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Background: CDK4/6 inhibitors have significantly improved the survival of patients with HR-positive/HER2-negative breast cancer, becoming a first-line treatment option. However, the development of resistance to these inhibitors is inevitable. To address this challenge, novel strategies are required to overcome resistance, necessitating a deeper understanding of its mechanisms. Recent research has identified several dysregulated genes in CDK4/6 inhibitors-resistant breast cancer, but the underlying mechanism is complex due to tumor heterogeneity and warrants further investigation., Methods: RNA sequencing and KEGG pathway analysis was carried out to identify the mainly dysregulated genes in CDK4/6 inhibitors-resistant breast cancer cells. The effects of CXCR4 knockdown and overexpression via siRNAs and plasmids transfection were examined by mammosphere formation, RT-qPCR, flow cytometry, MTT and colony formation assays. The regulation mechanisms were analyzed by RT-qPCR, western blotting and immunofluorescence experiments. Mouse xenografts were used to analyze the role of CXCR4 in regulation palbociclib sensitivity in vivo. Additionally, we collected the clinical samples and performed immunohistochemistry to analyze the clinical significance of CXCR4., Results: In our study, we focused on cancer stem cells, a critical contributor to cancer metastasis and therapy resistance, and detected an upregulation of stemness in our established palbociclib-resistant ER-positive breast cancer cells. Additionally, our research pinpointed CXCR4 as a pivotal gene responsible for maintaining cancer stemness and promoting palbociclib resistance. Mechanistically, CXCR4 activates the WNT5A/β-catenin signaling pathway by enhancing the expression of WNT5A and β-catenin, facilitating the nuclear translocation of β-catenin protein. Targeting CXCR4 using siRNAs or small molecular inhibitors effectively reduces cancer stemness and reverses palbociclib resistance both in vitro and in vivo. Clinical sample analysis further underscores the overactivation of the CXCR4/WNT5A/β-catenin axis in palbociclib-resistant breast cancer, suggesting CXCR4 as a potential biomarker for predicting resistance to CDK4/6 inhibitors., Conclusions: Collectively, our study demonstrates that CXCR4 overexpression plays a vital role in maintaining breast cancer stemness and promoting resistance to CDK4/6 inhibitors through the activation of the WNT5A/β-catenin pathway. Targeting CXCR4 may offer a promising therapeutic approach for advanced CDK4/6 inhibitor-resistant ER-positive breast cancer., Competing Interests: Declarations. Ethics approval and consent to participate: All clinical samples were collected with signed informed consent and ethics approval from Sun Yat-Sen Memorial Hospital. Consent for publication: The content of this paper has not been submitted to any other scientific publications. All the authors have declared that no financial conflict of interest exists. All authors have approved the submission of this work for publication in Breast Cancer Research. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

This study investigates the role of flavonoid Icaritin (ICT) in estrogen-deficient ovariectomized (OVX) female mice by activating the Estrogen receptor (ER)/ Phosphatidylinositol 3-kinase (PI3K)/Protein kinase B (Akt) signaling pathway, potentially delaying Parkinson's disease (PD) progression post-castration. Seventy-five 8-week-old C57BL/6J female mice underwent ovariectomy, followed by MPTP (20 mg/kg) injection for 7 days. ICT (20 mg/kg) was administered for 14 days, and motor function was assessed using various behavioral tests. Serum estradiol, FSH, LH levels were measured by ELISA, and the expression of PI3K/Akt signaling and apoptosis proteins was analyzed by Western blot. Bone mineral density was assessed via dual-energy X-ray absorption, and histology of the uterus and femur was performed. Results showed that ICT alleviated MPTP-induced motor deficits, increased serum estradiol, and improved uterine atrophy. At the molecular level, ICT activated the PI3K/Akt pathway, reduced apoptosis, and mitigated PD symptoms and osteoporosis induced by OVX. These findings suggest ICT may offer therapeutic potential in managing OVX-induced motor dysfunction and PD., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethical statement: Our experimental research was reported according to the ARRIVE guidelines ( https://arriveguidelines.org ) and adheres to animal ethics. All experiments were approved by the Animal Experiment Ethics Committee of Zunyi Medical University (No.: (2019) 2-231, March 11, 2019)., (© 2025. The Author(s).)

Background: The PALLAS trial investigated the addition of palbociclib to standard adjuvant endocrine therapy to reduce breast cancer recurrence. This pre-specified analysis was conducted to determine whether adjuvant palbociclib benefited patients diagnosed with lower risk stage IIA disease compared to those with higher stage disease., Methods: PALLAS was an international, multicenter, randomized, open-label, phase III trial, representing a public-private partnership between Pfizer, the Austrian Breast Cancer Study Group, and the U.S. ALLIANCE Foundation. Patients diagnosed with stage II-III, hormone-receptor-positive, HER2/neu negative breast cancer within 12 months of diagnosis had completed all definitive therapy aside from endocrine therapy (started within 6 months prior to study entry) were eligible. All patients were required to submit a formalin-fixed paraffin-embedded (FFPE) tumor block. Patients were randomly assigned 1:1 to receive standard adjuvant endocrine therapy (of physicians' choice) for at least 5 years with or without 2 years of palbociclib, administered orally at a starting dose of 125 mg daily, given for 21 days followed by a 7-day break., Results: A total of 5,796 patients with HR + /HER2- early breast cancer (including 1,010 with stage IIA) were enrolled. Median follow-up was 50 months for stage IIA patients and 43.1 months overall. In the stage IIA cohort, 4-year iDFS in the palbociclib arm was 92.9% versus 92.1% for ET alone (HR 0.75, 95%CI 0.48-1.19, p = 0.23). There was no differential benefit by histologic grade, chemotherapy receipt, age, or anatomic/clinical risk. Additionally, no benefit to palbociclib was seen in this cohort in invasive breast cancer-free survival (iBCFS), locoregional relapse-free survival (LRFS), distant relapse-free survival (DRFS), or overall survival (OS). For the stage IIB/III patients, 4-year iDFS was 85.3% for palbociclib + ET versus 83.6% for ET alone (HR 0.91, 95% CI 0.77-1.07, p = 0.24)., Conclusions and Relevance: While there were substantial differences in outcome for stage IIA versus IIB/III patients at 4 years of follow-up, the addition of 2 years of palbociclib did not improve outcomes for patients, regardless of stage., Trial Registration: ClinicalTrials.gov number NCT02513394 Registered 30 Jul 2015., Competing Interests: Declarations. Ethics approval and consent to participate: In the U.S., the study protocol was approved by the institutional review board and the Advarra Protocol Approval number is Pro00034499. Outside the U.S., the trial was approved by respectively responsible institutional review boards and ethics committees. All analyzed patients provided written informed consent, and the trial was performed in strict accordance with ICH GCP guidelines (ClinicalTrials.gov identifier: NCT02513394, EudraCT 2014-005181-30). Competing interests: Institutional research grants from Novartis, Pfizer, Genentech, and Neogenomics. The authors declare no competing interests., (© 2024. The Author(s).)

Breast cancer (BC) is classified based on the expression of histopathological markers, namely, estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor 2 (HER2). Carcinomas with apocrine differentiation (CAD) are classified based on morphology. Androgen receptor (AR) is highly expressed in CAD; however, no study has comprehensively examined AR-related proteins in CAD. Therefore, we examined the expression of AR-related proteins and AR, compared protein expression patterns between morphologically identified CAD and other BC subtypes, and investigated CAD characteristics. We performed immunohistochemistry for AR and various AR-related proteins in 66 invasive ductal carcinoma (32 ER+/PgR+/HER2-, 8 ER+/PgR+/HER2+, 12 ER-/PgR-/HER2+, and 14 ER-/PgR-/HER2- [triple-negative breast cancer)), 21 invasive lobular carcinoma, and 27 CAD cases. In the CAD group, all cases were AR-positive; some AR-related proteins were highly expressed. Nuclear phosphorylated-mammalian target of rapamycin was highly expressed in CAD cases compared with that in other BC groups, with a 33.3% sensitivity and 97.7% specificity. AR-expressing CAD cases exhibited high expression of other AR-related proteins. Specifically, the combination of AR+, GCDFP15+, and ER - or AR+, FOXA1+, and ER - may be useful for the diagnosis and treatment of AR-positive BC and CAD. These results may assist in androgen-related molecular targeted therapy research., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

To better understand drug resistance mechanisms to CDK4/6 inhibitors and inform precision medicine, we analyze real-world multi-omics data from 400 HR+/HER2- metastatic breast cancer patients treated with CDK4/6 inhibitors plus endocrine therapies, including 200 pre-treatment and 227 post-progression samples. The prevalences of ESR1 and RB1 alterations significantly increase in post-progression samples. Integrative clustering analysis identifies three subgroups harboring different resistance mechanisms: ER driven, ER co-driven and ER independent. The ER independent subgroup, growing from 5% pre-treatment to 21% post-progression, is characterized by down-regulated estrogen signaling and enrichment of resistance markers including TP53 mutations, CCNE1 over-expression and Her2/Basal subtypes. Trajectory inference analyses identify a pseudotime variable strongly correlated with ER independence and disease progression; and revealed bifurcated evolutionary trajectories for ER-independent vs. ER-dependent drug resistance mechanisms. Machine learning models predict therapeutic dependency on ESR1 and CDK4 among ER-dependent tumors and CDK2 dependency among ER-independent tumors, confirmed by experimental validation., Competing Interests: Competing interests: The authors declare no competing non-financial Interests but the following competing financial interests. All authors were employees of Pfizer Inc. at the time the work was performed., (© 2025. The Author(s).)

