Inflammatory Breast Cancer Patients Research Articles

Abstract PO1-25-04: PTN-positive luminal progenitors induce angiogenesis and metastasis in inflammatory breast cancer

Abstract Background Inflammatory breast cancer (IBC) is a lethal subtype of breast cancer characterized by rapidly arising diffuse erythema and edema of the overlying skin that was thought to contribute to rapid metastasis. Dissecting the intricate cellular ecosystems within tumors and affected skin and their complex interplay may be pivotal in unraveling the aggressive nature of IBC. Methods Integrative analysis containing single-cell RNA sequencing, bulk RNA sequencing, and whole exome sequencing, was performed on paired tumor and skin samples from 17 treatment-naive IBC patients and 5 non-IBC patients from multiple centers. Meanwhile, paraffin sections and serum specimens from two centers were conducted to validate the omics results. Additionally, public single-cell transcriptomic data of non-IBC tumors and normal mammary glands, RNA microarray data from IBC cases, and the Cancer Genome Atlas (TCGA) database were utilized to validate the characteristics of IBC microenvironment. The regulatory mechanism was verified by in vitro experiments. Results We delineated the landscapes of IBC tumor and affected skin microenvironment at the single-cell level and demonstrated that the luminal progenitors (LP) cells highly expressing pleiotrophin (PTN) were most significantly enriched in IBC tumors compared to non-IBC tumors and normal mammary glands, in two independent cohorts. Moreover, the serum concentrations of PTN were significantly higher in IBC patients compared with non-IBC patients. Notably, PTN secreted by PTN+ LP cells interacted with Neuropilin 1(NRP1) receptor on endothelial tip cells in both tumor and affected skin of IBC. Moreover, in vitro assay demonstrated knocking down the expression of NRP1 on human umbilical vein endothelial cells significantly blocked PTN-induced migration, tube formation and sprouting, which might be independent of VEGFA. In addition, two immature phenotypes of PVL_MMP9 and PVL_CCL19 cells recruited by endothelial tip cells via PDGFB/PDGFRB axis were accumulated in affected skin of IBC, which might be associated with promotion of malignant cell metastasis. Finally, we revealed that malignant cells in affected skin of IBC had a higher ability of epithelial-mesenchymal transition than IBC intratumoral malignant cells and identified enhanced crosstalk between immature PVL cells and malignant cells in the skin affected with IBC , through TNFSF12-TNFRSF12A, TGFB-TGFBR1/TGFBR2, MDK-SDC1/4/NCL/(ITGA6+ITGB1). Conclusion We identified a unique, non-malignant epithelial cell subpopulation PTN+ LP cells, which induce massive angiogenesis via the PTN-NRP1 axis, recruit the immature phenotype PVL cells accumulated in affected skin of IBC thus promoting tumor progression. Our findings offer comprehensive insights into the pathogenesis of IBC and uncover a previously unknown, promising therapeutic target. Patient of discovery cohort details Clinical and pathology details for inflammatory breast cancer(IBC) and non-IBC patients analysed by single-cell RNA sequencing(scRNA-seq), bulk RNA sequencing(bulk RNA-seq) and whole exome sequencing(WES) in this study. Clinicalpathological feature of validation cohort Citation Format: Mengmeng Zhang, Kaiwen Zhou, Ting Liu, Filipa Lynce, Filipa Lynce, Wendy Chen, Qianjun Chen, Xiaoping Li, Zhongyu Yuan, Juan Xu, Zhenhai Cai, Jianping Guo, Nan Shao, Ying Lin. PTN-positive luminal progenitors induce angiogenesis and metastasis in inflammatory breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-25-04.

Abstract PO5-27-02: A Tumor Emboli Platform for Morphometric Analysis, Drug screening and for Intravital Optical Imaging in a Murine Model to Simulate Clinicopathological Features of Inflammatory Breast Cancer

Abstract Background: Inflammatory breast cancer (IBC) is distinguished by the presence of tumor emboli, clusters of tumor cells, found within breast parenchyma and dermal lymphatic vessels. These emboli serve as a crucial clinicopathological hallmark, believed to underlie the characteristic diffuse growth pattern and aggressive progression observed in IBC patients, with nearly 30% of patients presenting with metastatic disease at diagnosis. However, the rarity of this cancer and the absence of a solid tumor mass pose challenges in obtaining biospecimens, particularly those with evidence of tumor emboli. To address this pressing need for preclinical models that replicate this distinctive tumor growth pattern, we describe a tumor emboli culture platform that facilitates live imaging, enables compound screening by assessing various phenotypes of the emboli, and permits evaluation of emboli in an in vivo murine model. Methods: The tumor emboli culture system was evaluated for physiological measurements corresponding to dermal lymphatic vessels and subsequently employed to generate tumor emboli from diverse patient-derived cell lines and PDX. Confocal microscopy was employed to characterize cellular information across multiple slices of the tumor emboli. This provided a comprehensive, multi-parametric analysis of single-cell and spheroid phenotypes, including measurements of number, size, shape, and viability of the organoids. Furthermore, we developed imaging algorithms to evaluate phenotypic changes in tumor emboli in response to anti-cancer drug treatment. We also optimized a technique that allows for in vivo tumor emboli implantation including in a transgenic mice with red fluorescent lymphatic vasculature that were surgically implanted with a dorsal skin window chamber. This allowed for intravital optical imaging of the local tumor microenvironment and adjacent skin. Results: Our culture platform enables live imaging of the tumor emboli generated over a span of 7-10 days, maintaining key parameters including kinematic and dynamic viscosity, density along with sheer wall stress within the reported physiological range for lymphatics. Through higher resolution confocal image acquisition and multi-parametric analysis, we conducted particle counting and classification, providing statistically significant insights into the integrity of tumor emboli over time. Additionally, the developed algorithms allowed for quantitative analysis of images from tumor emboli cultures subjected to anti-cancer drugs, revealing disparities in drug efficacy on tumor emboli integrity and dispersion including inter-cluster space within the emboli. Intravital optical imaging, coupled with quantitative analysis of dispersion characteristics of the tumor emboli implanted in the murine model over 5-6 days, demonstrated a diffuse spread reminiscent of observations in IBC patients. Furthermore, immunohistochemistry staining showed marked Ki67, CD45, F4-80 revealing a proliferative tumor microenvironment with high levels of macrophage infiltration. Conclusions: As of now specific targeted therapies for IBC patients remain elusive. Our culture platform for tumor emboli, when combined with advanced imaging techniques both in vitro and in vivo and traditional approaches like immunohistochemistry and genomic evaluation, forms a powerful toolkit for assessing the phenotype and dispersion characteristics of this unique pathological feature in IBC. This preclinical model offers crucial insights, potentially paving the way for precision medicine strategies in the treatment of this understudied cancer. Funding in part from American Cancer Society Mission Boost MBG-20-141-01-MBG grant (GRD), Department of Defense W81XWH-20-1-0153 (GRD), Duke Consortium for Inflammatory Breast Cancer Education (AB, CW, RE). Citation Format: Dorababu Sannareddy, Theresa Charity, Alexandra Bennion, Caroline Way, Edwin Yu, Ralph Erdmann, Gregory M Palmer, Gayathri R Devi. A Tumor Emboli Platform for Morphometric Analysis, Drug screening and for Intravital Optical Imaging in a Murine Model to Simulate Clinicopathological Features of Inflammatory Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-27-02.

