Fig. 3
From: Molecular mechanisms of tumor resistance to radiotherapy
The mechanisms by which cancer stem cells generate radioresistance. This diagram shows how CSCs can self-renew upon differentiation, become quiescent, be involved in tumorigenesis, and generate immunosuppressive signals as well as exert possible effects of DNA damage repair, low ROS levels, apoptosis, autophagy, and epithelial–mesenchymal transitions in tumor stem cell–associated radioresistance. In addition, several active signaling pathways (e.g., Wnt Notch Hedgehog TGF-ß PI3K/AKT/mTOR) may also be closely related to tumor stem cell radioresistance. EMT: epithelial–mesenchymal transition, ROS: reactive oxygen species, TGF-β: transforming growth factor-β, PD-L1: programmed cell death ligand 1, IL-10: interleukin 10, Bcl-2: B-cell lymphoma-2