Clinical and genomic analysis of a randomised phase II study evaluating anastrozole and fulvestrant in postmenopausal patients treated for large operable or locally advanced hormone-receptor-positive breast cancer

Neoadjuvant Therapy: Current Landscape and Future Horizons for ER-Positive/HER2-Negative and Triple-Negative Early Breast Cancer

OPINION STATEMENT

Navigating the complex landscape of breast cancer treatment involves distinct strategies for luminal and triple-negative subtypes. While neoadjuvant chemotherapy historically dominates the approach for aggressive triple-negative tumors, recent evidence highlights the transformative impact of immunotherapy, alongside chemotherapy, in reshaping treatment paradigms. In luminal cancers, endocrine therapy, notably aromatase inhibitors, demonstrates promising outcomes in postmenopausal patients with low-grade luminal A tumors. However, integrating targeted therapies like CDK4/6 inhibitors in neoadjuvant setting remains inconclusive. Identifying predictive factors for treatment response, especially in luminal tumors, poses a challenge, emphasizing the necessity for ongoing research. A multidisciplinary approach, tailored to individual patient profiles, is crucial for maximizing efficacy while minimizing toxicity. As we strive to optimize breast cancer management, a comprehensive understanding of the distinct characteristics and treatment implications of luminal and triple-negative subtypes, including the transformative role of immunotherapy, is essential for informed decision-making and personalized care.

Neoadjuvant endocrine treatment in hormone receptor-positive breast cancer: Does it result in more breast-conserving surgery?

BACKGROUND

Patients with locally advanced endocrine positive tumors who will not benefit from chemotherapy can be treated by either primary surgery or neoadjuvant endocrine therapy (NET). How often does NET result in breast-conserving surgery (BCS)?

METHODS

We conducted a literature search in PubMed and Embase, to identify articles on surgical treatment after NET.

RESULTS

In 19 studies the pathological complete response (pCR) rate was reported after NET; an overall pCR rate of 1% was found. Compared with neoadjuvant chemotherapy (NCT), the BCS rate was significantly higher after NET (OR 0.60; 95% CI, 0.51-0.69; P < 0.00001). The surgical conversion rate was reported in eight studies [4-75.9%], with a mean of 30.2%.

CONCLUSION

This review found that one out of three patients becomes eligible for BCS after treatment with NET.

Chemotherapy combined with endocrine neoadjuvant therapy for hormone receptor-positive local advanced breast cancer: a case report and literature review

Background

Early studies have revealed antagonistic effects associated with stacking chemotherapy (CT) and endocrine therapy (ET), thereby conventional wisdom does not advocate the simultaneous combination of these two treatment modalities. Limited clinical studies exist on the combined use of neoadjuvant CT (NACT) and neoadjuvant ET (NET), and there are no reported instances of concurrent neoadjuvant treatment for locally advanced breast cancer (LABC) using capecitabine and fulvestrant (FUL).

Case presentation

We reported a 54-year-old woman who was diagnosed with hormone receptor-positive (HR+) LABC at our hospital. After neoadjuvant treatment involving two distinct CT regimens did not lead to tumor regression. Consequently, the patient was transitioned to concurrent capecitabine and FUL therapy. This change resulted in favorable pathological remission without any significant adverse events during treatment.

Conclusions

A novel approach involving concurrent neoadjuvant therapy with CT and endocrine therapy may offer a potentially effective treatment avenue for some cases with HR+ LABC.

Cytomorphological Disparities in Invasive Breast Cancer Cells following Neoadjuvant Endocrine Therapy and Chemotherapy

INTRODUCTION

Neoadjuvant endocrine therapy (NAE) offers a breast-conserving surgery rate and clinical response rate similar to those of neoadjuvant chemotherapy (NAC), while presenting fewer adverse events and lower pathological complete response rates. The assessment of pathological response determines degenerative changes and predicts the prognosis of breast cancer treated with NAC. This study clarified the degenerative changes occurring in breast cancer following NAE.

