抄録
Telomeres are specialized chromosome end structures that contain highly repeated sequences, and shortening of these structures triggers cell senescence. Telomerase, which synthesizes telomere repeats, is inactive in most normal cells, but is activated in proliferating cells such as stem cells and tumor cells. The acquisition of telomerase activity is thought to be essential for the immortalization of cells. We measured telomere repeat length (TRL) and telomerase activity in human hepatocellular carcinomas (HCCs) and examined the contribution of changes in these parameters to hepato-carcinogenesis. Twenty HCC tissues and adjacent non-tumorous hepatic tissues resected perioperatively were analysed. Cellular DNA was extracted from tissues and TRL was measured by Southern blotting. The cell extract prepared from each tissue was used in a TRAP assay to determine the telomerase activity. Shortening of TRLs was found in 15 HCCs (75%), while TRLs were elongated in 5 HCCs (25%) . Telomerase activity was detected in 19 HCCs (95%), but in only one non-tumorous tissue (5 %) . No significant correlation was found between telomerase activity and the histological degree of differentiation of HCCs. Since most HCCs contained shortened telomeres, HCCs may develop from hyperplastic lesions where hepatic cells proliferate at a high frequency. Telomerase activity was detected almost exclusively in HCC tissues, and therefore could be useful for distinguishing HCCs from adenomatous hyperplasias and regenerative nodules, which are sometimes indistinguishable from HCCs.
