Cell State Transitions and Phenotypic Heterogeneity in Luminal Breast Cancer Implicating MicroRNAs as Potential Regulators

Luminal breast cancer subtypes respond poorly to endocrine and trastuzumab treatments due to cellular heterogeneity arising from the phenotype transitions, accounted for mainly by the loss of receptor expression. The origins of basal-like and human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer subtypes have been attributed to genetic and protein modifications in stem-like cells and luminal progenitor cell populations, respectively. The post-transcriptional regulation of protein expression is known to be influenced by microRNAs (miRNAs) that are deemed to be master regulators of several biological processes in breast tumorigenesis and progression. Our objective was to identify the fractions of luminal breast cancer cells that share stemness potentials and marker profiles and to elucidate the molecular regulatory mechanism that drives transitions between fractions, leading to receptor discordances. Established breast cancer cell lines of all prominent subtypes were screened for the expression of putative cancer stem cell (CSC) markers and drug transporter proteins using a side population (SP) assay. Flow-cytometry-sorted fractions of luminal cancer cells implanted in immunocompromised mice generated a pre-clinical estrogen receptor alpha (ERα+) animal model with multiple tumorigenic fractions displaying differential expression of drug transporters and hormone receptors. Despite an abundance of estrogen receptor 1 (ESR1) gene transcripts, few fractions transitioned to the triple-negative breast cancer (TNBC) phenotype with a visible loss of ER protein expression and a distinct microRNA expression profile that is reportedly enriched in breast CSCs. The translation of this study has the potential to provide novel therapeutic miRNA-based targets to counter the dreaded subtype transitions and the failure of antihormonal therapies in the luminal breast cancer subtype.

Revisiting Epithelial Carcinogenesis

The origin of cancer remains one of the most important enigmas in modern biology. This paper presents a hypothesis for the origin of carcinomas in which cellular aging and inflammation enable the recovery of cellular plasticity, which may ultimately result in cancer. The hypothesis describes carcinogenesis as the result of the dedifferentiation undergone by epithelial cells in hyperplasia due to replicative senescence towards a mesenchymal cell state with potentially cancerous behavior. In support of this hypothesis, the molecular, cellular, and histopathological evidence was critically reviewed and reinterpreted when necessary to postulate a plausible generic series of mechanisms for the origin and progression of carcinomas. In addition, the implications of this theoretical framework for the current strategies of cancer treatment are discussed considering recent evidence of the molecular events underlying the epigenetic switches involved in the resistance of breast carcinomas. The hypothesis also proposes an epigenetic landscape for their progression and a potential mechanism for restraining the degree of dedifferentiation and malignant behavior. In addition, the manuscript revisits the gradual degeneration of the nonalcoholic fatty liver disease to propose an integrative generalized mechanistic explanation for the involution and carcinogenesis of tissues associated with aging. The presented hypothesis might serve to understand and structure new findings into a more encompassing view of the genesis of degenerative diseases and may inspire novel approaches for their study and therapy.

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

Purpose

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

Methods

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

Results

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

Conclusion

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

Supplementary Information

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

Phenotype Discordance between Primary Tumor and Metastasis Impacts Metastasis Site and Outcome: Results of WSG-DETECT-PriMet

Introduction

Tumor biological factors of breast cancer (BC) such as hormone receptor (HR) status, HER2 status, and grade can differ in the metastatic cascade from primary to lymph node (LN) metastasis and to distant metastatic tissue. Systematic data regarding therapeutic consequences are yet limited.

Methods

We conducted a prospectively planned, retrospective cohort study comparing BC phenotype in tissue from primary tumors (PTs), locoregional LN metastases, and disease recurrence (DR). HR and HER2 as well as tumor grade in PTs and DR were obtained by a database search. No centralized biomarker testing was performed. The impact of changes in tumor biological factors on post-recurrence survival (PRS) and overall survival was analyzed.

