Table 1. Main differences observed between the cell-of-origin models and their derived tumor xenograft cell lines.

	Cell of origin model (MSC-5H)	model of tumor evolution (T-5H)
intra-tumor heterogeneity	low	increased
sphere forming ability*	+++ (small spheres)	+++ (large spheres)
selection of tumor initiating cells by tumorsphere culture*	+	+++
increase of ALDH1A1 in tumorspheres*	+	+++
increase of ALDH1A3 in tumorspheres*	+	+++
levels of ALDEFLUOR activity*	++	+++
increase of SOX2 in tumorspheres*	+	+++
increase in sphere forming ability in ALDHhigh cells*	n.a.	−
increase of tumorigenic properties in ALDHhigh cells*	n.a	++

(*) Relative level of increase in the indicated properties: (−): no differences; (+): small increase; (++): moderate increase; (+++): large increase; n.a.: not analyzed.