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[Purpose]: To characterize expression of neuregulin-1 (NRG1), an HER3 ligand, in HER2-positive breast cancer and its relation with the efficacy of trastuzumab with or without pertuzumab., [Experimental Design]: Characterization of NRG1 expression in tumor cell lines, in tumor specimens, and in cancer-associated fibroblasts (CAFs). Patient-derived CAFs were used to investigate NRG1 impact on the activity of trastuzumab with or without pertuzumab in HER2-positive breast cancer cells. The relationship between NRG1 expression and pathologic response to anti-HER2–based neoadjuvant therapy was assessed in a retrospective patient cohort and in the NeoSphere trial., [Results]: NRG1 was expressed in HER2-positive breast cancer–derived fibroblasts at significantly higher levels than in cancer cells. NRG1 and the conditioned media (CM) from CAFs phosphorylated HER3 and AKT in cancer cells and mediated trastuzumab resistance. Stable genetic depletion of NRG1 from CAFs overcame trastuzumab resistance. Pertuzumab effectively suppressed trastuzumab resistance mediated by either NRG1 or CAF's CM. NRG1 engaged an epithelial-to-mesenchymal transition that was prevented by trastuzumab and pertuzumab. In clinical samples, stromal and/or tumor cell expression of NRG1 determined by immunohistochemistry was uncommon (13.2%) yet significantly linked with residual disease following trastuzumab-based neoadjuvant therapy. In the NeoSphere trial, the magnitude of the difference of pathologic complete response rates favoring the pertuzumab arm was higher in the NRG1-high group., [Conclusions]: CAF-derived NRG1 mediates trastuzumab resistance through HER3/AKT, which might be reverted by pertuzumab. In patients with HER2-positive breast cancer, high expression of NRG1 was associated to poor response to trastuzumab, but not in combination with pertuzumab., This work is supported by ISCIII (CIBERONC CB16/12/00481, CB16/12/00241, PI18/00382, PI18/00006, PI18/01219 and by Generalitat de Catalunya (2017 SGR 507). S. Menendez is supported by Department de Salut, Generalitat de Catalunya (PERIS SLT006/17/00040). MARBiobanc is supported by ISCiii/FEDER (PT17/0015/0011) and by “Xarxa de Bancs de tumors” sponsored by Pla Director d’ Oncologia de Catalunya (XBTC) and Fundacion Jimenez Díaz Biobanks Platform by PT13/0010/0012 grant. Ministry of Economy and Competitiveness of Spain (BFU2015-71371-R) and the CRIS Cancer Foundation provides support to A. Pandiella. Work carried out in our laboratories receive support from the European Community through the Regional Development Funding Program (FEDER). J.C. Montero is funded by the ISCIII through a Miguel Servet program (CPII17/00015) and receives research support from the same institution (PI18/00796). J. Albanell is supported by Breast Cancer Research Foundation (BCRF20-08), Instituto de Salud Carlos III Project Reference number AC15/00062 and the EC under the framework of the ERA-NET TRANSCAN-2 initiative co-financed by FEDER, Instituto de Salud Carlos III (CB16/12/00449 and PI19/01181), and Asociacion Espanola Contra el Cáncer (AECC).

[EN] We report herein an evaluation of the effect of several mesoporous silica nanoparticles (MSNs) on the cellular uptake and in vitro cytotoxicity in human cells. Bare MSNs and MSNs functionalized with polyethylene glycol or hyaluronic acid are employed to evaluate uptake efficiency and mechanisms of endocytosis in cancer (MDA-MB-231) and non-cancer (MCF10A) cells. Moreover, changes in viability, cell cycle, oxidative stress, and mitochondrial membrane potential are evaluated. Our results confirm that MSNs are internalized efficiently by human cells and that uptake mechanisms differ for cell types and particles. We also confirm that MSNs are biocompatible materials that do not induce ROS/RNS production, nor changes on mitochondrial membrane potential or cell cycle., The authors want to thank the Spanish Government RTI2018-100910-B-C41 (MCUI/AEI/FEDER, UE) and PI18/01219 (ISCIII), the Generalitat Valenciana (PROMETEO/2018/024 and ACIF/2016/030), and CIBER-BBN (CB07/01/2012) and CIBER-ONC (CB16/12/00481) for support.

Background Recently, microRNAs have been demonstrated to be potential non-invasive biomarkers for diagnosis, prognosis assessment or prediction of response to treatment in cancer. In this study, we evaluate the potential of miR-30b-5p as a biomarker for early diagnosis of breast cancer (BC) in tissue and plasma. Methods Expression of miR-30b-5p was determined in a series of 112 BC and 40 normal breast tissues. Circulating miR-30b-5p levels in plasma samples were determined in a discovery cohort of 38 BC patients and 40 healthy donors and in a validation cohort of 83 BC patients and 83 healthy volunteers. miR-30b-5p expression was measured by quantitative real-time PCR and receiver operating characteristics curve analysis was carried out. Results The miR-30b-5p expression was significantly lower in BC tissue than in healthy breast samples. In contrast, circulating miR-30b-5p levels were significantly higher in BC patients compared with healthy donors. Furthermore, circulating miR-30b-5p levels were significantly higher in patients with positive axillary lymph node and de novo metastatic patients. Receiver operating characteristics curve analysis demonstrated a good diagnostic potential of miR-30b-5p to detect BC even at an early stage of the disease. Conclusion Thus, we highlight the potential of miR-30b-5p as a non-invasive, fast, reproducible and cost-effective diagnostic biomarker of BC., Highlights Our results show the following: • Low miR-30b-5p expression was detected in breast tumor tissue compared with healthy breast tissue. • High circulating miR-30b-5p levels in plasma were associated to breast cancer. • miR-30b-5p levels in plasma identify breast cancer of all subtypes and stages of the disease. • Circulating miR-30b-5p levels relate with patients' tumor burden. • Circulating miR-30b-5p is a potential non-invasive and cost-effective diagnostic BC biomarker.

Background In recent years, the identification of genetic and phenotypic biomarkers of cancer for prevention, early diagnosis and patient stratification has been a main objective of research in the field. Different multivariable models that use biomarkers have been proposed for the evaluation of individual risk of developing breast cancer. Methods This is a case control study based on a population-based cohort. We describe and evaluate a multivariable model that incorporates 92 Single-nucleotide polymorphisms (SNPs) (Supplementary Table S1) and five different phenotypic variables and which was employed in a Spanish population of 642 healthy women and 455 breast cancer patients. Results Our model allowed us to stratify two groups: high and low risk of developing breast cancer. The 9th decile included 1% of controls vs 9% of cases, with an odds ratio (OR) of 12.9 and a p-value of 3.43E-07. The first decile presented an inverse proportion: 1% of cases and 9% of controls, with an OR of 0.097 and a p-value of 1.86E-08. Conclusions These results indicate the capacity of our multivariable model to stratify women according to their risk of developing breast cancer. The major limitation of our analysis is the small cohort size. However, despite the limitations, the results of our analysis provide proof of concept in a poorly studied population, and opens up the possibility of using this method in the routine screening of the Spanish population.