Results

PriMet comprises 635 patients (LN tissue in 142 patients). Discrepancies for HR or HER2 status between PT and DR were observed in 18.7 and 21.6% of cases, respectively. For HR status, positivity of PT and negativity of DR was seen more often (13.2%) than vice versa (5.5%). For HER2 status, negativity of the primary and positivity of DR was seen more often (14.9%) than vice versa (6.7%). Discordance was more often observed between PT and LN metastasis compared to LN versus DR. However, numbers were small. Compared to concordant non-triple-negative (TN) disease, concordant TN disease showed significantly inferior PRS.

Conclusion

We demonstrate receptor discordance to occur relatively frequently between PT, LN metastasis, and DR and to impact patient prognosis. However, clinical consequences of receptor discordance need to be drawn with caution considering clinical aspects as well as tumor biology.

YAP, CTGF and Cyr61 are overexpressed in tamoxifen-resistant breast cancer and induce transcriptional repression of ERα

About 70% of breast cancers overexpress estrogen receptor α (ERα, encoded by ESR1). Tamoxifen, a competitive inhibitor of estrogen that binds to ER, has been widely used as a treatment for ER-positive breast cancer. However, 20-30% of breast cancer is resistant to tamoxifen treatment. The mechanisms underlying tamoxifen resistance remain elusive. We found that Yes-associated protein (YAP; also known as YAP1), connective tissue growth factor (CTGF; also known as CCN2) and cysteine-rich angiogenic inducer 61 (Cyr61; also known as CCN1) are overexpressed, while ERα is downregulated in tamoxifen-resistant breast cancer. Inhibition of YAP, CTGF and Cyr61 restored ERα expression and increased sensitivity to tamoxifen. Overexpression of YAP, CTGF, and Cyr61 led to downregulation of ERα and conferred resistance to tamoxifen in ER-positive breast cancer cells. Mechanistically, CTGF and Cyr61 downregulated ERα expression at the transcriptional level by directly binding to the regulatory regions of the ERα-encoding gene, leading to increased tamoxifen resistance. Also, CTGF induced Glut3 (also known as SLC2A3) expression, leading to increased glycolysis, which enhanced cell proliferation and migration in tamoxifen-resistant cells. Together, these results demonstrate a novel role of YAP, CTGF and Cyr61 in tamoxifen resistance and provide a molecular basis for their function in tamoxifen-resistant breast cancer.

Receptor Discordance of Metastatic Breast Cancer Depending on the Molecular Subtype

Introduction

Almost 30% of all women with early-stage breast cancer develop metastases. Treatment of metastatic disease is often based on the immunohistochemical information of the primary tumor, despite possible discordance of the hormone and Her2 receptor status.

Objectives

The aim of this study was to compare the receptor status of the primary tumor with the metastasis, and to evaluate for receptor discordance with regard to the molecular subtype, receptor status, and the localization of the metastases.

Methods

We retrospectively analyzed the data of all consecutive women with metastatic breast cancer, who underwent treatment at the Medical University Vienna between 2009 and 2016. Associations were calculated using the χ²or Fisher's exact test; years from primary diagnosis to metastatic disease were calculated using the Kaplan-Meier method.

Results

We identified 213 metastatic breast cancer patients, of whom 67 (31.5%) showed a discordant receptor status. Out of 32 patients with luminal A subtype, 14 (43.8%) had a switch of at least one receptor; 27 of 53 patients (50.9%) with luminal B subtype and 21 of 32 patients (65.6%) with Her2+ subtype showed receptor discordance; for triple-negative disease, 5 of 19 patients (36.3%) had a switch of at least one receptor. In 63 samples of bone metastases, 13 (20.6%) had discordant estrogen receptor status (p = 0.04). In 55 samples of bone metastases, 35 (63.3%) had discordant Her2 status (p = 0.002).

Conclusions

Our data show high rates of receptor discordance in metastatic breast cancer. Apart from the primary tumor, the immunohistochemical receptor status of the metastasis needs to be verified. This can lead to a change in treatment and prognosis.

Triple-negative breast cancer with calcified metastases of hepatic, portal vein and inferior vena cava: Report of a case and review of the literature

Breast cancer frequently metastasizes to the liver and this usually bears a poor prognosis. Complete calcifications of hepatic, portal vein and inferior vena cava (IVC) metastases from breast cancer after systemic chemotherapy is extremely rare and to our knowledge, has never been reported. It is important for physicians to recognize the pattern and the formation of calcified liver metastases because the radiographic features of calcifications may assist in differentiating the etiologies of underlying malignancies and provide prognostic significance. We here presented such a case of triple negative breast cancer (TNBC) with calcified liver, portal vein and IVC metastases, and reviewed the literature.

