VEGF-A immunohistochemical and mRNA expression in tissues and its serum levels in potentially malignant oral lesions and oral squamous cell carcinomas

Abstract

The aim of the study was to investigate whether the estimation of circulating Vascular endothelial growth factor-A (VEGF-A) levels by ELISA could be used as surrogate of VEGF-A expression in tissues of pre-malignant oral lesions (PMOLs) and oral squamous cell carcinoma (OSCC) as compared to that in healthy controls. The study samples comprised of tissue and blood samples from 60 PMOLs, 60 OSCC, and 20 healthy controls. Serum VEGF-A levels were determined by an ELISA based assay (Quantikine human VEGF; R & D System, Minneapolis USA). Tissue VEGF-A expression and microvessel density (MVD) were assessed by immunohistochemistry (IHC) using antibodies against VEGF-A and CD-34 on formalin fixed paraffin embedded (FFPE) tissue sections. VEGF-A mRNA expression was analyzed by real-time PCR in snap frozen tissues. Serum VEGF-A levels and immunohistochemical VEGF-A expression were significantly high in PMOLs and OSCC in comparison with controls. VEGF mRNA gene expression showed more than 50-fold increase in PMOLs and OSCC. VEGF-A levels in serum correlated in a linear fashion with the tissue expression in oral pre-malignant and malignant lesions, suggesting that the serum levels may serve as surrogate material for tissue expression of VEGF-A.