Cell-cycle inhibition and immune microenvironment in breast cancer treated with ribociclib and letrozole or chemotherapy.

In this study, we performed genomic analyses of cell cycle and tumor microenvironment changes during and after ribociclib and letrozole or chemotherapy in the CORALLEEN trial. 106 women with untreated PAM50-defined Luminal B early breast cancers were randomly assigned to receive neoadjuvant ribociclib and letrozole or standard-of-care chemotherapy. Ki67 immunohistochemistry, tumor-infiltrating lymphocytes quantification, and RNA sequencing were obtained from tissue biopsies pre-treatment, on day 14 of treatment, and tumor specimens from surgical resection. Results showed that at surgery, Ki67 and the PAM50 proliferation scores were lower after ribociclib compared to chemotherapy. However, consistent reactivation of tumor cell proliferation from day 14 to surgery was only observed in the ribociclib arm. In tumors with complete cell cycle arrest (CCCA) at surgery, PAM50 proliferation scores were lower in the ribociclib arm compared to chemotherapy (p < 0.001), whereas the opposite was observed with tumor cellularity (p = 0.002). Gene expression signatures (GES) associated with antigen-presenting cells (APCs) and innate immune system activity showed increased expression post-chemotherapy but decreased expression post-ribociclib. Interferon-associated GES had decreased expression with CCCA and increased expression with non-CCCA. Our findings suggest that while both treatment strategies decreased proliferation, the depth and the patterns over time differed by treatment arm. Immunologically, ribociclib was associated with downregulated GES associated with APCs and the innate immune system in Luminal B tumors, contrary to existing preclinical data. Further studies are needed to understand the effect of CDK4/6 inhibition on the tumor cells and microenvironment, an effect which may vary according to tumor subtypes.

Clinical Impact of New Treatment Strategies for HER2-Positive Metastatic Breast Cancer Patients with Resistance to Classical Anti-HER Therapies.

HER2-positive breast cancer accounts for 15-20% of all breast cancer cases. This subtype is characterized by an aggressive behavior and poor prognosis. Anti-HER2 therapies have considerably improved the natural course of the disease. Despite this, relapse still occurs in around 20% of patients due to primary or acquired treatment resistance, and metastasis remains an incurable disease. This article reviews the main mechanisms underlying resistance to anti-HER2 treatments, focusing on newer HER2-targeted therapies. The progress in anti-HER2 drugs includes the development of novel antibody-drug conjugates with improvements in the conjugation process and novel linkers and payloads. Moreover, trastuzumab deruxtecan has enhanced the efficacy of trastuzumab emtansine, and the new drug trastuzumab duocarmazine is currently undergoing clinical trials to assess its effect. The combination of anti-HER2 agents with other drugs is also being evaluated. The addition of immunotherapy checkpoint inhibitors shows some benefit in a subset of patients, indicating the need for useful biomarkers to properly stratify patients. Besides, CDK4/6 and tyrosine kinase inhibitors are also included in the design of new treatment strategies. Lapitinib, neratinib and tucatinib have been approved for HER2-positive metastasis patients, however clinical trials are currently ongoing to optimize combined strategies, to reduce toxicity, and to better define the useful setting. Clinical research should be strengthened along with the discovery and validation of new biomarkers, as well as a deeper understanding of drug resistance and action mechanisms.

Managing a Long and Winding Road: Estrogen Receptor-Positive Breast Cancer.

We review key topics in the management of estrogen receptor (ER)-positive human epidermal growth factor receptor 2-negative breast cancer. The single biggest challenge in management of this disease is late relapse, and we review new methods for identifying which patients are at risk of late relapse and potential therapeutic approaches in clinical trials. CDK4/6 inhibitors have become a standard treatment option for high-risk patients in both the adjuvant setting and the first-line metastatic setting, and we review data on optimal treatment after progression on CDK4/6 inhibitors. Targeting the estrogen receptor remains the single most effective way of targeting the cancer, and we review the developments in new oral selective ER degraders that are becoming a standard of care in cancers with ESR1 mutations and potential future directions.

miR-146a-5p Promotes Angiogenesis and Confers Trastuzumab Resistance in HER2+ Breast Cancer.

