Selective ex vivo expansion of megakaryocyte precursors by relatively simple protocols including SCF, TPO and IL-3[22], or SCF and TPO only[21], showed no clinical benefit on thrombocytopenia reduction when compared to unmanipulated PBSC alone when administered as an adjunct to unmanipulated autologous PBSC. This evidence concerns the gene TPO and Thrombocytopenia.