Cancer Prevention Research Articles

Abstract PO2-25-01: Tumor Derived Chitinase-3 like 1 Induces Neutrophil Extracellular Traps that Promote T cell Exclusion and Resistance to Immunotherapies in Breast Cancer

Abstract Breast cancer remains the most prevalent cancer and a major cause of mortality affecting women worldwide. Chemotherapy along with radiation and surgery have long been the standard of care for breast cancer patients. However, devastating side effects, resistance to treatments and relapse are major concerns for patients and physicians. With the rise of immunotherapies as a treatment option for various cancers, there is a critical need to understand the mechanisms through which cancers evade the immune system. Targeting such mechanisms holds the key to improve patient response to immunotherapy, especially in breast cancer where efficacy rates remain low. In a subset of poor outcome Triple Negative Breast Cancers, cytotoxic T cells are excluded from the tumor nest and restricted to the surrounding stroma, a phenomenon known as stromal restriction. Our data from genetically engineered mouse models and human tumors identified that the secreted cytokine Chitinase-3 like 1 (Chi3l1) promotes stromal restriction of T cells in several tumor types including breast, lung and colon. Chi3l1 ablation in pre-clinical models of breast cancer results in increased T cell infiltration into the tumor nest which delayed mammary tumorigenesis and improved response to immunotherapy. We further demonstrate that Chi3l1 promotes T cell exclusion through the direct induction and deposition of neutrophil extracellular traps (NETs) which form a barrier that restricts T cell entry. Neutrophil depletion or pharmacological disruption of NET formation abrogates Chi3l1-induced T cell exclusion and histologically phenocopies Chi3l1 ablation. Thus, our results indicate that Chi3l1 is a major immunosuppressive cytokine that promotes breast cancer progression by inducing NET formation and inhibiting T cell infiltration. Given the importance of T cell infiltration in immune elimination of nascent tumors, the future targeting of Chi3l1 should improve immunotherapy efficacy and outcomes in patients with tumors characterized by a T cell excluded microenvironment. Citation Format: Tarek Taifour, Sherif Samer Attalla, Dongmei Zuo, Yu Gu, Virginie Sanguin-Gendreau, Hailey Dall-Proud, Emilie Solymoss, Tung Bui, Hellen Kuasne, Vasilios Papavasiliou, Chun Geun Lee, Suchitra Kamle, Peter Siegel, Jack Elias, Morag Park, William Muller. Tumor Derived Chitinase-3 like 1 Induces Neutrophil Extracellular Traps that Promote T cell Exclusion and Resistance to Immunotherapies in 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 PO2-25-01.

Abstract PO5-17-06: Prevalence of BRCA Mutations: A Predictive Model in a High-Risk Population of BC Patients at a Tertiary Care Center

Abstract Background: Breast cancer (BC) is a prevalent cancer in Saudi Arabia, with the majority of cases being sporadic. However, 25-30% of cases are associated with hereditary factors. Germline BRCA mutations are the most common mutations linked to hereditary BC predisposition syndromes, with a reported frequency of up to 11% in Saudi Arabia. Methods: This retrospective cohort study was conducted at a single institution in Saudi Arabia. Medical records of BC cases were reviewed where BRCA testing was performed, typically in patients with triple negative BC, hormone-positive (HR+) BC in younger premenopausal patients under the age of 45, or those with a personal or family history of BC. Patients meeting these criteria were diagnosed and treated at a tertiary care center in Saudi Arabia,between 2018 and 2021. The association between BRCA positivity and proposed risk factors was evaluated using chi-square analysis. Multivariate analysis was performed using logistic regression to assess the association between independent significant risk factors and BRACA+. Results: 482 cases of breast cancer were reviewed, with 412 testing negative for mutations and an overall BRCA positivity rate of 13.7%. Among BRCA positive patients, 62% had a positive family history (p-value < 0.001), and they tended to be younger, with a median age of 38 compared to BRCA negative patients with a median age of 42 (p-value = 0.01). Of the 469 female patients, 62 (13%) were BRCA positive, and of the 12 male patients, 3 (25%) were BRCA positive. Among the BRCA positive patients, 73% had BRCA1 mutations, and 26% had BRCA2 mutations. No patients with lobular BC tested positive for BRCA mutations. The odds ratio for BRCA positivity in triple negative BC was 3.6 (95% CI 2.1-6.2, p-value < 0.001). The odds ratio for BRCA positivity in HR+ cases was 2.5 (95% CI 1.4-4.2, p-value = 0.001). In HR+ cases, 4.6% had BRCA1 mutations, and 5% had BRCA2 mutations. In ER- cases, 20% had BRCA1 mutations, and 1.2% had BRCA2 mutations. Multivariate analysis revealed that increasing the age of diagnosis by one year reduced the chance of having BRCA positivity by 5% (p-value = 0.009). Having a positive family history increased the risk of BRCA positivity with an OR of 8 (95% CI 4-15.8, p-value < 0.001), and triple negative BC increased the risk of BRCA positivity with an OR of 4.1 (CI 2.2-7.5, p-value < 0.001). The model performance was evaluated using an AUC of 0.80. Conclusion: This study highlights the high prevalence of BRCA mutations in a high-risk population of BC patients. The proposed predictive model identified younger age, triple negativity, and a positive family history as independent predictors, with an AUC of 0.8. The study's predictive model suggest that these factors may be useful in identifying patients who are at increased risk of carrying BRCA mutations and could benefit from genetic counseling and testing. Citation Format: Kausar Suleman, Khalid Al-Khatib, Emaan Haque, Tusneem El Hassan, Abdullah Al Suwaidan, Sabah Alaklabi, Taher Twegieri, Adhar AlSayed, Dahish Ajarim, Meshari Al Zahrani, Syed Saad Akhtar, Osama Al Malik, Amal Al Hefdhi, Wafa Khayal, Sitah Al Zughaibi, Asma Tulbah. Prevalence of BRCA Mutations: A Predictive Model in a High-Risk Population of BC Patients at a Tertiary Care Center [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 PO5-17-06.

Micronutrient Status and Breast Cancer: A Narrative Review.

Breast cancer is one of the most common cancers worldwide, at the same time being one of the most prevalent causes of women's death. Many factors such as alcohol, weight fluctuations, or hormonal replacement therapy can potentially contribute to breast cancer development and progression. Another important factor in breast cancer onset includes micronutrient status. In this narrative review, we analyzed 23 micronutrients and their possible influence on breast cancer onset and progression. Further, the aim of this study was to investigate the impact of micronutrient status on the prevention of breast cancer and its possible influence on various therapeutic pathways. We researched meta-analyses, systemic and narrative reviews, retrospective studies, as well as original studies on human and animal models. The results of these studies indicate a possible correlation between the different levels of micronutrients and a decreased risk of breast cancer as well as a better survival rate. However, further studies are necessary to establish adequate doses of supplementation of the chosen micronutrients and the exact mechanisms of micronutrient impact on breast cancer therapy.

Actions speak louder than words; pediatricians, gynecologists, nurses, and other mothers' perspectives on the human papillomavirus vaccine: an Istanbul multicenter study.

Gynecologists and pediatricians have an essential duty to prevent cervical cancer. In this study, we compared the compliance of gynecologists (n = 22) and pediatricians (n = 49) with nurse/midwife (n = 66) and non-medical moms (n = 120) with regards to cervical cancer precautions. A questionnaire was used to gather data on their demographics, personal vaccination and screening practices, children's immunization status, and awareness of cervical cancer prevention. The findings demonstrated that gynecologists and pediatricians were better than others at understanding the risk factors and prevention of cervical cancer. It was noted that compared to other groups, physician mothers and their offspring had higher vaccination rates (n = 13, 18.3%; n = 10, 29.4%, respectively). Medical professionals typically provided thorough and accurate answers to informational questions. More frequent Pap smear tests were performed by gynecologists. It was noted that mothers who worked as pediatricians and nurses/midwives neglected their own screening needs. This questionnaire survey sought to ascertain Istanbul's health professionals' present opinions regarding HPV vaccination. Healthcare professionals should be the first to receive information on HPV vaccination and cervical cancer incidence reduction. The public could then readily use them as an example.

