Abstract

A tumor consists of not only cancer cells but also an ecosystem including different subpopulations. Cancer stem cells (CSCs) are a rare subpopulation in the tumor cell population. Traditional therapies, such as chemotherapy and radiotherapy target cancer cells except for CSCs. Therefore, the self-renewal and colony formation capacity of CSCs provides the recurrence of tumors as well as drug resistance. Different strategies are used to eradicate CSCs with the knowledge of CSC properties. The recent technologic revolution gives a chance to design nanoscale medicines for the effective treatment of CSCs. Nanoparticle-based delivery systems improve the transport of traditional therapeutic drugs across biological barriers with maximum bioavailability, less toxicity, and side effects, and take advantage in combination with specific CSC targets, controlled and site-specific release. This chapter summarizes the current models of CSCs, the molecular mechanisms leading to metastases and drug resistance of CSCs, strategies to target CSCs, examples of currently approved nanomedicine drugs and future perspectives.