[The significance of Ki-67 antigen expression in the distinction between benign and malignant pheochromocytomas].
OBJECTIVE
To investigate the expression of Ki-67 antigen in benign and malignant pheochromocytomas, and to evaluate whether the expression of Ki-67 antigen could serve as a diagnostic marker for predicting the biological behaviour of these tumors.


METHODS
Ki-67 antigen were detected by immunohistochemical technique and image analysis in 57 cases of clinically documented benign and malignant pheochromocytomas were analyzed. Aside from histological study, Ki-67 immunohistochemistry studies were performed to get the Ki-67 index. Statistical analysis was performed between these groups.


RESULTS
Ki-67 index was low in benign pheochromocytomas (average 0.98%), and high in malignant pheochromocytomas (average 3.78%). There was statistically significant difference in expressions of Ki-67 antigen between benign and malignant pheochromocytomas. The Ki-67 index of 2 cases in benign pheochromocytomas (5.1%, 2/39) and 10 cases in malignant pheochromocytomas (55.6%, 10/18) was higher than 3%. The accuracy, sensitivity, specificity, positive predictive value and negative predictive value of Ki-67 index higher than 3% to diagnosis malignant pheochromocytomas was 82.5%, 55.6%, 94.9%, 83.3% and 82.2%. The follow-ups indicated the survival rate of patients with higher Ki-67 index was lower than those with lower Ki-67 index.


CONCLUSIONS
Ki-67 may serve as a useful marker of the biological behavior of tumors, and can provide useful information for prognosis of tumor patients. Immunohistochemical assessment of Ki-67 antigen can be useful in the differential diagnosis of malignant from benign pheochromocytomas. Ki-67 index (> 3%) is a useful marker for distinguishing benign from malignant tumors or for predicting the malignant potential of pheochromocytomas.
Feng
Chao
C
Department of Urology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
Li
Han-Zhong
HZ
Yan
Wei-Gang
WG
Gao
Jian-Gang
JG
Xu
Wei-Feng
WF
Luo
Yu-Feng
YF
Cao
Jin-Ling
JL
D000293:Adolescent; D000310:Adrenal Gland Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D010673:Pheochromocytoma / Q000175:diagnosis* / Q000378:metabolism; D012680:Sensitivity and Specificity
D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen