Neoadjuvant endocrine therapy in breast cancer: current role and future perspectives

The crosstalk between ubiquitination and endocrine therapy

Endocrine therapy (ET), also known as hormone therapy, refers to the treatment of tumors by regulating and changing the endocrine environment and hormone levels. Its related mechanism is mainly through reducing hormone levels and blocking the binding of hormones to corresponding receptors, thus blocking the signal transduction pathway to stimulate tumor growth. However, with the application of ET, some patients show resistance to ET, which is attributed to abnormal accumulation of hormone receptors (HRs) and the production of multiple mutants of HRs. The targeted degradation of abnormal accumulation protein mediated by ubiquitination is an important approach that regulates the protein level and function of intracellular proteins in eukaryotes. Here, we provide a brief description of the traditional and novel drugs available for ET in this review. Then, we introduce the link between ubiquitination and ET. In the end, we elaborate the clinical application of ET combined with ubiquitination-related molecules. KEY MESSAGES: • A brief description of the traditional and novel drugs available for endocrine therapy (ET). • The link between ubiquitination and ET. • The clinical application of ET combined with ubiquitination-related molecules.

Neoadjuvant endocrine therapy in postmenopausal women with HR+/HER2- breast cancer

INTRODUCTION

While endocrine therapy is the standard-of-care adjuvant treatment for hormone receptor-positive (HR+) breast cancers, there is also extensive evidence for the role of pre-operative (or neoadjuvant) endocrine therapy (NET) in HR+ postmenopausal women.

AREAS COVERED

We conducted a thorough review of the published literature, to summarize the evidence to date, including studies of how NET compares to neoadjuvant chemotherapy, which NET agents are preferable, and the optimal duration of NET. We describe the importance of on-treatment assessment of response, the different predictors available (including Ki67, PEPI score, and molecular signatures) and the research opportunities the pre-operative setting offers. We also summarize recent combination trials and discuss how the COVID-19 pandemic led to increases in NET use for safe management of cases with deferred surgery and adjuvant treatments.

EXPERT OPINION

NET represents a safe and effective tool for the management of postmenopausal women with HR+/HER2- breast cancer, enabling disease downstaging and a wider range of surgical options. Aromatase inhibitors are the preferred NET, with evidence suggesting that longer regimens might yield optimal results. However, NET remains currently underutilised in many territories and institutions. Further validation of predictors for treatment response and benefit is needed to help standardise and fully exploit the potential of NET in the clinic.

The Present and Future of Neoadjuvant Endocrine Therapy for Breast Cancer Treatment

Simple Summary

The treatment of breast cancer has evolved considerably over the last two decades, leading toward individualized disease management. Hormone-sensitive breast cancers constitute the vast majority of cases and endocrine therapy is the mainstay of their treatment. On the other hand, neoadjuvant or pre-surgical treatments provide a number of advantages for tumor management. In this review we will discuss the existing evidence on neoadjuvant endocrine therapy, as well as its possible future indications.

Abstract

Endocrine therapy (ET) has established itself as an efficacious treatment for estrogen receptor-positive (ER+) breast cancers, with a reduction in recurrence rates and increased survival rates. The pre-surgical approach with chemotherapy (NCT) has become a common form of management for large, locally advanced, or high-risk tumors. However, a good response to NCT is not usually expected in ER+ tumors. Good results with primary ET, mainly in elderly women, have encouraged studies in other stages of life, and nowadays neoadjuvant endocrine treatment (NET) has become a useful approach to many ER+ breast cancers. The aim of this review is to provide an update on the current state of art regarding the present and the future role of NET.

Morphological and molecular changes following neoadjuvant endocrine therapy of oestrogen receptor-positive breast cancer: implications for clinical practice

AIMS

Neoadjuvant endocrine therapy (NAET) is used in the management of oestrogen receptor (ER)-positive breast cancer. The optimal method for histological assessment of response and the effect of NAET on the tumour morphology, grade and molecular profile remain unclear. The aim of this study is to investigate the NAET effect on tumour type, grade and molecular profile by analysing a well-characterised cohort of breast cancer samples in a single large UK tertiary referral centre, and to provide guidance on the pathological assessment of those lesions to inform adjuvant management and prognosis.

METHODS AND RESULTS

A single large-institution cohort of 132 patients who received NAET over a 13-year period was identified. Comprehensive clinical, histopathological and follow-up data were collected. A detailed histological review of a subset with residual post-treatment carcinoma was undertaken. Two carcinomas (both of the lobular type) achieved complete pathological response. Central scarring was seen in 49.3% of tumours post-treatment. Significant changes in tumour type (41.6%), tumour grade (downgrading in one-third of tumours), and progesterone receptor (PR) expression (22.3%), with a switch to PR-negative status in 17.6% of cases, were observed. The last of these was associated with an absence of tumour-infiltrating lymphocytes (P = 0.005). Ten per cent of cases showed a change in HER2 expression (P = 0.002). The median patient survival was 60 months, and downgrading of tumours was associated with better overall survival (P = 0.05).

CONCLUSIONS

We propose a histological method for assessment of residual carcinoma following NAET, and recommend repeat ER/PR/HER2 testing to inform management and prognosis.

Changes in Management Strategy and Impact of Neoadjuvant Therapy on Extent of Surgery in Invasive Lobular Carcinoma of the Breast: Analysis of the National Cancer Database (NCDB)

Background

Given reports of low response rates to neoadjuvant chemotherapy (NAC) in invasive lobular carcinoma (ILC), we evaluated whether use of alternative strategies such as neoadjuvant endocrine therapy (NET) is increasing. Additionally, we investigated whether NET is associated with more breast conservation surgery (BCS) and less extensive axillary surgery in those with ILC.

Patients and Methods

We queried the NCDB from 2010 to 2016 and identified all women with stage I–III hormone receptor positive, human epidermal growth factor receptor-2 negative (HR+/HER2−) ILC who underwent surgery. We used Cochrane–Armitage tests to evaluate trends in utilization of the following treatment strategies: NAC, short-course NET, long-course NET, and primary surgery. We compared rates of BCS and extent of axillary surgery stratified by clinical stage and tumor receptor subtype for each treatment strategy.

Results

Among 69,312 cases of HR+/HER2− ILC, NAC use decreased slightly (from 4.7 to 4.2%, p = 0.007), while there was a small but significant increase in long-course NET (from 1.6 to 2.7%, p < 0.001). Long-course NET was significantly associated with increased BCS in patients with cT2–cT4 disease and less extensive axillary surgery in clinically node positive patients with HR+/HER2− tumors.

Conclusions

Primary surgery remains the most common treatment strategy in patients with ILC. However, NAC use decreased slightly over the study period, while the use of long-course NET had a small increase and was associated with more BCS and less extensive axillary surgery.

Recent progress in immunotherapy of breast cancer targeting the human epidermal growth factor receptor 2 (HER2)

OBJECTIVE

Breast cancer is responsible for most of the cancer-induced deaths in women around the world. The current review will discuss different approaches of targeting HER2, an epidermal growth factor overexpressed in 30% of breast cancer cases.

DATA SOURCES

We conducted a search on Pubmed and Scopus databases to find studies relevant to HER2+ breast cancers and targeting HER2 as means of immunotherapy. Out of 1043 articles, 105 studies were included in this review.

DATA SUMMARY

As well as the introduction of HER2 and breast cancer subtypes, we discussed various aspects of HER2-targeting immunotherapy including monoclonal antibodies, Antibody-drug conjugates (ADCs), Chimeric Antigen Receptor (CAR) T-cells and vaccines.

CONCLUSIONS

Despite several ways of controlling breast cancer, the need to investigate new drugs and approaches seems to be much significant as this cancer still has a heavy burden on people's health and survival.

Correlation between MRI morphological response patterns and histopathological tumor regression after neoadjuvant endocrine therapy in locally advanced breast cancer: a randomized phase II trial

PURPOSE

To correlate MRI morphological response patterns with histopathological tumor regression grading system based on tumor cellularity in locally advanced breast cancer (LABC)-treated neoadjuvant with third-generation aromatase inhibitors.

METHODS

Fifty postmenopausal patients with ER-positive/HER-2-negative LABC treated with neoadjuvant letrozole and exemestane given sequentially in an intra-patient cross-over regimen for at least 4 months with MRI response monitoring at baseline as well as after at least 2 and 4 months on treatment. The MRI morphological response pattern was classified into 6 categories: 0/complete imaging response; I/concentric shrinkage; II/fragmentation; III/diffuse; IV/stable; and V/progressive. Histopathological tumor regression was assessed based on the recommendations from The Royal College of Pathologists regarding tumor cellularity.

RESULTS

Following 2 and 4 months with therapy, the most common MRI pattern was pattern II (24/50 and 21/50, respectively). After 4 months on therapy, the most common histopathological tumor regression grade was grade 3 (21/50). After 4 months an increasing correlation is observed between MRI patterns and histopathology. The overall correlation, between the largest tumor diameter obtained from MRI and histopathology, was moderate and positive (r = 0.50, P-value = 2e-04). Among them, the correlation was highest in type IV (r = 0.53).

CONCLUSION

The type II MRI pattern "fragmentation" was more frequent in the histopathological responder group; and types I and IV in the non-responder group. Type II pattern showed the best endocrine responsiveness and a relatively moderate correlation between sizes obtained from MRI and histology, whereas type IV pattern indicated endocrine resistance but the strongest correlation between MRI and histology.

Diagnostic and prognostic role of NR3C4 in breast cancer through a genomic network understanding

The androgen receptor (AR, NR3C4) is believed to participate in the development of breast cancer, but its molecular mechanism and role in prognosis is still controversial and opaque. This study aimed to explore the expression, associations with clinicopathologic features and underlying molecular mechanisms of AR in breast cancer. The present study investigated invasive breast carcinoma through comprehensive bioinformatics. The expression and mutation rate of AR in breast cancer was obtained from the TCGA database. Training survival prediction analysis was applied to the data extracted from the KM plotter database. The prediction of the survival cohort was validated using the bcGenExMiner database in breast cancer molecular subgroups. Represented immunohistochemical images of AR and its related expression with the molecular subtype status were generated. The underlying molecular mechanism for AR in breast cancer was analyzed with the GEO dataset and Gene Ontology. A protein-to-protein interaction network and core pathways were constructed to show the protein functions with AR. Our results show that AR expression was significantly higher in cancerous tissue than in normal breast tissue and differentially expressed in the clinical stages. AR would also generally be considered as a favorable prognostic biomarker when including the major molecular subtypes of breast cancer. AR IHC staining could be easily used in clinical applications. The major molecular functions for AR were regulating the cell cycle checkpoints and chromatin remodeling. Our investigation showed that AR expression level could be used as a favorable and independent prognostic prediction factor for the disease-free survival time in breast cancer, especially for the ER-positive subgroup. However, AR was not a sensitive prognostic biomarker for the prediction of overall survival time or for the PR and TBC subgroups. In terms of the underlying molecular mechanism, AR may mainly participate in the cell cycle checkpoints related to the G1/S transition of the mitotic cell cycle to control the subdivision of the epithelial terminal unit and chromatin remodeling in breast cancer.

Time to surgery among women treated with neoadjuvant systemic therapy and upfront surgery for breast cancer

PURPOSE

Time to surgery (TTS) is a potentially modifiable factor associated with survival after breast cancer diagnosis and can serve as a proxy for quality of oncologic care coordination. We sought to determine whether factors associated with delays in TTS vary between patients who receive neoadjuvant systemic therapy (NST) vs upfront surgery and whether the impact of these delays on overall survival (OS) varies with treatment sequence.

METHODS

Women ≥ 18 years old with Stage I-III breast cancer were identified in the National Cancer Database (2004-2014). Multivariate linear regression stratified by treatment sequence (upfront surgery vs NST [neoadjuvant chemotherapy {NAC}, neoadjuvant endocrine therapy {NAE}, or both {NACE}]) was used to identify factors associated with TTS. Cox proportional hazards models were used to estimate the effect of TTS on overall survival (OS).

RESULTS

Of 693,469 patients, 14.8% (n = 102,326) received NST (NAC n = 85,143, NAE n = 10,004, NACE n = 7179). Non-White race/ethnicity, no or government-issued insurance, more extensive surgery (i.e., mastectomy and contralateral prophylactic mastectomy vs breast-conserving surgery), and post-mastectomy reconstruction were associated with significantly longer adjusted TTS for NAC and upfront-surgery recipients, but only upfront-surgery patients had progressively worse OS with increasing TTS (> 180 vs ≤ 30 days: HR = 1.31, all p < 0.001).

CONCLUSIONS

Surgery extent, race/ethnicity, and insurance were associated with TTS across treatment groups, but longer TTS was only associated with worse OS in upfront-surgery patients. Our findings can help inform surgeon-patient communication, shared decision making, care coordination, and patients' expectations throughout both NST and in the perioperative period.

Machine Learning-Based Radiomics Nomogram Using Magnetic Resonance Images for Prediction of Neoadjuvant Chemotherapy Efficacy in Breast Cancer Patients

Purpose: The construction and validation of a radiomics nomogram based on machine learning using magnetic resonance image (MRI) for predicting the efficacy of neoadjuvant chemotherapy (NACT) in patients with breast cancer (BCa).

Methods: This retrospective investigation consisted of 158 patients who were diagnosed with BCa and underwent MRI before NACT, of which 33 patients experienced pathological complete response (pCR) by the postoperative pathological examination. The patients with BCa were divided into the training set (n = 110) and test set (n = 48) randomly. The features were selected by the maximum relevance minimum redundancy (mRMR) and absolute shrinkage and selection operator (LASSO) algorithm in the training set. In return, the radiomics signature was established using machine learning. The predictive score of each patient was calculated using the radiomics signature formula. Finally, the predictive scores and clinical factors were used to perform the multivariate logistic regression and construct the nomogram. Receiver operating characteristics (ROC) analyses were used to assess and validate the diagnostic accuracy of the nomogram in the test set. Lastly, the usefulness of the nomogram was confirmed via decision curve analysis (DCA).

Results: The radiomics signature was well-discriminated in the training set [AUC 0.835, specificity 71.32%, and sensitivity 82.61%], and test set (AUC 0.834, specificity 73.21%, and sensitivity 80%). Containing the radiomics signature and hormone status, the radiomics nomogram showed good calibration and discrimination in the training set [AUC 0.888, specificity 79.31%, and sensitivity 86.96%] and test set (AUC 0.879, specificity 82.19%, and sensitivity 83.57%). The decision curve indicated the clinical usefulness of our nomogram.

Conclusion: Our radiomics nomogram showed good discrimination in patients with BCa who experience pCR after NACT. The model may aid physicians in predicting how specific patients may respond to BCa treatments in the future.

Accuracy of breast MRI in patients receiving neoadjuvant endocrine therapy: comprehensive imaging analysis and correlation with clinical and pathological assessments

Purpose

To assess the accuracy of magnetic resonance imaging (MRI) measurements in locally advanced oestrogen receptor-positive and human epidermal growth factor receptor 2-negative breast tumours before, during and after neoadjuvant endocrine treatment (NET) for evaluation of tumour response in comparison with clinical and pathological assessments.

