Lapatinib combined with doxorubicin causes dose-dependent cardiotoxicity partially through activating the p38MAPK signaling pathway in zebrafish embryos

Because of its enhanced antitumor efficacy, lapatinib (LAP) is commonly used clinically in combination with the anthracycline drug doxorubicin (DOX) to treat metastatic breast cancer. While it is well recognized that this combination chemotherapy can lead to an increased risk of cardiotoxicity in adult women, its potential cardiotoxicity in the fetus during pregnancy remains understudied. Here, we aimed to examine the combination of LAP chemotherapy and DOX-induced cardiotoxicity in the fetus using a zebrafish embryonic system and investigate the underlying pathologic mechanisms. First, we examined the dose-dependent cardiotoxicity of combined LAP and DOX exposure in zebrafish embryos, which mostly manifested as pericardial edema, bradycardia, cardiac function decline and reduced survival. Second, we revealed that a significant increase in oxidative stress concurrent with activated MAPK signaling, as indicated by increased protein expression of phosphorylated p38 and Jnk, was a notable pathophysiological event after combined LAP and DOX exposure. Third, we showed that inhibiting MAPK signaling by pharmacological treatment with the p38MAPK inhibitor SB203580 or genetic ablation of the map2k6 gene could significantly alleviate combined LAP and DOX exposure-induced cardiotoxicity. Thus, we provided both pharmacologic and genetic evidence to suggest that inhibiting MAPK signaling could exert cardioprotective effects. These findings have implications for understanding the potential cardiotoxicity induced by LAP and DOX combinational chemotherapy in the fetus during pregnancy, which could be leveraged for the development of new therapeutic strategies.

Unveiling the Immune Microenvironment's Role in Breast Cancer: A Glimpse into Promising Frontiers

Breast cancer (BC), one of the most widespread and devastating diseases affecting women worldwide, presents a significant public health challenge. This review explores the emerging frontiers of research focused on deciphering the intricate interplay between BC cells and the immune microenvironment. Understanding the role of the immune system in BC is critical as it holds promise for novel therapeutic approaches and precision medicine strategies. This review delves into the current literature regarding the immune microenvironment's contribution to BC initiation, progression, and metastasis. It examines the complex mechanisms by which BC cells interact with various immune cell populations, including tumor-infiltrating lymphocytes (TILs) and tumor-associated macrophages (TAMs). Furthermore, this review highlights the impact of immune-related factors, such as cytokines and immune checkpoint molecules. Additionally, this comprehensive analysis sheds light on the potential biomarkers associated with the immune response in BC, enabling early diagnosis and prognostic assessment. The therapeutic implications of targeting the immune microenvironment are also explored, encompassing immunotherapeutic strategies and combination therapies to enhance treatment efficacy. The significance of this review lies in its potential to pave the way for novel therapeutic interventions, providing clinicians and researchers with essential knowledge to design targeted and personalized treatment regimens for BC patients.

Risk-Based Therapeutic Strategies for HER2-Positive Early Breast Cancer: A Consensus Paper

Breast cancer represents the most commonly diagnosed neoplasm worldwide and the HER2-positive subtype accounts for nearly 1 in 5 breast cancers. The majority of patients with breast cancer present with an early-stage disease upon diagnosis, which is thus susceptible to virtually curative treatment strategies. For a stage, I T1a/b N0 HER2-positive disease, upfront surgery followed by adjuvant therapy is the preferred approach. However, there is some uncertainty regarding the appropriate management of stage cT1c cN0, as both the neoadjuvant approach and upfront surgery have been proven to be feasible therapeutic options. The aim of this Delphi consensus was to define the best strategies for the treatment of early HER2-positive breast cancer. This work may help clinicians in the management of early HER2-positive breast cancer.

UK recommendations for HER2 assessment in breast cancer: an update

The last UK breast cancer (BC) human epidermal growth factor receptor 2 (HER2) testing guideline recommendations were published in 2015. Since then, new data and therapeutic strategies have emerged. The American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) published a focused update in 2018 that reclassified in situ hybridisation (ISH) Group 2 (immunohistochemistry (IHC) score 2+and HER2/chromosome enumeration probe 17 (CEP17) ratio ≥2.0 and HER2 copy number <4.0 signals/cell), as well as addressed other concerns raised by previous guidelines. The present article further refines UK guidelines, with specific attention to definitions of HER2 status focusing on eight key areas: (1) HER2 equivocal (IHC 2+) and assignment of the ASCO/CAP ISH group 2 tumours; (2) the definition of the group of BCs with low IHC scores for HER2 with emphasis on the distinction between IHC score 1+ (HER2-Low) from HER2 IHC score 0 (HER2 negative); (3) reporting cases showing HER2 heterogeneity; (4) HER2 testing in specific settings, including on cytological material; (5) repeat HER2 testing, (6) HER2 testing turnaround time targets; (7) the potential role of next generation sequencing and other diagnostic molecular assays for routine testing of HER2 status in BC and (8) use of image analysis to score HER2 IHC. The two tiered system of HER2 assessment remains unchanged, with first line IHC and then ISH limited to IHC equivocal cases (IHC score 2+) but emerging data on the relationship between IHC scores and levels of response to anti-HER2 therapy are considered. Here, we present the latest UK recommendations for HER2 status evaluation in BC, and where relevant, the differences from other published guidelines.

Review of the status of neoadjuvant therapy in HER2-positive breast cancer

Purpose

The development of human epidermal growth factor receptor 2 (HER2)-directed therapies has revolutionized the treatment of HER2-positive breast cancer. The aim of this article is to review the continually evolving treatment strategies in the neoadjuvant setting of HER2-positive breast cancer, as well as the current challenges and future perspectives.

Methods

Searches were undertaken on PubMed and Clinicaltrials.gov for relevant publications and trials.

Findings

The current standard of care in high-risk HER2-positive breast cancer is to combine chemotherapy with dual anti-HER2 therapy, for a synergistic anti-tumor effect. We discuss the pivotal trials which led to the adoption of this approach, as well as the benefit of these neoadjuvant strategies for guiding appropriate adjuvant therapy. De-escalation strategies are currently being investigated to avoid over treatment, and aim to safely reduce chemotherapy, while optimizing HER2-targeted therapies. The development and validation of a reliable biomarker is essential to enable these de-escalation strategies and personalization of treatment. In addition, promising novel therapies are currently being explored to further improve outcomes in HER2-positive breast cancer.

Using the HER2/CEP17 FISH Ratio to Predict Pathologic Complete Response Following Neoadjuvant Anti-HER2 Doublet Therapy in HER2+ Breast Cancer

BACKGROUND

Clinical trials of HER2-directed therapy that omit neoadjuvant conventional chemotherapy for HER+ breast cancer demonstrate that a subset of patients still obtains a pCR. Identifying tumor characteristics which predict pCR may help select patients for de-escalated neoadjuvant dual HER2-targeted treatment without chemotherapy. This is the first study evaluating the HER2/CEP17 ratio by FISH as a biomarker to predict pCR among patients who received neoadjuvant anti-HER2 regimens without chemotherapy.

