TELOMERASE ACTIVITY IN ADRENAL-CORTICAL TUMORS AND PHEOCHROMOCYTOMAS WITH REFERENCE TO CLINICOPATHOLOGICAL FEATURES

Telomeres consist of short repeated sequences that are shortened on co ntinuous cell proliferations and synthesized by telomerase, an RNA-dep endent DNA polymerase. Recent molecular studies have reported that tel omerase is activated in most human cancers, whereas it is not detected in most somatic cells. These findings indicate that the positive telo merase activity is closely related to the malignant potential of human tumors. In several types of human tumors, including adrenal cortical tumors and pheochromocytomas, it is very difficult to predict the mali gnant potential using conventional histopathologic examination. To det ermine whether telomerase activity is useful as a diagnostic marker, w e examined telomerase activity in adrenal cortical tumors and pheochro mocytomas with special reference to their clinicopathologic features. Using a highly sensitive polymerase chain reaction (PCR)-based detecti on method, telomerase activity was demonstrated in one of 13 adrenal c ortical tumors and two of seven pheochromocytomas, whereas all seven n ormal portions of adrenal gland failed to showed any telomerase activi ty. Although none of the tumors examined in this study was associated with metastasis, these three telomerase-positive tumors were accompani ed by clinicopathologic features suggesting malignant potential. Telom erase activity might be a potential marker for estimating the biologic characteristics of adrenal cortical tumors and pheochromocytomas.