Figure 3.

Transplanted ^LBEGFR⁺ GBM Cells Are Robustly Tumor-Initiating In Vivo

(A) Intracranial xenotransplantation yields robust tumor growth and infiltration at 60 days in ^LBEGFR⁺DAPI^low populations only (1 × 10⁵).

(B) Quantification of proliferation (Ki67⁺) in human nuclear antigen (HNA⁺) glioma cells from ^LBEGFR⁺DAPI^low and EGFR⁻DAPI^low transplantations (^∗∗p = 0.001 at 2 months, ^∗p = 0.014 at 4–6 months) (n = 3 independent experiments).

(C) EGFR⁻DAPI^low (1 × 10⁵) glioma cells show no or minimal proliferation close to the needle track at 60 days (n = 3 tumors; example shown is the only one with minimal proliferation).

(D and E) ^LBEGFR⁺DAPI⁻ (0.5 × 10⁵) and EGFR⁻DAPI⁻ (1 × 10⁵) populations show only debris around the needle track surrounded by a GFAP⁺ astroglial scar at 60 days (representative examples of three independent tumors).

(F–H) Four to six months after injection, ^LBEGFR⁺DAPI^low (1 × 10⁵) transplants display large and diffusely infiltrative high-grade gliomas, (G) retain EGFR amplification status by chromogenic in situ hybridization, and (H) express EGFR as well as differentiating markers GFAP and TUJ1 (representative examples, n = 3 independent tumors for F–H).

Scale bars, 50 μm. Bar graphs show mean ± SEM.