We determined, for the first time, the human telomerase reverse transcriptase (hTERT) mRNA expression, using real-time quantitative PCR, in liver tissues from patients with hepatocellular cancer (HCC; n = 13), chronic hepatitis B (n = 19) and C (n = 13). Liver tissues from the 45 patients and 17 patients without liver disease in whom liver biopsy was performed during cholecystectomy (control group), were investigated for telomerase activity (TA) and hTERT mRNA expression using the LightCycler technology. TA was detected in all HCC tissues compared with 15.6% of chronic hepatitis (P < 0.001) and none of controls (P < 0.001). TA levels and hTERT mRNA were higher in HCC compared with chronic hepatitis (P < 0.001) and normal livers (P < 0.001). hTERT mRNA expression was correlated with TA (P < 0.05). Chronic hepatitis patients who tested negative for TA and hTERT mRNA had significantly lower disease duration (58 +/- 85 months) compared with those tested positive (144 +/- 50 months; P < 0.05). Detection of TA and quantification of hTERT mRNA expression in liver tissues could be useful and additional markers for HCC diagnosis and may serve as prognostic markers for HCC development in chronic viral hepatitis patients. However, we were not able to draw general conclusions at this moment, as the number of chronic hepatitis patients positive for hTERT mRNA was relatively small. Real-time quantification of hTERT mRNA expression as a diagnostic/prognostic marker in patients with chronic hepatitis B and C and its relationship with hepatocarcinogenesis needs further evaluation.