Embryonic stem cell-derived neural progenitors as non-tumorigenic source for dopaminergic neurons

Table 1 Tumor formation after subcutaneous injection of mouse neuronal progenitor cells in comparison to mouse embryonic stem cells and neuronal cells differentiated in vitro from mES cells

	SCID/beige	LOU/c + CsA
MNP	0% (0/9)	0% (0/9)
mES cells	93% (13/14)	0% (0/25)
Neuronal cells differentiated from mES cells	94% (17/18)	61% (11/18)

1 × 10⁶ mouse neuronal progenitor (MNP), mouse embryonic stem (mES) cells (MPI-II)[4] or neuronal cells differentiated in vitro for 14 d from the mES cells (> 95% beta-III tubulin -positive)[4] were injected subcutaneously into the flank of SCID/beige mice or LOU/c rats treated with CsA (10 mg/kg per day). The percentage and number of animals is indicated in which tumors were found during autopsy at the site of injection 3 mo following injection.

Table 2 Tumor formation after subcutaneous injection of human neural progenitor cells in comparison to human embryonic stem cells

	SCID/beige
HNP1 p9, 1 x 106	0% (0/6)
HNP1 p19, 2 x 106	0% (0/3)
HNP4 p10, 1 x 106	0% (0/3)
HNP4 p21, 2 x 106	0% (0/9)
hES cells (H9)	75% (3/4)

1 or 2 × 10⁶ human neural progenitor cells (HNP1 or HNP4) at passages 9 or 10 and 19 or 21, respectively, and 1 × 10⁶ human embryonic stem (hES) cells (H9) were injected subcutaneously into the flank of SCID/beige mice. The percentage and number of animals is indicated in which tumors were found during autopsy at the site of injection 6 mo (HNP1 and HNP4) or 3 mo (hES cells H9) following injection.