Plasticity of bone marrow-derived stem cells.

Recently, concepts for the transplantation of hematopoietic stem cells have changed dramatically. High-dose myeloablative conditioning regimens are in the process of being replaced by immuno-suppressive regimens, ablating host myelopoiesis, and neoplastic cells by the co-transplanted donor lymphocytes. Furthermore, the presence of stem cells in the bone marrow, capable of differentiating into a variety of nonhematopoietic tissues as well as the presence of cells in other organs, capable of differentiating into hematopoietic cells, has led to the novel concept of the plasticity of stem cells derived from different tissues. It is anticipated that these remarkable studies will also lead to novel therapeutic strategies.