Abstract PO2-24-03: Soluble E-cadherin promotes inflammatory breast cancer tumorigenesis via PDIA4-mediated suppression of ferroptosis

Abstract Background: Inflammatory breast cancer (IBC) is an aggressive form of breast cancer known for its rapid progression and high metastatic potential without known distinctive drivers. Currently, there are no FDA-approved targeted therapies specifically for IBC patients, highlighting the urgent need for novel and effective treatments. Through our investigation of metastatic xenograft IBC sublines, we have identified soluble E-cadherin (sEcad), an extracellular proteolytic fragment of full-length E-cadherin, as a protein associated with IBC tumor progression. We hypothesize that sEcad promotes IBC tumorigenesis by suppressing ferroptosis. Methods: MDA-IBC3 (ER–/HER2+) and SUM149 (ER–/HER2–) IBC cell lines were used in this study. Stable overexpression of sEcad in IBC cell lines was achieved using lentiviral vectors. Cell death for ferroptosis was measured by propidium iodide staining using flow cytometry. Mass spectrometry and Bio-ID-based proteomics assays were used to identify sEcad-interacting proteins and potential mechanisms. For in vivo studies, control and sEcad -overexpressing SUM149 and MDA-IBC3 cells were injected into the cleared mammary fat pads of SCID/Beige mice and tumor growth was monitored via caliper measurements. Serum sEcad levels from IBC patients (n=301) were analyzed by ELISA. Results: High serum sEcad levels in IBC patients correlated with poorer OS (p=0.02) and earlier development of metastasis (p=0.006). Overexpression of sEcad in IBC cell lines enhanced cell proliferation and colony formation in vitro. Mice injected with sEcad-overexpressing SUM149 and MDA-IBC3 cells had significantly higher tumor growth rates compared to controls (SUM149: p=0.007; MDA-IBC3: p=0.006). Mechanistically, mass spectrometry and Bio-ID assays identified Protein Disulfide Isomerase Family A Member 4 (PDIA4) as a novel binding partner of sEcad, which was validated through co-immunoprecipitation. Additionally, sEcad increased the expression of PDIA4, an enzyme that plays a role in cellular redox regulation and protein folding. PDIA4 has been shown to regulate key players of ferroptosis such as ATF4, SLC7A11. Our results showed that, compared to controls, sEcad-overexpressing IBC cells displayed significant resistance to ferroptosis inducers, including RSL3, FIN56, and sulfasalazine. Knockdown of PDIA4 in sEcad high-expressing cells significantly increased their sensitivity to ferroptosis-promoting drugs. Moreover, we found that PDIA4 regulates ATF4 to impact ferroptosis-mediated cell death in IBC cells. Conclusions: Our study shows that sEcad affects ferroptosis through PDIA4, impacting tumorigenesis in IBC. These findings uncover a novel and pivotal role for sEcad in IBC tumor growth and progression, providing new insights and potential therapeutic targets for IBC patients. Citation Format: Xiaoding Hu, Yun Xiong, Emilly Villodre, Juhee Song, Debu Tripathy, Wendy Woodward, Savitri Krishnamurthy, Junjie Chen, Bisrat Debeb. Soluble E-cadherin promotes inflammatory breast cancer tumorigenesis via PDIA4-mediated suppression of ferroptosis [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-24-03.

Abstract PO2-09-05: Building genomic and transcriptomic data among African American and Black patients with triple-negative inflammatory breast cancer

Abstract Background: Inflammatory breast cancer (IBC) is an aggressive breast cancer associated with poor response and early metastases. It represents a health disparity, with higher incidence and worse outcomes in Black compared to White patients. Further, IBC is enriched for the more aggressive triple-negative receptor subtype, TN-IBC, and this subtype is more prevalent among Black IBC patients. It is critical to identify genetic and molecular features that may guide better treatments for these aggressive cancers across races, and thus imperative to identify and increase racial representation among bioinformatics datasets. We previously performed comprehensive genomic and transcriptomic analyses for TN-IBC patient samples and here examine the differences among self-identified African American or Black (AA/B) and other races among IBC patients. Methods: As previously described, we collected matched blood and baseline tumor samples before treatment from 19 patients with primary TN-IBC. We performed whole exome and RNA sequencing (RNA-Seq) on these samples and compared mutations and differentially expressed genes (DEGs). Results were compared between 3 AA/B patient tissues vs the remaining 16 (Other) cases. Results: Mutations shared by all AA/B patients included amplification of the five most commonly mutated hallmark genes in the complete cohort, ARNT, BCL9, DDR2, FCGR2B and LMNA (all 100% in AA/B patients versus all 50% in the Other cohort). All AA/B patients had a Notch1 mutation (two deletions and one missense mutation, 100% AA/B vs 6% Other (one deletion)). Comparing differentially expressed genes and gene set enrichment analyses of the Broad molecular signatures database (MSigDB) demonstrates the majority of DEGs are downregulated in these AA/B patients. Six of the top 20 downregulated gene sets from the MSigDB C2 group relate to breast cancer subtype and among this TNIBC cohort AA/B tumor expression was downregulated for luminal and normal subtype related genes in multiple gene sets and enriched in the Lien metaplastic related genes. In the MSigDB C5 sets, over half of the top 20 enriched gene ontology sets among AA/B patients related to chromosomes, chromatin, spindle assembly or histone binding, while 16 of the top 20 downregulated enriched sets related to immune function. Multiple KEGG pathways enriched in AA/B cases related to RNA processing and expression and DNA replication and repair. Lastly, hallmark gene sets enriched in AA/B patients were cell cycle related, and targets of Myc, Hedgehog, B-catenin, TGFb, and TNFa via NFKb, while top significantly downregulated sets related to metabolism and immune response. Conclusion: While findings from a small sample size can only be considered hypothesis generating, some patterns emerge from the data among this rare cohort of AA/B TN IBC patients. These tumors appear to be devoid of luminal signals, characterized by cell cycle and chromatin remodeling signals, enriched for signaling typical of stem cell self-renewal, and perhaps more immune-deprived than other TN-IBC. Additional work to build racially diverse IBC transcriptomic data are needed to develop strategies to understand and improve outcomes for these patients. Citation Format: Wencai Ma, Li Zhao, Gayathri Devi, Savitri Krishnamurthy, Larry Coffer, Angela Alexander, Megumi Kai, Xiaoping Wang, Huong Le-Petross, Miral Patel, Bisrat Debeb, Chandra Bartholomeusz, Jianhua Zhang, Xingzhi Song, Andrew Futreal, Naoto Ueno, Rachel Layman, Anthony Lucci, Jing Wang, Wendy Woodward. Building genomic and transcriptomic data among African American and Black patients with triple-negative inflammatory breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-09-05.

