Gene expression profiling and prediction of response to hormonal neoadjuvant treatment with anastrozole in surgically resectable breast cancer

Impact of Duration of Neoadjuvant Aromatase Inhibitors on Molecular Expression Profiles in Estrogen Receptor-positive Breast Cancers

PURPOSE

Aromatase inhibitor (AI) treatment is the standard of care for postmenopausal women with primary estrogen receptor-positive breast cancer. The impact of duration of neoadjuvant endocrine therapy (NET) on molecular characteristics is still unknown. We evaluated and compared changes of gene expression profiles under short-term (2-week) versus longer-term neoadjuvant AIs.

EXPERIMENTAL DESIGN

Global gene expression profiles from the PeriOperative Endocrine Therapy for Individualised Care (POETIC) trial (137 received 2 weeks of AIs and 47 received no treatment) and targeted gene expression from 80 patients with breast cancer treated with NET for more than 1 month (NeoAI) were assessed. Intrinsic subtyping, module scores covering different cancer pathways and immune-related genes were calculated for pretreated and posttreated tumors.

RESULTS

The differences in intrinsic subtypes after NET were comparable between the two cohorts, with most Luminal B (90.0% in the POETIC trial and 76.3% in NeoAI) and 50.0% of HER2 enriched at baseline reclassified as Luminal A or normal-like after NET. Downregulation of proliferative-related pathways was observed after 2 weeks of AIs. However, more changes in genes from cancer-signaling pathways such as MAPK and PI3K/AKT/mTOR and immune response/immune-checkpoint components that were associated with AI-resistant tumors and differential outcome were observed in the NeoAI study.

CONCLUSIONS

Tumor transcriptional profiles undergo bigger changes in response to longer NET. Changes in HER2-enriched and Luminal B subtypes are similar between the two cohorts, thus AI-sensitive intrinsic subtype tumors associated with good survival might be identified after 2 weeks of AI. The changes of immune-checkpoint component expression in early AI resistance and its impact on survival outcome warrants careful investigation in clinical trials.

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.

High gene expression of estrogen and progesterone receptors is associated with decreased t cell infiltration in patients with NSCLC

OBJECTIVES

Prior studies have demonstrated that signaling via the estrogen and progesterone receptors (ER and PR) may affect prognosis in non-small cell lung cancer (NSCLC). The precise impact of hormone signaling on clinical outcomes in NSCLC, especially in the context of immune checkpoint blockade, remains unclear.

MATERIALS AND METHODS

We obtained RNA-Seq data from The Cancer Genome Atlas (TCGA) to determine mRNA expression levels of ESR1 (ER-α), ESR2 (ER-β), PGR (PR), CYP19A1 (aromatase), and immune-related genes. Tumor infiltration by activated T cells was predicted based on expression of immune metagenes.

RESULTS

High levels of both ESR1 and PGR were associated with significantly decreased tumor infiltration by CD4+ and CD8+ activated T cells. CYP19A1 expression was associated with decreased CD4+ but not CD8+ T cell infiltration. There were no significant differences based on ESR2. These findings persisted after stratifying patients based on sex and tumor histology. In addition, increased ESR1 was associated with high gene expression of immune checkpoint markers, while increased PGR was associated with high levels of TGF-β genes. In a multivariate logistic regression analysis, ESR1, PGR, TGFB1, and the total number of somatic variants were identified as independent factors predicting T cell infiltration.

CONCLUSIONS

Increased gene expression of ER-α and PR was associated with decreased activated T cell infiltration in patients with NSCLC. The relevance of hormone receptor status should be validated clinically, including in the context of immune checkpoint inhibitors.

The immunomodulatory effects of endocrine therapy in breast cancer

Endocrine therapies with SERMs (selective estrogen receptor modulators) or SERDs (selective estrogen receptor downregulators) are standard therapies for patients with estrogen receptor (ER)-positive breast cancer. Multiple small molecule inhibitors targeting the PI3K-AKT-mTOR pathway or CDK4/6 have been developed to be used in combination with anti-estrogen drugs to overcome endocrine resistance. In addition to their direct antitumor effects, accumulating evidence has revealed the tumor immune microenvironment (TIM)-modulating effects of these therapeutic strategies, which have not been properly acknowledged previously. The immune microenvironment of breast tumors plays a crucial role in tumor development, metastasis and treatment response to endocrine therapy and immunotherapy. Therefore, in our current work, we comprehensively review the immunomodulatory effect of endocrine therapy and discuss its potential applications in combination with immune checkpoint inhibitors in breast cancer treatment.

Oral metronomic vinorelbine combined with endocrine therapy in hormone receptor-positive HER2-negative breast cancer: SOLTI-1501 VENTANA window of opportunity trial

Background

The biological effect of oral metronomic vinorelbine (mVNB) alone or in combination with endocrine therapy in patients with hormone receptor-positive (HR+)/HER2-negative breast cancer has been scarcely addressed.

