BACKGROUND: Osteosarcoma is the most common type of bone tumor and generally occurs between the age of 10 to 25; moreover, in clinical practice osteosarcoma is found to occur more often in minority nationalities in Xinjiang Autonomous Region. Do its incidence and prognosis vary between nationalities at gene levelOBJECTIVE: To observe the different expressions of p53, bcl-2 and proliferative cell nucleus antigen (PCNA) gene during the development of osteosarcoma between various Xinjiang nationalities.DESIGN: Non-randomized comparative experiment taking clinical pathological specimens as subjects.SETTING: Immunohistochemical Laboratory, the Pathological Center of Xinjiang Medical University.PARTICIPANTS: Totally 52 pieces of specimen were obtained from excised osteosarcoma tissues in the Pathological Department, the First Affiliated Hospital of Xinjiang Medical University, and the Pathological Department, the First Affiliated Hospital of Shihezi University, between January 1,1984 and December 31, 2001. The 52 cases of osteosarcoma included 29cases derived from male patients and 23 from female patients; among them there were 12 cases of Kazak minority, 17 cases of Uygur minority and 23cases of Han nationality. Other 32 specimens were obtained from 32 patients with tumor-like lesions (such as osteofibrous dysplasia or fibrous dysplasia), including 7 cases of Kazak minority, 11 cases of Uygur minority,and 14 cases of Han nationality. The informed consent was obtained from the patients.METHODS: This experiment was carried out at the Immunohistochemical Laboratory, the Pathological Center of Xinjiang Medical University. LSAB method was used to detect p53, bcl-2 and PCNA expression in the two groups. The first antibody was re placed by PBS as blank control, and the available positive expression was taken as positive control. P53 protein and PCNA were observed to express in cell nucleus, appearing obvious redbrown granules with positive expression, whereas Bcl-2 protein was expressed in cytoplasm.lationship between the expression of Bcl-2, p53 and PCNA in osteosarcoma.of different nationalities: The expression of p53, bcl-2 and PCNA in Kazak minority, Uygur minority and Han nationality was not remarkable p53, bcl-2 and PCNA in osteosarcoma and bone tumor-like lesions: The expression of P53, Bcl-2 protein and PCNA in osteosarcoma was remarkably higher than that in tumor-like lesions (42.31% vs. 3.13 %, 59.62%sion of bcl-2, p53 and PCNA in osteosarcoma: There was a close correlation between bcl-2 and p53, as well as between bcl-2 and PCNA in osteosarcoma tissues (X2 =5.818 2, 4.900 0, P＜0.05).CONCLUSION: The results indicate that there was no statistical difference between various nationalities in the expression of p53, bcl-2 and PCNA, as well as osteosarcoma differentiation. Suggesting that these genes may share the common regulation during the development of osteosarcoma,which is less associated with their nationality-related hereditary background.