Survivin Expression in Glioblastomas Correlates with Proliferation, but not with Apoptosis

Abstract

Background: Survivin is expressed in proliferating tissues and in tumors. It is a member of the inhibitory apoptosis protein (IAP) family known to regulate mitosis and to inhibit apoptosis. It has therefore been regarded as a target for therapies. In malignant gliomas it increases with malignancy, even though in glioblastomas it does not seem to correlate with outcome. Materials and Methods: Survivin was immunohistochemically studied in 39 selected viable glioblastoma areas belonging to 20 cases which were assayed for apoptosis, using a TUNEL assay, caspase-3, poly(ADP-ribose)polymerase 1 (PARP-1), Bid (BH3-interacting domain death agonist) and with the proliferation index Ki-67/MIB-1 and mitotic index (MI). Results: A positive linear correlation was found between the survivin labelling index (LI) and the Ki-67/MIB-1 LI and MI. No inverse correlation was found with apoptosis. Conclusion: This double behavior can be attributed to mechanisms mediating survivin activity, either as a mitosis regulator and apoptosis inhibitor, and should be taken into account in therapeutic strategies using survivin.