Originally discovered in endothelial cells [165,166] and initially thought to be found almost exclusively at the surfaces of endothelial and hematopoietic cells, Tie2 has recently received attention for its presence in the nonvascular compartments of gliomas, and its expression in neoplastic glial cells coincides with glioma progression from lower to higher grades [167,168]. Here, TEK is linked to glioma.