AuthOr’s VIew AuthOr’s VIew

During the last decade, the identification of cancer stem cells (CSCs) in various human malignancies1–3 led to substan-tial research efforts aimed at developing approaches to eliminate this small but crit-ical subpopulation of tumor cells.4 Once it became evident that CSCs are resistant to major conventional therapeutic strate-gies,5 it has been postulated that they play a key role in both local tumor recurrence and systemic relapse. Studies focused on targeting the molecular pathways that are selectively activated in CSCs have recently provided promising results.6 Harnessing the potency and specificity of the host immune response to eradicate CSCs represents an attractive approach. However, its feasibility is unknown. Most studies focusing on CSCs are based on the inoculation of human-derived CSCs into severely immunocompromised hosts. These xenograft tumor models offer many advantages, but preclude immunological assessments. Furthermore, most current forms of cancer immunotherapy, such as dendritic cell (DC)-based vaccines or the adoptive transfer of tumor-reactive T cells, are designed to target tumor-associated antigens expressed by the bulk of “differ-entiated ” cancer cells. The ability of these approaches to target CSCs is unclear. To circumvent these limitations, we used two syngeneic tumor models established in Targeting cancer stem cells via dendritic-cell vaccinatio