MaGSC Stra8 SSC5 cells cultured under various conditions (I to IV) and cells differentiated in vitro for 5 plus 10 days (diff.) were injected subcutaneously into the flank of SCID/beige mice (2 × 106 cells in PBS/animal). The percentage and number of animals in which tumors were found during autopsy or in which tumors were palpable (at least during 3 consecutive observations) at the side of injection before day 100 after injection is indicated. In addition, the percentages and numbers of animals are given in which tumors were present but regressed before day 100 and in which an invasive growth was observed. The differentiated cells (diff.) were obtained as described in the Materials and Methods section from maGSC Stra8 SSC5 cells that had been cultured under condition III.