PATIENTS AND METHODS

Data from patients with locally advanced HER2+ breast cancer who received neoadjuvant dual HER2-targeted therapy without conventional chemotherapy from a single center was retrospectively reviewed. All patients were enrolled in one of 3 clinical trials evaluating chemotherapy de-escalation. Logistic regression modeling assessed for a relationship between the HER2/CEP17 FISH ratio obtained from baseline tissue biopsy and pCR based on pathology at the time of definitive breast surgery following neoadjuvant treatment.

RESULTS

Following neoadjuvant treatment with dual HER2-targeted therapies in 56 patients, the probability of pCR was 73% among patients with a HER2 ratio of 13.1 compared to a probability of 38% among patients with HER2 ratio of 5.5 (OR 4.14, 95% CI 1.44-11.89; P = .012). This positive association persisted after controlling for different treatment regimens administered (OR 2.87, 95% CI 0.9-9.18, P = .020).

CONCLUSIONS

These data found a positive association between the HER2/CEP17 FISH ratio and pCR following neoadjuvant dual HER2-targeted therapy without chemotherapy. Larger prospective studies are needed to validate the HER2 ratio as a biomarker to select patients for neoadjuvant dual anti-HER2 therapy without chemotherapy.

Three-year disease-free survival in randomized trials of neoadjuvant chemotherapy and HER2-targeted therapy in breast cancer: A meta-analysis

BACKGROUND

Outcomes for breast cancer patients with residual disease (RD) after neoadjuvant chemotherapy (NACT) and HER2-targeted therapy may be better than anticipated leading to a smaller absolute benefit of adjuvant trastuzumab emtansine (T-DM1). Therefore, accurate estimates of 3-year disease-free survival (DFS) can aid in treatment planning.

METHODS

We reviewed randomized trials of NACT and HER2-targeted therapy in breast cancer (excluding T-DM1) and calculated mean 3-year DFS weighted by study sample size. Meta-regression comprising linear regression weighted by sample size (mixed-effects) was performed to explore associations between 3-year DFS and year of accrual and trial-level patient, disease, and treatment factors. Data were reported quantitatively irrespective of statistical significance.

RESULTS

Eleven studies (N = 3581) were included in the primary analysis. The mean 3-year DFS for patients with RD was 79.7% (95% CI 77.4-80.9). This was higher for trials completing accrual after 2010 [83% (95% CI 79.3-86.3)] and for those receiving dual HER2 targeted therapy [83.4% (95% CI 79.2-87.7]. Better outcomes for ER positivity, later accrual and dual Her-2 targeted therapy were confirmed in meta-regression. Negative quantitative significance was observed for larger clinical tumor size and nodal involvement.

CONCLUSIONS

The 3-year DFS for patients with RD has improved over time possibly due to dual HER2 targeted therapy. This will reduce the absolute benefit of adjuvant T-DM1 in this group of patients.

Lapatinib and lapatinib plus trastuzumab therapy versus trastuzumab therapy for HER2 positive breast cancer patients: an updated systematic review and meta-analysis

INTRODUCTION

Trastuzumab, as the gold standard for HER2-positive BC treatment, was the first-line HER2 targeted drug. However, some studies reported patients benefited more from lapatinib and lapatinib plus trastuzumab therapy than standard trastuzumab therapy. This study presents an update of a systematic review and meta-analysis involving comparison of lapatinib and lapatinib plus trastuzumab therapy versus trastuzumab therapy.

AIM

We determined whether trastuzumab plus lapatinib or lapatinib therapy is not inferior to trastuzumab therapy in HER2-positive breast cancer patients.

METHODS

Relevant trials were searched in CNKI, Wanfang, VIP, Sinomed, PubMed, Embase, and Cochrane CENTRAL databases from inception until October 25, 2021. Primary outcomes were OS, DFS/EFS, and PFS while secondary outcomes were pCR (ypT0/is ypN0), pCR (ypT0/is ypN0/+), ORR, DCR, rate of BCS, RFS, cardiac toxicities, and other toxicities.

RESULTS

Thirteen randomized controlled trials were included in this study. Trastuzumab combined with lapatinib therapy was found to be superior to standard trastuzumab therapy alone with regard to overall survival, disease-free survival/event-free survival, pathologic complete response (ypT0/is ypN0), pathologic complete response (ypT0/is ypN0/+), recurrence-free survival, higher incidences of diarrhea, and rash/skin toxicity. Lapatinib therapy was established to be inferior to trastuzumab therapy in overall survival, progression-free survival, disease-free survival/event-free survival, pathologic complete response (ypT0/is ypN0) and pathologic complete response (ypT0/is ypN0/+), diarrhea, and rash/skin toxicity and had a low incidence of left ventricular ejection fraction decline.

CONCLUSIONS

The efficacy of trastuzumab combined with lapatinib therapy is superior to standard trastuzumab therapy alone; however, it has more non-cardiac grade III/IV toxicities. Moreover, the efficacy of lapatinib therapy is inferior to that of standard trastuzumab therapy alone.

Predictive Biomarkers of Response to Neoadjuvant Chemotherapy in Breast Cancer: Current and Future Perspectives for Precision Medicine

Pathological complete response (pCR) after neoadjuvant chemotherapy in patients with early breast cancer is correlated with better survival. Meanwhile, an expanding arsenal of post-neoadjuvant treatment strategies have proven beneficial in the absence of pCR, leading to an increased use of neoadjuvant systemic therapy in patients with early breast cancer and the search for predictive biomarkers of response. The better prediction of response to neoadjuvant chemotherapy could enable the escalation or de-escalation of neoadjuvant treatment strategies, with the ultimate goal of improving the clinical management of early breast cancer. Clinico-pathological prognostic factors are currently used to estimate the potential benefit of neoadjuvant systemic treatment but are not accurate enough to allow for personalized response prediction. Other factors have recently been proposed but are not yet implementable in daily clinical practice or remain of limited utility due to the intertumoral heterogeneity of breast cancer. In this review, we describe the current knowledge about predictive factors for response to neoadjuvant chemotherapy in breast cancer patients and highlight the future perspectives that could lead to the better prediction of response, focusing on the current biomarkers used for clinical decision making and the different gene signatures that have recently been proposed for patient stratification and the prediction of response to therapies. We also discuss the intratumoral phenotypic heterogeneity in breast cancers as well as the emerging techniques and relevant pre-clinical models that could integrate this biological factor currently limiting the reliable prediction of response to neoadjuvant systemic therapy.

