Cohort Of Breast Cancer Patients Research Articles

Quantitative estimates of the regulatory influence of long non-coding RNAs on global gene expression variation using TCGA breast cancer transcriptomic data.

Long non-coding RNAs (lncRNAs) have received attention in recent years for their regulatory roles in diverse biological contexts including cancer, yet large gaps remain in our understanding of their mechanisms and global maps of their targets. In this work, we investigated a basic unanswered question of lncRNA systems biology: to what extent can gene expression variation across individuals be attributed to lncRNA-driven regulation? To answer this, we analyzed RNA-seq data from a cohort of breast cancer patients, explaining each gene's expression variation using a small set of automatically selected lncRNA regulators. A key aspect of this analysis is that it accounts for confounding effects of transcription factors (TFs) as common regulators of a lncRNA-mRNA pair, to enrich the explained gene expression for lncRNA-mediated regulation. We found that for 16% of analyzed genes, lncRNAs can explain more than 20% of expression variation. We observed 25-50% of the putative regulator lncRNAs to be in 'cis' to, i.e., overlapping or located proximally to the target gene. This led us to quantify the global regulatory impact of such cis-located lncRNAs, which was found to be substantially greater than that of trans-located lncRNAs. Additionally, by including statistical interaction terms involving lncRNA-protein pairs as predictors in our regression models, we identified cases where a lncRNA's regulatory effect depends on the presence of a TF or RNA-binding protein. Finally, we created a high-confidence lncRNA-gene regulatory network whose edges are supported by co-expression as well as a plausible mechanism such as cis-action, protein scaffolding or competing endogenous RNAs. Our work is a first attempt to quantify the extent of gene expression control exerted globally by lncRNAs, especially those located proximally to their regulatory targets, in a specific biological (breast cancer) context. It also marks a first step towards systematic reconstruction of lncRNA regulatory networks, going beyond the current paradigm of co-expression networks, and motivates future analyses assessing the generalizability of our findings to additional biological contexts.

PRE-ISPY phase I/Ib oncology platform program (PRE-I-SPY-P1).

e12641 Background: Many promising agents or combinations regimens relevant to breast cancer lack sufficient clinical information for use in the neoadjuvant setting. To enable acceleration of drug development by reducing time and cost of clinical trial planning and conduct, the Phase I initiative PRE-ISPY Program was created. Methods: The PRE-ISPY Program is built within the I-SPY network, with the overall aim to streamline the regulatory pathway and the processes of trial design, contracting, activation, enrollment, execution, data gathering and analysis, as well as reporting of new therapeutic agents or combinations of relevance to breast cancer. Results: The PRE-ISPY trial is an open-label platform phase IB study designed to evaluate compelling single agent or combination regimens with the overall goal of moving promising drug regimens into I-SPY2 Trial and/or into other oncology-based trials in a timely manner. Graduation of a PRE-ISPY regimen to I-SPY2 is not mandatory. The primary objectives in each study Arm are to determine safety and to obtain preliminary efficacy data of the new regimen in patients with metastatic cancer, including a cohort of breast cancer patients. Each Arm may contain a Part 1 (dose finding) and a Part 2 (dose expansion). The new treatment can be tested also in patients with other solid malignancies than breast cancer, in which the treatment may be applicable, as specified in the design of the Arm. A breast cancer specific cohort is required in Part 2. Candidate treatment regimens are selected with advice from the I-SPY2 Agent Selection Working Group. The PRE-ISPY/Phase IB trial has multiple ongoing drug regimen Arms subsequently added as new protocol appendices through amendments to a Master protocol. There is no randomization; participants are enrolled, and treatment selected according to the relevance of therapy to their disease. Prospective companion biomarkers are evaluated. The current arms under study are PRE1: ALX-148 combined with trastuzumab deruxtecan; PRE2: tucatinib combined with zanidatamab; and PRE3: vidutolimod combined with cemiplimab. Selected agents or therapeutic combinations are tested through this protocol in the I-SPY Network Centers that participate in the PRE-ISPY Program. Toxicities are graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE). Clinical responses are evaluated based on RECIST v1.1 criteria. Conclusions: Once safety is established, promising regimens can be rapidly transitioned to I-SPY 2.2 or other phase 2/3 trials. The first patient was enrolled on 2/1/2023. Clinical trial information: NCT05868226 .

Clinical features and outcomes of patients with breast cancer with leptomeningeal carcinomatosis.

e13162 Background: Leptomeningeal carcinomatosis (LMC) is a rare, but deadly complication in breast cancer, with prior studies showing median overall survival (OS) of 15 weeks. There is a paucity of data on histologic and receptor subtype-specific survival, and there is no standard of care currently for treatment of LMC in breast cancer. We reviewed the outcomes of a contemporary cohort of breast cancer patients (pts) with LMC. Methods: This is a single-institution retrospective analysis of 38 female breast cancer pts diagnosed with LMC between 2016-2023, based on radiographic features and/or positive cerebrospinal fluid (CSF) cytology or CSF circulating tumor cells (CTCs). Patients consented to share information with a research biorepository, and we conducted a chart review of their clinical features and OS with LMC. Results: 25 pts (65.8%) had invasive ductal carcinoma (IDC), 7 pts (18.4%) had invasive lobular carcinoma (ILC), 4 (10.5%) had metaplastic carcinoma, and 2 (5.3%) had mixed IDC/ILC. 22 pts (57.9%) had triple-negative breast cancer (TNBC), 12 (31.6%) had estrogen receptor positive (ER+)/human epidermal growth factor receptor 2 negative (HER2-), and 4 (10.5%) had HER2+ disease. Median age at LMC diagnosis was 50 years. Median time between Stage IV and LMC diagnosis was 11 months. Pts received a median of 2 lines of systemic therapy for metastatic disease prior to LMC diagnosis. 11 pts (28.9%) had parenchymal brain metastasis prior to LMC diagnosis. 32 pts (84.2%) had signs of LMC on Magnetic Resonance Imaging of the brain and/or spine at diagnosis. 25 pts underwent CSF cytology and 13 pts underwent CSF CTC evaluation at LMC diagnosis; 14/25 pts (56%) had positive CSF cytology and 10/13 pts (76.9%) had detectable CSF CTCs. 21 pts (55.3%) underwent whole-brain radiotherapy, and 2 pts (5.3%) received proton craniospinal irradiation. 21 pts (55.3%) received IT therapy. 27 pts (71.1%) received at least 1 line of systemic therapy post-LMC diagnosis. Median OS between LMC diagnosis and death or last oncology follow up for the entire cohort was 5 months (range 0-57 months, 95% CI 3.0-8.0). There was a significant difference in median OS with LMC by receptor subtype: TNBC 3.5 months, ER+/HER2- 8 months, and HER2+ 23 months (p=0.0047). Two HER2+ pts survived ≥ 3 years post-LMC diagnosis with anti-HER2 antibody-drug conjugates and tyrosine kinase inhibitors +/- stereotactic radiosurgery (SRS) to parenchymal brain metastases. Amongst 9 pts with ER+/HER2-low disease, longer survival with LMC (≥ 16 months) was observed with trastuzumab deruxtecan, IT topotecan +/- IT trastuzumab, and SRS to parenchymal brain metastases. Conclusions: This study highlights heterogeneity in outcomes amongst breast cancer pts with LMC by receptor subtype, as well as improvement in outcomes for selected pts treated with novel therapeutics and a multidisciplinary approach. Larger prospective studies are needed to inform treatment paradigms for LMC.