Methods

This prospective study enrolled postmenopausal patients treated neoadjuvant with letrozole and exemestane given sequentially in an intra-patient cross-over regimen. Fifty-four patients were initially recruited, but only 35 fulfilled the inclusion criteria and confirmed to participate with a median age of 77. Tumours were scanned with MRI prior to treatment, during the eighth week of treatment and prior to surgery. Additionally, changes in longest diameter on clinical examination (CE) and tumour size at pathology were determined. Pre- and post-operative measurements of tumour size were compared in order to evaluate tumour response.

Results

The correlation between post-treatment MRI size and pathology was moderate and higher with a correlation coefficient (r) 0.64 compared to the correlation between CE and pathology r = 0.25. Post-treatment MRI and clinical results had a negligible bias towards underestimation of lesion size. Tumour size on MRI and CE had 0.82 cm and 0.52 cm lower mean size than tumour size measured by pathology, respectively.

Conclusions

The higher correlation between measurements of residual disease obtained on MRI and those obtained with pathology validates the accuracy of imaging assessment during NET. MRI was found to be more accurate for estimating complete responses than clinical assessments and warrants further investigation in larger cohorts to validate this finding.

Electronic supplementary material

The online version of this article (10.1007/s10549-020-05852-7) contains supplementary material, which is available to authorized users.

A practical approach to the management of breast cancer in the COVID-19 era and beyond

The COVID-19 pandemic has resulted in a major shift in how breast services are being utilised and managed. The guidelines relating to this have been published by recognised medical associations from the UK, Europe and the USA, addressing many aspects of breast cancer care. There is an awareness that there may be limitations in resources during this time, and therefore, prioritisation strategies have been identified to ensure that breast cancer patients are appropriately treated, whilst reducing the risk of infection from COVID-19 to both patients and staff. Equally important is the consideration of how breast cancer services can be safely re-introduced, as infection rates from COVID-19 decline. However, until there is a definite management strategy for COVID-19, such as a vaccine being developed, it is likely that there will still be a significant impact from COVID-19 on breast cancer care. This paper, therefore, aims to highlight the current guidance and evidence regarding breast cancer management in the era of COVID-19, and also aims to look at future management strategies in this period of uncertainty.

Current Landscape of Breast Cancer Imaging and Potential Quantitative Imaging Markers of Response in ER-Positive Breast Cancers Treated with Neoadjuvant Therapy

In recent years, neoadjuvant treatment trials have shown that breast cancer subtypes identified on the basis of genomic and/or molecular signatures exhibit different response rates and recurrence outcomes, with the implication that subtype-specific treatment approaches are needed. Estrogen receptor-positive (ER+) breast cancers present a unique set of challenges for determining optimal neoadjuvant treatment approaches. There is increased recognition that not all ER+ breast cancers benefit from chemotherapy, and that there may be a subset of ER+ breast cancers that can be treated effectively using endocrine therapies alone. With this uncertainty, there is a need to improve the assessment and to optimize the treatment of ER+ breast cancers. While pathology-based markers offer a snapshot of tumor response to neoadjuvant therapy, non-invasive imaging of the ER disease in response to treatment would provide broader insights into tumor heterogeneity, ER biology, and the timing of surrogate endpoint measurements. In this review, we provide an overview of the current landscape of breast imaging in neoadjuvant studies and highlight the technological advances in each imaging modality. We then further examine some potential imaging markers for neoadjuvant treatment response in ER+ breast cancers.

Simvastatin Evokes An Unpredicted Antagonism For Tamoxifen In MCF-7 Breast Cancer Cells

Purpose

Tamoxifen (TAM) is a non-steroidal antiestrogen drug, used in the prevention and treatment of all stages of hormone-responsive breast cancer. Simvastatin (SIM) is a lipid-lowering agent and has been shown to inhibit cancer cell growth. The study aimed to investigate the effect of the combination of TAM and SIM in the treatment of estrogen receptor positive (ER+) breast cancer cell line, MCF-7, and in mice-bearing Ehrlich solid tumors.

