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Context and objective. Despite the high frequency of Benign Breast Tumors (BBT) in sub-Saharan Africa, very few studies have been conducted on these tumors. The objective of the present study was to evaluate the diagnostic value of clinical and ultrasound breast examinations for BBT in poorly equipped settings. Methods. This was a retrospective analysis of BBT cases followed at the Kinshasa University Hospital, between January 2016 and December 2021. The diagnostic value of clinical and ultrasound explorations of BBT (sensitivity, specificity, negative predictive value NPV, PPV, Kappa coefficient) was calculated taking as reference the anatomopathological finding of biopsy parts. Results. A total of 81 cases of BBT were collected. Fibroadenoma 58 (71.6%), Fibrocystic disease (MFK) 15 (18.5%), Tubular adenoma 6 (7.4%), Phyllodes tumor (PT) 1 (1.2%) and cyst 1 (1.2%) were diagnosed on the basis of pathological analyses after lumpectomy. On clinical examination, the ability to diagnose BBT other than Fibroadenoma was zero. The specificity, NPV and kappa coefficient were 60.0%, 39.1% and 32.2%, respectively for the diagnosis of Fibroadenoma. Breast ultrasound was performed in 98.6% while mammography in only 11.1% of cases. The majority of tumors were classified as Breast Imaging reporting and Data system (BIRADS) 2 (70.0%). Specificity, NPV and kappa were 80.6%, 40.9% and 39.0% for Fibroadenoma, respectively, and 84.4%, 66.7% and 1.9% for MFK. PT was classified as BIRADS3. Conclusion. Breast ultrasonograpy performs well in the BIRADS classification of BBT; clinicians practicing in low-equipped settings can therefore unequivocally follow the recommendations on the management of tumors classified as BIRADS2 and BIRADS3 on ultrasonography, although the performance with respect to the differential diagnosis of these tumors is debatable. Contexte et objectif. Malgré leur fréquence élevée, très peu d’études ont été menées sur les tumeurs bénignes du sein (TBS) en Afrique subsaharienne. L’objectif de la présente étude a été d’évaluer la valeur diagnostique des explorations clinique et échographique mammaire des TBS en milieu peu équipé. Méthodes. Il s’agissait d’une étude documentaire, sur les TBS suivies aux Cliniques Universitaires de Kinshasa, entre janvier 2016 et décembre 2021. La valeur diagnostique des explorations clinique et échographique mammaire des TBS (sensibilité, spécificité, valeur prédictive négative VPN, VPP, coefficient Kappa) a été calculée en prenant pour référence la découverte anatomopathologique des pièces biopsiques. Résultats. Au total, 81 dossiers de TBS ont été colligés. Le Fibroadénome 58 (71,6 %), la Maladie fibrokystique (MFK) 15 (18,5 %), l’Adénome tubuleux 6(7,4 %), la Tumeur Phyllode (TP) 1(1,2 %) et le kyste 1(1,2 %) étaient les tumeurs diagnostiquées à l’anatomopathologie, après tumorectomies. A l’examen clinique, la capacité diagnostique des TBS autres que le Fibroadénome était nulle. La spécificité, la VPN et le coefficient kappa étaient respectivement, de 60,0 %, 39,1 % et 32,2 % pour le diagnostic du Fibroadénome. L’échographie mammaire était faite dans 98,6 % tandis que la mammographie seulement dans 11,1 % des cas. La majorité des tumeurs étaient classées Breast Imaging reporting and Data system (BIRADS) 2 (70,0 %). La spécificité, la VPN et le coefficient kappa étaient respectivement, de 80,6 %, 40,9 % et 39,0 % pour le Fibroadénome, et de 84,4 %, 66,7 % et 1,9 % pour la MFK. La TP était classée BIRADS3. Conclusion. L’échographie mammaire très réalisée, est très performante dans la classification BIRADS des TBS; les cliniciens exerçant en milieu peu équipé peuvent donc sans équivoque suivre les recommandations sur la prise en charge des tumeurs classées BIRADS2 et BIRADS3 à l’échographie, bien que sa performance en ce qui concerne le diagnostic différentiel de ces tumeurs soit moindre.

Tumorske bolesti dojke bile one benigne ili maligne velik su zdravstveni problem. Benigni tumori dojke najčešće se javljaju u žena mlađe životne dobi, mogu se pojaviti već u adolescentnoj fazi života. Od malignih tumora dojke obolijevaju većinom žene iznad 50-te godine života, iako se i maligni tumori javljaju u sve mlađoj dobi. Potrebno je educirati žene o važnosti izvođenja samopregleda dojki kako bi na vrijeme primijetile pojavnost prvih simptoma bolesti. Rad je sastavljen od nekoliko poglavlja kroz koja se opisuje anatomija i fiziologija dojke, patološke promjene tumora dojke te kritični čimbenici za nastanak bolesti. Kroz rad je obuhvaćena i klasifikacija tumora dojke, odnosno stadiji bolesti. Također proces dijagnosticiranja i liječenja bolesti zajedno sa sestrinskom skrbi pacijenata prije i nakon operacijskog zahvata na dojci. U radu je prikazano istraživanje kojim su prikazani podaci o učestalosti tumora dojke u Općoj bolnici Pula. Osim broja oboljelih osoba u zadnjih 10 godina prikazani su i operacijski zahvati kojima su liječene osobe oboljele od tumorskih bolesti dojke. Breast tumor diseases, either benign or malignant, represent big health issue. Benign breast tumors most often occur in women of younger age, they can appear even in their adolescent years. Malignant breast tumors are most often in women over 50 years old, even though malignant breast tumors are more and more common at a younger age. It is necessary to educate women about the importance of a breast self exam in order to notice first symptoms in time. This paper is composed of several chapters describing the anatomy and physiology of the breast, pathological changes of breast tumors and critical factors for the development of the disease. The work covers the classification of breast tumors, that is stages of the disease, and the process of diagnosing and treating diseases together with nursing care of the patient before and after breast surgery. The paper presents a study that presented data on the frequency of breast tumors in General hospital Pula. In addition to the number of patients in the last 10 years, the surgical procedures that were used to treat people suffering from breast tumor diseases are also presented.

Automatic classification of benign and malignant breast ultrasound images is an important and challenging task to improve the efficiency and accuracy of clinical diagnosis of breast tumors and reduce the rate of missed and misdiagnosis. The task often requires a large amount of data to train. However, it is difficult to obtain medical images, which contradicts the large amount of data needed to obtain good diagnostic models for training. In this paper, a novel classification model for the classification of breast tumors is proposed to improve the performance of diagnosis models trained by small datasets. The method integrates three features from medical features extracted from segmented images, features selected from the pre-trained ResNet101 output by principal component analysis (PCA), and texture features. Among the medical features that are used to train the naive Bayes (NB) classifier, and the PCA-selected features are used to train the support vector machine (SVM) classifier. Subsequently, the final results of boosting are obtained by weighting the classifiers. A five-fold cross-validation experiment yields an average accuracy of 89.17%, an average precision of 90.00%, and an average AUC value of 0.95. According to the experimental results, the proposed method has better classification accuracy compared to the accuracy obtained by other models trained on only small datasets. This approach can serve as a reliable second opinion for radiologists, and it can also provide useful advice for junior radiologists who do not have sufficient clinical experience.