CuS@BSA-NB2 Nanoparticles for HER2-Targeted Photothermal Therapy

Breast cancer is characterized by the uncontrolled proliferation of breast epithelial cells under the action of a variety of carcinogens. Although HER2-inhibitors were currently applied for HER2-positive breast cancer patients, they didn't work for patients with resistance to HER2-targeted anti-cancer drugs. In this work, we prepared novel CuS@BSA-NB2 nanoparticles (NPs) for breast cancer photothermal therapy (PTT). The NPs had good biocompatibility due to the Bovine Serum Albumin (BSA) encapsulating and excellent targeting to HER2 because of nanobody 2 (NB2). Under 808 nm laser irradiation, CuS@BSA-NB2 NPs had high photothermal conversion efficiency and photothermal stability. Meanwhile, we constructed a stable cell line of MDA-MB-231/HER2 with a high expression of HER2 protein. Immunofluorescence and ICP-MS assays showed that CuS@BSA-NB2 NPs can be specifically enriched and be ingested in MDA-MB-231/HER2 cells. Furthermore, CuS@BSA-NB2 NPs had shown a more significant photothermal treatment effect than CuS@BSA under certain treatment conditions for MDA-MB-231/HER2. In addition, the cytotoxicity assay demonstrated that CuS@BSA-NB2 NPs had a low toxicity for MDA-MB-231/HER2 cells. The above results suggested that CuS@BSA-NB2 NPs were great photothermal therapeutic agents to reduce the malignant proliferation of breast epithelial cells and have potential for breast cancer therapy.

Neoadjuvant Treatment with HER2-Targeted Therapies in HER2-Positive Breast Cancer: A Systematic Review and Network Meta-Analysis

Simple Summary

Human epidermal growth factor receptor 2 (HER2)-positive breast cancer causes more aggressive progression of disease and poorer outcomes for patients. HER2-targeted medicines used as neoadjuvant systemic therapy could improve clinical outcomes in early-stage or locally advanced breast cancer patients. The purpose of this systematic review and network meta-analysis was to identify the neoadjuvant anti-HER2 therapy with the best balance between efficacy and safety. We found that trastuzumab emtansine + pertuzumab + chemotherapy had a high pathologic complete response with a low risk of adverse events compared to other neoadjuvant anti-HER2 regimens, while the pertuzumab + trastuzumab + chemotherapy regimen showed the highest disease-free survival. However, further trial data on neoadjuvant regimens with trastuzumab emtansine are needed to confirm these findings.

Abstract

This systematic review aimed to identify neoadjuvant anti-human epidermal growth factor receptor 2 (HER2) therapies with the best balance between efficacy and safety. Methods: A network meta-analysis was applied to estimate the risk ratios along with 95% confidence intervals (CIs) for pathological complete response (pCR) and serious adverse events (SAE). A mixed-effect parametric survival analysis was conducted to assess the disease-free survival (DFS) between treatments. Results: Twenty-one RCTs with eleven regimens of neoadjuvant anti-HER2 therapy (i.e., trastuzumab + chemotherapy (TC), lapatinib + chemotherapy (LC), pertuzumab + chemotherapy (PC), pertuzumab + trastuzumab (PT), trastuzumab emtansine + pertuzumab (T-DM1P), pertuzumab + trastuzumab + chemotherapy (PTC), lapatinib + trastuzumab + chemotherapy (LTC), trastuzumab emtansine + lapatinib + chemotherapy (T-DM1LC), trastuzumab emtansine + pertuzumab + chemotherapy(T-DM1PC), PTC followed by T-DM1P (PTC_T-DM1P), and trastuzumab emtansine (T-DM1)) and chemotherapy alone were included. When compared to TC, only PTC had a significantly higher DFS with a hazard ratio (95% CI) of 0.54 (0.32–0.91). The surface under the cumulative ranking curve (SUCRA) suggested that T-DM1LC (91.9%) was ranked first in achieving pCR, followed by the PTC_T-DM1P (90.5%), PTC (74.8%), and T-DM1PC (73.5%) regimens. For SAEs, LTC, LC, and T-DM1LC presented with the highest risks (SUCRA = 10.7%, 16.8%, and 20.8%), while PT (99.2%), T-DM1P (88%), and T-DM1 (83.9%) were the safest regimens. The T-DM1PC (73.5% vs. 71.6%), T-DM1 (70.5% vs. 83.9%), and PTC_T-DM1P (90.5% vs. 47.3%) regimens offered the optimal balance between pCR and SAE. Conclusions: The T-DM1PC, T-DM1, and PTC_T-DM1P regimens had the optimal balance between efficacy and safety, while DFS was highest for the PTC regimen. However, these results were based on a small number of studies, and additional RCTs assessing the efficacy of regimens with T-DM1 are still needed to confirm these findings.

Evaluation of pathological complete response as surrogate endpoint in neoadjuvant randomised clinical trials of early stage breast cancer: systematic review and meta-analysis

OBJECTIVE

To evaluate pathological complete response as a surrogate endpoint for disease-free survival and overall survival in regulatory neoadjuvant trials of early stage breast cancer.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, and Scopus to 1 December 2020.

ELIGIBILITY CRITERIA FOR STUDY SELECTION

Randomised clinical trials that tested neoadjuvant chemotherapy given alone or combined with other treatments, including anti-human epidermal growth factor 2 (anti-HER2) drugs, targeted treatments, antivascular agents, bisphosphonates, and immune checkpoint inhibitors.

DATA EXTRACTION AND SYNTHESIS

Trial level associations between the surrogate endpoint pathological complete response and disease-free survival and overall survival.

METHODS

A weighted regression analysis was performed on log transformed treatment effect estimates (hazard ratio for disease-free survival and overall survival and relative risk for pathological complete response), and the coefficient of determination (R2) was used to quantify the association. The secondary objective was to explore heterogeneity of results in preplanned subgroups analysis, stratifying trials according treatment type in the experimental arm, definition used for pathological complete response (breast and lymph nodes v breast only), and biological features of the disease (HER2 positive or triple negative breast cancer). The surrogate threshold effect was also evaluated, indicating the minimum value of the relative risk for pathological complete response necessary to confidently predict a non-null effect on hazard ratio for disease-free survival or overall survival.

RESULTS

54 randomised clinical trials comprising a total of 32 611 patients were included in the analysis. A weak association was observed between the log(relative risk) for pathological complete response and log(hazard ratio) for both disease-free survival (R2=0.14, 95% confidence interval 0.00 to 0.29) and overall survival (R2 =0.08, 0.00 to 0.22). Similar results were found across all subgroups evaluated, independently of the definition used for pathological complete response, treatment type in the experimental arm, and biological features of the disease. The surrogate threshold effect was 5.19 for disease-free survival but was not estimable for overall survival. Consistent results were confirmed in three sensitivity analyses: excluding small trials (<200 patients enrolled), excluding trials with short median follow-up (<24 months), and replacing the relative risk for pathological complete response with the absolute difference of pathological complete response rates between treatment arms.