The efficacy of immunotherapy for estrogen receptor-positive/HER2-negative (ER+/HER2-) metastatic breast cancer (MBC) has not been proven. We conduct a phase 1b/2 trial to assess the efficacy of combining pembrolizumab (anti-PD1 antibody), exemestane (nonsteroidal aromatase inhibitor), and leuprolide (gonadotropin-releasing hormone agonist) for 15 patients with premenopausal ER+/HER2- MBC who had failed one to two lines of hormone therapy (HT) without chemotherapy. The primary endpoint of progression-free survival rate at 8 months (i.e., 64.3%) is achieved. Moreover, 5 of the 14 evaluable subjects exhibited partial responses (overall response rate = 35.7%). The combination of anti-PD1 antibody and anti-hormone therapy is associated with an enhanced immunoreactive microenvironment influencing treatment efficacy, as observed in pre- and post-treatment tumor samples through NanoString analysis. Post-treatment tumors are associated with increased immune response and immune cells. The findings indicate that combining HT with anti-PD1 antibody is a promising treatment strategy for patients with premenopausal ER+/HER2- MBC. This study was registered at ClinicalTrials.gov (NCT02990845)., Competing Interests: Declaration of interests I.-C.C. received honoraria from AstraZeneca, Daiichi Sankyo, Gilead, Merck Sharp & Dohme, Novartis, Pfizer, and Sanofi and received research grants from AstraZeneca, Merck Sharp & Dohme, and Novartis. D.-Y.C. received honoraria from Amgen, AstraZeneca, Daiichi Sankyo, Eisai, Eli Lilly, MSD, Novartis, ONO Pharma, Pierre Faber, Pfizer, Roche, Sanofi, and TTY Biopharm. T.W.-W.C. received honoraria from Roche, Novartis, Eli Lilly, Eisai, Pfizer, Daiichi Sankyo, and AstraZeneca. Y.-S.L. received honoraria from Merck Sharp & Dohme and Pfizer and received research grants from Merck Sharp & Dohme and Pfizer., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Cancer remains a leading cause of morbidity and mortality worldwide, highlighting the urgent need for novel therapeutic agents. This study investigated the synthesis and biological evaluation of O -alkyl ( E )-chalcone derivatives ( 4a - 4v ) as potential anticancer agents. The compounds were synthesized via aldol condensation of substituted aldehydes and acetophenones, with structures confirmed by IR, NMR, and mass spectrometry. In vitro cytotoxicity assays revealed varying effectiveness, with compounds 4a , 4b , 4q , and 4v exhibiting potent activity against MDA-MB-231 and MCF-7, showing IC 50 values between 2.08 and 13.58 µM, besides HCT-116 and HeLa cancer cell lines (IC 50 values between 6.59 and 22.64 µM). Notably, compound 4b displayed remarkable selectivity, with an IC 50 of 54.59 µM against the non-cancerous WI-38 cell line. Additionally, protein kinase inhibition assays indicated that compounds 4b and 4q effectively inhibited EGFR and VEGFR-2, with 4b outperforming the standard inhibitor erlotinib. Molecular docking studies of compound 4q showed strong binding affinities in the ATP-binding pockets of EGFR, HER2, VEGFR2, and CDK2. In silico analyses further highlighted the favorable pharmacokinetic properties of compound 4q , underscoring its potential as a selective tyrosine kinase inhibitor. These findings suggest the therapeutic promise of O -alkyl ( E )-chalcone derivatives in cancer treatment.

Introduction: CDK4/6 inhibitors in combination with aromatase inhibitors (AIs) are the standard first-line treatment for hormone receptor-positive (HR+), HER2-negative (HER2-) metastatic breast cancer. Landmark trials have demonstrated a comparable progression-free survival (PFS) across CDK4/6 inhibitors, but the overall survival (OS) outcomes have varied. This study aimed to evaluate the real-world PFS and OS for palbociclib and ribociclib when combined with AIs in patients with HR+/HER2- advanced breast cancer., Materials and Methods: This was a retrospective chart review of adult patients with HR+/HER2- metastatic breast cancer treated at a single academic center between 1 January 2015 and 1 December 2022. The baseline demographics, clinical characteristics, and treatment details were extracted. A Kaplan-Meier analysis was used to estimate the PFS and OS, and differences between the treatment groups were assessed using the log-rank test. Cox proportional hazards models were constructed to adjust for confounding factors., Results: Seventy-five patients were included in the final analysis. The cohort was predominantly female (98.7%) and postmenopausal (77.3%), with 52.0% having de novo stage IV disease. Palbociclib was prescribed to 74.7% of the patients, and ribociclib to 25.3%. The patients receiving ribociclib were significantly younger (57.6 vs. 67.5 years, p = 0.013) and more likely to be premenopausal (42.1% vs. 5.4%, p < 0.001). The real-world median PFS and OS for palbociclib were 20.3 months (95% CI: 14.8-46) and 37.2 months (95% CI: 20.3-not reached [NR]), respectively. For ribociclib, the median PFS and OS were not reached. The Cox proportional hazards models adjusting for age and menopausal status found no significant differences between ribociclib and palbociclib for the PFS (HR = 0.92, p = 0.86) or OS (HR = 0.95, p = 0.92)., Conclusion: In this real-world analysis, palbociclib demonstrated a median PFS consistent with the results from landmark trials, although the observed OS was shorter. The ribociclib-treated patients had a numerically longer PFS and OS compared with those treated with palbociclib, but the differences were not statistically significant. The discontinuation rates were similar between the two groups.

Breast cancer (BrCa) is a complex and heterogeneous disease with diverse molecular subtypes, leading to varied clinical outcomes and posing significant treatment challenges. The increasing global burden of BrCa, particularly in low- and middle-income countries, underscores the urgent need for more effective therapeutic strategies. The androgen receptor (AR), expressed in a substantial proportion of breast cancer cases, has emerged as a potential biomarker and therapeutic target. In breast cancer, AR exhibits diverse functions across subtypes, often interacting with other hormone receptors, thereby influencing tumor progression and treatment responses. This intricate interplay is further complicated by the presence of constitutively expressed AR splice variants (AR-Vs) that drive resistance to AR-targeting therapies through structural rearrangements in the domains and activation of aberrant signaling pathways. Although AR-targeting drugs, initially developed for prostate cancer (PCa), have shown promise in AR-positive breast cancer, significant gaps remain in understanding AR's precise functions and therapeutic potential. The systemic management of breast cancer is guided primarily by theranostic biomarkers; ER, PR, HER2, and Ki67 which also dictate the breast cancer classification. The ubiquitous expression of AR in BrCa and the emergence of AR-Vs can assist the management of disease complementing the standard of care. This article provides a comprehensive overview of AR and its splice variants in the context of breast cancer, highlighting their prognostic and predictive value across different subtypes looking beyond the conventional ER, PR, and HER2 status. This review also raises the possibility of using AR splice variants in predicting tumor aggressiveness. From the settings of developing nations, this may provide useful insight by integrating recent advances in AR-targeted therapies and exploring their translational potential, emphasizing the critical need for further research to optimize AR-based therapeutic strategies for breast cancer management., Competing Interests: Declarations. Ethics approval and consent to participate: No ethics approval and consent to participate were required for this review article, as it does not involve primary data collection involving human participants or animals. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Breast cancer (BC) patient-derived xenografts (PDX) are relevant models for precision medicine. However, there are no collections derived from South American BC patients. Since ethnicity significantly impacts clinical outcomes, it is necessary to develop PDX models from different lineages. Our goals were to a) develop BC PDX from our population; b) characterize the expression of estrogen (ER), progesterone (PR), androgen (AR) and glucocorticoid (GR) receptors, basal and luminal cytokeratins, EGFR and HER2; c) identify PDX mutations; d) evaluate the response to treatments selected based on their biological and genetic features, and e) perform BC tissue cultures (BCTC) from PDX tissues and compare in vivo and ex vivo results. Surgical fragments were maintained in a culture medium and inoculated subcutaneously into untreated NSG female mice, or treated with estradiol pellets. Other fragments were fixed in formalin for diagnosis and immunohistochemistry, and a third piece was frozen at -80°C for molecular studies or whole exome-sequencing. Tumors were serially transplanted into NSG mice. Once the PDX was established, in vivo and ex vivo drug responses were evaluated. Eight PDX were established: two ER + [BC-AR685 (PR +) and BC-AR707 (PR-)], one from a triple-negative (TN) recurrence whose primary tumor was ER + (BC-AR485), one HER2 + (BC-AR474) and four TN primary tumors (BC-AR553, BC-AR546, BC-AR631 and BC-AR687). BC-AR685 had higher levels of PR isoform A than isoform B and was sensitive to mifepristone, tamoxifen, and palbociclib. BC-AR707 was inhibited by tamoxifen and testosterone. BC-AR474 was inhibited by trastuzumab and trastuzumab emtansine. BC-AR485 was sensitive to doxorubicin and resistant to paclitaxel in vivo and ex vivo. BC-AR687 carried a PIK3CA (C420R) mutation and was sensitive to alpelisib and mTOR inhibitors. All PDX expressed AR with varying intensities. GR and AR were co-expressed in the ER + tumors and in 3 TN PDX. We report the first PDX originated from South American countries that were genetically and biologically characterized and may be used in precision medicine studies. PDX expressing AR and/or GR are powerful tools to evaluate different endocrine treatment combinations even in TN tumors., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethics approval and consent to participate: All patients signed a written informed consent to participate in this project. The study was approved by the Hospital´s authorities and from the Enrique Segura IBYME IRB # 021–2017. Animal experiments were approved by the IBYME-IACUC committee (058–2017). Consent for publication: All authors agree with the contents of the manuscript and agree for its publication., (© 2025. The Author(s).)

The benefit of adjuvant chemotherapy (CT) for hormone receptor-negative T1a and T1bN0M0 breast cancer remains uncertain. Our study was to explore prognostic value and identify candidates of adjuvant CT for these patients. The data of hormone receptor-negative T1a and T1bN0M0 breast cancer patients were extracted from the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2015. All patients were divided into two groups according to the history of adjuvant CT namely the CT group and the no CT (No CT) group. Univariate and multivariate Cox regression analysis were utilized to identify factors linked with cancer specific survival (CSS) and overall survival (OS) for the patients. Kaplan-Meier method was employed to determine survival benefit of adjuvant CT. A total of 3889 patients were included. After propensity score-matching, 1217 patients were assigned to the CT group and 1217 patients were assigned to the No CT group respectively. Based on multivariate Cox regression analysis of OS, older age, single, T1b stage, triple-negative tumor and absence of adjuvant CT were identified as risk factors related to OS. Besides, multivariable Cox regression analysis of CSS showed significant association between grade III+IV, T1b stage, triple-negative tumor and absence of adjuvant CT and CSS. The results from Kaplan-Meier curves revealed that adjuvant CT could bring OS benefit for these patients with more than two risk factors and could improve CSS for the patients with more than one risk factor. Our study supports the implementation of individualized strategies for hormone receptor-negative T1a and T1bN0M0 breast cancer patients. Adjuvant CT was recommended for potential beneficial patients after undertaking a risk-benefit discussion., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethical statement: The data are publicly available, the informed consent of patients and ethical approval were waived by the Ethics Committee of the First Affiliated Hospital of Nanchang University., (© 2025. The Author(s).)

