| [ Summary ] |
The mRNA expressions of cyclin A and p21/WAF1, which reguate cyclin-dependent kinase (Cdk2) activity positively and negatively, respectively, were evaluated in liver tissues obtained from patients with hepatocellular carcinoma (HCC). The expression of cyclin A mRNA was more frequently and strongly seen in cancerous tissues than in surrounding non-tumorous liver tissues. p21/WAF1 mRNA was ubiquitously expressed in liver tissues, however, the extent of its expression was weaker in the less-differentiated HCC. The intensity ratios of p21/WAF1 mRNA expression in cancerous tissues to that in non-tumorous liver tissues were 0.88±0.40 in patients with cyclin A mRNA-negative HCC(n=7), and 0.31±0.20 in those with cyclin A mRNA-positive HCC (n=7 ; p<0.01). It is suggested that reciprocal derangement of cyclin A and p21/WAF1 expressions may cooperatively induce accelerated proliferation of carcinoma cells, which in turn causes progression of HCC in conjunction with development of the dedifferentiation process. |