目的: 探讨不同组织病理分级的星形细胞瘤中PTEN、Mdm2和p53的表达水平,并分析PTEN影响Mdm2、p53表达的信号转导机制.方法: 采用免疫组织化学方法检测68例星形细胞瘤标本中PTEN、Mdm2和p53的表达水平.结果: 星形细胞瘤中PTEN、Mdm2、p53的表达水平分别是54.4%(37/68)、41.2%(28/68)、45.6%(31/68).PTEN阳性标本中Mdm2的表达率(24.3%,9/37)与PTEN阴性标本中该蛋白的表达率(61.3%,19/31)相比差异显著,统计学分析显示PTEN表达与Mdm2表达呈负相关(P＜0.01).Mdm2表达和p53表达一致符合率达66.2%(45/68),两者的表达密切相关(P＜0.05).结论: (1)PTEN、Mdm2和p53表达与星形细胞瘤的组织病理分级相关.(2)抑癌基因PTEN可以下调癌基因Mdm2的表达水平.(3)Mdm2和p53的表达存在一致性.%AIM: This investigation was done to show the incidence of PTEN, Mdm2 and p53 expression in different histopathological grades of astrocytoma and the mechanisms of signal transduction through which PTEN affects Mdm2 and p53 expression. METHODS: The surgical specimens from 68 brain astrocytoma patients were analysed to detect PTEN, Mdm2 and p53 expression with immunohistochemical method. RESULTS: The incidence of PTEN, Mdm2 and p53 expression was 54.4%(37/68), 41.2%(28/68) and 45.6%(31/68) respectively in astrocytoma. The positive incidence of Mdm2 protein in 37 cases with PTEN positive expression was 24.3% (9/37) and in 31 cases with PTEN negative expression was 61.3%(19/31).There was an inverse correlation between Mdm2 expression and PTEN expression(P＜0.01). 18 cases showed Mdm2+/p53+ expression and 27 cases showed Mdm2-/p53- expression. A significant correlation was found between Mdm2 and p53 expression(P＜0.05).CONCLUSIONS: These findings strongly indicated that (1) There was a correlation between histopathological grade of astrocytoma and loss of PTEN expression, Mdm2 expression, p53 expression and (2) PTEN expression inhibited Mdm2 expression and (3) Mdm2 expression was in accordance with p53 expression.
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