Bone morphogenetic proteins in bone tumors.
Bone morphogenetic proteins (BMPs), inducers of ectopic bone formation in vivo, are present in a number of osteosarcomas. BMPs are responsible for reactive bone formation, including periosteal reactions by normal osteoblasts, rather than production of tumorous osteoid by tumor cells. Osteosarcomas producing BMPs contain less-differentiated mesenchymal cells, resulting in a poorer prognosis for those patients. BMPs are also expressed in malignant fibrous histiocytomas (MFHs) of bone and dedifferentiated chondrosarcomas exhibiting undifferentiated features. However, BMPs in MFH do not show any osteoinductive activity in vivo, suggesting that those BMPs may be inactive forms and have additional functions unrelated to bone formation. Among benign bone tumors, BMPs are expressed in osteoid osteomas or osteoblastomas and effect reactive bone formation such as a surrounding sclerosis. BMPs and a BMP receptor (BMPRIB) are also detected in the cartilage cap in osteochondroma, suggesting that BMP signaling via BMPRIB might be involved in the pathogenesis of osteochondroma. Clinically, BMPs have utility as diagnostic and prognostic markers for characterizing the stage of differentiation of mesenchymal cells and mesenchymal tumors, and they may be of value in predicting the prognosis of sarcoma patients. This article reviews the accumulated information on BMPs in bone tumors, including the most recent findings, and discusses the biological and clinical significance of BMPs in bone tumors.
Yoshikawa
Hideki
H
Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita 565-0871, Japan.
Nakase
Takanobu
T
Myoui
Akira
A
Ueda
Takafumi
T
D000818:Animals; D055415:Bone Morphogenetic Protein 4; D055418:Bone Morphogenetic Protein 6; D052006:Bone Morphogenetic Protein Receptors, Type II; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D001859:Bone Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000503:physiopathology; D002454:Cell Differentiation; D006801:Humans; D010006:Osteoblasts / Q000378:metabolism; D012516:Osteosarcoma / Q000378:metabolism* / Q000401:mortality; D011379:Prognosis; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism
C525809:BMP4 protein, human; C525816:BMP6 protein, human; D055415:Bone Morphogenetic Protein 4; D055418:Bone Morphogenetic Protein 6; D019485:Bone Morphogenetic Proteins; D017346:Protein Serine-Threonine Kinases; C498218:BMPR2 protein, human; D052006:Bone Morphogenetic Protein Receptors, Type II