METHODS

Our study encompassed two groups: NAE, consisting of 15 patients, and NAC, comprising 18 patients. Tissue samples were obtained from core needle biopsies and surgeries. Nuclear and cell areas were calculated using Autocell analysis. Furthermore, we assessed markers associated with microtubule depolymerization (KIF2A) and initiators of apoptosis (caspase-9).

RESULTS

In the NAC group, we observed significant increases in both cytoplasmic and cell areas. These changes in cytoplasm and cells were notably more pronounced in the NAC group compared to the NAE group. After treatment, KIF2A exhibited a decrease, with the magnitude of change being greater in the NET group than in the NAC group. However, no discernible differences were found in caspase-9 expression between the two groups.

CONCLUSION

Our findings indicate that NAE induces condensation in cancer cells via cell cycle arrest or apoptosis. Conversely, NAC leads to cell enlargement due to the absence of microtubule depolymerization. These discrepancies underscore the importance of accounting for these distinctions when establishing criteria for evaluating pathological responses.

Neoadjuvant endocrine therapy in ER-positive breast cancer: evolution, indication, and tailored treatment strategy

In recent years, endocrine therapy (ET), an effective systemic treatment for the management of estrogen receptor (ER)-positive breast cancers, has regained interest as a neoadjuvant therapy based on evidence that ET can fulfill the aim of neoadjuvant systemic treatment for tumor shrinkage as well as elucidate important clinical information on endocrine sensitivity that enables the prognostication of patients. Moreover, neoadjuvant endocrine therapy (NET) potentially provides an opportunity for early assessment of the clinical efficacy of novel agents. Furthermore, recently reported trials have generated evidence for a more tailored approach for perioperative management of ER-positive breast cancer using clinical and molecular biomarkers, and this has provided a rationale that enables the broadening of clinical indications for NET. This review discusses the current evidence for NET, the evolution of NET trials, clinical indications, and NET-based treatment strategies.

Neoadjuvant endocrine therapy for luminal breast tumors: State of the art, challenges and future perspectives

Neoadjuvant endocrine treatment (NET) associates to satisfactory rates of breast conservative surgery and conversions from inoperable to operable hormone receptor-positive (HR+)/HER2-negative breast cancer (BC), with less toxicities than neoadjuvant chemotherapy (NACT) and similar outcomes. Hence, it has been proposed as a logical alternative to NACT in patients with HR+/HER2- BC candidate to a neoadjuvant approach. Nevertheless, potential barriers to the widespread use of NET include the heterogeneous nature of patient response coupled with the long duration needed to achieve a clinical response. However, interest in NET has significantly increased in the last decade, owing to more in-depth investigation of several biomarkers for a more adequate patient selection and on-treatment benefit monitoring, such as PEPI score, Ki67 and genomic assays. This review is intended to describe the state-of-the-art regarding NET, its future perspectives and potential integration with molecular biomarkers for the optimal selection of patients, regimen and duration of (neo)adjuvant treatments.

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.

Estrogen Receptor Alpha Gene Amplification Is an Independent Predictor of Long-Term Outcome in Postmenopausal Patients with Endocrine-Responsive Early Breast Cancer

PURPOSE

Estrogen receptor (ER) expression is a prognostic parameter in breast cancer, and a prerequisite for the use of endocrine therapy. In ER+ early breast cancer, however, no receptor-associated biomarker exists that identifies patients with a particularly favorable outcome. We have investigated the value of ESR1 amplification in predicting the long-term clinical outcome in tamoxifen-treated postmenopausal women with endocrine-responsive breast cancer.

EXPERIMENTAL DESIGN

394 patients who had been randomized into the tamoxifen-only arm of the prospective randomized ABCSG-06 trial of adjuvant endocrine therapy with available formalin-fixed, paraffin-embedded tumor tissue were included in this analysis. IHC ERα expression was evaluated both locally and in a central lab using the Allred score, while ESR1 gene amplification was evaluated by FISH analysis using the ESR1/CEP6 ratio indicating focal copy number alterations.

