Exploring the effectiveness of molecular subtypes, biomarkers, and genetic variations as first-line treatment predictors in Asian breast cancer patients: a systematic review and meta-analysis.

BACKGROUND: Breast cancer incidence has been on the rise significantly in the Asian population, occurring at an earlier age and a later stage. The potential predictive value of molecular subtypes, biomarkers, and genetic variations has not been deeply explored in the Asian population. This study evaluated the effect of molecular subtype classification and the presence or absence of biomarkers and genetic variations on pathological complete response (pCR) after neoadjuvant treatment in Asian breast cancer patients. METHODS: A systematic search was conducted in MEDLINE (PubMed), Science Direct, Scopus, and Cochrane Library databases. Studies were selected if they included Asian breast cancer patients treated with neoadjuvant chemotherapy and contained data for qualitative or quantitative analyses. The quality of the included studies was assessed using the Newcastle Ottawa Scale. Following the random effects model, pooled odds ratios or hazard ratios with 95% confidence intervals for pCR were analysed using Review Manager Software. Heterogeneity between studies was assessed using Cochran's Q-test and I2 test statistics. RESULTS: In total, 19,708 Asian breast cancer patients were pooled from 101 studies. In the neoadjuvant setting, taxane-anthracycline (TA) chemotherapy showed better pCR outcomes in triple-negative breast cancer (TNBC) (p<0.0001) and human epidermal growth factor receptor 2 enriched (HER2E) (p<0.0001) than luminal breast cancer patients. Similarly, taxane-platinum (TP) chemotherapy also showed better pCR outcomes in TNBC (p<0.0001) and HER2E (p<0.0001). Oestrogen receptor (ER)-negative, progesterone receptor (PR)-negative, HER2-positive and high Ki-67 were significantly associated with better pCR outcomes when treated with either TA or TP. Asian breast cancer patients harbouring wildtype PIK3CA were significantly associated with better pCR outcomes when treated with TA in the neoadjuvant setting (p=0.001). CONCLUSIONS: In the neoadjuvant setting, molecular subtypes (HER2E and TNBC), biomarkers (ER, PR, HER2, HR, Ki-67, nm23-H1, CK5/6, and Tau), and gene (PIK3CA) are associated with increased pCR rates in Asian breast cancer patients. Hence, they could be further explored for their possible role in first-line treatment response, which can be utilised to treat breast cancer more efficiently in the Asian population. However, it needs to be further validated with additional powered studies. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42021246295.

Estrogen receptor activation remodels TEAD1 gene expression to alleviate hepatic steatosis.

Sex-based differences in obesity-related hepatic malignancies suggest the protective roles of estrogen. Using a preclinical model, we dissected estrogen receptor (ER) isoform-driven molecular responses in high-fat diet (HFD)-induced liver diseases of male and female mice treated with or without an estrogen agonist by integrating liver multi-omics data. We found that selective ER activation recovers HFD-induced molecular and physiological liver phenotypes. HFD and systemic ER activation altered core liver pathways, beyond lipid metabolism, that are consistent between mice and primates. By including patient cohort data, we uncovered that ER-regulated enhancers govern central regulatory and metabolic genes with clinical significance in metabolic dysfunction-associated steatotic liver disease (MASLD) patients, including the transcription factor TEAD1. TEAD1 expression increased in MASLD patients, and its downregulation by short interfering RNA reduced intracellular lipid content. Subsequent TEAD small molecule inhibition improved steatosis in primary human hepatocyte spheroids by suppressing lipogenic pathways. Thus, TEAD1 emerged as a new therapeutic candidate whose inhibition ameliorates hepatic steatosis.

Women's Health Update: Growing Role of PET for Patients with Breast Cancer.

