Figure 3 |. Fighting fire with fire.

a | Current T cell-based immunotherapies predominantly transfer cells with effector memory (T_EM)-like phenotypic and functional characteristics. These cells have limited self-renewal capacity and are oligopotent. These cells can mediate tumour destruction but are handicapped to compete with expanding tumour masses (shown as purple tumour cells) that are sustained by the activity of self-renewing multipotent cancer stem cells (CSCs; shown as dark purple tumour cells). b | Future T cell-based immunotherapies might benefit from the transfer of T memory stem cells (T_SCM) that have enhanced self-renewal and the multipotent capacity to form all memory and effector subsets. These properties allow T_SCM cells to sustain a prolonged immune attack by giving rise to more differentiated, highly lytic effector T (T_EFF) and T_EM cells while maintaining a continuous supply of less differentiated T_SCM and central memory (T_CM) cells that can refresh the pool of cytotoxic T cells over time. In this manner, T_SCM cells might overtake the last tumour cell, including CSCs, and so cure the host.