星形细胞瘤中PTEN、Mdm2和p53表达的相关性研究

Relationship of PTEN,Mdm2 and p53 expression in astrocytoma

目的 探讨不同组织病理分级的星形细胞瘤中PTEN、Mdm2和p5 3的表达水平 ,并分析PTEN影响Mdm2和p5 3表达的信号转导机制。方法 采用免疫组织化学方法检测 6 8例星形细胞瘤标本中 ,PTEN、Mdm2和p5 3的表达水平。结果 星形细胞瘤中 ,PTEN、Mdm2和p5 3的表达水平分别为 5 4 .4 % (37/ 6 8)、4 1.2 % (2 8/ 6 8)和 4 5 .6 % (31/ 6 8)。PTEN阳性标本中 ,Mdm2的表达率 (2 4 .3% ,9/ 37)与PTEN阴性标本中该蛋白的表达率 (6 1.3% ,19/ 31)相比 ,差异有显著性 ,统计学分析显示 ,PTEN表达与Mdm2表达呈负相关 (P <0 .0 1)。Mdm2表达和p5 3表达一致 ,符合率为 6 6 .2 % (45 / 6 8) ,两者的表达密切相关 (P <0 .0 5 )。结论 PTEN、Mdm2和p5 3表达与星形细胞瘤的组织病理分级相关 ;抑癌基因PTEN可以下调癌基因Mdm2的表达水平 ;Mdm2和p5 3的表达存在一致性。

Objective To study the incidence of PTEN, Mdm2 and p53 expression in different histopathological grades of astrocytoma and the signal transduction mechanism through which PTEN affects Mdm2 and p53 expression. Methods Surgical specimens from 68 brain astrocytoma patients were analyzed to detect PTEN, Mdm2 and p53 expression by 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). The positive incidence of Mdm2 was 24.3% (9/37) in 37 cases with PTEN expression and 61.3%(19/31)in 31 cases without, which had a negative correlation between Mdm2 expression and PTEN expression(P<0.01). Eighteen cases showed Mdm2(+)/p53(+) and 27 cases showed Mdm2(-)/p53(-). A significant correlation was found between Mdm2 and p53 expression(P<0.05). Conclusion The histopathological grade of astrocytoma is correlated with the loss of PTEN expression, Mdm2 amplification and p53 mutation. Mdm2 amplification, being in accordance with p53 mutation, can be inhibited by PTEN expression.