Positron Emission Tomography (PET) has been growing in usage for patients with breast cancer, due to an increased number of FDA-approved PET radiotracers pertinent to patients with breast cancer as well as increased prospective evidence for the value of these agents. The leading PET radiotracer for patients with breast cancer is 18F-fluorodeoxyglucose (18F-FDG), which measures glucose metabolism. There is prospective evidence for the use of 18F-FDG PET in systemic staging of newly diagnosed locally advanced breast cancer (stages IIB-IIIC), monitoring breast cancer treatment response, and detecting breast cancer recurrence, particularly in no special type (NST) breast cancer. 16α-18F-fluoro-17ß-Fluoroestradiol (18F-FES) is a radiolabeled estrogen which evaluates estrogen receptor (ER) accessible for estrogen binding. There is prospective evidence supporting 18F-FES PET as a predictive biomarker for selecting patients with metastatic breast cancer for endocrine therapies. 18F-FES PET has also been shown to be valuable in the evaluation of ER status of lesions which are difficult to biopsy, for evaluation of ER status in lesions that are equivocal on other imaging modalities, and for selecting optimal dosage of novel ER-targeted systemic therapies in early clinical trials. Multiple investigators have suggested 18F-FES PET will have an increasing role for patients with invasive lobular breast cancer (ILC), which is less optimally evaluated by 18F-FDG PET. Sodium 18F-Fluoride (18F-NaF) evaluates bone turnover and has been effective in evaluation of malignancies which commonly metastasize to bone. In patients with metastatic breast cancer, 18F-NaF PET/CT has demonstrated superior sensitivity for osseous metastases than 99mTc-MDP or CT. In addition to these three FDA-approved PET radiotracers, there are multiple novel radiotracers currently in clinical trials with potential to further increase PET usage for patients with breast cancer.

Utilization and outcomes of the 21-gene recurrence score in de novo metastatic breast cancer.

BACKGROUND: Limited data exist regarding the utility and validity of the 21-gene recurrence score (RS) in patients with de novo metastatic breast cancer (dnMBC). This study aimed to investigate the practice patterns as well as associated survival outcomes based on 21-gene RS in dnMBC. RESEARCH DESIGN AND METHODS: The Surveillance, Epidemiology, and End Results Oncotype database was queried for women with hormone receptor-positive and Her2-negative dnMBC. RESULTS: A total of 153 patients were identified, including 62.7% and 37.3% of patients who had RS < 26 and ≥ 26, respectively. Patients with RS ≥ 26 were more likely to receive chemotherapy compared to those with RS < 26 (61.4% vs. 28.1%, p < 0.001). Patients with RS ≥ 26 had an inferior breast cancer-specific survival (BCSS) (2-year BCSS: 84.3% vs. 89.5, p = 0.067) and overall survival (OS) compared to those with RS < 26 (2-year OS: 76.9% vs. 87.4%, p = 0.018). The multivariate Cox proportional hazard models showed that those with RS ≥ 26 had a significantly inferior BCSS (hazard ratio [HR] 2.251, 95% confidence interval [CI] 1.056-4.799, p = 0.036) and OS (HR 2.151, 95%CI 1.123-4.120, p = 0.021) compared to those with RS < 26. CONCLUSIONS: The 21-gene RS assay is an important prognostic factor in patients with dnMBC.

Breast density reduction as a predictor for prognosis in premenopausal women with estrogen receptor-positive breast cancer: an exploratory analysis of the updated ASTRRA study.

BACKGROUND: While the relationship between mammographic breast density reduction (MDR) and endocrine therapy efficacy has been reported in estrogen receptor (ER)-positive breast cancer, it is still unclear in premenopausal women, especially in the case of adding ovarian function suppression (OFS) to antihormone therapy. The authors investigated the impact of MDR on prognosis stratified by treatment based on the updated results of the ASTRRA trial. MATERIALS AND METHODS: The ASTRRA trial, a randomized phase III study, showed that adding OFS to tamoxifen (TAM) improved survival in premenopausal women with estrogen receptor-positive breast cancer after chemotherapy. The authors updated survival outcomes and assessed mammography before treatment and the annual follow-up mammography for up to 5 years after treatment initiation. Mammographic density (MD) was classified into four categories based on the Breast Imaging-Reporting and Data System. MDR-positivity was defined as a downgrade in MD grade on follow-up mammography up to 2 years after randomization, with pretreatment MD grade as a reference. RESULTS: The authors evaluated MDR in 944 of the 1282 patients from the trial, and 813 (86.2%) had grade III or IV MD. There was no difference in the MDR-positivity rate between the two treatment groups [TAM-only group (106/476 (22.3%)) vs. TAM+OFS group (89/468 (19.0%)); P =0.217). MDR-positivity was significantly associated with better disease-free survival (DFS) in the TAM+OFS group (estimated 8-year DFS: 93.1% in MDR-positive vs. 82.0% in MDR-negative patients; HR: 0.37; 95% CI: 0.16-0.85; P =0.019), but not in the TAM-only group ( Pinteraction =0.039). MDR-positive patients who received TAM+OFS had a favorable DFS compared to MDR-negative patients who received only TAM (HR: 0.30; 95% CI: 0.13-0.70; P =0.005). CONCLUSION: Although the proportion of MDR-positive patients was comparable between both treatment groups, MDR-positivity was independently associated with favorable outcomes only in the TAM+OFS group.

