Preferential expression of Fas/APO1 (CD95) and apoptotic cell death in perinecrotic cells of glioblastoma multiforme

Fas/APO-1 (CD95)-mediated apoptosis is one of the major mechanisms of programmed cell death. We have previously shown by reverse transcriptase-polymerase chain reaction that Fas is frequently expressed in malignant gliomas [Tachibana et al. (1995) Cancer Res 55: 5528-5530]. In this study, we assessed Fas expression in astrocytomas using a polyclonal anti-Fas antibody. Immunoreactivity to Fas was detected in 1 out of 9 (11%) low-grade astrocytomas (WHO grade II), 2 of 11 (11%) anaplastic astrocytomas (WHO grade III) and in 13 of 15 (87%) glioblastomas (WHO grade IV). In glioblastomas, Fas expression was almost exclusively observed in glioma cells surrounding foci of necrosis. In these perinecrotic areas, there was also an accumulation of glioma cells undergoing apoptosis, as detected by in situ nick-end labeling. This suggests that Fas-mediated apoptosis may play a role in the pathogenesis of necrosis which constitutes a histological hallmark of glioblastoma multiforme.