Dr. Landis began by thanking attendees on behalf of the NIH Stem Cell Task Force. She noted that the intent of this symposium is to provide concrete examples of state-of-the-art stem cell-based therapies. She noted that there are numerous types of stem cells, which originate in varied tissues. Moreover, there is no single "best" stem cell for all applications; rather, a wide range of options is available. As such, the clinical applications of stem cells vary in their maturity; some cell-based therapies have been proven in clinical trials while others are still being investigated in the laboratory. She noted that although this symposium focuses on therapy, this aspect represents only a small portion of the wealth of information that stem cells are providing on the molecular and cellular processes that regulate development and differentiation.