Anti-estrogen endocrine therapies greatly improve survival of estrogen receptor positive (ER + ) breast cancer. Unfortunately, about 30% of patients do not respond to endocrine therapies initially. We previously showed that deubiquitinase USP35 and ERα act in a positive feedback loop to promote the carcinogenesis of ER+ breast cancer although it is unclear whether USP35 regulates cell death in ER+ breast cancer. In this study, we uncovered that USP35 inhibited ferroptosis of ER+ breast cancer cells. Mechanistically, USP35 interacted with, deubiquitinated, and stabilized BRD4. Consequentially, BRD4 mediated USP35-induced SLC7A11 upregulation, inhibiting ferroptosis and promoting the growth of ER+ breast cancer cells. Furthermore, BRD4 inhibitor (+)-JQ-1 inhibited USP35-enhanced tumorigenesis in vivo. Our findings demonstrated that the USP35-BRD4-SLC7A11 axis contributes to the growth of ER+ breast cancer by inhibiting ferroptosis. Targeting USP35 together with ferroptosis inducer may represent a potential promising strategy for treating ER+ breast cancer that does not respond to endocrine therapies., Competing Interests: Competing interests: The authors declare no competing interests. Ethics statements: All human breast tumor samples were obtained from patients with informed consent. The current study (protocol# 2019006) was approved by the Institutional Review Board for human study of Wenzhou Medical University and conducted according to the principles expressed in the Helsinki Declaration. The animal study (protocol# wydw2023-0484) was approved by the Institutional Animal Care and Use Committee of Wenzhou Medical University and conducted in compliance with relevant local guidelines., (© 2025. The Author(s).)

Estrogen-related receptor α (ERRα) is dysregulated in many types of cancer and exhibits oncogenic activity by promoting tumorigenesis and metastasis of cancer cells. However, its defined role in renal cell carcinoma (RCC) has not been fully elucidated. To reveal the biological function of ERRα and determine the underlying regulatory mechanism in RCC, the quantitative proteomics analysis and mechanism investigation were conducted. The results demonstrated that ERRα promoted the proliferation and tumorigenesis of RCC cells by maintaining lysosome-dependent autophagy flux. ERRα inhibition impaired the transcriptional expression of LAMP2 and VAMP8 and blocked the fusion of autophagosomes with lysosomes, causing the impairment of the autophagy-lysosome pathway and tumor repression in RCC. Moreover, VHL mutant-induced hyperactive hypoxia signaling in RCC triggered p300/CBP-mediated acetylation at the DNA-binding domain of ERRα, and this acetylation promoted its affinity toward targeting DNA and Parkin-mediated ubiquitination and proteasome-dependent degradation. This regulatory model enhanced ERRα transactivation on the expression of LAMP2 and VAMP8, which then maintained autophagy flux and RCC progression. Pharmaceutical inhibition on ERRα acetylation-mediated autophagy-lysosome pathway led to growth repression and sunitinib sensitivity of RCC cells. Taken together, this study uncovered a novel regulatory mechanism of acetylation contributing to the transcriptional performance and the oncogenic role of ERRα in RCC progression by modulating the autophagy-lysosome pathway. These findings might provide a novel approach for the clinical diagnosis and resolution of sunitinib resistance of RCC., Competing Interests: Competing interests: The authors declare no competing interests. Ethics approval: All animal experiments were performed in accordance with the regulation set by the Ethics Committee for Biology and Medical Science of Binzhou Medical University, the ethics approval number is #2023-35., (© 2025. The Author(s).)

Lerociclib (GB491), a highly selective oral CDK4/6 inhibitor, has displayed anti-tumor activity and differentiated safety and tolerability profile in previous ph1/2 clinical trials. The LEONARDA-1, a randomized, double-blind, phase III study, was conducted to evaluate the efficacy and safety of lerociclib in HR+/HER2- locally advanced or metastatic breast cancer patients, who had relapsed or progressed on prior endocrine therapy. A total of 275 patients were randomized at 1:1 ratio to receive lerociclib (137 patients, 150 mg twice daily) or placebo (138 patients) plus fulvestrant. Progression-free survival (PFS) assessed by investigators was significantly improved in lerociclib arm versus placebo arm (11.07 vs 5.49 months; hazard ratio, 0.451, 95% CI: 0.311-0.656, P = 0.000016), meeting the pre-specified primary endpoint. The secondary endpoints included PFS assessed by Blinded Independent Central Review (BICR), objective response rate (ORR), duration of response (DOR), disease control rate (DCR), clinical benefit rate (CBR), overall survival (OS), safety and tolerability and pharmacokinetic profile. DOR is not reported, and OS data was immature at the data cut-off but unplanned ad hoc analysis is reported. These findings support lerociclib plus fulvestrant as a treatment option for patients with HR+/HER2- endocrine-resistant advanced breast cancer (ABC). (Funded by Genor Biopharma; LEONARDA-1 ClinicalTrials.gov identifier, NCT05054751.)., Competing Interests: Competing interests: The authors declare the following competing interests: B.X. discloses receiving advisory fees from Novartis and AstraZeneca. D.Z. and T.L. were employees of Genor Biopharma at the time of the study. The other authors declare no competing interests., (© 2025. The Author(s).)

Persistent organic pollutants (POPs) are a group of organic chemical compounds. Contradictory results have emerged in epidemiological studies attempting to elucidate their relationship with breast cancer risk. This study explored the relationship between dietary exposures to multiple POPs and ER-positive breast cancer risk in the French E3N cohort study, using three different approaches to handle multicollinearity among exposures. Intakes of 81 POPs were estimated using food consumption data from a validated semi-quantitative food frequency questionnaire and food contamination data. In the first approach, hierarchical clustering was performed to identify clusters of correlated POPs. For each cluster, the levels of POPs belonging to it were averaged. These average levels were then included in a Cox model to estimate their associations with ER-positive breast cancer occurrence. The second and third approaches applied in the present study were Principal component Cox regression (PCR-Cox) and partial least squares Cox regression (PLS-Cox) respectively, both being dimension-reduction methods (respectively unsupervised and supervised) coupled to a Cox model, used to identify principal components of POPs and to estimate their associations with ER-positive breast occurrence. All models were adjusted for potential confounders previously identified using a directed acyclic graph. The study included 66,722 women with a median follow-up of 20.3 years, during which 3,739 developed an incident ER-positive breast cancer. The variable clustering method did not identify any association between the averaged variables and ER-positive breast cancer risk. Five components were retained using both the PCR-Cox and PLS-Cox methods explaining 82% and 77% of the variance in the initial exposure matrix respectively. Among these components, none was significantly associated with the occurrence of ER-positive breast cancer. This study provides an illustrative example of the application of three distinct statistical methods in the context of highly correlated environmental exposures, discussing their potential relevance and limitations within this specific framework., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethical approval: The study was approved by the French National Commission for Data Protection and Privacy (ClinicalTrials.gov identifier: NCT03285230). All methods were carried out in accordance with relevant guidelines and regulations. Informed consent: All participants included in this study gave written informed consent., (© 2025. The Author(s).)

Purpose: To evaluate the prognostic significance of progesterone receptor (PR) expression and the PIK3CA mutation status in HR+/HER2 - breast cancer patients, with the goal of screening patients who may derive the greatest benefit from PI3K-targeted therapy., Methods: A retrospective analysis was conducted on 152 HR+/HER2 - breast cancer patients stratified by PR expression levels and PIK3CA mutation status. The study population was divided into groups on the basis of a median PR threshold of 50% and further subdivided by PIK3CA mutation status. To evaluate the variability of clinicopathologic features among these groups, t tests and ANOVA were employed. The influence of these variables on survival was analyzed via Cox regression. Additionally, a risk prediction model was developed using the PR expression level and PIK3CA mutation status. The prognostic utility of this model was examined via both Kaplan‒Meier (KM) survival curves and receiver operating characteristic (ROC) analyses. These methods have also been utilized to explore the associations between clinicopathologic parameters and clinical outcomes with respect to survival prediction and prognosis., Results: Significant differences in age, ER expression, and Ki67, HER2, and PIK3CA mutation status were detected between the groups (P < 0.05). Specifically, elevated PR expression was correlated with lower levels of Ki67 and low HER2 expression. The presence of a PIK3CA mutation was significantly linked to survival outcomes according to both univariate and multivariate Cox regression analyses. Moreover, ROC analysis revealed that models incorporating both PR expression and PIK3CA mutation status achieved the highest level of diagnostic precision (AUC = 0.82)., Conclusion: PR expression and PIK3CA mutation status are significant prognostic markers in HR+/HER2 - breast cancer patients. Assessing these biomarkers in combination can enhance prognostic stratification, potentially guiding more informed clinical decision-making., Competing Interests: Declarations. Ethics approval and consent to participate: This study was approved by the Ethics Committee of Shanxi Cancer Hospital, China, and has been performed in accordance with the ethical standards laid down in the 1964 Helsinki Declaration and its later amendments. This article does not contain any studies with animals performed by any of the authors. Informed consent was obtained from all individual participants included in the study. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Recent evidence indicates that endocrine resistance in estrogen receptor-positive (ER+) breast cancer is closely correlated with phenotypic characteristics of epithelial-to-mesenchymal transition (EMT). Nonetheless, identifying tumor tissues with a mesenchymal phenotype remains challenging in clinical practice. In this study, we validated the correlation between EMT status and resistance to endocrine therapy in ER+ breast cancer from a transcriptomic perspective. To confirm the presence of morphological discrepancies in tumor tissues of ER+ breast cancer classified as epithelial- and mesenchymal-phenotypes according to EMT-related transcriptional features, we trained deep learning algorithms based on EfficientNetV2 architecture to assign the phenotypic status for each patient utilizing hematoxylin & eosin (H&E)-stained slides from The Cancer Genome Atlas database. Our classifier model accurately identified the precise phenotypic status, achieving an area under the curve (AUC) of 0.886 at the tile-level and an AUC of 0.910 at the slide-level. Furthermore, we evaluated the efficacy of the classifier in predicting endocrine response using data from an independent ER+ breast cancer patient cohort. Our classifier achieved a predicting accuracy of 81.25%, and 88.7% slides labeled as endocrine resistant were predicted as the mesenchymal-phenotype, while 75.6% slides labeled as sensitive were predicted as the epithelial-phenotype. Our work introduces an H&E-based framework capable of accurately predicting EMT phenotype and endocrine response for ER+ breast cancer, demonstrating its potential for clinical application and benefit., Competing Interests: Declarations. Ethics approval and consent to participate: The research ethics committee of the Second Affiliated Hospital of Zhejiang University approved this retrospective study (approval no. 20220731) and waived the requirement for informed consent since it solely utilized pre-existing medical data. This study was conducted in compliance with the ethical standards of the participating institution and adhered to the tenets outlined in the Declaration of Helsinki. Competing interests: The authors declare no competing interests. Conflict of interest: The authors declare no competing interests., (© 2025. The Author(s).)

Breast cancer became the most prevalent malignancy among women, and HER2 expression status is critical for treatment decisions. With the emergence of ADC drugs, HER2 low-expressing patients who previously did not respond well to traditional anti-HER2 therapies may now benefit. In this study, immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) were applied to assess HER2 expression in 349 patients with HER2-non-positive breast cancer. Our analysis revealed that HER2-low tumors exhibited fewer grade III tumors (39.74% and 55.65%, respectively, P = 0.005) and higher positivity for estrogen receptor (ER, 88.89% vs. 61.74%, P < 0.001) and progesterone receptor (PR, 84.62% vs. 57.39%, P < 0.001) compared to HER2-ZERO tumors. Of the 349 cases, IHC was ultimately evaluated in 327, the antibodies demonstrated only 64.22% (95% CI: 58.76-69.42%) agreement between clone 4B5 and clone EP3. Pathologist 1, who had more extensive working experience, demonstrated higher consistency (94.19%) with the gold standard when using clone EP3, compared to Pathologist 2 (74.31%). FISH analysis revealed significant differences in HER2/CEP17 ratio and average HER2 copy numbers between HER2-ZERO and HER2-low tumors, but no clear cut-off value could be identified. Notably, HER2/CEP17 ratio mostly between 1 and 2, with HER2-ZERO tumors primarily ≤ 1.4, and average HER2 copy numbers were mostly ≥ 2 and < 4, with HER2-ZERO tumors primarily ≤ 2.5. Despite distinct clinicopathological features, FISH remains inadequate for distinguishing HER2-low from HER2-ZERO expression. Further studies are needed to improve HER2 assessment in this challenging subset of patients., Competing Interests: Declarations. Conflict of interest: The authors have no conflicts of interest to declare., (© 2025. The Author(s).)

Evidence indicates a bidirectional link between depressive symptoms and neuroinflammation. This study evaluated chronic cannabidiol (CBD) treatment effects in male and female rats subjected to the unpredictable chronic mild stress (UCMS) model of depression. We analyzed the gene expression related to neuroinflammation, cannabinoid signaling, estrogen receptors, and specific microRNAs in the ventromedial prefrontal cortex (vmPFC), CA1, and ventral subiculum (VS). UCMS influenced immobility in a sex-specific manner, increasing it in males and decreasing it in females, effects that were reversed by CBD. CBD also normalized the UCMS-induced upregulation of tumor necrosis factor α (TNF-α) in the CA1 and VS in males. In both sexes, UCMS induced the upregulation of the nuclear factor kappa B subunit 1 (NF-κB1) gene in the VS, which was unaffected by CBD. Additionally, CBD reversed CB1 downregulation in the VS of males but not in the vmPFC of either sex. In males, CBD restored the UCMS-induced downregulation of VS estrogen receptor genes ERα and ERβ. UCMS also altered miR-146a-5p expression, downregulating it in females (VS) and upregulating it in males (CA1), with no CBD effect. These findings highlight the sex-specific mechanisms of CBD's antidepressant effect, with hippocampal neuroinflammatory and estrogenic pathways playing a key role in males.

To assess whether metabolic syndrome can be used as a reference index to evaluate the efficacy of neoadjuvant chemotherapy treatment for breast cancer (BC). Seventy cases of female BC patients who received neoadjuvant chemotherapy treatment and surgical treatment at the Glandular Surgery Department of Hebei Provincial People's Hospital from January 2021 to December 2023 were retrospectively collected, and clinical data such as puncture pathology were recorded. The clinical data were analyzed by 1-way analysis using the χ2 test, and further multifactorial logistic regression analysis was performed for statistically significant differences. The independent risk factor metabolic syndrome (MetS) and its components were plotted in the receiver operating characteristic curve (ROC) curve and baseline graph by R Studio 4.41 software, and the meaningful components were plotted in the column graph by lasso regression analysis for internal validation, and the quality of the model was evaluated by the ROC curve and calibration graph, and then the clinical decision curve analysis was used to evaluate the clinical effectiveness of the model. The neoadjuvant efficacy was statistically associated with whether the patient was first diagnosed between 45 and 55 years of age, estrogen receptors (ER), progesterone receptors (PR) expression status, Her-2 expression status, and whether the patient had MetS, as determined by univariate analysis through χ2 (P < .05). On multifactorial binary logistic regression analysis, ER, PR status, Her-2 status, and the presence of MetS were statistically significant (P < .05) for the efficacy of neoadjuvant chemotherapy. Patients with MetS were less likely to achieve complete pathological remission than those without MetS. MetS and its components were analyzed by lasso regression analysis with RStudio 4.41 software to conclude that hypertension, hyperglycemia, and high-density lipoprotein were all correlates affecting the pathologic complete response (pCR), and a column-line graph was plotted, with a C-index of 0.76, indicating a good predictive efficacy. ER, PR status, Her-2 status and the presence of MetS are independent predictors for assessing the efficacy of neoadjuvant chemotherapy in BC, and MetS can be used as a predictor of the efficacy of neoadjuvant chemotherapy. Clinical references are provided., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2025 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Patients with estrogen receptor (ER)-positive breast cancer (BC) can be treated with endocrine therapy targeting ER, however, metastatic recurrence occurs in 25% of the patients who have initially been treated. Secreted proteins from tumors play important roles in cancer metastasis but previous methods for isolating secretory proteins had limitations in identifying novel targets., Methods: We applied an in situ secretory protein labeling technique using TurboID to analyze secretome from tamoxifen-resistant (TAMR) BC. The increased expression of LGALS3BP was validated using western blotting, qPCR, ELISA, and IF. Chromatin immunoprecipitation was applied to analyze estrogen-dependent regulation of LGALS3BP transcription. The adhesive and angiogenic functions of LGALS3BP were evaluated by abrogating LGALS3BP expression using either shRNA-mediated knockdown or a neutralizing antibody. Xenograft mouse experiments were employed to assess the in vivo metastatic potential of TAMR cells and the LGALS3BP protein. Clinical evaluation of LGALS3BP risk was carried out with refractory clinical specimens from tamoxifen-treated ER-positive BC patients and publicly available databases., Results: TAMR secretome analysis revealed that 176 proteins were secreted at least 2-fold more from MCF7/TAMR cells than from sensitive cells, and biological processes such as cell adhesion and angiogenesis were associated with the TAMR secretome. Galectin-3 binding protein (LGALS3BP) was one of the top 10 most highly secreted proteins in the TAMR secretome. The expression level of LGALS3BP was suppressed by estrogen signaling, which involves direct ERα binding to its promoter region. Secreted LGALS3BP in the TAMR secretome helped BC cells adhere to the extracellular matrix and promoted the tube formation of human umbilical vein endothelial cells. Compared with sensitive cells, xenograft animal experiments with MCF7/TAMR cells showed increased pulmonary metastasis, which completely disappeared in LGALS3BP-knockdown TAMR cells. Finally, higher levels of LGALS3BP were associated with poor prognosis in ER-positive BC patients treated with adjuvant tamoxifen in the clinic., Conclusion: TAMR secretome analysis identified secretory proteins, such as LGALS3BP, that are involved in biological processes closely related to metastasis. Secreted LGALS3BP from the TAMR cells promoted adhesion of the cells to the extracellular matrix and vasculature formation, which may support metastasis of TAMR cells., Competing Interests: Declarations. Ethics approval: The animal experiments were performed in accordance with the guidelines of the Seoul National University Animal Care and Use Committee (SNU-210906-2-3 and SNU-240124-3). Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

The regulation of cell physiology depends largely upon interactions of functionally distinct proteins and cellular components. These interactions may be transient or long-lived, but often affect protein motion. Measurement of protein dynamics within a cellular environment, particularly while perturbing protein function with small molecules, may enable dissection of key interactions and facilitate drug discovery; however, current approaches are limited by throughput with respect to data acquisition and analysis. As a result, studies using super-resolution imaging are typically drawing conclusions from tens of cells and a few experimental conditions tested. We addressed these limitations by developing a high-throughput single-molecule tracking (htSMT) platform for pharmacologic dissection of protein dynamics in living cells at an unprecedented scale (capable of imaging >10 6 cells/day and screening >10 4 compounds). We applied htSMT to measure the cellular dynamics of fluorescently tagged estrogen receptor (ER) and screened a diverse library to identify small molecules that perturbed ER function in real time. With this one experimental modality, we determined the potency, pathway selectivity, target engagement, and mechanism of action for identified hits. Kinetic htSMT experiments were capable of distinguishing between on-target and on-pathway modulators of ER signaling. Integrated pathway analysis recapitulated the network of known ER interaction partners and suggested potentially novel, kinase-mediated regulatory mechanisms. The sensitivity of htSMT revealed a new correlation between ER dynamics and the ability of ER antagonists to suppress cancer cell growth. Therefore, measuring protein motion at scale is a powerful method to investigate dynamic interactions among proteins and may facilitate the identification and characterization of novel therapeutics., Competing Interests: DM, HL, RT, SA, LA, RB, MB, HC, XD, KF, RG, EG, AH, AH, JH, SJ, RK, AK, RK, JL, KL, BM, PM, LM, SP, AS, CS, YT, DA, HB Employee of Eikon Therapeutics Inc, (© 2023, McSwiggen et al.)

HER2-positive/oestrogen receptor-positive (HER2+/ER+) represents a unique breast cancer subtype. The use of individual HER2- or ER-targeting agents can lead to the acquisition of therapeutic resistance due to compensatory receptor crosstalk. New drug combinations targeting HER2 and ER could improve outcomes for patients with HER2+/ER+ breast cancer. In this study, the pre-clinical rationale is explored for combining amcenestrant (Amc), a selective oestrogen receptor degrader (SERD), with HER2-targeted therapies including trastuzumab, trastuzumab-emtansine (T-DM1) and tyrosine kinase inhibitors (TKIs). The combination of Amc and anti-HER2 therapies was investigated in a panel of four HER2+/ER+ cell lines: BT-474, MDA-MB-361, EFM-192a and a trastuzumab-resistant variant BT-474-T. Proliferation (IC 50 and matrix combination assays) was determined using acid phosphatase assays. HER2/ER and intracellular signalling pathway protein levels/activity were investigated by western blot. Apoptosis was assessed using caspase 3/7 assays. Additivity and synergy were observed between Amc and the TKIs neratinib, lapatinib and tucatinib in all cell lines. Amc increased the anti-proliferative effect of trastuzumab in MDA-MB-361 and BT-474-T. Addition of Amc also increased anti-proliferative efficacy of T-DM1 in BT-474-T. TKI/Amc combinations reduced p-HER2 and ER levels and resulted in increased apoptosis. Higher ER expression in MDA-MB-361 and BT-474-T was associated with greater potential for synergy. In conclusion, the combination of Amc- and HER2-targeted treatments has potential as a therapeutic strategy for the treatment of HER2+/ER+ breast cancer and warrants further clinical investigation to validate safety and efficacy in patients.

Background/objectives: Both hyperandrogenism (HA) and vitamin D deficiency (VDD) can separately lead to impaired vascular reactivity and ovulatory dysfunction in fertile females. The aim was to examine the early interactions of these states in a rat model of PCOS., Methods: Four-week-old adolescent female rats were divided into four groups: vitamin D (VD)-supplemented ( n = 12); VD-supplemented and testosterone-treated ( n = 12); VDD- ( n = 11) and VDD-and-testosterone-treated ( n = 11). Animals underwent transdermal testosterone treatment for 8 weeks. Target VD levels were achieved with oral VD supplementation and a VD-free diet. Estrous cycles were followed by vaginal smear, and quantitative histomorphometric measurements of the ovaries were also taken. In the 8th week, testosterone- and estrogen-induced relaxation of coronary arterioles was examined with pressure angiography. Estrogen receptor (ER) density and oxidative and nitrative stress parameters (Poly-(ADP-Ribose)-Polymerase and 3-nitrotyrosine) in the vessel wall were investigated with immunohistochemistry., Results: VDD caused impaired estrous cycles, and testosterone caused anovulatory cycles (the cycles were stopped at the diestrous phase). VDD combined with testosterone treatment resulted in reduced testosterone and estrogen vasorelaxation, lower ER density, and higher oxidative and nitrative stress in the vessel wall., Conclusions: PCOS with vitamin D deficiency may be associated with increased oxidative-nitrative stress in coronary arterioles. This oxidative and nitrative stress, potentially caused by hyperandrogenism and/or vitamin D deficiency, could impair estrogen-induced relaxation of the coronary arterioles, possibly by decreasing NO bioavailability and disrupting the estrogen-induced relaxation pathway.

The efficacy of neoadjuvant therapy varies significantly with hormone receptor (HR) status for patients with human epidermal growth factor receptor 2 (HER2) positive breast cancer (BC). Despite extensive research on HER2 + BC, the optimal neoadjuvant strategy for HR+/HER2 + BC remains inconclusive. This study aimed to identify the optimal neoadjuvant regimen for HR+/HER2 + BC treatment. We conducted a systematic search for trials comparing neoadjuvant regimens for HR+/HER2 + BC and a network meta-analysis. Odds ratios for pathological complete response (pCR) and hazard ratios for event-free survival (EFS) were calculated. Treatment regimens were ranked using the surface under the cumulative ranking curve. 20 trials with 2809 patients were included. In pCR analysis, three neoadjuvant regimens sequentially ranked at the top, namely those comprising T-DM1, pertuzumab with trastuzumab, and tyrosine kinase inhibitor with trastuzumab, demonstrating significantly higher pCR rates than monotherapies. In EFS analysis, pertuzumab with trastuzumab ranked the first while T-DM1 containing regimen ranked the last. Anthracycline-free regimens showed a marginally higher pCR rate than anthracycline-containing regimens, while carboplatin-containing regimens demonstrated a numerically higher pCR rate than carboplatin-free regimens. Significant heterogeneity was observed in endocrine therapy analysis, which may be caused by different strategies for incorporating endocrine therapy. In conclusion, trastuzumab plus pertuzumab stands out as the optimal neoadjuvant HER2-targeting regimen for HR+/HER2 + BC Furthermore, anthracycline-free carboplatin-containing chemotherapy emerges as a promising combination treatment. Further investigation is required to clarify the role of endocrine therapy in HR+/HER2 + BC to guide its clinical application., Competing Interests: Declarations. Competing interests: Hao Tang, Yajing Feng and Xin Yu are current employees of Shanghai Roche Pharmaceuticals Ltd. The remaining authors have declared no conflicts of interest., (© 2024. The Author(s).)

The detection of Estrogen Receptor (ER), Progesterone Receptor (PR), and Human epidermal growth factor receptor 2 (HER-2) is important for the stratification of breast cancer and the selection of therapeutic modalities. This study aimed to determine the quantitative expression of ER, PR and HER-2 using Immunohistochemistry and their correlation with quantitative baseline Ct values measured using Quantitative Polymerase Chain Reaction (PCR). This study also assessed the use of fresh breast tissue biopsies preserved in RNAlater solution in the quantitative detection of these receptors using PCR technique. The study evaluated 20 matched formalin fixed paraffin embedded and RNAlater preserved samples for ER, PR, and HER-2 using IHC and quantitative PCR technique. One portion of the breast tissue biopsy was fixed immediately in 10% neutral buffered formalin and another was preserved in RNAlater. After the histological confirmation of breast cancer by the H&E technique, formalin fixed paraffin embedded tissues (FFPE)-positive cases were matched with their corresponding RNAlater samples for IHC and qPCR. The extracted RNA was quantified using Nanodrop technology, resulting into complementary DNA. ER and PR using IHC were expressed in 60% (n = 12) of the study samples and were negative in 40% (n = 8) of samples. HER-2 was negative in 70% (n = 14) of study samples, 25% (n = 5) positive, and 5% (n = 1) equivocal. With the quantitative expression of ER, PR, and HER-2 being reported in the IHC triple-negative breast cancer cases. The mean Ct values for the hormonal receptors correlated with what has been previously studied with ER at 19.631, PR at 25.410 and HER-2 at 25.695. There was no statistically significant difference between the mean Ct values of RNAlater and FFPE with their P-values being 0.9919, 0.0896 and < 0.0001 for ER, PR, and HER-2 respectively. P-values; 0.9919 and 0.0896 for ER and PR respectively being greater than 0.05 it's a borderline significance although HER-2 had a statistical significance. With a concordance in the detection of these breast cancer hormonal receptors, qPCR can be used in our setting considering the delays that may be associated in following the samples through IHC processing., Competing Interests: The authors have declared that no competing interets exist., (Copyright: © 2025 Wannume et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Purpose: In-vivo proton magnetic resonance spectroscopy (MRS) is a non-invasive method of analyzing choline metabolism that has been used to predict breast cancer prognosis. A strong choline peak may be a surrogate for aggressive tumor biology but its clinical relevance is unclear. The present study assessed whether total choline (tCho), as measured by proton MRS, can predict late recurrence in patients with hormone receptor (HR)-positive, HER2-negative early breast cancer., Methods: The study cohort included 261 HR+/HER2- breast cancer patients who underwent diagnostic single-voxel proton MRS (3.0T scanner) prior to first-line surgery from March 2011 to July 2014. The relationships between tCho compound peak integral (tChoi) values and others prognostic factor were analyzed, as were the effects of tChoi on 10-year disease-free survival (DFS) and overall survival (OS). The clinical significance of tChoi was also analyzed using Harrell's C-index., Results: Mean tChoi in HR+/HER2- study group was 15.47 and we set the cut-off for tChoi at 15 for survival analysis. 10-year DFS differed significantly between tChoi <15 and ≥15 (p = 0.017), with differences differing significantly for late (5-10 years; p = 0.02) but not early (0-5 years; p = 0.323) recurrence. Cox regression analysis showed that tChoi was significantly predictive of 10-year DFS (p = 0.046, OR 2.69) and tended to be predictive of late recurrence (HR 4.36, p = 0.066). Harrell's C-index showed that the Ki-67 index (AUC = 0.597) and lymphovascular invasion (AUC = 0.545) were also predictive of survival, with the addition of normalized tChoi improving the AUC to 0.622 (p = 0.014), indicating better predictive power., Conclusion: tChoi determined by in vivo MRS was predictive of prognosis in patients with HR+/HER2- early breast cancer. This parameter may serve as a valuable, non-invasive tool to predict prognosis when combined with other known prognostic factors., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2025 Kim et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objectives: To study the predictive role of tumor-associated neutrophils in early luminal HER2-negative breast cancer., Materials and Methods: This is a retrospective study conducted on 60 women cases aged from 31 to 79 years underwent surgery for luminal HER2-negative ductal breast cancer in tertiary care cancer centre. We first estimated basic morphological signs: tumor size, tumor grade (by Nottingham Histologic Score), tumor infiltrating lymphocytes (TILs), Lymphovascular invasion, hormonal receptors status, proliferative index, and regional lymph nodes metastasis. The expression of intratumoral neutrophils was studied by CD15 immunohistochemistry which was performed using tissue microarrays. The total number of intratumoral neutrophils, were counted in 5 high-power fields., Results: According to the Nottingham histologic score system, grade I cases were detected in 10 cases (16%), grade II in 34 cases (57%), and grade III in 16 cases (27%). Lymphovascular invasion was determined in 23 cases (38%), and perineural invasion in 14 cases (23%). Number of TILs varied from 0 to 14 (counted in 5 HPF) and averaged 4.2±0.5. Luminal A tumor phenotype was detected in 35 cases (58%), and luminal B HER2-negative in 25 cases (42%). Nineteen (32%) women had metastases in regional lymph nodes (N+). The number of tumor microenvironment neutrophils in luminal HER2-negative breast carcinomas ranged from 1 to 10 (counted in 5 HPF) with an average value of 2.7±0.4. High tumor-associated neutrophils concentration significantly correlated with tumor size (<5mm and >20mm) with p=0.05, high grade (p=0.01), high proliferative index ((r=0.67; p=0.05), TILs (p=0.05), Lymphovascular space invasion (p=0.01)and positive regional lymph nodes metastasis (p=0.001), but not perineural invasion (p=0.1) and also, did not correlate with the expression of estrogen (r=0.18) and progesterone (r=0.14) receptors., Conclusion: Tumor-associated neutrophils strongly predict a worse prognosis in early luminal HER2-negative breast cancer.

This review examines the complex interactions between estrogen receptors α and β (ERα and ERβ) and arginine vasopressin (AVP), delving into their significant roles in modulating empathy, a critical psychological component in human social dynamics. Empathy, integrating affective and cognitive elements, is anchored in neural regions like the amygdala and prefrontal cortex. ERα and ERβ, pivotal in estrogen regulation, influence neurotransmitter dynamics and neural network activities, crucial for empathic development. AVP, key in regulating water balance, blood pressure, and social behaviors, interplays with these receptors, profoundly impacting empathic responses. The study highlights that ERα predominantly enhances empathy, especially affective empathy, by stimulating AVP synthesis and release. In contrast, ERβ may diminish empathy in certain contexts by suppressing AVP expression and activity. The intricate interplay, homeostatic balance, and mutual conversion between ERα and ERβ in AVP regulation are identified as challenging yet crucial areas for future research. These findings provide essential insights into the neurobiological underpinnings of empathy, offering new avenues for therapeutic interventions in social cognitive disorders and emotional dysregulation., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The potential endocrine disruption activity of cyanotoxins, particularly their effects on estrogen and androgen receptors (ER, AR), remains poorly understood. In the present study, the potential agonistic/antagonistic estrogenic and androgenic activities of MC-LR and CYN have been determined for the first time with validated OECD Test Guidelines No. 455 and 458, respectively. The data show that only MC-LR demonstrated weak estrogenic agonistic effects (LogPC 10 value of -9.85 M), while both toxins displayed antagonistic effects on the ER, with LogIC 30 values of -4.4 and -6.4 for MC-LR and CYN, respectively. In addition, neither MC-LR nor CYN exhibited agonistic/antagonistic activities in AR. Docking studies revealed potential interactions between both toxins and AR, with CYN showing a higher predicted affinity for this receptor. In vivo studies, particularly those investigating androgen disruption, are warranted to confirm the endocrine disrupting potential of MC-LR and CYN., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Angeles Jos reports financial support was provided by SPANISH MINISTERIO DE CIENCIA E INNOVACIÓN. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The bromodomain and extraterminal domain (BET) family of proteins are critical chromatin readers that bind to acetylated histones through their bromodomains to activate transcription. Here, we reveal that bromodomain inhibition fails to repress oncogenic targets of estrogen receptor because of an intrinsic transcriptional mechanism. While bromodomains are necessary for the transcription of many genes, bromodomain-containing protein 4 (BRD4) binds to estrogen receptor binding sites and activates transcription of critical oncogenes such as MYC, independently of its bromodomains. BRD4 associates with the Mediator complex and disruption of Mediator reduces BRD4's enhancer occupancy. Profiling changes of the post-initiation RNA polymerase II (Pol II)-associated factors revealed that BET proteins regulate interactions between Pol II and elongation factors SPT5, SPT6 and the polymerase-associated factor 1 complex, which associate with BET proteins independently of their bromodomains and mediate their transcription elongation effect. Our findings highlight the importance of bromodomain-independent functions and interactions of BET proteins in the development of future therapeutic strategies., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Context.—: Laboratories performing predictive marker testing for breast carcinoma are encouraged to compare patient results to published benchmarks., Objective.—: To collect expression rates for estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor 2 (HER2) in invasive breast carcinoma from multiple laboratories., Design.—: Participants submitted data from up to 50 primary cases during the study period. Participants reported ER, PgR, and HER2 results in addition to demographic and histologic information. Participants also provided annual institution-level expression rates., Results.—: A total of 21 institutions submitted data for 687 cases. Aggregate positivity rates for ER and PgR were 85.6% and 75.1%, respectively. Receptor positivity rates were higher in well-differentiated (grade 1) tumors (ER, 97.4%; PgR, 88.0%) compared with moderately differentiated (grade 2) tumors (ER, 92.4%; PgR, 84.0%) and poorly differentiated (grade 3) tumors (ER, 61.8%; PgR, 48.0%). Expression rates were higher in postmenopausal women (ER, 87.2%) than premenopausal women (ER, 79.6%) and higher in lobular carcinomas (ER, 98.7%; PgR, 85.3%) than ductal carcinomas (ER, 84.1%; PgR, 74.5%). The aggregate HER2 positivity (score 3+) rate was 9.0%. The aggregate HER2 equivocal (score 2+) rate was 14.5%. Of 81 equivocal (score 2+) cases, 70 (86.4%) were nonamplified., Conclusions.—: The data from this study provide multi-institutional benchmark data to assist laboratories performing periodic comparisons as part of a quality management program. Overall expression rates were generally similar to those of other published reports, with the exception of the ER-negative and HER2-positive rates, both of which were somewhat lower., Competing Interests: The authors have no relevant financial interest in the products or companies described in this article., (© 2025 College of American Pathologists.)

Purpose: This Phase II trial was objected to evaluate the efficacy and safety of adding fulvestrant to neoadjuvant chemotherapy in patients with estrogen receptor (ER)+/human epidermal growth factor receptor 2 (HER2)- locally advanced breast cancer (LABC). Additionally, the study aimed to investigate the association of 16α-18F-fluoro-17β-fluoroestradiol (18F-FES) positron emission tomography (PET)-computed tomography (CT) and metabolites with efficacy., Materials and Methods: Fulvestrant and EC-T regimen were given to ER+/HER2- LABC patients before surgery. At baseline, patients received 18F-FES PET-CT scan, and plasma samples were taken for liquid chromatography-mass spectrometry analysis. The primary endpoint was objective response rate (ORR). Secondary endpoints included total pathologic complete response (tpCR) and safety., Results: Among the 36 patients enrolled, the ORR was 86.1%, the tpCR rate was 8.3%. The incidence of grade ≥ 3 treatment-emergent adverse events was 22%. The decrease in ER value in sensitive patients was larger than that in non-sensitive patients, as was Ki-67 (p < 0.05). The maximum standardized uptake value, mean standardized uptake values, total lesion ER expression of 18F-FES PET-CT in sensitive patients were significantly higher than those in non-sensitive patients (p < 0.05). Moreover, these parameters were significantly correlated with Miller and Payne grade and the change in ER expression before and after treatment (p < 0.05). Thirteen differential expressed metabolites were identified, which were markedly enriched in 19 metabolic pathways., Conclusion: This regimen demonstrated acceptable toxicity and encouraging antitumor efficacy. 18F-FES PET-CT might serve as a tool to predict the effectiveness of this therapy. Altered metabolites or metabolic pathways might be associated with treatment response.

Background: Breast cancer (BC) is a significant burden on healthcare systems, especially in low- and middle-income countries where access to diagnosis and treatment is challenging., Objectives: The purpose of this study was to assess the diagnostic accuracy and cost using tissue microarray (TMA) instead of traditional immunohistochemical (IHC) evaluation for estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor 2 (HER2), and the proliferation marker Ki-67 and BC subtyping within the Brazilian public health system., Design: This is a retrospective cohort study comparing TMA slides with traditional whole-slide evaluation for IHC markers in 242 BC cases., Methods: We used formalin-fixed tissue blocks for TMA assembly. Clinical data and IHC scores for ER, PR, HER2, and Ki-67 were obtained from pathology reports. Cohen's kappa ( k ) was used to assess TMA performance., Results: BC samples were distributed in 10 TMAs and 968 cores were scored (242 BC cases × 4 markers). In 97% of these, TMA reached high quality to adequate IHC scoring with minimal technical issues. Inter-examiner agreement was almost perfect for all markers (ranging from 0.85 for HER2 to 0.91 for ER, p  < 0.001). The intratumoral heterogeneity ranged from almost perfect agreement for ER and HER2 to moderate to substantial for PR and Ki-67. TMA offers substantial time and cost savings, with an approximately 11-fold reduction compared to traditional methods. The concordance between TMA and original reports was almost perfect, with 93% overall agreement ( k  = 0.81, p  < 0.001). However, TMA performance varied between markers, with intratumoral heterogeneity significantly impacting discordant results, particularly for Ki-67 and HER2. This ultimately affected the accuracy of BC subtyping. TMA performed well in identifying luminal A and triple-negative cases, but misclassification was common for luminal B and HER2-positive cases., Conclusion: TMA offers accurate and lower-cost results in the individualized IHC assessment of BC markers. However, we do not recommend the use of TMA in the subtyping of BC, where analysis of the whole section remains necessary for more accurate results. We advocate more studies using the TMA approach in the Brazilian public health system to advance women's health care.

Background/aim: G protein-coupled estrogen receptor 1 (GPER1) appears to play a tumor-suppressive role in cervical squamous cell carcinoma (CSCC)GPER1 suppression leads to significantly increased expression of serpin family E member 1 (SERPINE1)/protein plasminogen activator inhibitor type 1 (PAI-1). The question arises, what role does SERPINE1/PAI-1 play in GPER1-dependent tumorigenic potential of CSCC., Materials and Methods: SiHa and C33A CSCC cells were treated with GPER1 agonist G1 or antagonist G36. SERPINE1/PAI-1 expression was suppressed by RNAi and success was confirmed by RT-qPCR. Protein expression of PAI-1 was quantified by Western blot. Viability was analyzed using resazurin assay, while migration was investigated using gap closure. Colony and tumor sphere formation were used to test clonogenicity., Results: After G1 treatment, viability of SiHa and C33A cells remained unchanged. Cell migration was dose-dependently reduced. SiHa and C33A cells formed significantly fewer and smaller colonies as well as spheroids. Furthermore, treatment with G1 led to decreased expression of SERPINE1/PAI-1, while blockade of GPER1 with G36 resulted in significantly increased SERPINE1/PAI-1 expression. After suppression of SERPINE1/PAI-1 in SiHa cells using RNAi, cell viability remained unaffected; however, significantly smaller colonies were formed, and fewer and smaller spheroids were developed. Cell migration remained unaffected., Conclusion: Activation of GPER1 reduces clonogenicity and migration of CSCC cells and suppresses expression of SERPINE1/PAI-1. Suppression of SERPINE1/PAI-1 in CSCC cells reduces tumorigenic potential. GPER1 may be a suitable target for suppression of SERPINE1/PAI-1 in CSCC. However, SERPINE1/PAI-1 does not appear to be the decisive factor for GPER1-regulated cell migration., (Copyright © 2025, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

CDK4/6 inhibitors such as palbociclib block cell cycle progression and improve outcomes for many ER+/HER2- breast cancer patients. Unfortunately, many patients are initially resistant to the drug or develop resistance over time in part due to heterogeneity among individual tumor cells. To better understand these mechanisms of resistance, we used multiplex, single-cell imaging to profile cell cycle proteins in ER+ breast tumor cells under increasing palbociclib concentrations. We then applied spherical principal component analysis (SPCA), a dimensionality reduction method that leverages the inherently cyclical nature of the high-dimensional imaging data, to look for changes in cell cycle behavior in resistant cells. SPCA characterizes data as a hypersphere and provides a framework for visualizing and quantifying differences in cell cycles across treatment-induced perturbations. The hypersphere representations revealed shifts in the mean cell state and population heterogeneity. SPCA validated expected trends of CDK4/6 inhibitor response such as decreased expression of proliferation markers (Ki67, pRB), but also revealed potential mechanisms of resistance including increased expression of cyclin D1 and CDK2. Understanding the molecular mechanisms that allow treated tumor cells to evade arrest is critical for identifying targets of future therapies. Ultimately, we seek to further SPCA as a tool of precision medicine, targeting treatments by individual tumors, and extending this computational framework to interpret other cyclical biological processes represented by high-dimensional data.

