Monitoring of circulating angiogenic factors in dendritic cell-based cancer immunotherapy

BACKGROUND A promising treatment approach for patients with malignant disease that recently has found its way into clinical trials is based on vaccination with autologous dendritic cells loaded with tumor antigens. However, adequate assays for monitoring clinical and immunologic responses still are under debate. In recent years, the determination of angiogenic markers has shown considerable potential in the diagnosis and prognosis of patients with malignant disease, because tumor growth and spread are promoted by angiogenesis, the formation of new blood vessels. METHODS The authors established a method for measuring the plasma levels of three modulators of angiogenesis: vascular endothelial growth factor, platelet-derived endothelial cell growth factor, and thrombospondin-1. The angiogenic blood profile of a healthy control group was characterized and compared with a group of patients with malignant disease. Ultimately, levels of circulating angiogenic factors were monitored in the course of dendritic cell–based cancer immunotherapy. RESULTS Baseline levels of angiogenic mediators varied substantially among healthy individuals but showed consistent values for each individual. Blood levels of circulating angiogenic factors were elevated significantly in patients with advanced disease and were highly sensitive to dendritic cell–based immunotherapy. CONCLUSIONS To our knowledge, the current report was the first to analyze circulating levels of angiogenic factors during dendritic cell–based immunotherapy. The authors observed a noteworthy change in the angiogenic blood profile with treatment, and this change was correlated with the induction of an immunologic response. Cancer 2003. © 2003 American Cancer Society.