Expression of urokinase-type plasminogen activator (u-PA), u-PA receptor, and tissue-type PA messenger RNAs in human hepatocellular carcinoma.

Expression of plasminogen activators (PAs) and urokinase-type PA receptor (u-PAR) is associated with tumor growth and invasion. For in vivo human tumor tissues, there is no information on gene expression of PAs in hepatocellular carcinoma (HCC) or other hepatic pathophysiological conditions. In this study we examined the relative levels of u-PA, tissue-type PA (t-PA), and u-PAR mRNA expression in human HCC by reverse transcription-PCR compared with those expressed in peritumoral hepatic tissues. Twenty-five of 25 HCCs expressed u-PA mRNA, as well as 16 of 25 hepatic peritumoral tissues. However, none of the 14 cases of nontumorous liver samples (i.e., normal parenchyma, steatosis, and nonspecific reactive and chronic hepatitis) showed detectable levels of u-PA mRNA. The same samples analyzed for uPAR and t-PA mRNAs exhibited higher levels of these mRNAs in the malignant tissues compared with nontumorous ones. A strong correlation was found between the relative levels of u-PA and t-PA mRNAs detected in the tumor and in the corresponding peritumoral tissues (P < 0.001 for u-PA; P < 0.02 for t-PA). However, there was no correlation between the expression of u-PA and t-PA in HCC (P = 0.565). Furthermore, a significant inverse correlation was found between survival months of male patients and the relative level of u-PA mRNA (P < 0.05) detected at the time of biopsy, whereas no correlation was found in the case of t-PA mRNA. These results are in line with the possible differential biological role of u-PA and t-PA in the tumor etiopathogenesis and suggest that the detection of relative levels of u-PA mRNA may be a useful prognostic factor for male HCC patients.