Predicting peripheral neuropathy following neoadjuvant therapy in patients with breast cancer.

e12639 Background: Administration of neoadjuvant chemotherapy (NACT) or radiation is widely used to improve outcomes in patients with breast cancer. This strategy has demonstrated remarkable efficacy in reducing tumor burden and increasing the likelihood of breast-conserving surgery. However, neoadjuvant therapy can induce peripheral neuropathy, a condition characterized by nerve damage or dysfunction in the extremities that often manifests as pain, tingling, or weakness in the hands and feet. The exact mechanism remains unclear, although likely involves the cumulative toxic effects of therapy on peripheral nerves. Treatment-induced neuropathy poses a substantial unaddressed challenge that can significantly impact the patient’s quality of life. Therefore, predicting and ameliorating neuropathy are crucial aspects of comprehensive cancer care. Methods: We used an AI spatial biology platform to create and assess 3D depictions of a cohort of breast cancer patients based on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) data. Clinical, pathological, and radiological data were collected on 74 patients from Yale New Haven Hospital. Due to missing regimen data, the final dataset included 71 patients, with mean age 51.1 (14.5) years. An AI-based segmentation algorithm was successfully employed on 63 patients, of whom 13 had neuropathy following NACT. Vascular and microvascular (MV/V) kinetic parameters were computed for each, and radiomic features were extracted. Machine learning models were developed for clinical features, MV/V features, and the combined set of features. All models were tested with leave-one-out cross-validation. Results: The clinical model did not forecast neuropathy in any patient, indicating poor predictive ability. The MV/V model performed the best, with accuracy, precision, recall, and AUROC of 0.84, 1.0, 0.18, and 0.69, respectively. The combined model showed intermediate performance, with accuracy, precision, recall, and AUROC of 0.81, 0.5, 0.18, and 0.58, respectively. The patient population limits broad conclusions, but suggests features that are aligned with increased occurrence of neuropathy. In particular, vascular features that describe transfer of nutrients between tissues, as well as the density of blood vessels within and around the tumor, are prominent within both the MV/V and combined models. Conclusions: These results indicate that features associated with the degree of proximal and intratumoral vascularity may be predictive of peripheral neuropathy in breast cancer patients. Moreover, these features can be extracted from standard-of-care DCE-MRI data. Expansion of this vascular analysis could enable physicians to better plan and manage care for patients by tailoring treatment dose. [Table: see text]

Pathological complete response rate to anthracycline versus non−anthracycline based chemotherapy regimens in localized and regional HER2 neu positive breast cancer.

e12632 Background: Debate over the need of anthracycline as part of neoadjuvant chemotherapy in HER2-neu early breast cancer was addressed in many trials with results favoring similar outcomes with or without anthracycline. This was not adopted fully in Saudi Arabia because of concern regarding ethnic differences in response to treatment. We conducted this retrospective analysis to evaluate if there is any difference in pathological complete response rate (PCR) in patients with early HER2-neu positive breast cancer depending on neoadjuvant chemotherapy regimen. Methods: Patients with HER2-neu positive early breast cancer who were treated with neoadjuvant chemotherapy at Johns Hopkins Aramco Healthcare (JHAH) facility between the year 2018 and 2022 were all evaluated for pathological subtype, HER2-neu status and type of neoadjuvant chemotherapy administered. Pathological response status was evaluated in all patients and PCR was measured to see if there was any difference depending on the use of anthracycline (AC) or non-anthracycline (non-AC) based chemotherapy regimen. Patient demographics, tumor characteristics, clinical stage, treatments and outcomes were collected via JHAH’s oncology registry. Categorical variables are reported as frequencies and percentages. The association between chemotherapy regimen AC vs non-AC based and PCR was analyzed using Fisher Exact Test. p-value <0.05 was considered statistically significant. Analyses were conducted using JMP version 15. Results: In this study 59 HER2-neu positive early breast cancer patients were identified. We examined their clinical characteristics and treatment outcomes. Median age was 57. The most prevalent histology was invasive carcinoma of no special type (79.66%), Estrogen receptor positivity was observed in 72.88% of patients, while progesterone receptor positivity was seen in 62.71% of cases. Majority of patients were alive (96.61%) at the time of data collection. There was no significant difference in clinical stage in both groups. The association between chemotherapy type and pathological response was assessed. Among patients receiving AC chemotherapy (n=29), 55.17% achieved PCR, while for patients receiving Non-AC chemotherapy (n=30), the PCR rate was 50%. However, this difference was not statistically significant (p-value = 0.8). Conclusions: In our cohort of HER-neu positive early breast cancer patients who received neoadjuvant therapy there seems to be no significant difference in PCR with AC or Non-AC based chemotherapy regimens. This is concordant with the international trends.

Predicting epirubicin response in Danish patients with breast cancer.

