EVALUATION OF APOPTOTIC PARAMETERS IN NORMAL AND NEOPLASTIC HUMAN ADRENAL

The migration and proliferation of adrenocortical cells is accompanied by mechanisms of cellular knock-out. We compared the programmed cell death of normal and malignant adrenocortical tissues on the basis of a poptotic rates by the nonradioactive in situ end-labeling of DNA-fragm ents, immunohistochemistry against PCNA, CD95 and ultrastructural anal ysis. The highest labelling index (LI) was detectable in the outermost zones of the adrenal cortex of normal adrenals. Average LI in normal. adrenal cortex was 20% whereas only 2% was detectable in adrenocortic al neoplasms. MHC class II, which was previously shown to be involved in programmed cell death in lymphocyte populations (I), was detectable in normal and benign but not in malignant adrenocortical neoplastic c ells. In conclusion, the analysis of apoptosis provides new aspects of normal adrenal zonation and allows the differentiation between normal and neoplastic adrenal cortex although the differentiation between ma lignant and benign neoplasms requires further markers.