INTRODUCTION: Breast cancer (BC) is a highly prevalent and heterogeneous disease, entailing different so-called intrinsic subtypes (IS) according to gene expression, namely Luminal A, Luminal B, HER2-Enriched (HER2E) and Basal-like, as well as a normal breast-like group. The HER2E is still a poorly understood entity, which needs further biologic characterization to improve therapeutic management. MATERIAL AND METHODS: Patients (pts) treated at Hospital Clinic (Barcelona, Spain) over 18 years with a diagnosis of metastatic BC, with available matched primary and metastatic tumor samples for gene expression analyses were retrospectively recruited. Using the nCounter® Breast Cancer 360 panel, we studied the expression of 776 genes pertaining to different tumor and immune pathway-related signatures, with a focus on HER2E vs. non-HER2E tumors. Significant changes were considered at a false discovery rate (FDR) < 5%. Main clinicopathological features were also compared. IS changes from primary to metastatic disease were assessed. RESULTS: Ninety-one pts with paired tumor samples were included. Briefly, primary tumors were 67.0% hormone receptor-positive (HR+)/HER2-negative (HER2-), 14.8% were HER2-positive (HER2+) and 18.2% were triple-negative (TNBC). IS distribution in primary tumors was the following: 25 Luminal A (28%), 22 Luminal B (24%), 24 HER2E (26%), 12 Basal-like (13%), and 8 Normal-like (9%). In contrast, IS distribution in metastatic tumors was the following: 13 Luminal A (14%), 22 Luminal B (24%), 34 HER2-E (37%), 16 Basal-like (18%), and 6 Normal-like (7%). The HER2E disease proved to be a relatively stable subtype, with 16 (66.7%) tumors not changing IS in the transition to metastatic disease (p=0.078). Particularly, within HR+/HER2-, HER2+ and TNBC, 8/12 (66.7%), 8/10 (80.0%) and 1/2 (50.0%) tumors remained HER2E. Conversely, an overall significant switch from Luminal to non-Luminal tumors at the metastatic progression was observed (p=0.031), with 14/19 (73.7%) new non-Luminal BC being HER2E. When considering all primary and metastatic tumors, HER2E were observed to be less frequently estrogen receptor (ER) positive than non-HER2E tumors (55.8% vs. 78.7%; p=0.002), with lower mean progesterone receptor (PR) levels (15.3% vs. 25.8%; p=0.027). Compared to the other subtypes (as a group), the PAM50 risk of recurrence score (ROR-P) was higher for HER2E tumors (59.1 vs. 41.7; p < 0.001), which were also more frequently HER2+ (36.5% vs. 5.8%) and less likely HR+/HER2- (50.0% vs. 73.6%) and TNBC (13.5% vs. 20.7%), compared to non-HER2E (p < 0.001). No significant differences in grade, TILs, Ki67 and histotype were observed. Overall, 140/776 genes were significantly downregulated in HER2E vs. non-HER2E tumors, including genes related to cell adhesion, migration, DNA damage repair, apoptosis, estrogen signalling pathway, senescence. Conversely, 178/776 genes were significantly upregulated, including the tyrosine-kinase receptor FGFR4, genes involved in nuclear activity, DNA transcription regulation, MAP-kinase signaling pathways, proliferation, cytokine response, epithelial-to-mesenchymal transition (EMT), cell cycle progression, and immune-related genes such as CD274 (PD-L1 gene). DISCUSSION: A switch towards more aggressive IS from primary to advanced disease was observed, with an increase in HER2E prevalence. HER2E tumors, which tend to maintain their IS at the metastatic disease, showed upregulation of genes related to proliferation, survival and EMT, coherently with their well-known worse prognosis. FGFR4 and CD274 upregulation, along with downregulation of genes involved in DNA damage repair suggest these tumors might benefit from targeted therapeutic approaches. Genomic higher risk was not convoyed by consistent clinicopathological features, except for lower PR levels and HER2 overexpression at IHC. Further characterization according to primary/metastatic and HR status is ongoing. Intrinsic subtype distribution across primary and metastatic breast tumors Citation Format: Francisco Javier Muñoz-Carrillo, Laia Paré, Benedetta Conte, Adela Rodríguez, Patricia Galván, Esther Sanfeliu, Blanca González-Farré, Claudette Falato, Isabel Garcia-Fructuoso, Barbara Adamo, Nuria Chic, Olga Martínez-Sáez, Tomás Pascual, Reinaldo Moreno, Montserrat Muñoz, Fara Brasó-Maristany, Aleix Prat, Francesco Schettini, Maria Vidal. Clinico-Pathological and Molecular Characterization of HER2-Enriched Breast Tumors Independently of HER2 Status [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-23-16.

A Novel Single Cell Model of Tamoxifen Response in Primary Human Breast Tumors Austin Whitman, Hyunsoo Kim, Kamila Wisniewska, Rasha Kakati, Susana Garcia Recio, Hector Franco, Charles Perou, Philip Spanheimer Background: Resistance to endocrine therapy is a primary cause of treatment failure and death in patients with estrogen receptor (ER)-positive breast cancer. Intratumor heterogeneity is associated with resistance to therapy across tumors, and specifically in ER+/HER2- breast cancer, heterogeneity in ER and PR expression is associated with a worse response to endocrine therapy. We hypothesize that subpopulations within and across ER+/HER2- human breast tumors have distinct responses to tamoxifen and that discerning heterogeneity in response will improve understanding of inherent and emerging resistance to endocrine therapy. Methods: We developed an operating room-to-laboratory pipeline immediately after surgical resection for studies using alive tissue. Tissue samples were obtained and single cell suspensions created using physical and enzymatic dissociation. Cells were treated with tamoxifen (10 M) or control media for 12 hours in suspension and single cell RNA libraries generated using the 10X Genomics droplet-based kit and sequenced using the Illumina NextSeq2000. Results: We obtained normal breast tissue from 2 women undergoing reduction mammoplasty and tumor tissue from 10 women with ER+/HER2- invasive breast carcinoma. In tamoxifen treated and control matched pairs, a total of 22,195 cells from normal breast and 94,558 cells from tumor samples were sequenced. Computational analysis using consensus clustering was performed and cell types assigned using canonical correlation. Both tumor and normal samples identified clustering by cell type and not by patient revealing significant variability in cell type abundance between samples. In the normal breast samples, we performed differentially expressed genes (DEG) analysis comparing tamoxifen treatment to control for each cell type (Immune cells, fibroblasts, basal epithelial cells, luminal progenitor cells, and mature luminal cells) and enrichment analysis of up- and down-regulated genes performed. Strong depletion of estrogen induced genes was observed in tamoxifen-treated normal luminal progenitor and mature luminal cells, but not in basal epithelial cells or fibroblasts, demonstrating distinct, subpopulation-specific response to tamoxifen. In the 10 tumor matched pairs, 4 had a high epithelial proportion and tumor cells identified using inferred copy number variation. Tumor cells in 3 of these 4 samples showed significant down regulation of estrogen response genes with tamoxifen treatment. Using scBCSubtype to assign PAM50 subtype to individual tumor cells, the 3 responsive tumors were comprised primarily of LumA cells while the unresponsive tumor was predominantly LumB. Finally, we developed a novel score to quantify responsiveness at the single cell level based on downregulation of estrogen response genes with tamoxifen treatment relative to matched cluster-specific untreated expression. This analysis demonstrated heterogeneity in response to tamoxifen in tumor cells and identified distinct subpopulations of responsive and unresponsive tumor cells to tamoxifen treatment. Conclusion: We developed a novel ex vivo model to determine heterogeneity in therapeutic response to tamoxifen in normal human breast tissue and primary human breast tumors. We demonstrate differences in tamoxifen response by cell type and identify distinctly responsive and resistant subpopulations within human tumors. This provides a foundation to define features of responsive and resistant populations on the individual cell and specimen basis, and should allow us to develop precise, single cell-based predictors of response to endocrine therapy, and to identify genes and pathways driving resistance to therapy. Citation Format: Hyunsoo Kim, Austin Whitman, Kamila Wisniewska, Susana Garcia-Recio, Rasha Kakati, Hector L. Franco, Charles M. Perou, Philip Spanheimer. PD4-08 A Novel Single Cell Model of Tamoxifen Response in Primary Human Breast Tumors [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD4-08.

Background PD-1 inhibitors have shown significant efficacy in triple negative breast cancer (BC), however, durable responses are less common in estrogen receptor-positive (ER+) BC. Better markers are therefore needed that will identify likely responders to PD-1 inhibitors among patients with luminal BC. While most efforts have focused on the immune checkpoint protein PD-L1, the alternative PD-1 ligand, PD-L2, has been largely overlooked. We aimed to determine if PD-L2 is associated with unfavorable prognosis in ER+ BC. Methods PD-L2 protein levels in cancer cells and stromal cells were measured retrospectively by quantitative immunofluorescence histocytometry in tissue microarrays of therapy-naïve, localized or locoregional ER+ BC and correlated with progression-free survival (PFS). Evaluable tumor PD-L2 data were derived from a main study cohort A diagnosed between 1988-2005 (n=684) with extensive clinical and outcome data and from an independent validation cohort B diagnosed between 1992-2012 (n=273). Patients received standard-of-care adjuvant therapy without immune checkpoint inhibitors after tumor resection. Results Univariate analysis of the main cohort A revealed that high PD-L2 expression in cancer cells was associated with shorter PFS (HR=1.8; 95%CI:1.3-2.6; p=0.001), an observation that was validated in an independent cohort B (HR=2.3, 95%CI:1.1-4.8; p=0.026). Approximately one third of ER+ BC cases were classified as high PD-L2. After multivariable adjustment for common clinicopathological variables, high cancer cell levels of PD-L2 remained independently predictive of early recurrence (HR=2.0; 95%CI:1.4-2.9; p< 0.001). Sub-analysis of ER+ BC cases treated with adjuvant chemotherapy (n=197) suggested that high PD-L2 levels in cancer cells was associated with particularly increased risk of progression (multivariable HR=3.4; 95%CI:1.9-6.2; p< 0.001). The observed frequent expression of PD-L2 protein in BC provided scientific rationale for the design of our ongoing phase II clinical trial (NCT04243616) of neoadjuvant combined PD-1 inhibitor (cemiplimab; Regeneron Pharmaceuticals Inc) and chemotherapy in patients diagnosed with PD-L1+ and/or PD-L2+ BC. The primary objective of this trial is to assess pathologic responses to neoadjuvant treatment with secondary objective of assessing the correlation between PD-L1/PD-L2 status and tumor responses. Pathologist review of PD-L1 and PD-L2 expression in an initial set of ER+ tumors (n=15) screened for trial eligibility revealed frequent discordance between cancer cell positivity for PD-L1 and PD-L2 protein (PD-L1: median=0%; range 0-2% vs. PD-L2: median=18%; range < 1-60%) as well as immune cell positivity (PD-L1: median=5%; range 0-50% vs. PD-L2: median=0; range 0-50%). Conclusions In treatment-naïve ER+ breast tumors, high cancer cell expression of PD-L2 protein was an independent predictor of poor clinical outcome, with evidence of further elevated risk of progression in patients who received adjuvant chemotherapy. Preliminary analyses of ER+ tumors from our ongoing clinical trial showed frequent discordance between baseline PD-L1 and PD-L2 protein expression in both cancer cells and immune cells. Collectively, our analyses indicate that PD-L2 has prognostic value for ER+ BC, and our progress justify further studies to determine whether PD-L2, alone or in combination with PD-L1, may serve as a predictive marker of response to PD-1 inhibitors. Citation Format: Lubna N. Chaudhary, Inna Chervoneva, Amy R. Peck, Yunguang Sun, Misung Yi, John F. Langenheim, Julie M. Jorns, Sailaja Kamaraju, Yee Chung Cheng, John Burfeind, Christopher R. Chitambar, Jeffrey A. Hooke, Albert J. Kovatich, Craig Shriver, Hai Hu, Juan P. Palazzo, Marluce Bibbo, Terry Hyslop, Richard Pestell, Edith P. Mitchell, Hallgeir Rui. High PD-L2 Protein Expression in Cancer Cells is an Independent Marker of Unfavorable Prognosis in Luminal Breast Tumors [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-11-13.