539 Background: Anthracyclines are highly effective chemotherapy drugs. However, they are toxic and feared for their cardiotoxicity. There is a need for improved personalized prediction of treatment benefit. For example, state-of-the-art guidelines (NCCN Guidelines Version 1.2024 and meta-analysis PMID: 37061269) mark anthracyclines as optional adjuvant treatment of estrogen receptor (ER) positive, HER2 negative early high-risk breast cancer. A biomarker to predict whether a patient will benefit from anthracycline treatment could potentially lead to increased cure rate and overall reduced toxicity. However, no such test exists. Here we introduce a clinically validated, predictive test based on clinical tumor transcriptome data and the cell line panel NCI60 that can forecast epirubicin response in breast cancer patients with high accuracy. Methods: Microarray gene expression levels and growth inhibition levels (GI50) from the NCI60 cell line panel were acquired from NCBI to build a prediction algorithm. A tumor-specific variance-based filter based on >6.000 patient tumors was applied to select the most relevant genes. AUC (Area Under Curve) was used to evaluate the performance of numerous configurations and combinations of parameters that led to different gene-signature sets. Response scores based on the gene expression level of all genes in each signature were generated for each sample in a published cohort (PMID: 23340299) and a final signature with 141 genes was the best-performing signature (Progressive Disease versus Response AUC 0.81 and ANOVA-test p-value < 0.01). The model was validated on a cohort of Danish breast cancer patients treated with epirubicin in the metastatic setting (n=153), with time-to-progression (TTP) as endpoint (PMID: 31654283, PMID: 30099635). Finally, we used an established method (PMID: 30289602) to test if the gene signature was correlated between microarray- and RNA sequencing-based datasets. Results: The hazard ratio (HR) for the best-performing signature was 0.31 when comparing patients with a difference of at least 50 in response score (two-sided p-value = 0.012, 95% confidence interval 0.12-0.77, endpoint TTP, continuous scoring). This was consistent in a multivariate model including ER and HER2. Using the data and method provided by Pedersen et al (PMID: 30289602), we also saw a high correlation between matching microarray and RNA sequencing datasets for the genes in our model (mean Pearson’s r = 0.87). Conclusions: Here is presented a development and clinical validation of an accurate epirubicin response signature for breast cancer patients. The expression of the genes in the signature is highly correlated between microarray- and RNA sequencing data. Moving forward, we will seek to validate the model independently on RNA sequencing data. Our aim is that these models will be accepted for prospective clinical tests at local hospitals in Denmark in early 2025.

Real-world duration of interruptions in imaging and endocrine therapy (ET) after pregnancy in early-stage estrogen receptor (ER) positive breast cancer (BC).

11157 Background: Pre-menopausal women with early-stage ER-positive BC often desire the option for future fertility. The POSITIVE trial demonstrated that a pause in ET to conceive is safe. However, the real-world durations of these pauses, as well as how many patients resume ET, are unclear. Additionally, there are limited data about when and if women reestablish imaging surveillance after childbirth. Methods: We generated a cohort of BC patients with a pregnancy-related ICD diagnosis from the Oncoshare registry. This registry merges EMR and California Cancer Registry data for patients treated in the Stanford Health Care Alliance which includes an academic hospital, a community hospital, and a community practice network. Included patients had ≥1 pregnancy after a diagnosis of stage 0-3 ER-positive BC. Chart review confirmed pregnancy and was used to abstract treatment information. Data are presented as unadjusted percentages or medians with interquartile ranges (IQR). Among patients without bilateral mastectomies, we compared time from delivery to first imaging (MRI or mammogram) for those who breastfed vs not and those who restarted ET vs not using the Wilcoxon rank sum test. Results: Of the 317 charts reviewed, 71 were included. Most exclusions were due to no pregnancy (46%) or ER-negative disease (25%). Year of diagnosis ranged from 1994 to 2020, with the majority (79%) from 2010 to 2020. Median age at diagnosis was 33 years (IQR 30-35). The distribution of stages was 18% in situ disease, 51% stage 1, 17% stage 2, 14% stage 3. 23% (16/71) of women never started ET, with 14 attributing this decision to desiring pregnancy. Among the 55 women who started ET, 75% received tamoxifen without ovarian suppression (OS). After 2015, use of OS became more prevalent (45% of ET), coinciding with the emergence of the SOFT/TEXT data. The median time from ET onset to a pause for pregnancy was 32 months (IQR 22-53), and the median ET pause to delivery was 23 months (IQR 14-48). We recorded 90 pregnancies resulting in 85 live births. After delivery of their first child, the median follow-up was 3.8 years (IQR 2.0-6.8). 40% of patients never restarted ET. Those who did restart did so at a median of 5 months (IQR 3-11) post-delivery. Imaging surveillance resumed for 42% (27/64) at a median of 6 months post-delivery [IQR 3-11]. Time from delivery to imaging was similar between those who restarted ET and those who did not (p=0.91), and between those who breastfeed and those who did not (p=0.42). Conclusions: These data support prior work showing that fertility concerns strongly influence adjuvant therapy choice in ER-positive BC. The ET resumption rate after pregnancy was lower in our analysis compared to the POSITIVE trial (73% vs. 40%). Only 42% of women resumed surveillance imaging. This points to clear gaps between the clinical trial population and the real-world clinical setting.

A non-invasive preoperative prediction model for predicting axillary lymph node metastasis in breast cancer based on a machine learning approach: combining ultrasonographic parameters and breast gamma specific imaging features.

The most common route of breast cancer metastasis is through the mammary lymphatic network. An accurate assessment of the axillary lymph node (ALN) burden before surgery can avoid unnecessary axillary surgery, consequently preventing surgical complications. In this study, we aimed to develop a non-invasive prediction model incorporating breast specific gamma image (BSGI) features and ultrasonographic parameters to assess axillary lymph node status. Cohorts of breast cancer patients who underwent surgery between 2012 and 2021 were created (The training set included 1104 ultrasound images and 940 BSGI images from 235 patients, the test set included 568 ultrasound images and 296 BSGI images from 99 patients) for the development of the prediction model. six machine learning (ML) methods and recursive feature elimination were trained in the training set to create a strong prediction model. Based on the best-performing model, we created an online calculator that can make a linear predictor in patients easily accessible to clinicians. The receiver operating characteristic (ROC) and calibration curve are used to verify the model performance respectively and evaluate the clinical effectiveness of the model. Six ultrasonographic parameters (transverse diameter of tumour, longitudinal diameter of tumour, lymphatic echogenicity, transverse diameter of lymph nodes, longitudinal diameter of lymph nodes, lymphatic color Doppler flow imaging grade) and one BSGI features (axillary mass status) were selected based on the best-performing model. In the test set, the support vector machines' model showed the best predictive ability (AUC = 0.794, sensitivity = 0.641, specificity = 0.8, PPV = 0.676, NPV = 0.774 and accuracy = 0.737). An online calculator was established for clinicians to predict patients' risk of ALN metastasis ( https://wuqian.shinyapps.io/shinybsgi/ ). The result in ROC showed the model could benefit from incorporating BSGI feature. This study developed a non-invasive prediction model that incorporates variables using ML method and serves to clinically predict ALN metastasis and help in selection of the appropriate treatment option.

