中文摘要：

目的：检测骨肉瘤组织中人第lO号染色体缺失的磷酸酶及张力蛋白同源的基因（PTEN）启动子特定区域的甲基化状态．初步探索PTEN在骨肉瘤发生、发展中的作用。方法：应用基质辅助激光解吸电离飞行时间质谱（MALDI-TOFMS）方法、检测并分析32例骨肉瘤患者的病理组织中及17名正常对照者的外周血中抑癌基因PTEN启动子003区域CpG岛的甲基化状态。结果：骨肉瘤好发于股骨远端（20．9％）、胫骨近端（20．9％1和肱骨远端（16_3％1。骨肉瘤组织中抑癌基因PTEN启动子003区域CpG_1、CpG_3．4、CpG_9、CpG_11．12，CpG_13和CpG_18．19．20的甲基化率高于其在正常人外周血样中的甲基化率（P〈0．05）。结论：PTEN基因启动子高甲基化导致的PTEN基因失活可能参与了骨肉瘤的发生、发展。

英文摘要：

Objective To investigate the promoter CpG islands methylation status of tumor suppressor gene PTEN in osteosarcoma and to investigate the function of PTEN in the pathogenesis of osteosarcoma. Methods Forty-three cases of osteosarcoma were collected. The CpG islands methylation ratio of PTEN promoter 003 domain were detected by MALDI- TOF MS in 32 cases of osteosarcoma and blood samples of 17 normal individuals. Results Forty-three cases of osteosarcoma comprised 20 male （46.5%） and 23 female （53.5%）; male to female ratio was 1：1.15. The ages of patients ranged from 9-74 years, with a median age of 25 and mean age of 30. 20.9% of the osteosarcoma were located in the distal femur, 20,9% in the proximal tibia and 16.3% in distal humerus. The methylatiou ratio of CpG_1, CpG_3.4, CpG9, CpG_I 1.12,CpG_13 and CPG_18.19.20 in PTEN promoter 003 domain was significantly higher than that of normal blood sample control （P〈0.05）. Conclusions High methylation ratio of PTEN promoter may cause the loss of PTEN function and be involved in the pathogenesis of osteosarcoma.