Background: Epithelial-mesenchymal transition (EMT) phenotype is a complex process and plays a central role in tumor progression, aggression, invasion, metastasis, and resistance to therapy. Role of androgen receptor (AR) and androgens in inducing EMT has been well established in experimental systems of prostate cancer. AR is widely expressed in all subtypes of breast cancer (BC) and is considered to have context dependent role based on the steroid hormone microenvironment. Previous studies have shown AR as the only sex steroid receptor detectable in BC metastases and in metastatic lesion. We investigated the role of androgens in driving the EMT phenotype and association of AR induced genes with EMT in BC tumors using public dataset. Methods: We treated AR positive breast cancer cell line MDA-MB-453 with the androgen, dihydrotestosterone (DHT) followed by AR antagonist bicalutamide (Bic) and examined the expression levels of AR induced genes by quantitative real time PCR (qPCR) and AR induced protein GCDFP-15 by western blot. AR driven genes (SEC14L2, C1orf116, FKBP5, UGT2B11, UGT2B28, KCNMA1, PIP and ABCC11) were identified by bioinformatic pipeline using a systematic bioinformatic approach from public microarray data sets derived from AR positive breast cancer cell lines (S Rajarajan et al, SABCS 2021). Mesenchymal phenotype of the cell lines under DHT/Bic was evaluated morphologically and expression levels of EMT markers (ZEB1, Slug, Vimentin) and E-cadherin was estimated by qPCR, western blot and immunofluorescence. Migratory potential of the cell line under treatment was evaluated by wound healing assay and proliferation was examined by the MTT assay. Association of AR induced genes and levels of enzymes involved in intracrinal testosterone metabolism (SRD5A1 & SRD5A3) with EMT in breast tumors was evaluated using transcript data from METABRIC database. EMT scores were derived from previous publications (Byers et al, 2013, Mak et al, 2016) and correlation was tested with AR induced genes. Results: The MDAMB-453 cell line was treated with 10nM DHT for 72hrs and this increased the expression of AR downstream protein GCDFP-15 by 31.47% (p=0.022) when compared to the control. Further, a significant increase in the expression levels of AR driven genes with a fold change >2 was observed in the DHT treated cells (p< 0.05). The expression of GCDP15 protein (p=0.028) and the AR downstream genes (p< 0.05) were significantly repressed upon treatment with bicalutamide. DHT treatment also showed a significant higher expression of EMT master regulator, SLUG (fold change>3, p=0.045) and a wound healing assay showed a 22% increase in migration (p=0.027). The expression of SLUG was significantly repressed (p=0.003) and the migratory ability of the DHT treated cells reduced upon treatment with bicalutamide (p=0.145). We also observed a significant loss of E-cadherin protein (by 23.65%; p=0.024) with DHT treatment and this was completely reversed upon treatment with bicalutamide (p=0.047). No significant change in proliferation was observed among the different treatment conditions. A significant positive correlation was observed between AR induced genes and the EMT scores (p< 0.05). Expression level of SRD5A3 was also positively correlated with EMT score (p=0.043) and AR induced genes (p< 0.05), except SEC14L2. Conclusion: Androgen receptor plays an important role in the biology of breast cancer and is considered a useful marker for prognosis. However, antiandrogen therapies haven’t seen the expected success in clinical trial settings. Our results support the controversial role played by AR in higher androgenic environment within breast cancer and warrant the consideration of the intratumoral levels of sex steroid hormones. Citation Format: Savitha Rajarajan, Snijesh VP, Madhumathy G Nair, Apoorva D, Chandrakala M, Vidya P Nimbalkar, Maalavika Pillai, Mohit Kumar Jolly, Jyothi S Prabhu. Androgen mediated signaling induces epithelial to mesenchymal transition phenotype in MDA-MB-453 breast cancer cells and human breast tumors [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-19-02.

Breast tumor is one of the leading causes of death in women worldwide. The term tumor is often used for all lumps found in the human body. The increase in the number of cases of breast tumors that occur each year is due to the absence of prevention or early detection. The research was carried out by utilizing the development of information technology to create a breast tumor detection system with digital image processing. The application system will process mammogram images to detect edges with the canny method and will be classified using the SVM method. The data used is 176 data obtained from the Kaggle dataset. The test results revealed that 64 patients were classified as having malignant breast tumors (M), and 113 did not have breast tumors (B), with a classification accuracy rate of 95%. From the results obtained, the application system is very good for the early identification of breast tumors.

Next-generation oral selective estrogen receptor degraders (ngSERDs) are aiming to become the backbone endocrine therapy (ET) for patients with estrogen receptor positive (ER+) breast cancer (BC) by achieving greater ER signaling blockade than current therapies and tackling key mechanisms of resistance. Camizestrant (AZD9833) is an ngSERD for the treatment of ER+ BC which has demonstrated selective ERα degradation, pure ER antagonism and significant anti-tumor activity in ESR1 wild-type (ESR1wt) and mutant (ESR1m) tumors, as well as encouraging clinical activity in early phase trials. ER+ BC is responsive to therapies targeting ER and CDK4/6 signaling in the adjuvant and metastatic settings. To explore camizestrant combination potential as a backbone ET, camizestrant was partnered with either palbociclib or abemaciclib in CDK4/6 inhibitor (CDK4/6i) naïve and resistant in vitro and in vivo models. Combination benefit was observed in vitro in 3 parental ER+ BC cell lines, moreover camizestrant plus abemaciclib showed activity in palbociclib-resistant cell lines including lines harboring CCNE1amp and RB1 loss. In vivo, combination of camizestrant and either CDK4/6i was well tolerated with the combinations promoting improved efficacy in ESR1wt and ESR1m PDX tumor models compared to monotherapy arms. ER+ BC has a high prevalence of alterations in the PI3K/AKT/PTEN pathway which provides opportunities for treatment with PI3K/AKT pathway inhibitors. Camizestrant delivered enhanced efficacy when combined with mTORC1 inhibitor everolimus and AKT inhibitor capivasertib in CTC-174, an ESR1m and PI3KCAm tumor model. Additionally, combination with capivasertib was more efficacious than single treatments, at clinically relevant dose and schedules, in both PI3Kwt and mutated pathway in PDX models. These data demonstrate the interplay between PI3K/AKT/PTEN pathway inhibition and camizestrant mechanism of action. Finally, we explored a potential triple combination of camizestrant, capivasertib and palbociclib in Palbociclib-resistant models representative of PI3KCA/AKT/PTEN wt and altered tumors. This strategy delivered robust efficacy across these models comparing to single treatments and double combinations. The triplet led to durable regressions at clinically achievable doses of all compounds, irrespective of genetic background and aligned to biomarker modulation of the three signaling axis. These preclinical data demonstrate the potential of camizestrant to become the backbone ET, with high combinability in vivo with inhibitors of CDK4/6, mTOR and AKT. These combinations demonstrate the opportunity to impact care of patients with early and metastatic ER+BC, delivering benefit to broad patient populations including those with ESR1wt or ESR1m tumors, independent of PI3K/AKT/PTEN pathway mutation status, and in patients with both CDK4/6i sensitive and resistant tumors. Citation Format: Larissa Carnevalli, Susana Ros, Jelena Urosevic, Natalie Cureton, Sophie Darcy, Mandy Lawson, Stuart Williamson, Pablo Morentin Gutierrez, Azadeh Bashi, Jennifer Moss, Christopher Morrow, Barry Simon, Teresa Klinowska. PD10-04 Combination of the next generation oral SERD camizestrant (AZD9833) with CDK4/6 and mTOR/AKT inhibitors delivers robust efficacy in a broad range of ER+ breast tumors. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD10-04.