Methods

Postmenopausal women with untreated stage I–III HR+/HER2-negative breast cancer were randomized (1:1:1) to receive 3 weeks of letrozole (LTZ) 2.5 mg/day, oral mVNB 50 mg 3 days/week, or the combination. The primary objective was to evaluate, within PAM50 Luminal A/B disease, if the anti-proliferative effect of LTZ+mVNB was superior to monotherapy. An anti-proliferative effect was defined as the mean relative decrease of the PAM50 11-gene proliferation score in combination arm vs. both monotherapy arms. Secondary objectives included the evaluation of a comprehensive panel of breast cancer-related genes and safety. An unplanned analysis of stromal tumor-infiltrating lymphocytes (sTILs) was also performed. PAM50 analyses were performed using the nCounter®-based Breast Cancer 360™ gene panel, which includes 752 genes and 32 signatures.

Results

Sixty-one patients were randomized, and 54 paired samples (89%) were analyzed. The main patient characteristics were mean age of 67, mean tumor size of 1.7 cm, mean Ki67 of 14.3%, stage I (55.7%), and grades 1–2 (90%). Most baseline samples were PAM50 Luminal A (74.1%) or B (22.2%). The anti-proliferative effect of 3 weeks of LTZ+mVNB (− 73.2%) was superior to both monotherapy arms combined (− 49.9%; p = 0.001) and mVNB (− 19.1%; p < 0.001). The anti-proliferative effect of LTZ+mVNB (− 73.2%) was numerically higher compared to LTZ (− 65.7%) but did not reach statistical significance (p = 0.328). LTZ+mVNB induced high expression of immune-related genes and gene signatures, including CD8 T cell signature and PDL1 gene and low expression of ER-regulated genes (e.g., progesterone receptor) and cell cycle-related and DNA repair genes. In tumors with ≤ 10% sTILs at baseline, a statistically significant increase in sTILs was observed following LTZ (paired analysis p = 0.049) and LTZ+mVNB (p = 0.012). Grade 3 adverse events occurred in 3.4% of the cases.

Conclusions

Short-term mVNB is well-tolerated and presents anti-proliferative activity alone and in combination with LTZ. The high expression of immune-related biological processes and sTILs observed with the combination opens the possibility of studying this combination with immunotherapy. Further investigation comparing these biological results with other metronomic schedules or drug combinations is warranted.

Trial registration

NCT02802748, registered 16 June 2016.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s13058-019-1195-z.

Neoadjuvant Therapy for Breast Cancer as a Model for Translational Research

Neoadjuvant therapy, where patients receive systemic therapy before surgical removal of the tumour, can downstage tumours allowing breast-conserving surgery, rather than mastectomy. In addition to its impact on surgery, the neoadjuvant setting offers a valuable opportunity to monitor individual tumour response. The effectiveness of standard and/or potential new therapies can be tested in the neoadjuvant pre-surgical setting. It can potentially help to identify markers differentiating patients that will potentially benefit from continuing with the same or a different adjuvant treatment enabling personalised treatment. Characterising the molecular response to treatment over time can more accurately identify the significant differences between baseline samples that would not be identified without post-treatment samples. In this review, we discuss the potential and challenges of using the neoadjuvant setting in translational breast cancer research, considering the implications for improving our understanding of response to treatment, predicting therapy benefit, modelling breast cancer dormancy, and the development of drug resistance.

Molecular profiling of hormone receptor-positive, HER2-negative breast cancers from patients treated with neoadjuvant endocrine therapy in the CARMINA 02 trial (UCBG-0609)

BACKGROUND

Postmenopausal women with large, hormone receptor (HR)-positive/HER2-negative and low-proliferative breast cancer derived a benefit from neoadjuvant endocrine therapy (NET) in the CARMINA02 trial. This study was designed to correlate gene expression and mutation profiles with both response to NET and prognosis.

METHODS

Gene expression profiling using RNA sequencing was performed in 86 pre-NET and post-NET tumor samples. Targeted next-generation sequencing of 91 candidate breast cancer-associated genes was performed on DNA samples from 89 patients. Molecular data were correlated with radiological response and relapse-free survival.

RESULTS

The transcriptional profile of tumors to NET in responders involved immune-associated genes enriched in activated Th1 pathway, which remained unchanged in non-responders. Immune response was confirmed by analysis of tumor-infiltrating lymphocytes (TILs). The percentage of TILs was significantly increased post-NET compared to pre-NET samples in responders (p = 0.0071), but not in non-responders (p = 0.0938). Gene expression revealed that lipid metabolism was the main molecular function related to prognosis, while PPARγ is the most important upstream regulator gene. The most frequently mutated genes were PIK3CA (48.3%), CDH1 (20.2%), PTEN (15.7%), TP53 (10.1%), LAMA2 (10.1%), BRCA2 (9.0%), MAP3K1 (7.9%), ALK (6.7%), INPP4B (6.7%), NCOR1 (6.7%), and NF1 (5.6%). Cell cycle and apoptosis pathway and PIK3CA/AKT/mTOR pathway were altered significantly more frequently in non-responders than in responders (p = 0.0017 and p = 0.0094, respectively). The average number of mutations per sample was significantly higher in endocrine-resistant tumors (2.88 vs. 1.64, p = 0.03), but no difference was observed in terms of prognosis. ESR1 hotspot mutations were detected in 3.4% of treatment-naive tumors.

