VCAM-1 is expressed on both the apical and the basolateral surfaces of endothelial cells in vivo.

Cryostat sections of NQ22 masses at their initial SC growth were fixed in acetone–methanol and stained with anti VCAM-1 mAb M/K-2 and visualized with fluorescein-conjugated goat antimouse IgG. (A) Detail of the 2-dimensional reconstruction. (B) Detail of the tridimensional reconstruction of a series of sections taken in 0.13-μm steps through a tissue section in which 2 blood vessels are clearly evident.