Citations

Objectives/Goals: This project will enrich our understanding of basal breast carcinogenesis, highlighting the distinct biological differences in breast cancer risk between non-Hispanic Black (NHB) or non-Hispanic White (NHW) women, but also has the potential to provide real-world solutions thereby contributing to reducing health disparities in breast cancer outcomes Methods/Study Population: In the biological investigation, I am utilizing a unique cohort of normal breast tissues from Mayo Clinic patients who underwent breast reduction surgery that have self-identified as NHB or NHW premenopausal women. From these tissues, we are able to subculture human mammary epithelial cells, which we will use for our consequent experiments. For the qualitative study, I aim to recruit up to 40–50 eligible NHB women identified at increased risk for breast cancer and conduct semi-structured qualitative interviews informed by the National Institute on Minority Health and Health Disparities Research Framework. Results/Anticipated Results: Gene expression profiling on our cohort of 15 NHB and 40 NHW premenopausal women identified a gene expression signature in NHB women indicative of elevated Hedgehog signaling, a key factor in triple-negative breast cancer (TNBC) development and progression. I hypothesize that persistent activation of Hedgehog signaling within NHB women instigates the proliferation and transformation of basal stem cells within the breast, thus fueling TNBC development. Understanding the perceptions and experiences of NHB women that are identified as being at an increased risk for BC will aid in the identification of barriers and facilitators to their risk reduction care and in turn provide implementation strategies that could contribute to alleviating the racial disparity seen in TNBC morbidity, mortality, and preventative care. Discussion/Significance of Impact: The significance of this project lies in its dual approach, uncovering basal breast cancer mechanisms in a high-risk group using normal breast tissue and evaluating the perspectives from NHB women to enhance the practical relevance of our findings.

Summary Integrins are heterodimeric receptors important for cell adhesion and signaling. Integrin α5β1 is a key mediator of angiogenesis and its dysregulation is associated with tumor progression and metastasis. Despite numerous efforts, α5β1-targeting therapeutics have been unsuccessful due to poor efficacy and off-target effects. A contributing factor is our limited understanding of how integrin conformation influences interactions with therapeutics. Using cell-based functional assays, patient-derived xenografts, biophysics, and electron microscopy, we shed light on these relationships by characterizing two anti-α5β1 antibodies, BIIG2 and MINT1526A. We show that both antibodies bind α5β1 with nanomolar affinity, reduce tube formation in vitro , and bind overlapping epitopes that block fibronectin binding. However, using electron microscopy, we reveal that while BIIG2 binding does not substantially alter the conformational states, MINT1526A preferentially recognizes the bent conformation and restricts the conformational ensemble. These insights can guide which aspects to prioritize to improve the design of future integrin-targeted therapeutics.

ABSTRACTBackgroundData are limited on the natural history and symptom patterns of cyclic vomiting syndrome (CVS), a disorder of gut–brain interaction characterized by recurrent stereotypical vomiting, retching, and nausea episodes.MethodsA 6‐month, observational, remote study prospectively assessed symptom patterns in adults with CVS using an electronic daily diary. Patients recorded their disease experience, including CVS symptoms and associated severity, in the daily diary. The study defined a CVS episode start as the first day of 5 or more vomiting and/or retching (V + R) events. Episode end was defined as the first day of ≥ 7 (prespecified main analysis) or ≥ 4 (sensitivity analysis) days without any diary V + R events.Key ResultsEighty‐eight of 93 (94.6%) enrolled patients (62 female; mean age, 37.7 years) had daily diary data recorded during the study; 61 (69.3%) patients had at least one episode. In the prespecified main analysis, 191 episodes (median, 0.6 per 30 diary days) were reported (median duration, 3.0 days); 17.8% of the episodes lasted > 10 days. In the sensitivity analysis, 248 episodes (median, 0.7 per 30 diary days) were reported (median duration, 2.0 days). Thirteen of 88 (14.8%) patients with diary data had interepisodic V + R (reported V + R events without meeting the threshold for study‐defined episode). Other CVS‐related (non‐V + R) symptoms (most frequently nausea, abdominal pain, and sweating) were reported more frequently during the episode versus the interepisodic period.Conclusions and InferencesThis prospective longitudinal study shows marked heterogeneity of CVS episodes and highlights the need to better define and characterize episodes in these patients.

