Stem cell engineering: the new generation of cellular therapeutics.

Hematopoietic stem cells (HSCs) supply all blood cells throughout life by making use of their self-renewal and multilineage differentiation capabilities. Over the last few years, transplantation of hematopoietic stem and progenitor cells from mobilized blood stem cells, umbilical cord blood and selected CD34+ cells has been used for treatment of patients with hematologic and non-hematologic malignances. The techniques have become available that allow the extensive proliferation, orderly differentiation, functional activation and gene transfer of hematopoietic stem/progenitor cells in ex vivo culture systems. These techniques have now developed to the point at which clinical trials are now underway in a variety of settings for the applications of hematopoietic stem cell transplantation, hematopoietic support after high-dose chemotherapy, immunotherapy of cancers, and gene therapy. The article will discuss the characteristics, detecting assays, surface markers, expansion, orderly differentiation, cell therapy and gene therapy of hematopoietic stem/progenitor cells. Except that, it will also discuss some advanced achievements of stem cell research, such as the multilineage differentiation of marrow-derived mesenchymal stem cells. Some results of different gene expression between stem cells and induced cells by gene chip analysis will be reported.