CONCLUSION

A lack of surrogacy of pathological complete response was identified at trial level for both disease-free survival and overall survival. The findings suggest that pathological complete response should not be used as primary endpoint in regulatory neoadjuvant trials of early stage breast cancer.

Targeting HER2 in Breast Cancer: Latest Developments on Treatment Sequencing and the Introduction of Biosimilars

Approximately 20% of all breast cancers overexpress the human epidermal growth factor receptor 2 (HER2). Targeting breast cancer through this vital oncogenic protein has been a major step towards improved patient outcomes. Today, several anti-HER2 agents are in clinical use including: the monoclonal antibodies trastuzumab and pertuzumab; the small molecule inhibitors lapatinib, neratinib, and tucatinib; and the antibody-drug conjugates ado-trastuzumab emtansine and trastuzumab deruxtecan, in some jurisdictions. In addition, several trastuzumab biosimilars have recently been granted regulatory approval in North America and the EU, and are enhancing patient access to HER2-directed therapy. The various agents differ greatly in their side-effect profiles and approved indications, from neoadjuvant and adjuvant use in early disease, to first- and later-line use in metastatic disease. This review discusses the current treatment recommendations for the use of anti-HER2 agents alone and in combination, examines the latest advances in HER2-targeted drugs and how they may be best applied in clinical practice, and provides guidance on optimal sequencing of the growing array of therapeutic options for HER2-positive breast cancer.

Retrospective observational study of HER2 immunohistochemistry in borderline breast cancer patients undergoing neoadjuvant therapy, with an emphasis on Group 2 (HER2/CEP17 ratio ≥2.0, HER2 copy number <4.0 signals/cell) cases

BACKGROUND

The ASCO/CAP guidance on HER2 testing in breast cancer (BC) has recently changed. Group 2 tumours with immunohistochemistry score 2+ and HER2/CEP17 ratio ≥2.0 and HER2 copy number <4.0 signals/cell were re-classified as HER2 negative. This study aims to examine the response of Group 2 tumours to neoadjuvant chemotherapy (NACT).

METHODS

749 BC cases were identified from 11 institutions. The association between HER2 groups and pathological complete response (pCR) was assessed.

RESULTS

54% of immunohistochemistry HER2 positive (score 3+) BCs showed pCR, compared to 19% of immunohistochemistry 2+ FISH amplified cases. 27% of Group 2 treated with HER2 targeted therapy achieved pCR, compared to 19 and 11% in the combined Groups 1 + 3 and Groups 4 + 5, respectively. No difference in pCR rates was identified between Group 2 and Group 1 or combined Groups 1 + 3. However, Group 2 response rate was higher than Groups 4 + 5 (p = 0.017).

CONCLUSION

No difference in pCR was detected in tumours with a HER2/CEP17 ratio ≥2.0 and a HER2 score 2+ by IHC when stratified by HER2 gene copy number. Our data suggest that ASCO/CAP HER2 Group 2 carcinomas should be evaluated further with respect to eligibility for HER2 targeted therapy.

Treatment outcomes among human epidermal growth factor receptor 2 positive breast cancer patients: A systematic review

BACKGROUND

The incidence of human epidermal growth factor receptor 2 (HER 2) positive breast cancers is rapidly rising worldwide. Although there have been many studies on HER 2 breast cancer treatment and management in recent years, there is a lack of comprehensive reports on the treatment outcomes and disparities within the available literature. Hence, this review aimed to determine the treatment outcomes and their associated factors among patients with HER2-positive breast cancer.

METHODS

A computer-based systematic literature search was conducted using PubMed, EMBASE, and Google scholar databases of articles published from 2000 to 2020. The following key terms (HER 2 positive breast cancer, predictor, determinant, associated factor) and Medical Subject Headings (MeSH) terms (breast neoplasms, treatment outcome, and risk factors) were used to search the English language published articles.

RESULTS

In most studies, trastuzumab was the most commonly used treatment regimen used in combination with chemotherapeutic agents. Generally, most of the studies (15 studies) showed that the overall survival outcome was relatively higher after treatment among HER2 positive breast cancer patients. Nonetheless, two studies showed that the absence of significant change in the overall survival despite adequate treatment was given to the study participants. In addition, three studies demonstrated a partial response after treating HER2-positive breast cancer patients.

CONCLUSION

Generally, the overall survival outcome was relatively higher after treatment among HER2 positive breast cancer patients. The addition of trastuzumab in most of the studies has shown improvement in the overall survival and the disease-free survival rate of the study patients.

Combining Neratinib with CDK4/6, mTOR, and MEK Inhibitors in Models of HER2-positive Cancer

PURPOSE

Neratinib is an irreversible, pan-HER tyrosine kinase inhibitor that is FDA approved for HER2-overexpressing/amplified (HER2+) breast cancer. In this preclinical study, we explored the efficacy of neratinib in combination with inhibitors of downstream signaling in HER2+ cancers in vitro and in vivo.

EXPERIMENTAL DESIGN

Cell viability, colony formation assays, and Western blotting were used to determine the effect of neratinib in vitro. In vivo efficacy was assessed with patient-derived xenografts (PDX): two breast, two colorectal, and one esophageal cancer (with HER2 mutations). Four PDXs were derived from patients who received previous HER2-targeted therapy. Proteomics were assessed through reverse phase protein arrays and network-level adaptive responses were assessed through Target Score algorithm.

RESULTS

In HER2+ breast cancer cells, neratinib was synergistic with multiple agents, including mTOR inhibitors everolimus and sapanisertib, MEK inhibitor trametinib, CDK4/6 inhibitor palbociclib, and PI3Kα inhibitor alpelisib. We tested efficacy of neratinib with everolimus, trametinib, or palbociclib in five HER2+ PDXs. Neratinib combined with everolimus or trametinib led to a 100% increase in median event-free survival (EFS; tumor doubling time) in 25% (1/4) and 60% (3/5) of models, respectively, while neratinib with palbociclib increased EFS in all five models. Network analysis of adaptive responses demonstrated upregulation of EGFR and HER2 signaling in response to CDK4/6, mTOR, and MEK inhibition, possibly providing an explanation for the observed synergies with neratinib.

CONCLUSIONS

Taken together, our results provide strong preclinical evidence for combining neratinib with CDK4/6, mTOR, and MEK inhibitors for the treatment of HER2+ cancer.

Update on systemic treatment for newly diagnosed inflammatory breast cancer

Background

Inflammatory breast cancer (IBC) is a rare and aggressive disease, accounting for 2-4% of new cases of breast cancer. Owing to its aggressive nature, IBC represent approximately 8-10% of breast cancer deaths. Management of IBC requires a multidisciplinary team for decision-making involving a composite of systemic treatment, surgery, and radiation, or "Trimodality Treatment." Because of the rarity of the disease, systemic therapy of IBC traditionally has been extrapolated from non-IBC clinical trials.

