A study of apoptosis in brain tumors by in situ end-labeling method.

Recognition of apoptotic cells has recently been facilitated by in situ end-labeling (ISEL) techniques which identify DNA strand breaks. The ISEL assay has been applied in 26 brain tumors, meningiomas, and gliomas of different grade of malignancy in order to determine the apoptotic index (AI). Apoptotic cells were readily found in all the examined tumors; in most cases the AI values were below 1%. Any significant relationship between AI and grade of malignancy could not be determined. However, the AI mean value of the meningiomas was higher than that of gliomas WHO II and III, respectively. Furthermore, it seemed that in the examined gliomas, with the exception of the glioblastoma group, low grade malignancy was related with higher AI values. The latter decreased gradually in the WHO II and III group of tumors, respectively. Our preliminary results indicate that an apoptotic process may play a significant role in brain tumor kinetics and will probably contribute to our understanding of the biologic behavior of those tumors.