Expression of Bcl-2, Bcl-x, and Bax proteins in astrocytomas in relation to patient survival

The Bcl-2 family is composed of a group of related proteins that either prevent or promote apoptosis. This study was undertaken to assess the prognostic value of Bcl-2, Bcl-x, and Bax in patients with astrocytomas. Tissue samples from 104 astrocytomas (WHO grade 2, 21 cases: grade 3, 49 cases; grade 4, 34 cases), including 68 primary and 36 recurrent tumors, were examined immunohistochemically for Bcl-2, Bcl-x, and Bax expression. Patient charts were reviewed for clinical presentation, and survival was followed. The mean values of the Bcl-2, Bcl-x, and Bax labeling indexes (LI) were 15.9 +/- 13.1%, 53.2 +/- 35.3%, and 25.9 +/- 23.2%, respectively. Statistical analysis showed that the Bcl-x LI of high-grade (grade 3 or 4) astrocytomas was higher than that of low-grade (grade 2) tumors (P = 0.0064). There were no significant differences in patient survival between the high- and low-LI groups of Bcl-2, Bcl-x, and Bax. Since the mechanism and regulation of apoptosis are still unclear, it seems difficult to use the Bcl-2 family as a biological marker in predicting the prognosis of patients with astrocytomas.