RESULTS

Focal ESR1 copy-number elevations (amplifications) were detected in 187 of 394 (47%) tumor specimens, and were associated with a favorable outcome: After a median follow-up of 10 years, women with intratumoral focal ESR1 amplification had a significantly longer distant recurrence-free survival [adjusted HR, 0.48; 95% confidence interval (CI), 0.26-0.91; P = 0.02] and breast cancer-specific survival (adjusted HR 0.47; 95% CI, 0.27-0.80; P = 0.01) as compared with women without ESR1 amplification. IHC ERα protein expression, evaluated by Allred score, correlated significantly with focal ESR1 amplification (P < 0.0001; χ2 test), but was not prognostic by itself.

CONCLUSIONS

Focal ESR1 amplification is an independent and powerful predictor for long-term distant recurrence-free and breast cancer-specific survival in postmenopausal women with endocrine-responsive early-stage breast cancer who received tamoxifen for 5 years.

Patterns of genomic change in residual disease after neoadjuvant chemotherapy for estrogen receptor-positive and HER2-negative breast cancer

BACKGROUND

Treatment of patients with residual disease after neoadjuvant chemotherapy for breast cancer is an unmet clinical need. We hypothesised that tumour subclones showing expansion in residual disease after chemotherapy would contain mutations conferring drug resistance.

METHODS

We studied oestrogen receptor and/or progesterone receptor-positive, HER2-negative tumours from 42 patients in the EORTC 10994/BIG 00-01 trial who failed to achieve a pathological complete response. Genes commonly mutated in breast cancer were sequenced in pre and post-treatment samples.

RESULTS

Oncogenic driver mutations were commonest in PIK3CA (38% of tumours), GATA3 (29%), CDH1 (17%), TP53 (17%) and CBFB (12%); and amplification was commonest for CCND1 (26% of tumours) and FGFR1 (26%). The variant allele fraction frequently changed after treatment, indicating that subclones had expanded and contracted, but there were changes in both directions for all of the commonly mutated genes.

CONCLUSIONS

We found no evidence that expansion of clones containing recurrent oncogenic driver mutations is responsible for resistance to neoadjuvant chemotherapy. The persistence of classic oncogenic mutations in pathways for which targeted therapies are now available highlights their importance as drug targets in patients who have failed chemotherapy but provides no support for a direct role of driver oncogenes in resistance to chemotherapy. CLINICALTRIALS.GOV: EORTC 10994/BIG 1-00 Trial registration number NCT00017095.

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.

Neoadjuvant Endocrine Therapy in Breast Cancer Management: State of the Art

Endocrine therapy is the mainstay of treatment in HR+/HER2- breast cancers, which represent about 70% of all breast cancers. Neoadjuvant therapy has been developed since the 1990s to address several issues, including breast-conserving surgery (BCS) and improvement of survival rates. For a long time, neoadjuvant endocrine therapy (NET) was confined to frail patients in order to improve surgery outcome. Since the 2000s, NET now plays a central role as a research tool for predictive endocrine sensitivity biomarkers and targeted therapies. One of the major issues in early HR+/HER2- breast cancer is to identify patients in whom chemotherapy can be safely withheld. In vivo assessment of response to NET might be the best treatment strategy to address this issue.

Predictive factors of 5-year relapse-free survival in HR+/HER2- breast cancer patients treated with neoadjuvant endocrine therapy: pooled analysis of two phase 2 trials

BACKGROUND

Few data are available on survival and predictive factors in early breast cancer (BC) patients treated with neoadjuvant endocrine therapy (NET).

METHODS

This is a pooled analysis of two multicentre, randomised non-comparative phase 2 clinical trials evaluating neoadjuvant anastrozole and fulvestrant efficacy for postmenopausal HR+/HER2- breast cancer patients: HORGEN (NCT00871858) and CARMINA02 (NCT00629616) studies.

