Abstract: Objective:To investigate the expressions of nuclear factor-B(NF-B),matrix metalloproteinase-9(MMP-9) and cyclooxygenase-2(COX-2) in osteosarcoma and analyze their relationship in angiogenesis.Methods:The expressions of NF-B,MMP-9 and COX-2 proteins in 52 specimens with osteosarcoma were determined by S-P immunohistochemical staining method,and 40 specimens of osteochondroma were served as control.Microvessel density were calculated with anti-CD34 monoclonal antibody stainning.Results:The positive expressions of NF-B,MMP-9 and COX-2 in osteosarcoma were significantly higher than those in osteochondroma(P0.05),there were positive correlations between the expressions of NF-B and MMP-9,NF-B and COX-2,and the close correlations were found between NF-B,MMP-9,NF-B and microvessel density.Conclusions:The expressions of NF-B,MMP-9 and COX-2 in osteosarcoma are all high.The three indexes may promote angiogenesis of osteosarcoma.