Abstract PO2-24-06: Cancer-Associated Fibroblasts Promote Tumor Stemness in Aggressive Breast Cancers via NDRG1

Abstract Background: Inflammatory breast cancer (IBC) and triple negative breast cancer (TNBC) have the lowest 5-year survival rates among breast cancers: 40% for IBC and 77% for TNBC. Effective treatments for these aggressive tumors are urgently needed. To develop better treatments, it is crucial to understand the underlying mechanisms driving their aggressive biology. Our recent research has identified N-myc downstream regulated gene 1 (NDRG1) as a crucial driver of tumor progression and metastasis in aggressive breast cancers. We have also found that NDRG1 expression in tumors is correlated with poorer outcomes in IBC patients. Additionally, we have observed that cancer-associated fibroblasts (CAFs), derived from breast cancer biopsies, stimulate NDRG1 expression and phosphorylation as well as tumor stemness. Based on these findings, we hypothesize that NDRG1 is a key regulator of tumor stemness and progression, and secreted stromal factors regulate tumor stemness through NDRG1. Methods: To assess tumor stemness, we conducted in vitro experiments by quantifying the CD44+/CD24- subpopulation and performing mammosphere assays in NDRG1 control and depleted cells (SUM149, BCX010, MDA-IBC3). In vivo, we employed a limiting dilution transplantation assay, where NDRG1 control and knockdown SUM149 cells were transplanted into the mammary fat pad at different dilutions. We treated NDRG1 control and knockdown breast cancer cells with different patient-derived CAF-conditioned media (CAFs-CM, 50%, 24h) or control medium. The expression of NDRG1/pNDRG1 and CD44+/CD24- cells was evaluated by immunoblotting and flow cytometry. qPCR array was performed to evaluate tumor stemness markers. Results: NDRG1 depletion significantly reduced the CD44+/CD24- subpopulation (p< 0.001) and the efficiency of mammosphere formation (p=0.001). In vivo limiting dilution experiments demonstrated a substantial reduction in the frequency of breast cancer stem cells in NDRG1 knockdown cells (p= 1 x 10-12). Treatment of IBC cells with CAF-CM derived from breast cancer patients stimulated the cancer stem cell subpopulation [CD44+/CD24-: Control medium (43.1 ± 0.1) vs CAF-CM (55.1 ± 0.7); p=0.004] and increased NDRG1 and phospho-NDRG1 expression. However, the stimulation of NDRG1 knockdown cells with CAF-CM did not significantly alter the cancer stem cell population (0.2 ± 0.2 in Control medium versus 0.4 ± 0.3 in CAF-CM) and the expression of NDRG1/phospho-NDRG1. Additionally, qPCR array analysis revealed the upregulation of several cancer stem cell and self-renewal markers in CAF-CM stimulated cells compared to control-medium treated cells. Conclusions: Our data strongly support the role of NDRG1 as a critical regulator of tumor stemness. Moreover, we have discovered that conditioned media from patient-derived CAFs induces tumor stemness in breast cancer cells, and this effect is dependent on the expression NDRG1. Citation Format: Emilly Villodre, Jenny M Hogstrom, Xiaoding Hu, Nina Kozlova, Debu Tripathy, Taru Muranen, Bisrat Debeb. Cancer-Associated Fibroblasts Promote Tumor Stemness in Aggressive Breast Cancers via NDRG1 [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-24-06.

Abstract PO5-10-04: Rare to Care: Assessing Awareness and Health Disparity Factors Related to Inflammatory Breast Cancer in the Primary Care Setting

