PROGNOSTIC-SIGNIFICANCE OF FLOW-CYTOMETRY DEOXYRIBONUCLEIC-ACID ANALYSIS OF HUMAN OLIGODENDROGLIOMAS

FLOW CYTOMETRY WAS used to determine the deoxyribonucleic acid ploidy and proliferative activity of 60 oligodendrogliomas and oligoastrocyto mas. The relationships among survival, ploidy, proliferation, histolog ical features, and clinical variables were analyzed. Survival was stro ngly associated with the S-phase fraction (P < 0.001). Three groups wi th significantly different survival rates were defined, based on S-pha se fraction ranges of < 3%, 3 to 5.9%, and > 6%. Significant associati ons between survival and age at diagnosis (P < 0.001), tumor grade (P < 0.001), and extent of surgery (P < 0.01) were found also. The poor c orrelation between mitotic figures and survival in oligodendrogliomas that has been reported previously emphasizes the need for an accurate method to measure proliferative activity. Our study demonstrated the u sefulness of the flow cytometry-determined S-phase fraction in this re gard and demonstrated that specific reference ranges could be defined for clinical application. In contrast, the determination of ploidy by flow cytometry was not useful in the evaluation of oligodendrogliomas.