Expression of STAT3 and IGF2 in adrenocortical carcinoma and its relationship with angiogenesis.

ABSTRACT

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.