Reduction of telomeric repeats as a possible predictor for development of hepatocellular carcinoma: convenient evaluation by slot-blot analysis.

Hepatocellular carcinoma (HCC) mainly arises from the liver with chronic inflammation. Because telomere reduction reflects replicative history in somatic cells, we analyzed the possibility that liver tissues surrounding HCC consist of the cells carrying substantial reduction of telomere. We studied 20 HCC and surrounding noncancerous liver tissues (SL) obtained by surgical resection, and 10 laparoscopically obtained needle biopsy specimens of the liver with chronic inflammation including no overt HCC (CI). Five liver tissues without chronic liver diseases (ND) were also examined. Extracted genomic DNAs were blotted on a nylon membrane, and probed at first with radio-labeled d(TTAGGG)(3) and reprobed with radio-labeled d(CCT)(7). The intensity caused by d(TTAGGG)(3) was divided by that of d(CCT)(7). The ratio was defined as telomeric repeats content (TC). Dilution experiments reproducibly revealed almost the same TC. The reduction rate of telomere length through aging estimated by regression analysis of TC was 0.62% per year. Concomitant analyses of TC and average telomere length revealed that both values were significantly correlated (r =.45; P =.009). To compare TC in the liver with respect to chronic inflammation, the value was divided by TC in peripheral blood leukocytes (PBL) from the same donor. The ratio was defined as relative TC (RTC). There was a statistically significant decrease of RTC in CI compared with that in ND (P =.03). Furthermore, RTC in SL was significantly lower than that in CI (P =.0001). These observations suggest that RTC value in liver tissues may digitally indicate a replicative history of hepatocytes under chronic inflammation, and a risk of HCC development.