Abstract PO1-09-03: Clinical Impact of Multigene Panel Testing in Patients with a Personal or Family History of Breast or Ovarian Cancer Previously Negative for BRCA1/2 Genes

Abstract Rapid developments in cancer genetics and hereditary cancer risk assessments have enabled the identification of individuals at elevated risk for hereditary malignancies to guide enhanced cancer screening and prevention efforts. Multigene panel testing has emerged as the standard approach as emphasized in the National Comprehensive Cancer Network (NCCN) guidelines. The purpose of this study was to investigate the frequency of other pathogenic mutations identified through multigene panel testing in individuals who previously tested negative for germline BRCA1/2 and assess the clinical impact of panel testing. Patients either previously diagnosed with breast cancer or with a family history of breast or ovarian cancer that had also been seen by Oncology Genetics at a single institution and tested negative for BRCA1/2 genes but had not undergone prior multigene panel testing were invited via a letter to return for an additional genetic counseling visit to discuss multigene panel testing. Patients were also able to opt-in to a survey component of the study and received an email to fill out the Multidimensional Impact of Cancer Risk Assessment (MICRA) and Cancer Worry Scale (CWS). Surveys were completed prior to the initial genetic counseling appointment and repeated after discussion of the multigene panel test results. A total 24 women met with a genetic counselor of which 22 (92%) had a personal history of breast cancer, 1 (4%) had a family history of breast cancer, and 1 (4%) had a family history of ovarian cancer. The mean age was 52.6 years (range, 42-68) and 100% of women were Caucasian. Of the 24 women, 17 (71%) completed multigene panel testing. Of the women that underwent testing, 7 (41%) had negative results, 6 (35%) had variants of unknown significance (VUS), and 4 (24%) had a pathogenic mutation identified in another gene (CDKN2A, CHEK2, and CFTR). There was no significant change in MICRA or CWS scores after multigene panel results were reviewed in the 9 patients that completed both pre- and post-genetic testing surveys. The mean/median summary MICRA scores pre- and post-counselling were 30 (SD 12.4), median 26 (min 18, max 56), and 21.2 (SD 15.4), median 21 (min 3, max 43), respectively (p=0.19, Wilcoxon signed ranks test). The mean/median summary CWS scores pre- and post-counselling were 14.3 (SD 5), median 15 (min 7, max 24), and 13.6 (SD 2.59), median 14 (min 10, max 17), respectively (p=0.53, Wilcoxon signed ranks test). Of the 4 patients with newly identified pathogenic mutations, 2 started new screening protocols and 1 underwent a prophylactic mastectomy. In conclusion, multigene panel testing identified pathogenic mutations in a subset of individuals who previously tested negative for BRCA1/2 genes leading to changes in clinical management. The completion of multigene panel testing did not lead to a significant increase in MICRA or CWS scores. Key limitations of this study include a small sample size and an all Caucasian population. Citation Format: Devon Miller, Stephanie Pritzl, Angela Tess, Jessica Gooding, Lisa Barroilhet, Lori Dubenske, Kari Wisinski. Clinical Impact of Multigene Panel Testing in Patients with a Personal or Family History of Breast or Ovarian Cancer Previously Negative for BRCA1/2 Genes [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 PO1-09-03.

Abstract PO5-21-02: Breast cancer screening based on physical breast examination: ITABERAÍ randomized trial

Abstract Introduction: Approximately 70% of the Brazilian population depends on the public healthcare system (Sistema Único de Saúde - SUS). However, only 16% of SUS users have access to mammography for breast cancer screening, which necessitates the evaluation of new strategies to reduce mortality from the disease, including expanding physical breast examination (PBE) by non-medical professionals. Within the primary healthcare network, the Community Health Agent (CHA) is a technical-level professional who performs activities through home visits. The primary objective of this study is to evaluate the effectiveness of screening actions based on PBE performed by CHA in reducing advanced tumors (Stage III and IV) and breast cancer mortality rates. Secondary objectives include comparing the number of breast cancer diagnoses between the groups, establishing the overdiagnosis rate, comparing cancer-specific survival, comparing overall survival, comparing the number of diagnostic procedures, assessing the interval between the first symptom and diagnosis, evaluating the interval between diagnosis and the start of treatment, and comparing the financial cost of diagnosis and treatment for breast cancer patients. Trial design: Multicenter, phase III, prospective, randomized clinical trial. The target population comprises women aged 40 years or older and users of SUS. The randomization process will be carried out based on the spatial analysis of each participating center, using sociodemographic information on women from each macroregion to verify the homogeneity of data between groups. Intervention: After randomization, CHA in each group underwent training at different times. CHA in the CG received guidance on breast cancer screening and prevention according to Ministry of Health recommendations, while CHA in the IG received the same guidance and participated in theoretical and practical training for PBE (only female professionals). Variables and data collection: An application was developed to be installed on mobile devices, which the CHA used during home visits. The graphical interface of the application was developed in Dart/Flutter. For the backend, Python programming language was used along with the Flask framework to create the Application Programming Interface (API) responsible for the communication between the database and the application. The MySQL software was used for the relational database. The variables used for building the application included sociodemographic data, lifestyle habits, medical history, information on previous examinations, and physical breast examination. Statistical analysis: For the analyses, the database will be exported to the REDCap (Research Electronic Data Capture) platform. The calculations were defined to detect a reduction in severe cases and mortality (10% and 20%, respectively). For this purpose, a sample power of 80% and a Type I error of 5% were adopted after adjusting for intraclass correlation and sampling effect (0.032 and 1.892, respectively). The calculations were estimated using nQuery software (version 9.1). For the city of Itaberaí, a population of 1,894 women was estimated in each group, resulting in a total of 3,788. Present and target accrual: The trial was activated in December 2022, and as of June 30th, 2023, 2,467 patients had been accrued. The study will last for 16 years, and the first data analyses will be conducted in 2024. Registration and ethical aspects: The trial is registered in ReBEC (Brazilian register): RBR-39vm2nd. Contact information: Prof. Dr. Ruffo Freitas-Junior, Federal University of Goiás, ruffojr@terra.com.br. Citation Format: Ruffo Freitas-Junior, Danielle Rodrigues, Rosangela Corrêa, Leonardo Soares. Breast cancer screening based on physical breast examination: ITABERAÍ randomized trial [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 PO5-21-02.

