Role of urokinase in colorectal neoplasia

The biofunctional activity of the plasminogen activators urokinase and tissue plasminogen activator has been measured in extracts from 50 colorectal carcinomas and 21 adenomas using a bioimmunoassay. Compared with control mucosa urokinase activity was significantly elevated in adenomas (P less than 0.001) and carcinomas, levels being significantly higher in carcinomas (P less than 0.05). In contrast tissue plasminogen activator activity was reduced in adenomas (P less than 0.01) and carcinomas, levels being significantly lower in carcinomas (P less than 0.01). Although enzyme activity did not relate to Dukes' stage or histological grade urokinase activity was higher in carcinomas with venous invasion (n = 17, P less than 0.05), in those with moderate or extensive local spread (n = 27, P less than 0.05) and in cases where a palliative resection only was feasible because of advanced disease (n = 8, P less than 0.05). Urokinase has been implicated in tissue degradation as well as fibrinolysis and may play a role in tumour invasion and metastasis in human colorectal neoplasia.