Self-renewal and the capacity to differentiate into a multitude of mature cell types have made stem cells the hottest ticket in biomedicine. But there are questions aplenty, scientific and otherwise.
- Do we need more stem cell lines? President Bush may believe that the available lines are sufficient, but these are derived fro1m blastocysts produced in fertility clinics. Maximizing the impact of stem cells in medicine calls for new lines derived from specific diseases, like cancers.
- Must therapeutic cloning be used to generate new lines? Yes, transplanting nuclei from cells of adults with genetic disorders into enucleated eggs--therapeutic cloning--provides the obvious route to study disease development. In the longer term this approach could also provide genetically matched tissues for transplantation.
- Is transdifferentiation real? After five frantic years, current thinking hovers between "maybe" and "probably." While promising, most scientists do not (yet) consider transdifferentiation to be a replacement for therapeutic cloning....