Elevated levels of telomerase activity in malignant pheochromocytoma.
BACKGROUND
Although malignant pheochromocytoma is a life-threatening illness, there is no excretory profile that is predictive of malignancy. Reliable prediction of malignant behavior on the basis of histopathology is also notoriously difficult. Although DNA ploidy can be a helpful indicator, aneuploidy per se is not considered to be a specific marker of malignancy. Mutations in p53 have been reported to occur frequently in cases of benign pheochromocytoma. Thus, molecular analysis of this protein is not a useful diagnostic tool. The authors analyzed telomerase activity in benign and malignant pheochromocytomas and assessed its utility as a prognostic marker.


METHODS
Telomerase activity was estimated in 16 benign pheochromocytomas, 3 malignant pheochromocytomas, and 16 normal adrenal medullae by the fluorescence-based telomeric repeat amplification protocol. The telomerase activities of each group of samples were compared.


RESULTS
No telomerase activity was detected in any of the normal adrenal medullae or the benign pheochromocytomas. By contrast, all of the three malignant pheochromocytomas had elevated telomerase activity. The telomerase activity in each tumor was determined to be 87.6 units, 71.2 units, and 180.3 units, respectively.


CONCLUSIONS
The expression of telomerase activity in pheochromocytoma clearly suggests the malignant behavior of the component cells. Analysis of telomerase activity appears to be a powerful tool for the diagnosis of malignant pheochromocytoma.
Kubota
Y
Y
Department of Urology, Yamagata University School of Medicine, Japan.
Nakada
T
T
Sasagawa
I
I
Yanai
H
H
Itoh
K
K
D000310:Adrenal Gland Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology / Q000601:surgery; D000313:Adrenal Medulla / Q000201:enzymology; D000782:Aneuploidy; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics; D001794:Blood Pressure; D002395:Catecholamines / Q000097:blood / Q000652:urine; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D005453:Fluorescence; D005500:Follow-Up Studies; D005544:Forecasting; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D010673:Pheochromocytoma / Q000201:enzymology* / Q000235:genetics / Q000473:pathology / Q000601:surgery; D011003:Ploidies; D015203:Reproducibility of Results; D015996:Survival Rate; D019098:Telomerase / Q000032:analysis* / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000032:analysis / Q000235:genetics
D014408:Biomarkers, Tumor; D002395:Catecholamines; D004273:DNA, Neoplasm; D016159:Tumor Suppressor Protein p53; D019098:Telomerase