Prognostic value of vascular endothelial growth factor expression in patients with lung cancer: a systematic review with meta-analysis.

Vascular endothelial growth factor (VEGF) has been implicated in tumorigenesis and metastasis, and it presumably mediates the proliferation of endothelial cells and promotes vascular permeability. However, the prognostic value of VEGF overexpression in patients with lung cancer remains controversial.