HER2 signaling. Accordingly, inhibition of ERα with tamoxifen selectively targeted tumorspheres rather than cells in monolayer culture and overcame trastuzumab resistance in tumorspheres. Taken together, our findings indicate that crosstalk between cytoplasmic ERα and the HER2/EGFR signaling pathway can be considered a novel therapeutic target for quiescent cell populations within HER2-positive breast cancer and that simultaneous inhibition of ER and the EGFR/HER2 pathway may prevent trastuzumab resistance. We hope that these results provide a basis for the use of combinations of tamoxifen and trastuzumab in HER2-positive breast cancer patients.

Overall Survival of CDK4/6-Inhibitor-Based Treatments in Clinically Relevant Subgroups of Metastatic Breast Cancer: Systematic Review and Meta-Analysis

BACKGROUND

Cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitors + endocrine therapy (ET) prolonged progression-free survival as first- or second-line therapy for hormone receptor-positive (HR+)/HER2-negative metastatic breast cancer prognosis. Given the recent publication of overall survival (OS) data for the 3 CDK4/6-inhibitors, we performed a meta-analysis to identify a more precise and reliable benefit from such treatments in specific clinical subgroups.

METHODS

We conducted a systematic literature search to select all available phase II or III randomized clinical trials of CDK4/6-inhibitors + ET reporting OS data in first- or second-line therapy of HR+/HER2-negative pre- or postmenopausal metastatic breast cancer. A random effect model was applied for the analyses. Heterogeneity was assessed with I2statistic. Subgroup analysis was performed to explore the effect of study-level factors. The project was registered in the Open Science Framework database (doi: 10.17605/OSF.IO/TNZQP).

RESULTS

Six studies were included in our analyses (3421 patients). A clear OS benefit was observed in patients without (hazard ratio [HR] = 0.68, 95% confidence interval [CI] = 0.54 to 0.85, I2 = 0.0%) and with visceral involvement (HR = 0.76, 95% CI = 0.65 to 0.89, I2 = 0.0%), with at least 3 metastatic sites (HR = 0.75, 95% CI = 0.60 to 0.94, I2 = 11.6%), in an endocrine-resistant (HR = 0.79, 95% CI = 0.67 to 0.93, I2 = 0.0%) and sensitive subset (HR = 0.73, 95% CI = 0.61 to 0.88, I2 = 0.0%), for younger than 65 years (HR = 0.80, 95% CI = 0.67 to 0.95, I2 = 0.0%) and 65 years or older (HR = 0.71, 95% CI = 0.53 to 0.95, I2 = 44.4%), in postmenopausal (HR = 0.76, 95% CI = 0.67 to 0.86, I2 = 0.0%) and pre- or perimenopausal setting (HR = 0.76, 95% CI = 0.60 to 0.96, I2 = 0.0%) as well as in chemotherapy-naïve patients (HR = 0.72, 95% CI = 0.55 to 0.93, I2 = 0.0%).

CONCLUSIONS

CDK4/6-inhibitors + ET combinations compared with ET alone improve OS independent of age, menopausal status, endocrine sensitiveness, and visceral involvement and should be preferred as upfront therapy instead of endocrine monotherapy.

Current trends in the treatment of HR+/HER2+ breast cancer

Treatment for HR+/HER2+ patients has been debated, as some tumors within this luminal HER2+ subtype behave like luminal A cancers, whereas others behave like non-luminal HER2+ breast cancers. Recent research and clinical trials have revealed that a combination of hormone and targeted anti-HER2 approaches without chemotherapy provides long-term disease control for at least some HR+/HER2+ patients. Novel anti-HER2 therapies, including neratinib and trastuzumab emtansine, and new agents that are effective in HR+ cancers, including the next generation of oral selective estrogen receptor downregulators/degraders and CDK4/6 inhibitors such as palbociclib, are now being evaluated in combination. This review discusses current trials and results from previous studies that will provide the basis for current recommendations on how to treat newly diagnosed patients with HR+/HER2+ disease.