FIGURE 1.

Stem cell and CSC downhill model (inspired by Waddington’s epigenetic landscape) showing cell fate plasticity. (A) A stem cell goes through several steps to become differentiated cells (like a ball going downhill). The differentiated cells can be reprogrammed back into a pluripotent state (like hill climbing) or into different lineage cells. (B) CSCs are capable of self-renewal and generation of differentiated progeny (like downhill). CSCs may arise from stem cells, progenitor cells, or differentiated cells. (C) Increasing evidences indicated the cell fate plasticity between CSCs and non-CSCs. These conversions are dependent on epigenetic regulation, gene expression patterns, as well as interactions with microenvironment.