Background: CDK4/6 inhibitors (CDK4/6i) are standard of care for the management of HR+/HER2- metastatic breast cancer (MBC). Genomic alterations that drive resistance to CDK4/6i are diverse, and while the molecular landscape is heterogeneous, several mechanisms of CDK4/6i resistance converge on the RAS/MAPK and PI3K/AKT/mTOR signaling pathways. NF1 downregulates RAS and dampens cellular proliferation. Laboratory-based models demonstrate that loss of NF1 is associated with resistance to endocrine therapy (ET), and emergence of NF1 mutations (NF1m) are correlated with progressive disease (PD) in circulating tumor DNA (ctDNA). While NF1m may diminish CDK4/6i susceptibility, a clear relationship has not been elucidated. The primary objective of this study was to characterize patient (pt) response to CDK4/6i in NF1m HR+/HER2- MBC. Methods: We identified 47 pts with NF1m via a database with one or more ctDNA samples sequenced at variable time-points as part of routine care for MBC. NF1m were categorized as pathogenic (p)NF1m or variants of uncertain significance (VUS) based on their associated Guardant report. We identified 27 pts with HR+/HER2- MBC and NF1m that received at least 1 line of CDK4/6i in the metastatic setting. Intrinsic resistance was defined as PD < 6 months on a CDK4/6i regimen, and acquired resistance was defined as PD >6 months. Pts with intrinsic resistance or acquired resistance and NF1m detected post-PD were categorized as having a resistance phenotype potentially driven by NF1m. Pts with NF1m detected prior to therapy and >6 months clinical response on a CDK4/6i were categorized as having NF1m tumors sensitive to CDK4/6i. Results: The NF1m cohort (n = 27) had 9 pts with pNF1m, while 18 pts expressed VUS. The median age at MBC diagnosis was 54 years, and 67% had visceral metastasis at ctDNA collection. Pts received a median of 1 prior line (range: 0 - 6) of ET or chemotherapy in the metastatic setting before CDK4/6i. Amongst pts with pathogenic variants (n = 9), we found 3 pts with pNF1m were intrinsically resistant to CDK4/6i. Acquired resistance was seen in 1 pt with pNF1m detected post-PD, and 2 pts had evidence of both acquired and subsequent intrinsic resistance to a later line of CDK4/6i. Overall, 67% (6/9) of pNF1m pts demonstrated a CDK4/6i resistance phenotype; mutant allele fraction (AF) ranged from 0.2% - 29.9%, and the mean maximum allele fraction (MAF) was 6.0%. Pre- and post-treatment samples were available on 3 pts with pNF1m, and 1 of these pts had an AF rise from 2.7% to 12.3% when comparing ctDNA pre- and post-CDK4/6i. ctDNA from 4 of 6 resistant tumors harbored other putative drivers including alterations in FGFR, KRAS, PTEN, and RB. We identified 2 counter-examples of pNF1m tumors sensitive to CDK4/6i. These pts expressed relatively low NF1m AF, ranging 0.1% - 0.5% with a mean MAF 0.3%. Another pNF1m pt had intrinsic resistance to initial CDK4/6i but was sensitive to later-line CDK4/6i. In the subgroup of pts with VUS-NF1m (n = 18), a more mixed picture of resistance and sensitivity was seen. 8 pts had intrinsic or acquired resistance, 8 pts had NF1m tumors sensitive to CDK4/6i, and 1 pt had evidence of both; 61% (n = 11) of pts expressed alterations in other resistance mediating genes. 1 pt stopped therapy due to toxicity rather than PD. Conclusions: Our work demonstrates that tumor expression of pNF1m may be associated with CDK4/6i resistance in pts with HR+/HER2- MBC, and allele fraction could be predictive of drug susceptibility. Tumors harboring VUS had varied sensitivity, suggesting that some of these mutations may not be pathogenic, and counter-examples of pNF1m MBC benefiting from CDK4/6i plus ET highlight the complexities in predicting drug response based on single gene alteration. Future effort is warranted to explore the potential impact of NF1 on CDK4/6i resistance, as well as the potential role for therapies targeting the MAPK pathway in this patient population. Citation Format: Maxwell R. Lloyd, Lianne Ryan, Arielle J. Medford, Jennifer C. Keenan, Laura M. Spring, Neelima Vidula, Beverly Moy, Dejan Juric, Leif Ellisen, Aditya Bardia, Seth A. Wander. Investigating NF1 Mutations in Circulating Tumor DNA of Patients with Hormone-receptor Positive (HR+) Breast Tumors Resistant to CDK4/6 Inhibition (CDK4/6i): A Retrospective Clinical Analysis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-13-07.

Aim. The aim of the paper was to evaluate the AgNOR parameters for the discrimination of benign from malignant breast tumors via a new approach - the total AgNOR area/nuclear area (TAA/NA). Material and methods. Three groups, consisting of control (n = 14), benign (n = 18) and malignant (n = 28) participants were included in the study. The AgNOR staining technique was performed and both mean AgNOR number and TAA/NA ratio were evaluated. Results. While the differences between the control and patient groups were statistically significant for AgNOR number (p < 0.001), it was not significant between the malignant group and the benign group for mean AgNOR number (p > 0.05). For the ratio of TAA/NA, the differences between the control and benign group (p < 0.001), control and malignant group (p < 0.001), and malignant and benign patient groups were significant. (p < 0.05). Conclusion. We consider that the evaluation of the TAA/NA rate, when compared with the AgNOR number, can be more sensitive and useful tool for distinguishing benign from the malignant breast lesions.

Background: The lack of sensitivity and specificity of existing diagnostic markers like Carbohydrate Antigen 15-3(CA15-3) and Carcinoembryonic antigen (CEA) in breast cancer stimulates the search for new biomarkers to improve diagnostic sensitivity especially in differentiating benign and malignant breast tumors. Expression of Human epididymal protein 4 (HE4) has been demonstrated in ductal carcinoma of the breast tissue. So we tried to evaluate serum HE4 levels as diagnostic marker in breast cancer patients and to comparatively assess serum HE4, CEA and CA15-3 in breast tumor patients both benign and malignant. Methods: Total 90 female subjects were included in the study. We selected 30 breast cancer cases (Malignant group) and 30 benign breast lump cases (Benign group) based on histopathology report. And other 30 were age matched apparently healthy controls (Control group). HE4, CEA and CA15-3 were analysed in serum samples of all subjects by Electrochemiluminiscence immunoassay method. Results: A significant difference in the median (IQR) of HE4 (pmol/l) was identified among malignant, benign and control groups {62.4(52.6-73.7) vs 49.3(39.8-57.4) vs 52.3(50.6-63.3) P=0.0009} respectively. The cutoff value for prediction of breast cancer was determined at >54.5 pmol/l for HE4, with a sensitivity of 73.3%, specificity of 65.3%, whereas cutoff value of CA 15-3 was >21.24 (U/ml) with a sensitivity of 56.7%, specificity of 74.5%. For CEA at cutoff value >0.99 (ng/ml) the sensitivity and specificity were 96.7 % and 62.7% respectively. AUC for HE4, CA15-3 and CEA were 0.725, 0.644 and 0.857 respectively. Conclusion: Our study demonstrated that serum levels of HE4 were significantly higher in malignant group compared to benign and control groups. There is no significant difference between HE4 levels between benign and control groups. These results indicate that HE4 appears as a useful and highly specific biomarker for breast cancer, which can differentiate between malignant and benign tumors.

In Iraq, breast cancer is considered one of the most widespread cancer types causing death in women due to changes in the genes that control cell growth and proliferation. KRAS gene plays a role in 30% of human cancers. This study aims to evaluate the expression of the KRAS gene and its role in women with breast tumours. A total of 120 women (60 women with breast tumours and 60 samples from apparently healthy women) were enrolled in this study to determine the expression of the KRAS gene. The RT-qPCR was used for this purpose. Fibroadenoma (FA) was the most common tumours, accounting for 53% of cases, followed by fibrocystic change (26%). Other benign tumours accounted for 20% of the cases; however, IDC is the most common type of invasive breast cancer, accounting for 70% of all breast cancers. Moreover, KRAS gene expression in women with breast tumours (benign and malignant) was not- significantly different from that seen in normal healthy women.

The upregulation of dihydroorotate dehydrogenase (DHODH) redox systems inside tumor cells provides a powerful shelter against lipid peroxidation (LPO), impeding ferroptosis-induced antitumor responses. To solve this issue, we report a strategy to block redox systems and enhance ferroptotic cancer cell death based on a layered double hydroxide (LDH) nanoplatform (siR/IONs@LDH) co-loaded with ferroptosis agent iron oxide nanoparticles (IONs) and the DHODH inhibitor (siR). siR/IONs@LDH is able to simultaneously release IONs and siR in a pH-responsive manner, efficiently generate toxic reactive oxygen species (ROS)

Preparation and antitumor application of nanogels are presented. This study provides a promising strategy to improve the synergistic antitumor effect of drugs.

Introduction:A study has been conducted on the incidence rates of different benign breast tumors ,their presentationand outcome beneficience of surgical procedures have been compared. Material And Methods:A total of 100 cases with benign breast mass, attending surgical department of RGKMCH and meeting the inclusion criterias were studied in the given time period. Results:Fibroadenoma predominates (94%) followed by Phyllodes tumour (2%), Intraductal papilloma (2%) and Lipoma(2%).The age group of 20 to 24 years showed the maximum number of cases. The all-benign breast tumours in the present study were managed in accordance with the types of tumour. All the fibroadenomas were excised locally. Conclusion:Fibroadenoma is the commonest type of benign breast tumours than other types. . The treatment of benign breast tumours are simple excision and sometimes may require simple mastectomy.

Introduction Breast cancer is the most common cancer in women in India and accounts for 14% of all cancers in women. Rise in mortality is due to lack of awareness and proper screening. Mammography and presently available serum biomarkers have low sensitivity and specificity. In our quest to identify a better biomarker, we studied mammaglobin (MAM) in patients with breast cancer and benign breast tumors. Aim To evaluate serum mammaglobin in breast cancer patients and compare it with benign breast tumor patients and healthy controls. To compare it with existing biomarkers serum carcinoembryonic antigen (CEA) and cancer antigen 15–3 (CA 15–3). Materials and methods: This is a cross-sectional, case–control study of 77 subjects, of which 27 were breast cancer patients, 20 benign breast tumor patients, and 30 healthy controls. Serum CEA and CA15–3 were estimated by electrochemiluminescence immunoassay (ECLIA) and mammaglobin (MAM) by enzyme-linked immunosorbent assay (ELISA). Results Mammaglobin and CEA levels were elevated in breast cancer patients, followed by benign breast tumors when compared with controls (P Conclusion Mammaglobin proved to be an efficacious biomarker in diagnosing breast cancer.

