The Expression And Relatinship Of PTEN, Mdm2 And P53 In Human Astrocytoma

Objective 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. With the grade of astrocytoma increasing the levels of PTEN protein decreased, on the other hand the levels of Mmd2, p53 protein increased. There was a negative correlation between PTEN expression and grade of astrocytoma while there was a positive correlation between Mdm2, p53 expression and grade of astrocytoma by using the Spearman Correlation test to analyse the data. The incidence of Mdm2 positive expression was 21.6% (8/37) in 37 cases exhibiting PTEN positive staining; whereas the incidence of Mdm2 positive expression was 64.5% (20/31) in 31 cases exhibiting PTEN negative staining. In statistics, there was an inverse correlation between PTEN and Mdm2 expression (P<0.01) . 18 cases exhibited both Mdm2 and p53 positive expression and 27 cases exhibit both Mdm2 and p53 negative expression, so the incidence of simultaneous staining or no staining was 66.2% (45/68) . Using the Spearman Correlation test to analyse the data, a positive correlation was found between Mdm2 anip53 expression (P<0.01) .Conclusion (1) There was a correlation between histopathological grades of astrocytoma and loss of PTEN expression, Mdm2 accumulation, p53 expression. (2) There was an inverse correlation between PTEN and Mdm2 expression, and PTEN expression inhibits Mdm2 accumulation. (3) Mdm2 accumulation was in accordance with p53 expression. A positive correlation was found between Mdm2 and p53 expression. Mdm2 and p53 co-expression was the biological character of high grade tumor.