Trastuzumab treatment has significantly improved the prognosis of HER2-positive breast cancer patients. Despite this, resistance to therapy still remains the main clinical challenge. In order to evaluate the implication of microRNAs in the trastuzumab response, we performed a microRNA array in parental and acquired trastuzumab-resistant HER2-positive breast cancer cell lines. Our results identified miR-146a-5p as the main dysregulated microRNA. Interestingly, high miR-146a-5p expression in primary tumor tissue significantly correlated with shorter disease-free survival in HER2-positive breast cancer patients. The gain- and loss-of-function of miR-146a-5p modulated the response to trastuzumab. Furthermore, the overexpression of miR-146a-5p increased migration and angiogenesis, and promoted cell cycle progression by reducing CDKN1A expression. Exosomes from trastuzumab-resistant cells showed a high level of miR-146a-5p expression compared with the parental cells. In addition, the co-culture with resistant cells' exosomes was able to decrease in sensitivity and increase the migration capacities in trastuzumab-sensitive cells, as well as angiogenesis in HUVEC-2 cells. Collectively, these data support the role of miR-146a-5p in resistance to trastuzumab, and demonstrate that it can be transferred by exosomes conferring resistance properties to other cells.

High VEGFR3 Expression Reduces Doxorubicin Efficacy in Triple-Negative Breast Cancer.

Due to the lack of specific targets, cytotoxic chemotherapy still represents the common standard treatment for triple-negative breast patients. Despite the harmful effect of chemotherapy on tumor cells, there is evidence that treatment could modulate the tumor microenvironment in a way favoring the propagation of the tumor. In addition, the lymphangiogenesis process and its factors could be involved in this counter-therapeutic event. In our study, we have evaluated the expression of the main lymphangiogenic receptor VEGFR3 in two triple-negative breast cancer in vitro models, resistant or not to doxorubicin treatment. The expression of the receptor, at mRNA and protein levels, was higher in doxorubicin-resistant cells than in parental cells. In addition, we confirmed the upregulation of VEGFR3 levels after a short treatment with doxorubicin. Furthermore, VEGFR3 silencing reduced cell proliferation and migration capacities in both cell lines. Interestingly, high VEGFR3 expression was significantly positively correlated with worse survival in patients treated with chemotherapy. Furthermore, we have found that patients with high expression of VEGFR3 present shorter relapse-free survival than patients with low levels of the receptor. In conclusion, elevated VEGFR3 levels correlate with poor survival in patients and with reduced doxorubicin treatment efficacy in vitro. Our results suggest that the levels of this receptor could be a potential marker of meager doxorubicin response. Consequently, our results suggest that the combination of chemotherapy and VEGFR3 blockage could be a potentially useful therapeutic strategy for the treatment of triple-negative breast cancer.

Acidosis metabólica neonatal por síndrome de enterocolitis inducido por proteína de alimentos: reporte de caso / Neonatal metabolic acidosis caused by food proteininduced enterocolitis syndrome: a case report

El síndrome de enterocolitis inducido por proteínas de los alimentos (FPIES, por su sigla en inglés) es una reacción alérgica no mediada por inmunoglobulina E (IgE) con síntomas gastrointestinales, como vómitos y diarrea. El diagnóstico se basa en criterios clínicos y en una prueba de provocación para confirmarlo. Es una enfermedad desconocida en las unidades neonatales, debido a la inespecificidad de los síntomas en los recién nacidos. La cifra de metahemoglobina elevada es una opción sencilla de aproximación diagnóstica. Se describe el caso clínico de un recién nacido que ingresa al servicio de urgencias por deshidratación, letargia, vómitos, diarrea y acidosis metabólica grave con elevación de metahemoglobina, con mejora clínica y recuperación total tras el inicio del aporte de fórmula elemental. La sospecha diagnóstica se confirmó tras la prueba de provocación positiva.

Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE mediated allergic reaction with gastrointestinal symptoms, such as vomiting and diarrhea. FPIES diagnosis is based on clinical criteria and on a food challenge test. It is an unknown disease in neonatal units due to its nonspecific symptoms in newborn infants. An elevated methemoglobin level is a simple way to approach diagnosis. Here we describe a clinical case of a newborn admitted to the emergency department because of dehydration, lethargy, vomiting, diarrhea, severe metabolic acidosis, and a high methemoglobin level. Clinical improvement and complete recovery was achieved after initiation of elemental formula. The diagnostic suspicion was confirmed after a positive challenge test.