CONCLUSIONS

The Th1-related immune system and lipid metabolism appear to play key roles in the response to endocrine therapy and prognosis in HR-positive/HER2-negative breast cancer. Deleterious somatic mutations in the cell cycle and apoptosis pathway and PIK3CA/AKT/mTOR pathway may be relevant for clinical management.

TRIAL REGISTRATION

This trial is registered with ClinicalTrials.gov ( NCT00629616 ) on March 6, 2008, retrospectively registered.

Neoadjuvant Endocrine Therapy in Breast Cancer Upregulates the Cytotoxic Drug Pump ABCG2/BCRP, and May Lead to Resistance to Subsequent Chemotherapy

INTRODUCTION

Neoadjuvant treatments for primary breast cancer are becoming more common; however, little is known about how these impact on response to subsequent adjuvant therapies. Conveniently, neoadjuvant therapy provides opportunities to consider this question, by studying therapy-induced expression changes using comparisons between pre- and posttreatment samples. These data are relatively lacking in the context of neoadjuvant endocrine therapy, as opposed to the more common neoadjuvant chemotherapy. Here, we investigate the relevance of expression of the xenobiotic transporter ABCG2/BCRP, a gene/protein associated with chemoresistance, in the context of neoadjuvant endocrine therapy and particularly with reference to subsequent chemotherapy treatment.

MATERIALS AND METHODS

ABCG2/BCRP expression was assessed by immunohistochemistry or by expression arrays in matched patient samples pre- and post-neoadjuvant endocrine therapy. Cell culture was used to model the impact of endocrine therapy-induced changes in ABCG2/BCRP on subsequent chemotherapy response, using Western blots, quantitative polymerase chain reaction, survival assays, and cell cycle analyses.

RESULTS

ABCG2/BCRP was commonly and significantly upregulated in breast cancers after treatment with neoadjuvant endocrine therapy in 3 separate cohorts encompassing a total of 200 patients. Treatment with the endocrine therapeutic tamoxifen similarly induced ABCG2/BCRP upregulation in a relevant model cell line, the estrogen receptor-positive line T47D. Critically, this upregulation was associated with significantly increased chemoresistance to subsequent treatment with epirubicin, an anthracycline commonly used in breast cancer adjuvant chemotherapy.

CONCLUSION

Our data suggest that neoadjuvant endocrine therapy may induce poor responses to adjuvant chemotherapy, and therefore, that clinical outcomes following this treatment sequence warrant further study.

Breast cancer Ki67 expression prediction by DCE-MRI radiomics features

AIM

To investigate whether quantitative radiomics features extracted from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) are associated with Ki67 expression of breast cancer.

MATERIALS AND METHODS

This institutional review board-approved retrospective study comprised 377 Chinese women who were diagnosed with invasive breast cancer in 2015. This cohort included 53 low-Ki67 expression (Ki67 proliferation index less than 14%) and 324 cases with high-Ki67 expression (Ki67 proliferation index more than 14%). A binary-classification of low-versus high- Ki67 expression was performed. A set of 56 quantitative radiomics features, including morphological, greyscale statistic, and texture features, were extracted from the segmented lesion area. Three machine learning classification methods, including naive Bayes, k-nearest neighbour and support vector machine, were employed for the classification and the least absolute shrink age and selection operator (LASSO) method was used to select most predictive features set for the classifiers. Classification performance was evaluated by the area under receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity.

RESULES

The model that used naive Bayes classification method achieved the best performance than the other two methods, yielding 0.773 AUC, 0.757 accuracy, 0.777 sensitivity and 0.769 specificity. Three most predictive features, i.e., contrast, entropy and line likeness, were selected by the LASSO method and showed a statistical significance (p<0.05) in the classification.

CONCLUSION

The present study showed that quantitative radiomics imaging features of breast tumour extracted from DCE-MRI are associated with breast cancer Ki67 expression. Future larger studies are needed in order to further evaluate the findings.

Targeting immune checkpoints in breast cancer: an update of early results

The immune tumour microenvironment has been shown to play a crucial role in the development and progression of cancer. Expression of gene signatures, reflecting immune activation, and the presence of tumour-infiltrating lymphocytes were associated with favourable outcomes in HER2-positive and triple-negative breast cancer. Recently, immunotherapy with immune checkpoint blockade induced long-lasting responses and improved survival in hard-to-treat malignancies (ie, melanoma and non-small cell lung cancer) and are changing treatment paradigms in a variety of neoplastic diseases. Immune checkpoint blockade has been evaluated in breast cancer, particularly in the triple-negative subtype, with promising results observed in monotherapy or in combination with chemotherapy in the metastatic and neoadjuvant settings. However, identification of patients who are most likely to benefit from immune checkpoint blockade remains challenging, with many patients not responding to treatments and a significant financial cost. The combination of immune checkpoint blockade with conventional cancer treatments such as chemotherapy, radiotherapy, targeted therapies or with other immunotherapies is a promising strategy to potentiate its efficacy in breast cancer although further research is required to effectively identify who will respond to these immunotherapies. In this review we report the most recent results that emerged from trials testing immune checkpoint blockade and potential predictive biomarkers and emphasise the new strategies that are under clinical development in breast cancer.

