Interaction between regulatory T cells and cancer stem cells.

The concept that cancer stem cells (CSCs)/tumor stem cells/cancer-initiating cells are one of the key centers to cure neoplastic disease has drawn an increasing attention recent years. Because of their high resistance and potential to initiate tumors, CSCs are considered a critical factor associated with tumor relapse. Regulatory T(T(reg)) cells, a group of immune cells with tumor-promoting effect, exert their function through inhibition of effector T cells and regulation of the tumor microenvironment by producing a series of soluble factors. However, the interactions between T(reg)s and CSCs are less understood. The mechanisms of how T(reg)s, as tumor-promoting cells, manipulate CSCs remain obscure. In this review, we elucidate their interactions.