EPOCH cells are phenotypically heterogeneous. (A) To generate EPOCH cells, iCdx4 ESC differentiated in the presence of doxycycline (day 3 to day 6 of differentiation) were infected with retroviral MSCV-HoxB4-IRES-GFP and expanded on OP9 stroma with cytokines for 10 days before transplantation into irradiated Rag-2^−/−γc^−/− mice. (B) EPOCH cells expanded on OP9 stroma for 10 days were analyzed by flow cytometry for the expression of cell surface markers previously shown to be relevant to HSC biology (c-Kit, CD41, CD45, CD34, CD48, and CD150). Data presented are the summary of at least 3 independent experiments. (C) CD41, CD45, and c-Kit expression on surface of EPOCH cells is shown.