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Small-cell lung cancer (SCLC) is often associated with paraneoplastic syndromes. To assess the role of anti-neuronal autoantibodies (NAAs) as biomarkers of treatment outcome, we assessed NAAs in serial samples from SCLC patients treated with chemoimmunotherapy compared to chemotherapy alone. We evaluated 2 cohorts: in cohort 1 (C1), 47 patients received standard platinum/etoposide, and in cohort 2 (C2), 38 patients received ipilimumab, carboplatin and etoposide. Serum samples at baseline and subsequent time points were analyzed for the presence of NAAs. NAAs were detected at baseline in 25 patients (53.2%) in C1 and in 20 patients (52.6%) in C2 (most frequently anti-Sox1). NAA at baseline was associated with limited disease (75% vs 50%; p: 0.096) and better overall survival (15.1 m vs 11.7 m; p: 0.032) in C1. Thirteen patients (28.9%) showed 2 or more reactivities before treatment; this was associated with worse PFS (5.5 m vs 7.3 m; p: 0.005) in patients treated with chemoimmunotherapy. NAA titers decreased after therapy in 68.9% patients, with no differential patterns of change between cohorts. Patients whose NAA titer decreased after treatment, showed longer OS [18.5 m (95% CI: 15.8 – 21.2)] compared with those whose NAA increased [12.3 m (95% CI: 8.1 – 16.5; p 0.049)], suggesting that antibody levels correlate to tumor load. Our findings reinforce the role of NAAs as prognostic markers and tumor activity/burden in SCLC, warrant further investigation in their predictive role for immunotherapy and raise concern over the use of immunotherapy in patients with more than one anti-NAA reactivity.

Metastatic triple-negative breast cancer has a poor prognosis and poses significant therapeutic challenges. Until recently, limited therapeutic options have been available for patients with advanced disease after failure of first-line chemotherapy. The aim of this review is to assess the current evidence supporting second-line treatment options in patients with metastatic triple-negative breast cancer. Evidence was reviewed from controlled clinical trials in which eribulin, vinorelbine, capecitabine, gemcitabine, gemcitabine plus carboplatin, fam-trastuzumab-deruxtecan, sacituzumab govitecan, olaparib, and talazoparib were used in the second-line treatment for metastatic breast cancer, either as study drugs or as comparators. The benefit of treatment was evaluated using the European Society for Medical Oncology-Magnitude of Clinical Benefit Scale. Based on the evidence review, sacituzumab govitecan was identified as the preferred second-line treatment option for patients with metastatic triple-negative breast cancer, supported by clinical evidence and consensus across international clinical guidelines. Olaparib and talazoparib are of use in patients with human epidermal growth factor receptor 2-negative metastatic breast cancer and germline BRCA1/2 mutations. Exploratory data for fam-trastuzumab-deruxtecan suggest a survival benefit in human epidermal growth factor receptor 2-low, hormone-receptor-negative patients, but further solid evidence is required. Other chemotherapies with lower European Society for Medical Oncology-Magnitude of Clinical Benefit Scale scores may continue to be useful in highly selected patients., Competing Interests: Declarations. Authorship: All named authors meet the International Committee of Medical Journal Editors criteria for authorship for this article, take responsibility for the integrity of the work, and have given their approval for this version to be published. This article was prepared according to the International Society for Medical Publication Professionals’ Good Publication Practice for Communicating Company-Sponsored Medical Research: GPP3. Funding: This study was funded by Gilead Sciences. Conflicts of Interest: José Ángel García-Saenz has received consultant and/or speaker honoraria from Asofarma, AstraZeneca, Celgene, Daichii Sankyo, Eisai, Eli Lilly, Exact Sciences, Gilead, Jazz Pharmaceuticals, Menarini, MSD, Nolver (Adium), Novartis, Pfizer, Roche, Seagen, and Tecnofarma; research funding from AstraZeneca; and travel support from AstraZeneca, Daiichi Sankyo, and Gilead. Álvaro Rodríguez-Lescure has received consulting or advisory role fees from AstraZeneca, Daiichi-Sankyo, Eisai, Gilead, Eli Lilly, MSD, Novartis, Pfizer, Roche, and Seagen; research funding from Astellas, AstraZeneca, Bristol Myers Squibb, Eli Lilly, GEICAM, GILEAD, MSD, Novartis, Pfizer, Radius, Roche, and Zymeworks; and travel support from Novartis, Pfizer, and Roche. Josefina Cruz has received consultant and/or speaker honoraria from AstraZeneca, Daichii Sankyo, Deciphera, Eisai, Eli Lilly, Gilead, GlaxoSmithKline, Novartis, Pharmamar, Pierre Fabre, Roche, Seagen, and Pfizer, and travel support from AstraZeneca, Daiichi Sankyo, Gilead, Novartis, Pharmamar, and Roche. Joan Albanell has received consultant and/or speaker honoraria from Amgen, AstraZeneca, Daichii Sankyo, Eli Lilly, Gilead, Menarini, MSD, Pfizer, and Roche; research funding/grant support from Amgen, Daichii Sankyo, Eli Lilly, MSD, Pfizer, Novartis, and Roche; and travel support from Amgen, AstraZeneca, Daiichi Sankyo, Eli Lilly, MSD, Novartis, Pfizer, and Roche; and holds patents on LCOR and EGFR ECD (licensed), and stock options in Inbiomotion. Emilio Alba has received consultant and/or speaker honoraria from Exact Science, Gilead, Novartis, and Pfizer. Antonio Llombart has received consultant and/or speaker honoraria from AstraZeneca, Eli Lilly, MSD, Novartis, Pfizer, and Roche; research funding from Agendia, AstraZeneca, Eli Lilly, Gilead, MSD, Novartis, Pfizer, and Roche; and travel support from AstraZeneca, MSD, Pfizer, and Roche. Ethics Approval: Not applicable. Consent to Participate: Not applicable. Consent for Publication: Not applicable. Availability of Data and Material: Not applicable. Code Availability: Not applicable. Authors’ Contributions: JAGS, ARL, JC, JA, EA, and AL contributed equally to the conception, design, and writing of the manuscript. All approved the submitted version., (© 2025. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Immune checkpoint inhibitors (ICIs) targeting the programmed cell death protein 1 (PD-1)/programmed cell death 1 ligand 1 (PD-L1) pathway have transformed urothelial cancer (UC) therapy. The correlation between PD-L1 expression and ICI effectiveness is uncertain, leaving the role of PD-L1 as a predictive marker for ICI efficacy unclear. Among several ways to enhance the efficacy of ICI, trials are exploring combining ICIs with serine/threonine-protein kinase mTOR (mTOR) inhibitors in different tumor types. The potential interaction between mTOR inhibitors and PD-L1 expression in UC has not been well characterized. In our study, we investigated how phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway inhibitors (TAK-228, everolimus and TAK-117) affect PD-L1 expression and function in preclinical bladder cancer cell models. TAK-228 increased cell surface levels of glycosylated PD-L1 in all but one of the seven cell lines, regardless of baseline levels. TAK-228 promoted the secretion of epidermal growth factor (EGF) and interferon-β (IFNβ), both linked to PD-L1 protein induction. Blocking EGF and IFNβ receptors reversed the TAK-228-induced PD-L1 increase. Additionally, TAK-228 enhanced IFN-γ-induced PD-L1 expression and intracellular HLA-I levels in some cells. TAK-228-treated bladder cancer cells exhibited resistance to the cytotoxic effects of peripheral blood mononuclear cells (PBMCs) and cluster of differentiation 8 (CD8)+ T cells. The addition of an anti-PD-L1 antibody diminished this resistance in T24 cells. Increased expression of PD-L1 under TAK-228 exposure was confirmed in patient-derived explants (PDEs) treated ex vivo. These preclinical findings suggest that mTOR inhibition with TAK-228 can increase PD-L1 levels, potentially impacting the specific immune response against UC cells. This highlights the rationale for exploring the combination of mTOR inhibitors with ICIs in patients with advanced UC., (© 2024 The Author(s). Molecular Oncology published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

The most frequently used standard treatment for hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer patients consists of a CDK4/6 inhibitor (abemaciclib, ribociclib, or palbociclib) combined with endocrine therapy. Despite CDK4/6 inhibitors being part of routine care in the last few years, new adverse events continue to be reported. Here, we report two cases of palinopsia, a rare neurological visual disturbance that refers to the persistence or recurrence of a visual image after the removal of visual stimuli in patients treated with ribociclib and letrozole. Neuro-ophthalmological assessments and brain MRIs did not find any organic cause. However, palinopsia was related in a time- and dose-dependent manner to the intake of ribociclib. Following a one-level dose reduction of ribociclib, palinopsia was mild and well tolerated. Both patients continued the treatment with ribociclib, with one of them for almost 2 years. Based on the identification of two cases in our hospital in a short period of time, it is tempting to suggest that ribociclib-related palinopsias may not be uncommon. We propose that physicians should be aware of this ribociclib-associated adverse event. Patients presenting this symptom should undergo a routine workup (neuro-ophthalmological assessment and brain MRI) and, if negative, be reassured of its relation with ribociclib as well as the safety of continuing on this drug., Competing Interests: The authors declare that the research was conducted in absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Martos, Saint-Gerons, Masfarre, Castro-Henriques, Martinez-Garcia, Servitja and Albanell.)