Kaposi’s sarcoma-associated herpesvirus (KSHV) vGPCR is a constitutively active G protein-coupled receptor that subverts proliferative and inflammatory signaling pathways to induce cell transformation in Kaposi’s sarcoma. Cyclooxygenase-2 (COX-2) is an inflammatory mediator that plays a key regulatory role in the activation of tumor angiogenesis. Using two different transformed mouse models and tumorigenic full KSHV genome-bearing cells, including KSHV-Bac16 based mutant system with a vGPCR deletion, we demostrate that vGPCR upregulates COX-2 expression and activity, signaling through selective MAPK cascades. We show that vGPCR expression triggers signaling pathways that upregulate COX-2 levels due to a dual effect upon both its gene promoter region and, in mature mRNA, the 3’UTR region that control mRNA stability. Both events are mediated by signaling through ERK1/2 MAPK pathway. Inhibition of COX-2 in vGPCR-transformed cells impairs vGPCR-driven angiogenesis and treatment with the COX-2-selective inhibitory drug Celecoxib produces a significant decrease in tumor growth, pointing to COX-2 activity as critical for vGPCR oncogenicity in vivo and indicating that COX-2-mediated angiogenesis could play a role in KS tumorigenesis. These results, along with the overexpression of COX-2 in KS lesions, define COX-2 as a potential target for the prevention and treatment of KSHV-oncogenesis., Author summary Kaposi sarcoma (KS) is the most frequent AIDS-related cancer (AIDS-KS). The tumors originate in cells infected with a cancer-causing virus (KSHV). A gene encoded by the virus expresses a protein with oncogenic potential in the infected cells (vGPCR), which has the ability to promote cell transformation and angiogenesis driving KS tumorigenesis. Therefore, the identification of oncogenic intracellular signalling mechanisms triggered by vGPCR could be of therapeutic interest. Cyclooxygenase-2 (COX-2) is an inflammatory molecule involved in tumor angiogenesis that can be targeted by several FDA-approved non-steroidal anti-inflammatory drugs and specific inhibitors. Here, we demonstrate that vGPCR upregulates COX-2 activity and expression through upregulation of transcription and mRNA stability via an ERK1/2 dependent pathway. We also show that COX-2 activity is critical for vGPCR angiogenesis and oncogenesis using KSHV infection and mouse models. Consistent with a role in KS pathogenesis, we found that vGPCR upregulates COX-2 activity in endothelial cells, that it is essential for VEGF upregulation via vGPCR, and that it is expressed in KSHV infected cells of AIDS-KS lesions. These facts point to COX-2 as one of the molecular components of the vGPCR angiogenic switch in Kaposi Sarcoma and a potential target for chemoprevention and therapy.

Angiogenesis process contributes to the pathogenesis of B-cell chronic lymphocytic leukemia (B-CLL) being the levels of VEGFA and bFGF higher in patients than in healthy controls. Our aim was to evaluate the implication of angiogenesis factors genetic variants in the predisposition to B-CLL and their association with clinical factors and survival. We performed a population-based case-control study in 224 Spanish B-CLL patients and 476 healthy randomly selected controls to evaluate susceptibility to developing B-CLL. Six polymorphisms were evaluated: rs1109324, rs1547651, rs3025039 (+936 C>T), rs833052 of the VEGFA gene, rs1449683 (c.233C>T) of the bFGF gene and (−710 C>T) of the VEGFR1 gene. The association between clinical parameters and patient outcome was analyzed. Carriers of the CT/TT variants of rs3025039 showed a significant protective effect against developing B-CLL. The CT/TT variants of rs1449683 show a tendency towards the development of the disease and the same variants associated significantly with higher genetic risk and with reduced disease free survival. Moreover, the association persisted in the early-stage disease subgroup. Our study provides evidence of the protective effect of the T/- rs3025039 VEGFA variant against B-CLL development and the association of CT/TT variants of the rs1449683 bFGF gene with genetic risk and an adverse survival.

Together with its reported ability to modulate AKT phosphorylation (p-AKT) status in several tumor types, the oncoprotein CIP2A has been described to induce breast cancer progression and drug resistance. However, the clinical and therapeutic relevance of the CIP2A/AKT interplay in breast cancer remains to be fully clarified. Here, we found high p-AKT levels in 80 out of 220 cases (36.4%), which were associated with negative estrogen receptor expression (p = 0.049) and CIP2A overexpression (p < 0.001). Interestingly, p-AKT determined substantially shorter overall (p = 0.002) and progression-free survival (p = 0.003), and multivariate analyses showed its CIP2A-independent prognostic value. Moreover, its clinical relevance was further confirmed in the triple negative and HER2-positive subgroups after stratifying our series by molecular subtype. Functionally, we confirmed in vitro the role of CIP2A as a regulator of p-AKT levels in breast cancer cell lines, and the importance of the CIP2A/AKT axis was also validated in vivo. Finally, p-AKT also showed a higher predictive value of response to doxorubicin than CIP2A in ex vivo analyses. In conclusion, our findings suggest that CIP2A overexpression is a key contributing event to AKT phosphorylation and highlights the CIP2A/AKT axis as a promising therapeutic target in breast cancer. However, our observations highlight the existence of alternative mechanisms that regulate AKT signaling in a subgroup of breast tumors without altered CIP2A expression that determines its independent value as a marker of poor outcome in this disease.

Background: HER2+ breast cancer (BC) is a heterogeneous disease. Despite the novel targeted therapies against HER2, 20% of patients relapse. In this context, the identification of prognostic and predictor biomarkers is needed.MicroRNAs are involved in BC development and prognosis. We aim at assessing the prognostic significance of two micro-RNAs (named as A and B) in HER2+ BC tissue, to propose signature to predict relapse in this setting of patients.Methods: This study was conducted in a cohort of 46 non-consecutive HER2+ BC patients diagnosed at Hospital Clínico València-INCLIVA. All BC patients received standard treatment for localized disease. RNA was isolated from formalin-fixed paraffin-embedded primary tumor and retro-transcribed to cDNA. MicroRNA expression levels were measured by real-time qPCR and results were normalized according to the expression of housekeeping mir-16 miRNA.Non-parametric Mann-Whitney U test was used to ascertain the statistical significance of differences in miRNA expression levels between disease-free and relapse. Receiver operator characteristics (ROC) curves were constructed and AUC, accuracy, specificity and sensitivity, were calculated as a biomarker performance parameter. The best cutoff value was established based on the highest value obtained in ROC curve analysis according to the maximization of the sum of sensitivity and specificity. Kaplan-Meier curves were plotted for disease-free survival (DFS) based on the best cutoff value. As both microRNA showed high correlation (r=0.85), a genetic signature was developed using Principal Component Analysis (PCA) and extracting the first component. MicroRNA targeted genes were downloaded from miRTarBase (release 7.0). Cytoscape (v3.8.0) and ClueGo (v2.5.6) and were used to perform functional enrichment analysis with the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database. To select significant terms/pathways, p-values were adjusted by the Benjamni-Hochberg method (p Citation Format: Anna Adam-Artigues, Juan Antonio Carbonell-Asíns, Sheila Zúñiga-Trejos, Santiago Moragón, Maria Teresa Martínez, Cristina Hernando, Eduardo Tormo, Octavio Burgués, Ana Lluch, Begoña Bermejo, Pilar Eroles, Juan Miguel Cejalvo. Identification of a novel two-microRNA signature for recurrence prediction in HER2 positive breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS19-20.

Preclinical evidence has shown increased expression of mu opioid receptor 1 (MOR-1) in colorectal cancer although its association with disease-free and overall survival (DFS and OS) has not been investigated. We hypothesized that MOR-1 was overexpressed in tumor samples compared to normal tissue and this was associated with decreased DFS and OS. We carried out a retrospective study assessing the association of MOR-1 tumor expression with long-term outcomes by immunohistochemistry in normal and tumor samples from 174 colorectal cancer patients. The primary endpoint was five years of DFS. Secondary endpoints were five years of OS, the difference in MOR-1 expression between normal and tumor tissue and the occurrence of postoperative complications. Multivariable Cox regression showed no significant association between MOR-1 expression and DFS (HR 0.791, 95% CI 0.603&ndash, 1.039, p = 0.092). MOR-1 expression was higher in tumor tissue compared to non-tumor tissue. No associations were found between MOR-1 expression and OS or postoperative complications. These findings suggest that although MOR-1 is over-expressed in colorectal cancer samples there is no association to increased risk of recurrence or mortality. Future studies are warranted to elucidate the role of cancer stage, genetic polymorphism, and quantitative assessment of MOR-1 over-expression on long-term outcomes in colorectal cancer.

