[A study of gene amplification and expression of cyclin D1 in hepatocellular carcinoma].

OBJECTIVE: To investigate gene amplification of CCND1 and expression of cyclin D1 in hepatocellular carcinoma (HCC) and to explore the possible relationship between CCND1 gene status and carcinogenesis of HCC. METHODS: Differential PCR, RT-PCR and immunohistochemistry were used to detect gene amplification, mRNA and protein expression of cyclin D1 in 20 HCC cases respectively. The relationship between the gene amplification rate and the expression level of cyclin D1 and the histological grades of HCC was analyzed. RESULTS: CCND1 gene amplification was detected in 30% of the cases HCC. An overexpression of cyclin D1 mRNA and protein could be demonstrated in 45% and 70% cases respectively. The expression of cyclin D1 mRNA correlated with its gene amplification status (P < 0.05) and was responsible for the protein expression level (P < 0.05). There was a close relationship between the expression level of cyclin D1 protein and HCC histological grades (P < 0.05). CONCLUSIONS: CCND1 gene amplification is a common phenomenon in HCC and may be directly responsible for the cyclin D1 mRNA and protein overexpression. Cyclin D1 protein expression level is directly related to HCC histological grades. Therefore, CCND1 amplification and cyclin D1 overexpression may play an important role in development and differentiation of HCC.