Methods

MCF-7 cells were treated with different concentrations of TAM or/and SIM for 72 hours and the effects of the combination treatment on cytotoxicity, oxidative stress markers, apoptosis, angiogenesis, and metastasis were investigated using different techniques. In addition, tumor volume, oxidative markers, and inflammatory markers of the combined therapy were explored in mice bearing solid EAC tumors.

Results

The results showed that treatment of MCF-7 cells with the combination of 10 µM TAM, and 2 µM SIM significantly inhibited the increase in oxidative stress markers, LDH, and NF-kB induced by TAM. In addition, there was a significant decrease in the total apoptotic ratio, caspase-3 activity, and glucose uptake, while there was a non-significant change in Bax/bcl-2 ratio compared to the TAM-treated group. Using the isobologram equation, the drug interaction was antagonistic with combination index, CI=1.18. On the other hand, the combination regimen decreased VEGF, and matrix metalloproteinases, MMP 2&9 compared to TAM-treated cells. Additionally, in vivo, the combination regimen resulted in a non-significant decrease in the tumor volume, decreased oxidative markers, and the protein expression of TNF-α, and NF-κB compared to the TAM treated group.

Conclusion

Although the combination regimen of TAM and SIM showed an antagonistic drug interaction in MCF-7 breast cancer, it displayed favorable antiangiogenic, anti-metastatic, and anti-inflammatory effects.

Neoadjuvant Endocrine Therapy Versus Neoadjuvant Chemotherapy in Node-Positive Invasive Lobular Carcinoma

BACKGROUND

Neoadjuvant chemotherapy (NACT) is often recommended for patients with node-positive invasive lobular carcinoma (ILC) despite unclear benefit in this largely hormone receptor-positive (HR+) group. We sought to compare overall survival (OS) between patients with node-positive ILC who received neoadjuvant endocrine therapy (NET) and those who received NACT.

METHODS

Women with cT1-4c, cN1-3 HR+ ILC in the National Cancer Data Base (2004-2014) who underwent surgery following neoadjuvant therapy were identified. Kaplan-Meier curves and Cox proportional hazards modeling were used to estimate unadjusted and adjusted overall survival (OS), respectively.

RESULTS

Of the 5942 patients in the cohort, 855 received NET and 5087 received NACT. NET recipients were older (70 vs. 54 years) and had more comorbidities (Charlson-Deyo score ≥ 1: 21.1% vs. 11.5%), lower cT classification (cT3-4: 44.2% vs. 51.0%), lower rates of mastectomy (72.5% vs. 82.2%), lower rates of pathologic complete response (0% vs. 2.5%), and lower rates of postlumpectomy (73.2% vs. 91.0%) and postmastectomy (60.0% vs. 80.8%) radiation versus NACT recipients (all p < 0.001). NACT recipients had higher unadjusted 10-year OS versus NET recipients (57.9% vs. 36.0%), but after adjustment, there was no significant difference in OS between the two groups (p = 0.10).

CONCLUSIONS

Patients with node-positive ILC who received NET presented with smaller tumors, older age, and greater burden of comorbidities versus NACT recipients but had similar adjusted OS. While there is evidence from clinical trials supporting efficacy of NET in HR+ breast cancer, our findings suggest the need for further, histology-specific investigation regarding the optimal inclusion and sequence of endocrine therapy and chemotherapy in ILC.

