Tie receptors: new modulators of angiogenic and lymphangiogenic responses.

Angiogenesis is required for normal embryonic vascular development and aberrant angiogenesis contributes to several diseases, including cancer, diabetes and tissue ischaemia. What are the molecular mechanisms that regulate this important process? The Tie family of receptors and their ligands, the angiopoietins, are beginning to provide insight into how vessels make decisions such as whether to grow or regress--processes that are important not only during development but throughout an organism's life.