Exploring the Spatial Landscape of the Estrogen Receptor Proximal Proteome With Antibody-Based Proximity Labeling.

Estrogen receptor α (ERα) drives the transcription of genes involved in breast cancer (BC) progression, relying on coregulatory protein recruitment for its transcriptional and biological activities. Mutation of ERα as well as aberrant recruitment of its regulatory proteins contribute to tumor adaptation and drug resistance. Therefore, understanding the dynamic changes in ERα protein interaction networks is crucial for elucidating drug resistance mechanisms in BC. Despite progress in studying ERα-associated proteins, capturing subcellular transient interactions remains challenging and, as a result, significant number of important interactions remain undiscovered. In this study, we employed biotinylation by antibody recognition (BAR), an innovative antibody-based proximity labeling (PL) approach, coupled with mass spectrometry to investigate the ERα proximal proteome and its changes associated with resistance to aromatase inhibition, a key therapy used in the treatment of ERα-positive BC. We show that BAR successfully detected most of the known ERα interactors and mainly identified nuclear proteins, using either an epitope tag or endogenous antibody to target ERα. We further describe the ERα proximal proteome rewiring associated with resistance applying BAR to a panel of isogenic cell lines modeling tumor adaptation in the clinic. Interestingly, we find that ERα associates with some of the canonical cofactors in resistant cells and several proximal proteome changes are due to increased expression of ERα. Resistant models also show decreased levels of estrogen-regulated genes. Sensitive and resistant cells harboring a mutation in the ERα (Y537C) revealed a similar proximal proteome. We provide an ERα proximal protein network covering several novel ERα-proximal partners. These include proteins involved in highly dynamic processes such as sumoylation and ubiquitination difficult to detect with traditional protein interaction approaches. Overall, we present BAR as an effective approach to investigate the ERα proximal proteome in a spatial context and demonstrate its application in different experimental conditions.

Role of G-protein-coupled estrogen receptor in the pathogenesis of chronic asthma.

BACKGROUND AND AIM: G protein-coupled estrogen receptor (GPER) is an estrogen receptor located on the plasma membrane. We previously reported that the administration of G-1, a GPER-specific agonist, suppressed development of acute ovalbumin (OVA)-induced asthma in a mouse model. Herein, we evaluate the involvement of GPER in a mouse model of chronic OVA asthma. METHODS: G-1 or saline was administered subcutaneously to BALB/c mice with chronic OVA asthma, and pathological and immunological evaluation was performed. In addition, Foxp3-expressing CD4-positive T-cells in the spleen and ILC2 in the lungs were measured using flow cytometry. RESULTS: We observed a significant decrease in the number of inflammatory cells in the bronchoalveolar lavage fluid (BALF) in the G-1 treated group. In the airways, inflammatory cell accumulation, Th2 cytokines (IL-4, IL-5, IL-13, and eotaxin) and epithelial cytokine TSLP were suppressed, while in the BALF, anti-inflammatory cytokines (IL-10 and TGF-ß) were increased. Furthermore, in splenic mononuclear cells, Foxp3-expressing CD4-positive T-cells were increased in the G-1 group, whereas treatment with G-1 did not change the percentage of ILC2 in the lungs. CONCLUSION: G-1 administration suppressed allergic airway inflammation in mice with chronic OVA asthma. GPER may be a potential therapeutic target for chronic allergic asthma.

