Spotlight on circulating tumor cells

As has been proven, cancer does not simply consist of one type of cell; rather tumors can be made up of a heterogeneous collection of cells with varying phenotypes. It has been proposed that only a small subpopulation of the cells making up a tumor hold any tumorigenic potential – namely cancer stem cells (CSCs). The CSC model proposes that these cells renew and sustain the tumor in a background of nontumorigenic cells, driving therapy resistance, recurrence and enabling metastatic spread.