Abstract PO5-02-14: Clinical-pathological determinant factors to choose between four or six cycles of adjuvant chemotherapy with docetaxel/cyclophosphamide (TC) in a retrospective real-world cohort of HER2-negative breast cancer patients

Abstract Introduction: The long-term severe adverse events associated with anthracyclines, including irreversible cardiotoxicity, myelodysplastic syndromes, and therapy-related leukemias, led researchers to question the risk-benefit of anthracycline-based chemotherapy regimens, especially for patients without axillary lymph node involvement, leading to an increasing trend to omit anthracyclines in adjuvant treatment. Docetaxel plus cyclophosphamide (TC) has replaced doxorubicin plus cyclophosphamide (AC) for lower-risk patients that need adjuvant chemotherapy. However, the optimal number of cycles of adjuvant in patients with node-positive or node-negative breast cancer is currently unknown. Methods: We performed a retrospective cohort study of patients with HER2-negative breast cancer, stage I to III, that received adjuvant docetaxel and cyclophosphamide (TC) for four or six cycles, treated from January 2010 to December 2021. Patients were included from four cancer institutions, both private and public, located in the South, Southeast, and Northeast of Brazil. Objectives: To investigate the clinical-pathological characteristics and survival of earlystage HER2-negative breast cancer patients who received four (TC4) or six cycles (TC6) of adjuvant docetaxel and cyclophosphamide (TC). Results: We collected data from six hundred and ninety-eight patients, 98.7% were female with an average age of 52 years, 51.9% were postmenopausal, 14.6% BRCA gene mutation, 66% had some comorbidity, and only 8.4% were not candidates for anthracyclines. Two hundred and twenty-five patients had public and 473 private health insurance. About 13.2% of the patients were hormone receptor negative (HR-) and 86.8% hormone receptor positive (HR+), 57.4% breast-conserving surgery and 77.7% sentinel lymph node (SL). Five hundred sixty-four (80.8%) patients received TC4 and 134 (19.2%) TC6. We observed that patients who received TC 6 had unfavorable prognostic factors such as: (TC4 vs TC6) previous breast cancer (8.7% vs 16.3%) (p=0.002), invasive ductal carcinoma (IDC) (73.4 vs 86.7%) (p=0.009), histological grade 3 (HG3) (34.9 vs 42.9%) (p= 0,085) conservative surgery (59.4% vs 53%) (p=0144), SL (80.9% vs 62.2%) (p =0.001), Lymph node positive (15% vs 42.3%) (p=0.001), pathological stage II (37.5% vs 50%) (p=0.001).Treatment completion rates were 96.5% and 84.3% for TC4 and TC6, respectively (p=0,02). The incidence of grade 3 or higher toxicity with TC6 (14% vs 21.1%; p= 0,043). Febrile neutropenia was observed in 6.7% of both groups. Grade 3 or higher neuropathy was most common with TC6 (2.2% vs 10.3%; p=0,163). Permanent treatment discontinuation was more frequent in the TC6 group (3.4% vs. 9.8%; p=0,004), as well as late toxicity (3.4% vs. 9.2%; p=0,004). Ninety-four percent of the patients completed the proposed cycles of chemotherapy, 72% received adjuvant radiotherapy and 85.4% received adjuvant hormone therapy, with 42% of these receiving an aromatase inhibitor for 5 years. The median follow-up of the entire cohort was 61 months. There was no difference in the 5-year DFS (77.5% vs. 64.7%; p=0.159) or the 5-year OS (89.5% vs. 70.5%; p= 0,06) between patients treated with TC4 and TC6. Conclusion: TC6 was commonly used for patients with unfavorable prognostic factors as history of previous breast cancer, (IDC), HG III, lymph node positive and stage II. Patients who received TC6 had less chance of completing the treatment and more severe toxicity, especially late peripheral neuropathy. There was no difference in DFS or OS. Citation Format: Mila Kraychete, Marcelle Cesca, Guilherme Almeida, Leonardo Santana, Luciana Leite, Solange M. Sanches, Vladmir Cordeiro de Lima, Rafaela Pirolli, Rafael Manea, Felipe Kaneta, Jean Coutinho, Lucas Vian, Waires Zeviani, Marcio Reis, Luciana Landeiro, Clarissa Mathias, Geila Nunez, Tamara Santana, Monique Tavares. Clinical-pathological determinant factors to choose between four or six cycles of adjuvant chemotherapy with docetaxel/cyclophosphamide (TC) in a retrospective real-world cohort of HER2-negative breast cancer patients [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 PO5-02-14.

Abstract PO5-25-03: Immune cell infiltrate profiles in primary Triple Negative Breast Cancer and co-relation with treatment response and survival outcomes

Abstract Introduction Tumor microenvironment (TME) in breast cancer is a heterogeneous landscape with multiple cell types, each modulating the tumor progression and the disease prognosis. These cell types include lymphocytes, RBCs, stromal cells, macrophages, cancer-associated fibroblasts (CAFs), and cancer stem cells. Each cell type in the TME influences tumor progression and clinical outcomes for patients in a good or bad way, depending on the interaction with tumor cells. Tumor-infiltrating lymphocytes (TILs) are shown to be prognostic for therapy response in many cancers in the western cohorts. Our recent study showed that a higher proportion of Indian TNBC patients had intra-tumoral TILs compared to Western cohorts, and these are predictive of better response to NACT and longer disease-free survival in patients, making it a distinct finding from Western reports. In the follow-up study, we are characterizing infiltrating immune cell subtypes and their comparative association with treatment response in TNBC patients. Results from preliminary analysis and comparative analysis between responders and non-responders will be presented here. We speculate that the pro- and anti-tumorigenic immune cell population and its spatial information would help us understand TME and its precise role in response to therapy. Methods A retrospective cohort of breast cancer patients from a single one-surgeon breast cancer clinic with a uniform treatment strategy was evaluated for this study. FFPE primary tissue samples with variable TILs scores (moderate to high), taken from patients who showed complete response to the NACT treatment (n=6) and non-responding group (n=8) determined by H&E stained slides from our cohort, were further stained for immune cells (Pan-B cell, Pan-T cells, Pan-macrophages) and T cells (CD4; Helper T cell marker, CD8; Cytotoxic T cell marker), FOXP; Regularly CD4+ cell marker) and PanCK (Pan-tumor marker) and counterstained with DAPI for multiplex imaging. Multispectral images for these slides were obtained using the Leica Aperio Versa system. Parameters such as individual cell types of identification and scoring, spatial proximity to tumor cells, and individual cell types will be determined by HALO software using the High plex module. Results A total of 14 TNBC samples were stained for the T-cell subtypes panel and Immune cell subtype s panel to determine the TIME. DAPI stain was used for nuclear counting based the parameters such as threshold intensity, nuclear size, roundness, and aggressiveness. The cytoplasmic size was selected as 2um beyond the outside nuclear boundary. Using Halo-Indica software, around 50000-300000 cells/tissue were evaluated across all samples from mIF whole slide scans of biopsy samples. Cell count was validated by cross-checking individual ROIs and manual cell count using Fiji. A Highplex module was used to identify individual signal positivity for each marker based on threshold intensity and cell completeness percent. Preliminary data showed a higher proportion of CD8+ cells and macrophages population are spatially closer to the tumor cells in Responders compared to non-responders. Conclusion Immune profiles are distinct among responding and non-responding patients in the Indian TNBC cohort. The association of these profiles with long-term survival in patients and various clinical and pathological parameters will help us determine the clinical relevance of these profiles and identify distinct immune subgroups as prognostic in Indian TNBCs. Citation Format: Pooja Vaid, Devaki Kelkar, LS Shashidhara, C B Koppiker, Madhura Kulkarni. Immune cell infiltrate profiles in primary Triple Negative Breast Cancer and co-relation with treatment response and survival outcomes [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 PO5-25-03.

Abstract PO5-22-02: Evaluation of a surface-guided and tattoo-less approach to setup for whole breast radiotherapy

Abstract Background: In preparation for adjuvant breast radiation therapy (RT), several small but permanent skin tattoo marks are often placed to assist with surface alignment for treatment setup and delivery. With advancements in surface-guided technologies, it may be possible to achieve setup accuracy with a “tattoo-less” approach, which can improve cosmetic and quality of life outcomes. This study evaluates the feasibility, accuracy, and potential dosimetric implications of a tattoo-less setup technique. Method: A retrospective analysis of 10 patients diagnosed with right-sided breast cancer who received adjuvant whole breast RT using a tattoo-less approach were included in this study. All patients received an initial whole breast dose of 42.56 Gray (Gy) in 16 daily fractions using a tangential three-dimensional conformal planning technique. This was followed by a 10Gy boost to the lumpectomy site delivered in 4 daily fractions. Daily setup for whole breast treatment was performed by aligning each patient to their individual reference breast surface generated from the planning computed tomography (CT) images via the Vision RT system. Bony landmarks were then verified via daily kV imaging, and translational shifts were recorded for each fraction. The kV imaging was performed to confirm the treatment positioning since the tattoo-less approach was new to the department. For 5 patients, dosimetric differences between initial surface alignment and shifts performed based on bony landmarks were evaluated by recalculating the original clinical plan with a new isocenter position using kV image shifts for each of their 16 treatment fractions. A plan sum of the 16 recalculated plans for each patient was used in further dosimetric analysis. Boost fractions were not included in this study, as setup was verified using surgical clips instead of bony anatomy. Results: Translational shifts for 158 fractions were reviewed as no kV imaging was performed for the other 2 fractions. The mean absolute kV imaging shift was 0.29 cm (CI (95%): 0.25, 0.32; range: 0 to 1.25) in the vertical axis, 0.28 cm (0.23, 0.32; 0 to 1.27) in the longitudinal axis, and 0.24 cm (0.20, 0.28; 0 to 1.98) in the lateral axis. Clinical plans for 5 patients were evaluated with a mean absolute kV shift of 0.27 cm (range: 0.15 to 0.39) in the vertical, 0.32 cm (0.13 to 0.77) in the longitudinal, and 0.29 cm (0.18 to 0.38) in the lateral directions. Dosimetric analysis revealed a slight increase in mean heart dose from the original clinical plan, with an average difference of 4.12 cGy (range: 0.7 to 10.5 cGy). The maximum increase in V20Gy of the ipsilateral lung was 2.7%. Less than 1% of change was observed in the maximum plan dose, as well as in the V95% coverage, expect for one patient, whose V95% was decreased from 99.6% to 94.6%. This difference was caused by a large longitudinal shift which could be attributed to possible patient movement. Conclusions: These findings demonstrate the feasibility and accuracy of a tattoo-less treatment approach in a small cohort of breast cancer patients receiving whole breast RT. Further investigation with larger cohorts is warranted. Citation Format: Xinxin Zhang, Swati Mamidanna, Yin Zhang, Xiao Wang, Ning Yue, Shicha Kumar, Lindsay Potdevin, Maria Kowzun, Mridula George, Lara Hathout, Bruce Haffty, Nisha Ohri. Evaluation of a surface-guided and tattoo-less approach to setup for whole breast radiotherapy [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 PO5-22-02.

Abstract PO5-10-07: Risk factors associated with secondary cancers in AYA patients with breast cancer. A SEER database study

Abstract Background Adolescents and young adults (AYA) diagnosed with breast cancer face unique challenges and have distinct characteristics compared to older patients. While primary breast cancer remains a significant concern, the risk of developing secondary cancers in this population is also of great importance. This study aimed to identify these risk factors by analyzing a large cohort of AYA breast cancer patients using SEER (Surveillance Epidemiology and End Result) Database. Methods Patients were identified from SEER Research Data 17, from 2000 to 2019. Patients aged 18-39 years with breast cancer and at least 1 year of survival were identified. Secondary cancers were then identified and included any disease site. Patient demographic and clinical characteristics were summarized by secondary cancer status using Mann-Whitney U and Fisher’s exact tests. Overall survival from the initial breast cancer diagnosis was summarized by secondary cancer status using standard Kaplan-Meier methods, where the median and 3/5-year rates were estimated with 95% confidence intervals. Comparisons were made using the log-rank test. SAS v9.4 (Cary, NC) was used at a significance level of 0.05. Results A total of 47,912 AYA breast cancer patients were identified, of which 2,886 (6.0%) developed a secondary cancer at least 1 year after the initial breast cancer diagnosis. When comparing patients with and without secondary cancers, we observed significant differences with respect to age at initial breast cancer diagnosis, race, stage, nodal status, surgical procedure, ER status, PR status, Her2 status, and sub-type (Table 1). The analysis of overall survival showed that, from the time of breast cancer diagnosis, there was no statistically significant difference between patients with and without secondary cancers. However, this may be due to an immortal time bias. Breast was the most common site of secondary cancer (67%) followed by gynecological (7%), colorectal (3.7%), skin (3.4%) lung and hematologic (2.7%) Compared to other subtypes, TNBC patients were found to have much shorter time to secondary cancer development of 38 months compared to Her2+ and ER/PR+ (40 and 45 months respectively, P< 0.001). Black and Hispanic individuals were found to have higher rates (7.4% and 6.3%) and earlier development of secondary cancer (76 months and 74 months) as compared to whites and Asians (5.9% and 5%, 88 months and 81 months, P< 0.001 and P< 0.002 respectively). Conclusion This study identified several risk factors associated with the development of secondary cancers in AYA breast cancer patients such as age at initial breast cancer diagnosis, race, stage, nodal status, surgical procedure and sub-type. Higher rates and early development of secondary cancer were observed among TNBC subtype and Black and Hispanic races that calls for further investigation and tailored interventions to improve outcomes in specific patient populations. Table 1 showing significant differences in characteristics AYA breast cancer patients who developed secondary breast cancer compared to those who did not Citation Format: Sheeba Ba Aqeel, Alankrita Taneja, Shipra Gandhi. Risk factors associated with secondary cancers in AYA patients with breast cancer. A SEER database 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 PO5-10-07.