The infinite potential of a single substance: The history of tamoxifen as an example of drug repositioning / Nieskonczony potencjal jednej substancji: Historia tamoksyfenu jako przyklad repozycjonowania leków.

Known for a long time, well-tested substances are still finding new applications in science, medicine and industry. This is a popular and cost-effective strategy because, when searching for new applications, effective methods of their large-scale production and pharmacological activity, and the results of pharmacokinetic and toxicological studies are usually already known. Tamoxifen is known mainly as a drug used in the treatment of estrogen receptor-dependent breast cancer. Despite the discovery of this effective and profitable property many years ago and the constant expansion of related applications and patents, completely new ways of using tamoxifen and its derivatives in various fields continue to appear, and the number of patents for novel applications unrelated to breast cancer remains high. The aim of this article is to illustrate drug repositioning on the example of tamoxifen and to bring the ever-developing story of discoveries related to it to a wider audience.

Involvement of estrogen receptor activation in kaempferol-3-O-glucoside's protection against aging-related cognition impairment and microglial inflammation.

Estrogens have been demonstrated to inhibit age-related cognitive decline via binding to estrogen receptors (ERs). As a natural flavonoid component of Cuscuta Chinensis Lam., Kaempferol-3-O-glucoside (K-3-G) not only possesses anti-neuroinflammatory potential but also functions as an agonist for ERα and ERß. This study aimed to determine whether K-3-G improved cognition during the aging process, with an emphasis on its effect on microglial inflammation. In vivo, K-3-G (5 or 10 mg/kg/day) was orally given to the senescence-accelerated mouse prone 8 (SAMP8) mice from six to eight-month old. In addition to mitigating the memory and learning deficits of SAMP8 mice, K-3-G upregulated the expression of ERα and ERß in their hippocampal CA1 region, with the higher dose being more effective. Less Iba-1+ microglial cells presented in SAMP8 mice treated with K-3-G. The formation of NLR Family Pyrin Domain Containing 3 (NLRP3) complex, production of pro-inflammatory cytokines and oxidative stress-related markers, as well as expression of pro-apoptotic proteins were reduced by K-3-G. In vitro, BV2 microglial cells exposed to oligomeric amyloid beta (Aß)1-42 were treated with 100 µM K-3-G. K-3-G showed similar anti-inflammatory effects on BV2 cells as in vivo. K-3-G-induced alterations were partly diminished by fulvestrant, an ER antagonist. Moreover, dual-luciferase reporter system demonstrated that K-3-G induced ER expression by activating the transcription of estrogen-response elements (EREs). Collectively, these findings demonstrate that K-3-G may be a novel therapeutic agent for senescence-related cognitive impairment by inhibiting microglial inflammation through its action on ERs.

Complete pathological response in patients with HER2 positive breast cancer treated with neoadjuvant therapy in Colombia / Respuesta patológica completa de pacientes con cáncer de mama HER2 positivo tratadas con quimioterapia neoadyuvante en Colombia.

