Combined expression of urokinase-type plasminogen activator and proliferating cell nuclear antigen at the deepest invasive portion correlates with colorectal cancer prognosis.

To examine the relationship among the expression of urokinase-type plasminogen activator (u-PA), invasive/metastatic potential and prognosis of colorectal cancer (CRC), 58 patients with surgically resected advanced CRC were studied. u-PA expression and proliferating cell nuclear antigen labeling index (PCNA-LI) at the deepest invasive portion were examined immunohistochemically. u-PA expression was detected in 37 (63.8%) of 58 lesions. Lesions with liver metastasis showed a significantly (p < 0.01) higher incidence of u-PA expression than those without liver metastasis. Dukes staging also revealed a significant correlation with u-PA expression. The combination of u-PA expression and elevated PCNA-LI at the deepest invasive portion correlated significantly with prognosis. These results indicate that u-PA expression is an important predictor of CRC development and liver metastasis. Furthermore, combined analysis of u-PA expression and PCNA-LI at the deepest invasive portion is very useful in predicting CRC prognosis.