Telomerase activity in adrenal cortical tumors and pheochromocytomas with reference to clinicopathologic features

Telomeres consist of short repeated sequences that are shortened on continuous cell proliferations and synthesized by telomerase, an RNA-dependent DNA polymerase. Recent molecular studies have reported that telomerase is activated in most human cancers, whereas it is not detected in most somatic cells. These findings indicate that the positive telomerase 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 malignant potential using conventional histopathologic examination. To determine whether telomerase activity is useful as a diagnostic marker, we examined telomerase activity in adrenal cortical tumors and pheochromocytomas with special reference to their clinicopathologic features. Using a highly sensitive polymerase chain reaction (PCR)-based detection method, telomerase activity was demonstrated in one of 13 adrenal cortical tumors and two of seven pheochromocytomas, whereas all seven normal portions of adrenal gland failed to showed any telomerase activity. Although none of the tumors examined in this study was associated with metastasis, these three telomerase-positive tumors were accompanied by clinicopathologic features suggesting malignant potential. Telomerase activity might be a potential marker for estimating the biologic characteristics of adrenal cortical tumors and pheochromocytomas.