Novel approaches are required to address the urgent need to develop lipid-based carriers of paclitaxel (PTX) and other hydrophobic drugs for cancer chemotherapy. Carriers based on cationic liposomes (CLs) with fluid (i.e., chain-melted) membranes (e.g., EndoTAG-1®) have shown promise in preclinical and late-stage clinical studies. Recent work found that the addition of a cone-shaped poly(ethylene glycol)-lipid (PEG-lipid) to PTX-loaded CLs (CLsPTX) promotes a transition to sterically stabilized, higher-curvature (smaller) nanoparticles consisting of a mixture of PEGylated CLsPTX and PTX-containing fluid lipid nanodiscs (nanodiscsPTX). These CLsPTX and nanodiscsPTX show significantly improved uptake and cytotoxicity in cultured human cancer cells at PEG coverage in the brush regime (10 mol% PEG-lipid). Here, we studied the PTX loading, in vivo circulation half-life, and biodistribution of systemically administered CLsPTX and nanodiscsPTX and assessed their ability to induce apoptosis in triple-negative breast cancer-bearing immunocompetent mice. We focused on fluid rather than solid lipid nanodiscs because of the significantly higher solubility of PTX in fluid membranes. At 5 and 10 mol% of a PEG-lipid (PEG5K-lipid, molecular weight of PEG 5000 g/mol), the mixture of PEGylated CLsPTX and nanodiscsPTX was able to incorporate up to 2.5 mol% PTX without crystallization for at least 20 h. Remarkably, compared to preparations containing 2 and 5 mol% PEG5K-lipid (with the PEG chains in the mushroom regime), the particles at 10 mol% (with PEG chains in the brush regime) showed significantly higher blood half-life, tumor penetration and proapoptotic activity. Our study suggests that increasing the PEG coverage of CL-based drug nanoformulations can improve their pharmacokinetics and therapeutic efficacy., This research study was supported by the National Institutes of Health under award R01GM130769 (CRS, KKE, WF; mechanistic studies on developing lipid nanoparticles for drug delivery), the European Regional Development Fund (TT, Project No. 2014-2020.4.01.15-0012), the Estonian Research Council (TT, grants PRG230 and EAG79; PS, grant PSG38; LSG, grant MOBJD11), EuronanomedII projects ECM-CART and iNanoGun (TT), H2020 MSCA-RISE project Oxigenated (TT), and the Spanish Ministry of Science and Innovation grants RYC2020-028754-I and PID2021-122364OA-I00 (PS). Partial support was provided by the US National Science Foundation (NSF) under Award DMR-1807327 (CRS; kinetic phase behavior of cationic vesicles with incorporated hydrophobic molecules).

Metastasis of breast cancer is key to poor prognosis and high mortality. However, the excess reactive oxygen species (ROS) and inflammatory response induced by photothermal therapy (PTT) further aggravate tumor metastasis. Meanwhile, the hypoxic tumor microenvironment promotes tumor cells to metastasize to distant organs. Herein, the intrinsic limitations of PTT for metastatic tumor have been addressed by fabricating polyethylene glycol modified iridium tungstate (IrWO

Background: In Western countries, middle-aged women are more vulnerable to breast cancer. Globally, almost a million new cases were identified in 1998. One in 12 women in England and Wales will get the disease at some point.1 Even 5,000 years after it was first reported, the etiology of breast cancer is still unclear, and effective preventative measures are even further off. Aim: To characterize the varied ways in which breast cancer has presented itself among patients at Bahawal Victoria Hospital in Bahawalpur. Methods: This investigation employed a descriptive case series research design. This research was conducted at Bahawal Victoria Hospital's Surgery Department in Bahawalpur (Pakistan). From March 13th, 2020 through March 12th, 2021, the study was conducted (12 months). With their assent, 100 women with definite cases of breast cancer were enrolled in the study. Results: Cancer of the breast most commonly affected women between the ages of 31 and 50 (59%). Seventy-six patients arrived from the outlying rural areas of Bahawalpur and the neighboring districts. Only 18 patients had completed high school after 10 years and 5 patients were discovered to be college graduates. The single rate was 12%, with 12 patients. Eighty-one percent of patients reported having a breast lump. 56% of breast cancers involve the left breast, while 43% involve the right. One patient alone had breast cancer that had spread to both of her breasts. Illness duration varied from 1 month to 5 years. Stage III was the most prevalent presentation, with 46 instances, and Stage IV was the least common, with 16 patients. The histological hallmark most frequently attested by examination of slides was infiltrating ductal carcinoma, and this was the case in 87% of the cases. Conclusion: Breast cancer is very common cancer in the females, and most commonly it presented as a lump in the breast, because of some social aspects, lack of awareness, poverty, no proper screening programs and above all the fear of diagnosis, females try to hide this problem and often it presented at late and more advance stage. Keywords: Breast, Nipple, Cancer, Lump, Surgery, Tumor

Introduction. Benign mammary gland tumors constitute a group of heterogeneous diseases with a complex clinical and morphological structure that complicates timely diagnosis and terminological designation of pathological processes. They are of great interest because of their possible background for oncologic pathology. The most widespread disease is mastopathy, its occurrence rate in the population reaches 40%. The incidence of mastopathies increases by the age of 45 years, and then tends to decrease in the pre- and postmenopausal periods. The purpose of the review was to evaluate and analyze the literature data on the presented problem in recent years. Materials and methods. Publications of domestic and foreign authors on benign breast neoplasms and risk factors of this pathology over the past 20 years have been included in the article. Literature search was performed in the systems Scopus, Web of Science, PubMed, Elibrary. Results and discussion. Etiopathogenetic factors in patients with benign mammary gland tumors play a paramount role, substantiating the necessity of prognostication and prevention of the disease. Risk factors for these diseases include hereditary, hormonal, neuropsychological, reproductive data, age, lactation, inflammation, trauma, smoking, and others. Conclusion. The current dynamic of increasing the incidence of benign mammary tumors has been noted, but no specific risk factors for this group of diseases have been identified, as they are multifactorial, associated with genetic causes, somatic health data, and environmental influences. Not all women are equally at risk of developing breast diseases, the reasons characterizing the individual propensity for this pathology have been identified. The risk factors do not cause the development of the disease, but considerably increase its probability. The study of predisposing risk factors for the development of tumor processes in the mammary glands in order to diagnose them early gives an opportunity to improve the results and prognosis of treatment.

Poly(ADP-ribose) polymerase (PARP) inhibitors have demonstrated promising clinical activity in multiple cancers. However, resistance to PARP inhibitors remains a substantial clinical challenge. In the present study, we report that anaplastic lymphoma kinase (ALK) directly phosphorylates CDK9 at tyrosine-19 to promote homologous recombination (HR) repair and PARP inhibitor resistance. Phospho-CDK9-Tyr19 increases its kinase activity and nuclear localization to stabilize positive transcriptional elongation factor b and activate polymerase II-dependent transcription of HR-repair genes. Conversely, ALK inhibition increases ubiquitination and degradation of CDK9 by Skp2, an E3 ligase. Notably, combination of US Food and Drug Administration-approved ALK and PARP inhibitors markedly reduce tumor growth and improve survival of mice in PARP inhibitor-/platinum-resistant tumor xenograft models. Using human tumor biospecimens, we further demonstrate that phosphorylated ALK (p-ALK) expression is associated with resistance to PARP inhibitors and positively correlated with p-Tyr19-CDK9 expression. Together, our findings support a biomarker-driven, combinatorial treatment strategy involving ALK and PARP inhibitors to induce synthetic lethality in PARP inhibitor-/platinum-resistant tumors with high p-ALK–p-Tyr19-CDK9 expression.

Objective: To analyze the application of ultrasound-guided thoracic nerve block (TNB) in the operation of benign breast tumors. Methods: A retrospective analysis was conducted on 69 patients who underwent resection of benign breast tumors (fibroma, segment) in the Maternity and Child Care Center of Qinhuangdao from January 2021 to June 2022. Among them, 33 patients who received TNB were assigned to an observation group, and 36 patients who received local infiltration anesthesia were assigned to a control group. The heart rate (HR) and systolic blood pressure (SBP) and diastolic blood pressure (DBP) of patients were recorded before anesthesia (T0), at skin incision (T1), at 0.5 h after operation (T2) and before leaving the operating room (T3). We also recorded the operation indexes, comprising operation time, total propofol dosage administered during operation, anesthesia recovery time and extubation time. The visual analogue scale (VAS) score was evaluated at 0.5, 2, 4 and 6 h after the operation. The two groups were also compared in terms of the levels of immunoglobulin (Ig) A, IgG, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The postoperative adverse reactions in the two groups were statistically analyzed. Results: Compared with the observation group, the control group experienced a longer operation time, anesthesia recovery time and extubation time and consumed more propofol (P < 0.001). At T0 and T1, the two groups were not notably different in SBP, DBP and HR (P > 0.05), but at T2 and T3, the control group showed higher SBP, DBP and HR than the observation group (P < 0.001). The control group exhibited notably higher VAS scores than the observation group (P < 0.001). Before operation, the differences in the levels of IgA, IgG, IL-6 and TNF-α were not significantly different between the two groups (P > 0.05), while after operation and at 24 h after operation, the control group showed higher levels of IgA, IgG, IL-6 and TNF-α in comparison to the observation group (P < 0.01). The incidences of adverse reactions were not significantly different between the two groups (P > 0.05). Conclusion: Ultrasound-guided TNB can substantially reduce both the operation time and the postoperative pain in patients with benign breast tumors, without increasing the incidence of adverse reactions.