The Prognostic Impact of Hormonal Receptor and HER-2 Expression Discordance in Metastatic Breast Cancer Patients

Background

Hormone receptor (HR) and human epidermal growth factor receptor (HER2) discordance between primary and metastatic breast cancer lesions is common. However, its impact on long-term survival remains unclear. We aimed to determine the prognostic value of this discordance in patients with metastaticf breast cancer (MBC).

Methods

A total of 270 patients with MBC who were underwent re-biopsy of progressive metastases at Zhejiang Cancer Hospital from January 1, 2012 to December 31, 2015 with patients consent and then review their primary tumors pathological findings. The HR and HER2 status in both primary and progressive metastatic lesions was determined by immunohistochemistry and/or fluorescence in situ hybridization. The discordance rates were correlated with the clinicopathologic characteristics, metastatic lesions, salvage treatment, and survival analysis in this population.

Results

A total of 142 (52.6%) MBC patients were diagnosed with discordant HR and HER2 status. Alterations in estrogen receptor (ER), progesterone receptor (PR), and HER2 status were observed in 20.70%, 37.78%, and 11.48% cases, respectively. Chemotherapy (P=0.0192) and endocrine therapy (P=0.048) significantly affected the conversion of HR status. Endocrine therapy was positively correlated with PR discordance (P=0.002), while ER discordance was associated with adjuvant chemotherapy (P=0.031). Survival analysis showed that ER status alterations between primary and metastatic lesions were associated with overall survival (P=0.002). The clinical prognosis was significantly worse with HR losses than with persistent HR positivity (P=0.023). In Cox multivariate analysis, the loss of HR expression and conversion to triple negative were independent prognostic indicators.

Conclusion

Discordance in HR status between primary and metastatic lesions may impact the prognosis of MBC, and HR conversion has independent prognostic value.

Circulating tumor cells in metastatic breast cancer: clinical relevance and biological potential

PURPOSE OF REVIEW

The possibility of tumor dissemination through the blood system has been known for years. Circulating tumor cells (CTCs) are detectable in the peripheral blood of patients with early as well as metastatic breast cancer. The prognostic relevance of this biomarker has already been described. By the use of repeated blood sampling along the course of disease, CTCs can be monitored in terms of a regular 'liquid biopsy'. This review aims to summarize recent research findings and actual ongoing clinical studies to demonstrate the actual and future relevance of CTCs in daily clinical routine.

RECENT FINDINGS

Recent research results show that additional molecular analysis of CTCs might be helpful in gaining information about tumor characteristics, tumor heterogeneity and possible therapy resistance. Repetitive invasive core biopsies might be avoided.

SUMMARY

The assessment of molecular attributes may be indispensable for obtaining an optimized and personalized therapy aiming at extended survival and/or improved quality of life.

Biomarker discordance between primary breast cancer and bone or bone marrow metastases

BACKGROUND

Discordance in biomarker expression between primary and metastatic tumor sites has been reported in several studies; yet, few have examined this feature in bone lesions.

METHODS

We retrospectively enrolled patients with breast cancer metastasis to the bone or bone marrow, excluding cases where samples from both the primary and metastatic lesions were not available. Expression patterns of the estrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor receptor 2 (HER2) and Ki67 were compared in primary tumors and bone or bone marrow lesions.

RESULTS

Forty-six patients with a median age of 52 years (range, 34-72 years) were included in the study. Discordant rates of ER, PgR and HER2 were 20%, 46% and 0%, respectively. Physicians usually determined treatment options considering the results of biomarker re-evaluation. It is unlikely that biomarker discordance was related to prior treatment.

CONCLUSIONS

Biomarker discordance in bone or bone marrow lesions is common in patients with breast cancer. An accurate and thorough analysis of biomarkers and metastatic tumor properties is important for clinical decision-making.