Introduction: Breast cancer is the most common type of cancer and the leading cause of death by cancer in women in Colombia. Approximately 15 to 20% of breast cancers overexpress HER2. Objective: To analyze the relationship between multiple clinical and histological variables and pathological complete response in patients with HER2-positive breast cancer undergoing neoadjuvant therapy in a specialized cancer center in Colombia. Materials and methods: We performed a retrospective analysis of non-metastatic HER2-positive breast cancer patients who received neoadjuvant therapy between 2007 and 2020 at the Instituto de Cancerología Las Americas Auna (Medellín, Colombia). Assessed parameters were tumor grade, proliferation index, estrogen receptor, progesterone receptor, HER2 status, type of neoadjuvant therapy, pathologic complete response rates, and overall survival. Results: Variables associated with low pathologic complete response rates were tumor grades 1-2 (OR = 0.55; 95% CI = 0.37-0.81; p = 0.03), estrogen receptor positivity (OR =0.65; 95%; CI = 0.43-0.97; p=0.04), and progesterone receptor positivity (OR = 0.44; 95% CI = 0.29-0.65; p = 0.0001). HER2 strong positivity (score 3+) was associated with high pathological complete response rates (OR = 3.3; 95% CI = 1.3-8.35; p=0.013). Five-year overall survival was 91.5% (95% CI = 82.6-95.9) in patients with pathological complete response and 73.6% (95% CI = 66.4-79.6) in patients who did not achieve pathological complete response (p = 0.001). Additionally, the pathological complete response rate was three times higher in patients receiving combined neoadjuvant chemotherapy with anti-HER2 therapy than in those with chemotherapy alone (48% versus 16%). Conclusions: In patients with HER2-positive breast cancer, tumor grade 3, estrogen receptor negativity, progesterone receptor negativity, strong HER2 positivity (score 3+), and the use of the neoadjuvant trastuzumab are associated with higher pathological complete response rates.

Research progress on tamoxifen and its analogs associated with nuclear receptors.

Tamoxifen, a triphenylethylene-based selective estrogen-receptor modulator, is a landmark drug for the treatment of breast cancer and is also used for treating liver cancer and osteoporosis. Structural studies of tamoxifen have led to the synthesis of more than 20 novel tamoxifen analogs as receptor modulators, including 16 ERα modulators 2-17, an ERRß inverse agonist 19 and six ERRγ inverse agonists 20-25. This paper summarizes the research progress and structure-activity relationships of tamoxifen analogs modulating these three nuclear receptors reported in the literature, and introduces the relationship between these three nuclear receptor-mediated diseases and tamoxifen analogs to guide the research of novel tamoxifen analogs.

Safety of Vaginal Estrogen Therapy for Genitourinary Syndrome of Menopause in Women With a History of Breast Cancer.

OBJECTIVE: To assess the risk of recurrence of breast cancer associated with vaginal estrogen therapy in women diagnosed with genitourinary syndrome of menopause with a history of breast cancer using a large U.S. claims database. METHODS: A U.S. health research network (TriNetX Diamond Network) was queried from January 2009 to June 2022. Our cohort consisted of women diagnosed with breast cancer within 5 years before the initial genitourinary syndrome of menopause diagnosis. Patients with active disease , defined as those undergoing mastectomy, radiation treatment, or chemotherapy within 3 months before diagnosis of genitourinary syndrome of menopause, were excluded. Recurrence was defined as mastectomy, radiation, chemotherapy, or secondary malignancy within 3 months to 5 years after the initiation of vaginal estrogen therapy for genitourinary syndrome of menopause. The study cohort included those with three or more vaginal estrogen prescriptions. The control cohort included women with breast cancer without any vaginal estrogen prescriptions after genitourinary syndrome of menopause diagnosis. Propensity matching was performed. A subanalysis by positive estrogen receptor status, when available, was performed. RESULTS: We identified 42,113 women with a diagnosis of genitourinary syndrome of menopause after breast cancer diagnosis with any estrogen receptor status, 5.0% of whom received vaginal estrogen. Of the initial cohort, 10,584 patients had a history of positive estrogen receptor breast cancer, and 3.9% of this group received vaginal estrogen. Risk of breast cancer recurrence was comparable between those who received vaginal estrogen and those who did not in both the any estrogen receptor (risk ratio 1.03, 95% CI 0.91-1.18) and positive estrogen receptor (risk ratio 0.94, 95% CI 0.77-1.15) status analyses. CONCLUSION: In a large, claims-based analysis, we did not find an increased risk of breast cancer recurrence within 5 years in women with a personal history of breast cancer who were using vaginal estrogen for genitourinary syndrome of menopause.

The effect of prolonged neoadjuvant endocrine therapy on the efficacy of treatment with breast cancer.