PURPOSE: To develop optoacoustic, spectrally distinct, actively targeted gold nanoparticle–based near-infrared probes (trastuzumab [TRA], TRA-Aurelia-1, and TRA-Aurelia-2) that can be individually identifiable at multispectral optoacoustic tomography (MSOT) of human epidermal growth factor receptor 2 (HER2)–positive breast tumors. MATERIALS AND METHODS: Gold nanoparticle–based near-infrared probes (Aurelia-1 and 2) that are optoacoustically active and spectrally distinct for simultaneous MSOT imaging were synthesized and conjugated to TRA to produce TRA-Aurelia-1 and 2. Freshly resected human HER2-positive (n = 6) and HER2-negative (n = 6) triple-negative breast cancer tumors were treated with TRA-Aurelia-1 and TRA-Aurelia-2 for 2 hours and imaged with MSOT. HER2-expressing DY36T2Q cells and HER2-negative MDA-MB-231 cells were implanted orthotopically into mice (n = 5). MSOT imaging was performed 6 hours following the injection, and the Friedman test was used for analysis. RESULTS: TRA-Aurelia-1 (absorption peak, 780 nm) and TRA-Aurelia-2 (absorption peak, 720 nm) were spectrally distinct. HER2-positive human breast tumors exhibited a significant increase in optoacoustic signal following TRA-Aurelia-1 (28.8-fold) or 2 (29.5-fold) (P = .002) treatment relative to HER2-negative tumors. Treatment with TRA-Aurelia-1 and 2 increased optoacoustic signals in DY36T2Q tumors relative to those in MDA-MB-231 controls (14.8-fold, P < .001; 20.8-fold, P < .001, respectively). CONCLUSION: The study demonstrates that TRA-Aurelia 1 and 2 nanoparticles operate as a spectrally distinct HER2 breast tumor–targeted in vivo optoacoustic agent. Keywords: Molecular Imaging, Nanoparticles, Photoacoustic Imaging, Breast Cancer Supplemental material is available for this article. © RSNA, 2023

Background: Estrogen receptor-positive (ER+) breast cancer is the most diagnosed subtype, with aromatase inhibitors (AIs) being one of the therapeutic drug types used in the clinic. However, endocrine resistance may develop after prolonged treatment, and different approaches, such as combining endocrine and targeted therapies, have been applied. Recently, we demonstrated that cannabidiol (CBD) induces anti-tumor actions in ER+ breast cancer cells by targeting aromatase and ERs. Considering this, we studied, in vitro, whether CBD when combined with AIs could improve their effectiveness. Methods: MCF-7aro cells were used and the effects on cell viability and on the modulation of specific targets were investigated. Results: CBD when combined with anastrozole (Ana) and letrozole (Let) caused no beneficial effect in comparison to the isolated AIs. In contrast, when combined with the AI exemestane (Exe), CBD potentiated its pro-cell death effects, abolished its estrogen-like effect, impaired ERα activation, and prevented its oncogenic role on the androgen receptor (AR). Moreover, this combination inhibited ERK1/2 activation, promoting apoptosis. The study of the hormonal microenvironment suggests that this combination should not be applied in early stages of ER+ breast tumors. Conclusions: Contrary to Ana and Let, this study highlights the potential benefits of combining CBD with Exe to improve breast cancer treatment and opens up the possibility of new therapeutic approaches comprising the use of cannabinoids.

Autophagy is activated in response to cellular stressors and mediates lysosomal degradation and recycling of cytoplasmic material and organelles as a temporary cell survival mechanism. Defective autophagy is implicated in human pathology, as disruption of protein and organelle homeostasis enables disease-promoting mechanisms such as toxic protein aggregation, oxidative stress, genomic damage, and inflammation. We previously showed that autophagy-defective immortalized mouse mammary epithelial cells are susceptible to metabolic stress, DNA damage, and genomic instability. We now report that autophagy deficiency is associated with endoplasmic reticulum (ER) and oxidative stress, and with deregulation of p62-mediated keratin homeostasis in mammary cells, allograft tumors, and mammary tissues from genetically engineered mice. In human breast tumors, high phospho(Ser73)-K8 levels are inversely correlated with Beclin 1 expression. Thus, autophagy preserves cellular fitness by limiting ER and oxidative stress, a function potentially important in autophagy-mediated suppression of mammary tumorigenesis. Furthermore, autophagy regulates keratin homeostasis in the mammary gland via a p62-dependent mechanism. High phospho(Ser73)-K8 expression may be a marker of autophagy functional status in breast tumors and, as such, could have therapeutic implications for breast cancer patients. Mol Cancer Res; 8(6); 873–84. ©2010 AACR.

Cancer-associated fibroblasts (CAFs) are generally associated with poor clinical outcome. CAFs support tumor growth in a variety of ways and can suppress antitumor immunity and response to immunotherapy. However, a precise understanding of CAF contributions to tumor growth and therapeutic response is lacking. Discrepancies in this field of study may stem from heterogeneity in the composition and function of fibroblasts in the tumor microenvironment. Furthermore, it remains unclear whether CAFs directly interact with and suppress T cells. Here, mouse and human breast tumors were used to examine stromal cells expressing fibroblast activation protein (FAP), a surface marker for CAFs. Two discrete populations of FAP+ mesenchymal cells were identified on the basis of podoplanin (PDPN) expression: a FAP+PDPN+ population of CAFs and a FAP+PDPN− population of cancer-associated pericytes (CAPs). Although both subsets expressed extracellular matrix molecules, the CAF transcriptome was enriched in genes associated with TGFβ signaling and fibrosis compared with CAPs. In addition, CAFs were enriched at the outer edge of the tumor, in close contact with T cells, whereas CAPs were localized around vessels. Finally, FAP+PDPN+ CAFs suppressed the proliferation of T cells in a nitric oxide–dependent manner, whereas FAP+PDPN− pericytes were not immunosuppressive. Collectively, these findings demonstrate that breast tumors contain multiple populations of FAP-expressing stromal cells of dichotomous function, phenotype, and location.

BRCA1-associated breast tumors display loss of BRCA1 and frequent somatic mutations of PTEN and TP53. Here we describe the analysis of BRCA1, PTEN, and p53 at the single cell level in 55 BRCA1-associated breast tumors and computational methods to predict the relative temporal order of somatic events, on the basis of the frequency of cells with single or combined alterations. Although there is no obligatory order of events, we found that loss of PTEN is the most common first event and is associated with basal-like subtype, whereas in the majority of luminal tumors, mutation of TP53 occurs first and mutant PIK3CA is rarely detected. We also observed intratumor heterogeneity for the loss of wild-type BRCA1 and increased cell proliferation and centrosome amplification in the normal breast epithelium of BRCA1 mutation carriers. Our results have important implications for the design of chemopreventive and therapeutic interventions in this high-risk patient population.Significance: Defining the temporal order of tumor-driving somatic events is critical for early detection, risk stratification, and the design of chemopreventive therapies. Our combined experimental and computational approach reveal that the loss of wild-type BRCA1 may not be the first event in the majority of BRCA1-associated breast tumors and may not be present in all cancer cells within tumors. Cancer Discov; 2(6); 503–11. ©2012 AACR.This article is highlighted in the In This Issue feature, p. 473

HER2+ breast tumors have been shown to express elevated levels of PARP1 protein. Yet, the mechanism by which PARP1 is upregulated in HER2+ breast cancer is unknown. Here, knockdown of HER2 (ERBB2) in HER2+ breast cancer cells resulted in a reduction in PARP1 protein. Conversely, ectopic overexpression of HER2 in a non-HER2–overexpressing cell line resulted in increased PARP1 protein levels. Alterations in HER2 expression had no significant effect on PARP1 transcript levels. Instead, HER2 mRNA status was inversely correlated with let-7a miRNA levels in breast cancer cells. Ectopic expression of let-7a miRNA resulted in downregulation of PARP1 protein, whereas expression of the let-7a anti-miRNA increased PARP1 protein. Furthermore, luciferase assays demonstrate that let-7a regulates PARP1 via its 3′UTR. Importantly, let-7a was significantly lower in human HER2+ breast tumors compared with HER2− breast tumors and inversely correlated with PARP1 protein levels. Finally, HER2+ breast cancer cells exhibited similar cytotoxicity to ectopic let-7a expression as the PARP inhibitor veliparib (ABT-888). Collectively, these results reveal that increased PARP1 expression in HER2+ breast cancers is regulated by the let-7a miRNA, and that let-7a is a potential strategy to suppress PARP1 activity.Implications: This study reports the novel findings that HER2 increases PARP1 protein via suppression of the let-7a miRNA, which regulates the PARP1 3′-UTR. Moreover, HER2 status correlates with high PARP1 and low let-7a in breast cancer clinical specimens. Mol Cancer Res; 15(3); 340–7. ©2016 AACR.