RESULTS

In total, 236 patients were included in CARMINA02 and HORGEN trials. Modified intention-to-treat analysis was available for 217 patients. Median follow-up was 65.2 months. Relapse-free survival (RFS) and overall survival (OS) at 5 years were 83.7% (95% CI: 77.9-88) and 92.7% (95% CI: 88.2-95.6), respectively, with no difference between treatment arms. On univariate analysis, tumour staging (T2 vs T3-4; p = 0.0001), Ki-67 at surgery (≤10% vs >10%; p = 0.0093), pathological tumour size (pT1-2 vs pT3-4; p = 0.0012) and node status (pN negative vs positive; p = 0.007), adjuvant chemotherapy (p = 0.0167) and PEPI score (PEPI group I + II vs III; p = 0.0004) were associated with RFS. No events were observed in patients with pathological response according to the Sataloff classification. Multivariate analysis showed that preoperative endocrine prognostic index (PEPI) group III was associated with significantly worse RFS (p = 0.0069, hazard ratio = 3.33 (95% CI: 1.39-7.98)).

CONCLUSIONS

Postmenopausal HR+/HER2- breast cancer patients receiving NET generally have a favourable outcome. The PEPI score identifies a subset of patients of poorer prognosis who are candidates for further additional treatment.

Neoadjuvant endocrine therapy: A potential strategy for ER-positive breast cancer

A potential strategy for patients with estrogen receptor (ER)-positive breast cancer is necessary to replace neoadjuvant chemotherapy which has limited benefit. Neoadjuvant endocrine therapy (NAE) has been indicated to be a favorable alternate approach to downstage large or locally advanced breast cancer in ER-positive, human epidermal growth factor receptor 2 (HER2)-negative (ER+/HER2-) patients, especially postmenopausal women. Previous studies have demonstrated the efficacy of various endocrine agents in NAE. Aromatase inhibitors (AIs) have proven superiority over tamoxifen as a suitable choice to optimize treatment efficacy. Fulvestrant was recently reported as an effective agent, similar to AIs. Furthermore, the addition of targeted agents exerts synergistic antiproliferative effects with endocrine agents and rapidly improves response rates in both endocrine sensitive and resistant tumors. The neoadjuvant platform provides a unique opportunity to define the appropriate strategy and address the mechanisms of endocrine resistance. In addition, the predictive value of biomarkers and genomic assays in NAE is under investigation to evaluate individual effects and validate biomarker-based strategies. In this review, we discuss the most relevant evidence on the potential of NAE for ER+ breast cancer. The current understanding also offers new insights into the identification of the optimal settings and valuable predictive tools of NAE to guide clinical treatment decisions and achieve beneficial therapeutic effects.

ESR1 alterations and metastasis in estrogen receptor positive breast cancer

Endocrine therapy is essential for the treatment of patients with estrogen receptor positive (ER+) breast cancer, however, resistance and the development of metastatic disease is common. Understanding how ER+ breast cancer metastasizes is critical since the major cause of death in breast cancer is metastasis to distant organs. Results from many studies suggest dysregulation of the estrogen receptor alpha gene (ESR1 ) contributes to therapeutic resistance and metastatic biology. This review covers both pre-clinical and clinical evidence on the spectrum of ESR1 alterations including amplification, point mutations, and genomic rearrangement events driving treatment resistance and metastatic potential of ER+ breast cancer. Importantly, we describe how these ESR1 alterations may provide therapeutic opportunities to improve outcomes in patients with lethal, metastatic breast cancer.

