A Few to Flip the Angiogenic Switch

摘要

The rapid formation of blood vessels, a process known as the angiogenic switch, is required for progression of dormant or micrometastatic tumors to macrometastatic invasive tumors. New blood vessels may either sprout from preexisting mature ones or form de novo by recruiting circulating endothelial progenitor cells derived from the bone marrow. Although these progenitors can incorporate into human tumors and transplanted tissue , they do so in small numbers, raising doubt about their physiological contribution to neo-angiogenic processes. On page 195 of this issue, Gao et al.