Abstract PO2-07-04: Applying the Alliance Trial Guidelines in Multi-focal Breast Disease Using an Artificial Intelligence Computational Platform: Economic Analysis and Cosmetic Sensitivity

Abstract Background: Traditionally, multi-focal breast cancer results in mastectomy. The Alliance Trial offers a paradigm shift in surgical options available for multi-focal breast cancer patients in the context of adjuvant chemotherapy. In the trial, patients with multi-focal disease (< 3 tumors) who underwent breast conservation surgery (BCS) were found to have similar outcomes to patients undergoing mastectomy. BCS for large volume tumors ( >30%) has been cited as having a high potential for cosmetic defect, and hence represents a typical upper limit for potential tissue removal in BCS. Here, we evaluated a patient cohort to better understand the economic impact of the Alliance trial and further categorize patients that would most benefit without suffering cosmetic impact. We employed a novel computational technology to quantify the ratio of tumor size to breast tissue volume. Methods: Using a publicly available, single site cohort (n=243, DUMC) of breast cancer patients that underwent mastectomy, we segmented the tumors using our TumorSight Viz software platform. This platform uses artificial intelligence to segment the tumor and surrounding tissues and allows for a volumetric and morphologic assessment in 3D space. We then applied relevant inclusion/exclusion criteria from the Alliance Trial to the cohort (Saha et al, 2018). In trial eligible patients, we used TumorSight Viz to create a convex hull (CH) around the multi-focal disease using dilations of 1 cm and 2 cm. The volume of the CH, corresponding to proposed surgical extirpation, and the overall breast volume (BV) were then computationally assessed in 3D. The ratio of CH to BV (CH:BV) was calculated and a cutoff of 30% (high potential for cosmetic deformity) was applied. A cost analysis was then carried out. We determined the aggregate per annum savings that could potentially be realized by transforming a subset of mastectomies to BCS by tabulating total costs of mastectomy+reconstruction vs. BCS+WBI (whole-breast irradiation), as well as adjusted for relative rates of adjuvant therapy (~80%) across the nationwide patient population. Results: We found that 19.3% of adjuvant mastectomy patients were eligible for BCS based on Alliance Trial criteria. Of those, 68% had tumor CH:BV < 30% when using a 1 cm dilation around the tumor. When using a 2 cm dilation, 56% had tumor CH:BV < 30%. Together, these results indicate that of all adjuvant mastectomy patients, an estimated 10.8-13.1% are eligible for BCS based on volumetric measures of cosmetically acceptable breast tissue removal. Our economic analysis of BCS vs. mastectomy revealed an estimated $28,500 cost savings for patients with private insurance, suggesting that both decreased costs and improved quality-of-life (QOL) can be mutually aligned. By assessing the nationwide number of patients receiving adjuvant therapy for breast cancer, alongside the percentage potentially eligible for BCS using the above cosmetic defect analysis, we estimate that BCS conversion from mastectomy offers to provide a net savings of $300-350 million annually. Conclusion: The Alliance Trial guidelines unveiled the potential option of BCS in ~20% of patients with multi-focal disease in our cohort, demonstrating considerable cost-savings. Computational tools can further differentiate individuals who may not be best candidates for BCS in this setting, ensuring high QOL and informed decision-making. Citation Format: John Pfeiffer, Matthew Biancalana, Dorys Lopez-Ramos, Bradley Feiger, Anuja Antony. Applying the Alliance Trial Guidelines in Multi-focal Breast Disease Using an Artificial Intelligence Computational Platform: Economic Analysis and Cosmetic Sensitivity [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 PO2-07-04.

Abstract PO4-09-02: Making a Case for Access to Genetic Testing in a Low Resource Country: A review of 313 Cases of MBC

Abstract Background Breast Cancer is the most common malignancy in Nigerian Women. It is responsible for the highest mortality amongst all malignant conditions. Breast cancer in Nigerian women typically presents at an earlier age and with a more aggressive tumour with triple negative molecular pattern in Nigerian women. These are usually some of the criteria for Genetic testing in the NCCN Guidelines. Due to resource challenges, Genetic testing is not readily available to Nigerian women We believe that if we can demonstrate that a high proportion of Nigerian women with breast cancer meet the criteria for Genetic Testing for Hereditary Breast and Ovarian Cancers, a case can be made for deploying resources towards Genetic Testing in this population of Women. Materials and Methods We collected prospective data about Nigerian Patients with Metastatic Breast Cancer as part of a UICC MBC Grant. We evaluated these patients for criteria for testing for breast cancer and present the result of our evaluation. Results Three hundred and Thirteen patients were recruited for this study. There were 2 male and 311 female. Twelve participants did not know their age, but 146 (40.3%) were younger than 45 years while 175 (55.9%) were older than 45 years. Twenty four (7.7%) had bilateral breast cancer while the 289 (92.3%) had unilateral breast cancer. One hundred and sixty two (54.8%) participants were triple negative, 124 of whom were 60 years or younger. In total, out of 313 participants, 202 (64.5%) patients were candidates for Genetic testing in a cohort of Metastatic Breast Cancer patients in Nigeria. Conclusion Various Indications for Genetic Testing in a cohort of Nigerian patients with breast cancer exists in more than 60% of patients. Considering the importance of PARP inhibitors in the management of breast cancer and implications for family members of these patients. It is important that cost appropriate genetic testing is made available to this group of breast cancer patients. Table. Risk Factors for Genetic Testing in Nigerian Patients Citation Format: Adewumi Alabi, AbdulRazzak Lawal, Tolulope Falowo, Olamijulo Fatiregun. Making a Case for Access to Genetic Testing in a Low Resource Country: A review of 313 Cases of MBC [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 PO4-09-02.