Abstract Background: The diagnosis of inflammatory breast cancer (IBC) is life-changing as it is a rare, highly aggressive breast cancer variant designated by NIH as a cancer health disparity. Given the unique presentation of diffuse tumor cell spread in the absence of a solid mass, which is not easily detected by self-breast exams or mammograms, IBC patients often face delays in diagnosis and treatment. Therefore, an individualized and a multifaceted approach that addresses the unique needs of the patient with input from both providers and the community is an unmet need. To address this, we are investigating the current knowledge and perspectives of providers and public related to rare cancers like IBC in primary care practices. Methods: Researchers and advanced practice providers collaboratively drafted and piloted the initial surveys with guidance from a Community Advisory Board, comprising of members from academic institutions, primary care practices in urban and rural setting, topical experts, and patient advocates, in order to assess primary care providers (PCPs) and general public knowledge, attitudes and health seeking practices related to rare cancer like IBC. Results: The surveys are currently being administered statewide specific to PCPs or public via cognitive interviews and/or using an online survey tool within North Carolina as a model of a large state (100 counties) with a range of population densities, race, ethnicities, and environmental burdens. Challenges elaborated at the PCP level include communicating rare cancer information, gaps in confidence in diagnosing IBC, timely follow-up with patients, and accessing specialty care and an unmet need for developing PCP educational modules to improve guideline-concordant care. Public data analyzed to date is from a Duke Outpatient Clinic, an urban ambulatory care teaching practice serving primarily low-income, medically complex patients in Durham (n=14) included 69% Black, 93% female, with 68% in households earning under $50,000 annually). 71% had not heard of IBC; 64% did not identify high BMI as a risk factor; 36% did not know there is differential race-related incidence; 74% did not recognize IBC-specific symptoms. 50% noted lack of insurance, transportation, religious reasons, or difficulty or fear of talking to a physician contributed in general delay in seeking health care. Most importantly, 93% expressed feeling comfortable sharing information about IBC with others. Majority expressed that adding visual aids and providing educational materials about IBC at the time of survey would be helpful. Conclusions: The results highlight the role of PCPs, including physicians, physician assistants, and nurse practitioners, who are often the first point of contact when patients begin to notice signs or symptoms. The general public and the patients with common breast cancer subtypes can provide valuable insight into their own health care experiences, what works for them and what barriers they face in their communities, which can be used to compare with experience of patients with IBC and other rare cancers. Overall, the lessons from this study inform the development of effective tools to educate PCPs and patients for this understudied cancer that contributes to disparities in clinical and survival outcomes in minoritized and marginalized populations. Support in part from the Duke Cancer Institute pilot as part of the P30 Cancer Center Support Grant (P30CA014236) and Duke School of Medicine Behavioral Health and Survey Research Core Facility Award (GRD, ANT); Duke Advanced Practice Provider Leadership Institute scholarship (VK, GRD), Department of Surgery (GRD); Duke Ahead Education grant; NIH/NCI RO1CA264529-01 (GRD); ACS Mission Boost grant MBG-20-141-01-MBG (GRD), Nakayama Public Service Scholar Award (AB). Citation Format: Gayathri R Devi, Lawrence Greenblatt, Rashmi Saincher, Valerie Keck, Beau Blass, Sarah Weaver, Alexandra Bennion, Anh Tran. Rare to Care: Assessing Awareness and Health Disparity Factors Related to Inflammatory Breast Cancer in the Primary Care Setting [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-10-04.

Abstract PO5-16-05: Integrating Circulating Tumor Cells (CTCs) and Cell-free DNA (cfDNA) Signatures for Monitoring Treatment Response in Stage III/IV Inflammatory Breast Cancer

Abstract Background: Inflammatory breast cancer (IBC) is a rare and aggressive form of breast cancer, comprising only between 1-5% of all breast cancer cases in the United States. Despite its low incidence, IBC accounts for 10% of breast cancer-related deaths and is often diagnosed with metastasis, resulting in shorter survival compared to non-IBC cases. The 5-year relative survival rate for all stages of IBC is 39%, dropping to 19% for patients with distant metastasis. Liquid biopsy-based biomarkers have emerged as potential analytes for predicting prognosis and monitoring response to therapies in IBC patients. We explored the prognostic role of liquid biopsy encompassing both CTCs and cfDNA in the blood of patients with stage III/IV IBC and their clinical outcomes. Methods: CTC and cfDNA analysis was performed on 90 blood samples from 47 patients with stage III and IV IBC. Samples were collected before (pre-treatment, n=43) initiation and after (post-treatment, n=47) completion of neoadjuvant chemotherapy. CTCs were enriched and enumerated using the CellSearch® platform (Menarini-Silicon Biosystems). CfDNA was extracted from plasma using MagMax™ Cell-Free Total Nucleic Acid Isolation Kit (Applied Biosystems™) and quantified using the Qubit™ dsDNA High Sensitivity kit (Invitrogen™). Differences in cfDNA concentrations were used to plot a receiver operating characteristic (ROC) curve which was then used to determine Area Under the Curve (AUC) and a cfDNA cut-off point. ROC cut-off was calculated based on Youden Index J. Survival analysis was performed by the Kaplan-Meier estimator and Cox regression models. P-values were measured using the Student t-test. Results: Prior to neoadjuvant treatment, CTC was detected in 51% of patient samples, and the median cfDNA concentration was 5.87 ng/mL (range 0.95-24.11 ng/mL). After completion of neoadjuvant treatment, CTC was detected in 25% of patient samples, and the median cfDNA concentration was 11.19 ng/mL (range 3.41-88.13 ng/mL). The cut-off points determined for pre-treatment and post-treatment cfDNA concentration was >4.2 ng/mL and >9.5 ng/mL respectively. At pre-treatment, CTC detection and cfDNA concentration >4.2 ng/mL were independently associated with disease relapse (P=0.007, 0.016, respectively). The combination of CTC detection and cfDNA concentration >4.2 ng/mL was significantly associated with disease relapse (P=0.0004), decreased relapse free survival (RFS, P=0.005) and overall survival (OS, P=0.007). At the post-neoadjuvant treatment time point, the combination of CTC detection and cfDNA concentration >9.5 ng/mL was significantly associated with relapse regardless of pCR status (P=0.02). Conclusion: The combined presence of CTCs and elevated cfDNA concentrations in patients with stage III/IV IBC after completion of neoadjuvant chemotherapy was associated with disease relapse regardless of pCR status. A combination of elevated cfDNA and CTC detection signatures after completion of neoadjuvant chemotherapy may be useful for risk stratification and adjuvant systemic therapy planning. Citation Format: Sridevi Addanki, Salyna Meas, Vanessa Sarli, Abdulkader Almosa, Wendy Woodward, Dhruvajyoti Roy, Anthony Lucci. Integrating Circulating Tumor Cells (CTCs) and Cell-free DNA (cfDNA) Signatures for Monitoring Treatment Response in Stage III/IV Inflammatory Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-16-05.