Background: The capsule formulation of CDK4/6 inhibitor palbociclib has reduced solubility at gastric pH > 4.5 and may have decreased activity when used with proton-pump inhibitors (PPI). Herein, we report the effect of PPI on palbociclib capsule activity and safety in the PARSIFAL study., Methods: First-line endocrine-sensitive, hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) patients received palbociclib capsules plus fulvestrant or letrozole. The primary endpoint was progression-free survival (PFS). This post-hoc analysis compared PPI use. Patients were PPI-naïve (N-PPI) if not on PPI during the study, and either early (E-PPI) or long-term PPI (LT-PPI) if on PPI at study entry or for at least ≥⅔ of treatment, respectively. PPI groups were not mutually exclusive., Results: Among 486 patients, 66.9 % were N-PPI, 13.2 % E-PPI, 18.7 % LT-PPI, and 11.5 % of the PPI users were defined as neither. Median PFS (mPFS) was 29.6 months in the study population, 28.7 months in N-PPI, 23.0 months in E-PPI (Hazard Ratio [HR] 1.5; 95%Confidence Interval [CI] 1.1-2.2; p = 0.024), and 23.0 months in LT-PPI (HR 1.4; 95%CI 1.0-1.9; p = 0.035). By landmark analysis, PPI use was associated with poorer mPFS at 3 and 12 months. Grade ≥3 hematological adverse events occurred in 71.7 % of N-PPI, 57.8 % of E-PPI (p = 0.021), and 54.9 % of LT-PPI (p = 0.003). Dose reductions and dosing delays due to hematological toxicity occurred in 70.8 % of N-PPI, 56.3 % of E-PPI (p = 0.018), and 52.7 % of LT-PPI (p = 0.002)., Conclusions: PPI use may reduce palbociclib capsule toxicity, dose modifications, and clinical activity in HR+/HER2- ABC., Competing Interests: Declaration of competing interest SDC reports consulting for MEDSIR and IQVIA and honoraria from Pierre-Fabre, Novartis, and AstraZeneca. JMPG reports consulting for Roche, Eiasi, Daichii Sankyo, AstraZeneca, Gilead, MSD and Seagen and travel expenses from Roche. MB reports consulting fees from Pfizer, Novartis, Lilly, and Steamline-Menarini; honoraria from Pfizer, Novartis, and Lilly; and trave support from Pfizer. FD reports travel grants for Daichii, Novartis, and Pfizer, and participation in monitor/advisory boards for Daiichi, Seagen, Novartis, Gilead, Lilly, and MSD. MGG reports honoraria from Pfizer, Novartis, and AstraZeneca, travel grants from Lilly, Daiichi-Sankyo, and Pfizer, and participation in monitoring/advisory boards for AstraZeneca, Seagen, and Gilead. MRB reports honoraria from Pfizer, Novartis, AstraZenca, and Daiichi Sankyo. JG reports consulting fees from Novartis, Pfizer, AstraZeneca; honoraria from Novartis; and travel support from Roche and AstraZeneca. EAO reports consulting for AstraZeneca, Daichii, Gilead, MSD, and Seagen; honoraria from AstraZeneca, Daichii, Lilly, MSD, and Seagen; travel support from Daichii, Lilly, Gilead, and AstraZeneca; and participation in monitor/advisory boards for Gilead, AstraZeneca, Seagen, and Dachii. PS reports honoraria from Pfizer, AstraZeneca, Novartis, Roche, Merck, and Boehringer Ingelheim; a consulting role for Pfizer, AstraZeneca, Novartis, Roche, Merck, Boehringer Ingelheim, Bayer, Eisai, Celgene, and Puma; and institutional grants from Roche, Genentech, Oncogenex, and Novartis. FM reports grants from Roche, Novartis, AstraZeneca, GSK, MSD, Clovis, Vaccibody, Gilead Sciences, and Esai; consulting fees from AstraZeneca, GSK, and Roche; honoraria from AstraZeneca, MSD, Lilly, Pfizer, Novartis, GSK, Clovis, Myriad, Daiich Sankyo, Seagen, Pierre-Fabre, and Agendia; travel support from AstraZeneca, GSK, Pfizer, and Roche; and participation in advisory boards for Palleos and Amgen. JG reports grant/research support from Roche, Eiasi, and Exact Science; honoraria or consultation fees from AstraZeneca, Daiichi, Eisai, Exact Science, Evapharm, GE Healthcare, Gilead, Lilly, MSD, Novartis, Pfizer, Pierre Fabre, Roche, Seagen, Sothema and participation in company sponsored speaker's bureaus for Exact Science, Lilly, and Novartis. AS reports grants from Celgene, Roche, Abbvie; travel grants from Celgene, Roche, Pfizer, AstraZeneca, and honoraria from Roche, Celgene, Pfizer, AstraZeneca, Novartis, MSD, Tesaro, Lilly, Seagen, Gilead, GSK, Bayer, Amgen, Pierre Fabre. JA reports trial funding from MEDSIR and consulting for Pfizer, Lilly, and Novartis. PZ reports honoraria from Pfizer, Novartis, Roche, and Pierre Fabre; and travel support from Pfizer, Novartis, Roche, and Lilly. DW reports honoraria from Pfizer, Novartis, AstraZeneca and travel grants from Roche, and Novartis. JC reports consulting for Roche, Celgene, Cellestia, AstraZeneca, Seattle Genetics, Daiichi Sankyo, Erytech, Athenex, Polyphor, Lilly, Merck Sharp&Dohme, GSK, Leuko, Bioasis, Clovis Oncology, Boehringer Ingelheim, Ellipses, Hibercell, BioInvent, Gemoab, Gilead, Menarini, Zymeworks, Reveal Genomics, Expres2ion Biotechnologies; honoraria from Roche, Novartis, Celgene, Eisai, Pfizer, Samsung Bioepis, Lilly, Merck Sharp&Dohme, Daiichi Sankyo.; research funding to the Institution from Roche, Ariad pharmaceuticals, AstraZeneca, Baxalta GMBH/Servier Affaires, Bayer healthcare, Eisai, F. Hoffman-La Roche, Guardanth health, Merck Sharp&Dohme, Pfizer, Piqur Therapeutics, Puma C, Queen Mary University of London; stock shares for MEDSIR, Nektar Pharmaceuticals, Leuko (relative); Travel, accommodation, expenses from Roche, Novartis, Eisai, Pfizer, Daiichi Sankyo, Astrazeneca, Gilead; and Patents: Pharmaceutical Combinations of A Pi3k Inhibitor And A Microtubule Destabilizing Agent. Javier Cortés Castán, Alejandro Piris Giménez, Violeta Serra Elizalde. WO 2014/199294 A. ISSUED Her2 as a predictor of response to dual HER2 blockade in the absence of cytotoxic therapy. Aleix Prat, Antonio Llombart, Javier Cortés. US 2019/0338368 A1. LICENSED. ALC reports research support from Roche, Agendia, Lilly, Pfizer, Novartis, Merck Sharp & Dohme, Gilead, and Daichii-Sanyo; consulting for Lilly, Roche, Pfizer, and Novartis; participation in speakers' bureaus for Lilly, AstraZeneca, Merck Sharp & Dohme; travel support from Roche, Pfizer, AstraZeneca; and stock or other ownership in MEDSIR and Initia-Research. The remaining authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The variability in responses to neoadjuvant treatment with anti-HER2 antibodies prompts to personalized clinical management and the development of innovative treatment strategies. Tumor-infiltrating Natural Killer (TI-NK) cells can predict the efficacy of HER2-targeted antibodies independently from clinicopathological factors in primary HER2-positive breast cancer patients. Understanding the mechanism/s underlying this association would contribute to optimizing patient stratification and provide the rationale for combinatorial approaches with immunotherapy., Methods: We sought to uncover processes enriched in NK cell-infiltrated tumors as compared to NK cell-desert tumors by microarray analysis. Findings were validated in clinical trial-derived transcriptomic data. In vitro and in vivo preclinical models were used for mechanistic studies. Findings were analysed in clinical samples (tumor and serum) from breast cancer patients., Results: NK cell-infiltrated tumors were enriched in CCL5/IFNG-CXCL9/10 transcripts. In multivariate logistic regression analysis, IFNG levels underlie the association between TI-NK cells and pathological complete response to neoadjuvant treatment with trastuzumab. Mechanistically, the production of IFN-ɣ by CD16 +  NK cells triggered the secretion of CXCL9/10 from cancer cells. This effect was associated to tumor growth control and the conversion of CD16 into CD16 - CD103 +  NK cells in humanized in vivo models. In human breast tumors, the CD16 and CD103 markers identified lineage-related NK cell subpopulations capable of producing CCL5 and IFN-ɣ, which correlated with tissue-resident CD8 +  T cells. Finally, an early increase in serum CCL5/CXCL9 levels identified patients with NK cell-rich tumors showing good responses to anti-HER2 antibody-based neoadjuvant treatment., Conclusions: This study identifies specialized NK cell subsets as the source of IFN-ɣ influencing the clinical efficacy of anti-HER2 antibodies. It also reveals the potential of serum CCL5/CXCL9 as biomarkers for identifying patients with NK cell-rich tumors and favorable responses to anti-HER2 antibody-based neoadjuvant treatment., (© 2024. The Author(s).)

The combination of trastuzumab and pertuzumab as first-line therapy in patients with HER2-positive breast cancer has shown significant clinical benefits compared to trastuzumab alone. However, despite initial therapeutic success, most patients eventually progress, and tumors develop acquired resistance and invariably relapse. Therefore, there is an urgent need to improve our understanding of the mechanisms governing resistance in order to develop targeted therapeutic strategies with improved efficacy. We generated four novel HER2-positive cell lines via prolonged exposure to trastuzumab and pertuzumab and determined their resistance rates. Long-term resistance was confirmed by a significant increase in the colony-forming capacity of the derived cells. We authenticated the molecular identity of the new lines via both immunohistochemistry for the clinical phenotype and molecular profiling of point mutations. HER2 overexpression was confirmed in all resistant cell lines, and acquisition of resistance to trastuzumab and pertuzumab did not translate into differences in ER, PR, and HER2 receptor expression. In contrast, changes in the expression and activity of other HER family members, particularly HER4, were observed. In the same vein, analyses of the receptor and effector kinase status of different cellular pathways revealed that the MAPK pathway may be involved in the acquisition of resistance to trastuzumab and pertuzumab. Finally, proteomic analysis confirmed a significant change in the abundance patterns of more than 600 proteins with implications in key biological processes, such as ribosome formation, mitochondrial activity, and metabolism, which could be relevant mechanisms in the generation of resistance in HER2-positive breast cancer. We concluded that these resistant BCCLs may be a valuable tool to better understand the mechanisms of acquisition of resistance to trastuzumab and pertuzumab-based anti-HER2 therapy.

Stromal tumour infiltrating lymphocytes (sTIL) in haematoxylin and eosin (H&E) stained sections has been linked to better outcomes and better responses to neoadjuvant therapy in triple-negative and HER2-positive breast cancer (TNBC and HER2 +). However, the infiltrate includes different cell populations that have specific roles in the tumour immune microenvironment. Various studies have found high concordance between sTIL visual quantification and computational assessment, but specific data on the individual prognostic impact of plasma cells or lymphocytes within sTIL on patient prognosis is still unknown. In this study, we validated a deep-learning breast cancer sTIL scoring model (smsTIL) based on the segmentation of tumour cells, benign ductal cells, lymphocytes, plasma cells, necrosis, and 'other' cells in whole slide images (WSI). Focusing on HER2 + and TNBC patient samples, we assessed the concordance between sTIL visual scoring and the smsTIL in 130 WSI. Furthermore, we analysed 175 WSI to correlate smsTIL with clinical data and patient outcomes. We found a high correlation between sTIL values scored visually and semi-automatically (R = 0.76; P = 2.2e-16). Patients with higher smsTIL had better overall survival (OS) in TNBC (P = 0.0021). In the TNBC cohort, smsTIL was as an independent prognostic factor for OS. As part of this work, we introduce a new segmentation dataset of H&E-stained WSI., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Stromal tumor-infiltrating lymphocytes (sTILs) are a robust prognostic and predictive biomarker in triple-negative breast carcinoma. However, the sTIL compartment comprises different cell populations. The aim of the study is to characterize the distribution of T cells (CD3+ and CD8+), B cells, and plasma cells and explore their association with outcome in the surgical specimen of 62 patients. Furthermore, programmed death ligand 1 expression and the presence of tertiary lymphoid structures (TLSs) are explored. Patients with higher sTILs achieve better progression-free survival (PFS) (P = .0013), and tumors have more plasma cells in the infiltrate. Specifically, higher counts of T cells (both CD3+ and CD8+) have better PFS (P = .002 and P = .0086, respectively) as it is observed in tumors with higher infiltration of CD8+ T cells in the tumor core (P = .035). Higher infiltration by B cells and plasma cells shows a positive tendency toward increased PFS (P = .06 and P = .058). Programmed death ligand 1 (SP142) is positive in 56% of tumors. Tumors with at least 1 TLS (42%) show higher CD8+ T cell infiltration in the tumor core and the sTIL value doubles compared to tumors devoid of TLSs [sTIL mean: 36 ± 11% and 18 ± 5% (CI [Confidence Interval]: 95%), respectively]. Our study demonstrates that the characterization of the immune cell infiltration is as relevant as its distribution. Moreover, the importance of considering different immune cell types for classification is emphasized. Therefore, a new classification of triple-negative breast carcinoma immune infiltration with CD8+ T cell and plasma cell densities in the tumor core and infiltrative margin is proposed., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Gasdermin (GSDM)-mediated pyroptosis is functionally involved in multiple diseases, but Gasdermin-B (GSDMB) exhibit cell death-dependent and independent activities in several pathologies including cancer. When the GSDMB pore-forming N-terminal domain is released by Granzyme-A cleavage, it provokes cancer cell death, but uncleaved GSDMB promotes multiple pro-tumoral effects (invasion, metastasis, and drug resistance). To uncover the mechanisms of GSDMB pyroptosis, here we determined the GSDMB regions essential for cell death and described for the first time a differential role of the four translated GSDMB isoforms (GSDMB1-4, that differ in the alternative usage of exons 6-7) in this process. Accordingly, we here prove that exon 6 translation is essential for GSDMB mediated pyroptosis, and therefore, GSDMB isoforms lacking this exon (GSDMB1-2) cannot provoke cancer cell death. Consistently, in breast carcinomas the expression of GSDMB2, and not exon 6-containing variants (GSDMB3-4), associates with unfavourable clinical-pathological parameters. Mechanistically, we show that GSDMB N-terminal constructs containing exon-6 provoke cell membrane lysis and a concomitant mitochondrial damage. Moreover, we have identified specific residues within exon 6 and other regions of the N-terminal domain that are important for GSDMB-triggered cell death as well as for mitochondrial impairment. Additionally, we demonstrated that GSDMB cleavage by specific proteases (Granzyme-A, Neutrophil Elastase and caspases) have different effects on pyroptosis regulation. Thus, immunocyte-derived Granzyme-A can cleave all GSDMB isoforms, but in only those containing exon 6, this processing results in pyroptosis induction. By contrast, the cleavage of GSDMB isoforms by Neutrophil Elastase or caspases produces short N-terminal fragments with no cytotoxic activity, thus suggesting that these proteases act as inhibitory mechanisms of pyroptosis. Summarizing, our results have important implications for understanding the complex roles of GSDMB isoforms in cancer or other pathologies and for the future design of GSDMB-targeted therapies., (© 2023. The Author(s).)

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.

Objective: To assess the economic impact of introducing biosimilars of bevacizumab for the management of cancer patients receiving systemic bevacizumab in the National Health System (SNHS) of Spain., Methods: A 3-year budget impact analysis model was adapted to estimate the cost of introducing biosimilars of bevacizumab in the SNHS for the adult population who were candidates to receive treatment with bevacizumab. Values for the estimation of the population were obtained from the literature and were validated by an expert panel. In this analysis only pharmaceutical costs (€, year 2021) obtained from official databases were considered. A sensitivity analysis was performed to examine the robustness of the model., Results: The introduction of bevacizumab biosimilars would generate an annual cost saving of €11 558 268 (-5.1%) for the first year with a penetration share of biosimilars from 30.0%, €29 126 373 (-8.5%) for the second year with a share of 50.0% and €52 361 778 (-13.6%) for the third year with a share of 80.0%. The total pharmaceutical costs of the scenario without biosimilars are €227 033 352 for the first year, €342 663 209 for the second year and €385 013 076 for the third year. In contrast, the pharmaceutical costs of the scenario with bevacizumab biosimilars are €215 475 084, €313 536 836 and €332 651 297 for years 1, 2 and 3, respectively., Conclusions: The introduction of biosimilars in the Spanish Health System would generate saving costs in the pharmacological budget to boost biological drugs from the first year., Competing Interests: Competing interests: IO and LSO are employees of Pharmacoeconomics & Outcomes Research Iberia (PORIB), a consultant company specialising in health technology assessment, which has received financial support from Pfizer to conduct the development of the present work. JS is an employer of Pfizer Spain. MAC has received payment from Amgen, Roche and Samsung Bioepis for educational events and has participated in Advisory Boards for these companies. JA has received payment from Amgen, Roche and MSD and has received support for attending meetings for MSD and Amgen. EA has participated in Advisory Boards for Amgen, Bayer, Merck Serono, Roche and Sanofi. JGF has contracts with Biocartis, Bayer, Janssen, Merck Serono, Roche, Sanofi, Servier and Sysmex and has also received payment for lectures, presentations, speakers bureaus, manuscript writing or educational events, support for attending meetings and consulting fees from AstraZeneca, Biocartis, BMS, Bayer, Celgene, GSK, Janssen, Lilly, Merck Serono, MSD, Novartis, Pfizer, Foundation Medicine, Roche, Sanofi, Servier, Sysmex and tesaro. FR has received payment for lectures, presentations, speakers bureaus, manuscript writing or educational events and support for attending meetings from Amgen, Merck Serono, MSD, BMS, Servier, Roche, Sanofi and Lilly. MAC, JA, EA, JGF, AF and FR have received payment from Pfizer for consultant activities related to validation of the parameters and results. None of them received financial compensation for review and co-authorship of this manuscript. AF declares no conflicts of interest., (© European Association of Hospital Pharmacists 2023. Re-use permitted under CC BY-NC. No commercial re-use. Published by BMJ.)

Background: In the FLIPPER trial, palbociclib/fulvestrant significantly improved progression-free survival (PFS) compared with placebo/fulvestrant in postmenopausal women with HR+/HER2- advanced breast cancer (ABC)., Objective: We assessed health-related quality of life (QoL) using patient-reported outcomes (PROs)., Design and Methods: In this phase II double-blinded study, PROs were assessed at baseline after every three cycles and at the end of the treatment using the European Organisation for Research and Treatment of Cancer QLQ-C30 and QLQ-BR23. Time to deterioration (TTD) in global health status (GHS)/QoL was defined as a decrease of ⩾10 points. Changes from baseline (CFB) and TTD were analysed using linear mixed-effect and Cox regression models, respectively., Results: Of the 189 randomised (1:1) patients, 178 (94%) completed ⩾1 post-baseline assessment; 50% received ⩾22 cycles of study treatment, with a questionnaire compliance >90%. Mean baseline scores were comparable between arms. GHS/QoL scores were maintained throughout the palbociclib/fulvestrant treatment. CFB showed significant differences for GHS/QoL, appetite loss, constipation and systemic therapy side effect scores favouring placebo/fulvestrant. TTD in GHS/QoL was delayed in placebo/fulvestrant versus palbociclib/fulvestrant [30.3 versus 11.1 months; adjusted hazard ratio (aHR): 1.57, 95% CI: 1.03-2.39, p  = 0.036]; this difference was not significant in patients with progressive disease (aHR: 1.2, 95% CI: 0.6-2.2, p  = 0.658). No statistically significant differences in TTD were found for the other QLQ-C30 and QLQ-BR23 scales., Conclusions: Although TTD in GHS/QoL was prolonged with placebo/fulvestrant, no differences were observed on other functional or symptom scales. This finding and the improvement in PFS support the combination of palbociclib/fulvestrant as a beneficial therapeutic option for HR+/HER2- ABC., Trial Registration Number: Sponsor Study Code: GEICAM/2014-12EudraCT Number: 2015-002437-21ClinTrials.gov reference: NCT02690480., Competing Interests: Dr. Tibau has received speaker fees from Novartis and Eisai. Dr. Ramos has received speaker’s bureau from Novartis, Pfizer and Roche Farma. Dr. de La Cruz-Merino has received advisory board fees from MSD-Merk, Roche Farma, Bristol-Myers-Squibb, Pierre-Fabré, Amgen and Novartis; research funding from MSD-Merck, Roche Farma, Celgene; speaking fees from MSD-Merck, Roche Farma, Bristol-Myers-Squibb and Amgen; grant support from Bristol-Myers-Squibb and Roche Farma. Dr. Santaballa has received consulting or advisory role fees from GSK, Clovis, MSD, AstraZeneca, Roche and Pfizer; speakers’ honoraria from GSK, Clovis, Roche, MSD, AstraZeneca and Pfizer; and grant support by Pfizer, GSK and MSD. Dr. Martínez-Jañez has received advisory board fees from Roche Farma, Astra Zeneca, Pfizer, Novartis, Lilly, Daiichi Sankyo, Agendia and Eisai. Dr. Moreno has received advisory board fees from Roche/Genentech, Novartis, Pfizer, AstraZeneca, MSD-Merck and Daiichi Sankyo/AstraZeneca; speaker’s bureau fees from Pfizer; travel accommodations expenses from Roche/Genentech, Pfizer, Novartis, Daiichi Sankyo/Astra Zeneca. Dr. Fernández has received consultant or advisory fees from MSD-Astra Zeneca; speaker’s bureau fees from Pfizer, AstraZeneca, Roche, MSD, Clovis and GSK. Dr. Alarcón: has received honoraria from GSC, Clovis, Roche and AstraZeneca; consulting or advisory board honoraria from GSK and Clovis; speaker and expert testimony fees from GSK, Clovis and Roche; and travel and accommodation support from GSK. Dr. de La Haba-Rodríguez has received speaker’s honoraria from AstraZeneca, Pfizer, Novartis and Lilly. Dr. Sánchez-Rovira has received honoraria from Novartis, Lilly, Pfizer, Roche and Seagen. Dr. Bueno Muiño has received speaker fees from Novartis, Lilly, AstraZeneca, BMS, Pfizer and GSK. Dr. Albanell has received consulting or advisory role fees from Roche, Pfizer, Amgen, MSD, Lilly and Daiichi-Sankyo; research funding or grant support trials by Roche, Pfizer, Amgen, MSD, Lilly, Daiichi-Sankyo; and travel and accommodation support from Roche, Pfizer, Amgen, MSD, Lilly and Daiichi-Sankyo. All remaining authors have declared no conflicts of interest. GEICAM has received research funding from Roche/Genentech, Bristol-Myers Squibb, Novartis, Pfizer, Celgene, AstraZeneca, Merck Sharp & Dohme, Pierre Fabre and Takeda. A complete list of the FLIPPER trial collaborators is provided in the Supplemental Appendix., (© The Author(s), 2023.)

Background: Palbociclib has gained a central role in the treatment of hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC). Despite its manageable toxicity profile, venous thromboembolism (VTE) or interstitial lung disease (ILD)/pneumonitis may infrequently occur. Therefore, we provide a comprehensive summary of the safety and tolerability of the combination of endocrine therapy and palbociclib among patients included in the randomized phase 2 PARSIFAL study., Materials and Methods: Patients with endocrine-sensitive HR+/HER2- ABC and no prior therapy in an advanced setting (n = 486) were randomly assigned 1:1 to receive fulvestrant-palbociclib (FP) or letrozole-palbociclib (LP). Laboratory tests and the incidence of adverse events (AEs) were recorded at baseline and day 1 of each cycle. Progression-free survival (PFS) was estimated for patients with and without VTE., Results: A total of 483 patients were analyzed. Neutropenia, leukopenia, anemia, asthenia, arthralgia, fatigue, and diarrhea were the most frequent AEs in both groups. Febrile neutropenia occurred in 3 (1.2%) patients of the FP group and in 1 (0.4%) patient in the LP group. Six (2.5%; 0.4% grade 3) patients in the FP group and 6 patients (2.5%; 0.4% grade 3) in the LP group experienced ILD/pneumonitis. Pulmonary embolism was reported in 12 (5.0%) patients in the FP group and 6 (2.5%) patients in the LP group. Advanced age at baseline was the only factor significantly associated with an increased risk of pulmonary embolism (P < .01)., Conclusion: The PARSIFAL data confirmed the favorable safety profile of both palbociclib regimens. VTE and ILD/pneumonitis were occasionally reported, and their early detection allowed patients to continue treatment effectively without detriment to efficacy., Clinicaltrials.gov Identifier: NCT02491983; https://clinicaltrials.gov/ct2/show/NCT02491983)., (© The Author(s) 2022. Published by Oxford University Press.)

Purpose: To assess the efficacy and exploratory biomarkers of continuing palbociclib plus endocrine therapy (ET) beyond progression on prior palbociclib-based regimen in patients with hormone receptor-positive/HER2-negative (HR+/HER2-) advanced breast cancer (ABC)., Patients and Methods: The multicenter, open-label, phase II BioPER trial included women who had experienced a progressive disease (PD) after having achieved clinical benefit on the immediately prior palbociclib plus ET regimen. Palbociclib (125 mg, 100 mg, or 75 mg daily orally for 3 weeks and 1 week off as per prior palbociclib-based regimen) plus ET of physician's choice were administered in 4-week cycles until PD or unacceptable toxicity. Coprimary endpoints were clinical benefit rate (CBR) and percentage of tumors with baseline loss of retinoblastoma (Rb) protein expression. Additional endpoints included safety and biomarker analysis., Results: Among 33 patients enrolled, CBR was 34.4% [95% confidence interval (CI), 18.6-53.2; P < 0.001] and 13.0% of tumors (95% CI, 5.2-27.5) showed loss of Rb protein expression, meeting both coprimary endpoints. Median progression-free survival was 2.6 months (95% CI, 1.8-6.7). No new safety signals were reported. A signature that included baseline mediators of therapeutic resistance to palbociclib and ET (low Rb score, high cyclin E1 score, ESR1 mutation) was independently associated with shorter median progression-free survival (HR, 22.0; 95% CI, 1.71-282.9; P = 0.018)., Conclusions: Maintaining palbociclib after progression on prior palbociclib-based regimen seems to be a reasonable, investigational approach for selected patients. A composite biomarker signature predicts a subset of patients who may not derive a greater benefit from palbociclib rechallenge, warranting further validation in larger randomized controlled trials., (©2022 The Authors; Published by the American Association for Cancer Research.)

Treatment for the HER2+ breast cancer subtype is still unsatisfactory, despite breakthroughs in research. The discovery of various new molecular mechanisms of transcription factors may help to make treatment regimens more effective. The transcription factor SALL4 has been related to aggressiveness and resistance therapy in cancer. Its molecular mechanisms and involvement in various signaling pathways are unknown in the HER2+ breast cancer subtype. In this study, we have evaluated the implication of SALL4 in the HER2+ subtype through its expression in patients' samples and gain and loss of function in HER2+ cell lines. We found higher SALL4 expression in breast cancer tissues compared to healthy tissue. Interestingly, high SALL4 expression was associated with disease relapse and poor patient survival. In HER2+ cell lines, transient overexpression of SALL4 modulates PI3K/AKT signaling through regulating PTEN expression and BCL2, which increases cell survival and proliferation while reducing the efficacy of trastuzumab. SALL4 has also been observed to regulate the epithelial-mesenchymal transition and stemness features. SALL4 overexpression significantly reduced the epithelial markers E-cadherin, while it increased the mesenchymal markers β-catenin, vimentin and fibronectin. Furthermore, it has been also observed an increased expression of MYC, an essential transcription factor for regulating epithelial-mesenchymal transition and/or cancer stem cells. Our study demonstrates, for the first time, the importance of SALL4 in the HER2+ subtype and partial regulation of trastuzumab sensitivity. It provides a viable molecular mechanism-driven therapeutic strategy for an important subset of HER2-overexpressing patients whose malignancies are mediated by SALL4 expression.

About 50% of human epidermal growth factor receptor 2 (HER2)+ breast cancer patients do not benefit from HER2-targeted therapy and almost 20% of them relapse after treatment. Here, we conduct a detailed analysis of two independent cohorts of HER2+ breast cancer patients treated with trastuzumab to elucidate the mechanisms of resistance to anti-HER2 monoclonal antibodies. In addition, we develop a fully humanized immunocompetent model of HER2+ breast cancer recapitulating ex vivo the biological processes that associate with patients' response to treatment. Thanks to these two approaches, we uncover a population of TGF-beta-activated cancer-associated fibroblasts (CAF) specific from tumors resistant to therapy. The presence of this cellular subset related to previously described myofibroblastic (CAF-S1) and podoplanin+ CAF subtypes in breast cancer associates with low IL2 activity. Correspondingly, we find that stroma-targeted stimulation of IL2 pathway in unresponsive tumors restores trastuzumab anti-cancer efficiency. Overall, our study underscores the therapeutic potential of exploiting the tumor microenvironment to identify and overcome mechanisms of resistance to anti-cancer treatment., (© 2022. The Author(s).)

Background: A cancer diagnosis is a source of psychological and emotional stress, which are often maintained for sustained periods of time that may lead to depressive disorders. Depression is one of the most common psychological conditions in patients with cancer. According to the Global Cancer Observatory, breast and colorectal cancers are the most prevalent cancers in both sexes and across all age groups in Spain., Objective: This study aimed to compare the prevalence of depression in patients before and after the diagnosis of breast or colorectal cancer, as well as to assess the usefulness of the analysis of free-text clinical notes in 2 languages (Spanish or Catalan) for detecting depression in combination with encoded diagnoses., Methods: We carried out an analysis of the electronic health records from a general hospital by considering the different sources of clinical information related to depression in patients with breast and colorectal cancer. This analysis included ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification) diagnosis codes and unstructured information extracted by mining free-text clinical notes via natural language processing tools based on Systematized Nomenclature of Medicine Clinical Terms that mentions symptoms and drugs used for the treatment of depression., Results: We observed that the percentage of patients diagnosed with depressive disorders significantly increased after cancer diagnosis in the 2 types of cancer considered-breast and colorectal cancers. We managed to identify a higher number of patients with depression by mining free-text clinical notes than the group selected exclusively on ICD-9-CM codes, increasing the number of patients diagnosed with depression by 34.8% (441/1269). In addition, the number of patients with depression who received chemotherapy was higher than those who did not receive this treatment, with significant differences (P<.001)., Conclusions: This study provides new clinical evidence of the depression-cancer comorbidity and supports the use of natural language processing for extracting and analyzing free-text clinical notes from electronic health records, contributing to the identification of additional clinical data that complements those provided by coded data to improve the management of these patients., (©Angela Leis, David Casadevall, Joan Albanell, Margarita Posso, Francesc Macià, Xavier Castells, Juan Manuel Ramírez-Anguita, Jordi Martínez Roldán, Laura I Furlong, Ferran Sanz, Francesco Ronzano, Miguel A Mayer. Originally published in JMIR Cancer (https://cancer.jmir.org), 11.07.2022.)

In patients with trastuzumab-resistant HER2-positive breast cancer, the combination of everolimus (mTORC1 inhibitor) with trastuzumab failed to show a clinically significant benefit. However, the combination of mTOR inhibition and the antibody-drug conjugate (ADC) trastuzumab-emtansine (T-DM1) remains unexplored. We tested T-DM1 plus everolimus in a broad panel of HER2-positive breast cancer cell lines. The combination was superior to T-DM1 alone in four cell lines (HCC1954, SKBR3, EFM192A, and MDA-MB-36) and in two cultures from primary tumor cells derived from HER2-positive patient-derived xenografts (PDX), but not in BT474 cells. In the trastuzumab-resistant HCC1954 cell line, we characterized the effects of the combination using TAK-228 (mTORC1 and -2 inhibitor) and knockdown of the different mTOR complex components. T-DM1 did not affect mTOR downstream signaling nor induct autophagy. Importantly, mTOR inhibition increased intracellular T-DM1 levels, leading to increased lysosomal accumulation of the compound. The increased efficacy of mTOR inhibition plus T-DM1 was abrogated by lysosome inhibitors (chloroquine and bafilomycin A1). Our experiments suggest that BT474 are less sensitive to T-DM1 due to lack of optimal lysosomal processing and intrinsic resistance to the DM1 moiety. Finally, we performed several in vivo experiments that corroborated the superior activity of T-DM1 and everolimus in HCC1954 and PDX-derived mouse models. In summary, everolimus in combination with T-DM1 showed strong antitumor effects in HER2-positive breast cancer, both in vitro and in vivo. This effect might be related, at least partially, to mTOR-dependent lysosomal processing of T-DM1, a finding that might apply to other ADCs that require lysosomal processing., Implications: Inhibition of mTOR increases the antitumor activity of T-DM1, supporting that the combination of mTOR inhibitors and antibody-drug conjugates warrants clinical evaluation in patients with HER2-positive breast cancer., (©2022 American Association for Cancer Research.)

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.

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.

Ligand-dependent corepressor (LCOR) mediates normal and malignant breast stem cell differentiation. Cancer stem cells (CSCs) generate phenotypic heterogeneity and drive therapy resistance, yet their role in immunotherapy is poorly understood. Here we show that immune-checkpoint blockade (ICB) therapy selects for LCOR low CSCs with reduced antigen processing/presentation machinery (APM) driving immune escape and ICB resistance in triple-negative breast cancer (TNBC). We unveil an unexpected function of LCOR as a master transcriptional activator of APM genes binding to IFN-stimulated response elements (ISREs) in an IFN signaling-independent manner. Through genetic modification of LCOR expression, we demonstrate its central role in modulation of tumor immunogenicity and ICB responsiveness. In TNBC, LCOR associates with ICB clinical response. Importantly, extracellular vesicle (EV) Lcor-messenger RNA therapy in combination with anti-PD-L1 overcame resistance and eradicated breast cancer metastasis in preclinical models. Collectively, these data support LCOR as a promising target for enhancement of ICB efficacy in TNBC, by boosting of tumor APM independently of IFN., (© 2022. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Background: Derived neutrophil-to-lymphocyte ratio (dNLR) is a biomarker associated with clinical outcome in breast cancer (BC). We analyzed the association of dNLR with pathological complete response (pCR) in triple-negative BC (TNBC) patients receiving neoadjuvant chemotherapy (CT)., Methods: This is a retrospective analysis of two randomized studies involving early stage/locally advanced TNBC patients receiving anthracycline/taxane-based CT+/-carboplatin (GEICAM/2006-03) or nab-paclitaxel/paclitaxel followed by anthracycline regimen (ETNA). dNLR was calculated as the ratio of neutrophils to the difference between total leukocytes and neutrophils in peripheral blood before CT (baseline) and at the end of treatment (EOT). Logistic regression analyses were used to explore dNLR association with pCR., Results: In total, 308 TNBC patients were analyzed, 216 from ETNA and 92 from GEICAM/2006-03. Baseline median dNLR was 1.61 (interquartile range (IQR): 1.25-2.04) and at EOT 1.53 (IQR: 0.96-2.22). Baseline dNLR showed positive correlation with increased tumor size ( p -value = 1e-04). High baseline dNLR, as continuous variable or using median cutoff, was associated with lower likelihood of pCR in univariate analysis. High EOT dNLR as continuous variable or using quartiles was also associated with lower pCR rate in uni- and multivariate analyses., Conclusions: High baseline and EOT dNLR correlates with lower benefit from neoadjuvant CT in TNBC., Competing Interests: AO is currently an employee of Symphogen, Denmark. MM has received honoraria from Pierre Fabre and support for attending meetings and/or travel from Eisai, Novartis, Pfizer, Pierre Fabre, and Roche. He has received advisory board honoraria from Amgen, Astra Zeneca, Eli Lilly, Gentili, MSD Italia, Novartis, Pfizer, and Roche. JA has received advisory board honoraria from Roche, Lilly, Merck, Daiichi-Sankyo/Astrazeneca, and Seagen and a speaker’s honoraria from Pfizer. GBia has received honoraria from Pfizer, Roche, AstraZeneca, Lilly, Novartis, Noepharm Israel, Amgen, MSD, Chugai, Sanofi, Daiichi Sankyo, Eisai, Gilead, Seagen, and Exact Science. EA has received advisory board honoraria from Roche, Novartis, Pfizer, Lilly, BMS, Genomic Health, and Nanostring and support for attending meetings and/or travel from Celgene, as well as investigation grants from Roche, Pfizer, Sysmex, MSD, and Nanostring. LG has received advisory board honoraria from ADC Therapeutics, AstraZeneca, Celgene, Eli Lilly, G1 Therapeutics, Genentech, Genomic Health, Merck Sharp & Dohme, Oncolytics Biotech, Odonate Therapeutics, Onkaido Therapeutics, Roche, Pfizer, Taiho Pharmaceutical, Hexal Sandoz, Seattle Genetics, Synthon, Zymeworks, and Sanofi-Aventis; consultant honoraria for selected programs of Forty Seven (CD47), GENENTA, METIS Precision Medicine, Novartis, Odonate Therapeutics, Revolution Medicines, Synaffix, Zymeworks, Menarini Ricerche, Amgen, and Biomedical Insights; and research support from Zymeworks, Revolution Medicines (his institution). LG is coinventor of “European Patent Application N.12195182.6 and 12196177.5,” titled “PDL-1 expression in anti-HER2 therapy”—Roche (no compensation provided). The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ocaña, Chacón, Calvo, Antón, Mansutti, Albanell, Martínez, Lahuerta, Bisagni, Bermejo, Semiglazov, Thill, Chan, Morales, Herranz, Tusquets, Chiesa, Caballero, Valagussa, Bianchini, Alba and Gianni.)

Background: The potential benefit of adding palbociclib to fulvestrant as first-line treatment in hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative endocrine-sensitive advanced breast cancer (ABC) patients remains uncharacterized., Patients and Methods: In this randomized (1:1), double-blind, phase II study, postmenopausal women with HR-positive, HER2-negative ABC with de novo metastatic disease or those who relapsed after >12 months of adjuvant endocrine therapy received palbociclib/fulvestrant or placebo/fulvestrant. Stratification was based on recurrent versus de novo metastatic disease and visceral involvement. The primary objective was one-year progression-free survival (PFS-1y) rate. The sample size was 190 patients. The two-sided alpha of 0.2, 80% of power to detect a difference between the arms, assuming PFS rates of 0.695 and 0.545 for palbociclib/fulvestrant and placebo/fulvestrant, respectively., Results: In total, 189 patients were randomized to palbociclib/fulvestrant ([n = 94] or placebo/fulvestrant [n = 95]). 45.5% and 60.3% of patients had de novo metastatic disease and visceral involvement, respectively. PFS-1y rates were 83.5% and 71.9% in the palbociclib/fulvestrant and placebo/fulvestrant arms, (HR 0.55, 80% CI 0.36-0.83, P = 0.064). The median PFS were 31.8 and 22.0 months for the palbociclib/fulvestrant and placebo/fulvestrant arms (aHR 0.48, 80% CI 0.37-0.64, P = 0.001). The most frequent grade 3-4 adverse events were neutropenia (68.1% vs. 0%), leucopenia (26.6% vs. 0%), anemia (3.2% vs. 0%), and lymphopenia (14.9% vs. 2.1%) for the palbociclib/fulvestrant and placebo/fulvestrant, respectively. The most frequent non-hematologic grade 3-4 adverse event was fatigue (4.3% vs. 0%)., Conclusions: Palbociclib/fulvestrant demonstrated better PFS-1y rates and median PFS than placebo/fulvestrant in HR-positive/HER2-negative endocrine-sensitive ABC patients., Competing Interests: Conflict of interest statement Joan Albanell has received consulting or advisory role fees from Roche, Pfizer, Amgen, MSD, Lilly and Daiichi-Sankyo; research funding or grant support trials by Roche, Pfizer, Amgen, MSD, Lilly, Daiichi-Sankyo; and travel and accommodation support from Roche, Pfizer, Amgen, MSD, Lilly and Daiichi-Sankyo. Manuel Ramos has received honoraria from Novartis, Roche, and Pfizer. Luis de la Cruz-Merino has received consulting or advisory role fees from MSD-Merck, Roche Farma, Bristol-Myers-Squibb, Pierre-Fabré, Amgen and Novartis; research funding from MSD-Merck, Roche Farma and Celgene; speaker's honoraria from MSD-Merck, Roche-Farma, Bristol-Myers-Squibb and Amgen; and grant support by Roche Farma and Bristol-Myers-Squibb. Ana Santaballa has received consulting or advisory role fees from GSK, Clovis, MSD, AstraZeneca, Roche and Pfizer; speakers' honoraria from GSK, Clovis, Roche, MSD, AstraZeneca and Pfizer; and grant support by Pfizer, GSK and MSD. Noelia Martinez-Janez has received advisory board honorary from Roche, AstraZeneca, Daichi, Pfizer, Novartis, Lilly and Eisai. Fernando Moreno has received consulting or advisory fees from Roche/Genentech, Novartis, Pfizer, AstraZeneca, and MSD; speakers' honoraria from Pfizer and Roche/Genentech; research funding fees from Pfizer; travel and accommodation support from Roche/Genentech, Pfizer and Novartis. Isaura Fernández has received consulting or advisory role fees from AstraZeneca, MSD, GlaxoSmithKline and Roche; research funding from Roche; and speaker's honoraria from Clovis, Pfizer and Novartis. Jesús Alarcón has received honoraria by GSC, Clovis, Roche and AstraZeneca; consulting or advisory board honoraria by GSK and Clovis; speaker and expert testimony fees by GSK, Clovis and Roche; and travel and accommodation support from GSK. Juan de la Haba has received speaker's honoraria from AstraZeneca, Pfizer, Novartis and Lilly. Mireia Margelí has received advisory board fees from Roche, Novartis, Pfizer, and Eisai. Her institution, ICO -Badalona. B-ARGO (Badalona Applied Research Group in Oncology) Hospital Universitari Germans Trias i Pujol, Badalona, has received funding research from Roche, Pfizer, Novartis, Lilly, AstraZeneca, Eisai, and Kern. Antonio Antón has received advisory board fees from Bayer, Spain. Federico Rojo has received consulting or advisory role fees from Roche, Pfizer, Novartis, BMS, Pierre-Fabre, Incyte, Abbvie, Amgen, MSD, and Lilly; and travel and accommodation support from Roche. GEICAM has received research funding from Roche/Genentech, Bristol-Myers Squibb, Novartis, Pfizer, Celgene, AstraZeneca, Merck Sharp & Dohme, Pierre Fabre, and Takeda. All remaining authors have declared no conflicts of interest., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The combination of trastuzumab plus pertuzumab plus docetaxel as a first-line therapy in patients with HER2-positive metastatic breast cancer has provided significant clinical benefits compared to trastuzumab plus docetaxel alone. However, despite the therapeutic success of existing therapies targeting HER2, tumours invariably relapse. Therefore, there is an urgent need to improve our understanding of the mechanisms governing resistance, so that specific therapeutic strategies can be developed to provide improved efficacy. It is well known that the tumour microenvironment (TME) has a significant impact on cancer behaviour. Cancer-associated fibroblasts (CAFs) are essential components of the tumour stroma that have been linked to acquired therapeutic resistance and poor prognosis in breast cancer. For this reason, it would be of interest to identify novel biomarkers in the tumour stroma that could emerge as therapeutic targets for the modulation of resistant phenotypes. Conditioned medium experiments carried out in our laboratory with CAFs derived from HER2-positive patients showed a significant capacity to promote resistance to trastuzumab plus pertuzumab therapies in two HER2-positive breast cancer cell lines (BCCLs), even in the presence of docetaxel. In order to elucidate the components of the CAF-conditioned medium that may be relevant in the promotion of BCCL resistance, we implemented a multiomics strategy to identify cytokines, transcription factors, kinases and miRNAs in the secretome that have specific targets in cancer cells. The combination of cytokine arrays, label-free LC-MS/MS quantification and miRNA analysis to explore the secretome of CAFs under treatment conditions revealed several up- and downregulated candidates. We discuss the potential role of some of the most interesting candidates in generating resistance in HER2-positive breast cancer.

Enhancing natural killer (NK) cell-based cancer immunotherapy by overcoming immunosuppression is an area of intensive research. Here, we have demonstrated that the anti-CD137 agonist urelumab can overcome TGFβ-mediated inhibition of human NK-cell proliferation and antitumor function. Transcriptomic, immunophenotypic, and functional analyses showed that CD137 costimulation modified the transcriptional program induced by TGFβ on human NK cells by rescuing their proliferation in response to IL2, preserving their expression of activating receptors (NKG2D) and effector molecules (granzyme B, IFNγ) while allowing the acquisition of tumor-homing/retention features (CXCR3, CD103). Activated NK cells cultured in the presence of TGFβ1 and CD137 agonist recovered CCL5 and IFNγ secretion and showed enhanced direct and antibody-dependent cytotoxicity upon restimulation with cancer cells. Trastuzumab treatment of fresh breast carcinoma-derived multicellular cultures induced CD137 expression on tumor-infiltrating CD16 + NK cells, enabling the action of urelumab, which fostered tumor-infiltrating NK cells and recapitulated the enhancement of CCL5 and IFNγ production. Bioinformatic analysis pointed to IFNG as the driver of the association between NK cells and clinical response to trastuzumab in patients with HER2-positive primary breast cancer, highlighting the translational relevance of the CD137 costimulatory axis for enhancing IFNγ production. Our data reveals CD137 as a targetable checkpoint for overturning TGFβ constraints on NK-cell antitumor responses., (©2021 American Association for Cancer Research.)

Importance: The cyclin-dependent kinase 4 and 6 inhibitor palbociclib in combination with letrozole has become a standard first-line treatment for patients with endocrine-sensitive, hormone receptor-positive, ERBB2-negative advanced breast cancer. Meanwhile, the antiestrogen fulvestrant was shown to be superior to anastrozole in the absence of cyclin-dependent kinase 4 and 6 inhibition for this patient population., Objective: To assess whether fulvestrant is superior to letrozole when combined with palbociclib in the first-line scenario., Design, Setting, and Participants: In this international, randomized, open-label, phase 2 clinical study conducted from July 30, 2015, to January 8, 2018, patients with hormone receptor-positive, ERBB2-negative advanced breast cancer with no prior therapy in the metastatic setting and endocrine-sensitive criteria were recruited from 47 centers in 7 countries. Data were analyzed from February 11 to May 15, 2020., Interventions: Patients were randomly assigned (1:1 ratio) to receive palbociclib with either fulvestrant or letrozole. Stratification factors were type of disease presentation (de novo vs recurrent) and the presence of visceral involvement (yes vs no)., Main Outcomes and Measures: The primary end point was investigator-assessed progression-free survival determined by Response Evaluation Criteria in Solid Tumors, version 1.1., Results: A total of 486 women (median age, 63 years [range, 25-90 years]; 3 Asian women [0.6%]; 4 Black women [0.8%]; 461 White women [94.9%]; 18 women of unknown race [3.7%]) were randomized (243 to fulvestrant-palbociclib and 243 to letrozole-palbociclib). Median investigator-assessed progression-free survival was 27.9 months (95% CI, 24.2-33.1 months) in the fulvestrant-palbociclib group vs 32.8 months (95% CI, 25.8-35.9 months) in the letrozole-palbociclib group (hazard ratio, 1.13; 95% CI, 0.89-1.45; P = .32). This result was consistent across the stratification factors. No significant differences were observed in objective response rate (46.5% vs 50.2%) and 3-year overall survival rate (79.4% vs 77.1%) for fulvestrant-palbociclib and letrozole-palbociclib, respectively. Grade 3-4 adverse events were comparable among treatment groups, and no new safety signals were identified. No treatment-related deaths were reported., Conclusions and Relevance: Although fulvestrant-palbociclib demonstrated significant antitumor activity, this randomized clinical trial failed to identify an improvement in progression-free survival with this regimen over letrozole-palbociclib in patients with endocrine-sensitive, hormone receptor-positive, ERBB2-negative advanced breast cancer., Trial Registration: ClinicalTrials.gov Identifier: NCT02491983.

Older children and teenagers with bilateral cochlear implants often have poor spatial hearing because they cannot fuse sounds from the two ears. This deficit jeopardizes speech and language development, education, and social well-being. The lack of protocols for fitting bilateral cochlear implants and resources for spatial-hearing training contribute to these difficulties. Spatial hearing develops with bilateral experience. A large body of research demonstrates that sound localisation can improve with training, underpinned by plasticity-driven changes in the auditory pathways. Generalizing training to non-trained auditory skills is best achieved by using a multi-modal (audio-visual) implementation and multi-domain training tasks (localisation, speech-in-noise, and spatial music). The goal of this work was to develop a package of virtual-reality games (BEARS, Both EARS) to train spatial hearing in young people (8-16 years) with bilateral cochlear implants using an action-research protocol. The action research protocol used formalized cycles for participants to trial aspects of the BEARS suite, reflect on their experiences, and in turn inform changes in the game implementations. This participatory design used the stakeholder participants as co-creators. The cycles for each of the three domains (localisation, spatial speech-in-noise, and spatial music) were customized to focus on the elements that the stakeholder participants considered important. The participants agreed that the final games were appropriate and ready to be used by patients. The main areas of modification were: the variety of immersive scenarios to cover age range and interests, the number of levels of complexity to ensure small improvements were measurable, feedback, and reward schemes to ensure positive reinforcement, and an additional implementation on an iPad for those who had difficulties with the headsets due to age or balance issues. The effectiveness of the BEARS training suite will be evaluated in a large-scale clinical trial to determine if using the games lead to improvements in speech-in-noise, quality of life, perceived benefit, and cost utility. Such interventions allow patients to take control of their own management reducing the reliance on outpatient-based rehabilitation. For young people, a virtual-reality implementation is more engaging than traditional rehabilitation methods, and the participatory design used here has ensured that the BEARS games are relevant., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Vickers, Salorio-Corbetto, Driver, Rocca, Levtov, Sum, Parmar, Dritsakis, Albanell Flores, Jiang, Mahon, Early, Van Zalk and Picinali.)

AURORA aims to study the processes of relapse in metastatic breast cancer (MBC) by performing multi-omics profiling on paired primary tumors and early-course metastases. Among 381 patients (primary tumor and metastasis pairs: 252 targeted gene sequencing, 152 RNA sequencing, 67 single nucleotide polymorphism arrays), we found a driver role for GATA1 and MEN1 somatic mutations. Metastases were enriched in ESR1, PTEN, CDH1, PIK3CA , and RB1 mutations; MDM4 and MYC amplifications; and ARID1A deletions. An increase in clonality was observed in driver genes such as ERBB2 and RB1 . Intrinsic subtype switching occurred in 36% of cases. Luminal A/B to HER2-enriched switching was associated with TP53 and/or PIK3CA mutations. Metastases had lower immune score and increased immune-permissive cells. High tumor mutational burden correlated to shorter time to relapse in HR + /HER2 - cancers. ESCAT tier I/II alterations were detected in 51% of patients and matched therapy was used in 7%. Integration of multi-omics analyses in clinical practice could affect treatment strategies in MBC. SIGNIFICANCE: The AURORA program, through the genomic and transcriptomic analyses of matched primary and metastatic samples from 381 patients with breast cancer, coupled with prospectively collected clinical data, identified genomic alterations enriched in metastases and prognostic biomarkers. ESCAT tier I/II alterations were detected in more than half of the patients. This article is highlighted in the In This Issue feature, p. 2659 ., (©2021 The Authors; Published by the American Association for Cancer Research.)

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., (©2021 American Association for Cancer Research.)

The use of anti-HER2 therapies has significantly improved clinical outcome in patients with HER2-positive breast cancer, yet a substantial proportion of patients acquire resistance after a period of treatment. The PI3K/AKT/mTOR pathway is a good target for drug development, due to its involvement in HER2-mediated signalling and in the emergence of resistance to anti-HER2 therapies, such as trastuzumab. This study evaluates the activity of three different PI3K/AKT/mTOR inhibitors, i.e., BEZ235, everolimus and TAK-228 in vitro, in a panel of HER2-positive breast cancer cell lines with primary and acquired resistance to trastuzumab. We assess the antiproliferative effect and PI3K/AKT/mTOR inhibitory capability of BEZ235, everolimus and TAK-228 alone, and in combination with trastuzumab. Dual blockade with trastuzumab and TAK-228 was superior in reversing the acquired resistance in all the cell lines. Subsequently, we analyse the effects of TAK-228 in combination with trastuzumab on the cell cycle and found a significant increase in G0/G1 arrest in most cell lines. Likewise, the combination of both drugs induced a significant increase in apoptosis. Collectively, these experiments support the combination of trastuzumab with PI3K/AKT/mTOR inhibitors as a potential strategy for inhibiting the proliferation of HER2-positive breast cancer cell lines that show resistance to trastuzumab.

Introduction: KRAS is the most common driver mutation in lung cancer. ctDNA-based assessment offers advantages over tumor as a minimally invasive method able to capture tumor heterogeneity. Monitoring KRAS mutational load in ctDNA may be useful in the management of the patients., Methods: Consecutive patients diagnosed with KRAS mutant lung adenocarcinoma in the tumor biopsy were included in this study. Plasma samples were obtained at different time points during the course of the disease. KRAS mutations in plasma were quantified using digital PCR and correlated with mutations in tumor and with radiological response and progression., Results: Two hundred and forty-five plasma samples from 56 patients were analyzed. The rate of detection of KRAS mutations in plasma in our previously characterized KRAS-mutant cases was 82% overall, reaching 96% in cases with more than 1 metastatic location. The dynamics of KRAS mutational load predicted response in 93% and progression in 63% of cases, 33 and 50 days respectively in advance of radiological evaluation. Progression-free survival for patients in whom ctDNA was not detectable in plasma after treatment initiation was significantly longer than for those in whom ctDNA remained detectable (7.7 versus 3.2 months; HR: 0.44, p=0.004)., Conclusions: The detection of KRAS mutations in ctDNA showed a good correlation with that in tumor biopsy and, in most cases, predicted tumor response and progression to chemotherapy in advance of radiographic evaluation. The liquid biopsies for ctDNA-based molecular analyses are a reliable tool for KRAS testing in clinical practice., (Copyright © 2020 SEPAR. Publicado por Elsevier España, S.L.U. All rights reserved.)

The bromodomain-containing protein 4 (BRD4), a member of the bromodomain and extra-terminal domain (BET) protein family, has emerged in the last years as a promising molecular target in many tumors including breast cancer. The triple negative breast cancer (TNBC) represents the molecular subtype with the worst prognosis and a current therapeutic challenge, and TNBC cells have been reported to show a preferential sensitivity to BET inhibitors. Interestingly, BRD4 phosphorylation (pBRD4) was found as an alteration that confers resistance to BET inhibition and PP2A proposed as the phosphatase responsible to regulate pBRD4 levels. However, the potential clinical significance of pBRD4, as well as its potential correlation with the PP2A pathway in TNBC, remains to be investigated. Here, we evaluated the expression levels of pBRD4 in a series of 132 TNBC patients. We found high pBRD4 levels in 34.1% of cases (45/132), and this alteration was found to be associated with the development of patient recurrences ( p = 0.007). Interestingly, BRD4 hyperphosphorylation predicted significantly shorter overall ( p < 0.001) and event-free survival ( p < 0.001). Moreover, multivariate analyses were performed to confirm its independent prognostic impact in our cohort. In conclusion, our findings show that BRD4 hyperphosphorylation is an alteration associated with PP2A inhibition that defines a subgroup of TNBC patients with unfavorable prognosis, suggesting the potential clinical and therapeutic usefulness of the PP2A/BRD4 axis as a novel molecular target to overcome resistance to treatments based on BRD4 inhibition.

Formalin-fixed paraffin-embedded (FFPE) tissues play an irreplaceable role in cancer research. Although extensive research has been conducted for the detection of DNA, RNA and proteins in FFPE samples, literature dealing with the FFPE determination of small molecules is scarce. In this study, we aimed to explore the potential of targeted metabolomics in FFPE specimens. For that purpose, we developed a LC-MS/MS method for the quantification of acidic metabolites in FFPE samples. The method involves trimming tissue slices from FFPE blocks, deparaffinization, lysis of the tissue, o-benzyl hydroxylamine derivatization and LC-MS/MS detection. Deparaffinization and lysis steps were optimized to maximize the analytes extraction and to minimize the effect of the ubiquitous presence of some metabolites in the paraffin. Two validation approaches were applied: (i) using blank paraffin as matrix and (ii) using actual human FFPE tissue samples by standard additions. The method quantified 40 metabolites with appropriate accuracy (commonly 80-120%) and precision (CV 2-19%) in both validation approaches. LLOQs ranging 0.88-2001 pg mg -1 with low-moderate matrix effects (commonly 85-115%) were obtained. FFPE samples from 15 patients with colorectal cancer were analyzed and metabolites concentrations in tumor vs matched normal FFPE tissues were compared. Results show that tumor tissues have a well-established fingerprint including an increase in ketogenesis, a decrease in lipogenesis and an imbalance in the tricarboxylic acid cycle., (Copyright © 2020 Elsevier B.V. All rights reserved.)

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., (Copyright © 2020 Pattanayak, Garrido-Cano, Adam-Artigues, Tormo, Pineda, Cabello, Alonso, Bermejo, Hernando, Martínez, Rovira, Albanell, Rojo, Burgués, Cejalvo, Lluch and Eroles.)

Mechanisms driving tumor progression from less aggressive subtypes to more aggressive states represent key targets for therapy. We identified a subset of luminal A primary breast tumors that give rise to HER2-enriched (HER2E) subtype metastases, but remain clinically HER2 negative (cHER2-). By testing the unique genetic and transcriptomic features of these cases, we developed the hypothesis that FGFR4 likely participates in this subtype switching. To evaluate this, we developed 2 FGFR4 genomic signatures using a patient-derived xenograft (PDX) model treated with an FGFR4 inhibitor, which inhibited PDX growth in vivo. Bulk tumor gene expression analysis and single-cell RNA sequencing demonstrated that the inhibition of FGFR4 signaling caused molecular switching. In the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) breast cancer cohort, FGFR4-induced and FGFR4-repressed signatures each predicted overall survival. Additionally, the FGFR4-induced signature was an independent prognostic factor beyond subtype and stage. Supervised analysis of 77 primary tumors with paired metastases revealed that the FGFR4-induced signature was significantly higher in luminal/ER+ tumor metastases compared with their primaries. Finally, multivariate analysis demonstrated that the FGFR4-induced signature also predicted site-specific metastasis for lung, liver, and brain, but not for bone or lymph nodes. These data identify a link between FGFR4-regulated genes and metastasis, suggesting treatment options for FGFR4-positive patients, whose high expression is not caused by mutation or amplification.

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., (©2020 American Association for Cancer Research.)