BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common malignant tumours worldwide. Telomerase is reactivated in various types of malignant tumors and may contribute to the development of HCC. To evaluate the role of telomerase in formation and development of HCC, we analyzed its expression status in different parts of HCC tissues and peripheral blood mononuclear cells (PBMCs), and explored its clinical implications for diagnosis of HCC.
METHODS: Total RNAs and telomerase were extracted from HCC and their non-cancerous tissues, and both relationships were analyzed between them. The expression of telomerase reverse transcriptase (hTERT) mRNA and telomerase activities in liver tissues and PBMCs were detected by RT-PCR and telomeric repeat amplification protocol (TRAP)-ELISA, respectively. The diagnostic values of telomerase in PBMCs were investigated in the diagnosis and differentiation of HCC.
RESULTS: The specific activities of telomerase were 18.25±15.02 A/μg RNA in HCC tissues, and significantly higher than those in their non-cancerous tissues (8.16±6.22 A/μg RNA, P<0.05). But total RNA levels in HCC were 12.40±7.34 μg/mg wet liver and lower than 53.77±52.02 μg/mg wet liver in their non-cancerous parts (P<0.01). The different telomerase levels could be detected in PBMCs from patients with chronic liver diseases and control group. The enzyme activities were significantly higher in HCC than in any other groups (P<0.01). However, circulating telomerase levels were more obviously decreased in HCC patients after transcatheter arterial embolization treatment than before the treatment (P<0.01). The analysis of combined serum alpha-fetoprotein level and PBMCs telome-rase was more sensitive and specific for the diagnosis of HCC.
CONCLUSION: The abnormal expression of telomerase in HCC tissues and circulating PBMCs could be a useful marker to the diagnosis and prognosis of HCC.