In fact cancer stem cells were discovered back in the late 1990s by Dr. John Dick M.D. and colleagues and then in early 2000s it was shown with breast cancer stem cells taken from a patient and transplanted into immunodeficient mice, that the cancer stem cells give rise to the very same tumor. That was done by Dr. Wicha M.D. and Dr. Michael Clarke PhD .
Cancer stem cells and not mutations give rise to cancer. So what is the stimulus? That is the question.