Flow cytometric analysis of cellular DNA content in human astrocytomas and oligodendrogliomas

This report presents a flow-cytometric analysis of cellular DNA in biopsies and primary cell cultures of 21 human astrocytomas and 19 oligodendrogliomas. A distinct correlation between histological dedifferentiation and pathological DNA distribution was found. Classification was made according to increasing histological anaplasia, corresponding to a four-grade scale and proliferation index (PI). Four types of gliomas were defined according to characteristic DNA patterns and proliferative activities in comparison to their histological grading: 1. purely diploid DNA patterns with low 4C (premitotic) peaks and PI values up to 10 in well-differentiated gliomas; 2. increase of tetraploid cells and PI of 10-16 in tumors with histological grades II or II-III; 3. diploid-tetraploid DNA distribution with PI values up to 30-31 and malignancy grade III; 4. polyploid and aneuploid karyograms with excessive 4C increase, emerging in grade III and especially grade III-IV of these gliomas. Varying DNA distribution during tumor development could be observed in a malignant transformation of an oligodendroglioma I to a glioblastoma after a course of 3 1/2 years. A more detailed subdivision of these tumors according to their DNA content and proliferative activity was achieved. With the exception of occasional variation in karyograms, DNA distribution usually remained stable in primary tissue cultures (PTC).