[Diagnostic and/or prognostic value of the nuclear level determination of desoxyribonucleic acid (DNA) in nervous system tumors].

The diagnostic and prognostic value of the DNA ploidy level (nuclear DNA content) was studied in a series of 847 tumours of the nervous system. This series included 93 nerve sheath tumours, 224 meningiomas, 389 neuro-epithelial tissue tumours, 46 primitive neuroectodermal tumours (retinoblastomas, medulloblastomas, neuroblastomas, etc.) and 95 brain metastases. The DNA ploidy level determination was carried out by means of the computer-assisted microscope analysis (digital cell image analysis) of Feulgen-stained nuclei. The results show that the DNA ploidy level does not contribute significant diagnostic information when tumours are analyzed individually. Indeed, some tumours which are definitely benign like certain schwannomas and meningiomas can exhibit very high levels of aneuploidy, while some highly malignant tumours like certain glioblastomas and neuroblastomas can be diploid. In contrast to its weak diagnostic value, the DNA ploidy level appears to be a powerful prognostic factor with respect to the supratentorial astrocytic tumours of the adult. Indeed, patients with hypertriploid astrocytic tumours exhibit a survival period which is significantly longer when compared to that of patients with non-hypertriploid astrocytic tumours. These hypertriploid astrocytic tumours could be involved in a process of biological degeneration when reference is made to their proliferation activity which is significantly weaker than that of non-hypertriploid tumours.