Sushi Domain-Containing Protein 3: A Potential Target for Breast Cancer

Aromatase inhibitors (AIs) are the most effective endocrine treatment for estrogen receptor α-positive (ERα+) postmenopausal breast cancer. Identification of biomarkers that are able to predict AIs responsiveness of patients is a key for successful treatment. The currently used biomarkers for tamoxifen responsiveness, which including ERα as well as progesterone receptor can only predict part of the potential responders to AIs treatment. Sushi domain-containing protein 3 (SUSD3) is a potential novel biomarker of AIs responsiveness. The lack of SUSD3 expression in breast cancer tissue can be an important predictor for non-responsiveness to AI. Here we reviewed the property and function of SUSD3, its usage as a biomarker and the practicability for SUSD3 to become a target for immune therapy. We suggest this protein can be potentially measured or targeted for prevention, diagnostic, and therapeutic purposes for estrogen or progesterone-dependent disorders including breast cancer in women.

Adaptation to AI Therapy in Breast Cancer Can Induce Dynamic Alterations in ER Activity Resulting in Estrogen-Independent Metastatic Tumors

PURPOSE

Acquired resistance to aromatase inhibitor (AI) therapy is a major clinical problem in the treatment of breast cancer. The detailed mechanisms of how tumor cells develop this resistance remain unclear. Here, the adapted function of estrogen receptor (ER) to an estrogen-depleted environment following AI treatment is reported.

EXPERIMENTAL DESIGN

Global ER chromatin immuno-precipitation (ChIP)-seq analysis of AI-resistant cells identified steroid-independent ER target genes. Matched patient tumor samples, collected before and after AI treatment, were used to assess ER activity.

RESULTS

Maintained ER activity was observed in patient tumors following neoadjuvant AI therapy. Genome-wide ER-DNA-binding analysis in AI-resistant cell lines identified a subset of classic ligand-dependent ER target genes that develop steroid independence. The Kaplan-Meier analysis revealed a significant association between tumors, which fail to decrease this steroid-independent ER target gene set in response to neoadjuvant AI therapy, and poor disease-free survival and overall survival (n = 72 matched patient tumor samples, P = 0.00339 and 0.00155, respectively). The adaptive ER response to AI treatment was highlighted by the ER/AIB1 target gene, early growth response 3 (EGR3). Elevated levels of EGR3 were detected in endocrine-resistant local disease recurrent patient tumors in comparison with matched primary tissue. However, evidence from distant metastatic tumors demonstrates that the ER signaling network may undergo further adaptations with disease progression as estrogen-independent ER target gene expression is routinely lost in established metastatic tumors.

CONCLUSIONS

Overall, these data provide evidence of a dynamic ER response to endocrine treatment that may provide vital clues for overcoming the clinical issue of therapy resistance. Clin Cancer Res; 22(11); 2765-77. ©2016 AACR.

Accurate Prediction and Validation of Response to Endocrine Therapy in Breast Cancer

PURPOSE

Aromatase inhibitors (AIs) have an established role in the treatment of breast cancer. Response rates are only 50% to 70% in the neoadjuvant setting and lower in advanced disease. Accurate biomarkers are urgently needed to predict response in these settings and to determine which individuals will benefit from adjuvant AI therapy.

PATIENTS AND METHODS

Pretreatment and on-treatment (after 2 weeks and 3 months) biopsies were obtained from 89 postmenopausal women who had estrogen receptor-alpha positive breast cancer and were receiving neoadjuvant letrozole for transcript profiling. Dynamic clinical response was assessed with use of three-dimensional ultrasound measurements.

RESULTS

The molecular response to letrozole was characterized and a four-gene classifier of clinical response was established (accuracy of 96%) on the basis of the level of two genes before treatment (one gene [IL6ST] was associated with immune signaling, and the other [NGFRAP1] was associated with apoptosis) and the level of two proliferation genes (ASPM, MCM4) after 2 weeks of therapy. The four-gene signature was found to be 91% accurate in a blinded, completely independent validation data set of patients treated with anastrozole. Matched 2-week on-treatment biopsies were associated with improved predictive power as compared with pretreatment biopsies alone. This signature also significantly predicted recurrence-free survival (P = .029) and breast cancer -specific survival (P = .009). We demonstrate that the test can also be performed with use of quantitative polymerase chain reaction or immunohistochemistry.

CONCLUSION

A four-gene predictive model of clinical response to AIs by 2 weeks has been generated and validated. Deregulated immune and apoptotic responses before treatment and cell proliferation that is not reduced 2 weeks after initiation of treatment are functional characteristics of breast tumors that do not respond to AIs.

Integrative analyses identify modulators of response to neoadjuvant aromatase inhibitors in patients with early breast cancer

INTRODUCTION

Aromatase inhibitors (AIs) are a vital component of estrogen receptor positive (ER+) breast cancer treatment. De novo and acquired resistance, however, is common. The aims of this study were to relate patterns of copy number aberrations to molecular and proliferative response to AIs, to study differences in the patterns of copy number aberrations between breast cancer samples pre- and post-AI neoadjuvant therapy, and to identify putative biomarkers for resistance to neoadjuvant AI therapy using an integrative analysis approach.

