Abstract 6546: Spatial immunology landscapes that correlate with survival in triple negative breast cancer

Abstract Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer characterized by negative immunohistochemistry staining for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Treatment options for TNBCs are limited due to lack of tumor-specific targeted therapies, resulting in poor prognosis and patient survival. This is exacerbated by lack of prognostic markers of response. While current studies suggest tumor immune interactions are important, current immune activity quantifications, such as scores quantifying abundance of tumor-infiltrating lymphocytes (TILs), are not sufficient to define tumor immune status. We used imaging mass cytometry (IMC) to measure 33 markers on primary tumors of 100 patients undergone chemotherapy with long-term follow-up to explore the tumor immune microenvironment of TNBCs. Concordant with previous studies, a higher ratio of T-cells was associated with response to chemotherapy and longer overall survival (adjusted p-value0. 05). Moreover, using Kmeans clustering we identified 13 distinct cellular neighborhoods, reflective of the heterogenous nature of TNBCs. Among others, we identified a neighborhood, characterized by low CD14+ expression, low cytokeratin, high vimentin expression and high CD45RO, that contributes highest impact on correlation with overall survival (adjusted p-value0. 01). These results suggest an important role for memory T cells in the stroma. Thus, resolving spatial organization of the tissue is important to understanding patient response to therapy in TNBCs. Citation Format: Ali Foroughi pour, Jan Martinek, Te-Chia Wu, Santhosh Sivajothi, Zichao Liu, Jie Zhou, David Rimm, Paul Robson, Katherine Bates, Karolina Palucka, Jeffrey H. Chuang. Spatial immunology landscapes that correlate with survival in triple negative breast cancer abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 6546.