Neonatal metabolic acidosis caused by food proteininduced enterocolitis syndrome: a case report. / Acidosis metabólica neonatal por síndrome de enterocolitis inducido por proteína de alimentos: reporte de caso.

Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE mediated allergic reaction with gastrointestinal symptoms, such as vomiting and diarrhea. FPIES diagnosis is based on clinical criteria and on a food challenge test. It is an unknown disease in neonatal units due to its nonspecific symptoms in newborn infants. An elevated methemoglobin level is a simple way to approach diagnosis. Here we describe a clinical case of a newborn admitted to the emergency department because of dehydration, lethargy, vomiting, diarrhea, severe metabolic acidosis, and a high methemoglobin level. Clinical improvement and complete recovery was achieved after initiation of elemental formula. The diagnostic suspicion was confirmed after a positive challenge test.

El síndrome de enterocolitis inducido por proteínas de los alimentos (FPIES, por su sigla en inglés) es una reacción alérgica no mediada por inmunoglobulina E (IgE) con síntomas gastrointestinales, como vómitos y diarrea. El diagnóstico se basa en criterios clínicos y en una prueba de provocación para confirmarlo. Es una enfermedad desconocida en las unidades neonatales, debido a la inespecificidad de los síntomas en los recién nacidos. La cifra de metahemoglobina elevada es una opción sencilla de aproximación diagnóstica. Se describe el caso clínico de un recién nacido que ingresa al servicio de urgencias por deshidratación, letargia, vómitos, diarrea y acidosis metabólica grave con elevación de metahemoglobina, con mejora clínica y recuperación total tras el inicio del aporte de fórmula elemental. La sospecha diagnóstica se confirmó tras la prueba de provocación positiva.

Pre-operative ribociclib plus letrozole versus chemotherapy: Health-related quality of life outcomes from the SOLTI CORALLEEN trial.

INTRODUCTION: In the phase II CORALLEEN trial, patients with PAM50 luminal B early breast cancer (EBC) were randomised to neoadjuvant ribociclib plus letrozole (R + L) or chemotherapy based on anthracyclines and taxanes. Results from the primary efficacy analysis showed a similar proportion of patients with response at surgery in both groups. How health-related quality of life (HRQoL) outcomes with R + L compare with chemotherapy in EBC setting is still unknown. Here, we report the results of the HRQoL analysis from the CORALLEEN study. METHODS: A total of 106 women were randomised 1:1 to receive neoadjuvant R + L (n = 52) or chemotherapy (n = 54). Patient-reported outcomes were assessed using two questionnaires: EORTC QLQ-C30 and EORTC QLQ-BR23. Change from baseline in the global health status, functional, and symptom scales was analysed using linear mixed-effect models, and between-treatment differences were estimated along with 95% confidence interval (95% CI). RESULTS: At baseline, the overall questionnaire available rate was 94.3%, and patient-reported outcomes were similar between treatment groups. At the end of the study treatment (24 weeks), patients receiving R + L showed better global health status scores with a between-treatment difference of 17.7 points (95% CI 9.2-26.2; p-value <0.001). The R + L group also presented numerically better outcomes in all functional and symptom scales. The larger between-treatment differences in symptom severity were found in fatigue (-28.9; 95% CI -38.5 to -19.3), appetite loss (-23; 95% CI -34.9 to -11.2) and systematic therapy side-effects (-11.4; 95% CI -18.3 to -4.6). CONCLUSIONS: Neoadjuvant R + L was associated with better HRQoL outcomes compared with chemotherapy in patients with luminal B EBC. REGISTRATION IDENTIFICATION: ClinicalTrials.gov Identifier: NCT03248427.

Immunological Landscape of HER-2 Positive Breast Cancer.

