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Angiomyolipomas: the nature and expression of the HMB45 antigen
1Department of Pathology, Pennsylvania State University, College of Medicine, Hershey.
Abstract:
Fifteen cases of angiomyolipoma (AML) were studied by the immunoperoxidase method to investigate the nature of the HMB45 antigen and to determine if the antigen that stains with HMB45 in AML is the same HMB45 antigen that stains melanoma cells. Other antibodies utilized to accomplish this study included vimentin, cytokeratin, S-100 protein, and muscle actin (HHF-35). Large interstitial cells of AML regularly react with two different sources of HMB45 and are often positive for vimentin. The HMB45 reactivity of both antibodies is abolished by pretreating the tissue with neuraminidase. The same cells are not immunoreactive with cytokeratin or S-100 protein. A subpopulation of cells in AML demonstrates coexpression of HMB45 and muscle-specific antigen by double-immunolabeling techniques. These results suggest that the AML antigen that reacts with HMB45 is the same antigen present in melanocytic/melanoma cells and that a pluripotent cell, which generates a divergent range of differentiation, may be involved in the genesis of AMLs.
Insights
Angiomyolipoma (AML) cells share the HMB45 antigen with melanoma cells, suggesting a common origin. This finding points to a pluripotent cell potentially involved in the development of angiomyolipomas.
Area of Science:
- Immunohistochemistry
- Pathology
- Cell Biology
Background:
- Angiomyolipoma (AML) is a benign tumor with complex cellular composition.
- The HMB45 antigen is a marker typically associated with melanocytic and melanoma cells.
- The cellular origin and differentiation pathways of AML remain incompletely understood.
Purpose of the Study:
- To investigate the immunophenotype of angiomyolipoma cells.
- To determine if the HMB45 antigen in AML is identical to that found in melanoma.
- To explore the potential cellular origin of AML.
Main Methods:
- Immunoperoxidase staining was performed on 15 AML cases.
- Antibodies used included HMB45, vimentin, cytokeratin, S-100 protein, and muscle actin (HHF-35).
- Neuraminidase pretreatment and double-immunolabeling techniques were employed.
Main Results:
- Large interstitial cells in AML consistently reacted with HMB45 and vimentin.
- HMB45 reactivity was abolished by neuraminidase pretreatment.
- Coexpression of HMB45 and muscle-specific antigen (HHF-35) was observed in a subpopulation of AML cells.
- Cells were negative for cytokeratin and S-100 protein.
Conclusions:
- The HMB45 antigen in angiomyolipoma is the same as in melanocytic/melanoma cells.
- These findings suggest a pluripotent cell of origin for AML, capable of divergent differentiation.
- This supports a potential link between melanocytic differentiation and angiomyolipoma genesis.