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Fibroblast growth factors and early hemopoietic cell development.

The role of fibroblast growth factors (FGFs) in the regulation of the human hematopoiesis is controversial. Older publications suggest that FGFs play an important role in regulating the proliferation of human hematopoietic progenitor and stem cells. Such studies should be interpreted with caution because they were typically carried out in the presence of serum which not only contains significant amounts of FGFs, but other cytokines as well. The development of greatly improved techniques for isolating purified populations of primitive hematopoietic cells, for culturing such cells in serum free conditions, and for analyzing the molecular consequences of exposing these cells to FGF cytokines allow the conclusions of these earlier studies to be tested more rigorously. Our investigations, and those of others, suggest that FGFs may not play an important direct role in regulating the development of human hematopoietic stem cells. These data, and our view of their implications, are discussed in this review.