Understanding the biological aspects of immune response in HER2+ breast cancer is crucial to implementing new treatment strategies in these patients. It is well known that anti-HER2 therapy has improved survival in this population, yet a substantial percentage may relapse, creating a need within the scientific community to uncover resistance mechanisms and determine how to overcome them. This systematic review indicates the immunological mechanisms through which trastuzumab and other agents target cancer cells, also outlining the main trials studying immune checkpoint blockade. Finally, we report on anti-HER2 vaccines and include a figure exemplifying their mechanisms of action.

Estado de salud de personas inmigrantes en Cataluña desde una perspectiva de género: proyecto PELFI / Health status among immigrant in Catalonia from a gender perspective: PELFI project

Objetivo: Evaluar el estado de salud de hombres y mujeres inmigrantes extracomunitarios residentes en el Área Metropolitana de Barcelona (Cataluña, España) e identificar determinantes sociales de la salud desde una perspectiva de género. Método: Análisis transversal de una cohorte de familias inmigrantes reclutadas en Badalona y Santa Coloma de Gramenet (cohorte PELFI). En 2015-2016, 167 inmigrantes respondieron al cuestionario epidemiológico basal y al instrumento EuroQol de cinco dimensiones (EQ-5D) que mide el estado de salud. Para identificar determinantes de la salud se construyeron modelos Tobit con el índice EQ-5D. Resultados: Las mujeres declararon una peor salud percibida (p=0,005). Tener una enfermedad diagnosticada se asoció con una peor percepción de la salud en los hombres (p<0,05). El tiempo de estancia y las cargas familiares, en especial la doble jornada de trabajo, empeoraron la salud percibida de las mujeres. En el modelo ajustado por variables demográficas y determinantes sociales, la situación administrativa estable (−0.136; p=0,015) y el apoyo social (0,182; p=0,02) se asociaron con el índice EQ-5D en ambos sexos. Estar ocupado se asoció a mejor salud en los hombres. Conclusiones: Las personas inmigrantes extracomunitarias residentes en el Área Metropolitana de Barcelona son una población vulnerable y presentan desigualdades en salud por sexo. El apoyo social y la ocupación son factores clave de su estado de salud. Las intervenciones para reducir las vulnerabilidades y desigualdades en salud de las personas inmigrantes deberían promover su inclusión y cohesión social, e incorporar la perspectiva de género. (AU)

Objective: The objective of the study is to assess the health status of immigrant men and women from non-EU countries living in the Metropolitan Area of Barcelona (Catalonia, Spain) and to identify the social determinants of health from a gender perspective. Method: Cross-sectional analysis from a cohort of immigrant families recruited in Badalona and Santa Coloma de Gramenet, in Spain (PELFI cohort). In 2015-2016, 167 immigrants answered the baseline epidemiological questionnaire and the 5-level EuroQol instrument (EQ-5D) which measures health status. To identify health determinants, Tobit models were constructed to the EQ-5D index. Results: Women rated poorer self-perceived health (p=0.005). To be diagnosed with and illness was only associated with poor self-perceived health among men (p<0.05). Length of residence, domestic work, and especially double workload deteriorated women's health. After adjusting models by demographics and social determinants, permanent administrative status (−0.136; p=0.015) and social support (0.182; p=0.02) were associated with health status in both sexes. To have a job was associated with better health only in men. Conclusions: Non-EU immigrants living in the Metropolitan Area of Barcelona are a socially vulnerable group of population and present inequalities in health by sex. Social support and occupation are key factors of their health status. Interventions to reduce immigrant vulnerabilities and inequalities in health should promote their social inclusion and cohesion from a gender perspective. (AU)

Targeting HER2-AXL heterodimerization to overcome resistance to HER2 blockade in breast cancer.

Anti-HER2 therapies have markedly improved prognosis of HER2-positive breast cancer. However, different mechanisms play a role in treatment resistance. Here, we identified AXL overexpression as an essential mechanism of trastuzumab resistance. AXL orchestrates epithelial-to-mesenchymal transition and heterodimerizes with HER2, leading to activation of PI3K/AKT and MAPK pathways in a ligand-independent manner. Genetic depletion and pharmacological inhibition of AXL restored trastuzumab response in vitro and in vivo. AXL inhibitor plus trastuzumab achieved complete regression in trastuzumab-resistant patient-derived xenograft models. Moreover, AXL expression in HER2-positive primary tumors was able to predict prognosis. Data from the PAMELA trial showed a change in AXL expression during neoadjuvant dual HER2 blockade, supporting its role in resistance. Therefore, our study highlights the importance of targeting AXL in combination with anti-HER2 drugs across HER2-amplified breast cancer patients with high AXL expression. Furthermore, it unveils the potential value of AXL as a druggable prognostic biomarker in HER2-positive breast cancer.

