Immunohistochemical detection of c-fos and c-jun expression in osseous and cartilaginous tumours of the skeleton.
The products of c-fos and c-jun proto-oncogenes form the heterodimeric complex AP-1 (activator protein 1), which play an important part in the control of bone cell proliferation and differentiation and in the development of bone tumours. We examined the expression of c-fos and c-jun in a series of 52 primary skeletal neoplasms, using an immunohistochemical method on formalin-fixed, paraffin-embedded sections. The expression of c-fos and c-jun was restricted to bone-forming lesions, while cartilaginous tumours were devoid of immunoreactivity. In benign osteoblastic lesions moderate c-fos and c-jun expression was found in 2 cases (18.1%). The highest levels of c-fos and c-jun expression were detected in high-grade central osteosarcomas (7 of 15 cases with moderate/diffuse expression) while 1 telangiectatic osteosarcoma, 2 low-grade central osteosarcomas, 1 low-grade periosteal osteosarcoma and 7 low-grade parosteal osteosarcomas were either negative or had low expression. The high-grade component of a dedifferentiated parosteal osteosarcoma showed diffuse immunoreactivity for both oncoproteins. Comparison of c-fos and c-jun expression by histological grade showed that high-grade osteosarcomas had a significantly higher expression of both oncoproteins than did low-grade osteosarcomas (P = 0.01, Fisher's exact test). Thus, c-fos and c-jun overexpression may be implicated in the development of high-grade osteosarcomas, but they appear to have little or no relevance for the development of low-grade osteosarcomas and cartilaginous skeletal neoplasms.
Institute of Anatomic of Pathology, University of Florence, Italy.
A
A
Franchi
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A
Calzolari
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G
Zampi
D001859:Bone Neoplasms / Q000378:metabolism*; D002812:Chondroma / Q000378:metabolism; D002813:Chondrosarcoma / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D009372:Neoplasms, Connective Tissue / Q000378:metabolism*; D018215:Osteoblastoma / Q000378:metabolism; D010016:Osteoma / Q000378:metabolism; D012516:Osteosarcoma / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*
D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun