Investigating Endothelial Precursor Cells (EPCs)

Overview

Recent studies suggest that cells in the bone marrow-endothelial precursor cells (EPCs)-can provide a blood supply to cancerous tumors. The purpose of this study is to collect brain tumor and blood samples to look for these EPCs in the samples and analyze the growth signals that may help blood vessels to grow in tumors. Researchers will study the following in the samples: 1) the number of blood vessels in the tumor; 2) the levels of growth factors in the tumor and blood; 3) the levels of circulating EPCs in the blood; and 4) the changes in the genes and proteins in the blood and tumor that influence growth factor levels. Participants will be 18 years of age or older and have evidence of a brain tumor that requires surgery. From this surgery they will donate blood and tumor samples. Participants will have follow-up visits 4 to 8 weeks after surgery, then at 3-month intervals for two-and-one-half years, then at 6-month intervals thereafter. At these visits, participants will undergo a physical exam, a brain scan, and blood work.

Angiogenesis, or the development of new blood vessels, appears to be one of the keys to tumor survival. Areas of new blood vessel growth, or neovascularization, such as with trauma or tissue ischemia, appear to release factors that stimulate production of endothelial cells from progenitor stem cells located in the bone marrow. Endothelial cells for the inside lining of blood vessels are important in the formation of viable and functional blood vessel conduits. Recent work suggests that tumors-including primary brain tumors-secrete many of the same stimulatory growth factors as normally incite endothelial cells to be produced and turned out into the circulation. Initial evidence suggests that these circulating endothelial progenitor cells (EPCs) play a role in the impressive neovascularization seen with tumors. In this study, we wish to investigate the interaction of gliomas and EPCs to elucidate a potential role for EPCs in tumor formation, response to therapy, progression, and overall survival, as well, to identify potential new targets for anti-tumor and/or anti-angiogenic therapies using genomic and proteomic techniques. Patients suspected of having, or with prior biopsy proof of, a WHO grade II-IV central nervous system (CNS) glial tumor(s) seen in the Surgical Neurology Branch, NINDS, will be considered for entry into this study. Tissue samples of tumor resected as part of standard care will be collected at surgery and preserved for research. Blood samples will also be collected. Blood will also be collected from anonymous normal volunteers who donate blood at the NIH Blood Bank; these anonymous donors will serve as controls.