ADULT STEM CELLS

August 2004
		Adult stem cells, which come from bone marrow, skin, brain, blood and muscle, appear to have enormous potential to help repair the body. But individual studies on stem cell therapy are showing mixed results. Helen Blau, Ph.D., of the Stanford University School of Medicine and Charles Murry, M.D., Ph.D., of the University of Washington's Department of Pathology answer your questions.

Online NewsHour Special Report: Adult Stem Cells Forum Introduction If the current restrictions posed on stem cell research were eliminated, how long would it be before initial procedures for spinal cord injuries would begin to appear? I have Parkinson's and I'm 51 years old. What's a possible timetable for the application of stem cell therapy to help me and others in my age range? Why can't stem cells derived from bone marrow be cultured and the injected locally into regions of the brain that has been damaged as a consequence of a stroke? What are your feelings on the potential of umbilical cord blood as a source of stem cell transplantation? Is it true that the research to date is not applicable to all ethnic groups, particularly, persons of African decent? Can stem cells injected into the body cause cancers? What kind of research is happening in this country, and when can I see human research here?	Bill Peacock of Auckland, New Zealand, asks: Can stem cells injected into the body cause cancers? Dr. Charles Murry responds: Causing a tumor is the most feared complication of any stem cell-based therapy. Embryonic stem cells, if injected in an undifferentiated state and not given proper guidance, will form a tumor in virtually any location. We will need to be very careful to control the differentiation of these cells if we hope to harness them for tissue regeneration. Adult stem cells are much less likely to form tumors because their ability to become multiple cell types is much more limited. There is, to some extent, a trade off between the potential of a stem cell to regenerate tissues and the risk of tumor formation. Dr. Helen Blau responds: No. There is no evidence to date that cancer is caused by adult bone marrow derived stem cells. After injection, no cancer is observed for the entire course of a mouse's life.