The potential of stem cells in breast cancer therapy: A review.

Breast cancer remains the most prevalent malignancy among women worldwide, underscoring the urgent need for innovative therapeutic strategies. Stem cell-based anticancer approaches have attracted substantial attention because of their ability to generate immune-related cells and selectively home to tumor sites, among which mesenchymal stem cells (MSCs) are considered particularly promising owing to their strong tumor-tropic capacity and low immunogenicity. In this review, current evidence on the biological functions and therapeutic potential of MSCs and MSC-derived exosomes in breast cancer was systematically compiled and analyzed, with particular emphasis on MSC-mediated cytokine signaling, modulation of the tumor microenvironment, and the molecular cargo and functional effects of MSC-derived exosomes. The available data indicate that MSCs exert context-dependent dual effects, either promoting or inhibiting tumor growth through secretion of cytokines and activation of intercellular signaling pathways, while exosomes derived from MSCs likewise display both antitumor and protumor activities yet retain intrinsic tumor-targeting capability. Notably, compared with live MSCs, exosomes demonstrate greater stability, reduced immunogenic risk, and enhanced feasibility as therapeutic delivery vehicles, highlighting their translational potential. Accumulating evidence suggests that immune regulation and remodeling of the tumor microenvironment represent central mechanisms underlying these bidirectional effects. Collectively, MSCs and their derived exosomes constitute promising therapeutic platforms for breast cancer; however, their context-dependent regulatory properties necessitate rigorous mechanistic investigation and careful optimization prior to clinical application, and a deeper understanding of the molecular pathways through which they influence tumor progression will be essential for the development of safer and more effective stem cell-based anticancer therapies.