Abstract PO4-19-02: Genetic risk estimation in breast cancer and assessing health disparities

Abstract Background: Breast Cancer (BC) incidence and the distribution of BC risk factors vary between racial and ethnic groups within the United States. It has been demonstrated that providing education on individualized breast cancer risk will improve patient uptake to recommended BC screening and prevention strategies. Most clinical risk assessment tools, including the validated IBIS model were derived from data using non-Hispanic white women. Consortia have also now identified over 300 common genetic susceptibility loci for BC, summarized by the polygenic risk score (PRS). When combined with clinical risk assessment tools, such as the IBIS or BCRAT models, the PRS can further refine risk estimation for patients. To date, most studies on the use of PRS have been done in non-Hispanic white women. While these PRS still perform well in racial minorities, there has been a recognized need to improve racial and ethnic diversity in genomic research cohorts. Herein, we aim to combine clinical risk assessment models that are already used in routine clinical practice with information derived from PRS testing in women of racial minorities to determine if this can improve risk estimation, patient understanding, and uptake to recommended breast cancer screening and prevention strategies. Design: This is a minimal risk prospective study with a single arm incorporating the PRS into a standard breast cancer risk reduction consultation, followed by annual surveys over 10 years to determine if and how the information provided by the PRS influenced patient decisions regarding recommended BC screening and prevention. Patients will have IBIS and BCRAT risks calculated at baseline visit. A survey of patient perceptions/understanding of risk, intention to undergo screening, and use of preventive medicine is completed after baseline visit prior to receiving the PRS results. Blood sample is obtained at baseline and DNA samples are analyzed for approximately 300 SNPs on a custom-designed, targeted SNP panel from ThermoFisher Scientific by the Mayo Clinic Genomics Laboratory. This PRS result is then combined with the clinical risk assessments (IBIS and BCRAT scores) using the R package Individualized Coherent Absolute Risk Estimators (iCare) tool to provide a new estimate of breast cancer risk for 5year, 10year, and lifetime risk. Patients are seen for follow-up to review results and then complete a second survey to assess their understanding of the results, BC risk, and how the PRS impacted their decision to undergo screening/prevention strategies. Eligibility Criteria: Women who self-identify as African American/Black or Hispanic/Latinx between 30-75 years old with any of the following: 1.)IBIS score of ≥5% for the 10 year risk OR BCRAT score of ≥ 3 % for the 5 year risk. 2.) History of biopsy proven atypical hyperplasia 3.) History of biopsy proven lobular carcinoma in situ. Specific Aims: Aim 1: The primary aim of this study is to explore if the addition of PRS to the BCRAT and IBIS score will improve intentions to undergo recommended breast cancer screening strategies such as mammography, MRI, or molecular breast imaging in women of underserved racial minorities Aim 2: To explore if the addition of the PRS to the BCRAT and IBIS risk score will aid women of racial minorities in deciding whether to take preventative endocrine therapy. Aim 3: To understand how individualized risk assessment and information on PRS may alter perceived risk of breast cancer. Statistical Methods Analysis will be mostly descriptive. Continuous variables will be summarized as mean (standard deviation) or median (range) and categorical variables will be reported as frequency (percentage). Kaplan-Meier method will be used to estimate the long-term cumulative risk of cancer. Current Accrual: 3. Target Accrual: 50 Citation Format: Lauren Cornell, Sandhya Pruthi, Linda Hasadsri, Sarah McLaughlin. Genetic risk estimation in breast cancer and assessing health disparities [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 PO4-19-02.

Abstract PO3-27-09: A Multidisciplinary Telehealth Approach to Breast Cancer Prevention in a Veteran Population

Abstract INTRODUCTION An estimated 13% of women will be diagnosed with breast cancer at some point in their lifetime. There are non-modifiable and modifiable risk factors including family history, genetics, obesity, and estrogen exposure. Interventions that reduce breast cancer risk and/or mortality include screening, chemoprevention, and lifestyle modification. A recent national survey shows that there are significant gaps in providing breast cancer prevention care for female Veterans. We describe the creation of a multi-disciplinary telehealth clinic aimed at reducing breast cancer risk in a high-risk female Veteran population. METHODS The breast cancer prevention clinic (BCPC) team consists of a medical oncologist, geneticist, genetic counselor, dietician, psychologist, and nurse navigator. High risk women are identified through a combination of screening questionnaires at annual mammography and genetics or primary care provider (PCP) evaluation, then referred to the clinic. Criteria for referral include age >=35, Gail 5 year risk >= 1.7%, Tyrer-Cuzick 10 year risk >= 5%, or history of thoracic radiation. At the BCPC telehealth visit, the medical oncologist makes individualized recommendations about chemoprevention by discussing the risks and possible complications of therapy. Use of screening magnetic resonance imaging (MRI) is also recommended to women with lifetime Tyrer-Cuzick score > 20%. Within the same visit, patients meet with a dietician to discuss nutrition modification, and a psychologist to address psychosocial barriers to lifestyle change. Those who start chemoprevention attend a 3 month follow-up with a nurse navigator to discuss tolerability and side effects. Subsequently, the patient’s PCP becomes responsible for management of chemoprevention and annual breast MRI. RESULTS Between January and December 2022, 33 patients were seen in BCPC. Patients had an average age of 52 years (range 42-70), Gail 5-year score of 2.53%, Tyrer-Cuzick 10-year score of 6.65%, and Tyrer-Cuzick lifetime score of 21.5%. Thirteen patients (39.4%) started chemoprevention, the majority of which were selective estrogen receptor modulators (SERM). Nine reported starting the medication at the 3 month follow-up appointment. The most reported side effect was hot flashes in 67%, although only the majority had mild symptoms. Three reported weight gain and one reported vaginal dryness. None reported worsening arthralgia or fatigue. Despite the low incidence of severe symptoms, only 3 continued to fill the medication at the time of chart review in August 2023. Twenty (60.6%) patients did not initiate chemoprevention. Four (20%) did not qualify due to cardiovascular or thrombotic risk factors, and three (15%) did not qualify due to concurrent use of hormone replacement therapy. Two (10%) elected not to start chemoprevention because they were planning for risk reducing mastectomies. Eleven (55%) did not initiate chemoprevention due to patient preferences and concern for side effects. Twenty-eight patients were recommended to obtain breast MRI in addition to mammogram for yearly screening. At time of chart review, 15 had at least one screening breast MRI ordered by PCP after BCPC visit, with 10 MRIs performed. CONCLUSIONS The unique interdisciplinary model of our breast cancer prevention clinic allows for a comprehensive and personalized evaluation for high-risk female Veterans on interventions to reduce their breast cancer risk. However, the current model does not ensure long-term compliance with these interventions. Studies have shown that more frequent/short-term follow up may improve compliance with endocrine therapies. Future directions include clinic expansion and providing additional follow-up with the multidisciplinary team to promote continued adherence to BCPC interventions. Citation Format: Hanqing Shang, Sarah Ansari, Shweta Dhar, Mahdieh Irranejadparizi, Stacey Edwards, Jessica Honkomp, Meagan Siehr, Bethany Aiena, Mary Nikityn, Diana Bearden, Deleene Menefee, Sita Bushan. A Multidisciplinary Telehealth Approach to Breast Cancer Prevention in a Veteran Population [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 PO3-27-09.

Abstract PS07-01: Exemestane and breast cancer prevention: how low can we go? Drug and biomarker tissue levels in a randomized presurgical trial on exemestane alternative dosing regimen