METHODS

Samples from 84 patients derived from two neoadjuvant AI therapy trials were subjected to copy number profiling by microarray-based comparative genomic hybridisation (aCGH, n=84), gene expression profiling (n=47), matched pre- and post-AI aCGH (n=19 pairs) and Ki67-based AI-response analysis (n=39).

RESULTS

Integrative analysis of these datasets identified a set of nine genes that, when amplified, were associated with a poor response to AIs, and were significantly overexpressed when amplified, including CHKA, LRP5 and SAPS3. Functional validation in vitro, using cell lines with and without amplification of these genes (SUM44, MDA-MB134-VI, T47D and MCF7) and a model of acquired AI-resistance (MCF7-LTED) identified CHKA as a gene that when amplified modulates estrogen receptor (ER)-driven proliferation, ER/estrogen response element (ERE) transactivation, expression of ER-regulated genes and phosphorylation of V-AKT murine thymoma viral oncogene homolog 1 (AKT1).

CONCLUSIONS

These data provide a rationale for investigation of the role of CHKA in further models of de novo and acquired resistance to AIs, and provide proof of concept that integrative genomic analyses can identify biologically relevant modulators of AI response.

One-Year Neoadjuvant Endocrine Therapy in Breast Cancer

The evaluation of the effects of 1-year endocrine therapy (NET) was aimed at. A retrospective analysis of 42 cases with 46 stage II-III invasive, hormone receptor-positive, HER2-negative breast cancers was performed. One-year NET was planned with letrozole (n = 33, postmenopausal group), or with goserelin plus letrozole (n = 7) or with goserelin plus tamoxifen (n = 2) (premenopausal group). Surgery was performed in accordance with the initial stage and the response to therapy. With regard to the tumor remaining in the surgical specimen, risk groups were constructed: Group 1: stage 0, pathological complete regression (pCR); Group 2: stages IA-IIA; Group 3: stages ≥ IIB + cases with clinical progression. Due to local progression, NET was replaced by neoadjuvant chemotherapy in three patients (four tumors). In two postmenopausal patients, letrozole was replaced by tamoxifen because of the insufficient treatment effect. In 19/42 cases, breast-conserving surgery was performed. Within Group 1, there was no cancer in four cases, while only DCIS remained in 2 (pCR: 13 %); Groups 2 and 3 comprised 25 and 15 cases, respectively. The likeliness of a good response (Groups 1 and 2 vs. Group 3) to NET was increased by 7 % for every 1 % increase of the expression of ER (OR = 1.070; 95 % CI: 1.007-1.138, p = 0.029). Progression-free survival differed according to treatment response (p = 0.001). The post-therapy Ki67 value of ≤ 15 % had only a marginal effect on survival. No other associations were detected between the tumor characteristics and the therapeutic response or survival. Long-duration NET is effective and safe in cases of hormone-sensitive breast cancer.

17β-estradiol regulates giant vesicle formation via estrogen receptor-alpha in human breast cancer cells

A significant proportion of the genes regulated by 17-beta-estradiol (E2) via estrogen receptor alpha (ERα) have roles in vesicle trafficking in breast cancer. Intracellular vesicle trafficking and extracellular vesicles have important roles in tumourigenesis. Here we report the discovery of giant (3-42μm) intracellular and extracellular vesicles (GVs) and the role of E2 on vesicle formation in breast cancer (BC) cell lines using three independent live cell imaging techniques. Large diameter vesicles, GVs were also identified in a patient-derived xenograft BC model, and in invasive breast carcinoma tissue. ERα-positive (MCF-7 and T47D) BC cell lines demonstrated a significant increase in GV formation after stimulation with E2 which was reversed by tamoxifen. ERα-negative (MDA-MB-231 and MDA-MB-468) BC cell lines produced GVs independently of E2 and tamoxifen. These results indicate the existence of both intracellular and extracellular vesicles with considerably larger dimensions than generally recognised with BC cells and suggest that the GVs are regulated by E2 via ERα in ERα-positive BC but by E2-independent mechanisms in ER-ve BC.

Dual roles for immune metagenes in breast cancer prognosis and therapy prediction

BACKGROUND

Neoadjuvant chemotherapy for breast cancer leads to considerable variability in clinical responses, with only 10 to 20% of cases achieving complete pathologic responses (pCR). Biological and clinical factors that determine the extent of pCR are incompletely understood. Mounting evidence indicates that the patient's immune system contributes to tumor regression and can be modulated by therapies. The cell types most frequently observed with this association are effector tumor infiltrating lymphocytes (TILs), such as cytotoxic T cells, natural killer cells and B cells. We and others have shown that the relative abundance of TILs in breast cancer can be quantified by intratumoral transcript levels of coordinately expressed, immune cell-specific genes. Through expression microarray analysis, we recently discovered three immune gene signatures, or metagenes, that appear to reflect the relative abundance of distinct tumor-infiltrating leukocyte populations. The B/P (B cell/plasma cell), T/NK (T cell/natural killer cell) and M/D (monocyte/dendritic cell) immune metagenes were significantly associated with distant metastasis-free survival of patients with highly proliferative cancer of the basal-like, HER2-enriched and luminal B intrinsic subtypes.

