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Evaluation of apoptotic parameters in normal and neoplastic human adrenal
G W Wolkersdörfer1, C Marx, J W Brown
1Department of Internal Medicine III, University of Leipzig, Germany.
Abstract:
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 apoptotic rates by the nonradioactive in situ end-labelling of DNA-fragments, immunohistochemistry against PCNA, CD95 and ultrastructural analysis. 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 adrenocortical neoplasms. MHC class II, which was previously shown to be involved in programmed cell death in lymphocyte populations (1), was detectable in normal and benign but not in malignant adrenocortical neoplastic cells. 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 malignant and benign neoplasms requires further markers.
Insights
Programmed cell death, or apoptosis, is higher in normal adrenal cortex than in tumors. Apoptosis analysis helps differentiate normal from neoplastic adrenal tissue, but not benign from malignant tumors.
Area of Science:
- Endocrinology
- Cell Biology
- Oncology
Background:
- Adrenocortical cell migration and proliferation involve programmed cell death.
- Understanding apoptosis in adrenal tissues is crucial for diagnosing neoplasms.
Purpose of the Study:
- To compare programmed cell death rates in normal and malignant adrenocortical tissues.
- To investigate the role of apoptosis in adrenal zonation and neoplasm differentiation.
Main Methods:
- Nonradioactive in situ end-labeling of DNA fragments to assess apoptotic rates.
- Immunohistochemistry for proliferating cell nuclear antigen (PCNA) and CD95.
- Ultrastructural analysis.
- Detection of MHC class II expression.
Main Results:
- The highest apoptotic labeling index (LI) was observed in the outermost zones of the normal adrenal cortex (average 20%).
- Adrenocortical neoplasms showed significantly lower apoptotic LI (average 2%).
- MHC class II was present in normal and benign adrenal cells but absent in malignant neoplasms.
Conclusions:
- Apoptosis analysis offers insights into normal adrenal zonation.
- Apoptosis rates can differentiate normal adrenal cortex from neoplasms.
- Distinguishing between benign and malignant adrenal neoplasms requires additional markers beyond apoptosis and MHC class II.