Pericytes and vessel maturation during tumor angiogenesis and metastasis.

Despite promising results in preclinical and clinical studies, the therapeutic efficacy of antiangiogenic therapies has been restricted by a narrow focus on inhibiting the growth of endothelial cells. Other cell types in the tumor stroma are also critical to the progression of cancer, including mural cells. Mural cells are vascular support cells that range in phenotype from pericytes to vascular smooth muscle cells. Although the role of pericytes and pericyte-like cells in the pathophysiology of cancer is still unclear, evidence indicates that aberrations in pericyte-endothelial cell signaling networks could contribute to tumor angiogenesis and metastasis. The purpose of this review is to evaluate critically recent evidence on the role of pericytes in tumor biology and discuss potential therapeutic targets for anticancer intervention. (c) 2010 Wiley-Liss, Inc.