A Pilot Study to Show Longitudinal Trends in Health-Related Quality of Life (HRQOL) in a Cohort of Breast Cancer Patients Under Treatment at a Tertiary Healthcare Facility in Bhubaneswar, India.

Breast cancer incidence has overtaken that of cervical cancer among women in India according to the Globacon 2020 reports. Cancer management is also being streamlined at the Center and district levels, such that comprehensive integrated management is offered to cases to optimize the best results. In breast cancer, there are two modes of surgery namely Breast Conservation Surgery(BCS) and Modified Radical Mastectomy (MRM) now over 2 decades, with recommended Chemo radiation depending on the extent of the disease. HRQOL (Health-related Quality of Life) studies have been done in these groups of patients, due to their added relevance in terms of the loss of a vital organ like the breast. EORTC 30 and BR23 are standardized and detailed tools that have been seen to estimate QOL, keeping in mind a whole array of domains that are affected by the disease. To evaluate the "Body Image" and "Quality of life" (QOL) in operated breast cancer patients using BR -23 and EORTC - QLQ- questionnaire at 1month (after surgery) and then 3 to 4 months after surgery. This article attempts to draw a comparison among of EORTC30 and BR 23 scores calculated for 46 breast cancer patients operated during the pandemic time in one center and consenting to repeat the measures at pre-decided three time periods during the course of management. No significant differences are noted in the mean scores for EORTC 30 and BR23 for the two types of surgeries. Visit 1 scores for both modes of surgery are over 75 and by Visit 3 become less than 55 for EORTC. BR 23 (which measures the symptoms core to Breast cancer) at all 3 visits are between 45 to 55. Friedman's test shows that the scores are not significant for age groups, the number of living children, or lifestyle factors like alcohol or tobacco chewing, though quadratic graphs depict the distinct variations in the scores at the 3 times reinforcing the need for follow-up of mental health in these subjects at intervals. The study largely brings out a strong need for repeated follow-up and counseling at regular and short intervals, post-surgery in breast cancer patients. EORTC 30 and BR 23 tools are excellent to use to essay information on the mental health of patients with breast cancer.

A Pilot Study of Detecting RS920778 and RS1899663 Genetic Variants of HOTAIR in A Cohort of Sporadic Breast Cancer Patients in Sri Lanka

Background: Some functional single nucleotide polymorphisms (SNPs) on the HOTAIR gene are potent to elevate breast cancer risk where rs920778 and rs1899663 are associated with the expression and function of the HOTAIR gene, and these SNPs were detected in the current study. Methods: A cohort of nine sporadic cancer patients and five healthy controls were screened for selected HOTAIR variants using direct sequencing. Results: Among patients, seven were with TT genotype, and other 2 with CT genotype for rs920778 C>T while two healthy controls showed TT, another two were with CT, and the remaining with CC genotypes. Among the cohort, the rs1899663 variant was not found in any patients and healthy controls., Conclusion: In the study, the T allele of rs920778 was prominent among the sporadic breast cancer in the studied cohort while only a wild allele (T) of rs1899663 was more prominent in the patients and healthy controls.

Association between pathological characteristics and recurrence score by OncotypeDX in resected T1-3 and N0-1 breast cancer: a real-life experience of a North Hungarian regional center.

Introduction: The 21-gene analysis (OncotypeDX) is validated test for pT1-3, pN0-1 with hormone receptor (HR) positive and normal expression of human epidermal growth factor receptor-2 (HER2) breast cancer (BC) to determine the aggressiveness of the disease based on the calculation of Recurrence Score (RS). Methods: In this retrospective study the authors correlated pathological characteristics and Recurrence Score (RS) by traditional statistical methods and Observed Oriented Modeling (OOM) in a realistic cohort of BC patients. Results: OncotypeDX tests were performed in 94 tumour specimens of 90 BC patients. >83% of node-negative (pN0) and >72% of node-positive (pN1) cases could avoid chemotherapy. For pN0 cases, non-parametric correlation and tests demonstrated significant association in eight types of characteristics [progesterone receptor (PR) expression, Ki-67 value, Ki-67 group, PR group, grade, estrogen receptor (ER) expression, Nottingham Prognostic Index (NPI) and Clinical Risk]. For pN1 cases, parametric correlation and tests showed significant association in six characteristic types (number of positive nodes, ER and PR expression, PR group, Ki-67 group and NPI). Based on OOM for pN0 cases, significant associations were established in three characteristics (Ki-67 group, grade and NPI group). For pN1 cases OOM found significant associations in seven characteristics (PR group, PNI, LVI, Ki-67 group, grade, NPI group and number of positive nodes). Conclusion: First in oncology, OOM was applied, which found some other significant characteristics associated with RS than traditional statistical methods. There were few patients, where no clinical associations were found between characteristics and RS contrary to statistically significant differences. Therefore, the results of these statistical analyses can be neither applied for individual cases nor able to provide the bases for screening patients, i.e., whether they need for OncotypeDX testing or not. OncotypeDX still provides a personalised approach in BC.

Contemporary trends in breast cancer in females under the age of fifty: An NCDB study

IntroductionBreast cancer among patients under 50 years old accounts for 18% of new cases. Few studies have reported current trends in clinical-pathologic features and treatment patterns for young patients. We evaluated these trends in a modern cohort of breast cancer patients under 50. MethodsWe identified women with breast cancer from the National Cancer Database from 2004–2017. Patients were grouped into 18–29, 30–39, 40–49, and ≥ 50-year cohorts. Proportions and temporal comparisons between demographic, clinicopathologic features, and treatment types were evaluated. Temporal trends across sequential periods were performed. ResultsOf the 2387,902 patients selected, 554,941 (23.3%) were younger than 50. During 2004–2017, the proportions remained stable in the 18–29 (0.5–0.6%) and 30–39 (4.5–5%) age groups, while decreasing in the 40–49 group (absolute difference: −4.8%, p < 0.001). Overall, in those younger than 50, early-stage breast cancer (clinical stage 0-II) increased by 3.9%, while stages III and IV decreased by 2.7% and 1.3% (p < 0.001), respectively. Mastectomy rates and neoadjuvant systemic therapy use increased by 10.4% and 9.8%, respectively (p < 0.001) in all groups under 50. ConclusionsDespite stable proportions in the youngest age groups (18–29 and 30–39), a noteworthy decrease in the 40–49 age group was observed, suggesting potential shifts in disease detection. The rise in early-stage disease and neoadjuvant systemic therapies should theoretically translate into an increase in the number of breast-conserving candidates. However, the increase in mastectomies highlights the need to better understand the factors influencing treatment decisions in this population.