Trastuzumab is the first-line targeted therapeutic drug for HER2-positive breast cancer, leading to improved overall survival. However, acquired resistance inevitably occurs. We aimed to identify, quantify, and assess the mechanisms of acquired resistance to trastuzumab. We established an acquired trastuzumab-resistant model in vitro from BT-474, a trastuzumab-sensitive, HER2-amplified breast-cancer cell line. A multi-omic strategy was implemented to obtain gene, proteome, and phosphoproteome signatures associated with acquired resistance to trastuzumab in HER2-positive breast cancer, followed by validation in human clinical samples. YAP1 dephosphorylation and TEAD2 overexpression were detected as significant alterations in the Hippo pathway in trastuzumab-resistant breast cancer. Because of the emerging role of these proteins as mediators of normal growth and tumorigenesis, we assessed the exogenous modulation of their activity, either by in vitro gene silencing or by pharmacological inhibition of the YAP1/TEAD complexes, both in vitro and in vivo. Moreover, we identified increased signaling through the Hippo pathway in human samples after progression following trastuzumab treatment. Finally, YAP1/TAZ nuclear accumulation in malignant cells in HER2 breast tumor was significantly associated with worse progression-free and overall survival in metastatic HER2-positive breast-cancer patients. Our results suggest the involvement of Hippo signaling in acquired trastuzumab resistance in breast cancer. Additionally, we provide novel evidence for a potential breast-cancer treatment strategy based on dual targeting of HER2 and Hippo pathway effectors, which may improve the antitumor activity of trastuzumab and help overcome resistance., The present work was supported by grants from the Spanish Ministry of Economy and Competitiveness (MINECO) with European Regional Development Fund (ERDF) funding through the Institute of Health Carlos III (AES Program, grants PI15/00934, PI18/00382 and PI18/00006; CIBERONC, Biomedical Research Networking Centre for Cancer; Biobanks Platform, PT13/0010/0012; ProteoRed, PRB2-ISCIII, PT13/0001); and the Community of Madrid (S2010/BMD-2344). P.G.-A. was supported by a Fundación Conchita Rábago de Jiménez Díaz grant. P.M. was supported by the ISCIII Miguel Servet Program (CP16/00116).

Background: Breast cancer in very young women (BCVY) defined as &lt, 35 years old, presents with different molecular biology than in older patients. High HDAC5 expression has been associated with poor prognosis in breast cancer (BC) tissue. We aimed to analyze HDAC5 expression in BCVY and older patients and their correlation with clinical features, also studying the potential of HDAC5 inhibition in BC cell lines. Methods: HDAC5 expression in 60 BCVY and 47 older cases were analyzed by qRT-PCR and correlated with clinical data. The effect of the HDAC5 inhibitor, LMK-235, was analyzed in BC cell lines from older and young patients. We performed time and dose dependence viability, migration, proliferation, and apoptosis assays. Results: Our results correlate higher HDAC5 expression with worse prognosis in BCVY. However, we observed no differences between HDAC5 expression and pathological features. Our results showed greatly reduced progression in BCVY cell lines and also in all triple negative subtypes when cell lines were treated with LMK-235. Conclusions: In BCVY, we found higher expression of HDAC5. Overexpression of HDAC5 in BCVY correlates with lower survival rates. LMK-235 could be a potential treatment in BCVY.

HER2-positive breast cancer is currently managed with chemotherapy in combination with specific anti-HER2 therapies, including trastuzumab. However, a high percentage of patients with HER2-positive tumors do not respond to trastuzumab (primary resistance) or either recur (acquired resistance), mostly due to molecular alterations in the tumor that are either unknown or undetermined in clinical practice. Those alterations may cause the tumor to be refractory to treatment with trastuzumab, promoting tumor proliferation and metastasis. Using continued exposure of a HER2-positive cell line to trastuzumab, we generated a model of acquired resistance characterized by increased expression of several cytokines. Differential gene expression analysis indicated an overexpression of 15 genes, including five different chemokines, and highlighting CCL5/RANTES as the most overexpressed one. Functional studies, either by in vitro gene silencing or by in vitro and in vivo pharmacologic inhibition of the CCL5/CCR5 interaction with maraviroc, confirmed that CCL5 overexpression was implicated in acquired resistance to trastuzumab, which was mediated by ERK activation. In patient samples, increased CCL5 expression significantly correlated with lower rates of complete response after neoadjuvant therapy, confirmed by detection of high serum CCL5 levels by ELISA. Overexpression of CCL5 correlated with ERK phosphorylation in tumor cells and was statistically associated with worse disease-free survival and overall cancer survival in patients with early HER2-positive breast cancer.

The mechanisms of chemotherapy resistance in triple negative breast cancer remain unclear, and so, new molecules which might mediate this resistance could optimize treatment response. Here we analyzed the involvement of the miRNA-449 family in the response to doxorubicin. The cell viability, cell-cycle phases, and the expression of in silico target genes and proteins of sensitive/resistant triple negative breast cancer cell lines were evaluated in response to doxorubicin treatment and after gain/loss of miRNAs-449 function achieved by transient transfection. Triple negative breast cancer patients were selected for ex vivo experiments and to evaluate gene and miRNAs expression changes after treatment, as well as survival analysis by Kaplan-Meier. Doxorubicin treatment upregulated miRNAs-449 and DNA-damage responder factors E2F1 and E2F3 in triple negative breast cancer sensitive breast cancer cells, while expression remained unaltered in resistant ones. In vitro overexpression of miRNAs-449 sensitized cells to the treatment and significantly reduced the resistance to doxorubicin. These changes showed also a strong effect on cell cycle regulation. Finally, elevated levels of miRNA-449a associated significantly with better survival in chemotherapy-treated triple negative breast cancer patients. These results reveal for the first time the involvement of the miRNA-449 family in doxorubicin resistance and their predictive and prognostic value in triple negative breast cancer patients.

Introduction HER2+ correlates with aggressive phenotype and poor prognosis. The use of several antiHER2 drugs has dramatically improved prognosis and survival of HER2+ breast cancer (BC) patients. However, ≈20% of these patients will present resistance to antiHER2 therapies and relapse. The purpose of this study is to explore the role of AXL in antiHER2 treatment resistance and its potential as a druggable biomarker in HER2+ BC. Methods We generated 2 trastuzumab (T) resistant models from a HER2+ BC patient. The first one was a PDX derived resistant cell line established by chronic treatment for 6 months with T in vitro (TR1 and TR2). The second resistant model (TR4) was established by chronic treatment with T for 4 months and two serial passages in mice. The prognostic value of AXL was evaluated in primary tumor cohort of HER2+ BC patients treated by standard guidelines (n=51). AXL was also explored in a cohort from PAMELA trial, a neoadjuvant phase II study. Patients were given lapatinib and T for 18 weeks (Luminal-HER2+ patients were additionally given hormonotherapy). Tumor samples were collected at baseline, day 14 and surgery (n= 96). Results PDX resistant cell lines (TR1 and TR2) and resistant tumors (TR4) exhibit upregulation of AXL in comparison to the parental cells (PDX118). In vitro, the combination of an AXL inhibitor (TP-0903) + T resensitized resistant cells to T. In 3D organoids models from TR4, the combination decreased cell number in organoids more than both single agents. In TR4 in vivo model, TP-0903 + T completely abrogate tumor growth for more than 2 months.To validate our preclinical findings, we analyzed the level of AXL in our retrospectively cohort of patients. AXL level was significantly upregulated in patients who relapsed (p Conclusion AXL level was correlated with poor outcome of HER2+ BC patients. On our preclinical models, we showed that combination of TP-0903 and T abrogate tumor growth in acquired resistant models to T in PDXs. We postulate AXL as a promising new therapeutic strategy to overcome resistance to antiHER2 therapies Citation Format: Anna Adam-Artigues, Raimundo Cervera, Enrique Javier Arenas, Fara Brasó-Maristany, Alex Martinez-Sabadell, Eduardo Tormo, Cristina Hernando, Maria Teresa Martinez, Soraya Simon, Jesús Poveda, Octavio Burgués, Ana Rovira, Federico Rojo, Joan Albanell, Begoña Bermejo, Ana Lluch, Pilar Eroles, Aleix Prat, Joaquin Arribas, Juan Miguel Cejalvo. AXL is a potential druggable target in trastuzumab resistance in HER2+ breast cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1075.

Simple Summary Breast cancer diagnosis at the initial stage of the disease considerably improves prognosis and survival rates. This retrospective study aimed to develop and validate a plasma microRNA signature as a non-invasive biomarker for early-stage breast cancer diagnosis. We confirmed in a testing cohort of 54 BC patients and 89 healthy volunteers the value of a signature based on miR-30b and miR-99a levels in plasma samples for stage I breast cancer detection. Furthermore, our results were blindly validated in a second cohort of 74 breast cancer and 74 healthy samples. The proposed microRNA signature presented high value as a fast, cost-effective, and non-invasive biomarker for early-stage breast cancer detection, which will lead to a better prognosis for breast cancer patients. Abstract 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.