Aim of Review

The purpose of this review is to provide an overview of the development of systemic treatment of IBC from the past to the present by focusing on IBC clinical trials, including chemotherapy and targeted therapies.

Key Scientific Concepts of Review

We discuss their effects on pathologic complete response (pCR) and survival outcomes, the predictive markers, and the adverse events of these therapies. Further, we summarized the current standard treatment stratified by molecular subtypes based on clinical data. Finally, we discuss the future trend of systemic therapy, including immunotherapy and ongoing IBC clinical trials.

Dual- versus single-agent HER2 inhibition and incidence of intracranial metastatic disease: a systematic review and meta-analysis

Observational studies have suggested that HER2 inhibition with trastuzumab may be associated with an increased incidence of intracranial metastatic disease (IMD) due to its ability to prolong survival. We hypothesized that prolonged survival associated with dual-agent HER2 inhibition may be associated with an even higher incidence of IMD. This study pooled estimates of IMD incidence and survival among patients with HER2-positive breast cancer receiving dual- versus single-agent HER2 targeted therapy, as well as trastuzumab versus chemotherapy, observation, or another HER2-targeted agent. We searched PubMed, EMBASE, and CENTRAL from inception to 25 March 2020. We included randomized controlled trials that reported IMD incidence for patients with HER2-positive breast cancer receiving trastuzumab as the experimental or control arm irrespective of disease stage. Among 465 records identified, 19 randomized controlled trials (32,572 patients) were included. Meta-analysis of four studies showed that dual HER2-targeted therapy was associated with improved overall survival (HR 0.76; 95% CI, 0.66–0.87) and progression-free survival (HR 0.77; 95% CI, 0.68–0.87) compared to single HER2-targeted therapy, but the risk of IMD was similar (RR 1.03; 95% CI, 0.83–1.27). Our study challenges the hypothesis that prolonged survival afforded by improved extracranial disease control is associated with increased IMD incidence.

Neoadjuvant Chemotherapy, Endocrine Therapy, and Targeted Therapy for Breast Cancer: ASCO Guideline

PURPOSE

To develop guideline recommendations concerning optimal neoadjuvant therapy for breast cancer.

METHODS

ASCO convened an Expert Panel to conduct a systematic review of the literature on neoadjuvant therapy for breast cancer and provide recommended care options.

RESULTS

A total of 41 articles met eligibility criteria and form the evidentiary basis for the guideline recommendations.

RECOMMENDATIONS

Patients undergoing neoadjuvant therapy should be managed by a multidisciplinary care team. Appropriate candidates for neoadjuvant therapy include patients with inflammatory breast cancer and those in whom residual disease may prompt a change in therapy. Neoadjuvant therapy can also be used to reduce the extent of local therapy or reduce delays in initiating therapy. Although tumor histology, grade, stage, and estrogen, progesterone, and human epidermal growth factor receptor 2 (HER2) expression should routinely be used to guide clinical decisions, there is insufficient evidence to support the use of other markers or genomic profiles. Patients with triple-negative breast cancer (TNBC) who have clinically node-positive and/or at least T1c disease should be offered an anthracycline- and taxane-containing regimen; those with cT1a or cT1bN0 TNBC should not routinely be offered neoadjuvant therapy. Carboplatin may be offered to patients with TNBC to increase pathologic complete response. There is currently insufficient evidence to support adding immune checkpoint inhibitors to standard chemotherapy. In patients with hormone receptor (HR)-positive (HR-positive), HER2-negative tumors, neoadjuvant chemotherapy can be used when a treatment decision can be made without surgical information. Among postmenopausal patients with HR-positive, HER2-negative disease, hormone therapy can be used to downstage disease. Patients with node-positive or high-risk node-negative, HER2-positive disease should be offered neoadjuvant therapy in combination with anti-HER2-positive therapy. Patients with T1aN0 and T1bN0, HER2-positive disease should not be routinely offered neoadjuvant therapy.Additional information is available at www.asco.org/breast-cancer-guidelines.

Therapeutic Strategies for the Management of Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Positive (HR+/HER2+) Breast Cancer: A Review of the Current Literature

Enormous advances have been made in the understanding and treatment of human epidermal growth factor receptor 2-positive breast cancer (HER2+ BC) in the last 30 years that have resulted in survival gains for affected patients. A growing body of evidence suggests that hormone receptor-positive (HR+)/HER2+ BC and HR-negative (HR-)/HER2+ BC are biologically different, with complex molecular bidirectional crosstalk between the estrogen receptor and HER2 pathway potentially affecting sensitivity to both HER2-targeted and endocrine therapy in patients with HR+/HER2+ BC. Subgroup analyses from trials enrolling patients with HER2+ BC and the results of clinical trials specifically designed to evaluate therapy in patients with HR+/HER2+ BC are helping to guide treatment decisions. In this context, encouraging results with strategies aimed at delaying or reversing drug resistance, including extended adjuvant therapy and the addition of drugs targeting alternative pathways, such as cyclin-dependent kinase (CDK) 4 and 6 inhibitors, have recently emerged. We have reached the point where tailoring the treatment according to risk and biology has become the paradigm in early BC. However, further clinical trials are needed that integrate translational research principles and identify and consider specific patient subgroups and biomarkers.

Early HER2-Positive Breast Cancer: Current Treatment and Novel Approaches

Background

Trastuzumab significantly improves outcomes in early HER2-positive breast cancer, irrespectively of any prognostic or predictive factors. Unfortunately, about a quarter of patients receiving neoadjuvant trastuzumab experience disease recurrence, revealing the unquestionable need for further improvement of treatment outcomes.

Summary

Adding HER2 blockade to adjuvant trastuzumab with pertuzumab and neratinib improves invasive disease-free survival (IDFS), particularly for those at highest risk of recurrence. A shift toward a neoadjuvant strategy for patients with a higher risk of recurrence could result in further treatment optimization. For patients without a pathological complete response (pCR) after the neoadjuvant part of the therapy, a switch to adjuvant trastuzumab emtansine significantly improves IDFS and distant recurrence-free survival and shows a trend towards improved overall survival (OS). On the other hand, for low-risk patients, chemotherapy deescalation should be strongly considered with the use of trastuzumab monotherapy as an anti-HER2 backbone.

Key Messages

Neoadjuvant therapy should be offered for a significant proportion of HER2-positive early breast cancer patients with a higher risk of recurrence. Postneoadjuvant treatment should be tailored according to the initial stage of disease and the response to neoadjuvant treatment.