Abstract LB419: Neuroinflammation and aromatase inhibitor associated musculoskeletal syndrome (AIMSS) in breast cancer: Initial insights from [11C]PBR28 PET/MR imaging

Abstract Introduction: While 5-10 years of aromatase inhibitor (AI) treatment clearly improves survival rates of postmenopausal women with hormone-sensitive breast cancer, up to 85% of AI users report aromatase inhibitor associated musculoskeletal syndrome (AIMSS, including arthralgias, myalgias, and muscle stiffness). The biological mechanisms underlying AIMSS are not well understood, but accumulating preclinical and clinical evidence implicate an important role for neuroinflammation in the development and maintenance of other types of chronic musculoskeletal pain (e.g., low back pain, fibromyalgia etc.). The purpose of this pilot study was to investigate the role of neuroinflammation in breast cancer patients with AIMSS. Methods: This cross-sectional case control study used Siemens 3 T integrated positron emission tomography-magnetic resonance imaging (PET/MRI) with the radioligand [11C]PBR28, which binds to the neuroinflammation marker 18kDa translocator protein (TSPO), to assess neuroinflammation in two cohorts (chronic AIMSS, no-AIMSS) of breast cancer patients undergoing AI therapy, and age-, sex- and TSPO genotype-matched healthy controls. Static [11C]PBR28 PET images were reconstructed from 60-90 minutes post-injection. Standardized uptake value (SUV) maps were obtained voxel-wise by normalizing radioactivity by injected dose/body weight. SUV maps were normalized to whole brain to obtain SUV ratio (SUVR) maps. SUVR images spatially normalized to MNI template and then spatially smoothed (FWHM=8mm). Results: Two breast cancer patients (1 AIMSS, 1 no-AIMSS) and 2 matched healthy controls were included in this analysis. Compared to their individual matched healthy controls, both breast cancer patients showed increased [11C]PBR28 signal uptake in the thalamus/midbrain and pons. This elevated signal was more prominent in the breast cancer patient with AIMSS. Conclusions: These preliminary findings suggest an elevated signal of neuroinflammation in the thalamus and brainstem in AI-treatment and AIMSS, aligning with existing literature emphasizing their pivotal role in chronic pain pathology. While it is imperative to acknowledge the limitation of a small sample size, these promising findings suggest a potential role of neuroinflammation for the first time in AIMSS. Future focused Region of Interest (ROI) analysis in thalamus and brainstem with a larger sample size may confirm. Citation Format: Yehui Zhu, Natalie Swanson, Jennifer Murphy, Minhae Kim, Ann Partridge, Robert Edwards, Kristin Schreiber, Marco Loggia. Neuroinflammation and aromatase inhibitor associated musculoskeletal syndrome (AIMSS) in breast cancer: Initial insights from [11C]PBR28 PET/MR imaging [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 LB419.

Abstract LB009: Unveiling the significance of DARPP-32 and its partners, including GRB7 and DKK1, in breast cancer: Integrative insights from patient data and cell line transcriptomics

Abstract DARPP-32 plays a crucial role in regulating both protein-phosphatase-1 (PP-1) and protein kinase A (PKA), its function being reliant on its phosphorylation status. We have previously demonstrated that low DARPP-32 expression is associated with adverse survival of breast cancer patients, particularly those with oestrogen receptor (ER) positive disease; however, there is limited information on how DARPP-32 may alter breast cancer cell behaviour. We have recently published an integrative approach using patient data and cell line transcriptomics to understand the role of DARPP-32 in breast cancer. We analysed the transcriptome of T47D ER positive breast cancer cells following DARPP-32 knockdown, including treatments in combination with 17β-estradiol or PKA inhibitor fragment (6-22) amide. 202 differentially expressed transcripts were identified in DARPP-32 knock down cells and treatment of these cells with 17β-estradiol or PKA inhibitor fragment (6-22) amide led to the differential expression of 193 and 181 transcripts respectively. Differentially expressed transcripts were compared with genes identified as associated with DARPP-32 expression in 1980 breast cancer patients within the METABRIC cohort using an Artificial Neural Network approach (ANN). Several genes overlapped with those identified from cell line transcriptomics, including PTK7, TRAF5, and KLK6. Both DKK1 and GRB7 were identified as genes associated with DARPP-32 expression in patients using ANN, therefore protein expression was determined in a large cohort of early-stage breast cancer patients (n&amp;gt;1000). We demonstrated that DKK1 and GRB7 protein expression was significantly correlated with DARPP-32 Threonine-34 phosphorylation levels within the same samples (all P&amp;lt;0.05). We have now applied an ANN-based integrative data mining approach to identify genes with the largest effect on other genes resulting in an interactome map, which was based on genes identified within the cell line transcriptomics and original ANN. 1878 genes were identified for inclusion within an interactome map in the total patient cohort, whereas 1003 were identified in ER negative disease alone and 2144 in ER positive disease alone. Pathway enrichment analysis identified the ubiquitin proteosome pathway, the insulin pathway-protein kinase B signalling cascade and the RAS pathway. This study underscores the significance of DARPP-32, a central molecular switch, in breast cancer, elucidating its impact on patient prognosis and highlighting potential molecular targets for therapeutic intervention. The integrative approach combining patient data with cell line transcriptomics provides insights into the complex mechanisms underlying breast cancer progression and opens avenues for further research and targeted interventions. Citation Format: Behnaz Saidy, Richa Vasan, Megan-Rose Greener, Rosie Durrant, Adelynn Immanuel, Andrew Green, Emad Rakha, Ian Ellis, Graham Ball, Stewart Martin, Sarah J. Storr. Unveiling the significance of DARPP-32 and its partners, including GRB7 and DKK1, in breast cancer: Integrative insights from patient data and cell line transcriptomics [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 LB009.