Cancer stem cell research: current situation and problems.

The concept of a "cancer stem cell system" that continues to supply cancer component cells has been proposed. It is time to apply stem cell studies, which is a field of expertise in regenerative medicine, to cancer treatment. Cancer treatments that effectively attack cancer stem cells acting as a manufacturing plant for producing differentiated cancer progenies will be designed by revealing the cancer stem cell system. Therefore, in the near future we hope that revolution will occur in cancer therapy to eradicate cancer and prevent the recurrence thereof. In this review we discuss the current situation and problems of cancer stem cell research.