ABSTRACT
Acknowledgments ............................................................................................ 420
References ........................................................................................................ 420
We have recently discovered unprecedented heterogeneity in the molecular
composition of endothelial cells by profiling the vasculature using in vivo phage
display. It is now apparent that each tissue expresses its own specific set of cell
surface proteins on vascular endothelial cells. In addition, many pathological
conditions, including tumors, diabetes, atherosclerosis, and inflammatory diseases,
add their disease-specific tags to the endothelium of the affected tissues. During
tumor progression, many vascular changes are involved in the process of
angiogenesis as tumors are not able to grow without a blood supply.1 Besides
inducing angiogenesis i.e., sprouting of new blood vessels from existing vessels,
tumors also co-opt existing blood vessels.2 These tumor-induced changes have
already started taking place at the stage of premalignant lesions.1 In addition to
the blood vasculature, tumors contain lymphatic vessels and many tumors induce the
growth of lymphatic vessels, lymphangiogenesis. The presence of lymphatic vessels
seems not to be essential for tumor growth. However, lymphatics have been shown
to act as an important route for the metastatic spread of tumors to both regional and
distant lymph nodes.3
