The role of tumor microenvironment and signaling pathways in regulating breast cancer stem cells: Implications for therapy resistance and tumor recurrence.

Breast cancer stem cells (BCSCs) are recognized as a critical subpopulation involved in cancer recurrence and metastasis, as they are capable of self-renewal and differentiate into various cell types. BCSCs play significant roles in tumor progression, being regulated by key signaling pathways such as Notch, PI3K/AKT/mTOR, and Hedgehog, and their interactions with the tumor microenvironment, which affect tumor growth and resistance to therapeutics. This review focuses on the surface markers of BCSCs, their roles in recurrence and metastasis, and the key signaling pathways. It also discusses the recent progress in understanding how BCSCs contribute to drug resistance and explores potential therapeutic strategies targeting these cells and their microenvironment to improve clinical outcomes and prevent relapse.