Response In Triple-negative Breast Cancer Research Articles

Predicting Response of Triple-Negative Breast Cancer to Neoadjuvant Chemotherapy Using a Deep Convolutional Neural Network-Based Artificial Intelligence Tool.

Achieving a pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) is associated with improved patient outcomes in triple-negative breast cancer (TNBC). Currently, there are no validated predictive biomarkers for the response to NAC in TNBC. We developed and validated a deep convolutional neural network-based artificial intelligence (AI) model to predict the response of TNBC to NAC. Whole-slide images (WSIs) of hematoxylin and eosin-stained core biopsies from 165 (pCR in 60 and non-pCR in 105) and 78 (pCR in 31 and non-pCR in 47) patients with TNBC were used to train and validate the model. The model extracts morphometric features from WSIs in an unsupervised manner, thereby generating clusters of morphologically similar patterns. Downstream ranking of clusters provided regions of interest and morphometric scores; a low score close to zero and a high score close to one represented a high or low probability of response to NAC. The predictive ability of AI score for the entire cohort of 78 patients with TNBC ascertained by receiver operating characteristic analysis demonstrated an area under the curve (AUC) of 0.75. The AUC for stages I, II, and III disease were 0.88, 0.73, and 0.74, respectively. Using a cutoff value of 0.35, the positive predictive value of the AI score for pCR was 73.7%, and the negative predictive value was 76.2% for non-pCR patients. To our knowledge, this study is the first to demonstrate the use of an AI tool on digitized hematoxylin and eosin-stained tissue images to predict the response to NAC in patients with TNBC with high accuracy. If validated in subsequent studies, these results may serve as an ancillary aid for individualized therapeutic decisions in patients with TNBC.

Abstract P1-06-02: The effect of race on pathologic complete response rates and overall survival in patients with triple negative breast cancer

Abstract Introduction: Despite the recent overall improvement in survival for patients with breast cancer, racial disparities in outcomes persist. While studies have demonstrated that socioeconomic factors and access to treatment play a role, differences in tumor biology may also contribute. Black women are significantly more likely to develop triple negative breast cancer (TNBC), the deadliest of the breast cancer subtypes, with more TNBC patients progressing to incurable, metastatic disease than patients with any other breast cancer subtype. Studies have demonstrated that TNBC patients who achieve a pathologic complete response (pCR), defined as no residual invasive cancer in the breast or lymph nodes after neoadjuvant chemotherapy (NAC), have improved survival. We hypothesize that rates of pCR and overall survival (OS) in patients with TNBC may differ by race/ethnicity, which may account in part for the disparities in outcomes observed. Methods: Adult female patients with stage I-III TNBC diagnosed in 2010-2019 who received NAC followed by surgery were identified from the National Cancer Database (NCDB). Race/ethnicity was defined as Hispanic (H), Non-Hispanic White (NHW), Non-Hispanic Black (NHB), Non-Hispanic Asian (NHA), and Non-Hispanic Other (NHO). pCR was defined as no invasive cancer in either the breast or axilla (ypT0/is,N0) at surgery. Logistic regression was used to estimate the association of race/ethnicity with achievement of pCR after adjustment for covariates. Unadjusted OS was estimated using the Kaplan-Meier method, and the log-rank test was used to compare groups. Cox Proportional Hazards models were used to estimate the association of race/ethnicity and achievement of pCR with OS after adjustment for covariates. Additional interaction and subgroup analyses were also conducted. Results: Of the 40,890 patients identified, 29.8% (n=12,173) demonstrated pCR after NAC. The unadjusted 5-year OS rates for those who achieved pCR were significantly higher compared to patients with no pCR (0.917, 95% CI 0.911-0.923 vs 0.667, 95% CI 0.661-0.673, log-rank p< 0.001). Hispanic patients were more likely to achieve pCR (OR 1.19, 95% CI 1.08-1.31, p=0.001), and NHB patients were less likely to achieve pCR (OR 0.89, 95% CI 0.83-0.95, p=0.001) compared to NHW, even after adjustment. Unadjusted OS was also notably lower for NHB patients compared to every other race group (5-year OS rate: NHB 0.709 vs NHW 0.746 vs NHO 0.771 vs H 0.772 vs NHA 0.816, log-rank p< 0.001); however, this difference did not persist after adjustment for patient and disease factors, including achievement of pCR. Interval from diagnosis to start of chemotherapy (OR 0.95, 95% CI 0.94-0.96, p< 0.001) and duration after chemotherapy start to surgery (OR 1.02, 95% CI 1.02-1.03, p< 0.001) were associated with the odds of achieving pCR. Overall, the effect of achieving pCR on OS did not differ by race/ethnicity (interaction p=0.10). Discussion: Achieving pCR after NAC in patients with TNBC is associated with a significant improvement in OS. Yet, rates of pCR appear to differ based on race/ethnicity, with NHB patients demonstrating significantly lower rates of pCR than NHW patients, which may contribute to the disparities in survival outcomes observed. In addition to addressing socioeconomic factors and access to treatment, further research examining whether biological differences exist based on race that influence response of TNBC to current standard therapies is essential for improving survival outcomes for this disproportionately affected patient population. Citation Format: Hannah E. Woriax, Samantha M. Thomas, Jennifer K. Plichta, Laura H. Rosenberger, Astrid Botty van de bruele, Akiko Chiba, Gayle DiLalla, Carolyn Menendez, E Shelley Hwang, Maggie L. DiNome. The effect of race on pathologic complete response rates and overall survival in patients with triple negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-06-02.