1083 Background: Triple-negative breast cancer (TNBC) is an aggressive breast cancer (BC) subtype comprising approximately 15% of BC. Conventional cytotoxic chemotherapies continue to be the mainstay for treatment of this BC, which lacks targetable markers. In this context, microRNAs have been described to have an important role. The aim of this work was to elucidate the function of miR-503-5p in doxorubicin resistance in TNBC. Methods: miR-503-5p expression was evaluated in the TNBC cell line with acquired resistance to doxorubicin (MDA-MB-231R) and its parental cell line (MDA-MB-231), by qRT-PCR. Studies of gain/loss of function of miR-503-5p were carried out in MDA-MB-231 and MDA-MB-231R cells by transient transfection of mimics and inhibitors. Cells were treated with doxorubicin, and viability was measured by flow cytometry and MTT assay. The role of miR-503-5p was also evaluated in vivo by Chicken Chorioallantoic Membrane (CAM) assay. MDA-MB-231 cells transfected with miR-503-5p mimic or scramble miRNA were inoculated onto the CAM of fertilized chicken eggs. After 48 hours, tumours were treated with doxorubicin or supplemented media for 48 hours and tumour growth was measured. miR-503-5p expression was quantified by qRT-PCR in a retrospective cohort of 74 TNBC patients treated with anthracycline + taxane regimens. Overall survival analysis for miR-503-5p in TNBC patients from METABRIC dataset was evaluated by the KM plotter online tool. Results: miR-503-5p was significantly upregulated in the resistant MDA-MB-231R TNBC cell line when compared to its parental cell line MDA-MB-231 (̃3.5-fold; p< 0.0001). Then, gain/loss function assays showed that upregulation of miR-503-5p in MDA-MB-231 cells increased resistance to doxorubicin ( p< 0.0001) and its downregulation in MDA-MB-231R cells had the opposite effect ( p< 0.0001). Moreover, the role of miR-503-5p was also confirmed in the CAM assay in vivo model, where miR-503-5p overexpression inhibited the effect of doxorubicin. In our cohort of patients, miR-503-5p expression levels in core biopsies sampled before preoperative chemotherapy were associated with residual cancer burden (RCB). miR-503-5p expression was significantly higher in patients with poor response to chemotherapy (RCB II and III; median, 95% CI: 0.00055, 0.00024 - 0.00136) than in patients with good response (RCB 0 and I; median, 95% CI: 0.00018, 0.00011 - 0.00034; p = 0.036). Moreover, we confirmed that TNBC patients with high expression of miR-503-5p had worse overall survival than patients with low expression ( p= 0.016). Conclusions: We identified miR-503-5p as a modulator of doxorubicin resistance in TNBC. Our in vitro findings are supported by the clinical data of TNBC patients and in vivo assays. Hence, the inhibition of miR-503-5p may be a promising strategy to improve chemotherapeutic efficacy. Moreover, the expression levels of miR-503-5p may be used as a biomarker for therapy response in TNBC.

e12600 Background: In early-stage HER2+ breast cancer (BC), escalation or de-escalation of systemic treatment is an unmet need. Integration of promising biomarkers into risk scoring will further help progressing in the field. We aim to develop a prognostic signature that integrates two miRNAs (A and B) and quantitative and qualitative clinical variables in patients diagnosed with HER2+ BC. Methods: This study was conducted in a retrospective cohort of 45 HER2+ BC patients. Patients received standard treatment for localized disease. We calculated a prognostic signature for disease-free survival (DFS) using principal components analysis for mixed data combining clinicopathological data (Ki67 and axillary lymph node [pN0, pN1, pN2, pN3]) and expression of two microRNAs (we used mir-16 as housekeeping). Multiple DFS prognostic signatures were calculated and goodness of fit was evaluated by means of Akaike’s Information Criterion (AIC) to perform Cox model selection. Signature was then dichotomized into “high risk” and “low risk” using maximally selected Log-Rank statistics by Hothorn and Lausen, as method for optimal cut-off. Kaplan-Meier curves, Log-Rank test and Breslow test were used to ascertain statistical differences in the probability of DFS between high and low risk groups. MiRNA targeted genes were selected and used to perform functional enrichment analysis with the KEGG pathway database. To select significant terms/pathways, p-values were adjusted by the Benjamini-Hochberg method (p < 0.05). Results: MiR-A and miR-B expression was higher in primary tumor of patients who relapse compared to those free of disease after treatment (p = 0.018 and 0.004, respectively). Both miRNAs were strongly correlated (r = 0.84). This signature was significantly associated with relapse of the disease (HR 1.72; CI 95%: 1.243–2.382; p < 0.01, AIC = 114.02). The optimal cut-off of this score was obtained and patients were classified into high and low risk groups. Median DFS of the high-risk was 44 months while it has been not reached yet across the low risk after a median follow-up of 67 months (HR 8.39; p = 0.005, AIC = 111.784). Significant differences in survival between both groups were found (log rank test p < 0.001; Breslow test p = 0.002). miR-A and miR-B functional enrichment analysis returned 55 significant pathways. Interestingly, P53 pathway, apoptosis and cell cycle which are closely related to tumorigenesis and treatment response, were in the top 5 enriched pathways. Conclusions: Both miRNAs included in this signature are related to important biological pathways associated to BC progression. Our new prognostic signature identifies patients with early-stage, HER2+ BC who might be candidates for escalated or de-escalated systemic treatment. This signature was able to classify patients for DFS in high or low risk groups at the moment of BC diagnosis. Further investigations to validate the value of this new signature are on-going.

Background: NF-κB signalling appears deregulated in breast tumours. The purpose of this study was to determine whether the non-canonical NF-κB pathway, is activated in oestrogen receptor positive (ER+) breast cancer, to identify any correlation between its activity and the clinico-pathological phenotype and to explore whether NF-κB2 and RelB subunits and/or any of their target genes might be used as a predictive marker. Methods: Two independent cohorts of ER+ early breast cancer patients treated with adjuvant endocrine therapy were included in the study. Activation of RelB and NF-κB2 subunits was determined in a training set of 121 patients by measuring DNA-binding activities in nuclear extracts from fresh frozen specimens by an ELISA-based assay. Samples of 15 ER− breast cancer patients were also included in the study. In a large validation cohort of 207 patients, nuclear immunostaining of RelB and NF-κB2 on formalin-fixed paraffin-embedded specimens was performed. Statistical correlation within clinico-pathological factors, disease-free survival (DFS) and overall survival (OS) was evaluated. Publicly available gene expression and survival data have been interrogated aimed to identify target genes. Results: Activation of NF-κB2 and RelB was found in 53.7 and 49.2% of the 121 ER+ tumours analysed, with similar levels to ER− breast tumours analysed in parallel for comparisons. In the validation cohort, we obtained a similar proportion of cases with activation of NF-κB2 and RelB (59.9 and 32.4%), with a 39.6% of co-activation. Multiplexing immunofluorescence in breast cancer tissue confirmed an inverse spatial distribution of ER with NF-κB2 and RelB nuclear expression in tumour cells. Interestingly, NF-κB2 and RelB mRNA expression was inversely correlated with ER gene (ESR1) levels (P

MicroRNAs (miRNAs) are small non-coding RNA molecules that critically regulate the expression of genes. MiRNAs are involved in physiological cellular processes; however, their deregulation has been associated with several pathologies, including cancer. In human breast cancer, differently expressed levels of miRNAs have been identified from those in normal breast tissues. Moreover, several miRNAs have been correlated with pathological phenotype, cancer subtype and therapy response in breast cancer. The resistance to therapy is increasingly a problem in patient management, and miRNAs are emerging as novel therapeutic targets and potential predictive biomarkers for treatment. This review provides an overview of the current situation of miRNAs in breast cancer, focusing on their involvement in resistance and the circulating miRNA. The mechanisms of therapeutic resistance regulated by miRNAs, such as the regulation of receptors, the modification of enzymes of drug metabolism, the inhibition of cell cycle control or pro-apoptotic proteins, the alteration of histone activity and the regulation of DNA repair machinery among others, are discussed for breast cancer clinical subtypes. Additionally, in this review, we summarize the recent knowledge that has established miRNA detection in peripheral body fluids as a suitable biomarker. We review the detection of miRNA in liquid biopsies and its implications for the diagnosis and monitoring of breast cancer. This new generation of cancer biomarkers may lead to a significant improvement in patient management.

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&rsquo, 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.

Angiogenesis process contributes to the pathogenesis of B-cell chronic lymphocytic leukemia (B-CLL) being the levels of VEGFA and bFGF higher in patients than in healthy controls. Our aim was to evaluate the implication of angiogenesis factors genetic variants in the predisposition to B-CLL and their association with clinical factors and survival. We performed a population-based case-control study in 224 Spanish B-CLL patients and 476 healthy randomly selected controls to evaluate susceptibility to developing B-CLL. Six polymorphisms were evaluated: rs1109324, rs1547651, rs3025039 (+936 C>T), rs833052 of the VEGFA gene, rs1449683 (c.233C>T) of the bFGF gene and (−710 C>T) of the VEGFR1 gene. The association between clinical parameters and patient outcome was analyzed. Carriers of the CT/TT variants of rs3025039 showed a significant protective effect against developing B-CLL. The CT/TT variants of rs1449683 show a tendency towards the development of the disease and the same variants associated significantly with higher genetic risk and with reduced disease free survival. Moreover, the association persisted in the early-stage disease subgroup. Our study provides evidence of the protective effect of the T/- rs3025039 VEGFA variant against B-CLL development and the association of CT/TT variants of the rs1449683 bFGF gene with genetic risk and an adverse survival.

Background Pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) in triple-negative breast cancer (TNBC) varies between 30 and 40% approximately. To provide further insight into the prediction of pCR, we evaluated the role of an epigenetic methylation-based signature. Methods Epigenetic assessment of DNA extracted from biopsy archived samples previous to NAC from TNBC patients was performed. Patients included were categorized according to previous response to NAC in responder (pCR or residual cancer burden, RCB = 0) or non-responder (non-pCR or RCB > 0) patients. A methyloma study was performed in a discovery cohort by the Infinium HumanMethylation450 BeadChip (450K array) from Illumina. The epigenetic silencing of those methylated genes in the discovery cohort were validated by bisulfite pyrosequencing (PyroMark Q96 System version 2.0.6, Qiagen) and qRT-PCR in an independent cohort of TN patients and in TN cell lines. Results Twenty-four and 30 patients were included in the discovery and validation cohorts, respectively. In the discovery cohort, nine genes were differentially methylated: six presented higher methylation in non-responder patients (LOC641519, LEF1, HOXA5, EVC2, TLX3, CDKL2) and three greater methylation in responder patients (FERD3L, CHL1, and TRIP10). After validation, a two-gene (FER3L and TRIP10) epigenetic score predicted RCB = 0 with an area under the ROC curve (AUC) = 0.905 (95% CI = 0.805–1.000). Patients with a positive epigenetic two-gene score showed 78.6% RCB = 0 versus only 10.7% RCB = 0 if signature were negative. Conclusions These results suggest that pCR in TNBC could be accurately predicted with an epigenetic signature of FERD3L and TRIP10 genes. Further prospective validation of these findings is warranted. Electronic supplementary material The online version of this article (10.1186/s13148-019-0626-0) contains supplementary material, which is available to authorized users.

Taxanes are standard therapy in clinical practice for metastatic breast cancer; however, primary or acquired chemoresistance are a common cause of mortality. Breast cancer patient-derived xenografts (PDX) are powerful tools for the study of cancer biology and drug treatment response. Specific DNA methylation patterns have been associated to different breast cancer subtypes but its association with chemoresistance remains unstudied. Aiming to elucidate docetaxel resistance mechanisms, we performed genome-wide DNA methylation in breast cancer PDX models, including luminal and triple-negative breast cancer (TNBC) models sensitive to docetaxel, their matched models after emergence of chemoresistance and residual disease after short-term docetaxel treatment. We found that DNA methylation profiles from breast cancer PDX models maintain the subtype-specific methylation patterns of clinical samples. Two main DNA methylation clusters were found in TNBC PDX and remain stable during the emergence of docetaxel resistance; however, some genes/pathways were differentially methylated according to docetaxel response. A DNA methylation signature of resistance able to segregate TNBC based on chemotherapy response was identified. Transcriptomic profiling of selected sensitive/resistant pairs and integrative analysis with methylation data demonstrated correlation between some differentially methylated and expressed genes in docetaxel-resistant TNBC PDX models. Multiple gene expression changes were found after the emergence of docetaxel resistance in TNBC. DNA methylation and transcriptional changes identified between docetaxel-sensitive and -resistant TNBC PDX models or residual disease may have predictive value for chemotherapy response in TNBC. Implications: Subtype-specific DNA methylation patterns are maintained in breast cancer PDX models. While no global methylation changes were found, we uncovered differentially DNA methylated and expressed genes/pathways associated with the emergence of docetaxel resistance in TNBC.

Natural killer (NK) cells can orchestrate effective antitumor immunity. The presence of tumor-infiltrating NK cells in diagnostic biopsies predicts pathologic complete response (pCR) to HER2-specific therapeutic antibodies in patients with primary breast cancer. Here, we analyzed whether diversity in circulating NK cells might influence tumor infiltration and HER2-specific therapeutic antibody efficacy. We found that numbers of circulating CD57+ NK cells inversely correlated with pCR to HER2-specific antibody treatment in patients with primary breast cancer independently of age, traditional clinicopathologic factors, and CD16A 158F/V genotype. This association was uncoupled from the expression of other NK-cell receptors, the presence of adaptive NK cells, or changes in major T-cell subsets, reminiscent of cytomegalovirus-induced immunomodulation. NK-cell activation against trastuzumab-coated HER2+ breast cancer cells was comparable in patients with high and low proportions of CD57+ NK cells. However, circulating CD57+ NK cells displayed decreased CXCR3 expression and CD16A-induced IL2-dependent proliferation in vitro. Presence of CD57+ NK cells was reduced in breast tumor–associated infiltrates as compared with paired peripheral blood samples, suggesting deficient homing, proliferation, and/or survival of NK cells in the tumor niche. Indeed, numbers of circulating CD57+ were inversely related to tumor-infiltrating NK-cell numbers. Our data reveal that NK-cell differentiation influences their antitumor potential and that CD57+ NK cells may be a biomarker useful for tailoring HER2 antibody–based therapeutic strategies in breast cancer.

Natural killer (NK) cells can orchestrate effective antitumor immunity. The presence of tumor-infiltrating NK cells in diagnostic biopsies predicts pathologic complete response (pCR) to HER2-specific therapeutic antibodies in patients with primary breast cancer. Here, we analyzed whether diversity in circulating NK cells might influence tumor infiltration and HER2-specific therapeutic antibody efficacy. We found that numbers of circulating CD57

UNLABELLED Chemotherapy treatment is the standard in triple negative breast cancers, a cancer subgroup which lacks a specific target. The mechanisms leading to the response, as well as any markers that allow the differentiation between responder and non-responder groups prior to treatment are unknown. In parallel, miRNAs can act as oncogenes or tumor suppressors and there is evidence of their involvement in promoting resistance to anticancer drugs. Therefore we hypothesized that changes in miRNA expression after doxorubicin treatment may also be relevant in treatment response. OBJECTIVE To study miRNAs that are differentially expressed in response to doxorubicin treatment. METHODS One luminal-A and two triple negative, breast cancer cell lines were exposed to doxorubicin. Microarray analysis was performed to identify the common and differentially modified miRNAs. Genes and pathways that are theoretically regulated by these miRNAs were analyzed. RESULTS Thirteen miRNAs common to all three lines were modified, in addition to 25 that were specific to triple negative cell lines, and 69 that changed only in the luminal-A cell line. This altered expression pattern seemed to be more strongly related to the breast cancer subgroup than to the treatment. The analysis of target genes revealed that cancer related pathways were the most affected by these miRNAs, moreover many of them had been previously related to chemotherapy resistance; thus suggesting follow-up studies. Additionally, through functional assays, we showed that miR-548c-3p is implicated in doxorubicin-treated MCF-7 cell viability, suggesting a role for this miRNA in resistance.

