VASCULAR ENDOTHELIAL GROWTH-FACTOR (VEGF) EXPRESSION IN PROSTATIC TUMORS AND ITS RELATIONSHIP TO NEUROENDOCRINE CELLS

Vascular endothelial growth factor (VEGF) expression was examined by i mmunohistochemistry in 45 prostatic carcinoma specimens and ten benign prostatic tumours (BPH). The majority of carcinoma specimens exhibite d cytoplasmic staining for VEGF and showed a trend of increasing expre ssion with dedifferentiation (2p=0.003). Immunoreactive VEGF was also seen in the prostatic carcinoma cell lines, the order of staining inte nsity was PC3>DU145>LNCaP. Intense granular cytoplasmic staining for V EGF was observed in neuroendocrine-like cells which were seen focally in many of the prostatic specimens. Consecutive sections were incubate d with a chromogranin A antibody to confirm the neuroendocrine phenoty pe of these cells. A significant correlation (P<0.0001) between the to tal number of intensely stained VEGF-positive cells and chromogranin A -positive cells was found. A subpopulation of neuroendocrine-like cell s also showed intense immunoreactivity for transforming growth factor alpha (TGF-alpha). A correlation was observed (2p=0.0092) between the intensity of VEGF and TGF-alpha immunostaining in carcinoma cells whic h were not of neuroendocrine differentiation. The presence of these tw o angiogenic factors may aid the neovascularisation of carcinomas and their increased expression in tumour-associated neuroendocrine cells m ay contribute to a more aggressive phenotype.