The number of cells positively expressing SCA1 remained relatively stable as passage number increased. A decrease in the hematopoietic stem cell marker CD45 was observed as cell passage increased. Also, an increase of expression of the stem cell marker SSEA4 between low- and high-passaged cells occurred. Expression of MHC Class I remained relatively stable between low- and high-passaged cells, but a decrease in MHC Class II was observed between low- and high-passaged cells, respectively. MHC, major histological complex; SSEA4, stage specific embryonic antigen 4.