Expression of vascular endothelial growth factor (VEGF) and association with microvessel density in small-cell and non-small-cell lung carcinomas

Abstract

Recent studies have demonstrated that tumor angiogenesis is a prognostic factor for various malignant neoplasms. Specifically, in non-small-cell lung carcinomas (NSCLCs) most reports show an association between neovascularization and vascular endothelial growth factor (VEGF) expression as well as the presence of metastases and survival, although a few reports do not agree with these findings. Angiogenesis is not clearly characterized in small-cell lung carcinomas (SCLCs), since they are rarely treated by surgery, and thus the available tissue for biological characterization is sparse. The aim of the present study was to investigate angiogenesis and the expression of VEGF in lung tumors. We examined 88 non-small-cell and 39 smallcell lung carcinomas. Angiogenesis was estimated by determining microvessel counts, with the use of anti- CD31 and anti-factor VIII antibodies and expression of VEGF was also evaluated immunohistochemically. Our data showed that in NSCLCs angiogenesis was more prominent in poorly-differentiated neoplasms and correlated with VEGF expression, therefore it is at least in part mediated by the latter. Interestingly, in SCLCs a higher vascularization was noted. However, there was no strong association with VEGF expression. Thus, smallcell lung carcinoma may represent a suitable neoplasm for testing antiangiogenic drugs in combination with chemotherapy. Nevertheless, antiangiogenic therapy should not be targeted specifically to the VEGF pathway, since in SCLCs other mediators of angiogenesis may be important as well.