Cancer

Existence of cancer stem cells was first demonstrated by Dr. John Dick's group in 1997, and since then cancer stem cells have been found in breast, brain, and colon. Are the cancer stem cells the key targets for cancer therapy? Can cancer stem cells be targeted specifically without affecting normal stem cells? Moreover, given mounting evidence suggesting that cancer stem cells share properties with normal stem cells, will regenerative medicine that uses embryonic stem cells increase the cancer risk of patients?