Figure 7.

Immunostaining of a normal (+/+) and a β1-null (−/−) teratoma for the expression of vWF and for β1 integrin expression. Teratomas were removed 21 d after inoculation and sectioned. Neighboring sections were stained for vWF and β1 integrin expression, respectively. Whereas normal teratomas have large vessels, β1-null teratomas have small vessels. Note that like in normal tumors vessels of β1-null tumors coexpress vWF and β1 integrin indicating that endothelial cells are host derived. Bar, 100 μm.