Abstract PO5-01-03: Neoadjuvant HER2-targeted regimens with or without anthracyclines for HER2-positive inflammatory breast cancer (IBC): a multicenter retrospective study

Abstract Background Previous randomized clinical trials have shown no significant benefit with the addition of anthracyclines to neoadjuvant treatment for HER2-positive breast cancer. However, these studies did not focus on inflammatory breast cancer (IBC), or a small minority of patients on these trials. The study aims to compare pathologic complete response rates with and without anthracyclines in HER2-positive IBC. Methods We reviewed patients diagnosed with Stage III HER2-positive IBC who underwent neoadjuvant therapy and modified radical mastectomy at MD Anderson Cancer Center and Dana-Farber Cancer Institute between 2014 and 2021. Patients received either docetaxel/trastuzumab/pertuzumab-doxorubicin/cyclophosphamide (THP-AC) or docetaxel/carboplatin/trastuzumab/pertuzumab (TCHP). The primary outcome was pathologic complete response (pCR) rate, defined as ypTisT0/N0. Secondary outcomes included 2-year event-free survival (EFS) and overall survival (OS). Univariate and multivariable analyses were performed with adjustments for clinically relevant covariates. Results Ninety-nine patients were included in the analysis. Thirty-nine patients received TCHP and 60 received THP-AC. The median follow-up time was 3.02 years. Three patients had disease progression during neoadjuvant therapy. pCR rates did not differ between the two regimens (48.7% TCHP vs. 51.7% THP-AC; p = 0.774). Patient’s baseline characteristics did not significantly affect the pCR rate, except for age. A multivariable logistic regression model adjusted for age and estrogen receptor (ER) status did not show a significant association between pCR and regimen (odds ratio 1.232, 95% CI 0.537–2.829 for THP-AC vs. TCHP, p = 0.623). The 2-year EFS rates for TCHP and THP-AC were 57% and 74%, respectively. In univariate analysis, patients who received THP-AC had better EFS than patients who received TCHP (hazard ratio [HR] 0.423, 95% CI 0.214–0.835, p = 0.013). The EFS benefit of THP-AC remained statistically significant after adjusting for age and type of adjuvant therapy in the final reduced multivariable Cox model (HR 0.441, 95% CI 0.220–0.882, p = 0.021). Univariate analysis did not show a significant association between EFS and other baseline covariates (body mass index, race, N and M category, nuclear grade, ER status, and HER2-targeted therapy). OS did not differ between the THP-AC and TCHP groups (HR 0.419, 95% CI 0.122–1.440, p = 0.167). Conclusions The present analysis revealed that a non–anthracycline-containing regimen in HER2-positive IBC patients had no significant difference in pCR rates but was associated with lower 2-year EFS when compared to an anthracycline-containing regimen. However, OS was similar. Limitations of the study include a small sample size, lack of temporal analysis, and retrospective design with its possible selection bias. Further investigation of the optimal neoadjuvant regimen for patients with HER2-positive IBC is warranted. Citation Format: Toshiaki Iwase, Sridhar Nithya, Megumi Kai, Jie Willey, Wenli Dong, Yu Shen, Savitri Krishnamurthy, Anthony Lucci, H. T. Carisa Le-Petross, Azadeh Nasrazadani, Sadia Saleem, Rachel Layman, Vicente Valero, Debu Tripathy, Wendy Woodward, Yee Chung Cheng, Faina Nakhlis, Jennifer Bellon, Filipa Lynce, Naoto Ueno. Neoadjuvant HER2-targeted regimens with or without anthracyclines for HER2-positive inflammatory breast cancer (IBC): a multicenter retrospective study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-01-03.

Abstract PO2-14-10: A selective MCL-1 inhibitor AZD5991 showed tumor regression in a triple-negative inflammatory breast cancer xenograft model

Abstract Background Triple-negative breast cancer (TNBC) accounts for 15-20% of all breast cancer diagnoses but up to 30% of breast cancer-related deaths. Similarly, Inflammatory breast cancer (IBC) accounts for 2-4% of breast cancer diagnosis but causes 8%–10% of all breast cancer-related deaths. The myeloid cell leukemia-1 (MCL-1) is a member of the BCL-2 family of proteins, which is highly amplified in numerous human cancers and associated with cell immortalization, transformation, and chemoresistance. In fact, MCL-1 is amplified in 55% of TNBC after preoperative chemotherapy. Amongst the MCL-1 inhibitors that have been developed, AZD5991 showed high selectivity and affinity for MCL-1. In myeloma and acute myeloid leukemia cells AZD5991 induces apoptosis and showed anti-tumor effects in in vivo models. In the present study, we evaluated the biological role of the MCL-1 inhibitor AZD5991 in IBC and TNBC in vitro and in vivo models. Materials and methods The expression of the MCL-1 gene was analyzed in the World Consortium IBC patient dataset. Next, we screened a panel of TNBC and IBC cell lines for MCL-1 expression by western blot analysis. The effect of AZD5991 on TNBC and IBC cells was analyzed via cell titer-blue proliferation, clonogenic assays and soft agar assay. To further validate these findings, we used siRNA to knockdown MCL-1 and performed cell proliferation, clonogenic and migration assays. To identify signaling pathways involved in MCL-1 Inhibitor’s effects we performed a proteome profiler human apoptosis array in TNBC cells in the presence of AZD5991. The anti-tumor effect of the MCL-1 inhibitor was evaluated using a SUM-149 (TN-IBC) orthotopic xenograft mouse model. The mice were treated with AZD5991 at doses of 15 and 30mg/kg once weekly via tail vein injection for a duration of 4 weeks. Results The mean expression level of MCL-1 was higher in patients with TNBC than in those with non-TNBC. Further, compared to the patients with ER positive, HER-2 negative tumors those with TNBC showed an increased in the mean expression of MCL-1 gene (p value= 0.05). We screened a panel of TNBC and IBC cell lines in which most of the cell lines showed high levels of MCL-1. The cell proliferation assay showed IC50 ranging from 0.27 – 19.6 μM. The SUM149, SUM190, FCIBC02, MDA-IBC3 and MDA-MB-468 cells showed high sensitivity and showed significant decrease in the proliferation rate while BCX010, KPL4, MDA-MB-231, 4T1.2 and E0771 cells as well as the normal breast cells MCF10A exhibited resistance with no significant decrease in proliferation. The clonogenic and soft agar assays with these sensitive and resistant cell lines showed similar results. Further, these findings were validated via genetic knockdown of MCL-1 which resulted in a significant decrease in cell proliferation, colony formation and migration capability of the TNBC cells. To identify signaling pathways involved in MCL-1 Inhibitor’s phenotypic changes, we performed a proteome profiler human apoptosis array which showed a decreased in BCLx expression, and an increase in expression of BAX and phospho-Rad17 proteins in the AZD5991 treated TN-IBC cells. Finally, in a SUM-149 (TN-IBC) orthotopic xenograft mouse model, mice injected with 30mg/kg showed a significant tumor regression compared to the vehicle-treated mice (vehicle vs 30 mg/kg, p value=0.0006). Conclusions and Future directions Our data demonstrates that AZD5991 inhibits tumorigenesis in an inflammatory breast cancer xenograft model. We are currently validating several significant targets to understand the biological mechanisms related to our candidate drug. Our long-term goal is to develop MCL-1 targeted therapy in combination with standard-of-care treatment for inflammatory and triple-negative breast cancers. Citation Format: Mohd Mughees, Moises Tacam, Alex Tan, Michael White, Bisrat Debeb, Emilly Villodre, Xiaoding Hu, Debu Tripathy, Wendy Woodward, Rachel Layman, Geoffrey Bartholomeusz, Chandra Bartholomeusz. A selective MCL-1 inhibitor AZD5991 showed tumor regression in a triple-negative inflammatory breast cancer xenograft model [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-14-10.

