Objective To explore the invasiveness of xenografts on chicken embryo chorioallantoic membrane（CAM） after tissue inhibitor of metalloproteinase-2（T IMP-2）gene transfection. Methods Fresh ameloblastoma tissues were minced into 1-2 mm3 and transplanted on the CAM. There were three groups named as control group（Empt）, plasma transfection group（Lipo）, and TIMP -2 gene transfection group（P）. The specimens were respectively investigated by microscope in different spots after implanting. The volume of the xenografts and the weight of xenografts in the termination time of the experiment were recorded. The invasiveness of xenografts was divided into four grades by pathological examination. Western blot analysis was performed to investigate matrix metalloproteinase-2 （MMP-2） and TIMP-2 protein in xenografts. Results Ameloblastoma tissues can survive on CAM and the tumor cells may invade it on 5-7 days after implanting. At 9 d after implanting, the invasiveness grades in P group were 7 in grade 0, 1 in grade 2, 0 in grade 3. The expression of TIMP-2 protein in P group was significantly higher than that in Empt group（P
