Different immunohistochemical patterns of TGF-beta1 expression in benign and malignant adrenocortical tumours.

OBJECTIVE: Transforming growth-factor beta1 (TGF-beta1) influences a number of specific functions of adrenocortical cells in several animal species. The aim of our study was to evaluate by immunohistochemical analysis the presence and distribution of TGF-beta1 in normal adrenal tissue and in different adrenal tumours. PATIENTS: We analysed 8 functioning (5 adenomas and 3 carcinomas) and 15 non functioning (6 adenomas and 9 carcinomas) adrenal tumours and 6 normal adrenal glands. RESULTS: In normal adrenal glands, the glomerulosa and the reticularis zones displayed diffuse cytoplasmic staining, while the fasciculata zone was almost completely negative. Functioning adenomas displayed cytoplasmic staining restricted to compact cells while in nonfunctioning adenomas, prevalently composed by clear cells, no staining was observed. Overall, adrenal carcinomas were characterized by the lack of cytoplasmic positivity and by sporadic positive cells around vessels both in functioning and in nonfunctioning tumours. CONCLUSIONS: TGF-beta1 expression is associated with active steroid secretion in normal adrenal tissue, as well as in benign cortical adenomas, while this relationship is lost in primary adrenal malignancies. These data provide indirect evidence for a regulatory role played by TGF-beta1 on steroid secretory pathways.