Development of a Novel NGS Methodology for Ultrasensitive Circulating Tumor DNA Detection as a Tool for Early-Stage Breast Cancer Diagnosis.

Breast cancer (BC) is the most prevalent cancer in women. While usually detected when localized, invasive procedures are still required for diagnosis. Herein, we developed a novel ultrasensitive pipeline to detect circulating tumor DNA (ctDNA) in a series of 75 plasma samples from localized BC patients prior to any medical intervention. We first performed a tumor-informed analysis to correlate the mutations found in tumor tissue and plasma. Disregarding the tumor data next, we developed an approach to detect tumor mutations in plasma. We observed a mutation concordance between the tumor and plasma of 29.50% with a sensitivity down to 0.03% in mutant variant allele frequency (VAF). We detected mutations in 33.78% of the samples, identifying eight patients with plasma-only mutations. Altogether, we determined a specificity of 86.36% and a positive predictive value of 88.46% for BC detection. We demonstrated an association between higher ctDNA median VAF and higher tumor grade, multiple plasma mutations with a likelihood of relapse and more frequent TP53 plasma mutations in hormone receptor-negative tumors. Overall, we have developed a unique ultra-sensitive sequencing workflow with a technology not previously employed in early BC, paving the way for its application in BC screening.

[Health status among immigrant in Catalonia from a gender perspective: PELFI project]. / Estado de salud de personas inmigrantes en Cataluña desde una perspectiva de género: Proyecto PELFI.

OBJECTIVE: The objective of the study is to assess the health status of immigrant men and women from non-EU countries living in the Metropolitan Area of Barcelona (Catalonia, Spain) and to identify the social determinants of health from a gender perspective. METHOD: Cross-sectional analysis from a cohort of immigrant families recruited in Badalona and Santa Coloma de Gramenet, in Spain (PELFI cohort). In 2015-2016, 167 immigrants answered the baseline epidemiological questionnaire and the 5-level EuroQol instrument (EQ-5D) which measures health status. To identify health determinants, Tobit models were constructed to the EQ-5D index. RESULTS: Women rated poorer self-perceived health (p=0.005). To be diagnosed with and illness was only associated with poor self-perceived health among men (p<0.05). Length of residence, domestic work, and especially double workload deteriorated women's health. After adjusting models by demographics and social determinants, permanent administrative status (-0.136; p=0.015) and social support (0.182; p=0.02) were associated with health status in both sexes. To have a job was associated with better health only in men. CONCLUSIONS: Non-EU immigrants living in the Metropolitan Area of Barcelona are a socially vulnerable group of population and present inequalities in health by sex. Social support and occupation are key factors of their health status. Interventions to reduce immigrant vulnerabilities and inequalities in health should promote their social inclusion and cohesion from a gender perspective.

Molecular profiling of advanced solid tumours. The impact of experimental molecular-matched therapies on cancer patient outcomes in early-phase trials: the MAST study.

INTRODUCTION: Molecular-matched therapies have revolutionized cancer treatment. We evaluated the improvement in clinical outcomes of applying an in-house customized Next Generation Sequencing panel in a single institution. METHODS: Patients with advanced solid tumors were molecularly selected to receive a molecular-matched treatment into early phase clinical trials versus best investigators choice, according to the evaluation of a multidisciplinary molecular tumor board. The primary endpoint was progression-free survival (PFS) assessed by the ratio of patients presenting 1.3-fold longer PFS on matched therapy (PFS2) than with prior therapy (PFS1). RESULTS: Of a total of 231 molecularly screened patients, 87 were eligible for analysis. Patients who received matched therapy had a higher median PFS2 (6.47 months; 95% CI, 2.24-14.43) compared to those who received standard therapy (2.76 months; 95% CI, 2.14-3.91, Log-rank p = 0.022). The proportion of patients with a PFS2/PFS1 ratio over 1.3 was significantly higher in the experimental arm (0.33 vs 0.08; p = 0.008). DISCUSSION: We demonstrate the pivotal role of the institutional molecular tumor board in evaluating the results of a customized NGS panel. This process optimizes the selection of available therapies, improving disease control. Prospective randomized trials are needed to confirm this approach and open the door to expanded drug access.

