[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).


CONCLUSIONS
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.
Department of Pathology, Medical College of Jinan University, Guangzhou 510632, China.
Xue-yun
XY
Zhong
Yan-hua
YH
Sun
Yun-xian
YX
Chen
D000293:Adolescent; D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000737:chemistry* / Q000473:pathology; D002648:Child; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009687:Nuclear Proteins; D051059:PTEN Phosphohydrolase; D010744:Phosphoric Monoester Hydrolases / Q000032:analysis*; D011518:Proto-Oncogene Proteins / Q000032:analysis*; D051736:Proto-Oncogene Proteins c-mdm2; D015398:Signal Transduction; D016159:Tumor Suppressor Protein p53 / Q000032:analysis*; D025521:Tumor Suppressor Proteins / Q000032:analysis*
D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human