Circulating Tumour Cells, Circulating Tumour DNA and Circulating MicroRNA in Metastatic Breast Carcinoma - What is the Role of Liquid Biopsy in Breast Cancer?

Dissemination of tumour cells and the development of solid metastases occurs via blood vessels and lymphatics. Circulating tumour cells (CTCs) and circulating tumour DNA (ctDNA) can be detected in venous blood in patients with early and metastatic breast cancer, and their prognostic relevance has been demonstrated on numerous occasions. Repeated testing for CTCs and ctDNA, or regular so-called "liquid biopsy", can be performed easily at any stage during the course of disease. Additional molecular analysis allows definition of tumour characteristics and heterogeneity that may be associated with treatment resistance. This in turn makes personalised, targeted treatments possible that may achieve both improved overall survival and quality of life.

89Zr-Lumretuzumab PET Imaging before and during HER3 Antibody Lumretuzumab Treatment in Patients with Solid Tumors

Purpose: We evaluated biodistribution and tumor targeting of ⁸⁹Zr-lumretuzumab before and during treatment with lumretuzumab, a human epidermal growth factor receptor 3 (HER3)-targeting monoclonal antibody.Experimental Design: Twenty patients with histologically confirmed HER3-expressing tumors received ⁸⁹Zr-lumretuzumab and underwent positron emission tomography (PET). In part A, ⁸⁹Zr-lumretuzumab was given with additional, escalating doses of unlabeled lumretuzumab, and scans were performed 2, 4, and 7 days after injection to determine optimal imaging conditions. In part B, patients were scanned following tracer injection before (baseline) and after a pharmacodynamic (PD)-active lumretuzumab dose for saturation analysis. HER3 expression was determined immunohistochemically in skin biopsies. Tracer uptake was calculated as standardized uptake value (SUV).Results: Optimal PET conditions were found to be 4 and 7 days after administration of ⁸⁹Zr-lumretuzumab with 100-mg unlabeled lumretuzumab. At baseline using 100-mg unlabeled lumretuzumab, the tumor SUVmax was 3.4 (±1.9) at 4 days after injection. SUVmean values for normal blood, liver, lung, and brain tissues were 4.9, 6.4, 0.9 and 0.2, respectively. Saturation analysis (n = 7) showed that 4 days after lumretuzumab administration, tumor uptake decreased by 11.9% (±8.2), 10.0% (±16.5), and 24.6% (±20.9) at PD-active doses of 400, 800, and 1,600 mg, respectively, when compared with baseline. Membranous HER3 was completely downregulated in paired skin biopsies already at and above 400-mg lumretuzumab.Conclusions: PET imaging showed biodistribution and tumor-specific ⁸⁹Zr-lumretuzumab uptake. Although, PD-active lumretuzumab doses decreased ⁸⁹Zr-lumretuzumab uptake, there was no clear evidence of tumor saturation by PET imaging as the tumor SUV did not plateau with increasing doses. Clin Cancer Res; 23(20); 6128-37. ©2017 AACR.

Molecular Concordance Between Primary Breast Cancer and Matched Metastases

Clinical management of breast cancer is increasingly personalized and based on molecular profiling. Often, primary tumors are used as proxies for systemic disease at the time of recurrence. However, recent studies have revealed substantial discordances between primary tumors and metastases, both with respect to traditional clinical treatment targets and on the genomic and transcriptomic level. With the increasing use of molecularly targeted therapy, discordance of actionable molecular targets between primary tumors and recurrences can result in nonoptimal treatment or unnecessary side effects. The purpose of this review is to illuminate the extent of cancer genome evolution through disease progression and the degree of molecular concordance between primary breast cancers and matched metastases. We present an overview of the most prominent studies investigating the expression of endocrine receptors, transcriptomics, and genome aberrations in primary tumors and metastases. In conclusion, biopsy of metastatic lesions at recurrence of breast cancer is encouraged to provide optimal treatment of the disease. Furthermore, molecular profiling of metastatic tissue provides invaluable mechanistic insight into the biology underlying metastatic progression and has the potential to identify novel, potentially druggable, drivers of progression.

