Figure 1.

An overview of the origin of cancer stem cells (CSCs): CSCs can originate and develop from several cells. Normal stem cells may become CSCs through mutations, or it can develop into progenitor cells which in turn can develop into CSCs via mutations. In addition, progenitor cells can grow into CSCs through mutations and become a differentiated cell, which in turn can becomes undifferentiated and grow into CSCs. Moreover, CSCs can develop from dedifferentiated somatic cells or from cancer cells that undergo epithelial to mesenchymal transition (EMT).