Abstract Exemestane is an effective drug to reduce breast cancer risk reaching an overall 65% reduction in breast cancer in the placebo–controlled phase III MAP.3 trial. To improve its acceptability in primary prevention programs, we are seeking the minimal effective dose. In a 3-arm presurgical trial of 4-6 weeks before breast surgery in 180 postmenopausal women with ER-positive breast cancer, we investigated the activity of alternative exemestane schedules: 25 mg per day (QD), 25 mg three times/week (TIW) or 25 mg per week (QW) and showed that in adherent participants TIW was not inferior to QD in reducing circulating estradiol (Serrano et al JAMA Oncol. doi:10.1001/jamaoncol.2023.0089). Moreover, Ki67 reduction was seen in all arms with no significant difference among arms. Here, we analyzed the concentration of sex steroids, exemestane, and its main metabolite in the cancer and adjacent non-cancerous breast tissue. Tissues samples were homogenized before liquid-liquid extraction. After reconstitution, samples were analyzed by coupling liquid chromatography with tandem mass spectrometry (Sciex QTRAP 6500, Nexera system, Shimadzu). We obtained breast cancer tissue from 93 and non-cancerous breast tissue from 117 participants to measure exemestane, 17-OH-exemestane, and sex steroids. Exemestane and 17-OH-exemestane concentrations were detectable only in the QD arm, while in TIW and QW arms levels were below the Lower Limit of Detection (< LLD). Median exemestane level was 3807 fmol/g and 17485 fmol/g and median 17-OH-exemestane level was 338 fmol/g and 1343 fmol/g in cancer and non-cancerous tissue, respectively. Interestingly, drug and its metabolite accumulated 4-5-fold in non-cancerous tissue compared to cancer tissue in the QD arm. Despite the between-arm drug concentration difference, estradiol was almost completely suppressed in all arms in the non-cancerous tissue, attaining level < LLD in QD and TIW arms, and barely detectable in QW arm. The median in the QW arm was < LLD (< LLD, interquartile range < LLD, 25.5 fmol/g) showing no differences in QD vs TIW and QD vs QW (p = 0.364 and p = 0.693 respectively). While a dose-response trend was observed in cancer tissue, estradiol level was < LLD (< LLD,52.2 fmol/g) on QD, 17.1 (< LLD, 125.3) on TIW, and 128 (< LLD, 224.8) on QW (p=0.046 QD vs TIW arms). Estrone showed a clear dose response trend among arms, whereas no differences were observed for testosterone and androstenedione for both cancer and non-cancerous tissue in all arms. The Ki-67 change was analyzed in the previous paper; here we report the data for those patients who had drug and hormones tissue concentration measured, where Ki-67 decreased in all arms: median Ki67 change from baseline was QD -8 (-10, -3), TIW -6 (-11, -2), QW -4 (-8, -1). Conclusions: Exemestane 25 mg three times a week maintains comparable activity to the standard dose on tissue estradiol suppression and Ki67 decrease. Considering the estradiol suppression in non-cancerous tissue of the lowest exemestane dose, QW might even be considered for breast cancer risk reduction in primary prevention. Further analyses are ongoing to investigate the correlation with other biomarkers including the role of polymorphic UGT2B17 genotype that could identify candidates to lower exemestane dosage. Citation Format: Davide Serrano, Harriet Johansson, Bjørn-Erik Bertelsen, Gunnar Mellgren, Parijatham Thomas, Katherine Crew, Nagi B Kumar, Debora Macis, Valentina Aristarco, Aliana Guerrieri Gonzaga, Sara Gandini, Mauro D’Amico, Tania Buttiron Webber, Irene Maria Briata, Stefano Spinaci, Viviana Galimberti, Giuseppe Viale, Lana A. Vornik, Eduardo Villar-Sanchez, Powel Brown, Brandy M Heckman-Stoddard, Eva Szabo, Bernardo Bonanni, Andrea De Censi. Exemestane and breast cancer prevention: how low can we go? Drug and biomarker tissue levels in a randomized presurgical trial on exemestane alternative dosing regimen [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 PS07-01.

Abstract PO1-08-03: Using Telehealth to Establish a High Risk Cancer Prevention Clinic over a large Geographic Area

Abstract There are health disparities in breast cancer screening based on urban, rural or frontier geographic designations. For instance, in Utah, the percentage of women who had no mammography in the last two years was 33.5% for urban, 33.8% for rural and 40.4% for frontier designations. Rural women are also diagnosed with breast cancer at later stages. Diagnosing breast cancer at earlier stages leads to improved survival, more affordable care, less toxic treatments, better quality of life and less time away from home and work. We are presenting the innovative use of telehealth to establish a High Risk Cancer Prevention Clinic to effectively reach a large geographic area and mitigate obstacles to accessing care. The clinic's mission is to identify and care for individuals with increased cancer risk due to familial, genetic and/or high risk lesions. This initiative provides centralized comprehensive evaluation, counseling and screening planning as well as referral for risk-reducing interventions closer to home. With a collaborative approach involving surgical and medical oncology, genetics, radiology and women's health specialists, the teleclinic has successfully served 280 patients since Spring 2022. Recently our health care system has increased significantly in geographic reach due to mergers with other health systems. We think this teleclinic is nimble enough and easily scalable to accommodate caring for increased numbers of patients needing this service. Citation Format: Maricel Purcell, Teresa Reading, Ginger Lee, Jennifer Tittensor, Margaret VanMeter. Using Telehealth to Establish a High Risk Cancer Prevention Clinic over a large Geographic Area [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 PO1-08-03.

Abstract PO4-20-01: A PROSPECTIVE PILOT STUDY OF MAMMOGRAPHIC PREDICTION OF WOMEN’S RISK (M-POWER) IN NIGERIA

Abstract Background There have been no sustained efforts at stemming the rising incidence and mortality from breast cancer in sub-Saharan African countries like Nigeria. Mammography is the gold standard for breast cancer screening and is associated with improved survival particularly among women 50 to 69. Reports from various parts of Nigeria show very low mammography screening uptake. Causes include lack of geographical access, financial issues (less than 5% of the population is covered by the National Health Insurance Scheme), lack of awareness and the increasing expertise gap from the continued brain drain, despite the already low number of radiologists in the country. Given these obstacles, our long-term goal is to devise a rational basis for identifying mammographic risk categories so that this resource can be deployed cost-effectively. We propose to carry out a 5-year prospective mammographic study in Nigerian women and to use machine learning to develop a risk prediction algorithm, so that following a single screening mammogram, the appropriate frequency of subsequent mammograms can be determined. Our immediate goal is to examine the feasibility of performing such a study. To this end, we have initiated a cross-sectional pilot study that will recruit up to 2000 women in multiple urban centers in Nigeria. Objective: To explore feasibility of creating a digital mammography image database representative of the radiological features of the breast of Nigerian women. Objective: To explore feasibility of creating a database that can be used to inform a predictive mammographic risk model for breast cancer and identify the appropriate population that will benefit from breast cancer screening in Nigeria. Design This is a prospective, open-label, cross-sectional pilot study in 2000 eligible women in Nigeria and will include a single screening mammography examination. The mammography images will be read by the study radiologist. The Pilot phase will determine the feasibility and aid in the design of the of the Extension phase in which up to 20,000 participants will undergo yearly mammography examination for 5 years. Incident cases of breast cancer during the study period will permit the development of deep learning algorithms for predicting the risk of breast cancer in this population. Main Eligibility Criteria: Inclusion Criteria All consecutive women aged ≥40 years and < 65 years presenting for screening mammography at the participating institutions will be eligible. Signed study-specific written informed consent. Exclusion Criteria Complaint of a focal dominant lump or a bloody or clear nipple discharge. History of breast implants. Any woman who is pregnant or has reason to believe that she might be pregnant. Statistical Methods Analyses of continuous data will be summarized using descriptive statistics where the following parameters will be reported: Number of observations, Number of missing observations, Mean, Median, Standard deviation (SD), Minimum (Min), Maximum (Max) Categorical data will be presented with absolute and relative frequency (n and %). Present Accrual and Target accrual Two hundred ninety-six women have been enrolled and screening digital mammographic images using GE Digital mammography equipment have been obtained on all participants at 2 study sites in 2 cities in Southern Nigeria. The target accrual is 2000 participants over 12 months. Conclusion Our preliminary experience to date suggests the feasibility of proceeding with a larger prospective study to define mammographic risk groups in Nigerian women which will permit the rational allocation of resources for breast cancer prevention activities in this underserved population. Contact Information: Dr Toyin Shonukan at tshonukan@yemanjacancercare.org Citation Format: Oluwatoyin Shonukan, Hyelakumi Ibrahim, Esther Udoh, Wahab Egbeolu, Kanyinsola Oyeyinka, Jonas Haggstrom. A PROSPECTIVE PILOT STUDY OF MAMMOGRAPHIC PREDICTION OF WOMEN’S RISK (M-POWER) IN NIGERIA [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 PO4-20-01.