A Phase II Randomized Study of Neoadjuvant Letrozole Plus Alpelisib for Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer (NEO-ORB)

PURPOSE

Addition of alpelisib to fulvestrant significantly extended progression-free survival in PIK3CA-mutant, hormone receptor-positive (HR+) advanced/metastatic breast cancer in the phase III SOLAR-1 study. The combination of alpelisib and letrozole also had promising activity in phase I studies of HR+ advanced/metastatic breast cancer. NEO-ORB aimed to determine whether addition of alpelisib to letrozole could increase response rates in the neoadjuvant setting.Patients and Methods: Postmenopausal women with HR+, human epidermal growth factor receptor 2-negative, T1c-T3 breast cancer were assigned to the PIK3CA-wild-type or PIK3CA-mutant cohort according to their tumor PIK3CA status, and randomized (1:1) to 2.5 mg/day letrozole with 300 mg/day alpelisib or placebo for 24 weeks. Primary endpoints were objective response rate (ORR) and pathologic complete response (pCR) rate for both PIK3CA cohorts.

RESULTS

In total, 257 patients were assigned to letrozole plus alpelisib (131 patients) or placebo (126 patients). Grade ≥3 adverse events (≥5% of patients) in the alpelisib arm were hyperglycemia (27%), rash (12%), and maculo-papular rash (8%). The primary objective was not met; ORR in the alpelisib versus placebo arm was 43% versus 45% and 63% versus 61% in the PIK3CA-mutant and wild-type cohorts, respectively. pCR rates were low in all groups. Decreases in Ki-67 were similar across treatment arms and cohorts. In PIK3CA-mutant tumors, alpelisib plus letrozole treatment induced a greater decrease in phosphorylated AKT versus placebo plus letrozole.

CONCLUSIONS

In contrast to initial results in advanced/metastatic disease, addition of alpelisib to 24-week neoadjuvant letrozole treatment did not improve response in patients with HR+ early breast cancer.

Current Status of Neoadjuvant Endocrine Therapy in Early Stage Breast Cancer

OPINION STATEMENT

Neoadjuvant endocrine therapy (NET) with Ki67-based response monitoring is a practical, cost-effective approach to the management of clinical stage II and III estrogen receptor-positive (ER+) breast cancer. In addition to marked improvements in rates of breast conservation, the identification of extreme responders on the basis of the preoperative endocrine prognostic index (PEPI) provides a rationale to avoid chemotherapy on the basis of highly favorable prognosis in some patients. Finally, samples accrued from patients treated with neoadjuvant therapy are providing valuable insights into the molecular basis for intrinsic resistance to endocrine therapy and promise a more rational basis and precise approach to the systemic treatment of ER+ breast cancer.

Luminal lncRNAs Regulation by ERα-Controlled Enhancers in a Ligand-Independent Manner in Breast Cancer Cells

Estrogen receptor-α (ERα) is a ligand-inducible protein which mediates estrogenic hormones signaling and defines the luminal BC phenotype. Recently, we demonstrated that even in absence of ligands ERα (apoERα) binds chromatin sites where it regulates transcription of several protein-coding and lncRNA genes. Noteworthy, apoERα-regulated lncRNAs marginally overlap estrogen-induced transcripts, thus representing a new signature of luminal BC genes. By the analysis of H3K27ac enrichment in hormone-deprived MCF-7 cells, we defined a set of Super Enhancers (SEs) occupied by apoERα, including one mapped in proximity of the DSCAM-AS1 lncRNA gene. This represents a paradigm of apoERα activity since its expression is largely unaffected by estrogenic treatment, despite the fact that E2 increases ERα binding on DSCAM-AS1 promoter. We validated the enrichment of apoERα, p300, GATA3, FoxM1 and CTCF at both DSCAM-AS1 TSS and at its associated SE by ChIP-qPCR. Furthermore, by analyzing MCF-7 ChIA-PET data and by 3C assays, we confirmed long range chromatin interaction between the SE and the DSCAM-AS1 TSS. Interestingly, CTCF and p300 binding showed an enrichment in hormone-depleted medium and in the presence of ERα, elucidating the dynamics of the estrogen-independent regulation of DSCAM-AS1 expression. The analysis of this lncRNA provides a paradigm of transcriptional regulation of a luminal specific apoERα regulated lncRNA.