Genomic Instability and TP53 Genomic Alterations Associate With Poor Antiproliferative Response and Intrinsic Resistance to Aromatase Inhibitor Treatment

PURPOSE

Although aromatase inhibitor (AI) treatment is effective in estrogen receptor-positive postmenopausal breast cancer, resistance is common and incompletely explained. Genomic instability, as measured by somatic copy number alterations (SCNAs), is important in breast cancer development and prognosis. SCNAs to specific genes may drive intrinsic resistance, or high genomic instability may drive tumor heterogeneity, which allows differential response across tumors and surviving cells to evolve resistance to treatment rapidly. We therefore evaluated the relationship between SCNAs and intrinsic resistance to treatment as measured by a poor antiproliferative response.

PATIENTS AND METHODS

SCNAs were determined by single nucleotide polymorphism array in baseline and surgery core-cuts from 73 postmenopausal patients randomly assigned to receive 2 weeks of preoperative AI or no AI in the Perioperative Endocrine Therapy-Individualizing Care (POETIC) trial. Fifty-six samples from the AI group included 28 poor responders (PrRs, less than 60% reduction in protein encoded by the MKI67 gene [Ki-67]) and 28 good responders (GdRs, greater than 75% reduction in Ki-67). Exome sequencing was available for 72 pairs of samples.

RESULTS

Genomic instability correlated with Ki-67 expression at both baseline (P < .001) and surgery (P < .001) and was higher in PrRs (P = .048). The SCNA with the largest difference between GdRs and PrRs was loss of heterozygosity observed at 17p (false discovery rate, 0.08), which includes TP53. Nine of 28 PrRs had loss of wild-type TP53 as a result of mutations and loss of heterozygosity compared with three of 28 GdRs. In PrRs, somatic alterations of TP53 were associated with higher genomic instability, higher baseline Ki-67, and greater resistance to AI treatment compared with wild-type TP53.

CONCLUSION

We observed that primary tumors with high genomic instability have an intrinsic resistance to AI treatment and do not require additional evolution to develop resistance to estrogen deprivation therapy.

Neoadjuvant Endocrine Therapy: Who Benefits Most?

Neoadjuvant endocrine therapy (NET) can be effective at downstaging patients with estrogen receptor-positive tumors and identifying those tumors that are endocrine sensitive and resistant. The optimal prognostic markers for stratification are under investigation. Use of NET will allow the identification of patients with estrogen receptor-positive tumors who might benefit from additional treatment and allow better understanding of endocrine resistance.

Role of steroid receptor and coregulator mutations in hormone-dependent cancers

Steroid hormones mediate critical lineage-specific developmental and physiologic responses. They function by binding their cognate receptors, which are transcription factors that drive specific gene expression programs. The requirement of most prostate cancers for androgen and most breast cancers for estrogen has led to the development of endocrine therapies that block the action of these hormones in these tumors. While initial endocrine interventions are successful, resistance to therapy often arises. We will review how steroid receptor-dependent genomic signaling is affected by genetic alterations in endocrine therapy resistance. The detailed understanding of these interactions will not only provide improved treatment options to overcome resistance, but, in the future, will also be the basis for implementing precision cancer medicine approaches.

Neoadjuvant Endocrine Therapy for Estrogen Receptor-Positive Breast Cancer: A Systematic Review and Meta-analysis

Importance

Estrogen receptor-positive (ER+) tumors of the breast are generally highly responsive to endocrine treatment. Although endocrine therapy is the mainstay of adjuvant treatment for ER+ breast cancer, the role of endocrine therapy in the neoadjuvant setting is unclear.

Objective

To evaluate the effect of neoadjuvant endocrine therapy (NET) on the response rate and the rate of breast conservation surgery (BCS) for ER+ breast cancer.

Data Sources

Based on PRISMA guidelines, a librarian-led search of PubMed and Ovid MEDLINE was performed to identify eligible trials published from inception to May 15, 2015. The search was performed in May 2015.

Study Selection

Inclusion criteria were prospective, randomized, neoadjuvant clinical trials that reported response rates with at least 1 arm incorporating NET (n = 20). Two authors independently analyzed the studies for inclusion.