Survival of breast cancer patients according to changes in expression of selected markers between primary tumor and lymph node metastases

BACKGROUND

The differences between primary and metastatic tumor cells might be important for treatment selection and prognostication.

MATERIALS & METHODS

Expression of ER, PR, HER2, CK5/6, EGFR, Ki-67, Ep-CAM, P-cadherin, CD24, CD44, ALDH was assessed immunohistochemically in primary tumor (T) and corresponding synchronous nodal metastases (LNM) in 156 invasive ductal breast cancer patients (T ≥1, N ≥1, M0).

RESULTS

Independent negative prognostic factors for disease-free survival were pN3, ALDH immunopositivity in LNM, nonluminal A subtype in LNM, reduction of Ep-CAM expression in LNM, lack of changes or enhancement of CK5/6 and ALDH expression in LNM.

DISCUSSION

Our results suggest that in some cases expression of markers in lymph node metastases might bring additional prognostic information to that obtained from primary tumor.

Life-threatening metastasis was suppressed by trastuzumab containing regimen in a patient with Her2-negative breast cancer

A 49-year-old female was referred to our hospital with left breast cancer and subsequently underwent mastectomy and axillary dissection. The pathological findings showed invasive breast cancer with lymph node metastasis (2/22), nuclear grade 3, ER (6+) PgR (2+) for the Allred score, and Her2 (2+) in an immunohistochemistry. We determined the subtype of Her2-negative breast cancer according to the fluorescent in situ hybridization results, as follows: Her2/CEP17 ratio 1.1 < 2.0. The patient received the EC regimen followed by docetaxel, and toremifene was subsequently administered. One year after the operation, the CA15-3 level was elevated at 50 ng/ml, and CT revealed liver metastases. Disease progression was not suppressed by paclitaxel containing regimen and eribulin. Then, we subsequently sought to determine whether the metastatic lesion showed the Her2 expression. Although the Her2 expression in the axillary lymph node metastases showed heterogeneous staining, the results were judged as Her2 (1+) according to the ASCO/CAP guidelines. We decided to administer trastuzumab and docetaxel due to the patient's life-threatening status, after which the CA15-3 level decreased and the symptom of fatigue improved. A total of 9 cycles of trastuzumab and docetaxel were administered, followed by maintenance trastuzumab continued to the present time. Physicians should be aware of the statement in the ASCO/CAP guidelines that the clinical decision to ultimately consider Her2-targeted therapy should be individualized according to the patient's status.

Five or more years of adjuvant endocrine therapy in breast cancer: a meta-analysis of published randomised trials

Five years of adjuvant hormonal therapy is the standard of care in early breast cancer (BC) expressing oestrogen receptors (ER+). Prolonged duration of adjuvant endocrine therapy is implemented to prevent recurrence and death; in particular, its carryover effect may prevent very late events. This meta-analysis compares the efficacy of 5 years of hormonal therapy alone with that of additional years of hormonal therapy, in patients with early BC. Randomised trials comparing 5 years versus more than 5 years of hormonal therapy in BC were identified by electronic searches of PubMed, EMBASE, ISI Web of Science and the Cochrane Central Register of Controlled Trials. Meta-analysis was performed using the fixed- or random-effects models. The primary endpoints were overall survival (OS), BC-specific survival (BCSS) and relapse-free survival (RFS) reported as odds ratios (ORs) and 95 % confidence interval (CI). Eight trials, including 29,138 patients, were identified. Overall, in ER+ BCs, extended endocrine therapy beyond 5 years of tamoxifen significantly improved OS (OR, 0.89; 95 % CI 0.80-0.99; P = 0.03), BCSS (OR, 0.78; 95 % CI 0.69-0.9; P = 0.0003) and RFS (OR 0.72; 95 % CI 0.56-0.92; P = 0.01) compared with 5 years of hormonal therapy alone. Loco-regional and distant relapses were reduced by 36 and 13 %, respectively. Compared with 5 years of tamoxifen, additional adjuvant endocrine therapy reduced risk of death and relapse of ER+ BC by ~10 and 30 %, respectively. This strategy should be considered in patients free of disease after 5 years of hormonal therapy.