TRANSCRIPTION FACTOR ADRENAL-4 BINDING-PROTEIN AS A MARKER OF ADRENOCORTICAL MALIGNANCY

Adrenal 4 binding protein (Ad4BP) is a transcription factor that regul ates the expression of the steroidogenic enzymes and is expressed prim arily in steroidogenic cells. We immunolocalized Ad4BP in adrenocortic al carcinoma (eight cases) and various malignancies that histologicall y simulate an adrenocortical carcinoma to evaluate the value of Ad4BP as an immunohistochemical marker of adrenocortical carcinoma, These ma lignancies examined were renal cell carcinoma (20 cases), hepatocellul ar carcinoma (10 cases), malignant melanoma (eight cases), ovarian (si x cases) and uterine (three cases) clear cell carcinoma, large cell ca rcinoma of the lung (five cases), and pheochromocytoma (three cases), Nuclear Ad4BP immunoreactivity was observed only in adrenocortical car cinoma cases but not in other tumors examined. Almost all of the adren ocortical carcinoma cells were immunohistochemically positive for Ad4B P including cells associated with bizarre nuclei. These results show t hat application of Ad4BP immunostain can contribute greatly to the dif ferential diagnosis of adrenocortical carcinoma. Copyright (C) 1995 by W.B. Saunders Company