Endocrine Disruptor Compounds (EDCs) in the aquatic environment have acquired pronounced relevance due to their toxic effect on the aquatic flora and fauna. Xenoestrogens are EDCs that possess estrogenic activity and, thus, disrupt normal estrogen signaling, affecting different functions, such as immune system processes. Two relevant xenoestrogens discarded into fresh and seawater are 4-nonylphenol (NP) and 17⍺-Ethynyl Estradiol (EE2). Considering that the piscicultures of Salmo salar can be located at sites of potential exposure to xenoestrogen-containing effluxes, it is crucial to understand the effect of xenoestrogens on the immune response and its possible molecular mechanism in this species. Our studies reveal an increase in the expression of the receptor era and erb at early times of exposure, a disrupted expression of pro-inflammatory cytokines (il1b and tnfa), an upregulation of ssa-miR-146a-5p, ssa-miR-125 b-5p, and downregulation of ssa-miR-145-5p in ASK cells exposed to estrogen and xenoestrogen, could potentially lead to new strategies for mitigating the effects of xenoestrogens on Salmo salar immune response., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Estrogen receptors (ERs), comprising ER α and ER β, are crucial for regulating cell growth and differentiation via homo- and hetero-dimer formation. However, accurately detecting ER dimerization with precise spatiotemporal resolution remains a significant challenge. In this study, fluorescence resonance energy transfer-based biosensors to monitor ER dynamics in real-time, are developed and optimized. This approach involves comprehensive structural analysis, linker comparison, and the selection of optimal fluorescent protein pairs, resulting in three distinct biosensors capable of detecting all ER homo- and hetero-dimerizations within the nucleus. These biosensors are utilized to reveal interactions between ER α/β and calmodulin during dimer formation. Furthermore, by leveraging the ligand-binding domain (LBD) of ER β, ER ββ LBD biosensor is designed for real-time analysis of ER ββ homodimerization in the cytoplasm, enhancing the ability to screen ER dimerization-related drugs. Additionally, we developed a novel ER ββ translocation biosensor, which enables real-time observation of ER ββ translocation to the nucleus-a capability previously unavailable, is developed. This spatiotemporal analysis demonstrates the relevance of ER translocation in response to drug binding efficacy and extracellular matrix changes. Our biosensors offer transformative tools for studying ER dynamics, providing valuable insights for drug screening and the investigation of ER-related cellular processes., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Background: The Hormonal Bone Effects (HOBOE) study tested whether adjuvant triptorelin plus either letrozole (L) or zoledronic acid (Z) plus L (ZL) was more effective than tamoxifen (T) in premenopausal patients with hormone receptor-positive (HR+) early breast cancer (BC). Here we report the long-term follow-up analysis., Patients and Methods: HOBOE (ClinicalTrials.gov number NCT00412022) is an open-label, three-arm, randomised, phase III trial that involved 16 centres in Italy. One thousand and sixty-five premenopausal patients with HR+ early BC receiving triptorelin were randomly assigned (1 : 1 : 1) to adjuvant T, L or ZL for 5 years. Cancer recurrence, second breast or non-breast cancer and death were considered events for the intention-to-treat disease-free survival (DFS) analysis., Results: As of 24 October 2024 at a median follow-up of 9.2 years, 199 DFS events and 79 deaths were reported. Both ZL and L improved DFS over T, with a hazard ratio (HR) of 0.58 [95% confidence interval (CI) 0.41-0.82; P = 0.002] for ZL versus T and 0.69 (95% CI 0.49-0.97, P = 0.030) for L versus T. No statistically significant difference in OS was reported (global log-rank P = 0.103). The previously reported statistically significant interaction with human epidermal growth factor receptor 2 (HER2) status was confirmed for ZL versus T comparison (P = 0.007)., Conclusion: In this updated analysis, L plus triptorelin, with or without Z, demonstrated a statistically significant DFS improvement over T plus triptorelin for the adjuvant treatment of early BC in premenopausal patients., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) breast cancer is the most common subtype, representing over two-thirds of new diagnoses. Adjuvant therapy, which encompasses various medications and treatment durations, is the standard approach for managing early stage HR+ HER2- breast cancer. Optimizing treatment is essential to minimize unnecessary side effects while addressing the biological variability inherent in HR+/HER2- breast cancers. Incorporating biological biomarkers into treatment decisions, alongside traditional clinical factors, is vital. Gene expression assays can identify patients unlikely to benefit from adjuvant chemotherapy, thereby refining treatment strategies and improving risk assessment. This paper reviews evidence for several genomic tests, including Oncotype DX, MammaPrint, Breast Cancer Index, RucurIndex, and EndoPredict, which assist in tailoring adjuvant therapy. Additionally, we explore the role of liquid biopsies in personalizing treatment, emphasizing the importance of considering late relapse risks and potential benefits of extended systemic therapy for HR+/HER2- breast cancer patients.

Macrophages are pivotal in driving breast tumor development, progression, and resistance to treatment, particularly in estrogen receptor-positive (ER+) tumors, where they infiltrate the tumor microenvironment (TME) influenced by cancer cell-secreted factors. By analyzing single-cell RNA sequencing data from 25 ER+ tumors, we elucidated interactions between cancer cells and macrophages, correlating macrophage density with epithelial cancer cell density. We identified that S100A11, a previously unexplored factor in macrophage-cancer crosstalk, predicts high macrophage density and poor outcomes in ER+ tumors. We found that recombinant S100A11 enhances macrophage infiltration and migration in a dose-dependent manner. Additionally, in a 3D matrix using a panel of three ER+ breast cancer cell lines, we showed that secreted S100A11 levels from cancer cells were associated with increased monocyte infiltration that subsequently differentiation toward macrophages. Genetic silencing of S100A11 in the S100A11-high T47D cancer cells reduced monocyte infiltration, consistent with results using a S100A11 blocking antibody in T47D cancer cells and in a clinically relevant patient-derived organoid model. Phenotypic analysis of macrophages cocultured with T47D cancer cells following S100A11 knockdown revealed lower expression of the immunosuppressive marker CD206, further underscoring the role of S100A11 as a paracrine regulator of pro-tumorigenic cancer-macrophage crosstalk. This study offers novel insights into the interplay between macrophages and cancer cells in ER+ breast tumors, highlighting S100A11 as a potential therapeutic target to modulate the macrophage-rich tumor microenvironment.

The standard treatment for hormone receptor-positive breast cancer in good general condition is curative surgery followed by endocrine therapy. However, for older patients, endocrine therapy alone is sometimes chosen instead of curative surgery due to health conditions or personal preference, though this is not yet a standard approach. It is crucial to develop elderly-specific treatment strategies, potentially establishing endocrine therapy alone as a standard option. While endocrine therapy is generally effective, some patients show disease progression from the beginning due to de novo resistance. Hence, identifying such tumors is essential to determine who may benefit from endocrine therapy alone. Fifty-one patients aged over 70 years with estrogen receptor-positive and human epidermal growth factor receptor 2-negative invasive breast cancer who were treated with endocrine therapy instead of curative surgery were retrospectively investigated. Genes possibly related to de novo resistance to endocrine therapy were analyzed using a gene expression panel. Of the 51 patients, three patients showed progressive disease (PD) within 6 months of starting endocrine therapy. Gene expression analysis revealed that some genes, including those related to the cell cycle, such as CDKN3, were expressed at higher levels in the PD group compared with the non-PD group. Among these, CDKN3 retained significantly high expression in the PD group, even after analyzing more samples (log2 fold change, 1.99; P = 0.005). Public mRNA microarray data analysis revealed that patients with high CDKN3 tumors had worse outcomes. We identified several genes possibly involved in the de novo resistance to endocrine therapy. Our data indicate CDKN3 to be a predictive marker for de novo endocrine therapy resistance in older patients with breast cancer. We hope that our data will contribute to further research to establish tailored treatments for elderly breast cancer patients., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethical approval and consent to participate: This study was approved by the institutional review board of our hospital (no: H19-0289). The institutional review board waived the need for written informed consent due to the retrospective nature of the study. Patients could see the research plan on the hospital website and were offered the choice to opt out of the study at any time. This study was performed in accordance with the Declaration of Helsinki., (© 2024. The Author(s).)

Ovarian cancer remains one of the leading causes of cancer-related deaths in women. There are several processes that are described to have a causal relationship in ovarian cancer development, progression, and metastasis formation, that occur both at the genetic and epigenetic level. One of the mechanisms involved in its pathogenesis and progression is estrogen signaling. Estrogen receptors (ER) α, ERβ, and G-protein coupled estrogen receptor 1 (GPER1), in concert with various coregulators and pioneer transcription factors, mediate the effects of estrogens primarily by the transcriptional regulation of estrogen responsive genes, thereby exerting pleiotropic effects including the regulation of cellular proliferation and apoptosis. The expression and activity of estrogen receptors and their coregulators have been demonstrated to be regulated by epigenetic mechanisms like histone modifications and DNA methylation. Here, we intend to summarize and to provide an update on the current understanding of epigenetic mechanisms regulating estrogen signaling and their role in ovarian cancer. For this purpose, we reviewed publications on this topic listed in the PubMed database. Finally, we assess to which extent drugs acting on the epigenetic level might be suitable for the treatment of ovarian cancer.

HR + /HER2-low breast cancer is a significant subgroup of conventional HR + /HER2-negative breast cancer, and combination of CDK4/6 inhibitor and endocrine therapy is the standard first-line and second-line treatments for advanced HR + /HER2-low breast cancer. Nevertheless, it remains uncertain whether HER2 signaling affects the effectiveness of CDK4/6 inhibitor administered in combination with endocrine therapy for HR + /HER2-low breast cancer and suitable intervention measures. This study revealed poor efficacy for CDK4/6 inhibitor combined with endocrine therapy for HR + /HER2-low breast cancer in vitro and in vivo models. Secondly, suppression of HER2 gene expression in HR + /HER2-low breast cancer cells resulted in significantly improved efficacy for CDK4/6 inhibitor combined with endocrine therapy. Furthermore, the anti-HER inhibitor neratinib was administered to enhance the effectiveness of CDK4/6 inhibitor combined with endocrine therapy in HR + /HER2-low breast cancer by inhibiting the HER2 pathway and lowering HER2 mRNA expression. Strikingly, neratinib reversed the efficacy of CDK4/6 inhibitor and endocrine therapy by reducing HER2 mRNA stability in HR + /HER2-low breast cancer through the interaction of HER2 3'-UTR region with hsa-miR-23a-5p. Even after reducing neratinib dosage to the standard 1/2 dose (20 mg/kg), it remained highly effective and well-tolerated. This study provides a viable and well-tolerated triple combination therapy for clinical HR + /HER2-low breast cancer., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethical approval: This study was conducted according to ARRIVE guidelines 2.0. Liushan Chen, Lingling Ye, and Yuqi Liang are co-first authors. Yingchao Wu, Qianqian Guo, and Qianjun Chen are co-corresponding authors., (© 2024. The Author(s).)