Abstract PO5-11-07: Short- and long-term treatment-related effects on physical health in breast cancer survivors

Abstract Background. Breast cancer (BC) survivors experience greater physical health declines compared to cancer-free women of the same age, which is thought to be caused by their cancer and its treatment. However, the short- and long-term effects of different types of treatment on physical health are not well understood, especially for hormone therapy. Moreover, whether specific aspects of physical health, such as activities of daily living (ADL), are affected by treatment is unknown. Methods. This analysis was conducted in the Cancer Prevention Study 3 (CPS-3), a prospective cohort study with approximately 300,000 participants enrolled between 2006-2013. Participants returned a baseline survey and triennial follow-up surveys beginning in 2015. Incident, non-metastatic, female BC patients were included in this analysis if they returned a survey at least 90 days after their diagnosis through June 30, 2020, the end of follow-up for this analysis. All 2,551 BC patients included in this study had pre- and post-diagnostic surveys and underwent breast surgery if they were diagnosed with invasive disease. They were matched to up to five cancer-free women on age and year of survey returns (N=12,704). Self-reported physical health and ADL were assessed using the Patient-Reported Outcomes Measurement Information System (PROMIS) Global Health Scale instrument. Treatment information was obtained from cancer registries and self-report and included surgery, chemotherapy, radiation and hormonal therapy. Odds Ratios (OR) and 95% confidence intervals (CI) between treatment received and self-reported physical function were estimated using multivariable ordinal logistic regression models at three time points relative to the case’s diagnosis date: before diagnosis, within 90 days to 5 years after diagnosis, and more than 5 years after diagnosis. Results. Median age at diagnosis was 56 years (interquartile range (IQR): 50-62). Approximately 82% of the tumors were hormone-receptor positive. The median times from the three physical health measurements to diagnoses were 1.7 years before diagnosis (IQR: 0.9 – 2.7), 1.7 years (IQR: 0.9 – 2.5) from 90 days to 5 years post-diagnosis and 6.6 years (IQR: 5.5-7.0) for more than 5 years post-diagnosis. There was a significant risk of physical decline within 5 years of diagnosis for women who received chemotherapy or hormonal therapy compared to cancer-free women (Table 1). However, more than 5 years after diagnosis, the risk of physical decline was only observed among those who received chemotherapy. Treatment combinations that included chemotherapy were also associated with a decline in the ability to carry out ADL during the first 5 years. Patients who received hormonal therapy without chemotherapy were comparable to cancer-free women in their ability to carry out ADL during the post-diagnosis period. BC patients who received surgery only or surgery and radiation reported physical health and ADLs similar to cancer-free women within 5 and >5 years after diagnosis. Conclusions. Post-diagnosis physical health decline is time and treatment dependent. Patients receiving chemotherapy have the greatest overall physical health decline and it is long-lasting. Beyond five years from diagnosis, physical health of breast cancer patients who did not receive chemotherapy were similar to cancer-free women. Strategies are needed to help BC patients receiving chemotherapy overcome the long-term physical function limitations of their cancer treatment. Table. Associations between treatment received and physical health and ability to carry out activities of daily living. OR: Odds Ratio; CI: confidence interval; chemo: chemotherapy; radio: radiation therapy; horm: hormonal therapy. *Associations were adjusted for matching factors, which included age and time from diagnosis to measurement of physical health. Citation Format: Clara Bodelon, Matthew Masters, Lauren McCullough, Alpa Patel, Lauren Teras. Short- and long-term treatment-related effects on physical health in breast cancer survivors [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 PO5-11-07.

Abstract PO5-09-02: Breast Tissue Proteomic Profile of Breast Cancer in Premenopausal Women and Association with Mammographic Breast Density

Abstract Introduction: Breast cancer incidence is rising in premenopausal, hence, there is a critical need to understand factors underlying premenopausal breast cancer development in order to guide targeted prevention. Mammographic breast density is a strong risk factor for, as well as an intermediate phenotype for premenopausal breast cancer. Yet, the molecular mechanisms underlying the associations of dense breasts with breast cancer are not well understood. Our objectives in this study are to perform proteomic analysis in breast tissues to (i) identify proteins that are associated with breast cancer development in premenopausal women; (ii) determine which of these proteins are also associated with dense breasts. Methods: We performed proteomic analysis on tumor and adjacent normal tissues from 50 premenopausal women with breast cancer who had breast tissue samples archived at the St. Louis Breast Tumor Registry. Samples were analyzed on Orbitrap Eclipse Tribrid coupled with Vanquish Neo LC system (Thermo Fisher Scientific). Database search was performed using MaxQuant and MS1 LFQ intensities were used for further data analysis. We performed multiple imputation using Bayesian Principal Component Analysis and hierarchical clustering analysis using ‘ConsensusClusterPlus’ package in R. Pathway enrichment analysis was performed using Reactome Pathway database. 10 times repeated 5-fold cross validation using Logistic Regression (LR) was performed for model development. Top 10 proteins were selected by variable importance in logistic regression, and recursive feature elimination was performed for feature selection. We corrected for multiple testing by setting the false discovery rate, FDR, p-value < 0.05. Results: After imputing for missing values, we identified 3,571 proteins that were expressed in tumor and normal breast tissues. We selected 1,640 proteins for further analysis using median absolute deviation analysis. In multivariable-adjusted analysis, 451 proteins were up-regulated, and 180 proteins were down-regulated in tumor tissues compared to adjacent normal tissues (FDR < 0.05). 53 of the 451 proteins that were upregulated in tumor tissues were also upregulated in dense breasts. Some of the top proteins that were upregulated in both tumor tissues and dense breasts were AIMP2, ALDH18A1, BZW1, CKAP5, COPG1, ERGIC1, GSPT1, ILF2, IPO7, LRBA, and PSMD12. Mammographic breast density protein clusters were highly correlated with hormone receptor positivity clusters and were enriched in ESR-mediated signaling, IGF1R signaling, NOTCH4, PTEN regulation, and NFkB pathway. Discussion: Using untargeted proteomics, we identified proteomic signatures of breast cancer development in premenopausal women. We further identified protein biomarkers and pathways that are shared between breast tumors and dense breast tissues in premenopausal women. Our novel findings highlight mammographic breast density as a strong intermediate phenotype that can be targeted in breast cancer prevention in premenopausal women. Larger studies are needed to validate our findings. Citation Format: Shaili Tapiavala, Minsoo Son, Graham Colditz, Ah Young Goo, Adetunji Toriola. Breast Tissue Proteomic Profile of Breast Cancer in Premenopausal Women and Association with Mammographic Breast Density [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 PO5-09-02.

