aP2 Protein Expression as a Diagnostic Marker in Soft Tissue Tumours

[摘要] Purpose/Methods:The aP2 gene product (aP2 protein) is known to be expressed by preadipocytes and other immature fatcells in vitro. A mouse monoclonal antibody raised against an 18 amino acid segment of the aP2 protein was found to reactwith lipoblasts and fetal fat cells in paraffin sections of soft tissue tumours of adipose differentiation. In this immunohistochemicalstudy, we have further examined the diagnostic utility of aP2 expression in distinguishing tumours of adipose differentiationfrom other benign and malignant soft tissue tumours.Result and discussionaP2 was strongly expressed by lipoblasts in lipoblastomas and all types of liposarcoma as well as brownfat cells in hibernomas. Optimal conditions for immunohistochemical identification of lipoblasts in tumours of adipose differentiationwas noted when the antibody was diluted 1:30 to 1:50. Small lipoblast-like fat cells in pleomorphic lipoma andspindle cell lipoma also showed variable staining for aP2 at this dilution of the antibody. Most benign and malignant softtissue tumours were distinguished by their absence of staining for aP2 protein, but some cases of myxoma, malignant fibroushistiocytoma, synovial sarcoma and leiomyosarcoma contained tumour cells which reacted for aP2. aP2 protein expressionis likely to prove a useful means of distinguishing lipoblasts in liposarcoma but it should be used as part of a tumour panelto exclude expression in other forms of mesenchymal tumour.

[学科分类] 肿瘤学