Abstract PO3-02-07: HER2-low status in inflammatory breast cancer (IBC) is associated with hormone receptors positivity but not with pathological response to neoadjuvant chemotherapy or overall survival

Abstract Background: Half of HER2-negative breast cancers (BC) show HER2-low expression. The strong efficacy of recent anti-HER2 antibody-drug conjugates (ADC) in HER2-low tumors has risen the interest of HER2-low as a proper BC subtype. However, HER2-low non-inflammatory breast cancer (non-IBC) appears to have only marginal clinicopathological differences compared to HER2-0. Little is known about HER2-low clinical significance in IBC. Methods: Data from patients diagnosed with HER2-negative IBC between 1990 and 2021 were collected from the Institut Paoli-Calmettes European Comprehensive Cancer Center database. Two tumor groups were defined (HER2-low and HER2-0). HER2-low tumors were defined by HER2 IHC score of 1+ or 2+ with negative FISH, and HER2-0 by IHC score of 0+. Hormone Receptor (HR) status was determined according to the French guidelines (oestrogen and/or progesterone receptors by IHC with a 10% threshold for HR-positivity). Clinicopathological characteristics, pCR (defined as [ypT0/ypTis] and [pN0sn or ypN0]), and OS rates were compared between the two tumor groups. Results: The individual data of 256 IBC patients were analyzed. Thirty-seven percent of tumors were HER2-low and 63% were HER2-0. Among patients with stage III (n = 226) and stage IV (n = 30) IBC, 35% and 53% had HER2-low tumors, respectively. HR positivity, age over 50 years, SBR grade, and menopausal status were associated with HER2-low in univariate analysis, but only HR positivity remained significant in a binary logistic regression (OR: 1.95 [1.06-3.58]; p=3.15E-02). In stage III patients, the pCR rate after neoadjuvant chemotherapy was similar in HER2-low (24%) and HER2-0 (29%) patients (p=0.550). No difference was observed by analyzing pCR by HR status. In univariate analysis, overall survival was affected by the clinical axillary lymph node invasion the presence of metastasis, the pathological type and menopausal status, but not by HER2 status. Conclusion: In IBC, HER2-low is associated with HR positivity but has no effect on pathological response to chemotherapy and overall survival in our retrospective cohort, consistently with data available in non-IBC patients. Of 256 IBC patients, 37% were HER2-low. These results may be useful to design future clinical trials testing anti-HER2 ADCs in IBC. Citation Format: Alexandre de Nonneville, Pascal FINETTI, Laurys Boudin, Lucas Usclade, Patrice Viens, Frederic VIRET, Emilie Mamessier, Anthony Gonçalves, François BERTUCCI. HER2-low status in inflammatory breast cancer (IBC) is associated with hormone receptors positivity but not with pathological response to neoadjuvant chemotherapy or overall survival [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-02-07.

Abstract PO5-09-10: Inflammatory Breast Cancer Patient Profile in a Population of Puerto Rican Women

Abstract Background: Breast cancer (BC) is the most frequently diagnosed cancer type, as well as the leading cause of cancer death among women in Puerto Rico (PR). Moreover, inflammatory breast cancer (IBC) is a highly aggressive BC subtype. The current study aimed to describe the patient profile and the clinicopathological characteristics of IBC tumors in Hispanic women living in Puerto Rico. Methods: This is a retrospective, population-based study using the Puerto Rico Central Cancer Registry (PRCCR) database and the Health Insurance Linkage Database (PRCCR-HILD) to identify and describe the patient profile of Puerto Rican women diagnosed with IBC from 2008 to 2018. Variables such as age at diagnosis, staging variables, tumor receptor subtypes, treatment received, and overall survival (OS) were studied. Statistical analysis methods were employed to describe the population, estimate survival curves and examine the risk of dying. Results: We identified a total of 51 patients. The mean age at diagnosis of IBC in the current study was 59 years old, which is older than the mean age at diagnosis of IBC for women in the mainland US, but younger than the mean age of women that are diagnosed with BC in PR (63 years old). A total of 62.8% of patients had no metastases at diagnosis and 64.7% were diagnosed with stage III disease. Most tumors presented with ER+/PR+/Her2- (21.6%), or a triple-negative (ER-/PR-/Her2-, 15.7%) tumor concordance. The OS during the 12 months post-diagnosis was 66%, whereas at 36 months, OS decreased to 39%. The triple-negative subtype had the worst survival at 36 months (36%). Women with stage IV disease and those with ER-/PR- tumor subtype had a higher risk of dying. Conclusions: This is the first research to describe the patient profile and characteristics of women diagnosed with IBC in Puerto Rico. Our results suggest that the Puerto Rican IBC patient population presents unique characteristics. This research increases awareness about this lethal disease in PR. Citation Format: Luz Arroyo-Cruz, Michelle Martinez-Montemayor. Inflammatory Breast Cancer Patient Profile in a Population of Puerto Rican Women [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-09-10.

Abstract 6203: An altered profile of ribosomal proteins and ERK-eIF4E translational control in an inflammatory breast cancer model of acquired resistance and reversal is associated with pathological complete response in patients

Abstract Background: Drug resistance is a major challenge in inflammatory breast cancer (IBC), a hyperproliferative subtype characterized by the presence of diffuse tumor cell clusters that show high level of heterogeneity. As the degree of tumor heterogeneity during cancer progression can cause evolution of cell states that can either compete or co-operate resulting in therapeutic failure, the study objective was to identify drug resistance networks that can serve as biomarkers or therapeutic targets. Methods: Integrated transcriptomic and proteomic profiling approach was conducted in a progression model of acquired drug resistance and its reversal comprised of a treatment-naïve patient-derived SUM149 cell line, along with two isogenic derivatives and representing drug-resistant (rSUM149) and resistance-reversal states (rrSUM149). Global gene expression analysis in IBC patients (n=87) recorded responses to neoadjuvant chemotherapy. Based on the data, targeted multikinase inhibitors were evaluated in viability and signaling assays. Results: We identified specific ribosomal proteins associated with resistance acquisition, which correlated with high levels of pERK, CDK1, XIAP, and SOD2. Conversely, the resistance reversal in rrSUM149 showed almost complete normalization to the profile of SUM149. However, VIPER analysis revealed proteins related to ribosomal processes (AGO2, Exportin 1, RPL5) that did not revert in rrSUM149, suggesting this pathway may have pleiotropic effects in governing drug resistance. Notably, genes linked to ribosomal processes were significantly enriched (P<0.001) among the overexpressed genes in IBC patients (n=87) who exhibited pCR to neoadjuvant chemotherapy. This is crucial as IBC tumors, including rSUM149, exhibit MAPK hyperactivation including in the presence of EGFR tyrosine kinase inhibitors. Treatment with Merestinib, a multikinase inhibitor, suppressed pERK, peIF4E, downstream targets like CDK1, and ribosomal protein IMP3 underscoring the impact on protein synthesis signaling crucial for countering translational dependence in cancer cells. Additionally, Merestinib synergized with EGFR-TKI (lapatinib) in increasing cell death in all three states. Conclusion: Overall, our study describes adaptive changes in response to both therapeutic stress and therapy break that have the potential to serve as biomarkers or extended for pharmacological interrogation toward precision medicine for this rare, understudied cancer. Furthermore, the ability of Merestinib, in clinical trials, to target translational dependence is attractive as cancer cells often appropriate these signaling pathways to gain tolerance to various stress stimuli. Support: NIH-R01CA264529; DoD Breast Cancer Breakthrough level 2 Award W81XWH2010153 Citation Format: Gayathri R. Devi, Pritha PAI, Matthew W. Foster, Dorababu S. Sannareddy, Seayoung Lee, Steven V. Laere. An altered profile of ribosomal proteins and ERK-eIF4E translational control in an inflammatory breast cancer model of acquired resistance and reversal is associated with pathological complete response in patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6203.

A subpopulation of luminal progenitors secretes pleiotrophin to promote angiogenesis and metastasis in inflammatory breast cancer.

Inflammatory breast cancer (IBC) is a highly aggressive subtype of breast cancer characterized by rapidly arising diffuse erythema and edema. Genomic studies have not identified consistent alterations and mechanisms that differentiate IBC from non-IBC tumors, suggesting that the microenvironment could be a potential driver of IBC phenotypes. Here, using single-cell RNA sequencing, multiplex staining, and serum analysis in IBC patients, we identified enrichment of a subgroup of luminal progenitor (LP) cells containing high expression of the neurotropic cytokine pleiotrophin (PTN) in IBC tumors. PTN secreted by the LP cells promoted angiogenesis by directly interacting with the NRP1 receptor on endothelial tip cells located in both IBC tumors and the affected skin. NRP1 activation in tip cells led to recruitment of immature perivascular cells in the affected skin of IBC, which are correlated with increased angiogenesis and IBC metastasis. Together, these findings reveal a role for crosstalk between LPs, endothelial tip cells, and immature perivascular cells via PTN-NRP1 axis in the pathogenesis of IBC, which could lead to improved strategies for treating IBC.

251 (PB-067) Poster - XIAP overexpressing Inflammatory Breast Cancer Patients have high Infiltration of immunosuppressive subsets and increased TNFR1 signaling targetable with Birinapant, a pan- IAP antagonist

251 (PB-067) Poster - XIAP overexpressing Inflammatory Breast Cancer Patients have high Infiltration of immunosuppressive subsets and increased TNFR1 signaling targetable with Birinapant, a pan- IAP antagonist

XIAP overexpressing inflammatory breast cancer patients have high infiltration of immunosuppressive subsets and increased TNFR1 signaling targetable with Birinapant

ObjectiveTo assess the expression pattern of X-linked inhibitor of apoptosis protein (XIAP), a cellular stress sensor, and delineate the associated changes in the tumor immune microenvironment (TiME) for prognostic value and new therapeutic targets in inflammatory breast cancer (IBC). MethodsImmunohistochemistry was conducted to assess the spatial localization of immune subsets, XIAP, and PDL1 expression in IBC and non-inflammatory breast cancer (nIBC) pretreatment tumors (n = 142). Validation and further exploration were performed by gene expression analysis of patient tumors along with signaling studies in a co-culture model. ResultsHigh XIAP in 37/81 IBC patients correlated significantly with high PD-L1, increased infiltration of FOXP3+ Tregs, CD163+ tumor-associated macrophages (TAMs), low CD8/CD163 ratio in both tumor stroma (TS) and invasive margins (IM), and higher CD8+ T cells and CD79α+ B cells in the IM. Gene set enrichment analysis identified cellular stress response- and inflammation-related genes along with tumor necrosis factor receptor 1 (TNFR1) expression in high-XIAP IBC tumors. Induction of TNFR1 and XIAP was observed when patient-derived SUM149 IBC cells were co-cultured with human macrophage-conditioned media simulating TAMs, further demonstrating that the TNF-α signaling pathway is a likely candidate governing TAM-induced XIAP overexpression in IBC cells. Finally, addition of Birinapant, a pan IAP antagonist, induced cell death in the pro-survival cytokine-enriched conditions. ConclusionUsing immunophenotyping and gene expression analysis in patient biospecimens along with in silico modeling and a preclinical model with a pan-IAP antagonist, this study revealed an interplay between increased TAMs, TNF-α signaling, and XIAP activation during (immune) stress in IBC. These data demonstrate the potential of IAP antagonists as immunomodulators for improving IBC therapeutic regimens.

Treatment Response, Tumor Infiltrating Lymphocytes and Clinical Outcomes in Inflammatory Breast Cancer-Treated with Neoadjuvant Systemic Therapy.

IBC is a rare, but very aggressive type of breast cancer. The prognostic role of pCR after systemic therapy and the predictive value of sTILs for pCR are well established in the general breast cancer population; however, only limited information is available in IBC. We assembled the largest retrospective IBC series so far and demonstrated that sTIL is predictive of pCR. We emphasize that reaching pCR remains of utmost importance in IBC.