Systemic immune mediators reflect tumour-infiltrating lymphocyte intensity and predict therapeutic response in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer (BC). Neoadjuvant chemotherapy has proven efficacy in its treatment, and a pathological complete response (pCR) to therapy is predictive of improved long-term survival. The immune response is key to successful neoadjuvant chemotherapy, as indicated by the relation between the percentage of stromal tumour-infiltrating lymphocytes (TILs) in pre-treated tumour tissue samples and the likelihood of achieving pCR. Here we studied systemic immune mediators from volunteer TNBC patients before undergoing neoadjuvant chemotherapy to determine the systemic response association with TIL intensity, treatment response and survival. Patients were classified into pCR responder or non-responder at time of surgery. We found higher levels of immune mediators before treatment began in patients that went on to be pCR responders versus non-pCR, with area under the curve (AUC) values of 0.64-0.80. We also observed a positive correlation between inflammatory systemic immune mediators and the percentage of TILs in pCR responder patients. Combining TILs and systemic immune mediator levels provided stronger AUC values (range of 0.72-0.82). Last, performing a progression-free survival analysis with several of the systemic cytokines that predict pCR, segregated the patients into long- and short-survival groups based on high and low production of the cytokines, respectively. Our study demonstrates that circulating cytokines, before treatment begins, predict pCR in TNBC patients treated with neoadjuvant chemotherapy. Moreover, they may act as a surrogate marker of high TILs or together with TILs to better predict pCR and survival.

Stromal grading predicts pathologic complete response and prognosis in triple-negative breast cancer.

Do traditional prognostic factors fully account for the diversity of clinical behavior in breast cancer? Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer seen to have a poor prognosis, although there is great variation in clinical outcomes. Most recently, novel approaches have targeted the tumoral microenvironment (TME) to determine prognosis and tumor-associated stroma has become increasingly recognized as a potential biomarker to predict treatment response and prognosis in TNBC. The principle aim of this paper is to demonstrate an approach to stromal grading in TNBC, with consideration of its utility for predicting pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC) and clinical survival outcomes. We evaluated 152 TNBC cases from the Firehose Legacy TCGA Cohort and validated our findings in a series of 110 patients from our health system. Stromal grading correlated with clinical outcomes related to prognosis and response to NAC, advanced pathologic stage, as well as clinical demographics like age over 50years with good interobserver reliability (83.6-89.1%). Looking forward, the TME could carve out a more precision-based care in TNBC and breast cancer generally.

Assessment of Response to Neoadjuvant Systemic Treatment in Triple-Negative Breast Cancer Using Functional Tumor Volumes from Longitudinal Dynamic Contrast-Enhanced MRI