Fertility and breast cancer: A literature review of counseling, preservation options and outcomes.

Fertility preservation is an important issue in breast cancer patients undergoing oncological treatment. Fertility counseling is a crucial need given the physical and psychological stress experienced by patients. Cryopreservation of mature oocytes is currently the standard fertility-preserving procedure. Other options such as ovarian tissue preservation or gonadal protection during chemotherapy are still experimental, but have proven effectiveness. Prompt referral to a fertility unit is highly recommended in order to ensure quality of care. In this article, we focus on the different strategies to preserve fertility in breast cancer patients, assessing also the safety of pregnancy and breastfeeding after cancer. A systemic literature review was performed for research articles published in English in PubMed, or as abstracts from the European Society for Medical Oncology (ESMO), San Antonio Breast Cancer Symposium (SABCS) and American Society of Clinical Oncology (ASCO) annual meetings, using the search terms "breast cancer" and "fertility".

Oral Selective Estrogen Receptor Degraders (SERDs) as a Novel Breast Cancer Therapy: Present and Future from a Clinical Perspective.

Estrogen receptor-positive (ER+) is the most common subtype of breast cancer. Endocrine therapy is the fundamental treatment against this entity, by directly or indirectly modifying estrogen production. Recent advances in novel compounds, such as cyclin-dependent kinase 4/6 inhibitors (CDK4/6i), or phosphoinositide 3-kinase (PI3K) inhibitors have improved progression-free survival and overall survival in these patients. However, some patients still develop endocrine resistance after or during endocrine treatment. Different underlying mechanisms have been identified as responsible for endocrine treatment resistance, where ESR1 gene mutations are one of the most studied, outstanding from others such as somatic alterations, microenvironment involvement and epigenetic changes. In this scenario, selective estrogen receptor degraders/downregulators (SERD) are one of the weapons currently in research and development against aromatase inhibitor- or tamoxifen-resistance. The first SERD to be developed and approved for ER+ breast cancer was fulvestrant, demonstrating also interesting activity in ESR1 mutated patients in the second line treatment setting. Recent investigational advances have allowed the development of new oral bioavailable SERDs. This review describes the evolution and ongoing studies in SERDs and new molecules against ER, with the hope that these novel drugs may improve our patients' future landscape.

Identification of a Two-MicroRNA Signature in Plasma as a Novel Biomarker for Very Early Diagnosis of Breast Cancer.

The early diagnosis of breast cancer is essential to improve patients' survival rate. In this context, microRNAs have been described as potential diagnostic biomarkers for breast cancer. Particularly, circulating microRNAs have a strong value as non-invasive biomarkers. Herein, we assessed the potential of a microRNA signature based on miR-30b-5p and miR-99a-5p levels in plasma as a diagnostic biomarker for breast cancer. This two-microRNA signature was constructed by Principal Component Analysis and its prognostic value was assessed in a discovery cohort and blindly validated in a second cohort from an independent institution. ROC curve analysis and biomarker performance parameter evaluation demonstrated that our proposed signature presents a high value as a non-invasive biomarker for very early detection of breast cancer. In addition, pathway enrichment analysis identified three of the well-known pathways involved in cancer as targets of the two microRNAs.

Palbociclib combined with endocrine therapy in heavily pretreated HR+/HER2- advanced breast cancer patients: Results from the compassionate use program in Spain (PALBOCOMP).

