[Relationship of PTEN, Mdm2 and p53 expression in astrocytoma].

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.