BACKGROUND: At present, there is no consensus on the required duration of neoadjuvant endocrine therapy (NET), yet there is no consistent conclusion on the factors influencing the efficacy of treatment with breast cancer after prolonged treatment. OBJECTIVE: To explore the effect of prolonged NET on the efficacy of patients with breast cancer and analyze the factors influencing the efficacy of treatment with breast cancer after the treatment duration is prolonged. METHODS: The case histories of 51 patients who were diagnosed with breast cancer and received NET in our hospital from September 2017 to December 2021 were retrospectively analyzed. All patients received NET for over 12 months. The clinical efficacy and tumor size changes after treatment for six months and 12 months were compared, and the factors influencing the efficacy of treatment with breast cancer after patients' treatment duration was prolonged were analyzed. RESULTS: (1) Among the 51 patients, the objective remission rate (ORR) of NET, at T = 6 months was 21.6%, and the average tumor size was 15.52 ± 7.30 mm. The ORR of the NET at T = 12 months was 52.9%, and the average tumor size was 13.79 ± 7.43 mm. (2) After the treatment duration was prolonged, the clinical ORRs of patients with estrogen receptor (ER) (+) and progesterone receptor (PR) (+) were significantly higher than that of patients with ER (+) and PR (-) and patients with ER (-) and PR (+), which was (P < 0.05). (3) There was no significant difference between the patients' axillary lymph node status and the Ki67 expression before treatment and the clinical ORR after prolonged treatment, which was (P> 0.05). CONCLUSIONS: (1) Prolonging the NET duration for patients with breast cancer can improve their clinical ORR and further reduce the tumor size, but patients' conditions should be closely monitored during the treatment process to prevent the progression of disease due to drug resistance. (2) The expression state of ER or PR may be used as a factor influencing the efficacy of treatment with breast cancer after prolonged treatment. (3) There was no significant effect on the patients' axillary lymph node status and the Ki67 expression before treatment on the clinical efficacy after prolonged treatment.

Targeting autophagy with tamoxifen in breast cancer: From molecular mechanisms to targeted therapy.

BACKGROUND: Tamoxifen (TAM) is often recommended as a first-line treatment for estrogen receptor-positive breast cancer (BC). However, TAM resistance continues to be a medical challenge for BC with hormone receptor positivity. The function of macro-autophagy and autophagy has recently been identified to be altered in BC, which suggests a potential mechanism for TAM resistance. Autophagy is a cellular stress-induced response to preserve cellular homeostasis. Also, therapy-induced autophagy, which is typically cytoprotective and activated in tumor cells, could sometimes be non-protective, cytostatic, or cytotoxic depending on how it is regulated. OBJECTIVE: This review explored the literature on the connections between hormonal therapies and autophagy. We investigated how autophagy could develop drug resistance in BC cells. METHODS: Scopus, Science Direct, PubMed, and Google Scholar were used to search articles for this study. RESULTS: The results demonstrated that protein kinases such as pAMPK, BAX, and p-p70S6K could be a sign of autophagy in developing TAM resistance. According to the study's findings, autophagy plays an important role in BC patients' TAM resistance. CONCLUSION: Therefore, by overcoming endocrine resistance in estrogen receptor-positive breast tumors, autophagy inhibition may improve the therapeutic efficacy of TAM.

Estrogen-Induced LncRNA, LINC02568, Promotes Estrogen Receptor-Positive Breast Cancer Development and Drug Resistance Through Both In Trans and In Cis Mechanisms.

Endocrine therapy is the frontline treatment for estrogen receptor (ER) positive breast cancer patients. However, the primary and acquired resistance to endocrine therapy drugs remain as a major challenge in the clinic. Here, this work identifies an estrogen-induced lncRNA, LINC02568, which is highly expressed in ER-positive breast cancer and functional important in cell growth in vitro and tumorigenesis in vivo as well as endocrine therapy drug resistance. Mechanically, this work demonstrates that LINC02568 regulates estrogen/ERα-induced gene transcriptional activation in trans by stabilizing ESR1 mRNA through sponging miR-1233-5p in the cytoplasm. Meanwhile, LINC02568 contributes to tumor-specific pH homeostasis by regulating carbonic anhydrase CA12 in cis in the nucleus. The dual functions of LINC02568 together contribute to breast cancer cell growth and tumorigenesis as well as endocrine therapy drug resistance. Antisense oligonucleotides (ASO) targeting LINC02568 significantly inhibits ER-positive breast cancer cell growth in vitro and tumorigenesis in vivo. Furthermore, combination treatment with ASO targeting LINC02568 and endocrine therapy drugs or CA12 inhibitor U-104 exhibits synergistic effects on tumor growth. Taken together, the findings reveal the dual mechanisms of LINC02568 in regulating ERα signaling and pH homeostasis in ER-positive breast cancer, and indicated that targeting LINC02568 might represent a potential therapeutic avenue in the clinic.