Data Extraction and Synthesis

Pooled odds ratios (ORs), 95% CIs, and P values were estimated for end points using the fixed- and random-effects statistical model.

Results

The analysis included 20 studies with 3490 unique patients. Compared with combination chemotherapy, NET as monotherapy with aromatase inhibitors had a similar clinical response rate (OR, 1.08; 95% CI, 0.50-2.35; P = .85; n = 378), radiological response rate (OR, 1.38; 95% CI, 0.92-2.07; P = .12; n = 378), and BCS rate (OR, 0.65; 95% CI, 0.41-1.03; P = .07; n = 334) but with lower toxicity. Aromatase inhibitors were associated with a significantly higher clinical response rate (OR, 1.69; 95% CI, 1.36-2.10; P < .001; n = 1352), radiological response rate (OR, 1.49; 95% CI, 1.18-1.89; P < .001; n = 1418), and BCS rate (OR, 1.62; 95% CI, 1.24-2.12; P < .001; n = 918) compared with tamoxifen. Dual combination therapy with growth factor pathway inhibitors was associated with a higher radiological response rate (OR, 1.59; 95% CI, 1.04-2.43; P = .03; n = 355), but not clinical response rate (OR, 0.76; 95% CI, 0.54-1.07; P = .11; n = 537), compared with endocrine monotherapy. The incidence of pathologic complete response was low (<10%).

Conclusions and Relevance

Neoadjuvant endocrine therapy, even as monotherapy, is associated with similar response rates as neoadjuvant combination chemotherapy but with significantly lower toxicity, suggesting that NET needs to be reconsidered as a potential option in the appropriate setting. Additional research is needed to develop rational NET combinations and predictive biomarkers to personalize the optimal neoadjuvant strategy for ER+ breast cancer.

Impact of mutational profiles on response of primary oestrogen receptor-positive breast cancers to oestrogen deprivation

Pre-surgical studies allow study of the relationship between mutations and response of oestrogen receptor-positive (ER+) breast cancer to aromatase inhibitors (AIs) but have been limited to small biopsies. Here in phase I of this study, we perform exome sequencing on baseline, surgical core-cuts and blood from 60 patients (40 AI treated, 20 controls). In poor responders (based on Ki67 change), we find significantly more somatic mutations than good responders. Subclones exclusive to baseline or surgical cores occur in ∼30% of tumours. In phase II, we combine targeted sequencing on another 28 treated patients with phase I. We find six genes frequently mutated: PIK3CA, TP53, CDH1, MLL3, ABCA13 and FLG with 71% concordance between paired cores. TP53 mutations are associated with poor response. We conclude that multiple biopsies are essential for confident mutational profiling of ER+ breast cancer and TP53 mutations are associated with resistance to oestrogen deprivation therapy.

[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.

Strategies in functional proteomics: Unveiling the pathways to precision oncology

Personalised strategies in cancer care are required to overcome the therapeutic challenges posed by variability between patients and disease subsets. To this end, enhanced precision tools must be developed to describe the molecular drivers of malignant proliferation. Such tools must also identify druggable targets and biomarkers in order to provide essential information regarding drug development and therapeutic outcome. Here we discuss how proteomics-based approaches provide a set of viable methodologies capable of delivering quantitative information throughout the main stages of personalised oncology and a ratiometric platform that delivers systems-wide methods for drug evaluation.