Breast cancer remains one of the most prevalent and lethal malignancies in women, particularly the estrogen receptor-positive (ER+) subtype, which accounts for approximately 70% of cases. Traditional endocrine therapies, including aromatase inhibitors, selective estrogen receptor degraders/antagonists (SERDs), and selective estrogen receptor modulators (SERMs), have improved outcomes for metastatic ER+ breast cancer. However, resistance to these agents presents a significant challenge. This study explores a novel therapeutic strategy involving the simultaneous inhibition of the estrogen receptor (ER) and the chaperone protein Hsp90, which is crucial for the stabilization of various oncoproteins, including ER itself. We employed a hybrid, hierarchical in silico virtual screening approach to identify new dual ER/Hsp90 inhibitors, utilizing the Biotarget Predictor Tool (BPT) for efficient multitarget screening of a large compound library. Subsequent structure-based studies, including molecular docking analyses, were conducted to further evaluate the interaction of the top candidates with both ER and Hsp90. Supporting this, molecular dynamics simulations demonstrate the high stability of the multitarget inhibitor 755435 in complex with ER and Hsp90. Our findings suggest that several small molecules, particularly compound 755435 , exhibit promising potential as dual inhibitors, representing a new avenue to overcome resistance in ER+ breast cancer.

We aim to investigate whether chemical inhibition of NRF2 transcriptional activity (TA) influences distal colon contractions, particularly in an age-dependent manner in females, and whether it impacts oestrogen receptor signalling in female mice. This study was performed on 3 and 6-month-old female mice treated with ML385 (30 mg/kg) or a vehicle for 7 days (i.p.). The colon functionality was verified with a colon bead expulsion test; serum samples were collected for oestradiol levels, and colon samples were stored for various histological analyses. The results show that the seven-day treatment of ML385 significantly downregulated TA ( p < 0.05) and impacted its contractility. Additionally, young females treated with ML385 exhibited an increase in goblet cell number and significantly increased ERα, but not ERβ, especially in older mice. It is worth noting that the basal level of the membrane oestrogen receptor GPR30 was higher in older mice within the epithelial layer, and ML385 treatment led to a downregulation of GPR30 in 6-month-old mice. In summary, ML385 decreases NRF2 TA in the colon and impacts its contractility and goblet cell numbers. Additionally, NRF2 TA influences the expression of oestrogen receptors in the colons of female mice.

Background: Myocarditis is an inflammation of the heart muscle most often caused by viral infections. Sex differences in the immune response during myocarditis have been well described but upstream mechanisms in the heart that might influence sex differences in disease are not completely understood., Methods: Male and female BALB/c wild type mice received an intraperitoneal injection of heart-passaged coxsackievirus B3 (CVB3) or vehicle control. Bulk-tissue RNA-sequencing was conducted to better understand sex differences in CVB3 myocarditis. We performed enrichment analysis and functional validation to understand sex differences in the transcriptional landscape of myocarditis and identify factors that might drive sex differences in myocarditis., Results: As expected, the hearts of male and female mice with myocarditis were significantly enriched for pathways related to an innate and adaptive immune response compared to uninfected controls. Unique to this study, we found that males were enriched for inflammatory pathways and gene changes that suggested worse mitochondrial electron transport function while females were enriched for pathways related to mitochondrial homeostasis. Mitochondria isolated from the heart of males were confirmed to have worse mitochondrial respiration than females during myocarditis. Unbiased TRANSFAC analysis identified estrogen-related receptor alpha (ERRα) as a transcription factor that may mediate sex differences in mitochondrial function during myocarditis. Transcript and protein levels of ERRα were confirmed as elevated in females with myocarditis compared to males. Differential binding analysis from chromatin immunoprecipitation (ChIP) sequencing confirmed that ERRα bound highly to select predicted respiratory chain genes in females more than males during myocarditis., Conclusions: Females with viral myocarditis regulate mitochondrial homeostasis by upregulating master regulators of mitochondrial transcription including ERRα., Competing Interests: Declarations. Ethics approval and consent to participate: Mice were used in accordance with the recommendations in the Guide for the Care and Use the Laboratory Animals of the National Institutes of Health (NIH) and approval obtained from the Animal Care and Use Committee at Mayo Clinic Florida for all procedures (IACUC# A00003984). Mice were maintained under pathogen-free conditions in the animal facility at Mayo Clinic Florida and mice were sacrificed according to the Guide for the Care and Use of Laboratory Animals of the NIH. Consent for publication: Not applicable. Competing interests: The authors declare that they have no competing interests., (© 2024. The Author(s).)

Estrogen (E2) deficiency is a risk factor for cardiovascular disease (CVD), however, the exact mechanism for the E2 protective effect on CVD remains unclear. This study aimed to investigate the estrogen receptor (ER) and non-receptor mediated effects of E2 treatment on the cardiac expression of adenosine monophosphate-dependent protein kinase (AMPK), autophagic, mitophagy and mitochondrial homeostasis-regulating genes in ovariectomized (OVX) rats. Female rats were divided into two main groups; sham and bilaterally OVX rats, then each group was subdivided into four subgroups according to treatment; untreated, subcutaneously treated with E2 (30 μg/kg), or Fulvestrant (F) (5 mg/Kg), or a combination of both drugs for 28 days. The OVX rats or F-treated sham rats showed dyslipidemia, and marked disturbances in parameters of AMPK signaling, autophagy, mitophagy, mitochondrial fission, fusion and biogenesis. E2 administration to OVX or F-treated sham rats has corrected the disturbed lipid and cardiac profiles, increased AMPK, and restored the balance of cardiac autophagy, mitophagy, and mitochondrial dynamics and homeostasis. Most of these effects in OVX rats were blocked by the ER antagonist (F). Estrogen treatment has cardioprotective effects in OVX females through modulating cardiac mitochondrial homeostasis, mitophagy and autophagy and restoring the AMPK signaling pathway. As witnessed by Fulvestrant, these effects suggest the main role of ER-mediated signaling in regulating mitophagy and plasma and cardiac lipids along with the existence of a post-translational control mechanism or the involvement of estrogenic non-receptor pathway controlling the postmenopausal cardiac mitochondrial energy production machinery that needs further investigation., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Gowayed et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: The HOXB13/IL17RB gene expression biomarker has been shown to predict response to adjuvant and extended endocrine therapy in patients with early-stage ER+ HER2- breast tumors. HOXB13 gene expression is the primary determinant driving the prognostic and endocrine treatment-predictive performance of the biomarker. Currently, there is limited data on HOXB13 expression in HER2+ and ER- breast cancers. Herein, we studied the expression of HOXB13 in large cohorts of HER2+ and ER- breast cancers., Methods: We investigated gene expression, genomic copy number, mutational signatures, and clinical outcome data in the TGGA and METABRIC breast cancer cohorts. Genomic-based gene amplification data was validated with tri-colored fluorescence in situ hybridization., Results: In the TCGA breast cancer cohort, HOXB13 gene expression was significantly higher in HER2+ versus HER2- breast cancers, and its expression was also significantly higher in the ER- versus ER+ breast cancers. HOXB13 is frequently co-gained or co-amplified with ERBB2. Joint copy gains of HOXB13 and ERBB2 occurred with low-level co-gains or high-level co-amplifications (co-amp), the latter of which is associated with an interstitial loss that includes the tumor suppressor BRCA1. ERBB2/HOXB13 co-amp tumors with interstitial BRCA1 loss exhibit a mutational signature associated with APOBEC deaminase activity and copy number signatures associated with chromothripsis and genomic instability. Among ERBB2-amplified tumors of different tissue origins, ERBB2/HOXB13 co-amp with a BRCA1 loss appeared to be enriched in breast cancer compared to other tumor types. Lastly, patients with ERBB2/HOXB13 co-amplified and BRCA1 lost tumors displayed a significantly shorter progression-free survival (PFS) than those with ERBB2-only amplifications. The difference in PFS was restricted to the ER- subset patients and this difference in PFS was not solely driven by HOXB13 gene expression., Conclusions: HOXB13 is frequently co-gained with ERBB2 at both low-copy number level or as complex high-level amplification with relative BRCA1 loss. ERBB2/HOXB13 amplified, BRCA1-lost tumors are strongly enriched in breast cancer, and patients with such breast tumors experience a shortened PFS., Competing Interests: Declarations. Ethical approval: This study was approved by the Massachusetts General Hospital IRB under protocol 2002-P002059/MGH. Consent for publication: not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Resistance to endocrine therapies (ET) is common in estrogen receptor (ER)-positive breast cancer, and most relapsed patients die with ET-resistant disease. Although genetic mutations provide explanations for some relapses, mechanisms of resistance remain undefined in many cases. Drug-induced epigenetic reprogramming has been shown to provide possible routes to resistance. By analyzing histone H3 lysine 27 acetylation profiles and transcriptional reprogramming in models of ET resistance, we discovered that selective ER degraders, such as fulvestrant, promote expression of vestigial-like 1 (VGLL1), a coactivator for TEF-1 and AbaA domain (TEAD) transcription factors. VGLL1, acting via TEADs, promoted the expression of genes that drive the growth of fulvestrant-resistant breast cancer cells. Pharmacological disruption of VGLL1-TEAD4 interaction inhibited VGLL1/TEAD-induced transcriptional programs to prevent the growth of resistant cells. EGFR was among the VGLL1/TEAD-regulated genes, and VGLL1-directed EGFR upregulation sensitized fulvestrant-resistant breast cancer cells to EGFR inhibitors. Taken together, these findings identify VGLL1 as a transcriptional driver in ET resistance and advance therapeutic possibilities for relapsed ER+ breast cancer patients. Significance: Transcriptional reprogramming mediated by the upregulation of the TEAD coactivator VGLL1 confers resistance to estrogen receptor degraders in breast cancer but provides alternative therapeutic options for this clinically important patient group., (©2024 American Association for Cancer Research.)