Figure 1
From: Cancer stem cells – the current status of an old concept: literature review and clinical approaches
Two features defining cancer stem cells. A – Self-renewal: the ability to generate descendants retaining stemness characteristics. Stem cells undergo symmetric division to give two stem cells or asymmetric division, where one descendant remains a stem cell, whereas the other cell loses stemness features. B - Restoration of the heterogeneous cancer cell population. The secondary tumour is composed of the same cell types as the primary tumour.