Background: Breast cancer (BC) is a heterogeneous disease. HER2+ BC represents between 15-20% of cases. Trastuzumab, a monoclonal antibody, has been successfully improved clinical benefits in both localized and advanced setting. Despite this evidence, many patients experience resistance to therapy. The objective of this study is to analyze AXL receptor as a potential mechanism of resistance and its implication as a prognostic factor. Methods: We used three breast cancer cell lines with acquired resistance to Trastuzumab. Resistant models were generated by treating parental cells (AU565, SKR3, BT474) with constant dose of Trastuzumab (15μg/mL) for 6 months. Cell viability was estimated by MTT assay. Proteins were assessed by Western blot and genes by qRT-PCR. AXL was downregulated by siRNA and a selective tyrosine kinase (TK) AXL inhibitor (TP-0903). Proteins interaction was assessed by immunoprecipitation and Duolink®PLA. The prognostic value of AXL was evaluated in primary tumor in a cohort of HER2+ BC patients treated with Trastuzumab plus chemotherapy from our center (n=33). Results: Acquired resistant cell lines (RCLs) maintained HER2 amplification. RCLs were more proliferative than sensitive parental cell lines. There was an important up-regulation of AXL (>2.5 fold-change) and epithelial-mesenchymal transition markers (VIM, CDH2, CTNNB1 and FN1) in RCLs (p Citation Format: Anna Adam-Artigues, Eduardo Tormo, Raimundo Cervera, Federico Rojo, Alejandro Pérez-Fidalgo, Sandra Zazo, Paula González-Alonso, Cristina Hernándo, María Teresa Martínez, Valentina Gambardella, Jesús Poveda, Soraya Simón, Belén Ortega, Santiago Moragón, Ana Rovira, Joan Albanell, Octavio Burgués, Begoña Bermejo, Pilar Eroles, Ana Lluch, Juan Miguel Cejalvo. AXL-HER2 dimer as mechanism of anti-HER2 acquired resistance in HER2 amplified brest cancer models: A new step towards precision medicine [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-03-05.

Poly (ADP-ribose) polymerase (PARP) inhibitors have shown promising results in Breast Cancer (BRCA) deficient breast cancer, but not in molecularly unselected patient populations. Two lines of research in this field are needed: the identification of novel subsets of patients that could potentially benefit from PARP inhibitors and the discovery of suitable targeted therapies for combination strategies.We tested PARP inhibition, alone or combined with the anti-HER2 antibody trastuzumab on HER2+ breast cancer. We used two PARP inhibitors in clinical development, olaparib and rucaparib, as well as genetic downmodulation of PARP-1 for in vitro studies. DNA damage was studied by the formation of γH2AX foci and comet assay. Finally, the in vivo anti-tumour effect of olaparib and trastuzumab was examined in nude mice subcutaneously implanted with BT474 cells.In a panel of four HER2 overexpressing breast cancer cell lines, both olaparib and rucaparib significantly decreased cell growth and enhanced anti-tumour effects of trastuzumab. Cells exposed to olaparib and trastuzumab had greater DNA damage than cells exposed to each agent alone. Mechanistic exploratory assays showed that trastuzumab downmodulated the homologous recombination protein proliferating cell nuclear antigen (PCNA). Combination treatment in the BT474 xenograft model resulted in enhanced growth inhibition, reduced tumour cell proliferation, and increased DNA damage and apoptosis.Taken together, our results show that PARP inhibition has antitumour effects and increases trastuzumab activity in HER2 overexpressing breast cancer. These findings make this novel combination a promising strategy for clinical development.

The EGFR has been associated with the pathogenesis and progression of breast cancer. Treatment based on an EGFR target is emerging as a promising option, especially in combination with conventional therapies. Unfortunately, there are no validated predictor biomarkers, and combinatorial treatments are meeting new resistance.The purpose of this review is to summarize the existing treatments and the current research based on targeting the EGFR pathway.The existing EGFR treatments in breast cancer have shown limited benefit. The combination of the monoclonal antibody cetuximab and platinum salts achieves a 15 - 20% response rate. The effectiveness of tyrosine kinase inhibitors is not completely clear, showing modest or no benefits. Gefitinib treatment has offered some promising results in estrogen receptor + breast cancer. However, it has not been identified as a predictive factor for the appropriate selection of patients. Radioimmunotherapy with anti-EGFR radiolabeled antibodies is a promising strategy in BRCA-mutated breast cancer, but it still requires clinical confirmation. Nevertheless, the crosstalk between pathways frequently leads to treatment resistance. Current research is focused on increasing knowledge about the mechanisms of response and the discovery of predictive markers. Targeting several pathways simultaneously and a correct selection of patients seem essential.

There is growing interest in delivering genomically informed cancer therapy. Our aim was to determine the concordance of genomic alterations between primary and recurrent breast cancer. Targeted next-generation sequencing was performed on formalin-fixed paraffin-embedded (FFPE) samples, profiling 3,320 exons of 182 cancer-related genes plus 37 introns from 14 genes often rearranged in cancer. Point mutations, indels, copy-number alterations (CNA), and select rearrangements were assessed in 74 tumors from 43 patients (36 primary and 38 recurrence/metastases). Alterations potentially targetable with established or investigational therapeutics were considered “actionable.” Alterations were detected in 55 genes (mean 3.95 alterations/sample, range 1–12), including mutations in PIK3CA, TP53, ARID1A, PTEN, AKT1, NF1, FBXW7, and FGFR3 and amplifications in MCL1, CCND1, FGFR1, MYC, IGF1R, MDM2, MDM4, AKT3, CDK4, and AKT2. In 33 matched primary and recurrent tumors, 97 of 112 (86.6%) somatic mutations were concordant. Of identified CNAs, 136 of 159 (85.5%) were concordant: 37 (23.3%) were concordant, but below the reporting threshold in one of the matched samples, and 23 (14.5%) discordant. There was an increased frequency of CDK4/MDM2 amplifications in recurrences, as well as gains and losses of other actionable alterations. Forty of 43 (93%) patients had actionable alterations that could inform targeted treatment options. In conclusion, deep genomic profiling of cancer-related genes reveals potentially actionable alterations in most patients with breast cancer. Overall there was high concordance between primary and recurrent tumors. Analysis of recurrent tumors before treatment may provide additional insights, as both gains and losses of targets are observed. Mol Cancer Ther; 13(5); 1382–9. ©2014 AACR.

Background Breast cancer (BC) is a heterogeneous disease. HER2+ BC represents between 15-30% of cases. Trastuzumab (T), a monoclonal antibody, has been successfully improved clinical benefits in both adjuvant and in metastatic settings. Despite this evidence, many patients experience resistance to therapy. The objective of this study is to assess AXL as a potential mechanism of resistance and its implication as a prognostic factor. Methods We used three cell lines with acquired resistance to T. Resistant models were generated by treating parental cells (AU565, SKR3, BT474) with constant dose of T (15mg/mL) for 6 months. Cell viability was estimated by MTT assay. Proteins were assessed by Western blot (WB) and flow cytometry and genes by qRT-PCR. AXL was downregulated by siRNA and a selective AXL inhibitor (TP-0903). The prognostic value of AXL was evaluated in primary tumor in a cohort of HER2+ BC patients treated with T in adjuvant setting from Hospital Clinico Valencia (n = 33). Results Acquired resistant cell lines (RCL) maintained HER2 overexpression. Cells were more proliferative and presented an increase in stem cell-like characteristics compared to sensitive parental cell lines. There was an important up-regulation of AXL (>2.5 fold-change) and epithelial-mesenchymal transition markers (VIM, CDH2, and FN1) in RCL (p Conclusions Our results suggest: 1) RCL were more proliferative, more mesenchymal-like and stem cell-like properties; 2) AXL was a potential mechanism of secondary resistance to T; 3) Combination therapy with AXL inhibitor plus T restored sensitivity in in vitro model with AXL overexpression; 4) AXL expression was associated with relapse in HER2+ BC patients. These results showed AXL as a prognostic factor and a potential therapeutic target in HER2+ patients with resistance to T. Legal entity responsible for the study The authors. Funding Has not received any funding. Disclosure A. Lluch: Advisory / Consultancy: Novartis; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Roche/Genentech; Advisory / Consultancy: Eisai; Advisory / Consultancy: Celgene. All other authors have declared no conflicts of interest.

