Frequent expression of the vascular endothelial growth factor in human non-small-cell lung cancers

Background: Angiogenesis is an essential factor for progression and metastases in solid tumors. It has been reported that several angiogenic factors play a role in the regulation of angiogenesis. Vascular endothelial growth factor (VEGF) is one of the most important molecules in angiogenesis, We investigated expressions of VEGF in a series of lung carcinomas with regard to clinicopathological factors. Method: VEGF expression was investigated by use of immunohistochemical studies and Northern blot analysis, using 155 primary and 26 metastatic lung carcinomas for the immunohistochemical studies and 10 primary and two metastatic lung carcinomas for the Northern blot analysis. All lesions were resected at surgery. Results: The frequencies for positive VEGF expression were 64 of 74 (86.5%) adenocarcinomas, 38 of 67 (56.7%) squamous cell carcinomas, four of four (100%) large cell carcinomas, two of three (66.7%) adenosquamous carcinomas and one of five (20%) small-cell carcinomas, the degree of positivity generally being greater in well differentiated tumors, The majority of metastatic foci from adenocarcinomas and squamous cell carcinomas at other sites were also positive (76.5 and 66.7%, respectively). VEGF expression did not correlate with clinicopathological factors such as tumor size or pathological stage, but pathological stage adenocarcinoma cases positive for VEGF demonstrated a shorter disease-free period when followed up for 48 months than those cases expressing VEGF negatively. Conclusions: The results indicated that VEGF expression was frequently detected in non-small-cell lung cancers and suggested that VEGF might relate to the disease-free period of the patients with early adenocarcinomas.