Objective:To explore the correlation of ER expression to the activity of cell proliferation and clinicopathology in brain tumors(astrocytomas

ependynomas

and medulloblastomas).Methods:The expression of ER and proliferating cell nuclear antigen(PCNA) were determined by SP immunohistochemical method in 64 cases of brain tumors tissues.Correlation ER expression with chinicopathological characteristics was studied.Results:The positive rates of ER expression in astrocytomas

ependynomas

and medulloblastomas were 39.47%(15/38)

35.71%(5/14) and 41.60%(5/12) respectively.Maliganat astrocytomas(42.8%) had a significantly higher ER expression rate compared with Benign astrocytomas(33.3%)(P<0.05).ER positive glial tumors had higher PCNA labeling index(LI)compared with ER negative glial tumors(P<0.01).The expression of ER in astrocytomas tissues was significantly related with PCNA.Conclusion:Frequency of ER occurrence is higher in highly malignant astrocytomas.ER expression is correlated with proliferative activity.The expressions of ER in astrocytomas is related to higher rate of cell proliferation and histological grated and may play a pivotal role in astrocytic tumor initiation and regulation of proto-oncogene.