Abstract 5313: Spatial transcriptomics reveals clone-specific features of primary and metastatic tumors in triple-negative breast cancer

Abstract Breast cancer has become the most commonly diagnosed malignancy, with metastasis remaining the leading cause of mortality, particularly in triple-negative breast cancer (TNBC). In this study, we applied spatial transcriptomics with an 8 μm resolution to analyze the primary tumor and lung metastasis, occurring six months post-recurrence, of a TNBC patient, encompassing a total of 1, 033, 074 bins. Through this analysis, six tumor clusters (T0-T5) with distinct gene expression profiles were identified. Among these, T0 and T3 were the predominant clusters observed in the metastatic tumor. T0 was primarily distributed in the tumor core, while T3 localized at the tumor boundary. Both clusters exhibited high expression of VIM, a marker associated with epithelial-mesenchymal transition (EMT). Differentially expressed gene (DEG) analysis revealed that T3 displayed elevated levels of genes associated with extracellular matrix (ECM) remodeling pathways. Trajectory analysis indicated that T3 represented the most advanced differentiation stage as a subclone. Our findings provide insights into the dynamic spatial heterogeneity and metastatic progression of primary and metastatic TNBC tumor subtypes. Citation Format: Yu-Ting Kang, Tzu-Hung Hsiao. Spatial transcriptomics reveals clone-specific features of primary and metastatic tumors in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5313.