ER+/PR− phenotype exhibits more aggressive biological features and worse outcome compared with ER+/PR+ phenotype in HER2-negative inflammatory breast cancer

The loss of progesterone receptor (PR) often predicts worse biological behavior and prognosis in estrogen receptor-positive (ER +) breast cancer. However, the impact of PR status on inflammatory breast cancer (IBC) has not been studied. Therefore, the purpose of our study was to investigate the influence of PR on IBC. Patients with ER+ and HER2-negative IBC were selected from the Surveillance, Epidemiology and End Results database. Pearson’s χ2 test was used to compare the clinicopathological characteristics between patients with estrogen receptor-positive/progesterone receptor-positive (ER+/PR +) and patients with estrogen receptor-positive/progesterone receptor-negative (ER+/PR−). Univariate and multivariate analyses were performed to investigate the effects of PR status on the breast cancer-specific survival (BCSS) and overall survival (OS) in IBC. Overall, 1553 patients including 1157 (74.5%) patients with ER+/PR+ and 396 (25.5%) patients with ER+/PR− were analyzed in our study. The patients with ER+/PR− were more likely to be high histological grade (p < 0.001) and liver metastasis (p = 0.045) compared to patients with ER+/PR+. Despite higher chance of receiving chemotherapy (83.6% vs 77.3%, P = 0.008), patients with ER+/PR− showed worse BCSS (5-year BCSS rate, 34.3% vs 51.3%, P < 0.001) and OS (5-year OS rate, 31.3% vs 46.1%, P < 0.001) compared with ER+/PR+ phenotype. Multivariate survival analysis showed that patients with ER+/PR− still had worse BCSS (hazard ratios [HR]: 1.764, 95% confidence intervals [CI] 1.476–2.109, P < 0.001) and OS (HR: 1.675, 95% CI 1.411–1.975, P < 0.001) than ER+/PR+ phenotype. Furthermore, patients with ER+/PR− showed worse outcomes than ER+/PR+ phenotype in most subgroups, especially in patients with younger age (≤ 60 years), lower histological grade, lymph node involved and distant metastasis. Patients with ER+/PR− had more aggressive biological behaviors and worse outcomes than patients with ER+/PR+ in IBC. Stronger treatments maybe needed for IBC patients with ER+/PR−.

Inflammatory breast cancer: As surgical oncologists, what can we do?

Breast cancer surgery is the primary treatment for early-stage breast cancer. However, inflammatory breast cancer (IBC), with its specific presentation characterized by skin invasion, is unfit for primary surgery. According to the different guidelines, the management of IBC is trimodal with the coordination of oncologists, surgeons, and radiation therapists. Advances in breast cancer imaging and the development of more targeted therapies make new challenges for this aggressive cancer. This chapter aims to provide an update on the role of surgery in IBC. Radical surgery is still considered the standard surgical treatment in IBC. Some authors suggest a conservative surgery in patients with a clinical response to chemotherapy without affecting survival. For lymph node surgery, the sentinel lymph node biopsy (SLNB) is not feasible in IBC patients, according to the existing studies. However, prospective studies on SLNB are needed to verify its reliability after chemotherapy for a specific group of patients. In the metastatic IBC, surgery can be considered if there is a good response after chemotherapy or for uncontrolled symptoms. Existing studies showed that surgery may impact survival for these patients. Prospective studies are mandatory to optimize IBC management, considering factors such as tumor's molecular profile.

Inflammatory breast cancer: Epidemiologic data and therapeutic results.

Since the early description more than a century ago, inflammatory breast cancer (IBC) remains an aggressive disease, with a different geographic repartition, with the highest ones incidence reported in the North of Africa (Tunisia, Algeria, Morocco, and Egypt), and the lowest incidence in Western countries (USA, Europe…). In this study, we reviewed the literature using the Surveillance, Epidemiology, and End Results (SEER) database compared to other published series. We observed that in the high incidence areas (North of Africa) when compared to "classical" breast cancer, IBC was associated to younger age (less than 50 years) with rapid evolution of signs and symptoms (in less than 3 up to 6 months), and more aggressive clinical and histopathological-molecular parameters, due to the predominance of triple-negative and HER2+ subtypes in around 60% of cases. An epidemiologic trend was observed in both high and low incidence areas since the eighties are towards reduction of IBC prevalence. Concerning Tunisia, in comparison with the historical series of the 1980s, the incidence decreased in part by applying more stringent diagnostic criteria but also probably due to a slight improvement of the socio-economic level (SEL). This trend was also observed in the US, due to the efforts of collaborative IBC groups from MD Anderson Cancer Center (MDACC), Duke and IBC patient advocacy groups. Therapeutic results are slightly better due to the standardization of a multidisciplinary approach and the use of combined primary chemotherapy and/or targeted therapies (especially in HER2 positive patients), followed by mastectomy plus radiotherapy. The 5-year overall and disease-free survival is at more than 60%, related to an IBC mortality decrease observed in the cohorts of patients treated in the last decade.

Inflammatory breast cancer (IBC) advocacy-Past, present and future!

Patient advocates, referring to those individuals that have been diagnosed with the disease for which they advocate, are essential stake holders in healthcare. For those facing the stages of being diagnosed with Inflammatory Breast Cancer (IBC), the "call to advocate" is an immediate response to being diagnosed with a rare and aggressive disease that progresses rapidly, often in a matter of weeks or months. There is a great stigma and bias in the medical community that has inhibited the education and study of IBC. A lack of understanding of the disease, how it presents and how to treat it leaves many IBC patients facing misdiagnosis. Communication is a cornerstone of healthcare; this goes beyond the patient-provider dynamic. Education of IBC must be a grassroots initiative. There should be no barrier to care in the diagnosis, treatment, study and survivorship of inflammatory Breast Cancer. It is not just an oncologist's lesson to learn, but that of all providers in healthcare. In this chapter you will hear how 4 women who were diagnosed with IBC faced the difficult tasks of navigating through the healthcare system on their own and came out on the other side using their experience to help others. In conclusion, in defining the evolving roles of Patient Advocacy in IBC over the past 25 years, we examine what has been done, along with its challenges, and what work still remains from the perspectives of different patient advocates.