Recent Advances in the Neoadjuvant Treatment of Breast Cancer

In the last few decades, neoadjuvant therapy for breast cancer has gained considerable therapeutic importance. Despite extensive clinical investigations, it has not yet been clarified whether neoadjuvant therapy would result in improved survival in comparison with the standard adjuvant setting in any subgroups of patients with breast cancer. Chemotherapy is especially effective in the treatment of endocrine insensitive tumors, and such ther-apeutic benefit can be assumed for patients with triple-negative, or hormone receptor-negative and human epidermal growth factor receptor 2 (HER2)-positive breast cancer. However, dose escalation, modification of the therapeutic regimens according to early tumor response, as well as the optimal sequence of administration are still matters of debate. There is a current debate between clinical experts regarding the concomitant and sequential administration of carboplatin and capecitabine, respectively, as part of the standard neoadjuvant treatment, as well as the use of bevacizumab, as part of the preoperative treatment. In case of HER2 positive tumors, an anti-HER2 agent can be administered as part of the preoperative treatment, and according to preliminary clinical data, dual HER2 blockade can also be reasonable. Further, chemotherapy-free regimens can be justified in highly endocrine sensitive tumors, while immune modulating agents may also gain particular importance in the case of certain subtypes of breast cancer. Several small-molecule targeted therapies are under clinical investigation and are expected to provide new neoadjuvant treatment options. However, novel, more predictive biomarkers are required for further evaluation of the neoadjuvant therapies, as well as the effect of novel targeted agents intended to be incorporated into neoadjuvant therapy.

Is there a role for salvage radiotherapy in locally advanced breast cancer refractory to neoadjuvant chemotherapy?

INTRODUCTION

Locally advanced breast cancer (LABC) is a major problem, especially in developing countries. The standard treatment for LABC is neoadjuvant chemotherapy, with or without anti-Her2 therapy, followed by surgery, radiotherapy, and adjuvant systemic treatment if appropriate. However, there are few data in the literature addressing alternatives when neoadjuvant chemotherapy fails to reduce the tumour for surgery.

MATERIALS AND METHODS

We conducted a retrospective study including all patients who had non-metastatic LABC treated with neoadjuvant chemotherapy and who were not eligible for surgical resection; these patients were submitted to salvage radiotherapy (RTX) between January 2000 and December 2012 at the Brazilian National Cancer Institute.

RESULTS

Fifty-seven patients were included, with a median age of 51 (23-72) years. The most frequent clinical stages were IIIA and IIIB, corresponding to 19.3% and 70.2%, respectively; mean tumour size was 8.74 (3-18) cm, and 44 patients (77.2%) had nodal involvement. Chemotherapeutic regimens containing anthracyclines were prescribed to 98.2% of the patients. Fifteen patients (26.3%) received taxanes and anthracyclines. Radiation dose was 50 Gy divided into 25 fractions; 43 patients (75.4%) had their tumours downsized by RTX and underwent mastectomy. Overall survival (OS) was 38 (23-52) months. Patients who were submitted to surgery had an OS of 49 (28-70) months and those who were not eligible for mastectomy after radiotherapy had an OS of 18 (9-27) months.

CONCLUSION

This retrospective study confirms that RTX is an effective treatment to downsize LABC tumours with low or no response to chemotherapy, thereby enabling surgical resection which may improve overall patient outcome.

[Systemic neoadjuvant therapy of luminal breast cancer in 2016]

Neoadjuvant systemic therapies have been extensively evaluated in luminal breast cancer. Conventional cytotoxic chemotherapy increases breast conservation rate, albeit with a low level of complete pathological response of uncertain clinical significance. Endocrine therapies allow similar clinical results with much less side effects. Biological criteria of response to endocrine therapies are still being defined. The neoadjuvant setting must be used for early development of new compounds and to further document biological mechanisms of sensitivity and resistance to treatments.