Fig. 2.

Ephrin-B2 is preferentially expressed in the blood vessels of MDA-MB-435 tumor xenografts. Mouse and human ephrin-B2 were simultaneously PCR-amplified from tumors derived from mixed populations of MDA-MB-435 cells (lanes 1 and 2) or clonal cells expressing EphB4ΔC-EGFP (lanes 3 and 4) or EGFP-F (lanes 5 and 6). The control PCR products were from mouse P1 brain (m) and cultured mixed populations of MDA-MB-435 cells (h). Digestion with a restriction enzyme that recognizes only the mouse ephrin-B2 shows that in the tumors ephrin-B2 was amplified predominantly from mouse cells. Digestion with a human-specific enzyme confirmed this conclusion (data not shown).