METHODS

Given the histopathological evidence that TIL abundance is predictive of neoadjuvant treatment efficacy, we evaluated the therapy-predictive potential of the prognostic immune metagenes. We hypothesized that pre-chemotherapy immune gene signatures would be significantly predictive of tumor response. In a multi-institutional, meta-cohort analysis of 701 breast cancer patients receiving neoadjuvant chemotherapy, gene expression profiles of tumor biopsies were investigated by logistic regression to determine the existence of therapy-predictive interactions between the immune metagenes, tumor proliferative capacity, and intrinsic subtypes.

RESULTS

By univariate analysis, the B/P, T/NK and M/D metagenes were all significantly and positively associated with favorable pathologic responses. In multivariate analyses, proliferative capacity and intrinsic subtype altered the significance of the immune metagenes in different ways, with the M/D and B/P metagenes achieving the greatest overall significance after adjustment for other variables.

CONCLUSIONS

Gene expression signatures of infiltrating immune cells carry both prognostic and therapy-predictive value that is impacted by tumor proliferative capacity and intrinsic subtype. Anti-tumor functions of plasma B cells and myeloid-derived antigen-presenting cells may explain more variability in pathologic response to neoadjuvant chemotherapy than previously recognized.

Regulation of aromatase expression in breast cancer treated with anastrozole neoadjuvant therapy

Aromatase inhibitors (AIs), such as anastrozole, are established in the treatment of hormone-dependent breast cancer. However, ∼20% of patients with hormone receptor-positive breast tumors treated with anastrozole do not respond and it remains impossible to accurately predict sensitivity. Since polymorphisms in the aromatase gene may influence the response to inhibitory drugs, we evaluated the presence of rs6493497 and rs7176005 polymorphisms (mapping in the 5′-flanking region of the CYP19A1 gene coding for the aromatase protein) in a cohort of 37 patients with postmenopausal breast cancer who received three-month neoadjuvant treatment with anastrozole. We then investigated any association of the polymorphisms with changes in aromatase mRNA expression change and/or response to treatment. We also analyzed five miRNAs computationally predicted to target aromatase, to observe any association between their expression and sensitivity to anastrozole. Three samples carried the two polymorphisms and the remaining samples were wild-type for both, however, no association with response or with aromatase mRNA basal expression level or expression difference after therapy was observed. Polymorphic samples that were resistant to anastrozole showed no change or decrease in aromatase expression following AI treatment, whereas an increase in expression was observed for the polymorphic responsive samples. No statistically significant correlation was observed between miRNA and aromatase mRNA expression, or with response to anastrozole neoadjuvant treatment. These data indicate that the polymorphisms analyzed are not involved in aromatase activity and that other epigenetic mechanisms may regulate aromatase protein expression.

Molecular pathways: involvement of immune pathways in the therapeutic response and outcome in breast cancer

The immune system could mediate the antitumor activity of several anticancer treatments. Several chemotherapy compounds, including anthracyclines and oxaliplatin, induce immunogenic cell death that in turn activates antitumor immune response. Trastuzumab induces antibody-dependant cell-mediated cytotoxicity. On the basis of this background, immune markers have recently been the focus of intense translational research to predict and monitor the efficacy of treatments. Gene expression arrays and immunohistochemistry have assessed immune activation and infiltration by macrophages, natural killer, and T and B lymphocytes. Using these approaches, several retrospective analyses of large trials have shown that activation of immune pathway may predict treatment efficacy and outcome in patients with breast cancers. As examples, intratumoral infiltration by lymphocytes and interferon-response in primary tumor predicted the efficacy of neoadjuvant chemotherapy. Intratumoral infiltration by lymphocytes was associated with good prognosis in patients with triple-negative breast cancer treated with adjuvant chemotherapy. More recently, it has been suggested that lymphocyte infiltration could also predict efficacy of trastuzumab. Finally, small retrospective studies have suggested that postchemotherapy lymphocyte infiltrates could be associated with better outcome in patients who did not reach pathologic complete response. This body of evidence suggests that assessing immune infiltration and activation could be useful in the future to stratify breast cancer patients. In addition, they provide evidence for the development of immunotherapies in breast cancer patients.

Immunomodulatory effects of anti-estrogenic drugs

There are substantial experimental, epidemiological and clinical evidences that show that breast cancer pathology is influenced by endogenous estrogens. This knowledge is the foundation upon which endocrine deprivation therapy has been developed as a major modality for the management of breast cancer. Tamoxifen, which functions as a competitive partial agonist-inhibitor of estrogen at its receptor, has been widely used for more than three decades for adjuvant endocrine treatment in breast cancer. Currently, other effective drugs for endocrine therapy include raloxifene, different aromatase inhibitors (particularly third-generation agents) and luteinizing hormone-releasing hormone agonists. In recent years, a growing body of evidence suggests that these drugs can also act as immune modulators by altering the function of various leukocytes and the release of different cytokines. Moreover, there is evidence that anti-estrogens may prove to be beneficial in the treatment or prevention of some autoimmune diseases due to their effects on immune function. However, their immunopharmacological aspects in the present state of knowledge are not precisely comprehensible. Only a clear pathophysiological understanding could lead to an efficient strategy for breast cancer prevention and decrease in the mortality due to this disease.

