Tumor formation after subcutaneous inoculation of ES or <i>in vitro</i> differentiated cells into various hosts.

ES cells and cells differentiated in vitro for 14 days were injected subcutaneously into the flank of syngeneic or allogeneic mice or xenogeneic rats (1×106 cells in PBS/animal). Some recipients received an immunosuppressive treatment with CsA (10 mg/kg/day). 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. 1in 2 mice (8%) a tumor regression was observed before day 100. 2in 2 mice (9%) a tumor regression was observed before day 100. 3in 1 mouse (7%) a tumor regression was observed before day 100. 4in 2 mice (11%) a tumor regression was observed before day 100. 5in 8 female mice (47%) a tumor regression was observed before day 100. 6in 2 rats (11%) a tumor regression was observed before day 100.