Genetic manipulation of human embryonic stem cells: a system to study early human development and potential therapeutic applications.

The successful derivation of human embryonic stem cell (hESC) lines by Thomson and colleagues [Thomson et al., 1998] provided a new area of investigation in both regenerative medicine and early human development. Fundamental study of the molecular and cellular mechanisms responsible for normal lineage development will rely on reproducible protocols to direct the differentiation of hESCs into specific lineages of interest and genetically manipulate both hESCs and their derivatives. Identifying standards for maintenance of hESCs, methods for controlled differentiation and genetic manipulation of hESCs and their derivatives will provide a foundation to explore their potential therapeutic use in cell and gene therapy. In the present review, our goal is to outline the latest advances in the field with particular focus on how hESCs and their derivatives can be genetically altered, how this may be useful in better understanding the cellular and molecular events of lineage differentiation, and how deregulation of these cellular processes may lead to abnormal development and disease.