Clinical relevance of Ki67 gene expression analysis using formalin-fixed paraffin-embedded breast cancer specimens

BACKGROUND

Ki67 is a protein associated with cell cycle activity and shows a good correlation with the growth fraction, which has been proposed as a prognostic or predictive marker in breast cancer. In this study, we aimed to analyze the expression levels of Ki67 (MKI67) messenger RNA (mRNA) derived from formalin-fixed paraffin-embedded (FFPE) tissues for comparison with the immunohistochemical Ki67 labeling index, and investigate the correlation coefficients with clinical outcomes.

METHODS

We analyzed the data of Ki67 mRNA from FFPE and matched fresh-frozen (FF) tissues based on a real-time quantitative reverse-transcription polymerase chain reaction (RT-qPCR) assay system in 203 cases of primary invasive breast cancer.

RESULTS

The correlation between Ki67 mRNA expression of either FFPE or FF specimens and Ki67 labeling index was positive, as was the correlation between the FFPE and FF results (P < 0.0001). Ki67 mRNA expression of FFPE specimens was significantly associated with clinicopathological characteristics: tumor size, lymph node status, nuclear grade, hormone receptors, human epidermal growth factor receptor 2 (Her2) status, and tumor subtype. In prognostic results, Ki67 gene expression in the FFPE specimens revealed almost similar patterns of significance in Kaplan-Meier curves and univariate and multivariate relapse-free survival results as the Ki67 labeling index.

CONCLUSIONS

Gene expression analysis of Ki67 of FFPE specimens could be successfully performed using RT-qPCR, closely resembling the significant clinical characteristics of Ki67 labeling index. These results confirm that Ki67 gene expression of FFPE specimens has potential for evaluation of cell cycle activity of breast cancer specimens.

Understanding the mechanisms of aromatase inhibitor resistance

Aromatase inhibitors (AIs) have a central role in the treatment of breast cancer; however, resistance is a major obstacle to optimal management. Evidence from endocrine, molecular and pathological measurements in clinical material taken before and after therapy with AIs and data from clinical trials in which AIs have been given as treatment either alone or in combination with other targeted agents suggest diverse causes for resistance. These include inherent tumour insensitivity to oestrogen, ineffective inhibition of aromatase, sources of oestrogenic hormones independent of aromatase, activation of signalling by non-endocrine pathways, enhanced cell survival and selection of hormone-insensitive cellular clones during treatment.

Early operable breast cancer in elderly women treated with an aromatase inhibitor letrozole as sole therapy

BACKGROUND

Primary endocrine therapy (PET) with aromatase inhibitors (AIs) is an option in elderly patients unfit for or unwilling to undergo surgery. We studied the outcome of patients treated with letrozole as PET.

METHODS

Patients with early oestrogen receptor (ER)/progesterone receptor (PR)-positive breast cancer treated with letrozole from February 2001 to September 2009 were reviewed. Inoperable and locally advanced tumours were excluded. Reasons for offering PET, response, survival, cause of death, time to initial and best response, fracture incidence, and late failure rates were studied.

RESULTS

In all, 104 patients received PET due to frailty (n=48), comorbidity (n=30), old age (n=9), and patient preference (n=17). Median follow-up was 56 months (4-106). Eighty-five cancers responded to letrozole (stable disease (SD, n=19), reduction in size (PR, n=42), and complete response ((CR), n=24)). Median survival was 51 months (4-103), time to initial response (PR/CR) 4.5 months (2-24), and time to best response 8.5 months (3-50). Letrozole was stopped in 25 patients due to progressive disease (n=19), side effects (n=5), and patient choice (n=1). Only 12 of 49 deaths were from breast cancer.

CONCLUSION

Letrozole is a reasonable alternative in elderly women with early ER/PR-positive invasive breast cancer who are unfit or unwilling to undergo standard therapy.

Molecular effects of oestrogen deprivation in breast cancer

This paper reviews the effects of oestrogen deprivation by third generation aromatase inhibitors on molecular profiles in breast cancers. It particularly focuses on results obtained as a result of pre-operative and neoadjuvant therapy in which primary breast cancers have been biopsied or excised before and during treatment with letrozole, anastrozole or exemestane. Studies may be subdivided into those evaluating early (10-14 days) or late (3-4 months) changes; a single investigation charted sequential changes. Early changes involved downregulation of genes classically induced by oestrogen or associated with cell cycle and proliferation. In contrast, expressions of genes associated with stromal signatures were upregulated. Considerably more genes were changed at later time-points; these probably represent not only primary effects on cellular expression but secondary consequences of cell death and clonal selection. Thus, after 3-4 months of treatment mitochondrial-related genes and those associated with cell cycle and cell division were downregulated whereas genes associated with extracellular matrix (ECM) remodelling, vascularization, inflammatory responses and cell adhesion were upregulated. Recently, observations have been reported from a study in which tumours were sequentially sampled to include pretreatment and both early and later time-points. This allowed direct monitoring of the dynamic changes in gene expression. Different patterns of changes in gene expression were identified which were also associated with general differences in sub-cellular distribution of corresponding proteins. The effect of treatment on expression of specific genes and processes such as aromatase, oestrogen receptor (ER), oestrogen-regulated genes, HER2, p53, ribosomal proteins, markers of proliferation, oxidative phosphorylation and stromal response are summarized.

