This PDF analysis looks at challenges and advances for the next 15 years of tissue engineering, as seen by scientists in the field: "highly strategic issues often may not lie at the forefront of our day-to-day conception of the most important foci in the field, making such analyses more important to undertake. For example, the strategically most important category, angiogenic control [or engineering blood vessels], was supported by only four contributed ideas. However, its dominance over nine other concepts and its low level of present progress propelled it to the top of the list of strategic concepts. Clearly, mastering the control of angiogenesis will be at the heart of any attempts to grow larger tissue engineered constructs than have thus far been achievable. This will apply whether such growth occurs in vitro or within the body as a response to cell and/or scaffold implantation. Stem cell science is the second most strategic concept. [It] may well be that the understanding and control of stem cell development will enable us to short circuit some of the tissue engineering methods used heretofore - perhaps allowing the concurrent growth of vascular systems with parenchymal tissues."