Expression of telomerase-associated protein 1 and telomerase reverse transcriptase in hepatocellular carcinoma

To know whether two protein components of human telomerase (human telomeras e-associated protein 1 (hTEP1) and human telomerase reverse transcriptase ( hTERT) are useful markers for telomerase activation in human liver diseases , we examined mRNA levels of these and telomerase activity in human liver s amples. Twenty-three human hepatocellular carcinomas (HCCs) and correspondi ng adjacent livers were analysed for hTEP1 and hTERT expression by semiquan titative reverse transcription-polymerase chain reaction, and for telomeras e activity by a telomeric repeat amplification protocol assay. Thirteen liv er samples (ten HCCs and three dysplastic nodules) that were biopsied with 21-gauge needles were analysed for hTERT expression, hTEP1 was expressed in all samples examined. No correlation between hTEP1 expression and telomera se activity was observed, hTERT expression significantly correlated with te lomerase activity (P < 0.001). The positivity of hTERT for HCC and correspo nding non-cancerous liver was 100% and 30.4% respectively (P < 0.001). Seve nty four per cent (17/23) of HCCs showed strong hTERT expression, but none of the non-cancerous liver tissues did. hTERT expression of the 21-gauge ne edle biopsied specimens showed no significant difference from that of the s urgical samples. The present study revealed that hTERT is strongly expresse d in most HCCs, and that hTERT but not hTEP1 is a key component regulating telomerase activity in human liver. (C) 2000 Cancer Research Campaign.