Figure 4.

Marker gene expression in human SK-N-BE(2) NB cells grown for 3 weeks as xenograft tumors in nude mice. (A) Hematoxylin/eosin (H&E)-stained section of a tumor, indicating areas analyzed in the experiments illustrated in this figure and Fig. and 5. Necrotic (*) and well vascularized (▵) areas are indicated. (B–D) In situ hybridization showing VEGF expression adjacent to a necrotic (*) area. C is a magnification of the framed area in B. D is a dark-field representation of B. (E–H) TH and IGF-2 expression in adjacent sections. G depicts a magnification of the framed area in E, and H is the dark-field representation of F. [Bars = 850 (A); 100 (B, D, and F–H); 25 (C); and 400 μm (E).]