title: Diagnostic utility of aP2/FABP4 expression in soft tissue tumours.
abstract: Adipocyte P2 (aP2), also known as fatty acid-binding protein 4 (FABP4), is a fatty acid-binding protein found in the cytoplasm of cells of adipocyte differentiation. In this study, we examined a large number of soft tissue tumours with a commercial polyclonal anti-aP2/FABP4 antibody and a newly developed mouse monoclonal antibody raised against this protein to determine the diagnostic utility of aP2/FABP4 as a marker of tumours of adipose differentiation. A mouse monoclonal antibody, clone 175d, was raised against a mixture of synthetic peptides corresponding to the amino acid sequence of residues 10-28 and 121-132 of the human aP2/FABP4 protein. Antigen expression with polyclonal and monoclonal antibodies was immunohistochemically determined in paraffin sections of normal adipose tissue and a wide range of benign and malignant primary soft tissue tumours (n = 200). aP2/FABP4 was expressed around the cytoplasmic lipid vacuole in white and brown fat cells in benign lipomas and hibernomas. Immature fat cells and lipoblasts in spindle cell/pleomorphic lipoma, atypical lipomatous tumour/well-differentiated liposarcoma, myxoid/round cell liposarcoma and pleomorphic liposarcoma also reacted strongly for aP2/FABP4. No specific staining was seen in non-adipose benign and malignant mesenchymal and non-mesenchymal tumours. aP2/FABP4 is expressed by mature and immature fat cells and is a marker of tumours of adipose differentiation. Immunophenotypic aP2/FABP4 expression is useful in identifying lipoblasts, and immunohistochemistry with polyclonal/monoclonal anti-aP2/FABP4 antibodies should be useful in distinguishing liposarcoma from other malignancies, particularly round cell, myxoid and pleomorphic soft tissue sarcomas.
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal and Sciences, University of Oxford, Nuffield Orthopaedic Centre, Oxford, OX7, HE, UK.
authors.forename: T G
authors.initials: TG
authors.lastname: Kashima
authors.forename: H
authors.initials: H
authors.lastname: Turley
authors.forename: A
authors.initials: A
authors.lastname: Dongre
authors.forename: F
authors.initials: F
authors.lastname: Pezzella
authors.forename: N A
authors.initials: NA
authors.lastname: Athanasou
mesh_terms: D000818:Animals; D050556:Fatty Acid-Binding Proteins / Q000032:analysis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008067:Lipoma / Q000737:chemistry; D008080:Liposarcoma / Q000737:chemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D012983:Soft Tissue Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000473:pathology
chemical_list: C493410:FABP4 protein, human; D050556:Fatty Acid-Binding Proteins