Early assessment of neoadjuvant systemic therapy (NAST) response for triple-negative breast cancer (TNBC) is critical for patient care in order to avoid the unnecessary toxicity of an ineffective treatment. We assessed functional tumor volumes (FTVs) from dynamic contrast-enhanced (DCE) MRI after 2 cycles (C2) and 4 cycles (C4) of NAST as predictors of response in TNBC. A group of 100 patients with stage I-III TNBC who underwent DCE MRI at baseline, C2, and C4 were included in this study. Tumors were segmented on DCE images of 1 min and 2.5 min post-injection. FTVs were measured using the optimized percentage enhancement (PE) and signal enhancement ratio (SER) thresholds. The Mann-Whitney test was used to compare the performance of the FTVs at C2 and C4. Of the 100 patients, 49 (49%) had a pathologic complete response (pCR) and 51 (51%) had a non-pCR. The maximum area under the receiving operating characteristic curve (AUC) for predicting the treatment response was 0.84 (p < 0.001) for FTV at C4 followed by FTV at C2 (AUC = 0.82, p < 0.001). The FTV measured at baseline was not able to discriminate pCR from non-pCR. FTVs measured on DCE MRI at C2, as well as at C4, of NAST can potentially predict pCR and non-pCR in TNBC patients.

Ethnic disparities in the immune microenvironment of triple negative breast cancer and its role in therapeutic outcomes.

In 2020, newly diagnosed breast cancer (BC) cases surpassed that of lung cancer among women, making it the most common female cancer globally. In spite of recent increases in incidence rates, mortality due to BC has declined since 1989. These declines have been attributed to advancements in treatment modalities as well as increased mammography surveillance. Despite these advances, African American (AA) women are 40% more likely to die from BC than Caucasian women. Multifactorial etiology has been implicated in the disparity of BC mortality rates among AA women. As an example, AA women have a disproportionate incidence of triple negative breast cancer (TNBC), which has a poor prognosis and marginal treatment options. Increasingly, the tumor microenvironment (TME) has gained relevance as it relates to primary tumor progression, metastasis and treatment possibilities. The treatment outcomes or pathological complete response (pCR) in TNBC among AA women are affected by differences in TME. The TME of AA women exhibit several variances in acellular and cellular components associated with pro-tumorigenic effects. For example, increased levels of the adipocyte-related hormone, resistin, the pro-inflammatory cytokine, IL-6, and the CC chemokine, CCL2, within the TME of AA women gives rise to an increased density of M2 macrophages, also known as tumor-associated macrophages. Elevated levels of vascular endothelial growth factor in the TME of AA women increase the vascular density or vascularity, which facilitate aggressive tumor growth and metastasis. Furthermore, a pro-tumorigenic TME is supported by increased levels of the CXC chemokine, CXCL12 that results in the recruitment of regulatory T lymphocytes (Tregs ). Due to these and other differences in the TME of AA women, precision oncology can target specific aspects of the TME that may contribute to a poorer prognosis. In addition to the discrepancies in the TME, AA women face socio-economic barriers that limit their ability to access state-of-the-art, novel therapies against metastatic TNBC. In this review, we will provide a brief overview of the tumor immune microenvironment, immune-based treatment options for TNBC and their potential to decrease health disparities due to ethnicity.

Triple negative breast cancer: Immunogenicity, tumor microenvironment, and immunotherapy.

Triple negative breast cancer (TNBC) is a biologically diverse subtype of breast cancer characterized by genomic and transcriptional heterogeneity and exhibiting aggressive clinical behaviour and poor prognosis. In recent years, emphasis has been placed on the identification of mechanisms underlying the complex genomic and biological profile of TNBC, aiming to tailor treatment strategies. High immunogenicity, specific immune activation signatures, higher expression of immunosuppressive genes and higher levels of stromal Tumor Infiltrating Lymphocytes, constitute some of the key elements of the immune driven landscape associated with TNBC. The unprecedented response of TNBC to immunotherapy has undoubtedly changed the standard of care in this disease both in the early and the metastatic setting. However, the extent of interplay between immune infiltration and mutational signatures in TNBC is yet to be fully unravelled. In the present review, we present clinical evidence on the immunogenicity and tumour microenvironment influence on TNBC progression and the current treatment paradigms in TNBC based on immunotherapy.

