It is widely believed that tumor angiogenesis and cancer growth critically depend on circulating endothelial precursor cells, mobilized from the bone marrow. The recent study from researchers at the University of Helsinki, Finland, and Stanford University, US, now suggests that a stem cell type supposed to be crucial for blood vessel formation and cancer growth does not actually exist.
Angiogenesis, the growth of new blood vessels, is a central process in diverse physiological and pathological situations such as healing of wounds and traumas, cardiovascular disorders, inflammatory conditions such as rheumatoid arthritis, and in cancer growth. The current belief about the source of blood vessel wall endothelial cells (ECs) responsible for vascular growth in adults is that a significant and crucial part of neovascular ECs originate from circulating stem and progenitor cells that are first mobilized from the bone marrow (BM), and subsequently differentiate to mature bona fide ECs and incorporate in the vasculature. This concept has become textbook material, and a common theme in modem vascular and cancer biology.
Importantly, it is widely believed that tumor angiogenesis and cancer growth critically depend on BM derived circulating endothelial precursor cells. Endothelial precursors would thus provide a powerful novel approach to block tumor angiogenesis and cure cancer. Correspondingly, therapeutic transplantation of such stem cells would be a promising approach to restore tissue vascularization after ischemic events. Clinical trials with human patients are currently ongoing based on the circulating endothelial precursor cell dogma.