Targeting tumor neovasculature in non-small-cell lung cancer.

Recent insight into the molecular biology of cancer and mechanisms of tumorigenesis, has allowed for the identification of several potential molecular targets and the development of novel "targeted therapies". One of the most active research fields in NSCLC is the discovery of therapies that target angiogenesis. The vascular endothelial growth factor (VEGF) pathway represents a crucial component of the tumor angiogenesis process. Two different strategies have been developed in clinical practice in order to restrict tumor vasculature development; either the use of monoclonal antibodies against VEGF or small molecule tyrosine kinase inhibitors to target the tyrosine kinase domain of VEGF receptor. Among these agents that have been tested bevacizumab, a monoclonal antibody against VEGF, has been approved for the treatment of metastatic NSCLC in combination with chemotherapy, while several other agents are under phase III investigation. Moreover, several issues such as predictive biomarkers of response to antiangiogenic therapy and mechanisms of resistance to these agents remain to be elucidated. The purpose of this paper is to present the current status of antiangiogenic therapies in the treatment of NSCLC and to discuss these issues.