Breast Cancer: A Molecularly Heterogenous Disease Needing Subtype-Specific Treatments

Breast cancer is the most commonly occurring cancer in women. There were over two-million new cases in world in 2018. It is the second leading cause of death from cancer in western countries. At the molecular level, breast cancer is a heterogeneous disease, which is characterized by high genomic instability evidenced by somatic gene mutations, copy number alterations, and chromosome structural rearrangements. The genomic instability is caused by defects in DNA damage repair, transcription, DNA replication, telomere maintenance and mitotic chromosome segregation. According to molecular features, breast cancers are subdivided in subtypes, according to activation of hormone receptors (estrogen receptor and progesterone receptor), of human epidermal growth factors receptor 2 (HER2), and or BRCA mutations. In-depth analyses of the molecular features of primary and metastatic breast cancer have shown the great heterogeneity of genetic alterations and their clonal evolution during disease development. These studies have contributed to identify a repertoire of numerous disease-causing genes that are altered through different mutational processes. While early-stage breast cancer is a curable disease in about 70% of patients, advanced breast cancer is largely incurable. However, molecular studies have contributed to develop new therapeutic approaches targeting HER2, CDK4/6, PI3K, or involving poly(ADP-ribose) polymerase inhibitors for BRCA mutation carriers and immunotherapy.

Complement Signals Determine Opposite Effects of B Cells in Chemotherapy-Induced Immunity

Understanding molecular mechanisms that dictate B cell diversity is important for targeting B cells as anti-cancer treatment. Through the single-cell dissection of B cell heterogeneity in longitudinal samples of patients with breast cancer before and after neoadjuvant chemotherapy, we revealed that an ICOSL⁺ B cell subset emerges after chemotherapy. Using three immunocompetent mouse models, we recapitulated the subset switch of human tumor-infiltrating B cells during chemotherapy. By employing B-cell-specific deletion mice, we showed that ICOSL in B cells boosts anti-tumor immunity by enhancing the effector to regulatory T cell ratio. The signature of ICOSL⁺ B cells is imprinted by complement-CR2 signaling, which is triggered by immunogenic cell death. Moreover, we identified that CD55, a complement inhibitory protein, determines the opposite roles of B cells in chemotherapy. Collectively, we demonstrated a critical role of the B cell subset switch in chemotherapy response, which has implications in designing novel anti-cancer therapies. VIDEO ABSTRACT.

Phase II trial of eribulin in patients who do not achieve pathologic complete response (pCR) following neoadjuvant chemotherapy

PURPOSE

Women with residual invasive breast cancer at the primary site or axillary lymph nodes following neoadjuvant chemotherapy have a high risk of recurrence. Eribulin improves survival in patients with metastatic breast cancer who progress after anthracycline and taxane therapy. This phase 2 trial assessed the efficacy of postoperative eribulin in breast cancer patients who did not achieve a pCR following standard neoadjuvant chemotherapy.

METHODS

Women with localized breast cancer who had residual invasive cancer following ≥ 4 cycles of standard anthracycline and/or taxane-containing neoadjuvant chemotherapy received adjuvant eribulin treatment. HER2-positive patients also received trastuzumab for 1 year. Adjuvant hormonal therapy and locoregional radiotherapy were administered as per institutional guidelines. Primary endpoint was the 2-year DFS rate. Three patient cohorts were analyzed: TNBC (Cohort A), HR+/HER2- (Cohort B), and HER2+ (Cohort C).

RESULTS

One hundred twenty-six patients (Cohort A-53, Cohort B-42, and Cohort C-31) were enrolled. Neoadjuvant chemotherapy included a taxane and an anthracycline in 70%. Eribulin was well tolerated; 84% of patients received the planned 6 cycles. After a median follow-up of 28 months, the 24-month DFS rates were 56% (95% CI 42, 69), 83% (95% CI 67, 91), and 73% (95% CI 53, 86) for Cohorts A, B, and C, respectively. The most common grade 3/4 treatment-related adverse events were neutropenia (26%), leukopenia (13%), and neuropathy (7%).

CONCLUSION

Administration of adjuvant eribulin after neoadjuvant chemotherapy was feasible and well tolerated. The 24-month DFS rate did not reach the study target levels in any of the cohorts and was similar to DFS previously described in these cohorts following neoadjuvant chemotherapy alone.

Transcriptome Analysis Reveals Key Genes and Pathways Associated with Metastasis in Breast Cancer

BACKGROUND

Metastasis is the major cause of death in breast cancer patients. Although the strategies targeting metastasis have promoted survival, the underlying mechanisms still remain unclear. In this study, we used microarray data of primary breast tumor, tumor derived from bone and liver, and skin metastatic tissue, to identify the key genes and pathways that are involved in metastasis in breast cancer.

METHODS

We first calculated the differentially expressed genes (DEGs) between three metastatic tissues and primary tumor tissue, and then used it to perform Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Further, we analyzed the correlation of genes enriched in GO terms and KEGG pathways with survival of breast cancer patients. To identify the key genes and pathways associated with metastasis, we overlapped the DEGs and KEGG pathways. In our in vitro experiments, we knocked down the key gene, ERLIN2, and detected the PI3K expression in tumor cells to evaluate their effect on tumor metastasis.

RESULTS

We identified six genes (ALOX15, COL4A6, LMB13, MTAP, PLA2G4A, TAT) that correlated with survival. Seven key genes (SNRPN, ARNT2, HDGFRP3, ERO1LB, ERLIN2, YBX2, EBF4) and seven signaling pathways (metabolic pathways, phagosome pathway, PI3K-AKT signaling pathway, focal adhesion, ECM-receptor interaction, pancreatic secretion, human papillomavirus infection) associated with metastasis were also identified. Our in vitro experiments revealed that ERLIN2 was highly expressed in MDA-MB231 cells compared to MCF-7 cells. Moreover, knockdown of ERLIN2 increased apoptosis, while inhibiting the proliferation, invasion, and migration ability of breast cancer cells. The PI3K/AKT signaling pathway was also found to be highly expressed in MDA-MB231 cells.

CONCLUSION

Our results reveal the key genes and signaling pathways that contribute to metastasis, and highlight that strategic targeting of ENLIN2 and PI3K/AKT signaling pathways could inhibit metastasis of breast cancer.

Therapeutic significance of hormone receptor positivity in patients with HER-2 positive breast cancer

Breast cancer with high expression of human epidermal growth factor receptor (HER)-2 represents a biologically and clinically heterogeneous group of neoplastic disorders. Importantly, hormone receptor expression has an effect on biological properties and affects the selection of therapies. On the basis of molecular genetics, four principal subtypes, including luminal A, luminal B, HER2-enriched (HER-2-E), and basal-like can be distinguished. Breast tumors characterized by HER-2 positivity and simultaneous expression of hormone receptors, triple positive breast cancers (TPBC) are of increasing interest owing to the unique biological characteristics associated with complex interactions between HER-2 and hormone receptor signaling pathways. Interactions between hormone receptors and HER-2 explain the decreased efficacy of hormonal therapy in comparison with HER-2-negative patients. The expression of estrogen receptors in HER-2 positive tumors may also be associated with resistance to anti-HER-2 treatment. Multiple available therapeutic options, including hormonal therapy, anti-HER-2 agents and cytotoxic drugs explain favorable prognosis of TPBC. Escalation and de-escalation therapeutic strategies that could result in lower toxicities are being investigated as well as combinations of anti-HER-2 agents with hormonal therapy, immunotherapy, cyclin dependent kinase 4/6 and phosphatidyl inositol-3-kinase inhibitors. Distinction between subtypes of HER-2-positive breast cancer and treatment diversification may result in improved outcomes in TPBC. A response to neoadjuvant therapy may serve in the tailoring of therapy management.