The question of whether anesthetic, analgesic or other perioperative intervention during cancer resection surgery might influence long-term oncologic outcomes has generated much attention over the past 13 years. A wealth of experimental and observational clinical data have been published, but the results of prospective, randomized clinical trials are awaited. The European Union supports a pan-European network of researchers, clinicians and industry partners engaged in this question (COST Action 15204: Euro-Periscope). In this narrative review, members of the Euro-Periscope network briefly summarize the current state of evidence pertaining to the potential effects of the most commonly deployed anesthetic and analgesic techniques and other non-surgical interventions during cancer resection surgery on tumor recurrence or metastasis. Funding Agencies|European Union [COST ACTION 15204]

A subset of HER2+ breast cancer patients manifest clinical resistance to trastuzumab. Recently, miR-26a and miR-30b have been identified as trastuzumab response regulators, and their target gene CCNE2 seems to play an important role in resistance to trastuzumab therapy. Cell viability was evaluated in trastuzumab treated HER2+ BT474 wt (sensitive), BT474r (acquired resistance), HCC1954 (innate resistance), and MDA-MB-231 (HER2−) cell lines, and the expression of miR-26a, miR-30b, and their target genes was measured. BT474 wt cell viability decreased by 60% and miR-26a and miR-30b were significantly overexpressed (~3-fold, p = 0.003 and p = 0.002, respectively) after trastuzumab treatment, but no differences were observed in resistant and control cell lines. Overexpression of miR-30b sensitized BT474r cells to trastuzumab (p = 0.01) and CCNE2, was significantly overexpressed after trastuzumab treatment in BT474r cells (p = 0.032), but no significant changes were observed in sensitive cell line. When CCNE2 was silenced BT474r cell sensitivity to trastuzumab increased (p = 0.03). Thus, the molecular mechanism of trastuzumab action in BT474 cell line may be regulated by miR-26a and miR-30b and CCNE2 overexpression might play an important role in acquired trastuzumab resistance in HER2+ breast cancer given that resistance was diminished when CCNE2 was silenced.

[Purpose]: Trastuzumab-emtansine (T-DM1) is a standard treatment in advanced HER2-positive breast cancer. However, resistance inevitably occurs. We aimed to identify mechanisms of acquired T-DM1 resistance. [Experimental Design]: HER2-positive breast cancer cells (HCC1954, HCC1419, SKBR3, and BT474) were treated in a pulse-fashion with T-DM1 to induce a resistant phenotype. Cellular and molecular effects of T-DM1 in parental versus resistant cells were compared. CDK1 kinase activity and cyclin B1 expression were assayed under various conditions. Genetic modifications to up- or downregulate cyclin B1 were conducted. Effects of T-DM1 on cyclin B1 levels, proliferation, and apoptosis were assayed in human HER2-positive breast cancer explants. [Results]: We obtained three cell lines with different levels of acquired T-DM1 resistance (HCC1954/TDR, HCC1419/TDR, and SKBR3/TDR cells). HER2 remained amplified in the resistant cells. Binding to HER2 and intracellular uptake of T-DM1 were maintained in resistant cells. T-DM1 induced cyclin B1 accumulation in sensitive but not resistant cells. Cyclin B1 knockdown by siRNA in parental cells induced T-DM1 resistance, while increased levels of cyclin B1 by silencing cdc20 partially sensitized resistant cells. In a series of 18 HER2-positive breast cancer fresh explants, T-DM1 effects on proliferation and apoptosis paralleled cyclin B1 accumulation. [Conclusions]: Defective cyclin B1 induction by T-DM1 mediates acquired resistance in HER2-positive breast cancer cells. These results support the testing of cyclin B1 induction upon T-DM1 treatment as a pharmacodynamic predictor in HER2-positive breast cancer., This work was supported by ISCiii (CIBERONC CB16/12/00481, RD12/0036/0051, RD12/0036/0070, RD12/0036/0003, PIE15/00008, PI13/00864, PI15/00146, PI15/00934, PI15/01617, PT13/0010/0005), Generalitat de Catalunya (2014 SGR 740), and the >Xarxa de Bancs de tumors sponsored by Pla Director d'Oncologia de Catalunya (XBTC). MINECO through BFU2015-71371-R grant supported work in A. Pandiella's laboratory. Our work was supported by the EU through the regional funding development program (FEDER). P. González-Alonso was supported by Fundación Conchita Rábago de Jiménez Díaz grant.

Metformin, a drug approved for diabetes type II treatment, has been associated with a reduction in the incidence of breast cancer and metastasis and increased survival in diabetic breast cancer patients. High levels of miR-26a expression have been proposed as one of the possible mechanisms for this effect; likewise, this miRNA has also been associated with survival/apoptosis processes in breast cancer. Our aim was to evaluate if miR-26a and some of its targets could mediate the effect of metformin in breast cancer. The viability of MDA-MB-231, MDA-MB-468, and MCF-7 breast cancer cell lines was evaluated with an MTT assay after ectopic overexpression and/or downregulation of miR-26a. Similarly, the expression levels of the miR-26a targets CASP3, CCNE2, ABL2, APAF1, XIAP, BCL-2, PTEN, p53, E2F3, CDC25A, BCL2L1, MCL-1, EZH2, and MTDH were assessed by quantitative polymerase chain reaction (PCR). The effect of metformin treatment on breast cancer cell viability and miR-26a, BCL-2, PTEN, MCL-1, EZH2, and MTDH modulation were evaluated. Wound healing experiments were performed to analyze the effect of miR-26a and metformin treatment on cell migration. MiR-26a overexpression resulted in a reduction in cell viability that was partially recovered by inhibiting it. E2F3, MCL-1, EZH2, MTDH, and PTEN were downregulated by miR-26a and the PTEN (phosphatase and tensin homolog) protein was also reduced after miR-26a overexpression. Metformin treatment reduced breast cancer cell viability, increased miR-26a expression, and led to a reduction in BCL-2, EZH2, and PTEN expression. miR-26a inhibition partly prevents the metformin viability effect and the PTEN and EZH2 expression reduction. Our results indicate that metformin effectively reduces breast cancer cell viability and suggests that the effects of the drug are mediated by an increase in miR-26a expression and a reduction of its targets, PTEN and EHZ2 Thus, the use of metformin in breast cancer treatment constitutes a promising potential breast cancer therapy.

Background: Overexpression and amplification of the human epidermal growth factor receptor 2 (HER2) occur in 20% of total breast carcinomas. HER2-overexpression is implicated in disease initiation and progression and associated with poor prognosis. Trastuzumab, a humanized monoclonal antibody, is the standard HER2-targeted therapy for early and metastatic HER2-amplified breast cancer patients. Trastuzumab has significantly increased clinical benefit in HER2+ metastatic and adjuvant settings; however, it is not effective for many patients due to primary or acquired resistance to the drug. During the last decade, many studies have revealed a number of novel molecular traits of HER2+ breast cancer, allowing us to uncover the molecular mechanisms involved in trastuzumab resistance and develop strategies to overcome resistance to therapy. Objective: In this review, we comprehensively addressed the current achievements in preclinical studies; we discussed molecular mechanisms of acquired trastuzumab resistance in HER2+ breast cancer models and potential therapeutic approaches based on the molecular features for HER2+ breast cancer. Conclusion: Enhanced understanding of the molecular profiles in HER2+ breast cancer may lead to the identification of novel biomarkers for the development of diagnostic approaches and improvement of therapeutic targets for the prevention and treatment of trastuzumab resistant HER2+ breast cancer.

Diverse polymorphisms have been associated with the predisposition to develop cancer. On fewer occasions, they have been related to the evolution of the disease and to different responses to treatment. Previous studies of our group have associated polymorphisms on genes related to oxidative stress (rs3736729 on GCLC and rs207454 on XDH) and DNA damage repair (rs1052133 on OGG1) with a predisposition to develop breast cancer. In the present work, we have evaluated the hypothesis that these polymorphisms also play a role in a patient’s survival. A population-based cohort study of 470 women diagnosed with primary breast cancer and a median follow up of 52.44 months was conducted to examine the disease-free and overall survival in rs3736729, rs207454 and rs1052133 genetic variants. Adjusted Cox regression analysis was used to that end. The Kaplan-Meier analysis shows that rs3736729 on GCLC presents a significant association with disease-free survival and overall survival. The polymorphisms rs1052133 on OGG1 and rs207454 on XDH show a trend of association with overall survival. The analysis based on hormonal receptor status revealed a stronger association. The CC genotype on rs207454 (XDH) was significantly associated with lower time of disease free survival (p = 0.024) in progesterone receptor negative (PGR−) patients and rs3736729 (GCLC) was significantly associated with disease free survival (p = 0.001) and overall survival (p = 0.012) in the subgroup of estrogen receptor negative (ER−) patients. This work suggests that unfavorable genetic variants in the rs207454 (XDH) and rs3736729 (GCLC) polymorphisms may act as predictors of the outcome in negative progesterone receptor and negative estrogen receptor breast cancer patients, respectively.

