ABSTRACT
The report of the derivation of the first human embryonic stem cell (hESC) lines1 represented a revolutionary discovery, since its biological characteristics were both enormously promising therapeutically and heralded important regulatory challenges. hESCs are derived from the inner cell mass (ICM) of embryos cultured to the morula or blastocyst stage. Their most significant properties are their robust proliferative capacity for self-renewal and their pluripotency, by which they are capable of differentiating into virtually any cell type under the right conditions. These unique characteristics of hESCs make them suitable for future application in humans, as their lines may constitute an unlimited source of all cell types to be used in cell-based regenerative medicine therapies, and also in human developmental studies, tissue engineering, in-vitro gene therapy models2 and as a screening tool for the pharmaceutical industry.
