Figure 3.

CD95^high GBM cells display superior self-renewal in vitro and are highly tumorigenic in vivo. (a–e) Sphere formation by FACS-sorted CD95^high and CD95^neg cells freshly isolated from five patient tumor samples plated at 500 cells per well (t-test). (f) Representative gating strategy for cell sorting. (g–i) Sphere formation by CD95^high and CD95^neg cells freshly isolated from three tumor samples plated under limiting-dilution conditions. Estimated stem cell frequencies: (L) CD95^neg: 1 : 110, CD95^high: 1 : 1 (limiting dilution not reached); (M) CD95^neg: 1 : 771, CD95^high: 1 : 163; (N) CD95^neg: 1 : 122, CD95^high: 1 : 30. (j) 1 × 10³ unsorted, CD95^neg or CD95^high cells were injected into the striatum of Fox Chase SCID beige mice (n=5 for unsorted and CD95^neg, n=6 for CD95^high). (k) Tumor growth was monitored by T2-weighted MRI. (l) Tumor volumes at the end of the MRI observation period 22 weeks after injection (ANOVA). (m) Kaplan–Meier curve showing the survival of the animals after the MRI observation period. In accordance with the observed tumor growth, CD95^high-injected animals show the highest mortality