Cross-talk between cancer-initiating cells and immune cells: considerations for combination therapies

Cancer initiating cells (CIC) or cancer stem-like cells (CSC) represent a small, distinct population of cancer cells best characterized by their high tumorigenicity. They undergo asymmetric cell division that results in repopulation of the bulk of the tumor and self-renewal. CICs are likely responsible for treatment failure and tumor recurrence, as they are highly resistant to traditional therapies, such as chemo- and radiotherapy (1). This resistance is partly due to their proliferative quiescence and increased anti-apoptotic features. Immune targeting is an emerging alternative approach, which may override these resistance mechanisms. However, relatively little is known about the interaction between CICs and immune cells that have the capacity to recognise and destroy not only the bulk of the tumor but also CICs