FOXA1 overexpression mediates endocrine resistance by altering the ER transcriptome and IL-8 expression in ER-positive breast cancer

Forkhead box protein A1 (FOXA1) is a pioneer factor of estrogen receptor α (ER)-chromatin binding and function, yet its aberration in endocrine-resistant (Endo-R) breast cancer is unknown. Here, we report preclinical evidence for a role of FOXA1 in Endo-R breast cancer as well as evidence for its clinical significance. FOXA1 is gene-amplified and/or overexpressed in Endo-R derivatives of several breast cancer cell line models. Induced FOXA1 triggers oncogenic gene signatures and proteomic profiles highly associated with endocrine resistance. Integrated omics data reveal IL8 as one of the most perturbed genes regulated by FOXA1 and ER transcriptional reprogramming in Endo-R cells. IL-8 knockdown inhibits tamoxifen-resistant cell growth and invasion and partially attenuates the effect of overexpressed FOXA1. Our study highlights a role of FOXA1 via IL-8 signaling as a potential therapeutic target in FOXA1-overexpressing ER-positive tumors.

Randomized phase 2 neoadjuvant trial evaluating anastrozole and fulvestrant efficacy for postmenopausal, estrogen receptor-positive, human epidermal growth factor receptor 2-negative breast cancer patients: Results of the UNICANCER CARMINA 02 French trial (UCBG 0609)

BACKGROUND

Treatment strategies for locally advanced breast cancer in elderly patients too frail to receive neoadjuvant chemotherapy and the introduction of new classes of drugs in the early 2000s have led to the consideration of endocrine therapy as a neoadjuvant treatment for younger hormone receptor (HR)-positive, postmenopausal patients not eligible for primary breast-conserving surgery (BCS).

METHODS

This was a multicenter, phase 2, randomized trial designed to evaluate as its primary objective the clinical response rate after up to 6 months of neoadjuvant endocrine therapy (NET) alone in HR-positive/human epidermal growth factor receptor 2 (HER2)-negative patients with 1 mg of anastrozole (arm A) or 500 mg of fulvestrant (arm B). Secondary objectives included the BCS rate, tumor response assessment (breast ultrasound and magnetic resonance imaging), pathological response (Sataloff classification), safety profile, relapse-free survival (RFS), and predictive markers of responses and outcomes.

RESULTS

From October 2007 to April 2011, 116 women (mean age, 71.6 years) with operable infiltrating breast adenocarcinoma (T2-T4, N0-N3, M0) were randomized to receive anastrozole or fulvestrant. The clinical response rates at 6 months were 52.6% (95% confidence interval [CI], 41%-64%) in arm A and 36.8% (95% CI, 25%-49%) in arm B. BCS was performed for 57.6% of arm A patients and 50% of arm B patients. The RFS rates at 3 years were 94.9% in arm A and 91.2% in arm B. The Preoperative Endocrine Prognostic Index status was significantly predictive of RFS. Both treatments were well tolerated.

CONCLUSIONS

Both drugs are effective and well tolerated as NET in postmenopausal women with HR-positive/HER2-negative breast cancer. NET could be considered a treatment option in this subpopulation. Cancer 2016;122:3032-3040. © 2016 American Cancer Society.

Estrogen receptor alpha gene amplification in breast cancer: 25 years of debate

Twenty-five years ago, Nembrot and colleagues reported amplification of the estrogen receptor alpha gene (ESR1) in breast cancer, initiating a broad and still ongoing scientific debate on the prevalence and clinical significance of this genetic aberration, which affects one of the most important genes in breast cancer. Since then, a multitude of studies on this topic has been published, covering a wide range of divergent results and arguments. The reported prevalence of this alteration in breast cancer ranges from 0% to 75%, suggesting that ESR1 copy number analysis is hampered by technical and interpreter issues. To date, two major issues related to ESR1 amplification remain to be conclusively addressed: (1) The extent to which abundant amounts of messenger RNA can mimic amplification in standard fluorescence in situ hybridization assays in the analysis of strongly expressed genes like ESR1, and (2) the clinical relevance of ESR1 amplification: Such relevance is strongly disputed, with data showing predictive value for response as well as for resistance of the cancer to anti-estrogen therapies, or for subsequent development of cancers in the case of precursor lesions that display amplification of ESR1. This review provides a comprehensive summary of the various views on ESR1 amplification, and highlights explanations for the contradictions and conflicting data that could inform future ESR1 research.