Acquisition Order of Ras and p53 Gene Alterations Defines Distinct Adrenocortical Tumor Phenotypes
Epidermal growth factor (EGF) receptors were examined immunohistochemically in 64 adrenocortical carcinomas obtained at autopsy, and in 23 adrenocortical adenomas and seven pheochromocytomas obtained during surgery. In the nonneoplastic adrenal gland, EGF receptors were scattered to the zona glomerulosa, zona fasciculata, and zona reticularis. Adrenocortical carcinomas (63 of 64), more than adrenocortical adenomas (10 of 23) or pheochromocytomas (four of seven), stained positively for EGF receptors (P less than .01). The immunoreactivity was limited to the cytoplasm, cell membrane, and chromatin. When the antibody was immunoabsorbed with an excess of immunogen peptide, there was no evidence of immunostaining. The adrenocortical carcinomas could be classified into 16 cases of the well-differentiated type, 33 cases of the moderately differentiated type, and 15 cases of the poorly differentiated type. There was no relationship between histologic grading and staining intensity of the EGF receptors. On the other hand, more than 80% of the cases of adrenocortical carcinomas revealed a moderate to high intensity for EGF receptors. In 62 of the 64 patients, there was already metastases to other organs. We conclude that the expression of EGF receptors is associated with tumor growth and/or metastatic potential in adrenocortical carcinoma.