Exosomal lncRNAs as molecular switches driving macrophage-tumor co-evolution in breast cancer.

Breast cancer progression is increasingly recognized as a dynamic process shaped by reciprocal communication between malignant cells and the tumor microenvironment (TME). Among immune-cell populations, tumor-associated macrophages (TAMs) are major regulators of immune suppression, metabolic adaptation, angiogenesis, and therapeutic resistance. Emerging evidence indicates that extracellular vesicle (EV)-mediated transfer of long non-coding RNAs (lncRNAs) constitutes an important mechanism underlying tumor-immune communication in breast cancer. In this review, we summarize mechanistically characterized studies examining how exosomal lncRNAs regulate bidirectional signaling between breast cancer cells and macrophages and contribute to tumor progression, immune remodeling, and resistance-associated phenotypes. Tumor-derived exosomal lncRNAs modulate macrophage signaling through pathways associated with signal transducer and activator of transcription 3 (STAT3), transforming growth factor beta (TGF-β), Hippo/Yes-associated protein (YAP), hypoxia-responsive signaling, and autophagy-related remodeling, thereby promoting immunoregulatory and tumor-supportive macrophage phenotypes. Conversely, macrophage-derived exosomal lncRNAs, including hypoxia-inducible factor-1 alpha (HIF-1α)-stabilizing long non-coding RNA (HISLA), reinforce glycolytic adaptation, epithelial-mesenchymal transition, epigenetic remodeling, metastatic plasticity, and resistance to therapy in recipient tumor cells. Exosomal lncRNA signaling additionally influences γδ T cells, endothelial cells, and stromal compartments, supporting broader multicellular regulation within the TME. Collectively, current evidence supports exosomal lncRNAs as biologically important mediators of tumor-immune adaptation in breast cancer. We further discuss the translational potential of circulating exosomal lncRNAs as minimally invasive biomarkers and evaluate therapeutic strategies targeting EV biogenesis, vesicle trafficking, and oncogenic lncRNA cargo molecules. Finally, we highlight current limitations involving EV heterogeneity, lncRNA stoichiometry, and incomplete in vivo validation that remain critical barriers to clinical translation.