Identification of an immune classifier for predicting the prognosis and therapeutic response in triple-negative breast cancer

Identification of an immune classifier for predicting the prognosis and therapeutic response in triple-negative breast cancer

Enzymatic Digestion of Cell-surface Heparan Sulfate Alters the Radiation Response in Triple-negative Breast Cancer Cells

Radiation resistance represents a major challenge in the treatment of breast cancer. As heparan sulfate (HS) chains are known to contribute to tumorigenesis, we aimed to investigate the interplay between HS degradation and radiation response in triple-negative breast cancer (TNBC) cells. HS chains were degraded in vitro as TNBC cells MDA-MB-231 and HCC1806 were treated with heparinase I and III. Subsequently, radioresistance was determined via colony formation assay after doses of 2, 4 and 6 Gy. Cell cycle profile, stem cell characteristics, expression of HS, activation of beta integrins, and apoptosis were determined by flow cytometry. Additionally, cell motility was analyzed via wound-healing assays, and expression and activation of FAK, CDK-6, Src, and Erk1/2 were quantified by western blot pre- and post-irradiation. Finally, the expression of cytokines was analyzed using a cytokine array. Radiation promoted cell cycle changes, while heparinase treatment induced apoptosis in both cell lines. Colony formation assays showed significantly increased radio-resistance for both cell lines after degradation of HS. Cell migration was similarly upregulated after degradation of HS compared to controls. This effect was even more prominent after irradiation. Interestingly, FAK, a marker of radioresistance, was significantly activated in the heparinase-treated group. Additionally, we found Src to be dysregulated in MDA-MB-231 cells. Finally, we observed differential secretion of GRO, CXCL1, IGFBP1, IL8, Angiogenin, and Osteoprotegerin after HS degradation and radiotherapy. Our results suggest an influence of HS chains on the development of radioresistance in TNBC.

In This Issue

In This Issue

Identification and Validation of a Novel Glycolysis-Related Gene Signature for Predicting the Prognosis and Therapeutic Response in Triple-Negative Breast Cancer.

A high malignancy rate and poor prognosis are common problems with triple-negative breast cancer (TNBC). There is increasing evidence that glycolysis plays vital roles in tumorigenesis, tumor invasion, immune evasion, chemoresistance, and metastasis. However, a comprehensive analysis of the diagnostic and prognostic significance of glycolysis in TNBC is lacking. Transcriptomic and clinical data of TNBC patients were obtained from The Cancer Genome Atlas (TCGA) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) databases, respectively. Glycolysis-related genes (GRGs) were collected from the Molecular Signatures Database (MSigDB). Differential comparative analysis was performed to obtain the differentially expressed (DE)-GRGs associated with TNBC. Based on the DE-GRGs, a glycolysis-related risk signature was established using Least Absolute Shrinkage and Selector Operation (LASSO) and multivariable Cox regression analyses. The prognostic value, tumor microenvironment, mutation status, and chemotherapy response of different risk groups were analyzed. An independent cohort from the METABRIC database was used for external validation. Furthermore, the expression patterns of five genes derived from the prognostic model were validated by quantitative real-time polymerase chain reaction (RT-qPCR). The glycolysis-related prognostic signature included five genes (IFNG, ACSS2, IRS2, GFUS, and GAL3ST1) and predicted the prognosis of TNBC patients independent of clinical factors (p < 0.05). Patients were divided into high- and low-risk groups based on the median risk score. Compared to low-risk TNBC patients, high-risk patients had significantly decreased overall survival (HR = 2.718, p < 0.001). Receiver operating characteristic and calibration curves demonstrated that the model had high performance in terms of predicting survival and risk stratification. The results remained consistent after external verification. Additionally, the tumor immune microenvironment significantly differed between the risk groups. Low-risk TNBC patients had a better immunotherapy response than high-risk patients. High-risk TNBC patients with a poor prognosis may benefit from targeted therapy. This study developed a novel glycolysis and prognosis-related (GRP) signature based on GRGs to predict the prognosis of TNBC patients, and may aid clinical decision-making for these patients.

P53 Missense Mutation is Associated with Immune Cell PD-L1 Expression in Triple-Negative Breast Cancer

The programmed death ligand 1 (PD-L1) is a pivotal biomarker of immunotherapy in triple negative breast cancer (TNBC). TP53 is reported as a positive regulatory predictor of immune efficacy. The correlation of p53 expression or mutation and PD-L1 expression is explored. By immunohistochemistry, PD-L1 expression between p53 mutation (missense and nonsense) and wild type; p53 no-expression/loss vs. expression were compared. There was a significant association between p53 mutation, especially missense mutation with higher histological grade, and PD-L1 expression in immune cells (ICs). Both p53 missense mutation and PD-L1 expression may be potential targets for improving immunotherapy response in TNBC.

Hypoxia-Inducible Expression of Annexin A6 Enhances the Resistance of Triple-Negative Breast Cancer Cells to EGFR and AR Antagonists.