BACKGROUND: This study evaluated efficacy and safety of palbociclib, a CDK4/6 inhibitor, in heavily-pretreated hormone receptor-positive and human epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast cancer (mBC) patients during the compassionate use program in Spain from February 2015 to November 2017. PATIENTS AND METHODS: Patient data were collected retrospectively from 35 hospitals in Spain. Patients with HR+/HER2- mBC who had progressed on ≥4 treatments for advanced disease were eligible. RESULTS: A total of 219 patients received palbociclib in combination with aromatase inhibitors (110; 50.2%), fulvestrant (87; 39.7%), tamoxifen (8; 3.6%) or as single agent (10; 4.6%). Mean age of the patients was 58 years; 31 patients (16.1%) were premenopausal and 162 (83.9%) were postmenopausal at the beginning of treatment with palbociclib. Patients had received a median of 3 previous lines of endocrine therapy (ET) for advanced disease. Real-world tumor response (rwTR) and clinical benefit rate were 5.9% (n = 13) and 46.2% (n = 101), respectively. The median real world progression-free survival (rwPFS) was 6.0 months (95% CI 5.7-7.0) and the median overall survival was 19.0 months (95% CI 16.4-21.7). Subgroup analysis revealed a significant difference in median rwPFS in patients treated with palbociclib plus fulvestrant depending on the duration of prior treatment with fulvestrant monotherapy (>6 versus ≤6 months; HR 1.93, 95% CI 1.37-2.73, p < 0.001). The most frequently reported toxicities were neutropenia, asthenia, thrombopenia and anemia. CONCLUSIONS: Palbociclib can be an effective and safe treatment option in patients with heavily pretreated endocrine-sensitive mBC, especially in those with longer PFS to previous ET.

Circulating miR-99a-5p Expression in Plasma: A Potential Biomarker for Early Diagnosis of Breast Cancer.

MicroRNAs have emerged as new diagnostic and therapeutic biomarkers for breast cancer. Herein, we analysed miR-99a-5p expression levels in primary tumours and plasma of breast cancer patients to evaluate its usefulness as a minimally invasive diagnostic biomarker. MiR-99a-5p expression levels were determined by quantitative real-time PCR in three independent cohorts of patients: (I) Discovery cohort: breast cancer tissues (n = 103) and healthy breast tissues (n = 26); (II) Testing cohort: plasma samples from 105 patients and 98 healthy donors; (III) Validation cohort: plasma samples from 89 patients and 85 healthy donors. Our results demonstrated that miR-99a-5p was significantly downregulated in breast cancer tissues compared to healthy breast tissues. Conversely, miR-99a-5p levels were significantly higher in breast cancer patients than in healthy controls in plasma samples from both testing and validation cohorts, and ROC curve analysis revealed that miR-99a-5p has good diagnostic potential even to detect early breast cancer. In conclusion, miR-99a-5p's deregulated expression distinguished healthy patients from breast cancer patients in two different types of samples (tissues and plasma). Interestingly, expression levels in plasma were significantly lower in healthy controls than in early-stage breast cancer patients. Our findings suggest circulating miR-99a-5p as a novel promising non-invasive biomarker for breast cancer detection.

MicroRNA-33b Suppresses Epithelial-Mesenchymal Transition Repressing the MYC-EZH2 Pathway in HER2+ Breast Carcinoma.

Downregulation of miR-33b has been documented in many types of cancers and is being involved in proliferation, migration, and epithelial-mesenchymal transition (EMT). Furthermore, the enhancer of zeste homolog 2-gene (EZH2) is a master regulator of controlling the stem cell differentiation and the cell proliferation processes. We aim to evaluate the implication of miR-33b in the EMT pathway in HER2+ breast cancer (BC) and to analyze the role of EZH2 in this process as well as the interaction between them. miR-33b is downregulated in HER2+ BC cells vs healthy controls, where EZH2 has an opposite expression in vitro and in patients' samples. The upregulation of miR-33b suppressed proliferation, induced apoptosis, reduced invasion, migration and regulated EMT by an increase of E-cadherin and a decrease of ß-catenin and vimentin. The silencing of EZH2 mimicked the impact of miR-33b overexpression. Furthermore, the inhibition of miR-33b induces cell proliferation, invasion, migration, EMT, and EZH2 expression in non-tumorigenic cells. Importantly, the Kaplan-Meier analysis showed a significant association between high miR-33b expression and better overall survival. These results suggest miR-33b as a suppressive miRNA that could inhibit tumor metastasis and invasion in HER2+ BC partly by impeding EMT through the repression of the MYC-EZH2 loop.