HPP-CFC, detected first at early somite stages (E8.25) in mouse yolk sac and ES cells-derived EBs, is the earliest multipotential hematopoietic precursors that can be cultured in vitro in the absence of stromal cells.

• 80%25 Smad5-/-HPP-CFC能产生次级HPP-Mix，而仅有20%25的野生型HPP-CFC能产生此类集落。 Smad5-/-HPP-CFC的细胞表型和分子表型是吻合的。