NAB-Paclitaxel Improves Disease-Free Survival in Early Breast Cancer: GBG 69–GeparSepto

PURPOSE

The GeparSepto trial demonstrated that weekly nanoparticle albumin-bound (NAB)–paclitaxel significantly improves the pathologic complete remission rate compared with weekly solvent-based (sb) paclitaxel followed by epirubicin plus cyclophosphamide as neoadjuvant treatment in patients with primary breast cancer (BC). Here, we report data on long-term outcomes.

METHODS

Patients with histologically confirmed primary BC were randomly assigned in a 1:1 ratio to 12 times weekly NAB-paclitaxel 150 mg/m2 (after study amendment, 125 mg/m2) or weekly sb-paclitaxel 80 mg/m2 followed in both arms by four times epirubicin 90 mg/m2 plus cyclophosphamide 600 mg/m2 every 3 weeks. Patients with human epidermal growth factor receptor 2 (HER2)-positive BC received dual antibody treatment with trastuzumab (8 mg/kg loading dose followed by 6 mg/kg every 3 weeks) and pertuzumab (840 mg loading dose followed by 420 mg every 3 weeks) concurrently to chemotherapy and continued for 1 year.

RESULTS

A total of 1,206 patients started treatment, 606 with NAB-paclitaxel and 600 with sb-paclitaxel. After a median follow-up of 49.6 months (range, 0.5 to 64.0 months), 243 invasive disease–free survival (iDFS) events were reported (143 in the sb-paclitaxel and 100 in the NAB-paclitaxel arm). At 4 years, overall patients treated with NAB-paclitaxel had a significantly better iDFS compared with sb-paclitaxel (84.0% v 76.3%; hazard ratio, 0.66; 95% CI, 0.51 to 0.86; P = .002), whereas overall survival did not significantly differ between the two treatment arms (89.7% v 87.2%, respectively; hazard ratio, 0.82; 95% CI, 0.59 to 1.16; P = .260). Long-term follow-up of the treatment-related peripheral sensory neuropathy (PSN) showed a significant decrease of the median time to resolve PSN after NAB-paclitaxel 125 mg/m2 compared with NAB-paclitaxel 150 mg/m2.

CONCLUSION

The significantly higher pathologic complete response rate with NAB-paclitaxel translated into a significantly improved iDFS in patients with early BC as compared with sb-paclitaxel. PSN improved much faster under NAB-paclitaxel 125 mg/m2 compared with NAB-paclitaxel 150 mg/m2.

Clinical Relevance of Collagen Protein Degradation Markers C3M and C4M in the Serum of Breast Cancer Patients Treated with Neoadjuvant Therapy in the GeparQuinto Trial

Background: Remodeling of extracellular matrix through collagen degradation is a crucial step in the metastatic cascade. The aim of this study was to evaluate the potential clinical relevance of the serum collagen degradation markers (CDM) C3M and C4M during neoadjuvant chemotherapy for breast cancer. Methods: Patients from the GeparQuinto phase 3 trial with untreated HER2-positive operable or locally advanced breast cancer were enrolled between 7 November 2007, and 9 July 2010, and randomly assigned to receive neoadjuvant treatment with EC/docetaxel with either trastuzumab or lapatinib. Blood samples were collected at baseline, after four cycles of chemotherapy and at surgery. Cutoff values were determined using validated cutoff finder software (C3M: Low ≤9.00 ng/mL, high >9.00 ng/mL, C4M: Low ≤40.91 ng/mL, high >40.91 ng/mL). Results: 157 patients were included in this analysis. At baseline, 11.7% and 14.8% of patients had high C3M and C4M serum levels, respectively. No correlation was observed between CDM and classical clinical-pathological factors. Patients with high levels of CDM were significantly more likely to achieve a pathological complete response (pCR, defined as ypT0 ypN0) than patients with low levels (C3M: 66.7% vs. 25.7%, p = 0.002; C4M: 52.7% vs. 26.6%, p = 0.031). Median levels of both markers were lower at the time of surgery than at baseline. In the multivariate analysis including clinical-pathological factors and C3M levels at baseline and changes in C3M levels between baseline and after four cycles of therapy, only C3M levels at baseline (p = 0.035, OR 4.469, 95%-CI 1.115–17.919) independently predicted pCR. In a similar model including clinical-pathological factors and C4M, only C4M levels at baseline (p = 0.028, OR 6.203, 95%-CI 1.220–31.546) and tumor size (p = 0.035, OR 4.900, 95%-CI 1.122–21.393) were independent predictors of pCR. High C3M levels at baseline did not correlate with survival in the entire cohort but were associated with worse disease-free survival (DFS; p = 0.029, 5-year DFS 40.0% vs. 74.9%) and overall survival (OS; p = 0.020, 5-year OS 60.0% vs. 88.3%) in the subgroup of patients randomized to lapatinib. In the trastuzumab arm, C3M did not correlate with survival. In the entire patient cohort, high levels of C4M at baseline were significantly associated with shorter DFS (p = 0.001, 5-year DFS 53.1% vs. 81.6%) but not with OS. When treatment arms were considered separately, the association with DFS was still significant (p = 0.014, 5-year DFS 44.4% vs. 77.0% in the lapatinib arm; p = 0.023, 5-year DFS 62.5% vs. 86.2% in the trastuzumab arm). Conclusions: Collagen degradation markers are associated with response to neoadjuvant therapy and seem to play a role in breast cancer.