BACKGROUND Poly(ADP-ribose)polymerase-1 (PARP-1) is a highly promising novel target in breast cancer. However, the expression of PARP-1 protein in breast cancer and its associations with outcome are yet poorly characterized. PATIENTS AND METHODS Quantitative expression of PARP-1 protein was assayed by a specific immunohistochemical signal intensity scanning assay in a range of normal to malignant breast lesions, including a series of patients (N = 330) with operable breast cancer to correlate with clinicopathological factors and long-term outcome. RESULTS PARP-1 was overexpressed in about a third of ductal carcinoma in situ and infiltrating breast carcinomas. PARP-1 protein overexpression was associated to higher tumor grade (P = 0.01), estrogen-negative tumors (P < 0.001) and triple-negative phenotype (P < 0.001). The hazard ratio (HR) for death in patients with PARP-1 overexpressing tumors was 7.24 (95% CI; 3.56-14.75). In a multivariate analysis, PARP-1 overexpression was an independent prognostic factor for both disease-free (HR 10.05; 95% CI 5.42-10.66) and overall survival (HR 1.82; 95% CI 1.32-2.52). CONCLUSIONS Nuclear PARP-1 is overexpressed during the malignant transformation of the breast, particularly in triple-negative tumors, and independently predicts poor prognosis in operable invasive breast cancer.

INTRODUCTION: Pathologic complete response (pCR) is associated with long-term survival and is considered as the primary endpoint in neoadjuvant trials. Definition of pCR includes patients without residual disease of the breast, however the presence of nodal metastasis, minimal residual cellularity and residual in situ carcinoma were not consistently defined as pCR. These observations, lead Symmans et al to construct a new prognostic index, the RCBI, in which these important issues were incorporated. RCBI is classified into 4 different response subgroups, from RCB-0 or pCR to RCB-III or absence of response. The aim of our study was to assess the prognostic value for recurrence free survival of the RCBI in a cohort of unselected breast cancer patients treated in our institution. PATIENTS AND METHODS: We performed a retrospective evaluation of samples of breast cancer patients treated with neoadjuvant treatment. RCBI was assessed by two highly trained pathologists. Patients included had a histological diagnosis of breast carcinoma before neoadjuvant treatment and were considered candidate for neoadjuvant therapy. Clinical variables including date and type of recurrence were obtained from clinical records. Prognostic accuracy of RCBI index was evaluated by comparison of the Kaplan-Meier survival curves of the 4 different groups of response by RCBI. Differences were assessed with log-rank. RESULTS: Samples from 70 patients treated in the neoadjuvant setting from January 2003 to December 2006 were included in the analysis. Median age was 54.6 years (range 31–80), histhologic subtype was ductal carcinoma (87.1%), lobular carcinoma (8.5%), and other (4.2%). In biopsy, rate of estrogen receptor positive was 72.7%, progesterone receptor positive 62.1%, and rate of HER2 overexpression was 26.2%. Neoadjuvant therapy administered was anthracycline+taxanes chemotherapy (CT )in both sequential or combination schedules in 71.4%, anthracycline-based CT in 15.7%, and other in 12.9%. Most patients received from 6–10 cycles of neoadjuvant CT. 3 patients treated with only 4 cycles received adjuvant complementary CT. All patients with hormone-sensible tumors received adjuvant endocrine therapy and 20 patients received adjuvant trastuzumab. Number of responses by RCB-group was 5 patients (7.1%) with RCB-0, 12 patients (17.1%) with RCB-I, 35 (50%) with RCB-II, and 18 (25.7%) with RCB-III. With a median follow-up of 41.2 months (range 12.7−120.9 months) 22 patients (31.4%) have relapsed. Ratio of events/patients in each RCB group was 0/5 in RCB-0, 2 /12 in RCB-I, 8/35 in RCB-II and 15/18 in RCB-III. Differences in recurrence-free survival in each group was statistically significant with p=0.0002. CONCLUSIONS: Our results suggest that RCBI might be an appropriate prognostic tool to predict disease-free survival in a non-selected population of breast cancer patients. Further validation of our results with a bigger sample size is needed. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-14-05.

Introduction: Discordance in expression of estrogen (ER) or progesterone receptors (PgR) and HER2 has been previously described in several studies, having this discordance an important impact on therapeutic approach or even in survival. However it is unclear whether discordance is a reflex of a clonal differentiation to a more aggressive biological tumour or the consequence of technical biases or inter-explorer variability. We aimed to assess the role of technique biases in observed discordance between primary tumour (PT) and recurrent tumour (RT) by analyzing discordance in two different situations: routine versus optimal conditions. Patients and methods: We conducted a retrospective study in patients (pts) diagnosed with a recurrent breast cancer in the Hospital Clinico of Valencia between January 2000 and June 2010. All patients had a previous histological diagnose of the PT and all underwent a second histological study of the RT. Discordance was assessed in terms of hormone-sensibility (HS) (any ER or PgR +) vs hormone-resistance (HR) (ER-/PgR -) and triple negativity (TN) (ER-, PgR-, HER2−) vs non-TN (any positive). Routine conditions were referred to the immunohistochemistry (IHC) assessment of the normal practice on the base of which therapeutic decisions were made. Routine conditions were performed in the Pathology Department of our institution but PT and RT were usually evaluated at different timing and ocasionally by different pathologists. In order to assess potential laboratory biases we repeated IHC analysis under optimal conditions. For these optimal conditions analyses, paired samples from both PT and RT were reassessed at the same time and tests were performed in the same way. Final determination of the results was made by two highly trained pathologists and in case of disagreement in any determination, both explorers re-assessed the sample at the same time. We evaluated discordance between PT and RT under both conditions, and the accuracy of determinations in PT or RT between both conditions. Results: 128 paired samples (from 64 different pts) were analysed. Median age of the series was 48.5 years (range 27–83). Recurrences were loco-regional in 14 pts (21.9%) and distant in 50 pts (78.1%). RT tissue was obtained from skin and soft-tissues in 18 pts (28.1%), lung in 11 (17.2%), bone in 10 (15.6%), lymph nodes in 10 (15.6%), pleura/peritoneum in 9 (14.1%) and liver in 6 (9.4%). Discordant cases between PT an RT in terms of HS/HR were 30.4% in routine conditions and 9.8% in optimal conditions. In terms of TN/non-TN were 14.3% in routine vs 8.2% in optimal conditions. Accuracy in results HS/HR between routine and optimal conditions was 80.7% in PT and 76.0% in RT. In results of TN/non-TN accuracy between both conditions was 94.2% in PT and 87.2% in RT. Conclusions: Results suggest that an important rate of discordance observed in routine conditions might be strongly influenced by technique biases. However, changes observed in optimal conditions with 9.8% discordance in HS/HR and 8.2% in TN/non-TN suggest that in a small proportion of tumours, observed discordance might be explained by biological mechanisms. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-11-06.

e12658Background: Prediction of response to neoadjuvant chemotherapy (NAC) in triple-negative breast cancer (TNBC) patients is an unmet medical need. NAC with anthracyclines/taxanes achieves about ...

Breast cancer is a heterogeneous disease with different morphologies, molecular profiles, clinical behaviour and response to therapy. The triple negative is a particular type of breast cancer defined by absence of oestrogen and progesterone receptor expression as well as absence of ERBB2 amplification. It is characterized by its biological aggressiveness, worse prognosis and lack of a therapeutic target in contrast with hormonal receptor positive and ERBB2+ breast cancers. Given these characteristics, triple-negative breast cancer is a challenge in today's clinical practice. A new breast cancer classification emerged recently in the scientific scene based in gene expression profiles. The new subgroups (luminal, ERBB2, normal breast and basal-like) have distinct gene expression patterns and phenotypical characteristics. Triple-negative breast cancer shares phenotypical features with basal-like breast cancer, which is in turn the most aggressive and with worse outcome. Since microarray gene-expression assays are only used in the research setting, clinicians use the triple-negative definition as a surrogate of basal-like breast cancer. The aim of this review, that focuses on triple-negative breast cancer, is to summarize the most relevant knowledge on this particular type of cancer in terms of molecular features, pathogenesis, clinical characteristics, current treatments and the new therapeutic options that include the use of platinum compounds, EGFR antagonists, antiangiogenics and PARP inhibitors. Advances in research are promising and new types of active drugs will become a reality in the near future, making possible a better outcome for this subgroup of breast cancer patients.