Longitudinal multi-omics study of palbociclib resistance in HR-positive/HER2-negative metastatic breast cancer.

BACKGROUND: Cyclin-dependent kinase 4/6 inhibitor (CDK4/6) therapy plus endocrine therapy (ET) is an effective treatment for patients with hormone receptor-positive/human epidermal receptor 2-negative metastatic breast cancer (HR+/HER2- MBC); however, resistance is common and poorly understood. A comprehensive genomic and transcriptomic analysis of pretreatment and post-treatment tumors from patients receiving palbociclib plus ET was performed to delineate molecular mechanisms of drug resistance. METHODS: Tissue was collected from 89 patients with HR+/HER2- MBC, including those with recurrent and/or metastatic disease, receiving palbociclib plus an aromatase inhibitor or fulvestrant at Samsung Medical Center and Seoul National University Hospital from 2017 to 2020. Tumor biopsy and blood samples obtained at pretreatment, on-treatment (6 weeks and/or 12 weeks), and post-progression underwent RNA sequencing and whole-exome sequencing. Cox regression analysis was performed to identify the clinical and genomic variables associated with progression-free survival. RESULTS: Novel markers associated with poor prognosis, including genomic scar features caused by homologous repair deficiency (HRD), estrogen response signatures, and four prognostic clusters with distinct molecular features were identified. Tumors with TP53 mutations co-occurring with a unique HRD-high cluster responded poorly to palbociclib plus ET. Comparisons of paired pre- and post-treatment samples revealed that tumors became enriched in APOBEC mutation signatures, and many switched to aggressive molecular subtypes with estrogen-independent characteristics. We identified frequent genomic alterations upon disease progression in RB1, ESR1, PTEN, and KMT2C. CONCLUSIONS: We identified novel molecular features associated with poor prognosis and molecular mechanisms that could be targeted to overcome resistance to CKD4/6 plus ET. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03401359. The trial was posted on 18 January 2018 and registered prospectively.

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

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

Identifying Patterns and Barriers in OncotypeDX Recurrence Score Testing in Older Patients With Early-Stage, Estrogen Receptor-Positive Breast Cancer: Implications for Guidance and Reimbursement.

PURPOSE: To evaluate the clinical patterns of utilization of OncotypeDX Recurrence Score (RS) in early-stage, hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer (BC) at an academic center with previously established internal reflex testing guidelines. METHODS: RS testing in accordance with preexisting reflex criteria and predictors of utilization outside of reflex criteria were retrospectively analyzed for the years 2019-2021 in a quality improvement evaluation. Patients were grouped according to OncotypeDX testing within (cohort A) or outside (cohort B) of predefined criteria which included a cap at age older than 65 years. RESULTS: Of 1,687 patients whose tumors had RS testing, 1,087 were in cohort A and 600 in cohort B. In cohort B, nearly half of patients were older than 65 years (n = 279; IQR, 67-72 years). For patients older than 65 years, those with RS testing were younger (median age: 69 v 73 years), with higher grade cancers (G2-3: 84.9% v 54.7%) and were more likely to be treated with chemotherapy (15.4% v 4.1%). Issues for implementation of RS testing in older patients were identified, including potential structural barriers related to the current policy on the reimbursements of genomic tests. CONCLUSION: Internal guidelines may facilitate standardized utilization of the RS in early-BC. Our data suggest that clinicians preferred broader utilization of RS across the age spectrum, with therapeutically important consequences. Modifying the current policy for reimbursement of RS testing and in internal reflexive testing criteria for those older than 65 years is warranted.