Roles of pleiotrophin in tumor growth and angiogenesis.

Pleiotrophin (PTN) is a heparin-binding growth factor with diverse biological activities, the most studied of these being those related to the nervous system, tumor growth and angiogenesis. Although interest in the involvement of PTN in tumor growth is increasing, many questions remain unanswered, particularly concerning the receptors and the signaling pathways involved. In this review, we briefly introduce PTN, and summarize data on its involvement in tumor growth and angiogenesis, and on what is known to date concerning the receptors and pathways involved.