MET and neoplasm: This indicates a weak basal c-Met expression in accordance with the CSC theory, which states that not all, but only a small sub-population within the tumor mass has tumorigenic potential.22 Because our former results suggest that a tumorigenic population is enriched in spheroidal cultures, we compared the expression of c-Met in adherent- and anchorage-independent growing stromal cells of the eight GCTB-derived specimens by FACS analysis.