Physiological changes such as hypoxia in the tumor microenvironment (TME) endow cancer cells with malignant properties, leading to tumor recurrence and rapid progression. Here, we assessed the effect of hypoxia (1% Oxygen) on the tumor suppressor Annexin A6 (AnxA6) and the response of triple-negative breast cancer (TNBC) cells to epidermal growth factor receptor (EGFR) and androgen receptor (AR) targeted therapies. We demonstrate that brief exposure of TNBC cells to hypoxia (within 24 h) is associated with down regulation of AnxA6 while > 24 h exposure cell type dependently stimulated the expression of AnxA6. Hypoxia depicted by the expression and stability of HIF-1/2α led to up regulation of the HIF target genes SLC2A1, PGK1 as well as AR and the AR target genes FABP-4 and PPAR-γ, but the cellular levels of AnxA6 protein decreased under prolonged hypoxia. Down regulation of AnxA6 in TNBC cells inhibited, while AnxA6 over expression enhanced the expression and cellular levels of HIF-1/2α, SLC2A1 and PGK1. RNAi mediated inhibition of hypoxia induced AnxA6 expression also strongly inhibited glucose uptake and ROS production in AnxA6 expressing TNBC cells. Using a luciferase reporter assay, we confirm that short-term exposure of cells to hypoxia inhibits while prolonged exposure of cells to hypoxia enhances AnxA6 promoter activity in HEK293T cells. Compared to cells cultured under normoxia, TNBC cells were more resistant to lapatinib under hypoxic conditions, and the downregulation of AnxA6 sensitized the cells to EGFR as well as AR antagonists. These data suggest that AnxA6 is a hypoxia inducible gene and that targeting AnxA6 upregulation may be beneficial in overcoming TNBC resistance to EGFR and/or AR targeted therapies.

A Catalytic Immune Activator Based on Magnetic Nanoparticles to Reprogram the Immunoecology of Breast Cancer from "Cold" to "Hot" State.

Triple-negative breast cancer (TNBC) as "cold" tumor is characterized by severe immunosuppression of the tumor microenvironment (TME). To effectively activate the immune response of TNBC, a new kind of therapy strategy called cancer catalytic immunotherapy is proposed based on magnetic nanoparticles (NPs) as immune activators. Utilizing the weak acidity and excessive hydrogen peroxide of TME, these magnetic NPs can release ferrous ions to promote Fenton reaction, leading to abundant ·OH and reactive oxygen species (ROS) for ultimately killing cancer cells. Mechanistically, these magnetic NPs activate the ROS-related signaling pathway to generate more ROS. Meanwhile, these magnetic NPs with unique immunological properties can promote the maturation of dendritic cells and the polarization of macrophages from M2 to M1, resulting in the infiltration of more T cells to reprogram the immunoecology of TNBC from "cold" to "hot" state. Besides directly affecting immune cells, these magnetic NPs can also affect the secretion of some immune-related cytokines by cancer cells, to further indirectly activate the immune response. In conclusion, these catalytic immune activators are designed to achieve the synergistic treatment of chemodynamic therapy-enhanced immunotherapy guided by computed tomography (CT)/near-infrared region-II (NIR-II) dual-mode imaging, providing a new strategy for TNBC treatment.

Label-free metabolic imaging for sensitive and robust monitoring of anti-CD47 immunotherapy response in triple-negative breast cancer

BackgroundImmunotherapy is revolutionizing cancer treatment from conventional radiotherapies and chemotherapies to immune checkpoint inhibitors which use patients’ immune system to recognize and attack cancer cells. Despite the huge clinical success...

Proteogenomic Markers of Chemotherapy Resistance and Response in Triple-Negative Breast Cancer.

Proteogenomic analysis of triple-negative breast tumors revealed a complex landscape of chemotherapy response associations, including a 19q13.31-33 somatic deletion encoding genes serving lagging-strand DNA synthesis (LIG1, POLD1, and XRCC1), that correlate with lack of pathologic response, carboplatin-selective resistance, and, in pan-cancer studies, poor prognosis and CIN. This article is highlighted in the In This Issue feature, p. 2483.

Abstract 118: BACH1 is an oxygen-sensitive mediator of the hypoxia response in triple-negative breast cancer

Abstract Triple-negative breast cancer (TNBC) is an aggressive solid tumor characterized by a hypoxic phenotype that promotes metastatic progression and resistance to therapy. The canonical cellular response to hypoxia is largely driven by hypoxia inducible factors (HIFs) that stimulate transcription of genes related to angiogenesis, cancer stem cells, cell survival, and glucose and iron metabolism. There is growing evidence that several factors, in addition to HIFs, contribute to the tumor hypoxia response. Thus, identifying novel mechanisms that regulate this cellular response in addition to the HIFs is key to our understanding of hypoxia and could have direct clinical impact. High expression of BTB and CNC homology 1 (BACH1), a heme-regulated bZIP transcription factor, drives metastatic progression in various cancers including TNBC. While BACH1 has been shown to be induced under hypoxia in some cell lines, its regulation and role in hypoxia signaling, specifically with regards to cancer cells, is poorly understood. Here we report a novel regulatory pathway of the tumor hypoxia response in TNBC. We show that BACH1 is post-translationally prolyl-hydroxylated by the HIF prolyl-hydroxylases (PHDs) in an oxygen-dependent and NRF2/HMOX1-independent manner. Hypoxic exposure thus stabilizes BACH1 protein and enhances its DNA binding activity at loci of both canonical and hypoxia-specific downstream targets. We further show that BACH1 regulates the hypoxia response by promoting expression of both HIF-dependent and HIF-independent hypoxia-induced genes in TNBC cells. Our findings describe BACH1 as a novel oxygen-sensitive effector of the hypoxia response in TNBC that represents an alternative target for attenuating hypoxia-induced, pro-metastatic signaling and therapeutic resistance. Citation Format: Christopher M. Dann, Long C. Nguyen, Dongbo Yang, Joseph P. Wynne, Andrea Valdespino, Letícia Stock, Marsha R. Rosner. BACH1 is an oxygen-sensitive mediator of the hypoxia response in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 118.

Abstract 2050: Treatment with anti-PD-1 monoclonal antibody increases levels of MIP-1α and other cytokines, and suppresses tumor growth in a mouse model of triple negative breast cancer

Abstract Background: Triple negative breast cancer (TNBC), characterized by the lack of estrogen and progesterone receptors and HER2, is an aggressive form of breast cancer that accounts for 15-20% of all diagnosed cases. There are few targeted therapies available for TNBC, but immune checkpoint inhibitors (ICIs) such as Pembrolizumab have been shown to be effective in a subset of TNBC patients. However, because ICIs are rarely administered as a monotherapy, there remains little foundational understanding of how single-agent immunotherapies alter the immune landscape and which circulating immune profiles predict therapeutic response in TNBC. Therefore, further investigation into the distinct immune signatures of ICIs are necessary for developing a rational basis for selecting optimal treatment regimens for TNBC. Methods: E0771 cells, a C57Bl/6 mouse-derived TNBC cell line, were injected into the bilateral mammary pads of 8 week old female C57Bl/6J mice. Control mice were injected with saline into mammary pads. After tumors developed (14 days post-implantation), E0771 mice received 200 ug doses of immunotherapy (anti-PD-1, anti-LAG-3, or anti-TIM-3 antibodies) or IgG isotype control every four days. After 3 doses, treatments were stopped and serum was collected from “on-treatment” mice. Fourteen days after the third treatment, serum was collected from “post-treatment” mice. A panel of 31 cytokines, chemokines, and growth factors were analyzed in “pre-treatment”, “on-treatment”, “post-treatment”, and saline control mouse serum using a BioPlex 200 multiplex system (Eve Technologies). Results: Mice treated with anti-PD-1 antibody showed significantly higher levels of several cytokines and chemokines compared to isotype control mice. Among the most significantly increased cytokines in the post-treatment anti-PD-1 group was macrophage inflammatory protein-1α (MIP-1α), or CCL3. MIP-1α is a chemotactic cytokine secreted by several types of immune cells that is known to attract macrophages and CD8+ T cells. More subtle changes in levels of several cytokines, chemokines, and growth factors were observed in anti-LAG-3 and anti-TIM-3 treatment groups. At the post-treatment timepoint, mice treated with anti-PD-1 antibody had smaller tumor sizes than mice treated with anti-LAG-3 and anti-TIM-3 antibodies, indicating that PD-1 blockade slows tumor growth and disease progression. Conclusion: Anti-PD-1 treatment induced more distinct circulating immune profiles and was more effective at controlling tumor growth than anti-LAG-3 and anti-TIM-3 treatments. These results may also suggest MIP-1α-mediated tumor regression in response to anti-PD-1 treatment in TNBC. Citation Format: Payton De La Cruz, Kathryn Grive, Jennifer Ribeiro. Treatment with anti-PD-1 monoclonal antibody increases levels of MIP-1α and other cytokines, and suppresses tumor growth in a mouse model of triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2050.

Abstract 2736: Forecasting treatment response to neoadjuvant therapy in triple-negative breast cancer via an image-guided digital twin

Abstract Introduction: Patients with locally advanced, triple-negative breast cancer (TNBC) typically receive neoadjuvant therapy (NAT) to downstage the tumor and to improve the outcome of subsequent breast conservation surgery. There are currently no methods to accurately predict how a TNBC patient will respond to NAT before surgery. In this work, we applied a digital twin framework to address this unmet clinical need, by integrating quantitative magnetic resonance imaging (MRI) data with mechanism-based mathematical modeling. Methods: Multiparametric MRI was acquired in patients (N = 50) before, after 2 and 4 cycles of Adriamycin/Cyclophosphamide (A/C), and again after 12 cycles of Paclitaxel as part of the ARTEMIS (NCT02276433) trial. Within each imaging session, dynamic contrast-enhanced (DCE) MRI, diffusion-weighted imaging (DWI), and a pre-contrast T1-map were acquired. The images were processed by a pipeline consisting of motion correction, multiparametric image alignment, inter-visit image registration to align the tumor and surrounding breast tissue, tissue segmentation, and estimation of tumor cellularity from DWI. A mechanism-based mathematical model, a reaction-diffusion equation, is used to characterize the mobility of tumor cells via diffusion damped by mechanical tissue properties, tumor proliferation via logistic growth, and treatment-induced cell death via the delivery and decay of therapies. For each patient, pre-treatment images were used for model initialization. The model calibration and prediction were implemented with two strategies: 1) using images acquired during the A/C for calibration and predicting up to the end of A/C, and 2) using images acquired during and after the A/C for calibration and predicting up to the end of NAT. For strategy 1), we evaluated the model by comparing its predicted tumor volume and total tumor cellularity to the imaging measurements at the end of A/C. For strategy 2), we evaluated the model by comparing its predicted final response to the post-surgical pathological findings. Results: For strategy 1), our framework predicted the change of tumor volume and total tumor cellularity with Pearson correlation coefficients of 0.91 and 0.89, respectively. Regarding strategy 2), our framework achieved an area under the receiver operator characteristic curve of 0.88 for distinguishing pCR from non-pCR. As a comparison, imaging measurement of tumor volume at the end of A/C achieved an AUC of 0.79. Conclusion: Our approach successfully captures the patient-specific dynamics of TNBC response to NAT and provides an improved prediction of final response, which demonstrates the potential of a digital twin framework to be a powerful tool for predicting response to NAT. Once validated, the method will provide a unique opportunity for optimizing treatment plans on a patient-specific basis. Citation Format: Chengyue Wu, Angela M. Jarrett, Zijian Zhou, Nabil Elshafeey, Beatriz E. Adrada, Rosalind P. Candelaria, Rania Mohamed, Medine Boge, Lei Huo, Jason White, Debu Tripathy, Vicente Valero, Jennifer Litton, Clinton Yam, Jong Bum Son, Jingfei Ma, Gaiane M. Rauch, Thomas E. Yankeelov. Forecasting treatment response to neoadjuvant therapy in triple-negative breast cancer via an image-guided digital twin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2736.

PRMT inhibition induces a viral mimicry response in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype with the worst prognosis and few effective therapies. Here we identified MS023, an inhibitor of type I protein arginine methyltransferases (PRMTs), which has antitumor growth activity in TNBC. Pathway analysis of TNBC cell lines indicates that the activation of interferon responses before and after MS023 treatment is a functional biomarker and determinant of response, and these observations extend to a panel of human-derived organoids. Inhibition of type I PRMT triggers an interferon response through the antiviral defense pathway with the induction of double-stranded RNA, which is derived, at least in part, from inverted repeat Alu elements. Together, our results represent a shift in understanding the antitumor mechanism of type I PRMT inhibitors and provide a rationale and biomarker approach for the clinical development of type I PRMT inhibitors.