OBJECTIVE: The aim of this study was to determine the correlation between human 
adrenocortical carcinoma and the proteins involved in tumor angiogenesis, and to 
evaluate the angiogenic status of adrenocortical carcinoma.
METHODS: The expression of signal transducer and activator of transcription 3 
and insulin-like growth factor 2 as well as microvessel density was measured in 
a series of tissue samples from 44 human sporadic adrenocortical tumors by 
immunohistochemistry. These specimens were classified as adenomas (n = 20) and 
carcinomas (n = 24) according to the histological criteria defined by Weiss.
RESULTS: A total of 19 of 24 (79.17 %) malignant cases showed positive staining 
for signal transducer and activator of transcription 3 and 4 of 20 (20.00 %) 
benign cases showed positive, the difference of signal transducer and activator 
of transcription 3 expression between adrenocortical adenomas and adrenocortical 
carcinomas was statistically significant (P < 0.001). Similarly, insulin-like 
growth factor 2 staining was seen in 70.83 % (17/24) of the malignant cases 
versus 25.00 % (5/20) of the benign, the difference of insulin-like growth 
factor 2 expression among two groups was statistically significant (P = 0.002). 
Malignant cases showed higher microvessel density compared to benign tumors 
(84.70 ± 12.44 vs 21.05 ± 8.07, P < 0.001). Signal transducer and activator of 
transcription 3 and insulin-like growth factor 2 expression were positively 
correlated with microvessel density in all specimens (r_s = 0.832, P < 0.001; 
r_s = 0.703, P = 0.001).
CONCLUSIONS: This study has confirmed that adrenocortical carcinoma overexpress 
signal transducer and activator of transcription 3 and insulin-like growth 
factor 2; these results suggest that angiogenesis of human adrenocortical 
carcinoma may be mediated by these proteins and they could represent selective 
targets for the molecularly targeted treatments of adrenocortical carcinoma.