ObjectivesTo assess DWI for tumor visibility and breast cancer detection by the addition of different synthetic b-values.MethodsEighty-four consecutive women who underwent a breast-multiparametric-MRI (mpMRI) with enhancing lesions on DCE-MRI (BI-RADS 2–5) were included in this IRB-approved retrospective study from September 2018 to March 2019. Three readers evaluated DW acquired b-800 and synthetic b-1000, b-1200, b-1500, and b-1800 s/mm2images for lesion visibility and preferred b-value based on lesion conspicuity. Image quality (1–3 scores) and breast composition (BI-RADS) were also recorded. Diagnostic parameters for DWI were determined using a 1–5 malignancy score based on qualitative imaging parameters (acquired + preferred synthetic b-values) and ADC values. BI-RADS classification was used for DCE-MRI and quantitative ADC values + BI-RADS were used for mpMRI.ResultsSixty-four malignant (average = 23 mm) and 39 benign (average = 8 mm) lesions were found in 80 women. Although b-800 achieved the best image quality score, synthetic b-values 1200–1500 s/mm2were preferred for lesion conspicuity, especially in dense breast. b-800 and synthetic b-1000/b-1200 s/mm2values allowed the visualization of 84–90% of cancers visible with DCE-MRI performing better than b-1500/b-1800 s/mm2. DWI was more specific (86.3% vs 65.7%,p< 0.001) but less sensitive (62.8% vs 90%,p< 0.001) and accurate (71% vs 80.7%,p= 0.003) than DCE-MRI for breast cancer detection, where mpMRI was the most accurate modality accounting for less false positive cases.ConclusionThe addition of synthetic b-values enhances tumor conspicuity and could potentially improve tumor visualization particularly in dense breast. However, its supportive role for DWI breast cancer detection is still not definite.Key Points•The addition of synthetic b-values (1200–1500 s/mm2) to acquired DWI afforded a better lesion conspicuity without increasing acquisition time and was particularly useful in dense breasts.•Despite the use of synthetic b-values, DWI was less sensitive and accurate than DCE-MRI for breast cancer detection.•A multiparametric MRI modality still remains the best approach having the highest accuracy for breast cancer detection and thus reducing the number of unnecessary biopsies.

Several clinical trials have demonstrated the benefit of adding pertuzumab to trastuzumab plus neoadjuvant chemotherapy in the treatment of human epidermal growth factor receptor 2 (HER2)-positive breast cancer. The comparison of outcomes between nonrandomized groups of patients who received similar treatments in routine practice remains difficult. The present study aimed to evaluate the pathological complete response (pCR) rates achieved with pertuzumab among patients in routine clinical care in Peru using real-world data. The definition of pCR used was the absence of residual invasive cancer from the complete resected breast specimen and all sampled regional lymph nodes following completion of neoadjuvant systemic therapy. A total of 44 patients with non-metastatic HER2-positive breast cancer (stages II and III) treated with pertuzumab in the neoadjuvant setting and who underwent surgery at three private clinics in Lima (Peru) were retrospectively evaluated. The pCR was the efficacy endpoint and it was determined and compared with the results from other clinical trials. Furthermore, safety data were described. The median age was 44 years (interquartile range, 39.5-50.5 years) and 65.9% of patients were premenopausal. Regarding the clinical stage, 56.8% were IIA/IIB and 36.4% were IIIA/IIIB/IIIC. All treatment schemes included concurrent trastuzumab. The patients' treatment comprised neoadjuvant therapy of docetaxel/trastuzumab/pertuzumab (THP) with a median of 4 cycles in 30 patients (68.2%) or docetaxel/trastuzumab/pertuzumab/carboplatin (THPCarb) with a median of 6 cycles in 14 patients (31.8%). In total, 70.5% of patients experienced pCR; among hormone receptor-negative cases, 75.0% achieved pCR and in tumors expressing hormone receptors, the rate of pCR was 66.7%. Of those patients subjected to neoadjuvant treatment with THP, 66.7% (20/30) achieved pCR, whereas 78.6% (11/14) of patients who received THPCarb had a pCR. The incidence of drug-related adverse events was 59.1% and in none of the patients, administration was discontinued due to toxicity. The present results of Peruvian patients with HER2 breast cancer treated according to clinical routine demonstrated that dual blockade of HER2 with trastuzumab and pertuzumab in the neoadjuvant setting achieved high rates of pCR even in hormone receptor-positive patients. These results are consistent with those of randomized controlled trials, with a good safety profile.

Breast cancer is one of the most common types of cancer among Iraqi women. MRI has been used in the detection of breast tumors for its efficient performance in the diagnosis process providing high accuracy. In this paper, breast MRI image data from 89 patients were classified using GLCM and CNN feature extraction methods. Four models were evaluated consisting of GLCM, CNN, combined GLCM and CNN features based models. The statistical ANOVA feature selection method was used to reduce the redundant features. The reduced feature subset was fed to CNN classifier for obtaining either normal or abnormal breast images. The proposed method was assessed in terms of accuracy, precision, recall and F1-score. The model provided 100% classification accuracy.

Context and objective. Benign breast tumors (BBT) are poorly documented in our country. The aim of the present study was to describe the clinical and anatomopathological profile of BBT. Methods.This was a series of cases of BBT followed at the Kinshasa University Hospital (CUK) between 1996 and 2020. The variables of interest included socio-demographic profile, gyneco-obstetrical history, complaints and clinical aspects for the patients; and senological, anatomopathological, therapeutic aspects and associated factors for the tumors. Multivariate logistic regression method was used to search for factors associated with BBT. Results. Out of 682 medical records collected for senological problems, 231 cases had a presumptive diagnosis of BBT and only 70 cases were histologically confirmed, i.e. a frequency of BBT of 10.2%. Their mean age was 27.8 ± 13.8 years, 76.5% were nulliparous, 17.6 % had breast-fed. Fibroadenoma was more frequent (68.5%) followed by fibrocystic disease (20.0%). In univariate analysis, age less than 40 years [crude OR 4.00 (1.18-13.54), p=0.026], nulliparity [5.17 (1.44-18.57), p=0.012] and lack of breastfeeding [0.16 (0.04- 0.63), p=0.009] were associated with fibroadenoma while age greater than 40 years [4.50 (1.23-16.45); p=0.023], marriage [5.22 (1.47-18.55); p=0.011], multiparity [5.89 (1.53- 22.63); p=0.010)] and breastfeeding [6(1.55- 23.30); p=0.010)] to fibrocystic disease. No factor emerged as an independent determinant of BBT. Conclusion. BBT, although poorly diagnosed in this tertiary institution, shows some similarity with data in the literature French Abstract Contexte et objectif Les données sur les tumeurs bénignes du sein (TBS) sont peu documentées dans nos contrées. La présente étude avait pour objectif de décrire le profil clinique et anatomopathologique des TBS. Méthodes) aspects cliniques et, pour les tumeurs : les aspects sénologique, anatomopathologique, thérapeutique et les facteurs associés. Nous avons recouru à la méthode de régression logistique multi variée pour rechercher les facteurs associés aux TBS. Résultats Sur 682 dossiers médicaux colligés pour problems sénologiques, 231 cas portaient le diagnostic présomptif de TBS et seulement 70 cas étaient confirmés histologiquement soit une fréquence des TBS de 10,2 %. Leur âge moyen était de 27,8 ± 13,8 ans, 76,5 % étaient nullipares, 17,6 % avaient allaité. Le fibroadénome était plus fréquent (68,5%) suivi de la maladie fibrokystique (20,0 %). En analyse univariée, l’âge inférieur à 40 ans [OR brut 4,00 (1,18-13,54), p=0,026], la nulliparité [5,17 (1,44-18,57), p=0,012] et l’absence d’allaitement [0,16 (0,04-0,63), p=0,009] étaient associés au fibroadénome tandis que l’âge supérieur à 40 ans [4,50 (1,23-16,45); p=0,023], le mariage [5,22 (1,47-18,55); p=0,011], la multiparité [5,89 (1,53-22,63); p=0,010)] et l’allaitement [6(1,55-23,30) ; p=0,010)] à la maladie fibrokystique. Aucun facteur n’a émergé comme determinant indépendant de TBS. Conclusion Les TBS quoique peu diagnostiquées dans cette institution tertiaire présentent une certaine similarité avec les données de la littérature Mots-clés : Tumeurs bénignes du sein, épidémiologie, clinique, histopathologie

Spontaneous tumors that arise in genetically engineered mice recapitulate the natural tumor microenvironment and tumor-immune coevolution observed in human cancers, providing a more physiologically relevant preclinical model relative to implanted tumors. Similar to many cancer patients, oncogene-driven spontaneous tumors are often resistant to immunotherapy, and thus novel agents that can effectively promote antitumor immunity against these aggressive cancers show considerable promise for clinical translation, and their mechanistic assessment can broaden our understanding of tumor immunology. In this study, we performed extensive immune profiling experiments to investigate how tumor-targeted TLR9 stimulation remodels the microenvironment of spontaneously arising tumors during an effective antitumor immune response. To model the clinical scenario of multiple tumor sites, we used MMTV-PyMT transgenic mice, which spontaneously develop heterogeneous breast tumors throughout their 10 mammary glands. We found that i.v. administration of a tumor-targeting TLR9 agonist, referred to as PIP-CpG, induced a systemic T cell–mediated immune response that not only promoted regression of existing mammary tumors, but also elicited immune memory capable of delaying growth of independent newly arising tumors. Within the tumor microenvironment, PIP-CpG therapy initiated an inflammatory cascade that dramatically amplified chemokine and cytokine production, prompted robust infiltration and expansion of innate and adaptive immune cells, and led to diverse and unexpected changes in immune phenotypes. This study demonstrates that effective systemic treatment of an autochthonous multisite tumor model can be achieved using a tumor-targeted immunostimulant and provides immunological insights that will inform future therapeutic strategies.

IntroductionIncidence of estrogen receptor (ER)-negative breast cancer, an aggressive tumor subtype associated with worse prognosis, is higher among African American/Black women than other US racial and ethnic groups. The reasons for this disparity remain poorly understood but may be partially explained by differences in the epigenetic landscape.MethodsWe previously conducted genome-wide DNA methylation profiling of ER- breast tumors from Black and White women and identified a large number of differentially methylated loci (DML) by race. Our initial analysis focused on DML mapping to protein-coding genes. In this study, motivated by increasing appreciation for the biological importance of the non-protein coding genome, we focused on 96 DMLs mapping to intergenic and noncoding RNA regions, using paired Illumina Infinium Human Methylation 450K array and RNA-seq data to assess the relationship between CpG methylation and RNA expression of genes located up to 1Mb away from the CpG site. ResultsTwenty-three (23) DMLs were significantly correlated with the expression of 36 genes (FDRHOXB2. Increased methylation at this CpG correlated with decreased expression of HOXB2 (Rho=-0.74, FDRHOXB/HOXB-AS genes. Analysis of an independent set of 207 ER- breast cancers from TCGA similarly confirmed hypermethylation at cg20401567 and reduced HOXB2 expression in tumors from Black versus White women (Rho=-0.75, FDRDiscussionOur findings indicate that epigenetic differences in ER- tumors between Black and White women are linked to altered gene expression and may hold functional significance in breast cancer pathogenesis.

Immune checkpoint blockade (ICB) is currently approved for patients with triple-negative breast cancer (TNBC), whereas responses to ICB are also observed in a small subgroup of Estrogen Receptor (ER)-positive breast cancer. The cut-off for ER-positivity (≥1%) is based on likelihood of endocrine treatment response, but ER-positive breast cancer represents a very heterogeneous group. This raises the question whether selection based on ER-negativity should be revisited to select patients for ICB treatment in the context of clinical trials. Stromal tumor-infiltrating lymphocytes (sTILs) and other immune parameters are higher in TNBC compared to ER-positive breast cancer, but it is unknown whether lower ER levels are associated with more inflamed tumor microenvironments (TME). We collected a consecutive series of primary tumors from 173 HER2-negative breast cancer patients, enriched for tumors with ER expression between 1 and 99% and found levels of stromal TILs, CD8 + T cells, and PD-L1 positivity in breast tumors with ER 1–9% and ER 10–50% to be comparable to tumors with ER 0%. Expression of immune-related gene signatures in tumors with ER 1–9% and ER 10–50% was comparable to ER 0%, and higher than in tumors with ER 51–99% and ER 100%. Our results suggest that the immune landscape of ER low tumors (1–9%) and ER intermediate tumors (10–50%) mimic that of primary TNBC.

Somatic mutational profiling is increasingly being used to identify potential targets for breast cancer. However, limited tumor-sequencing data from Hispanic/Latinas (H/L) are available to guide treatment. To address this gap, we performed whole exome sequencing (WES) and RNA-sequencing on 146 tumors and WES of matched germline DNA from 140 H/L women in California. Tumor intrinsic subtype, somatic mutations, copy number alterations, and expression profiles of the tumors were characterized and compared to data from tumors of non-Hispanic White (White) women in The Cancer Genome Atlas (TCGA). Eight genes were significantly mutated in the H/L tumors including PIK3CA, TP53, GATA3, MAP3K1, CDH1, CBFB, PTEN, and RUNX1; the prevalence of mutations in these genes was similar to that observed in White women in TCGA. Four previously reported COSMIC mutation signatures (1, 2, 3, 13) were found in the H/L dataset, along with signature 16 that has not been previously reported in other breast-cancer datasets. Recurrent amplifications were observed in breast-cancer drivers including MYC, FGFR1, CCND1, and ERBB2, as well as a recurrent amplification in 17q11.2 associated with high KIAA0100 gene expression that has been implicated in breast-cancer aggressiveness. In conclusion, this study identified a higher prevalence of COSMIC signature 16 and a recurrent copy number amplification affecting expression of KIAA0100 in breast tumors from H/L compared to White women. These results highlight the necessity of studying under-represented populations.

PurposeTo evaluate the potential of the texture features extracted from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) intratumoral subregions to distinguish benign from malignant breast tumors.Materials and MethodsA total of 299 patients with pathologically verified breast tumors who underwent breast DCE-MRI examination were enrolled in this study, including 124 benign cases and 175 malignant cases. The whole tumor area was semi-automatically segmented on the basis of subtraction images of DCE-MRI in Matlab 2018b. According to the time to peak of the contrast agent, the whole tumor area was partitioned into three subregions: early, moderate, and late. A total of 467 texture features were extracted from the whole tumor area and the three subregions, respectively. Patients were divided into training (n = 209) and validation (n = 90) cohorts by different MRI scanners. The least absolute shrinkage and selection operator (LASSO) method was used to select the optimal feature subset in the training cohort. The Kolmogorov-Smirnov test was first performed on texture features selected by LASSO to test whether the samples followed a normal distribution. Two machine learning methods, decision tree (DT) and support vector machine (SVM), were used to establish classification models with a 10-fold cross-validation method. The performance of the classification models was evaluated with receiver operating characteristic (ROC) curves.ResultsIn the training cohort, the areas under the ROC curve (AUCs) for the DT_Whole model and SVM_Whole model were 0.744 and 0.806, respectively. In contrast, the AUCs of the DT_Early model (P = 0.004), DT_Late model (P = 0.015), SVM_Early model (P = 0.002), and SVM_Late model (P = 0.002) were significantly higher: 0.863 (95% CI, 0.808–0.906), 0.860 (95% CI, 0.806–0.904), 0.934 (95% CI, 0.891–0.963), and 0.921 (95% CI, 0.876–0.954), respectively. The SVM_Early model and SVM_Late model achieved better performance than the DT_Early model and DT_Late model (P = 0.003, 0.034, 0.008, and 0.026, respectively). In the validation cohort, the AUCs for the DT_Whole model and SVM_Whole model were 0.670 and 0.708, respectively. In comparison, the AUCs of the DT_Early model (P = 0.006), DT_Late model (P = 0.043), SVM_Early model (P = 0.001), and SVM_Late model (P = 0.007) were significantly higher: 0.839 (95% CI, 0.747–0.908), 0.784 (95% CI, 0.601–0.798), 0.890 (95% CI, 0.806–0.946), and 0.865 (95% CI, 0.777–0.928), respectively.ConclusionThe texture features from intratumoral subregions of breast DCE-MRI showed potential in identifying benign and malignant breast tumors.

A strong correlation between NOS2 and COX2 tumor expression and poor clinical outcomes in ER-breast cancer has been established. However, mechanisms of tumor induction of these enzymes are unclear. Analysis of The Cancer Genome Atlas (TCGA) revealed correlations between NOS2 and COX2 expression and Th1 cytokines. Herein, single cell RNAseq analysis of TNBC cells shows potent NOS2 and COX2 induction by IFNγ combined with IL1β or TNFα. Given that IFNγ is secreted by cytolytic lymphocytes, which improve clinical outcomes, this role of IFNγpresents a dichotomy. To explore this conundrum, tumor NOS2, COX2, and CD8+T cells were spatially analyzed in aggressive ER-, TNBC, and HER2+ breast tumors. High expression and clustering of NOS2-expressing tumor cells occurred at the tumor/stroma interface in the presence of stroma-restricted CD8+T cells. High expression and clustering of COX2-expressing tumor cells extended into immune desert regions in the tumor core where CD8+T cell penetration was limited or absent. Moreover, high NOS2-expressing tumor cells were proximal to areas with increased satellitosis suggestive of cell clusters with a higher metastatic potential. Furtherin vitroexperiments revealed that IFNγ+IL1β/TNFα increased elongation and migration of treated tumor cells. This spatial analysis of the tumor microenvironment provides important insight of distinct neighborhoods where stroma-restricted CD8+T cells exist proximal to NOS2-expressing tumor niches that could have increased metastatic potential.

Establishing commensal dysbiosis, defined as an inflammatory gut microbiome with low biodiversity, before breast tumor initiation, enhances early dissemination of hormone receptor–positive (HR+) mammary tumor cells. Here, we sought to determine whether cellular changes occurring in normal mammary tissues, before tumor initiation and in response to dysbiosis, enhanced dissemination of HR+ tumors. Commensal dysbiosis increased both the frequency and profibrogenicity of mast cells in normal, non–tumor-bearing mammary tissues, a phenotypic change that persisted after tumor implantation. Pharmacological and adoptive transfer approaches demonstrated that profibrogenic mammary tissue mast cells from dysbiotic animals were sufficient to enhance dissemination of HR+ tumor cells. Using archival HR+ patient samples, we determined that enhanced collagen levels in tumor-adjacent mammary tissue positively correlated with mast cell abundance and HR+ breast cancer recurrence. Together, these data demonstrate that mast cells programmed by commensal dysbiosis activate mammary tissue fibroblasts and orchestrate early dissemination of HR+ breast tumors.

Supplementary Figure from Reciprocal Interactions Between the Gut Microbiome and Mammary Tissue Mast Cells Promote Metastatic Dissemination of HR+ Breast Tumors