星形细胞瘤中PTEN、Mdm2的表达及相关性分析

Expression and correlation analysis of PTEN and Mdm2 in astrocytoma

目的:探讨不同组织病理分级的星形细胞瘤中PTEN、Mdm2的表达水平,分析PTEN与Mdm2表达的相关性,并论证癌基因与抑癌基因相互调控的信号转导机制。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的表达水平,并对实验结果进行半定量分析。结果:星形细胞瘤中PTEN、Mdm2的表达率分别是54.4%、41.2%,随着肿瘤恶性程度增加,PTEN的表达率呈下降趋势,而Mdm2的表达率则呈上升趋势,Spearman等级相关分析显示PTEN的表达与星形细胞瘤病理分级呈负相关,Mdm2的表达与分级呈正相关。PTEN阳性表达的37例星形细胞瘤标本中,Mdm2的阳性率是21.6%;而在PTEN阴性表达的31例标本中,Mdm2的阳性率是64.5%,Spearman等级相关分析显示PTEN表达与Mdm2癌蛋白表达呈负相关(P<0.01)。结论:PTEN、Mdm2的表达与星形细胞瘤组织病理分级相关。PTEN表达与Mdm2表达呈负相关,抑癌基因PTEN能够部分下调癌基因Mdm2的表达水平。

Objective To study the expression levels and the correlation between PTEN and Mdm2 in different histopathological grades of astrocytoma and the mechanisms of signal transduction through which PTEN affects Mdm2 expression. Methods The expressions of PTEN and Mdm2 in surgical specimens from 68 patients with brain astrocytoma were detected with immunohistochemical method and the results received semiquantitative analysis. Results The incidences of PTEN and Mdm2 expression were 54. 4% and 41. 2% respectively in astrocytoma. With the grade of astrocytoma increasing, the levels of PTEN protein decreased, and the levels of Mdm2 protein increased. The spearman correlation test showed the grade of astrocytoma was negatively related to PTEN expression and positively related to Mdm2 expression. The incidence of Mdm2 positive expression was 21.6% in 37 cases exhibiting PTEN positive staining, and was 64. 5% in 31 cases exhibiting PTEN negative staining. PTEN was negatively related to Mdm2 expression（P〈0.01）. Conclusion The expressions of PTEN and Mdm2 are related to the histopathological grades of astrocytoma. The expression of PTEN is negatively related to Mdm2 expression, and PTEN expression can inhibit Mdm2 accumulation.