[Multivariate analysis of the parameters related to prognosis of astrocytoma]

To investigate the clinical and pathological characteristics of astrocytoma and the factors related to pathologic gradings as well as prognosis in astrocytoma.

120 cases of the astrocytoma with complete clinical data were selected as the study group, of which 94 cases had follow-up data. 20 cases of normal brain tissue and demyelinating plaques with astrocyte hyperplasia were used as the control group. The expression of Ki-67, VEGF, collagen IV and TRT by immunohistochemical staining and detection of TRTmRNA and telomerase RNA by in situ hybridization were studied.

(1) Both astrocytoma and demyelinating lesions showed various positivity for Ki-67. The difference between different gradings of the astrocytoma and non-neoplastic lesions were significant(P < 0.01). Taking 8.5% of Ki-67 expression as threshold, there was significant difference between two survival curves indicating favorable and unfavorable prognosis in the tumor group respectively (P < 0.01). (2) Microvascular changes, such as the density of blood vessels, did not demonstrate any difference between grade I, II astrocytoma and normal tissue, but was significantly increased in grade III and IV astrocytoma and even more in the necrotic area (P < 0.01). The expression of VEGF correlated closely to the density of the blood vessel (P < 0.01). (3) The expression of TRT protein was negative in normal astrocytes but positive in proliferative disease and astrocytoma. The intensity of the positivity was enhanced by the grading of the tumor and correlated with the prognosis (P < 0.01). The expression of hTR, TRTmRNA was less than that of TRT but was well correlated to TRT expression.

Use of the cox-regression model in multivariate analysis shows that there are six parameters closely related to the prognosis of astrocytoma, of which the pathological grade being the most critical factor. Ratio of Ki-67 positivity, age of patient, duration of symptoms are also important factors, while microcystic changes in the tumor and expression of VEGF are independent favorable factors for astrocytoma.