Abstract In 2003, the Institute of Medicine noted the need to improve workforce diversity. The American Society of Hematology (ASH) responded by developing the Minority Recruitment Initiative (MRI) to recruit diverse physicians/scientists into hematology. We evaluated the outcomes of the program. From 2004 to 2022, there were 405 awardees. Compared with national estimates, MRI awardees were less likely to discontinue their degree programs. MRI graduate student awardees had 0% attrition (97.5% confidence interval [CI], 10.6), whereas the national minority graduate student attrition was 36%. Medical student awardees had 2.2% (95% CI, 0.61-5.6) attrition, compared with the minority medical school attrition of 5.6%. Awardees were more likely than expected to pursue hematology-oncology (5.7% minority national estimate) because 14.4% (95% CI, 8.1-23.0) of medical student awardees and 88.5% (95% CI, 70.0-97.6) of early career awardees remain in the field. ASH has developed a successful program, but continued efforts are needed to advance equity in hematology.

Abstract Transcriptome profiling using RNA sequencing (RNA-seq) of bulk formalin-fixed paraffin-embedded (FFPE) tissue blocks is a standard method in biomedical research. However, when used on tissues with diverse cell type compositions, it yields averaged gene expression profiles, complicating biomarker identification due to variations in cell proportions. To address the need for optimized strategies for defining individual cell type compositions from bulk FFPE samples, we constructed single-cell RNA-seq reference data for breast tissue and tested cell type deconvolution methods. Initial simulation experiments showed similar performances across multiple commonly used deconvolution methods. However, the introduction of FFPE artifacts significantly impacted their performances, with a root mean squared error (RMSE) ranging between 0.04 and 0.17. Scaden, a deep learning-based method, consistently outperformed the others, demonstrating robustness against FFPE artifacts. Testing these methods on our 62-sample RNA-seq benign breast disease cohort in which cell type composition was estimated using digital pathology approaches, we found that pre-filtering of the reference data enhanced the accuracy of most methods, realizing up to a 32% reduction in RMSE. To support further research efforts in this domain, we introduce SCdeconR, an R package designed for streamlined cell type deconvolution assessments and downstream analyses.

