Distribution of activated caspase-3 in relation with apoptosis in human malignant gliomas

Activated caspase-3 has been immunohistochemically studied in 30 glioblasto mas. Its distribution has been compared with that of apoptotic nuclei demon strated by terminal dUTP nick-end labeling (TUNEL) and morphology. The best procedure for the demonstration of caspase-3 requires formalin fixation, f ollowed by Carnoy fixation, with microwave irradiation. The number of posit ive cells is lower than that of apoptotic nuclei shown by TUNEL technique, especially in perinecrotic pseudo-palisadings, and there are also qualitati ve variations. Positive staining occurs in nuclei, cytoplasms or in both ce ll compartments. The interpretation of Caspase-3 positive staining is based on its crucial position in the final pathway to apoptosis and on the mecha nisms by which it cleaves cytoplasmic and nuclear proteins among which inhi bitory/caspase-activated DNase system is included. (C) 2001 Elsevier Scienc e Ireland Ltd. All rights reserved.