BCL-2 PROTEIN EXPRESSION IN ASTROCYTOMAS IN RELATION TO PATIENT SURVIVAL AND P53 GENE STATUS

bcl-2 protein expression was characterized in a series of 58 astrocyto mas from 21 pediatric and 37 adult patients. As part of a continuing a ttempt to define relevant prognostic factors which may predict clinica l outcome, we have determined the impact of bcl-2 accumulation in mali gnant astrocytes on the length of patient survival. Aberrant overexpre ssion of bcl-2 protein in tumor cells was detected in 57% (12 of 21) o f pediatric and 73% (27 of 37) of the adult cases. Among pediatric pat ients, the median survival in months showed no relationship with the i ncidence of bcl-2-positive tumors. Among the adult patients, a favorab le prognostic indicator was low-tumor grade (P = 0.05). bcl-2-positive tumors occurred with similar frequencies in WHO grades III and IV of malignancy. When bcl-2 expression in tumor cells was tested as a varia ble to predict for patient survival, the 6 patients without bcl-2 expr ession among 23 adult patients with grade IV tumors had a shorter medi an survival. The same 58 tumors had been previously analyzed for alter ations of p53: A pediatric and 16 adult tumors had p53 gene mutations. There was no significant difference in median survival related to p53 gene status. There was no relationship between bcl-2 expression and p 53 gene status: approximately equal numbers of tumors with either wild -type or mutant p53 were bcl-2 negative or bcl-2 positive. bcl-2 expre ssion is high (40-100%) among other tumors of the central nervous syst em which also show low malignant potential. Up-regulation of bcl-2 in malignant astrocytes or constitutive expression in some tumor types ma y be a factor leading to a more favorable clinical outcome.