Fig 5. MYCN Expressing Progenitors Do Not Form Tumors.

(A) Tumors derived from subcutaneously injected BE (2)-C cells showed neuroblastoma-like histologic features including dense cellularity, high nuclear-to-cytoplasmic ratios, high mitotic activity, and frequent apoptotic bodies. Scale bar equals 100 microns. (B) BE (2)-C derived tumors showed diffuse nuclear expression of PHOX2B and (C) diffuse cytoplasmic TH expression. Scale bars equal 100 microns. (D) While human neuroblastoma cells formed tumors in 6/7 mice, MYCN overexpressing adrenal progenitor cells did not form tumors (0/7). Average tumor volumes are shown. 5 x 10⁴ BE (2)-C human neuroblastoma cells or cells dissociated from Mycn-infected primary spheres were resuspended in HBSS with 30% Matrigel and delivered subcutaneously to nude mice.