Correlates of urokinase-type plasminogen activator in colorectal cancer: positive relationship with nm23 and c-erbB-2 protein expression.

We undertook a study to analyze the expression of urokinase-type plasminogen activator (u-PA) protein in colorectal cancer (CRC) and to compare it with c-erbB-2 (HER2/neu) and nm23 protein expression. Paraffin-embedded specimens from 58 patients with CRC were retrospectively collected. Immunohistochemical staining of u-PA, c-erbB-2, and nm23 was quantitatively evaluated using a color video image analysis (color VIA) technique. No correlation was found between u-PA expression and tumor stage, age, sex, or tumor site. Although there was no evidence from our data that the level of u-PA in the primary tumors could predict risk of liver metastasis or survival duration, CRC showing overexpression of u-PA (above 85 pixels) had a worse prognosis (P = 0.013). There were significant positive correlations among all three u-PA, c-erbB-2, and nm23 proteins (u-PA vs. c-erbB-2, P = 0.003; u-PA vs. nm23, P < 0.001; c-erbB-2 vs. nm23, P = 0.001), suggesting that, in vivo, all proteins interact or are similarly regulated.