冯和林　郑丽华

Osteosarcoma (OS) is derived from the initial mesenchymal cells, the primary bone tissue and is the most common primary malignant tumors in children and youth. The annual worldwide incidence rate of osteosarcoma is 4/million and of its peak incidence is 15-19 years. OS is prone to transfer that about 20% of patients in the initial diagnosis are confirmed with lung metastasis, and other 40% of patients are diagnosed shortly after transfer. 80% of the transfer occurs in the lung, and is not sensitive to chemotherapy targeted therapy. Metastasis in patients with 5-year survival rate is 20%, and the survival rate of the osteosarcoma patients without transfer is 65%. Most of the OS patients died of transfer complications, and the treatment of metastatic OS was still a problem faced by orthopedic surgeons. The researches of biological characteristics and behaviors of metastatic OS cell may be able to bring new methods for the treatment of metastatic OS. We will state the process of metastasis of osteosarcoma, the osteosarcoma transfer process includes metastasis and invasion of osteosarcoma cells (osteosarcoma cells first pass through the explanation of the protease, separation), survival in the circulatory system ( the anti-apoptotic mechanisms is very important, the NF-kB pathway, Wnt/β- catenin pathway and Fas and FasL in this process as apoptotic signaling pathways down to play an important role in the anti-apoptotic), to blind to the immune system (down-regulation of tumor cell HLA molecules, Fas down invasion or destruction of Fas pathway downstream elements to provide advantages of metastatic tumor cells), stagnation and outside the organization (OS endothelial cell tropism endothelial interactions of tumor cells and transfer reason for predilection sites), adhesion (Ezrin support cell surface adhesion proteins play an important role in cell-cell interaction and are listed as an important factor in the survival of metastatic cells), tissue sleep (the function of anti-apoptotic gene Bcl-XL in dormant period in the cell survival), angiogenesis (the formation of new blood vessels plays an important role in the transfer of the OS, fast-growing tumor hypoxia can lead to a variety of promoting endothelial growth factor production) and proliferation (each of the above steps for the tumor provides a solid foundation for growth, proliferation represents the success of tumor metastasis). The osteosarcoma cell transfer process is very complex, and many of the molecules get involved in the transfer of osteosarcoma. Each step will play a crucial role in the transfer of osteosarcoma. The osteosarcoma cells with successful transfer are very rare, so blocking of one process of tumor cell metastasis will greatly reduce the chance of metastasis of osteosarcoma. This article will introduce the OS transfer mechanisms as follow.