Abstract PO5-12-02: Landscape analysis of oncology nutrition research among patients being treated for breast cancer

Abstract The American Institute for Cancer Research/World Cancer Research Fund and the American Cancer Society regularly conduct systematic reviews on the evidence supporting nutrition interventions during cancer treatment. These reviews have found that the evidence to support clinical oncology nutrition practice guidelines is limited. It is unclear how many oncology nutrition studies are currently being conducted, especially among patients being treated for breast cancer. The goal of this project was to conduct a landscape analysis of nutrition research being conducted among breast cancer patients over the past 10 years. Methods: This analysis was part of a larger effort to describe the oncology nutrition research landscape for all cancer sites. Searches of ClinicalTrials.gov were performed on 1/8/2023 using the following search terms/combinations: “cancer AND nutrition”, “cancer nutrition”, “oncology AND nutrition”, “diet AND cancer”, “cancer, oncology, neoplasms, nutrition, diet”. Search results were downloaded as .csv files and uploaded to RStudio for merging and data cleaning (elimination of duplicates, and exclusion of studies registered in ClinicalTrials.gov before 1/1/2013 or after 12/31/2022). The resulting harmonized dataset was then uploaded to REDCap, and each entry was reviewed for eligibility by one of the authors. To be included in this landscape analysis, studies must have included data collection from patients who were actively receiving cancer treatment at the time of the study and the study had to be first posted to ClinicalTrials.gov between 1/1/2013 and 12/31/2022. Studies were excluded if they: 1) focused on the role of diet in primary cancer prevention, 2) focused on cancer survivors who had completed primary treatment for their cancers. Following eligibility review, the study datafile was returned to RStudio for further cleaning and analysis. Results: The initial ClinicalTrials.gov search identified 4,345 unique study listings. After review, 1,267 studies met the inclusion criteria, of which 132 (10.4%) studies were specific to breast cancer (117 intervention studies and 15 observational studies). Among breast cancer studies, reasons for exclusion were: study focused on diet/nutrition in the prevention of a primary cancer diagnosis (n=40), study participants had already completed their cancer treatment (n=128), study did not include a diet/nutrition intervention or assessment (n=31). The largest number of breast cancer specific studies were based in the United States (n=55, 41.6%), Italy (n=11, 8.3%), France (n=10, 7.6%) and Canada (n=9, 6.8%). Dietary supplement interventions were the most common type of intervention (n=50 studies, 42.7%), followed by behavior change interventions (n=22, 18.8%), diet in relation to a drug intervention (n=25, 21.4%), diet in relation to a device/procedure/radiation intervention (n=16, 14%), fasting/time-restricted feeding studies (n=13, 11.1%) and ketogenic diet interventions (n=3, 2.6%). Changes in weight or body composition (n=52, 39.4%), quality of life (n=45, 34.1%), adverse events (n=24, 18.2%), survival (n=20, 15,2%) and fatigue (n=17, 12.9%) were the most common outcome measures. Sixteen (12.1%) studies were supported by NIH funding and 9 (6.8%) studies were industry funded, although the majority (n=124, 93.9%) reported funding from “other” sources. Of the 41 studies that started between 2013-2017 (five years prior to the January 2023 ClinicalTrials.gov search), only 21 (51.2%) were listed as being “completed” and of those, only 7 were listed as “has results”. Conclusion: More research is needed to support evidence-based supportive care guidelines for oncology nutrition interventions during breast cancer treatment. Efforts should be made to support researchers in completing studies and disseminating research findings. Citation Format: Kim Robien, Heather Wopat. Landscape analysis of oncology nutrition research among patients being treated for 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 PO5-12-02.

Abstract PO3-01-10: Changes in Patient-Reported Outcomes with 3 Months of Pre-operative Endocrine Therapy in the POWER Trial

Abstract Background: The Pre-Operative Window of Endocrine Therapy to Inform Radiation Therapy Decisions Trial (POWER, NCT04272801) aims to determine whether 3 months of pre-operative endocrine therapy (pre-ET) affects decision-making regarding adjuvant radiation therapy (RT) among older women with early-stage, estrogen receptor (ER) positive breast cancer. The goal of the present study is to evaluate changes in patient-reported outcomes (PROs) during the course of pre-ET. We hypothesize that PROs will change over the course of pre-ET and that those changes can be used to identify patients who are at-risk for long-term noncompliance to adjuvant ET and who may benefit from RT. Methods: Participants in the POWER Trial receive 3 months of pre-ET prior to breast-conserving surgery and final treatment decisions regarding adjuvant RT. Health-related quality of life (HRQOL) (EORTC QLQ-C30 and QLQ-BR23), depression (Center for Epidemiologic Studies Depression Scale Revised), and general symptom burden (Breast Cancer Prevention Trial Symptom Checklist (BCPT-SCL)) are assessed at baseline and at day 90 after pre-ET. Perceived sensitivity to medicine (Perceived Sensitivity to Medicine (PSM) survey) is assessed at baseline. The BCPT-SCL was used to examine common ET side effects, including hot flashes, musculoskeletal symptoms, cognitive problems, weight gain, and bladder control. Graphical methods are used to display results. Results: The first 46 participants who completed pre-ET in the POWER trial were included in this preliminary assessment. From baseline to day 90, there was notable variability in HRQOL and no definitive shift towards worsening HRQOL with a median change (IQR) of 0 (-8.33, 8.33). Similarly, the median change in symptom profiles for the whole cohort was 0 over the 90 days of pre-ET. However, a subset of patients experienced changes in symptom burden throughout the 90-day period. Approximately one-fourth of participants reported an increase in hot flashes and musculoskeletal symptoms from baseline to day 90. There does not appear to be worsening fatigue, depression scores, cognitive problems, or weight gain. After stratifying by self-perceived sensitivity to medicine, patients with high PSM scores have a greater median change (0.5 and 0.33) in symptoms compared to those with low PSM scores (0 and 0) for hot flashes and musculoskeletal symptoms, respectively (Figure 1). Conclusions: When looking at this cohort, there was no change in symptoms or quality of life after the 3-month course of pre-ET. Evaluation of the changes in PROs identified a subset of participants with worsening symptoms after pre-ET. Future analyses, when trial accrual is complete, will examine the relationship between PROs and long-term adherence to adjuvant ET and will elucidate if the patients who experience worsening BCPT-SCL symptoms during the 90-day period are more likely to opt for RT. Figure 1 Change in symptoms after pre-ET Change in hot flash burden and musculoskeletal symptom burden is greater in patients with high perceived sensitivity to medicine. Citation Format: Trish Millard, Lena Turkheimer, Christiana Brenin, David Brenin, Patrick Dillon, Einsley Janowski, Anneke Schroen, Gina Petroni, Shayna Showalter. Changes in Patient-Reported Outcomes with 3 Months of Pre-operative Endocrine Therapy in the POWER Trial [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 PO3-01-10.

Abstract PS07-06: A novel citrullinated-ENO1 peptide-based vaccine for triple-negative breast cancer prevention

Abstract Purpose: To evaluate the merits of a novel citrullinated-enolase 1 (ENO1) peptide-based vaccine for inducing an effective response against triple negative breast cancer (TNBC). Background: Targets for cancer vaccines have included mutated proteins and peptides, as well as proteins that are overexpressed in cancer but otherwise ubiquitous in their structure. However, protein modifications other than mutation may also induce an immune response. Several lines of evidence have demonstrated a role for the posttranslational modification (PTM) citrullination as inducing immunogenicity. Dysregulated protein citrullination by peptidyl arginine deiminases (PADI) has been associated with autoimmune diseases and is currently being explored for its relevance to cancer. Previously, our group established PADI2, which catalyzes the PTM from arginine to citrulline, to be highly expressed in TNBC compared to normal mammary and other tissues. We observed that PADI2-associated protein citrullination promotes antigenicity. Importantly, we demonstrated that protein citrullination, non-occurring in DNA and RNA-based vaccines, is highly cancer specific. On the basis of these findings, we developed a novel vaccine based on cancer-selective citrullinated-enolase 1 peptides (cit-ENO1) that were identified from mass spectrometry surfaceome and immunopeptidome data from breast cancer cells. We assessed the extent to which a citENO1 peptide based vaccine elicits a potent host response and attenuates tumor development in a syngeneic mouse model of TNBC. Design: To confirm that the cit-ENO1 peptide vaccine elicited an immune response, we immunized female B6129SF1/J mice with 10nmol cit-ENO1 peptides or 10nmol of corresponding unmodified peptides as the antigen, plus the TLR3 agonist poly I:C as an adjuvant (10mg), subcutaneously once a week, for three weeks. Saline or the adjuvant alone were used as controls. One week post the last round of immunization, draining lymph nodes (LNs) and immunized skin were harvested, and T cell phenotypes evaluated using flow-cytometry. To assess anti-cancer efficacy, female B6129SF1/J mice were immunized with cit-ENO1 peptides or unmodified peptides with poly I:C as an adjuvant followed by orthotopic implantation with murine BRCA1co/co; MMTV-Cre; p53+/- TNBC cells (1.5 x 106) and tumor growth as well as overall survival were assessed. Results: We observed that the cit-ENO1 peptide vaccination induced a statistically significantly greater percentage of activated CD8+ PD-1+ effector T cells as well as CD8+ CD44+ CD62L- effector memory T cells in the LNs compared with either the control groups or the unmodified ENO1 peptide. CD8+ PD-1+ T-cells were also found to be significantly elevated in immunized skin of cit-ENO1 vaccinated mice. Both cit-ENO1 and unmodified ENO1 vaccine increased CD4+ PD-1+ T cells from the LNs and immunized skin. Remarkably, the cit-ENO1 vaccine but not the unmodified-ENO1 vaccine significantly delayed tumor growth and markedly improved overall survival compared to respective controls (Logrank test for trend 2-sided p< 0.05). Conclusion: We have developed a novel vaccine based on cancer-selective cit-ENO1 peptides that stimulates a potent anti-cancer immune response and significantly delays tumor initiation and progression in a preclinical, immune competent mouse model of TNBC. Importantly, the anti-cancer effects were not observed with corresponding unmodified ENO1 peptides. Citation Format: Ricardo Leon Letelier, Hiroyuki Katayama, Yihui Chen, Yinning Cai, Fuchung Hsiao, Banu Arun, Samir Hanash. A novel citrullinated-ENO1 peptide-based vaccine for triple-negative breast cancer prevention [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 PS07-06.

Abstract PO2-10-09: Professional Support for Eating and Nutrition among Women Living with Breast Cancer: Implications for Mental Health and Quality of Life

Abstract Background: Within oncology, nutrition and eating behaviors are often tied to cancer prevention, incidence rates, progression, and healthy survivorship, as well as symptom and side effect management. While many nutrition-related resources and guidelines focus on physical health outcomes, support around nutrition and eating behaviors can have critical implications for mental health and quality of life outcomes among breast cancer patients and survivors. Methods: 232 women with breast cancer enrolled in the online Cancer Experience Registry and provided sociodemographic and clinical characteristics, answered questions about their eating and nutrition experiences, including utilization of a Registered Dietitian for professional eating and nutrition support since being diagnosed with cancer, and completed the Patient-Reported Outcomes Measurement Information System (PROMIS-29v2.0 + 2-item Cognitive Function Short Form). Frequencies were calculated and group differences among those who wanted professional support for eating and nutrition but either did or did not receive it were assessed using independent-samples t-tests. Results: The sample was 81% Non-Hispanic (NH) White, 9% NH Black. Participants varied in age (mean=61 yrs; SD=9.2), time since diagnosis (median=7 yrs, range: < 1-39) and socioeconomic status (16% household income < $40K; 32% employer-provided insurance coverage). 44% were currently receiving treatment, with 70% in remission, 12% with metastatic disease, and 21% with history of recurrence. Over one-third (36%) received professional support for eating and nutrition from a Registered Dietitian since being diagnosed with cancer, including 12% receiving that support in the last 6 months. Participants wanted professional support for eating and nutrition during active treatment (51%), after treatment (44%), at initial diagnosis (23%), before treatment (18%), before being diagnosed with cancer (11%) . The most commonly reported eating and nutrition needs driving the desire for professional support included weight-related support (54%; maintenance, gain, or loss), achieving healthy eating patterns (52%), increasing energy level (46%) and physical fitness/strength (45%). However, experiences with professional support for eating and nutrition varied: 54% wanted eating and nutrition support since being diagnosed with cancer, but only 68% of those who wanted this support were able to access care. Irrespective of access to professional eating and nutrition support, participants report changing their eating patterns to manage SSEs (50%) or improve long-term health (57%). Among those who desired professional support for eating and nutrition since being diagnosed with cancer (n=102), those who did not get the desired support (n=34) compared to those who did (n=68) reported higher levels of anxiety, depression, sleep disturbance, and pain, as well as lower levels of physical and cognitive function (all ps < .05). Levels of fatigue and social function were not significantly different between groups. Conclusion: While there is a strong desire for professional support surrounding eating and nutrition among women with breast cancer, when that support is needed and what it aims to address varies greatly. Among those interested in receiving professional support for eating and nutrition, those who accessed professional support reported greater mental health and quality of life. Further research is needed to understand barriers to accessing eating and nutrition support among those who are not able to obtain it. Community-based advocacy organizations that offer access to professional support services for eating and nutrition are critical for addressing unmet needs in this area to improve health and well-being among women with breast cancer. Citation Format: Victoria Morris, Melissa Miller, Susan Weldon, Gail Kelly. Professional Support for Eating and Nutrition among Women Living with Breast Cancer: Implications for Mental Health and Quality of Life [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 PO2-10-09.

Regulation of iodine-glucose flip-flop in SW1736 anaplastic thyroid cancer cell line.

The alternative manner of iodide and glucose uptake found in different types of thyroid cancer, referred to flip-flop. ATC cells indicate low iodide uptake and high glucose uptake, which lack the morphology and genetic characteristics of well-differentiated tumors and become increasingly invasive. Importance placed on the discovery of innovative multi-targeted medicines to suppress the dysregulated signaling in cancer. In this research, we aimed to clarify molecular mechanism of Rutin as a phytomedicine on anaplastic thyroid cancer cell line based on iodide and glucose uptake. The MTT test was employed to test cell viability. Iodide uptake assay was performed using a spectrophotometric assay to determine iodide uptake in SW1736 cells based on Sandell-Kolthoff reaction. For glucose uptake detection, ''GOD-PAP'' enzymatic colorimetric assay was applied to measure the direct glucose levels inside of the cells. Determination of NIS, GLUT1 and 3 mRNA expression in SW1736 cells was performed by qRT-PCR. Determination of NIS, GLUT1 and 3 protein levels in SW1736 cells was performed by western blotting. According to our results, Rutin inhibited the viability of SW1736 cells in a time- and dose-dependent manner. Quantitative Real-time RT-PCR analysis exposed that NIS mRNA levels were increased in Rutin treated group compared to the control group. Accordingly, western blot showed high expression of NIS protein and low expression of GLUT 1 and 3 in Rutin treated SW1736 cell line. Rutin increased iodide uptake and decreased glucose uptake in thyroid cancer cell line SW1736 compared to control group. Multiple mechanisms point to Rutin's role as a major stimulator of iodide uptake and inhibitor of glucose uptake, including effects at the mRNA and protein levels for both NIS and GLUTs, respectively. Here in, we described the flip-flop phenomenon as a possible therapeutic target for ATC. Moreover, Rutin is first documented here as a NIS expression inducer capable of restoring cell differentiation in SW1736 cell line. It also be concluded that GLUTs as metabolic targets can be blocked specifically by Rutin for thyroid cancer prevention and treatment.