Differentially expressed genes in window trials are influenced by the wound-healing process: lessons learned from a pilot study with anastrozole

BACKGROUND

Perioperative window trials provide an opportunity to obtain intact tumor samples at two different time-points for evaluation of potential surrogate biomarkers. We report results of a pilot trial designed to determine if treatment-mediated changes in gene expression can be detected in formalin-fixed paraffin-embedded (FFPE) samples after 10-d exposure to anastrozole in estrogen receptor (ER)-positive breast cancer compared with untreated controls.

METHODS

Paired tumor samples (biopsy, surgical) were obtained from 26 postmenopausal women with ER-positive breast cancer. Patients were assigned anastrozole (1 mg/d) for 10 d immediately prior to surgery (13 cases) or no treatment (13 controls). Five hundred two cancer-related genes were examined by the Illumina cDNA-mediated annealing, selection, extension, and ligation, FFPE cDNA array (moderated t-test, P ≤ 0.005). Surrogate biomarkers reflecting changes in gene expression were examined by immunohistochemistry (Wilcoxon rank-based test, P < 0.05).

RESULTS

Sufficient RNA was available from 19 paired samples (8 controls, 11 cases). Frozen tissue and FFPE showed good correlation (r = 0.82). Within each group, 18 genes, reflecting roles in proliferation, angiogenesis, and apoptosis, showed differential expression from biopsy to surgery (P < 0.005). Estrogen-related genes were dysregulated in the treated group only. A reduction in Ki-67 was observed in 7 (54%) treated cases and in 1 (7.7%) control patient.

CONCLUSIONS

10-d exposure to anastrozole resulted in dysregulation of 18/502 cancer-related genes, and Ki-67 was reduced in 54% of cases. FFPE samples demonstrated good correlation with frozen samples. However, changes in gene expression and increased Ki-67 in the control group suggest local effects of wound healing may represent a confounding factor in the interpretation of perioperative window trials.

ESR1 is co-expressed with closely adjacent uncharacterised genes spanning a breast cancer susceptibility locus at 6q25.1

Approximately 80% of human breast carcinomas present as oestrogen receptor α-positive (ER+ve) disease, and ER status is a critical factor in treatment decision-making. Recently, single nucleotide polymorphisms (SNPs) in the region immediately upstream of the ER gene (ESR1) on 6q25.1 have been associated with breast cancer risk. Our investigation of factors associated with the level of expression of ESR1 in ER+ve tumours has revealed unexpected associations between genes in this region and ESR1 expression that are important to consider in studies of the genetic causes of breast cancer risk. RNA from tumour biopsies taken from 104 postmenopausal women before and after 2 weeks treatment with an aromatase (oestrogen synthase) inhibitor was analyzed on Illumina 48K microarrays. Multiple-testing corrected Spearman correlation revealed that three previously uncharacterized open reading frames (ORFs) located immediately upstream of ESR1, C6ORF96, C6ORF97, and C6ORF211 were highly correlated with ESR1 (Rs =  0.67, 0.64, and 0.55 respectively, FDR<1 × 10(-7)). Publicly available datasets confirmed this relationship in other groups of ER+ve tumours. DNA copy number changes did not account for the correlations. The correlations were maintained in cultured cells. An ERα antagonist did not affect the ORFs' expression or their correlation with ESR1, suggesting their transcriptional co-activation is not directly mediated by ERα. siRNA inhibition of C6ORF211 suppressed proliferation in MCF7 cells, and C6ORF211 positively correlated with a proliferation metagene in tumours. In contrast, C6ORF97 expression correlated negatively with the metagene and predicted for improved disease-free survival in a tamoxifen-treated published dataset, independently of ESR1. Our observations suggest that some of the biological effects previously attributed to ER could be mediated and/or modified by these co-expressed genes. The co-expression and function of these genes may be important influences on the recently identified relationship between SNPs in this region and breast cancer risk.

Tamoxifen in early-stage estrogen receptor-positive breast cancer: overview of clinical use and molecular biomarkers for patient selection

Tamoxifen was the first targeted anticancer agent for breast cancer patients and its effects on reduction of breast cancer events and improvement in overall survival are undisputed. Hence, it has long been considered an essential part of patient care. Recent results of several large adjuvant hormonal trials evaluating the use of aromatase inhibitors in comparison with the previous standard of five years of tamoxifen has led to a paradigm shift, ensuring the inclusion of an aromatase inhibitor as part of standard endocrine therapy for most postmenopausal women diagnosed today with estrogen receptor-positive breast cancer. However, one could argue that despite statistically significant improvements in breast cancer events, an overall survival advantage has not been clear. In this review, we discuss recent genomic and molecular data pertaining to estrogen receptor-positive breast cancer and how this knowledge may aid clinicians to prescribe adjuvant hormonal treatment in the future. A combination of gene expression and genetic aberration markers may be most useful in discerning a population that is still appropriate for adjuvant tamoxifen treatment.