Vascular endothelial growth factor gene and protein: strong expression in thyroiditis and thyroid carcinoma

Angiogenesis is implicated in several pathological conditions, such as infl ammation and tumor growth. Vascular endothelial growth factor (VEGF), also known as vascular permeability factor, is a potent;stimulator of endothelia l cell proliferation in vitro and in vivo. The present work aimed to compar e VEGF expression in human normal thyroid glands, thyroiditis tissue and th yroid carcinomas using immunohistochemistry and in situ hybridization (ISH) . Both chronic lymphocytic thyroiditis and differentiated thyroid carcinoma s were found to strongly express VEGF mRNA and encode larger amounts of VEG F than normal thyroid tissue as attested by a VEGF immunostaining score. In addition, tumor samples from patients with metastases showed a higher immu nostaining score than their non-metastatic counterparts (P<0.05). Carcinoma s with the greatest contents of VEGF mRNA and VEGF protein had the most int ense mitogenic activity. Special focus on endothelial cells she-wed intense mitogenic activity in neoplastic tissues in contrast to the total quiescen ce of endothelial cells in non-tumoral tissues. An intense VEGF production by differentiated thyroid carcinoma, attested either by a higher immunostai ning score or a strong VEGF mRNA expression using ISH, could be a promising marker of tumor aggressiveness and may also be useful as a predictor of me tastatic potential.