Abstract PO3-08-07: Licochalcone A as a risk reducing agent against luminal and non-luminal breast cancers

Abstract Background: Breast cancer risk reducing drugs with proven efficacy have adverse side effects, significantly minimizing their uptake and impact. Further, they do not prevent ER- breast cancer. Effective alternative strategies with lower toxicity are needed. Previously, we have shown that licochalcone A (LicA) suppresses aromatase expression and activity, enhances the activity of detoxifying enzymes, and reduces estrogen genotoxic metabolism in cell lines and animal models. These data led us to hypothesize that LicA creates a tumor preventive environment in the breast by reprogramming metabolism and antioxidant/anti-inflammatory responses in the breast leading to decreased proliferation and tumor suppression. We now report on the breast tumor preventive effects of LicA in xenograft models, its oral bioavailability, and its biologic effects on human breast microstructures from women at increased risk of breast cancer. Methods: We prepared microstructures from the fresh tissue of contralateral unaffected mastectomy specimens of 6 postmenopausal women with incident unilateral breast cancer. After exposing them to DMSO (control) or LicA (5 µM), we performed total RNA sequencing. Differentially expressed genes were identified and analyzed by gene ontology and pathway membership. The RNA-seq data was also utilized to conduct metabolism flux analysis. Combined enrichment scores > 4 and FDR < 0.05 was considered significant. The NanoString metabolism panel was employed in 6 additional subjects. We performed live cell imaging to monitor proliferation of pre-malignant DCIS.COM, DCIS.COM/ER+ PR+; and malignant MDA-MB-231 (ER- PR-), MCF-7 (ER+ PR+), MCF-7aro, and BRCA1 defective HCC-1937, and HCC3153 cells. Xenograft models of MCF-7aro and MDA-MB-231 tumors were established in female nude mice and the animals treated for 28 days with vehicle or LicA (80 mg/kg.day, s.c.). We measured the rate of tumor growth. We also conducted a PK/PD study with oral LicA (100 mg/kg) in intact BALB/c female mice. Results: We observed significant (FDR < 0.05) upregulation of antioxidant genes (up to 8-fold), consistent with upregulation of NRF2 and the thioredoxin system, the major regulators of antioxidant pathways. This was accompanied by significant downregulation of RELA- and NF-kB1-dependent inflammatory pathways. In addition, we observed decreased expression of PI3K-AKT genes and the pro-adipogenic transcription factors SREBF1 and SREBF2, which may explain the downregulation (4 to 32-fold) of cholesterol biosynthesis and transport, and lipid metabolism genes. Metabolism studies confirmed these data and demonstrated a robust increase in the pentose phosphate shunt and NAD(P)H generation without enhancing ribose 5 phosphate formation, suggesting an antioxidant and anti-proliferative environment. LicA also suppressed proliferation of pre-malignant and malignant cells, with sustained effects on aggressive cells at doses < 10 µM. LicA significantly reduced tumor growth in luminal (P = 0.008) and triple negative (P = 0.001) in vivo models (unpaired t-test with Welch’s correction for unequal variances). Promising serum and breast bioavailability, equivalent to low micromolar concentrations sufficient to show efficacy was demonstrated as well. Conclusion: Our data suggest that LicA is a good candidate for breast cancer prevention in both ER+ and ER- breast cancers through reprogramming metabolism and antioxidant pathways leading to decreased proliferation. We will study LicA in intraductal models of ER+ and ER- precancer lesions in immunocompetent mice and will monitor their progression to invasive breast cancer to further establish its preventive efficacy. Citation Format: Atieh Hajirahimkhan, Elizabeth Bartom, Sriram Chandrasekaran, Susan Clare, Seema Khan. Licochalcone A as a risk reducing agent against luminal and non-luminal breast cancers [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 PO3-08-07.

Abstract PO5-08-06: Metabolic shift to serine pathway induced by lipids confers oncogenic properties in non-transformed breast cells

Abstract Introduction. Oncogenic factors that are local/in-breast are of great interest as they may be more specifically targetable for breast cancer prevention than systemic factors. We have identified a lipid metabolism gene signature that is enriched in breast tissue at risk for estrogen negative breast cancer (ER- BC). Utilizing the medium chain fatty acid Octanoic acid (OA) to probe lipid metabolism in non-transformed breast epithelial cells, we observed increased flux through several metabolic reactions and altered histone methylation with consequent changes in gene expression (e.g. neural genes). Neuronal signaling and regulatory circuits are observed in cancer cells of multiple origins, not just ones with ontological relationships to neurons. We hypothesize that the first and rate limiting step in the de novo serine pathway, which is catalyzed by Phosphoglycerate Dehydrogenase (PHGDH) is key to these observations. In the forward direction, PHGDH participates in the serine, one-carbon, glycine (SOG) and methionine pathways that produce the methyl donor S-adenosylmethionine (SAM) and in the reverse direction produces the oncometabolite 2-Hydroxyglycerate (2-HG). Methods. Non-transformed MCF-10A cells exposed to OA were utilized for U13C-glucose tracing. SAM and 2-HG concentrations following treatment with OA ± PHGDH inhibitor were measured by liquid chromatography. CUT&RUN for H3K4me3 was performed and genes affected by OA (PMID: 28263391) were compared with OA-responsive peaks. Single cell RNA-sequencing was carried out using breast microstructures derived from reduction mammoplasty tissue exposed to vehicle or OA. Microstructures were dissociated into single cells and sequenced using the 10x Genomics platform. The digital expression matrix file containing UMIs were analyzed with Seurat. Alkaline comet assay was performed to detect DNA breaks. Results. U13C-glucose tracing in presence of OA revealed that one-carbon-THF was redirected to the methionine cycle increasing flux to methylation. Concentrations of SAM and 2-HG increased after 15- and 30-min OA exposure, respectively; PHGDH inhibitor blocked these increases. H3K4me3 CUT&RUN revealed 661 differential peaks (FDR < 0.05) comparing OA to control. 73% of H3K4me3 OA-associated peaks were in regulatory regions of OA-induced genes (FDR < 0.01), these genes are involved in neural pathways, EMT and ER- BC. Motif analysis revealed an overrepresentation of binding sites for transcription factors ATF3/4 (p < 0.05), which are regulators of the serine pathway. Single cell RNA-sequencing revealed OA not only affected the distribution of cell subpopulations but also modulated the expression of many genes within each subcluster. The percentage of luminal progenitor subcluster 3 increased upon OA from less than 1% to about 13%. Within basal subcluster 3, OA drives the expression of ATF3, along with two of the enzymes in the de novo serine pathway: PHGDH and PSAT1. Alkaline comet assay showed DNA breaks in OA- and control 2-HG- treated cells. Conclusions. Metabolism of OA in preference to glucose and glutamine results in a metabolic shift toward the serine pathway increasing the production of SAM and 2-HG, with implications for oncogenesis: 1. SAM production results in epigenetic fostered plasticity leading to reprogramming/selecting cells that express genes consistent with a neural/neural crest-like state. These co-opted neuronal regulatory mechanisms can make critical contributions to the acquired functional capabilities that drive cancer development. 2. 2-HG exposure results in appearance of DNA breaks, which are likely consequent to the inhibition of the alpha-ketoglutarate-dependent dioxygenases KDM 4A/B by 2-HG. Their catalytic activity is required for homologous recombination repair; inhibition results in metabolic “BRCAness”. Citation Format: Mariana Bustamante Eduardo, Gannon Cottone, Shiyu Liu, Maria Paula Zappia, Elizaveta V. Benevolenskaya, Abul Bashar Mir Md. Khademul Islam, Maxim V. Frolov, Seema Khan, Susan Clare. Metabolic shift to serine pathway induced by lipids confers oncogenic properties in non-transformed breast cells [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 PO5-08-06.