Drug resistance mechanisms of cancer stem-like cells and their therapeutic potential as drug targets.

Despite of recent advances in cancer research and development of new anti-cancer drugs, tumor patients' prognoses have not yet been improved well enough. Treatment failure of tumors is highly attributed to the drug resistance of a small population of cancer cell known as cancer stem-like cells (CSCs). CSCs also have the self-renewal activity and differentiation potency, conferring strong tumorigenicity on them. Therefore, development of CSC targeting therapy is urgently needed in order to overcome possible recurrence and metastasis by them after therapy. CSCs show some characteristic features that are not observed in other differentiated cancer cells, which give them higher resistance against conventional chemotherapy or radiotherapy. Targeting such specific features could be useful for CSC eradication. This review will summarize the recent advances in the study of CSC characteristics along with the promising therapeutic strategies targeting them.