Expressions Of Three Factors Associated With The Ubiquitin-mediated Proteolysis Of The P27 Protein In Human Hepatocarcinogenesis

Objective: To investigate the expressions and correlations of three factors associated with the ubiquitin-mediated proteolysis of the p27 protein in human hepatocarcinogenesis, and to identify the molecular mechanism of hepatocarcinogenesis. Methods: By using immunohistochemistry, Cyclin E, Skp2 and Ubiquitin proteins were evaluated in the tissues of chronic hepatitis, liver cirrhosis, paratumor cirrhosis, HCC, and normal liver tissues (80 sample, totally). And the expressions of the three proteins were quantitatively measured by using Image Analysis System. Results: Mainly Cyclin E and Ubiquitin proteins locate in nucleus. There were two staining patters in the expression of Skp2 protein. One was nuclear staining patterns in HCC and chronic hepatitis, another was cytoplasmic staining in liver cirrhosis and paratumor cirrhosis. In nucleus, the expressions of these proteins were the highest in HCC, and proteins levels were noted to be higher in else groups (P<0.05). And from normal liver tissues, liver cirrhosis, paratumor cirrhosis to HCC, the expressions of Cyclin E and Skp2 protein were gradually increased. Respectively, in the four groups the means of Positive Unit were 20.8, 22.8, 27.5 and 48.6 (Cyclin E); 15.8, 23.7, 29.5 and 48.2 (Skp2). In HCC, the Cyclin E protein expression was positively correlated with histological grade (r=0.4468, P<0.05). Furthermore, in chromic hepatitis, the expressions of Cyclin E, Skp2 and Ubquitin proteins were only lower than those in HCC, and there were significant...