ROLE OF APOPTOSIS IN THE PROGNOSIS OF OLIGODENDROGLIOMAS

Prognostic factors in oligodendrogliomas are not well defined, even co nsidering the labeling index of proliferation markers. As in other neu roepithelial tumors, the difficulty in calculating cell loss may contr ibute to this uncertainty. Proliferation markers Ki-67/MIB.1 and PCNA, mitoses, apoptotic nuclei, p53 and bcl-2 expression were investigated in 98 oligodendrogliomas. Apoptosis was assessed by the aspect of nuc lei, by in situ end-labeling (ISEL) technique and by c-Jun immunohisto chemical demonstration. The Bcl-2 also was immunohistochemically studi ed for its anti-apoptotic role. Mitotic index (MI), labeling index (LI ) for MIB.1 and PCNA and apoptotic index (AI) were calculated and comp ared among themselves and with histology and survival. It was found th at AI correlated with MI (p = 0.001) and was significantly higher in a naplastic than in classic oligodendrogliomas (p = 0.001). Apoptosis oc curred only slightly more frequently in cases with high LIs for prolif eration markers (MIB.1 and PCNA) (p = non-significant) and it was defi nitely higher in p53-positive cases (p = 0.008). It did not correlate with bcl-2 which was poorly expressed in oligodendrogliomas, with the exception of cells with astrocytic features. Apoptotic index correlate d very weakly with survival (p = 0.05); therefore, it cannot be consid ered a highly reliable prognostic factor in oligodendrogliomas. (C) 19 97 Elsevier Science Ltd.