Vascular endothelial growth factor expression is reduced in liver metastasis from colorectal cancer and correlates with urokinase-type plasminogen activator.

We undertook a retrospective study to investigate the correlation between the expression of vascular endothelial growth factor (VEGF) and urokinase-type plasminogen activator (u-PA) proteins with progression of colorectal carcinoma (CRC). Immunohistochemical analyses using antibodies against VEGF and u-PA were carried out on archival specimens of 58 human colon carcinomas, 30 liver secondaries and 20 adenomas. Expression of VEGF was significantly reduced in the metastatic liver tumours compared with primary ones (Wilcoxon test, P = 0.002), suggesting VEGF activity to be secondarily down-regulated once the tumour cells reach the hepatic parenchyma. There was no strong evidence from our data that the level of VEGF or u-PA in the primary tumour could predict risk of liver metastasis or survival duration. VEGF and u-PA expression were positively correlated in primary CRC suggesting that both proteins may interact in vivo (chi-square test, P = 0.019) in tumour progression.