The C Allele of ATM rs11212617 Associates With Higher Pathological Complete Remission Rate in Breast Cancer Patients Treated With Neoadjuvant Metformin

Background: The minor allele (C) of the single-nucleotide polymorphism (SNP) rs11212617, located near the ataxia telangiectasia mutated (ATM) gene, has been associated with an increased likelihood of treatment success with metformin in type 2 diabetes. We herein investigated whether the same SNP would predict clinical response to neoadjuvant metformin in women with early breast cancer (BC). Methods: DNA was collected from 79 patients included in the intention-to-treat population of the METTEN study, a phase 2 clinical trial of HER2-positive BC patients randomized to receive either metformin combined with anthracycline/taxane-based chemotherapy and trastuzumab or equivalent regimen without metformin, before surgery. SNP rs11212617 genotyping was assessed using allelic discrimination by quantitative polymerase chain reaction. Results: Logistic regression analyses revealed a significant relationship between the rs11212617 genotype and the ability of treatment arms to achieve a pathological complete response (pCR) in patients (odds ratio [OR]_{genotype×arm} = 10.33, 95% confidence interval [CI]: 1.29-82.89, p = 0.028). In the metformin-containing arm, patients bearing the rs11212617 C allele had a significantly higher probability of pCR (OR _A/C,C/C = 7.94, 95%CI: 1.60-39.42, p = 0.011). Conversely, no association was found between rs11212617 and clinical response in the reference arm (OR _A/C,C/C = 0.77, 95%CI: 0.20-2.92, p = 0.700). After controlling for tumor size and hormone receptor status, the rs11212617 C allele remained a significant predictor of pCR solely in the metformin-containing arm. Conclusions: If reproducible, the rs11212617 C allele might warrant consideration as a predictive clinical biomarker to inform the personalized use of metformin in BC patients. Trial Registration: EU Clinical Trials Register, EudraCT number 2011-000490-30. Registered 28 February 2011, https://www.clinicaltrialsregister.eu/ctr-search/trial/2011-000490-30/ES.

Potential Regulatory Roles of MicroRNAs and Long Noncoding RNAs in Anticancer Therapies

MicroRNAs and long noncoding RNAs have long been investigated due to their roles as diagnostic and prognostic biomarkers of cancers and regulators of tumorigenesis, and the potential regulatory roles of these molecules in anticancer therapies are attracting increasing interest as more in-depth studies are performed. The major clinical therapies for cancer include chemotherapy, immunotherapy, and targeted molecular therapy. MicroRNAs and long noncoding RNAs function through various mechanisms in these approaches, and the mechanisms involve direct targeting of immune checkpoints, cooperation with exosomes in the tumor microenvironment, and alteration of drug resistance through regulation of different signaling pathways. Herein we review the regulatory functions and significance of microRNAs and long noncoding RNAs in three anticancer therapies, especially in targeted molecular therapy, and their mechanisms.

Neoadjuvant Model as a Platform for Research in Breast Cancer and Novel Targets under Development in this Field

For decades, the neoadjuvant setting has provided a useful scenario for research in breast cancer. Historically, neoadjuvant clinical trials, either hormone therapy-based or chemotherapy-based, have tried to recapitulate the results of their counterpart adjuvant studies, but with smaller patient numbers, more rapid outcomes (clinical response and/or pathologic complete response (pCR)), together with additional biologic information. As for neoadjuvant chemotherapy trials, the increase in pCR rates has been recently accepted as an appropriate surrogate marker to accelerate drug approval in high-risk breast cancer patients. In this setting, with the exception of luminal A tumors, pCR has been associated with improved long-term outcomes, particularly when the analysis is based on specific trials for each breast cancer subtype. For luminal tumors receiving neoadjuvant endocrine therapy, Ki67 at 2-4 weeks and the preoperative endocrine prognostic index score are the most accepted intermediate markers of efficacy, which will be validated in ongoing larger trials. In this review, we describe the different neoadjuvant designs: from the classical randomized trials in which treatment is delivered for 6 or more months to short non-therapeutic presurgical studies lasting just 2 or 3 weeks. We also review the main neoadjuvant trials, either ongoing or completed, for luminal, triple-negative, and HER2-positive breast cancer. The translational effort and research of biomarkers conducted in these studies will be particularly addressed.

Extended Adjuvant Therapy with Neratinib Plus Fulvestrant Blocks ER/HER2 Crosstalk and Maintains Complete Responses of ER+/HER2+ Breast Cancers: Implications to the ExteNET Trial

PURPOSE

The phase III ExteNET trial showed improved invasive disease-free survival in patients with HER2⁺ breast cancer treated with neratinib versus placebo after trastuzumab-based adjuvant therapy. The benefit from neratinib appeared to be greater in patients with ER⁺/HER2⁺ tumors. We thus sought to discover mechanisms that may explain the benefit from extended adjuvant therapy with neratinib.Experimental Design: Mice with established ER⁺/HER2⁺ MDA-MB-361 tumors were treated with paclitaxel plus trastuzumab ± pertuzumab for 4 weeks, and then randomized to fulvestrant ± neratinib treatment. The benefit from neratinib was evaluated by performing gene expression analysis for 196 ER targets, ER transcriptional reporter assays, and cell-cycle analyses.

RESULTS

Mice receiving "extended adjuvant" therapy with fulvestrant/neratinib maintained a complete response, whereas those treated with fulvestrant relapsed rapidly. In three ER⁺/HER2⁺ cell lines (MDA-MB-361, BT-474, UACC-893) but not in ER⁺/HER2^- MCF7 cells, treatment with neratinib induced ER reporter transcriptional activity, whereas treatment with fulvestrant resulted in increased HER2 and EGFR phosphorylation, suggesting compensatory reciprocal crosstalk between the ER and ERBB RTK pathways. ER transcriptional reporter assays, gene expression, and immunoblot analyses showed that treatment with neratinib/fulvestrant, but not fulvestrant, potently inhibited growth and downregulated ER reporter activity, P-AKT, P-ERK, and cyclin D1 levels. Finally, similar to neratinib, genetic and pharmacologic inactivation of cyclin D1 enhanced fulvestrant action against ER⁺/HER2⁺ breast cancer cells.

CONCLUSIONS

These data suggest that ER blockade leads to reactivation of ERBB RTKs and thus extended ERBB blockade is necessary to achieve durable clinical outcomes in patients with ER⁺/HER2⁺ breast cancer.

Breast cancer development and progression: Risk factors, cancer stem cells, signaling pathways, genomics, and molecular pathogenesis

As the most commonly occurring cancer in women worldwide, breast cancer poses a formidable public health challenge on a global scale. Breast cancer consists of a group of biologically and molecularly heterogeneous diseases originated from the breast. While the risk factors associated with this cancer varies with respect to other cancers, genetic predisposition, most notably mutations in BRCA1 or BRCA2 gene, is an important causative factor for this malignancy. Breast cancers can begin in different areas of the breast, such as the ducts, the lobules, or the tissue in between. Within the large group of diverse breast carcinomas, there are various denoted types of breast cancer based on their invasiveness relative to the primary tumor sites. It is important to distinguish between the various subtypes because they have different prognoses and treatment implications. As there are remarkable parallels between normal development and breast cancer progression at the molecular level, it has been postulated that breast cancer may be derived from mammary cancer stem cells. Normal breast development and mammary stem cells are regulated by several signaling pathways, such as estrogen receptors (ERs), HER2, and Wnt/β-catenin signaling pathways, which control stem cell proliferation, cell death, cell differentiation, and cell motility. Furthermore, emerging evidence indicates that epigenetic regulations and noncoding RNAs may play important roles in breast cancer development and may contribute to the heterogeneity and metastatic aspects of breast cancer, especially for triple-negative breast cancer. This review provides a comprehensive survey of the molecular, cellular and genetic aspects of breast cancer.