Malignant gliomas--ploidy and DNA-content before and after therapy

DNA ploidy and S-phase percentage from nine malignant gliomas (four glioblastomas, four anaplastic astrocytomas grade 3 and one anaplastic oligoastrocytoma grade 3) have been estimated by single cell cytophotometry on biopsy and necropsy specimens. All gliomas from biopsy material showed, with the exception of two diploid tumours, a polyploid-aneuploid DNA-pattern and stem-lines of different ploidy. The most frequent stem-lines were diploid and hyperdiploid. In necropsy material, following treatment i.e. operation and combined drug and radiation therapy, the heterogeneous nature of all malignant gliomas persisted. From seven aneuploid-polyploid gliomas four showed an elevation and three of them a decrease of DI values. Diploid tumors remained diploid. Because of marked heterogeneity of ploidy patterns and the small number of tumors investigated, ploidy changes could not be used for estimation of therapy efficacy and prognosis. Further studies will be necessary to answer this question.