Surface marker expression on developing EBs. (A) Flow cytometric analyses of different aged EBs showing expression patterns of KDR, CD117, CD31, and CD34. (B) Coexpression of KDR, CD31, and CD117 on a subpopulation of day-8 EBs. Shaded histogram represents population stained with anti-CD117 antibody; open histogram is unstained control. (C) Hematopoietic progenitor potential of the presorted population (PS), and the CD31−KDR− (NEG), CD31−KDR+ (KDR), and CD31+KDR+ (KDR/CD31) fractions isolated from day-8 EBs.