Abstract Over 1 million women in the U.S. undergo radiologically guided percutaneous biopsies annually. Of these, 75% reveal benign breast disease (BBD), typically surrounded by normal breast lobules, which are proposed to reflect the biology of the breast parenchyma diffusely. With aging, normal lobules undergo involution, and delays in this process are linked to increased breast cancer (BC) risk. Because BBD patients are at increased risk of developing BC, and pathologic classification only stratifies risks among groups of patients, novel methods for individual BC risk prediction are needed to guide precision management. Prior literature has shown that most proliferating epithelial cells in normal lobules do not express estrogen receptor (i.e., ER-/Ki67+), whereas co-expression is frequent in BC precursors and in BCs (i.e., ER+/Ki67+). Thus we developed and applied a novel quantitative dual ER/Ki67 stain to BBD biopsies from the well-characterized contemporary Mayo Clinic BBD cohort (2002-2013) to assess differences by levels of lobular involution and tissue type (BBD vs. normal), as well as associations with BC risk. We identified 100 BBD biopsies preceding BC (cases) and 100 biopsies from cancer-free women (controls), frequency-matched on age and length of follow-up. A multiplex immunofluorescence assay was developed to detect ER/Ki67 coexpression in cytokeratin positive epithelial cells in normal lobules or BBD lesions in FFPE tissue sections. An inverse normal transformation was applied to cell counts and proportions and associations were assessed for levels of lobular involution, tissue type (normal lobule vs. BBD), and case status using t-tests and linear regression models. The final data set included 1152 normal lobules or BBD lesions in biopsies of 177 subjects (88 cases and 89 controls). In univariate analyses, normal lobules showing delayed age related involution included higher counts of ER-/Ki67+, ER+/Ki67- and ER+/Ki67+ cells, and the lowest proportion of ER+/Ki67- cells (p<0.03; all). In separate analyses comparing presence vs. absence, detection of any ER+/Ki67+ cells was suggestively more common in non-involuted vs. involuted lobules. Compared with normal lobules, BBD showed higher counts and proportions of ER+/Ki67- and ER+/Ki67+ cells and lower values for ER-/Ki67+ (all p<0.001). In these preliminary results, marker expression in normal lobules and in BBD did not differ by case-control status. Preliminarily, we find that ER+/Ki67+ cells are increased in normal lobules with delayed age-related involution and in BBD lesions, consistent with their associations with increased BC risk. These findings are consistent with the risk reducing effects of endocrine chemoprevention and may serve as useful biomarkers in prevention therapy. In this analysis, limited to only a few lobules and BBD lesions per biopsy, ER+/Ki67+ cell counts and proportions did not vary significantly by case-control status. Citation Format: Melody L. Stallings-Mann, Robert A. Vierkant, Stacey J. Winham, Bryan McCauley, Matt R. Jensen, Sophie Noel, Laura Pacheco-Spann, Celine M. Vachon, Amy C. Degnim, Derek C. Radisky, Mark E. Sherman. Measurement of ER and Ki67 coexpression in cytokeratin positive epithelial cells in benign breast disease (BBD) percutaneous biopsies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB328.

Abstract Background: Age-related lobular involution (ARLI), characterized by regression of breast epithelial tissue during the peri-and post-menopausal period, plays a crucial role in breast cancer risk. Delayed or incomplete ARLI is linked with increased postmenopausal breast cancer susceptibility.This study focuses on unraveling the molecular mechanisms of ARLI, drawing parallels with the well-characterized postpartum involution (PPI). Our aim was to discover biomarkers differentiating women who progressed through ARLI from those with stagnant ARLI. Methods: We utilized the Mayo Clinic Benign Breast Disease (BBD) cohort, analyzing 108 perimenopausal women aged 45-55 who had a subsequent benign biopsy between 2-15 years later. We assessed Lobular Involution (Ll) status by comparing the number and size of lobules in initial and subsequent biopsies. RNA profiling of initial biopsies was performed using NanoString 10360 and BC360, identifying differentially expressed genes between ARLI progression and stagnation. Immunohistochemistry (IHC) mapped the expression of these biomarkers in epithelial lobules. Results: We identified 37 genes with significant differential expression, highlighting Leukemia Inhibitory Factor Receptor (LIFR) as upregulated in ARLI stagnant samples. LIFR, part of the IL-6 cytokine signaling pathway, is known for its role in the induction of apoptosis during PPI via pSTAT3 activation. Our IHC analyses of initial biopsies of women who differentially progress through ARLI confirmed differential expression of LIFR that is coordinately regulated with pSTAT3. Conclusion: Our findings reveal significant parallels between ARLI and PPI. Future research will assess how LIFR/pSTAT3 signaling is linked to induction of apoptotic markers in perimenopausal women and will investigate how anomalies in the LIFR/pSTAT3 pathway might contribute to heightened breast cancer risk in women with delayed or incomplete ARLI. This study not only sheds light on the complex biological processes of aging in breast tissue but also opens new avenues for breast cancer risk assessment and prevention strategies. Citation Format: Jaida C. Lue, Derek Radisky, Melody Stallings-Mann, Mark Sherman, Amy Degnim, Bryan McCauley, Tanya Hoskin. Deciphering the link between aging, lobular involution, and breast cancer risk: The role of LIFR/pSTAT3 signaling [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 849.